[From the U.S. Government Printing Office, www.gpo.gov]






                            United Nations       World               United States Army Corps of               May 1990
                            Environment          Meteorological      Engineers, Environmental Protection
                            Programme           Organization         Agency, National Oceanic and
                                                                        Atmospheric Administration
                            Changing Climate and the Coast
                            Volume 2: Western Africa, the Americas,
                            the Mediterranean Basin, and the Rest of Europe








             -VED Stq,@,'

                                                               4V








                OF



                                                                           .er,









                                                                                            kA@




                                               Report to the Intergovernmental Panel on Climate Change
                                                  from the Miami Conference on Adaptive Reponses
                                                         to Sea Level Rise and Other Impacts
                                                               of Global Climate Change


















































                                              Library of Congress Cataloging-ins-Publication Data

                                              Changing Climate and the Coast / edited by James G. Titus.
                                                 Papers presented at workshop held in Miami, Fla, Nov 27-Dec 1, 1989,
                                                sponsored by the US Environmental Protection Agency and others.
                                                 Contents: vol. 1. Adaptive responses and their economic, environ-
                                                mental, and institutional implications-vol. 2. Western Africa, the Ameri-
                                                cas, the Mediterranean basin, and the rest of Europe
                                                 Includes bibliographical references. ,
                                                 1. Global warming-Congresses. 2. Climatic Changes-Congresses.
                                                3. Sea level--Congresses. I. Titus, James G. 11. United States Environ-
                                                mental Protection Agency.
                                                QC981.8.G56C55 1990                                             90-2741
                                                333.91'7--dc2O                                                     CIP









         CHANGING CLIMATE AND THE COAST

                    VOLUME 2: WESTERN AFRICA, THE AMERICAS,
              THE MEDITERRANEAN BASIN, AND THE REST OF EUROPE




                REPORT OF THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE
                    FROM THE MIAMI CONFERENCE ON ADAPTIVE RESPONSES TO
                             SEA LEVEL RISE AND OTHER IMPACTS OF
                                      GLOBAL CLIMATE CHANGE




                                                                     PEPAFTMFNT
                                                                                OF COMMERCE NOAA
                                                                        @[""'ICES CENTER
                                                                     @"H NOrlSON AVENUE
                                                                            SC
                                                                                29405-2413
                                               Edited by

                                            James G. Titus
                                 U.S. Environmental Protection Agency


                                         with the assistance of

                                            Roberta Wedge

                                             Norbert Psuty
                                           Rutgers University

                                             Jack Fancher
                          U.S. National Oceanic and Atmospheric Administration


                                      ftOP*XtY Of CSC Library


          The opinions expressed herein are solely those of the authors and unless noted otherwise do not necessarily
          represent official views of any of the sponsoring agencies or the Intergovernmental Panel on Climate
          Change.










                                           TABLE OF CONTENTS


           VOLUME 2                                                                          Page

           V.     REGIONAL STUDIES

               A. WEST AFRICA    . . . . . . . . . . . . . . . . . . . . . . . . . . .           I

                  Adjustments to the Impact of Sea Level       Rise Along the West and
                  Central African Coasts    . . . . . . . . . . . . . . . . . . . . . .          3
                  A.C. The

                  The Gulf of Benin:     Implications of Sea    Level Ri se for Togo and
                  Benin . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . .          13
                  Kolawole S. Adam

                  Coastal Erosion and Management Along the Coast of Liberia       . . . . .    25
                  Eugene H. Shannon

                  Impact of Sea Level Rise on the Nigerian Coastal Zone      . . . . . . .     49
                  L.F. Awosika, A.C. Ibe, and M.A. Udo-Aka

                  Responses to the Impacts of Greenhouse- Induced Sea Level Rise on
                  Senegal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .         67
                  Isabe77e Niang


                  Response to Expected Impact of Climate Change on the Lagoonal and
                  Marine Sectors of Cote D'Ivoire    . . . . . . . . . . . . . . . . . .       89
                  PhHibert Koffi Koffi, Nassera Kaba, and Soko G. Zabi

                  Implications of Global Warming and Sea Level Rise for Ghana       . . . .    93
                  J.F. Abban

                  Sociocultural Implications of Climate Change and Sea Level Rise in
                  the West and Central African Regions      . . . . . . . . . . . . . . .     103
                  0. Ojo

               B. MEDITERRANEAN    . . . . . . . . . . . . . . . . . . . . . . . . . .        113

                  Impacts of Global Climate Change in the Mediterranean Region:
                  Responses and Policy Options     . . . . . . . . . . . . . . . . . .        115
                  G. Sestini

                  Impacts of Climate Change on the Socioeconomic Structure and
                  Activities in the Mediterranean Region      . . . . . . . . . . . . . .     127
                  Ante Baric









                      Venice: An Anticipatory Experience of Problems Created by Sea Level
                      Ri se   . . . . . . . . . . . . . . . . . . . . . . .        . . . . . . . .    139
                      A. Sbavag7ia, C. C7ini, F. De Siervo, and G. Ferro

                      Implications of Sea Level Rise for Greece        . . . . . . . . . . . . .      161
                      Hampik Marouklan

                      Impacts of Sea Level Rise on Turkey       . . . . . . . . . . . . . . . .       183
                      Oguz Erol

                      The Influence of Sea Level Rise on the Natural and Cultural
                      Resources of the Ukrainian Coast        . . . . . . . . . . . . . . . . .       201
                      Yurii D. Shuisky

                      Coastal Morphology and Sea Level Rise Consequences in Tunisia           . . .   211
                      Ameur Oues7ati

                      Responses to the Impacts of Greenhouse- Induced Sea Level Rise on
                      Egypt  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .            225
                      M. El-Raey

                      Impacts of Sea Level Rise on Ports and Other Coastal Development in
                      Algeria   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .           235
                      El-HaFid Tabet-Aou7

                    C. NORTH AND WEST EUROPE      . . . . . . . . . . . . . . . . . . . . . .         239

                      The Vulnerability of European Coastal Lowlands Along the North Sea
                      and Atlantic Coasts to a Rise in Sea Level         . . . . . . . . . . .        241
                      Saskia Je7gersma

                      Impact of a Future Sea Level Rise in the Polish             Baltic Coastal
                      Zone   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .            247
                      Karol Rotnicki and Ryszard K. Borowka

                      Adaptive Options and Implications of Sea Level Rise         in England and
                      Wales  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .            265
                      Ian R. Whittle

                      Policy Analyses of Sea Level Rise in the Netherlands           . . . . . . .    283
                      J.G. De Ronde

                      Impacts of and Responses to Sea Level Rise in Portugal           . . . . . .    293
                      Maria Eugenia S. De Albergaria Moreira

                    D. CENTRAL AND SOUTH AMERICA       . . . . . . . . . . . . . . . . . . . .        309

                      Potential Impacts of Sea Level Rise on the Coast of Brazil            . . .     311
                      Dieter Muehe and Claudio F. Neves





                                                           iv









                 Potential Impacts of Sea Level Rise on the Guiana Coast: Guyana,
                 Surinam, and French Guiana    . . . . . . . . . . . . . . . . . . . .   341
                 J.R.K. Daniel

                 Impacts of Sea Level Rise on the Argentine Coast     . . . . . . . . .  363
                 Enrique J. Schnack, Jorge L. Fasano, Nestor W. Lanfredi
                   and Jorge L. Pousa

                 Regional Implications of Relative Sea Level Rise and Global Climate
                 Change Along the Marine Boundaries of Venezuela   . . . . . . . . . .   385
                 Ruben Aparicio-Castro, Julian Castaneda, and
                  Martha Perdomo

                 Impacts of and Responses to Sea Level Rise in Chile    . . . . . . . .  399
                 Belisario Andrade and Consuelo Castro

                 Living Strategies and Relocation in Latin America    . . . . . . . . .  421
                 Christina Massei

               E. NORTH AMERICA   . . . . . . . . . . . . . . . . . . . . . . . . . .    431

                 Responding to Global Warming Along the U.S. Coast    . . . . . . . .    433
                 James G. Titus

                 Sea Level Rise: Canadian Concern and Strategies      . . . . . . . . .  457
                 K.B. Yuen

                 The Lowlands of the Mexican Gulf Coast    . . . . . . . . . . . . . .   469
                 Mario Arturo Ortiz Perez, Carmen Valverde,
                  Norbert P. Psuty, and Luis M. Mitre

                 Raising Miami -- A Test of Political Will   . . . . . . . . . . . . .   487
                 Ted Miller and William Hyman

                 Accommodating Sea Level      Rise in Developing Water Resource
                 Projects   . . . . . . . . . . . . . . . . . . . . . . . . . . . . .    501
                 Robert H. Schroeder, Jr.
















                                                   v





















                     WEST AFRICA











             ADJUSTMENTS TO THE IMPACT OF SEA LEVEL RISE ALONG
                        THE WEST AND CENTRAL AFRICAN COASTS



                                              A. C. IBE
                   Coordinator, UNEPs Task on Implications of Expected
                  Climatic Changes on the Coastal and Marine Environment
                                   of West and Central Africa
                             Nigerian Institute for Oceanography
                                        and Marine Research
                                 Victoria Island, P.M.B. 12729
                                           Lagos, Nigeria






           ABSTRACT

                The coasts of West and Central Africa, stretching from Mauritania to
           Namibia, are mostly low plain, sandy, surf beaten, and in many places, subsiding.
           The region has population of about 269 million, of which a large percentage live
           along or near the coasts. All but 4 of the 21 countries presently have their
           capital cities on the coast. The lopsided history of urban development in the
           region has meant that most economic and social infrastructures are located in
           these cities. At presefit, erosion and concomitant flooding are prevalent along
           the coasts and have assumed disturbing proportions, putting life and property
           continually at risk.

                These problems would be exacerbated by an accelerated rise in sea level
           that would virtually cripple most economic structures and activities such as
           ports, coastal roads, air fields, rail lines, fishing, farming, oil and mineral
           production, manufacturing, etc. Settlements would be dislocated. Surface and
           groundwater as well as flora and fauna of the region would be profoundly affected
           as a result of increased salinization and added load of sediment and pollutants.
           Increased incidence of heat-related diseases occurring with rising temperatures
           would mean a drastic reduction in the well-being of humans, livestock, and crops.
           The enormity of the various expected impacts dictates that significant measures
           be taken to make the coastal zone habitable. Given the financial disabilities
           of countries in the region, only well-planned anticipatory actions by these
           countries, acting preferably in concert, can help avoid or minimize stress,
           hazards, and resource losses from the expected changes.




                                                   3











              West Africa


              INTRODUCTION

                  Recognizing that the impact of the expected accelerated rise in sea level
              along most low-lying coastlines of the world would lead to a disruption of life
              and dislocation of socioeconomic structures and activities in such places, the
              Ocean and Coastal Areas Programme Activity Center (OCA/PAC) of the United Nations
              Environment Programme (UNEP) set up Task Teams in 1987 to study the implications
              of climate change on the coastal and marine environments of six of the regions
              covered by UNEP's Regional Seas Programme, namely the Mediterranean, Caribbean,
              South Pacific, Southeast Pacific, South Asian Seas, and East Asian Seas regions.
              In 1989, two more Task Teams were assembled for West and Central Africa and
              Eastern Africa. Other Task Teams (for the Black Sea and Kuwait region) are in
              the process of being established. The ultimate objective of these Task Teams
              is to advise governments in the various regions on how to respond appropriately
              to the expected impacts of increased atmospheric temperatures and sea level rise.
              The West and Central African Task Team convened for the first time in Lagos,
              June 7-9, 1989. This paper combines the author's personal views on the problem
              with those expressed by team members during that meeting.


              SETTING

                  The West and Central African (WACAF) region, comprising 21 countries between
              Mauritania and Namibia, stretches approximately for almost 7,000 km between
              latitudes 230 N and 280 S (Figure 1) with a total area of 9 106 W.

                  Climatically (and by implication, in terms of vegetation) the WACAF region
              falls within three main zones (Figure 1):

                  1. North arid zone (semiarid and arid zones);

                  2. Equatorial humid zone (humid and subhumid zone); and

                  3. South arid zone (semiarid and arid zones).


              GEOLOGICAL EVOLUTION AND GEOMORPHOLOGY

                  The evolution of the continental margin of West and Central Africa is linked
              with separation of South American from Africa. The dating of this separation
              is inexact as it consisted of a series of overlapping events.

                  According to Emery et al. (1974), the earliest of the events in the region
              was the development of small basins and troughs (the Liberia and Sierra Leone
              Basins), when North America separated from Africa about 180 million years ago.
              Then followed the separation of South America from Africa, which probably began
              at the south and proceeded northward occupying a time span of about 165 million
              to 135 million years. The general date of separation is indicated by the general
              continuity of Precambrian and Paleozoic strata and structures in Africa and South
              American and the disruption of Jurassic and younger structures. This separation

                                                     4











                                                                                                                                             The











                             1.  Mauritania
                             2.  Cape Verde
                             3.  Senegal                                                     X
                                                                                              %
                         E   4.  Gambia
                             5.  Guinea Bissau
                                                                                 2
                         0   6.  Guinea
                         Z   7.  Sierra Leone                                                      12
                             8.  Liberia                                          4
                                                                                         6 L_..    If '13     A
                                                                                   5

                                                                         Northern            9  10
                             9.  Cote d1voire                             Zone                              14
                             10. Ghana                                                                 15
                             11. Togo                                                                 16    171 1.1          1f
                         .1  12. Benin                                                                                 19
                         0
                         Ig  13. Nigeria                                                     Middle
                             14. Cameroon                                                    Zone
                         w   15. Equatorial Guinea
                             16. Sao Tome and Principe                                                           20
                             17. Gabon

                                                                                                   Southern
                         E   18. Congo                                                               Zone        21
                             19. Zaire
                             20. Angola
                         0
                         Cn  21. Namibia




                 Figure      1. Countries and zones of the WACAF region.


                 led to      the formation of the basins farther south (the Mossamedes, Cuanza, Congo-
                 Cabinda, Gabon, Cameroun, Nigeria, Dahomey, and Ivory Coast Basins). Continued
                 separation of South America from Africa produced easily recognizable ocean-floor
                 provinces (see Emery et al., 1974 for details).

                         The coasts in the West and Central Africa region are mostly low plain,
                 sandy, and surf beaten. Four broad types are recognized: drowned coasts in the
                 northern area; sand bar or lagoon coasts along the north of the Gulf of Guinea;
                 deltas associated with most of the major rivers (e.g., Niger Delta) usually with
                 mangrove swamps and marshes; and coasts with sand spits (and tombolos) formed
                 by accumulation of longshore transported sand in bays found in the southern
                 parts of Angola.

                         From the point of view of their geological evolution and present
                 geomorphology, the coasts in the region are clearly vulnerable to sea level rise,
                 not only because they are low-lying but also because the sedimentary basins that
                 dominate the coasts are areas of subsidence. These basins, formed by the rapid
                 deposition of sediments in a tectonic setting, are even in present times, still
                 undergoing dewatering and compaction. In recent times, human intervention by

                                                                                 5










             West Africa

             fluid extraction (including oil and gas) in the coastal zone has had the effect
             of accelerating the subsidence due to natural causes.


             SOCIOECONONIC SETTING

             Settlement and Population

                  The WACAF region has a population of about 269 million and with a rapid
             annual growth rate of about 2.9%, the population will most probably double itself
             within the next two and a half decades.

                  Due to the history of early contracts with Europeans, most important cities
             in the region are located on the coast. Of the 21 countries, only 4 do not have
             their capital cities in the coastal area. These coastal cities are nearly always
             synonymous with centers of commerce, industry, and politics and have thus
             attracted very large populations. For example, Lagos (Nigeria) is reputed to
             have a population of over 8 million out of an estimated national population of
             100 million. The story is much the same for Dakar, Abidjan, Freetown, Banjul,
             etc.

             Communication

                  Ports and harbors as transportation access facilities for maritime
             activities provide the lifeline for socioeconomic development of the region and
             are all located in the coastal zone. Most of these ports and harbors are linked
             by intricate road, rail, and air transport routes that complete the network for
             the export-import trade that is the linchpin of most economies in the region.
             Coastal roads, some of which are presently under threat from marine erosion,
             provide particularly easy access between the countries in the region, while air
             transport offers a means of rapid movement of goods and peoples between the
             countries.

             Industries

                  When compared with Europe or America, the West and Central African region
             is poorly industrialized, but the pertinent issue is that the industries that
             do exist are concentrated mainly on or near the coast, most often around the
             capital cities. Such industries include mining, oil and gas, petroleum products,
             textiles, paper and pulp, timber, brewing, pharmaceuticals, plastics, leather,
             lumbering, and various manufacturing outfits.

             Agriculture

                  Agriculture is the most important industry in the West and Central African
             zone.  About 70 to 80% of the population is engaged in agriculture, and the
             economies of most countries in the region depend on it. The coastal areas are
             becoming increasingly important to this industry and have the potential of
             increasing substantially their contribution to agricultural production. About
             60 to 80% of the food production of this zone comes from small farms.

                                                      6











                                                                                          The

               The crops and produce from agriculture of this zone may be classified as
           follows (UNEP, 1984):

               1.  Tree and horticultural crops (oil palm, coconut, citrus, avocado, pear,
                   rubber, kolanuts, sheanut, cocoa, coffee, pawpaw, banana, plantain,
                   mango, pineapple);

               2.  Cereals (maize, rice, sorghum, millet);

               3.  Root crops (cassava, cocoyam, yam, sweet potato, ginger, tigernut);

               4.  Vegetables and beans (groundnuts, cowpea, phaseolus bean, melons); and

               5.  Other crops (sugarcane, tobacco, and cotton).

               Apart from crops, the coastal and forest areas have a low livestock
           population.  The main categories of livestock are large ruminants (cattle and
           camels), small ruminants (sheep and goats), equines (asses, mules, and horses),
           pigs, and chicken. The distribution of livestock is uneven. It is governed by
           natural factors such as the presence of tse-tse fly and historical and cultural
           factors as well as vegetation types.

               Mariculture and aquaculture are becoming increasingly popular in the coastal
           zone of the West and Central African region. Captive breeding of economically
           important species such as Chrysicthy spp., Megalops spp., Clarias lazera, as well
           as oyster culture, are widely practiced in Nigeria and Ghana with varying degrees
           of success. In Angola, the culture of mussels, Perna Derna, is popular.


           NATURAL RESOURCES

           Forestry and Wildlife

               The West and Central Africa region is the home of the tropical rain forest
           and mangroves of great biological diversity, but the density and variation of
           the forests are greatly influenced by climate, especially rainfall. The rain
           forests and mangroves form the basis of an extensive lumbering industry.

               The region is rich in wildlife, which is an important source of protein
           and are hunted intensively, but several species are on the endangered list as
           a result of uncontrolled harvesting and poor management.      The most important
           wildlife include elephants, lions, buffalos, hartebeests, smaller antelopes of
           different kinds, warthogs, aardvarks, civet, cats, chimpanzees, baboons, birds
           of all types, and reptiles.

               The animal species found in the mangroves are also found in other brackish
           water, salted waters, and nearby forests. The fauna consist of invertebrates,
           molluscs, crabs, prawns, and fish, reptiles, birds (e.g., herons, storks, and
           ibises), reptiles, and mammals (monkeys, bush pigs, and manatees). Most of the
           reptiles, birds, and mammals are semi-aquatic.

                                                   7










             West Africa

                  In addition, the mangroves provide important spawning and breeding grounds
             for a variety of finfish and shellfish that are the targets of artisanal and
             industrial fishery in the coastal zone.

             Fisheries

                  Despite deficient statistics, several resource surveys in the different
             countries of the region show that respectable quantities of fish are harvested
             in the region. According to UNEP (1984), production figures show high harvests
             in Angola, Cameroon, Ghana, Ivory Coast, Nigeria, Namibia, Senegal, Sierra Leone,
             and Zaire. Namibia, with 761,000 metric tons in 1978, has the highest figures.

                  The existence of upwelling zones in the region (both permanent and seasonal)
             is known to be the basis of the rich fishery of the region.      Major permanent
             upwelling zones occur near Mauritania and Senegal as well as off the Congo,
             Angola, and Namibia, whereas seasonal upwelling occurs in the Gulf of Guinea
             between Cote d'Ivoire and Nigeria.    The lagoons, creeks, and bays along the
             coasts are also areas of high productivity.

                  Fish and shrimp are the major resources of the region, although in some
             countries such as Senegal, Sierra Leone, Nigeria, and others, edible molluscs
             from near-shore areas are harvested in considerable quantity.       The shrimps,
             prawns, and oysters are now the targets of export trade in the region.

             Minerals (Including Oil and Gas)

                  A variety of minerals ranging from commonplace sand and gravel to gold,
             diamonds, and petroleum are mined from the coastal zone of this region.
             According to UNEP (1984), the extent of mined resources, particularly if revenues
             from petroleum products are considered as part of this grouping, is significant
             in countries such as Nigeria, Gabon, Liberia, Guinea, Angola, and Sierra Leone;
             their economies are best described as mineral economies. For example, the export
             of petroleum accounts for over 90% of the export and foreign exchange earnings
             of Nigeria. Except for Gabon and Nigeria, nonfuel minerals still dominate the
             economies of the other countries listed above.

             Water Resources

                  The West and Central African region is well-endowed in terms of rivers.
             It is also blessed with heavy precipitation (reaching 2,000 mm in the south),
             which means that the recharge potential of groundwater aquifers is very high.
             Water balance maps depict areas of high rainfall, high humidity, and low
             temperature, i.e., Liberia, Sierra Leone, and southeastern Nigeria, which have
             the greatest water surplus (amounting to the equivalent of more than 1,000 mm
             of rainfall).   In the more arid conditions of the north, however, rainfall
             decreases to 50 mm and, under such circumstances, aquifer recharge is very low.





                                                    8










                                                                                                    The


             PRESENT CLIMATE EFFECTS

                  The West and Central African coasts are the scenes of high wave intensity.
             This fact, along with other adverse geological conditions (e.g., erodibility of
             sediments, subsidence), and detrimental human interference in the natural
             environment, have meant that erosion and concomitant flooding are prevalent along
             the coasts of the region (Ibe and Quelennec, 1989). In some places, the flood
             rates are so rapid that whole towns (e.g., Grand Popo in the Benin Republic and
             Keta in Ghana) have virtually disappeared.         Elsewhere, life and property have
             been put to risk with resultant economic losses and social misery.

                  The region in recent times has witnessed a prolonged scourge of drought
             and desertification with all its attendant dislocation of population and
             destabilization of socioeconomic activities. Hunger and disease have afflicted
             the populace as a result of crop failures and losses in livestock.


             PREDICTED CLIMATE CHANGES

                  Different scenarios of climate change have been put forward and defended
             by various authors, but the Task Team adopted as the basis for its deliberations
             the assumptions accepted at the UNEP/ICSU/WMO International Conference in
             Villach, October 9-15, 1985, i.e., increased temperature of 1.5-4.5% and sea
             level rise of 20-140 cm before the end of the 21st century.            (For the purpose
             of the meeting, temperature elevation of 1.5* and sea level rise of 20 cm by the
             year 2025 were accepted with the understanding that these estimates may have to
             be revised on the basis of new scientific evidence.)


             IMPACTS FROM EXPECTED CLIMATIC CHANGES

                  The problems of erosion and flooding presently experienced along the coasts
             of the region will be exacerbated by the predicted acceleration in global sea
             level rise.    In fact, worldwide evidence points to erratic jumps in the rates
             of shorel i ne retreat that suggest sea 1 evel ri se as a contri butory f actor (Pi 1 key
             et al., 1981). Although the accepted predicted values may seem small, its impact
             along the low-lying and, in many cases, subsiding coasts in the region would be
             immense, particularly when viewed from point of view of the Bruun (1962) rule,
             which predicts that a rise of 0.3 m (1 ft) of sea level will cause a shoreline
             recession of more than 30 m (100 ft) on low-lying coasts. Subsidence phenomenon,
             known to be active in major coastal sedimentary basins in the region, would
             aggravate the situation.

                  With the increase in ocean temperature, tropical storms are likely to extend
             into some humid areas, and with rising sea level, the periodic flooding presently
             being experienced in vast coastal areas will become more frequent and
             devastating. This will virtually cripple most economic structures and activities
             in the densely populated and highly urbanized settlements proximal to the sea.
             Ports, coastal roads, and rail lines will be knocked out of action; fishing,


                                                         9










             West Africa

             farming, oil and mineral production, and manufacturing will be interrupted;
             people and businesses will be forced to relocate, etc.

                 As a result of increased sea level rise, surface drinking water and
             groundwater aquifers would be rendered unusable as sources of potable and
             irrigation water because of increased salinization and added loads of sediment
             and pollutants.

                 The fragile ecosystems of the coastal zone will be adversely affected by
             inundation from the sea and may not be able to perform their traditional roles
             as the spawning and breeding grounds of most finfish and shell fish that are the
             targets of artisanal and inshore industrial fishermen.

                 A rise in sea level will also profoundly affect the flora and fauna of the
             region as well as the agriculture and livestock production. Vegetation kill due
             to salinity stress would result, as is presently being witnessed in the Mahin
             area on the northwestern flank of the Niger Delta (Ibe, 1988a,b).             The
             distribution and composition of the coastal vegetation would be affected with
             salt-loving species increasing. This may decrease suitable forage for livestock,
             resulting in a depression of this occupation among coastal populations.       The
             areas of saline soils would increase, making them unsuitable for cultivation of
             crops like maize, banana, pineapple, etc. Coastal plantations would also suffer
             from salinization. Hunger, already a problem in the region, would worsen.

                 Apart from the impacts due to sea level rise, othei, impacts derived from
             a rise in temperature would result.    Increased humidity and temperature would
             favor rapid multiplication of insects such as mosquitoes and the tse-tse fly,
             resulting in diseases such as malaria and trypanosomiasis reaching epidemic
             proportions. Temperature-sensitive plant diseases and weeds would also increase
             and cause greater damage to crops. Increased incidence of heat-related diseases
             with rising temperatures would mean a reduction in the well-being of humans and
             livestock. The general level of discomfort and misery would be high.


             ADJUSTMENTS TO IMPACT OF SEA LEVEL RISE AND OTHER EFFECTS DUE TO CLIMATE CHANGES

                 It is imperative that countries in the region make some adjustments to cope
             with the adverse conditions that would accompany the rise in sea level and higher
             atmospheric temperatures. Given the financial disabilities of countries in the
             region in the face of these serious threats, well-planned anticipatory and, in
             some cases, reactive (including adaptive) actions need to be pursued by the
             countries acting individually or in concert to avoid or minimize the stress;
             hazards and resource losses would be likely to occur with the expected changes.

                 In relation to sea level rise, there will be a need to protect heavily
             built-up areas having high-value installations where the option of relocation
             is not a reasonable economic proposition.    But while many of the engineering
             countermeasures are feasible for shoreline protection in the face of sea level
             rise, they are economically impractical in view of the financial position of most


                                                    10










                                                                                          The

           countries in the region.    The approach here should be toward the adoption of
           low-cost, low-technology, but effective measures such as permeable nonconcrete
           floating breakwaters, artificial raising of beach elevations, installation of
           rip raps, timber groins, etc., from locally available materials. Fortunately,
           outside the urbanized centers, the coasts are almost in pristine condition and
           largely uninhabited except perhaps for small fishing settlements which, in any
           case, are highly mobile.       In such situations, resettlement of existing
           populations and the enforcement of set-back lines for any new developments on
           the coast should be applied. Where coasts are deemed highly vulnerable, total
           ban of new development is necessary.

                Designs of new buildings and other facilities should take into account the
           predicted and continuing rise in sea level as well as increased heat.          For
           instance, houses should be concerned with increased use of natural ventilation
           modes. Afforestation of coastal lands would provide some measure of damping of
           wave energy as well as relief from increased heat.

                Other adjustments would involve the protection of arable land, improved
           management of water resources, introduction of new agrotechnology to cope with
           new realities, controlled land use policies, maintenance of food reserves, and
           the introduction of emergency disaster relief measures.

                For protecting arable lands, some of the low-cost, low-technology measures
           mentioned above would be applicable. Improved water management techniques would
           involve the building of dams (after environmental impact assessment), aqueducts,
           reservoirs, irrigation systems, and river diversions with the objective of
           husbanding water in times of drought. The adoption of new agrotechnology should
           aim at introducing more salt- and heat-tolerant crops, developing adaptive
           irrigation systems aimed at reducing salinity stress, and so on. Although the
           region is far from being self-sufficient in its food needs at present, there will
           be a need to stockpile food and institutionalize other disaster relief measures
           to cope with emergencies that may arise from sudden flooding or drought.

                Other adjustments would require the setting up of environmental monitoring
           and early warning systems, providing flood vulnerability and land use maps for
           coastal areas, and perhaps above all, providing public information and education.
           This calls for extensive information-gathering, analysis, and utilization.
           Public information and education would drive home to the populace the seriousness
           of the anticipated impacts from increased atmospheric temperatures and sea level
           rise and thus better prepare them for the implementation of certain protective,
           preventive, or adaptive measures that would necessarily have to be put in place.


           CONCLUSION

                Higher atmospheric temperatures and increased sea level rise are realities
           that humanity has to cope with now and in the future.      Even if all suggested
           measures to stop the introduction of greenhouse gases were put in place now, the
           world would still experience many of the anticipated impacts due to "sins of
           omission or commission" already committed by man toward global warming.

                                                   11









               West Africa

                    The application of most of the protective, preventive, or adaptive measures
               suggested above will be imperative but it is important that proposals for
               adjustments to the expected impacts be embodied in a coordinated and enforceable
               regional development plan.      UNEP's Regional Seas Programme for the West and
               Central African region affords a vantage platform for discussing and
               institutionalizing such a plan.      It is hoped that governments in the region,
               while pursuing policy options at the national level, would now appreciate, even
               more than ever before, the distinct advantages for a regional approach to the
               problems associated with global warming.


               ACKNOWLEDGMENTS

                    The author acknowledges the help of Profs. 0. Ojo, 1. Findlay and A. Asare,
               and Drs. T. 0. Ajayi, S. Zabi, I. Sy-Niang, S. Ogbuagu, T. Egunjobi, L. Awosika,
               M. Akle, and G. Nai who are members of the WACAF Task Team.         Miss S. A. Fakan
               typed the manuscript.


               BIBLIOGRAPHY

               Bruun, P. 1962. Sea level rise as a cause of shoreline erosion. Am. Soc. Civil
               Eng., Proc. V.88 Waterways and Harbours Div. Journ. WW1:117-130.

               Emery, K.O., E. Uchupi, J. Phillips, C. Bowin, and J. Mascle.             1974.     The
               Continental Margin of Western Africa: Angola to Sierra Leone. Contribution No.
               3481. Woods Hole, MA: Woods Hole Oceanographic Institution.

               lbe, A.C.    1988a.   The Niger Delta and the global rise in sea level.             In:
               Proceeding of the   SCOPE Workshop on Sea Level Rise and Subsiding Coastal Areas,
               Bangkok, Thailand, November 7-14,, 1988. Pergamon Press.

               Ibe, A.C.    1988b.   Coastline Erosion in Nigeria.        Ibadan, Nigeria:      Ibadan
               University Press, 217 p.

               Ibe, A.C., and R.E. Quelennec.      1989.  Methodology for assessment and control
               of Coastal Erosion in the West and Central African Region. UNEP Regional Seas
               and Reports and Studies No. 107. Geneva: United Nations Environment Programme,
               112 P.

               Pilkey, O.H., et al. 1981. Old solutions fail to solve beach problem. Geotimes
               26:18-22.

               UNEP.    1984.  Environmental management problems in resource utilization and
               survey of resources in the West and Central African Region UNEP Regional Reports
               and Studies No. 30. Geneva: United Nations Environment Programme, 83 p.






                                                         12










            THE GULF OF BENIN: IMPLICATIONS OF SEA LEVEL RISE
                                    FOR TOGO AND BENIN


                                         KOLAWOLE S. ADAM
                                 Universite Nationale du Benin
                                          Cotonou, Benin






           INTRODUCTION

               The coastline of west Africa in general, and the Gulf of Benin in
           particular, has witnessed sea level variations of great dimensions in the past.
           The present configuration of the coast is the product of the oscillation of sea
           level that took place 20,000 years ago. Short-term as well as seasonal oceanic
           fluctuations (tides, waves, storm waves) linked to atmospheric disturbances are
           sometimes spectacular on the West African coasts, but the greatest dangers are
           long-term changes that could result from a change in the world's climate. Global
           warming is probably the cause of the rise in sea level that we have been
           witnessing since the beginning of the 20th century.

               Accelerated sea level rise -- which is already 2 cm per year along some
           coasts -- will bring about important natural, socioeconomic, and cultural
           disruptions in the coastal-plain of the Gulf of Benin. The coastal areas are the
           most densely populated and contain the economic heart of both Benin and Togo,
           including the main towns, the port and airport infrastructure, and the majority
           of the countries' industries.

               The coast of the Gulf of Benin is a low and even coastal plain stretching
           nearly' 500 km from the Cape of the Three Headlands (Takoradi Region in Ghana) to
           the Delta of Niger (Nigeria). This paper focuses on the approximately 175 km
           that constitute the coastal zone of Benin and Togo, examining (1) the possible
           effects of future sea level rise on the coastal ecosystems such as deltas,
           estuaries, lagoons, mangroves, and human activities of the coastal plain; (2)
           the reactions of the different research institutes and decision-makers in the
           face of these impacts; and (3) the present characteristics of the coastal
           environment.



           IMPACTS OF ACCELERATED SEA LEVEL RISE

               Rising sea level is always accompanied by inundation and erosion. The Gulf
           of Benin coast will be very sensitive and catastrophes may result if appropriate

                                                  13











             West Africa

             precautions are not taken in time. We discuss the effects and damages of three
             possible scenarios:

             Sea Level Rise of 50 cm

                  As Figure I shows, the shore could retreat considerably, particularly
             between Anecho and Grand-Popo. A retreat of about 100 meters may be foreseen,
             which will be a big blow to the Cotonou-Lome interstate road, which would be
             dangerously threatened and would have to be moved inland.         Nearly half the
             beaches and coconut-tree plantations would disappear in this region, although
             some of the agriculture would not suffer serious damage. We can be certain that
             Grand-Popo and Agoue graveyards would be periodically washed by the waves.

                  If urbanization is checked, particularly in the east of Cotonou, the risks
             would be less, but there is little hope that this will happen. The swampy areas
             would increase considerably, especially in the estuary of the Mono River, which
             would bring about a loss of nearly 25% of the existing upland, especially in the
             city of Cotonou where the situation is already highly critical. The ecological
             imbalance caused by the oversalinization of the coastal lagoons would surely be
             disturbed; the degradation of the mangroves which was already persistent will be
             aggravated.

                  Protective measures would continue to aggravate the problems downstream, but
             they can protect the very sensitive strategic places on the coast. However, the
             protection would be short-lived and would lead to other management problems.

             Sea Level Rise of 100 cm

                  All the damages from the previous scenario would be aggravated. The retreat
             of the shoreline would provoke the displacement of all hamlets built on the crest
             of recently formed barrier islands. Two-thirds of the town of Cotonou would be
             submerged and the town would be depopulated since there is no possibility of
             extension; by contrast, the town of Lome could be stretched farther north on the
             plateau.  The towns of Grand Popo, Agoue, Aneho and Kpeme would be seriously
             threatened and may disappear. A high salinization of the coastal plain would
             render life conditions more precarious.       Protective measures would not be
             feasible, and people would instead think of controlling the migration toward the
             plateau.

             Sea Level Rise of 200 cm

                  Because their elevations are only 3 m, all recently formed barrier islands
             will come close to complete submergence; the portions not inundated will almost
             surely erode (cf. Figure 2). Only a few small "islets" of lesser importance
             will remain. All human settlements of the coastal plain wwould disappear. Only
             the part of the town of Lome on the plateau would be able to resist destruction.
             The Lome -Cotonou -Lagos interstate road would be partly submerged. The settlement
             patterns in this part of the world would have to be reconsidered.    In any case,
             if this rise of the sea level persisted, people would surely not wait before
             considering relocation toward the plateau and new modes of life.

                                                    14

















                                                                                                                                            COME
                                                                                                                                                                                                      GOOOMEY


                                                                                                                                                                     OMAN

                                                                               G     0




                                                                                                                                   GRA O-POPO



                                                                                                 NO

                                                                              KPEME


                                                                                                A T L A N T I                 c                      0 c      E     A    N





                                Figure 1. Areas vulnerable to a 50 to 100 cm rise in sea                                                                      level.








                                                                                                                                            COME
                                                                                                                                                                                                      G

                                                                                                                                                                     OUtDAK

                                                                    T     0     G    0







                                                                IA. '10..
                                                                                               "ENO

                                                                              KPE.F


                                                                                                A T     L    A   N    T   I   C                      0    C    E    A    N

                                             ME
                                                P-1


                                Figure 2. Land loss from a 2-meter rise in sea level.










             West Africa

             POSSIBLE RESPONSES TO SEA LEVEL RISE

                 There are two solutions to safeguard the coastal zones of Togo and Benin
             along the Gulf of Benin:  (1) coastal defense and the artificial nourishment of
             the beaches; and (2) respect for the littoral dynamics which requires avoiding,
             as much as possible, development that sets up an unavoidable confrontation
             between humanity and the sea.

                 The evolution of research in the region appears to support a gradual shift
             from the former to the latter approach.    Still, most proposals for addressing
             erosion are short-term and do not consider sea level rise. The overall theme of
             most proposals is a natural protection of the littoral zone by using beach rock.
             But the characteristics of the Gulf of Benin coast suggest that the effectiveness
             of this natural protection would be limited, particularly if sea level rise
             accelerates.

                 In both Togo and Benin, survey offices and university Applied Research
             Laboratories are responsible for management of this coast. The labs are studying
             the possibilities of safeguarding nature according to its evolution from the
             field and the laboratory's research.      The survey offices are studying the
             cheapest methods of protecting certain elements of the environment by fighting
             against some natural forces.

                 Given the prohibitive costs of some solutions and the lack of resources in
             these difficult times, the majority favor measures that control the littoral
             dynamics.   The authority of the researchers is limited because it is the
             decisionmakers who have the final word. Sometimes, they neglect the advice of
             the nationals and turn to proposals made by foreign survey offices. But policies
             are changing. Public opinion is obliging decisionmakers to enter into dialogue
             with researchers, planners, and town developers. Nowadays, few people perceive
             the rise of the sea level as an important factor in the management of the coastal
             zone. But over time, the various scientific and policy reports on the subject
             will probably be able to convey the importance of such a phenomenon.


             THE COASTAL ENVIRONMENT OF BENIN AND TOGO

                 On the coasts of the Gulf of Benin, the tide is semidiurnal, with two highs
             and two lows of nearly equal amplitudes that succeed each other at regular
             intervals.   The spring and neap tidal ranges are 1.6 and 0.6 meters,
             respectively.

                 Along the shores of Benin and Togo is a coastal strip whose width increases
             from the west (2 km in Lome) to the east (10 km at the Benin-Nigerian border).
             It is a contact zone between many old and new barrier islands, lagoons, and
             swamps that separate the coastal features from the inland slopes (yellow and
             claylike sands). This body is limited in the north by a scarp of the red-clayed
             plateau. There are numerous barrier islands with elevations of 3 to 5 meters.



                                                    16











                                                                              Adam

                               Table 1. Evolution of the Coast


               SECTORS           t959-64 1964-69 1969-75 1975-81 1981-84 1984-89


          ESTUAIRE VOLTA-KETA                -        -        -       -        -


          ZONE W KETA               +        +        +        +       +        +

          KETA VILLE-AFLAO                                                      -    I
          W PORT -LOME                         +      +        +       +        +

          EST PORT -LOME


          TROPICANA


          TROPICANA - KPOGAN


          KPOGAN-AGBODRAFO


          AGBODRAFO- GUMUKOPE


          GUMUKOPE- ANEHO


          ANEHO-HILLA-KONDJ


          HILLA-KONDJI -GRAND POPO


          GRAND POPO VILLE                                             +        +


          GRAND POPO - OUIDAH


          OUIDAH - AEROPORT- COTONOU


          W- PORT - COTONOU                  +        +        +

          PORT - P. L. M.                    +               +       +


          P. L. M. - SO BE PRIM


          SO BE PRIM KLAKE
                                I                 I        I




                       +     FATTENING


                             EROSION


                             STABILITY


                             APPARITION OF THE BEACH ROCK


                             EFFICIENT BEACH - ROCK


                                             17










             West Africa

                  The evolution of the coast has been schematized in Table 1. The offshore
             barrier islands are mainly occupied by a well-planned planting of coconut trees
             complemented in the east by the planting of eucalyptus and filao. Mangroves are
             mainly found along the coastal lagoons, with the western boundary schematized by
             an Aneho-Glidji line.


             HUMAN ACTIVITIES ALONG THE GULF OF BENIN

                  Since the 16th century, the littoral of the Gulf of Benin, just like the
             whole of the West African coast, has been the center of many human migrations and
             the magnet for intense agricultural and commercial activities.

             Demography

                  Although the distribution of the population is uneven, the density of the
             rural population in the coastal plain of the Gulf of Benin is more than 200
             inhabitants per square kilometer. The urban and demographic dynamism is marked
             by industrial and related activities in Cotonou and Lome.            The combined
             population of the major cities (Lome, Aneho, Grand-Popo, Ouidah, Cotonou, and
             Seme) is estimated at about 1.5 million inhabitants; the population  of the entire
             coastal plain is about 2 million, about 25% of the total population of both
             countries. The urban dynamism of Cotonou is of concern, as it is a town in full
             demographic explosion (600,000 persons) where the only open space for expansion
             is on barrier islands stretching east of the town where erosion is already very
             serious.

             Economic Activities

                  The coastal region is the economic hub of both countries, for it harbors the
             main towns, the portsL and airports, and, above all, a number of important
             industries. The role of the port activities in the present economic development
             of those countries is unquestioned (despite the scarcity of comparative data to
             demonstrate its importance). Lome and Cotonou ports play an important role in
             the import and export trading of landlocked countries of West Africa (Mali,
             Burkina Faso, and Niger). The steady growth in the port activities, which was
             more than 500% from 1968 to 1978, even recorded a sudden increase between 1977
             and 1980 because of the onset of certain activities (oil refinery in Lome and the
             role played by Nigerian imports during the time of the oil boom, when Lagos Port
             was "congested").

             Agriculture

                  Agriculture in this region is a function of the climatic and pedologic
             conditions, which are not very good.     The bars are mainly occupied by well-
             arranged plantations of coconut trees.     Near the coastal lagoons, some grain
             foodcrops are grown (maize, cassava, cowpeas) as well as vegetables.




                                                     18











                                                                                         Adam

           Fishing

                Just like the Lebou in Senegal, the Akan in Cote d'Ivoire and in Ghana, the
           Peda and the Pla peoples from Ghana have moved into the coastal strip of the Gulf
           of Benin, practicing a flourishing fishing economy which nurtured the big trade
           with the people of the interior. It was mainly the lagoons that attracted the
           Peda, even though Lake Nokoue and Porto-Novo lagoon are largely exploited by the
           Tofinu. In general, fishing is a traditional activity (small day-trip fishing)
           that provides freshwater species (tilapia and crustacea).

                Since 1960, with the construction of Lome and Cotonou ports, offshore
           fishing has developed with the massive arrival of Ghanaians (Fanti and Keta) who
           introduced gear boats in this business that became semi-industrial . The economic
           position of fishing in the region is in an average position (66th) in the world,
           near the Cote d'Ivoire and far behind Nigeria (28th), Senegal (33rd) and Ghana
           (34th).

                Today, offshore fishing is the most important activity practiced by
           fishermen living at the coast; it provides a considerable quantity of fish (about
           50 million tons/year for both countries) to a large part of the population of the
           capital cities and the coastal towns.

                Many of the fish caught in the region depend upon coastal wetlands.
           Accordingly, the loss of those areas to rising sea level could severely hurt
           fishing. The ability of the shallow water bodies that replace the wetlands to
           support fisheries is unknown.

           Modifications of the Shore

                The demands of the national economy have called for the construction of two
           deepwater ports in Lome and Cotonou. The protecting jetties of these ports are
           large and they have accelerated the process of coastal erosion already started
           by the construction of Akossombo Dam. More recently, the construction of many
           piers for the protection of some strategic zone (Kpeme factory, Aneho town, P.
           L. M. Hotel, Hotel da Silva) and the hydroelectric developments on the Mono River
           (Nangbeto Dam) have added to the sedimentary and ecological inbalance of the
           coastal zone (see Table 1).

           Coastal Management

                The general consumption of space all along the Gulf of Benin by hotels and
           various structures and equipment aiming at the tourist trade is presently a
           fundamental concern of planners and developers. In light of today's disorderly
           management, avoiding irreversible choices will require a new policy for the
           coastal zone. For the past 10 years, a planned development scheme has been under
           consideration which, taking into account the present land uses, can be summarized
           as follows:





                                                   19










            West Africa

                 -   to limit the coastwise boundary of the urbanization zones and main
                     development;
                 -   to define the mode of stabilization of the coasts; and
                 -   to plan the zones for recreation and tourism exclusively equipped with
                     mobile facilities.

                 Up to now, no government decree has considered such ideas; so, for the time
            being, they remain purely and simply academic reflections.


            CONCLUSION

                 The fragility of the coasts in general and of those of West Africa in
            particular is of great concern. To try to best preserve this littoral, it is
            necessary to understand its dynamics better. Sea level rise is an inescapable
            parameter to reckon with in any approach to the management of the littoral. A
            systematic inventory of all useful information sources is a foremost task (e.g.,
            topographic maps, general maps, inventory maps, aerial photographs, satellite
            pictures, oceanographic data, population density maps, historical documents).
            Certain approaches such as satellite teledetection are indispensable tools today
            to better understand certain phenomena (e.g., waves, salinity, currents, water
            temperatures, biological processes of estuaries). All of these elements are the
            basis for understanding and efficiently managing the coastal heritage.


























                                                   20











                                                                                                Adam

                                                   APPENDIX

                    THE GENERAL CHARACTERISTICS OF THE LITTORAL OF THE GULF OF BENIN



            THE NATURAL SETTING

            The Coastal Climate

                  The climate of the Gulf of Benin is of a beninian type (subequatorial) with
            two rainy seasons (mid-March/July and September/November) and two dry seasons.
            The average rainfall is 1,200 mm per year decreasing toward the west (1,400 mm
            per year in Seme and 850 mm per year in Lome); this decrease is due to the
            configuration of the coast in relation to the marine winds. The temperature is
            constantly high (yearly average is 27*C) with the average maximum in March (330C)
            and the average minimum in August (250C) when temperature can go down to 22.50C.
            The months of January, February, and March record h i gh thermal ampl i tudes (120 C) .
            These variations are reduced during the rainy season.

                  The predominant direction of the wind is southwest with average speeds of
            4 to 6 m/s (3 Beaufort).       The winds from the south-southeast sector are not
            frequent and they blow in April and May. Because of the relatively even relief,
            the pattern of winds does not vary much according to seasons. In dry season, the
            wind strength is weak to moderate (2 to 5 m/s) in the morning. It is stronger
            during the day (5 to 7 m/s) and becomes moderate in the evening and in the night
            (4 to 6 m/s) . Duri ng the rai ny season, a moderate wi nd bl ows (4 to 6 m/s) i n the
            morning which becomes stronger in the afternoon (6 to 8 m/s)               and remains
            constantly moderate to strong (5 to 8 m/s) in the evening and at night. The peak
            speeds are reached during the passage of rain lines (east to west direction) with
            average speed of 15 m/s, accompanied by harsh winds and rainstorms.

            Swells and Waves

                  Along the Gulf of Benin, one observes a long swell of a distant origin, the
            wavelength of which can vary between 160 and 220 m. This swell unfurls over the
            bar at a distance of about 150 to 200 m from the shore (characteristics at the
            Cotonou wharf). There are also waves due to local winds whose characteristics
            are changing but have little importance for the morphological phenomena of the
            coast.   Their wavelength is about 50 m.       The swell whose primary period is 12
            seconds (even though it can sometimes vary between 10 and 16 seconds) has a
            relatively regular average height between 1.0 and 2.0 m.

                  Table 1 gives the average amplitude of swell in Cotonou. Using the averages
            observed in Lome in 1955 and 1961, it is noted that swells are stronger in
            Cotonou than in Lome by 28% in 1955 and 11% in 1961.          This difference is due,
            according to Sitarz (1963), to the protection offered by Cape St. Paul (Ghana)
            to Lome port area.

                  These swells generally travel from southwest to northeast (1980). The most
            recent surveys give the following distribution:

                                                       21











              West Africa


                        SE     S                      135* to 180*        = 10%
                        S      SW                     180* to 203*        = 36%
                        S      SSW                    2030 to 2250        = 54%

                    The breaker line in the region    of Cotonou occurs   at a depth of 3 m, or at
              about 150 to 200 m from the shore:      This is the locus   of important sedimentary
              movements.

              The Coastal Geomorphology

                    The geomorphological evolution has mainly resulted    from the fluctuations of
              the marine level during the Quaternary, and secondly by the local tectonics
              (faults of Togbin, of Godomey and Krake determined by       J. Land and G. Paradis,
              1977). Since 5,000 years ago the series of barrier features have regularized a
              coastline that was indented with deep Has during the Flandrian transgressive
              maximum.    These are essentially sandy bars; granulometric and microscopic
              analyses confirm the marine origin of these sands.

                    One  can   subdivide this shore into three            sections with     varying
              characteristics:

              Lome to Grand-Popo

                    A narrow coast (average width = 1 km and narrows towards the east) with
              altitudes of between 3 and 5 m. Three types of profiles can be distinguished
              according to hydrodynamic parameters:

                    0   Profile with straight crest, steep seaward slope, short foreshore (less
                        than 3 m), upper berm at 1 m, even surfaced slope: profile resulting
                        from strong swells.

                    0   Profile of very strong swells:     profile with round crest, with basal
                        berm on its seaward slope. The inlandside of the barrier is steeply
                        sloped toward the lagoon.

                    4   The beach profile with straight or rounded crest characterizes the
                        transition between a strong swell and an average one.

              Grand-Popo to Godomey

                    The altitudes of the barriers in this section also vary between 3 and 5 m,
              and they are modified on the inland margin by the lower course and the mouth of
              River Mono, the coastal lagoons, and the swamps. The width of the bars is quite
              narrow (less than 200 m). We see the same types of profiles as in the previous
              case.


              Godomey to Krake

                    The bars break up into a multitude of successive parabolic crests which are
              rigorously parallel, of west-east orientation, and of a maximum altitude of 6 m.

                                                       22











                                                                                         Adam

           The granulometric (medium and fine sands) and morphoscopic (blunted and shining
           sands) measures are in favor of a marine origin. These fine sands, generally
           well sorted, have been deposited under homogeneous hydrodynamic conditions even
           though some local disturbances can be noticed.

                Close analysis of sediments along the littoral of    the Gulf of Benin shows
           fine to coarse sands (median diameters between 0.4 and    I mm) at the foreshore,
           up to 4 m; from 4 m to 16 m elevation, the sediments      are very fine and well
           sorted. Despite the homogeneity in the distribution of    sediments from the west
           to the east of the gulf, there is a strong variation to the east of the mouth of
           River Mono; these sediments have medium diameters from    3 to 6 mm in the depths
           of -12 m, and they are composed of coarse sands mixed with gravel.

                The geomorphological cartography carried out with the collaboration of
           researchers of both universities (Adam, 1986) has made it possible to demonstrate
           the complexity of the evolution of this coastal strip. One element is durable
           formation, beachrock, evidence of an old beach consolidated by a carbonate
           cement. This formation is made of overlying slabs whose thickness varies between
           0.5 and 1.5 m and whose width varies between 25 and 50 m. Its position in the
           littoral profile (sometimes reaching + 3 m altitude) and its mechanical
           resistance causes beachrock to be a natural protection against coastal erosion.
           It presently plays a role of wave-breaker, eliminating the actions of the swell
           in the coast of the eastern part of Lome. This formation exists all along the
           coast at different altitudes.   Its role seems to be efficient under the present
           hydrological conditions prevailing between Lome and Kperme, between Ouidah and
           Cotonou, and to the east of Seme. Its efficiency is null elsewhere. Today, the
           distribution of beachrock is to be considered in any survey aiming at evaluating
           the littoral of the Gulf of Benin.

           Inlets

                Three hydrological systems present themselves from the west to the east:

                0   The system of Lake Togo: Lake Togo gathers the waters from the Zio and
                    Haho Rivers before flowing into the ocean through the lagoon mouth of
                    Aneho. This mouth has a strange evolution; having been long closed by
                    a spit of barely 30 meters, it discharges water collected from brooks
                    into the Mono River through the latter's effluent, the Gbaga. When the
                    water rises, the whole area is flooded and since 1987, with the
                    construction of jetties at Aneho, an opening has been made at Aneho
                    which serves as a permanent mouth for this system of Lake Togo.

                @   The estuary of Mono is a hydrological complex characterized by the
                    courses of the Mono and Koufo Rivers and the tidal flows. The dynamic
                    behavior of this sector is linked with the variations of the tides and
                    of the flow of the river. During flood time, the flow is enough to push
                    back the saltwater zone beyond the shoreline.       Inversely, when the
                    freshwater flow is at a low level, the saltwater contact goes up to
                    Agome-Seva (40 km). This part of the valley (6 m IGN) and Lake Athieme
                    are completely under the influence of the tide.

                                                   23











              West Africa

                       The Delta of Oueme is the most important hydrological element of this
                       area. It is characterized by the regime of the Oueme-So system, which

                       is influenced by the tropical rainfall pattern of the upper basin of
                       River Oueme and the tidal currents.

                   All these inlets have undergone serious changes since the nouakchottian
              transgression that put the different barriers in place.       First of all, the
              construction of successive spits has diverted all the inlets toward the east.
              Such is the case of the valley of Zio and of Lake Togo, which used to run into
              the sea at the level of Kpeme but today uses the artificial channel, which is the
              permanent mouth of Aneho. The Mono River used to pour its waters into the ocean
              at Grand Popo; it currently discharges through the opening at Avlo, which became
              a permanent mouth only a couple of decades ago. The Oueme River that flowed into
              the sea at Lagos before the opening of Cotonou channel in 1986, can only be
              explained by this progressive migration toward the east for 5,000 years. These
              inlets are often blocked by the construction of different spits, which often
              provoke catastrophic floods during the rainy season.      Such was the case of
              Cotonou in 1985, which prompted the opening of the channel in 1986; even after
              this opening, floods were reported in 1907, 1929, 1935, 1942, 1968, and 1987.

                  Those spectacular floods made it possible to map out marshy regions which
              are more than 65% of the area in the Gulf of Benin. They are more widespread in
              the estuaries of the Mono and Oueme where there are only few subaerial islands
              whose banks are covered with mangroves.      In all of the coastal plain, the
              depressions between the islands are swamps whose landscapes look like littoral
              meadows.




























                                                     24











           COASTAL EROSION AND MANAGEMENT ALONG THE COAST OF
                                            LIBERIA


                                     DR. EUGENE H. SHANNON
                                      Geologist/Director
                                  Liberian Geological Survey
                             Ministry of Lands, Mines & Energy
                                       Monrovia, Liberia






         INTRODUCTION

               Beach erosion affects all coastal countries of the world, including
         Liberia.

               The environmental consequences have often been devastating. In some cases,
         whole communities have been displaced -- or worse, wiped out. In addition to
         extensive personal properties, major losses have included port facilities,
         bui I di ng i nfrastructures, recreati onal f aci 1 i ti es, and agri cul tural , i ndustri al ,
         and residential land.

               As more and more infrastructures are developed along shorelines, erosion
         seems to accelerate because of the nature of the type of development.          For
         instance, port facilities tend to promote erosion. It is, therefore, essential
         to keep in mind the interaction of developmental activities with natural factors
         so that such development is not threatened at a later date. For example, the
         construction of the Free Port of Monrovia, the Hotel Africa, and the Villas has
         accelerated erosion, causing loss of beaches and buildings down the coast.

               Sea level rise from the greenhouse effect would aggravate all of these
         problems. Unfortunately the Ministry responsible for assessing erosion has not
         conducted any studies of the implications, of sea level rise, and we were unable
         to undertake even a preliminary inventory of the likely consequence -- let alone
         the appropriate response strategies. Nevertheless, the Ministry of Lands, Mines,
         and Energy recognizes the increasing importance of global warming and the need
         to participate in the international process. Given these limitations, this paper
         discusses Liberia's current thinking on existing erosion problems, with a hope
         that it will help researchers trying to understand how our country would respond
         to accelerated sea level rise.





                                                25











              West Africa

              The Importance of Erosion

                   Coastal erosion is a dynamic process resulting from an imbalance between
              sand accretion and erosion by the sea or wind.         When equilibrium is not
              established between accretion and removal of sand, erosion becomes inevitable.

                   Both manmade and natural factors induce shifts in the equilibrium of
              alongshore transport. General topographic, geologic, and meteorological features
              constitute natural process components, while the construction of hydraulic
              structures, such as port facilities, dams, buildings, and beach mining, tends to
              induce the artificial component.

                   Control of coastal erosion is , very important in the context of the
              development and management of coastal environments. However, choosing the type
              of technology appropriate for solving this problem requires an understanding of
              three essential elements:

                   0  the basic physical processes of coastal erosion, such as wave behavior,
                      currents, and tides;

                   0  human-induced (anthropogenic) changes in the physical coastal process,
                      which also contribute to erosion; and

                   0  the structural and nonstructural solutions to the problem.

              While physical factors and the range of appropriate technologies may exist,
              sometimes for a developing country the decision of which technology to use with
              regard to cost becomes very complicated because of the relative scarcity of
              resources needed for the solution -- e.g., equipment, skilled manpower, financial
              support.

                   The development along,the coastal zone has been dramatic in the last few
              decades. Construction has included resort settlements, residences, commercial
              harbors, and a few coastal defense structures.    Most of these structures were
              built in response to a particular situation and with little concern for
              environmental or downcoast impacts.


              COASTAL PROCESSES

                   The coastal perimeter consists of both landward and seaward portions of the
              shoreline.  Erosion of the shoreline starts when the removal of sediments is
              greater than accretion. Both of these processes -- erosion and deposition --
              constantly occur along the shoreline.    Therefore, an assessment of shoreline
              erosion must consider the difference in the rates of erosion and accretion within
              a fixed time span.

                   The sources of the sand we find on the shoreline originate from upland
              drainage systems -- e.g., rivers, coastal fastlands, and offshore outcropping of
              landward deposits. These systems are responsible in the long run for secondary

                                                     26











                                                                                     Shannon

          sources, such as beaches, sand dunes, and offshore deposits. Any disturbance of
          these source materials, for example by wind and water, which are the ultimate
          agents responsible for accretion and removal of coastal material, will lead to
          erosion.



          NATURAL CAUSES OF EROSION

               The natural processes of erosion are usually impossible to resist.        The
          natural shoreline is a result of the interaction between the processes of
          erosion, accretion, and meteorological and oceanographic conditions. Any changes
          in one of these conditions will result in the transgression or regression of the
          shoreline. Natural erosion is a geological process that seeks to establish an
          equilibrium among the natural forces. Examples of natural processes of erosion
          include the influences of tides, waves, eustatic changes in sea level, storms,
          hurricanes, tsunamis, coastal characteristics, and loss of sediment supply.


          ANTHROPOGENIC CAUSES OF EROSION

               A significant amount of erosion is due to improperly planned human
          interferences with natural coastal processes, such as dam and port construction,
          beach sand mining, drainage alteration, devegetation and farming, construction
          near the shore and beach, disposal of solid waste and landfill sludge, inlet
          stabilization, and dredging.

               The coast of Liberia is approximately 600 kilometers (350 miles) long. It
          includes deltaic plains, fan deltas, coastal plains, and steep slopes produced
          by faulting and intense erosion.     Part of the coastline is characterized by
          drowned valleys with bays, promontories, and pocket beaches. Portions of the
          coastline are composed of sand pits, barrier beaches, and lagoonal environments.

               Sands of the Liberian coast drift from Harper City in the southeast to
          Robertsport City in the northwest.    It has been estimated that 7.2  X 106  cubic
          meters are transported from rivers annually, and that some  20% of this volume is
          redeposited on the coast. A decrease in supply of sand is due to a decrease in
          the transport of river sediment and the rate of littoral    drift, which results
          from the construction of manmade structures on the coast.



          PREVIOUS WORK

               Studies and remedies related to coastal erosion are primarily the
          responsibilities of the Ministries of Lands, Mines, and Energy; Public Works; and
          Rural Development.

               Three organizations have conducted studies on the coastal erosion of
          Liberia: the Japanese Agency for International Development; the Ministry of
          Lands, Mines, and Energy; and the LAMCO J.V. Operation Company.


                                                 27











             West Africa

             Japanese Activities

                   In 1978, the Japanese Agency for International Development conducted studies
             for three weeks to identify the various causes of erosion along the Liberian
             coastline. Their studies took them to Robertsport, Greenville, Harper, Buchanan,
             and Monrovia. Two principal causes of erosion were identified by the Agency:
             (1) drifting of river outlets, and (2) ;changes in the balance of littoral
             transport caused by blockage of natural sand drifting, which was the result of
             human activities -- e.g., construction of breakwaters, beach mining, and possible
             reduction of sand supply from the rivers by the construction of the St. Paul
             River Dam.

             LAMCO J.V. Operating Company

                   The rate of erosion increased tremendously in Buchanan after erection of the
             breakwaters, especially within the port area.       Although sand was naturally
             deposited east of those structures, active beach mining has also been intensive,
             thereby accelerating the process of erosion.

                   In recognition of these threats to the beaches with regard to coastal
             erosion, the Ministry of Lands, Mines, and Energy recommended that LAMCO
             undertake countermeasures, especially north of Buchanan, either by constructing
             groins or by providing artificial sand nourishment.        Dr. Eugene H. Shannon
             (Director, Liberian Geological Survey) et al. (1979) reported that two groins
             each reportedly valued at $35,000 (U.S. dollars) were constructed and proved to
             be rather effective at the time.      Boulder dumping was also instrumental in
             reinforcing the shoreline against erosion. After this exercise, the Ministry of
             Lands, Mines, and Energy devised a scheme -- Environmental Monitoring -- to
             monitor the extent of beach erosion from time to time in Buchanan.

                   Whereas the degree of protection was adequate in certain areas, other side
             effects developed, especially along Atlantic Street in Buchanan.             While
             government, through the Ministry of Lands, Mines and Energy, has continuously
             recommended that LAMCO establish more groin systems, progress has been slow.

             The Liberian Government

                   Realizing the degradation of the country's shorelines by wave action,
             especially along areas with exorbitant infrastructures, the Government of Liberia
             set up a special technical committee in 1981, headed by the Ministry of Lands,
             Mines, and Energy, to investigate and find means of safeguarding Hotel Africa,
             the adjacent villas, and the beach. Other Ministries included Public Works and
             Rural Development.    After some studies, the committee estimated the rate of
             erosion as approximately 10 feet (3 meters) per year.

                   Dr. Ntungwa Maasha, formerly Head of the Geology Department of the
             University of Liberia, conducted a study between 1980 and 1982 along the Monrovia
             coastline between Wamba Town and Yatono. Results of his study indicate that 80%
             of the coastline of Monrovia consists of sandy beaches that erode at a rate of
             0.5 to 4 meters per year. The only depositional area identified was West Point

                                                     28











                                                                                     Shannon

          beach, south of the Free Port of Monrovia. Natural shorelines were identified
          in the vicinity of lagoons. Dr. Maasha also reported that the littoral drift is
          everywhere from southeast to northwest, and that the long-shore current velocity
          varies between 16 and 31 cm/sec.

               A three-man Swedish team consisting of Hans Hanson, Lennart Jonsson, and Bo
          Broms conducted a one-week study in 1983 along selected areas of the Liberian
          coastline. Besides substantiating that harbor construction and other forms of
          human interferences have aggravated the erosion problem, they gave an annual
          figure of about 50,000-60,000 cubic meters of sand respectively, for deposition
          and erosion south of the Free Port of Monrovia. They reported the sediment yield
          of the St. Paul River as 1.5 x  106 cubic meters/year.   They also reported that
          the most frequent waves arrive from south to southwest, and that their heights
          change seasonally from 1.3 m (highest) in June to 0.6 (lowest) in March.       For
          littoral transport, a wave height of about 1.1 m is said to be representative.
          A semidiurnal tide is also reported, with a tidal range of about 1-1.5 m. The
          tide induces long-shore currents with ebb stream directed to the south and north,
          respectively, flood currents being much weaker (5-15 cm/sec, as opposed to 15-45
          m/sec for ebb currents).


          BEACH EROSION STUDIES IN LIBERIA

               Like most coastal nations, Liberia is faced with serious problems as a
          result of changes in the configuration of its shoreline due to the activity of
          the ocean waves. Erosion is causing shoreline recession in some cities -- for
          example, in Buchanan, Greenville, Harper, and Robertsport.        Most recently,
          alarming incidents of beach erosion along some portions of the Monrovia coastline
          have resulted in loss of land and shorefront properties.

               Because of the economic and environmental problems associated with beach
          erosion, the Government of Liberia -- through the Liberian Geological Survey,
          Department of Mineral Exploration and Environmental Research, Ministry of Lands,
          Mines and Energy, the University of Liberia, other government agencies, and
          foreign institutions, as mentioned in the previous section -- has endeavored to
          implement beach erosion studies and recommend possible remedial measures related
          to the development of shorefront properties. However, all of these studies have
          been focused on Monrovia as a result of finance.

          OAU Village

               The beach of the OAU Village area is characterized by more or less
          horizontal layers of black and brown-white, unconsolidated, medium- to fine-
          grained sands.    In some areas, especially around Fanti Town, diabase and
          melanocratic gneisses outcrop in the sea and serve as wave barriers. As a result
          of the change in the balance of littoral transport caused by blockage of natural
          sand drift resulting from human interferences, the beach of the OAU Village is
          estimated to be receding at the rate of 3 meters a year.



                                                 29










             West Africa

             New Kru Town Area

                   The New Kru Town area is characterized by very fine- to medium-grained sand.
             The area is separated from the OAU Village by the St. Paul River. At the mouth
             of the St. Paul River, the beach is flat and broad, and it is composed of poorly
             stratified white clayey sand, which is dusty and crumbly when dry.

                   The recession rate around the New Kru Town area is more or less the same as
             around the OAU Village area. The area is affected by the same phenomena. Away
             from St. Paul River, toward Point Four, the beach face becomes narrower,
             gradually developing into a high escarpment about 5-7 meters higher.

             West Point - Hamba Point Area

                   The West Point spit/bar, which lies at the mouth of the Mesurado River, has
             characteristics similar to those of the area around the St. Paul area, except
             that in West Point the flat and broad floodplain of the Mesurado River has been
             destroyed by manmade structures, mainly zinc shacks.       The Mamba Point area,
             however, is characterized by massive diabase outcrops with steep cliffs, which
             reflect wave energy, induce offshore sediment transport, and prevent the
             formation of any beach.    The diabase is well jointed horizontally as well as
             vertically. Boulders of diabase that have been undermined by Wave action can be
             seen in the littoral zone. West Point-Mamba Point is the only area that has been
             identified as a depositional area, especially south of the Free Port of Monrovia.

                   The strip of shoreline from Cape Mesurado to the OAU Village area is within
             an embayment. Wave activity is much more complex because of wave refraction at
             the cape and at the Free Port breakwaters.      This human interference has thus
             created an imbalance in the geomorphic system, and the adjustments in morphology
             need to be critically investigated.

             Hamba Point - Elwa Area

                   The beach area between Elwa and Mamba Point is mainly characterized by
             coarse-to-medium to fine-grained sand in alternating black and white layers.
             With the exception of the area behind the Executive Mansion and near King Gray,
             where large diabase outcrops are discernible, the rest of the beach area is
             uniform, with sporadic diabase outcrops in the area.

                   There is an unusual increase in black sand (heavy minerals) in the Congo
             Town area, with band thickness ranging from I to 2 feet in some places. This
             area of increased heavy mineral occurrences is low-lying, swampy, and separated
             from the mainland by small lagoons.

                   Neutral shorelines were identified in the vicinity of lagoons where sand
             accretion and san removal are more or less in equilibrium.





                                                     30











                                                                                          Shannon

           METHODOLOGY

                The methodology employed by the Liberian Geological Survey in the erosion
           studies of Liberia includes beach profiling, sediment sampling, and the
           observation and measurement of the littoral parameters in the field, as well as
           granulometric analyses in the laboratory. Aerial photographs and maps were also
           used to establish stations for studying and future monitoring (Figure 1).

           Field Methods

                A ground survey of the entire 35-km Monrovia coastline between the OAU
           Village area and ELWA was conducted between May and July 1984.            During the
           survey, activities were mainly geared toward a better understanding of prevailing
           sedimentary processes and also the dynamics of the Monrovia littoral environment.
           The following paragraphs provide a complete breakdown of field activities.

           Beach Profiling

                Permanent features, such as trees, house fences, and electric poles, were
           used as reference (bench) marks for profile measurements. In the absence of such
           features, temporary markers were installed for easy location.          Profiles were
           measured along lines perpendicular to the shoreline and extending to the existing
           water line. Conspicuous morphological features along the active beach face were
           used as survey points. Measurements were made using a surveyor's level and a
           stadia rod, and each station included a series of substations adequately spaced
           along the beach.

           Slope Measurement

                The foreshore slope angle was measured directly using the clinometer of the
           Brunton compass leveled on undisturbed portions of beach slope. Angle values
           given represent an average of readings collected from various places at a given
           site.

           Wave Measurement

                The wave periods at various locations were estimated by timing the breaking
           interval of incoming waves.       At each location, the estimate was done in
           triplicate and the mean was used   as the representative value. These mean values
           were then combined in statistical fashion, and the resulting average was used as
           the representative value for Monrovia and its environs. The average wave period
           was subsequently used to empirically calculate other wave parameters, such as
           length, height, and celerity.

           Wind Direction

                The direction of wind movement was measured using a flag and a Brunton
           compass. The flag was placed on the beach, and the compass was aligned with it
           to give the direction of wind approach.          The various directions obtained
           throughout the study area were combined statistically to give an average value.

                                                    31











                       West Africa





                                         7
                                           A
                                           Ir
                                            7

                                                                         S  PAUL !JIVERI
                                                          AU                                                                  MN    4
                                                     S ii  IN


                                                   0                                                                                0a
                                                                                                                                    z
                                                              NEW                                                                   0
                                                               KRU  TOWN
                                                            S2                                                                  -   a
                                                                   RUSHROO ISLAND                                                 4
                                                                                                                                  2


                                                        FREE                                                                        JOHNSON VILLE
                                                        PORT



                                                   S


                                           WEST   IOINT


                                                   4

                                         CAPE
                                       MESURAOP
                                                MONROVIA



                                                  S                MESURADO RIVER.
                                                    5                /'--,,   - I

                                                                                S PRf No
                                                               0                 PAYNE
                                                                         S      AIR FIELD

                                                                        4'
                                                                             BERM 0
                                                                             BEACH


                                                                                            97                   SHERMAN
                                                                                                                    LAKE

                                         EXPLANATION             0       1    2      3     4      5
                                                                                                   xM
                                       Station Location          Fig. I  STATION LOCATION    MAP                        S    KING GRAY
                                                                 (MONROVIA BEACH STUDY       LOS)                        9



                                                                                                                         ELW
                                                                                                                              S
                                                                                                                               10





                      Figure 1. Station location map (Monrovia Beach study).

                                                                                    32











                                                                                          Shannon

            Sediment Sampling

                 The width of the beach varies from 9 m to 27 m.    Therefore, a single sample
            taken at a station would not serve as a representative sample of a given station.
            For this reason, a triangular pattern was used in sampling each station or
            substation, with samples taken at the three apexes, as shown in Figure 2.

                 All samples marked A are those taken on the berm   or overwash terrace, while
            those marked B and C were taken at the sea edge and at the midpoint between A and
            B, respectively.

                 Each sample was approximately labeled commensurate with the station or
            substation number. A geologic description of each sample was noted in the field
            book.

            Wave Mechanics of Monrovia and Its Environs

                 Waves approach obliquely to the shoreline in Monrovia and its environs. The
            obliqueness increases in the area immediately north of Cape Mesurado, where
            shoreline orientation approaches parallelism with the apparent direction of wave
            approach.

                 Of a total of 40 readings of the direction of wind approach, 28 are toward
            the southwest, 4 toward the northwest, and 8 toward the southeast (Table 1 and
            Figure 3). Values to the southwest are more frequent; they have a range of 77
            degrees, a mean of 38.3 degrees, and a standard deviation of 25 degrees. This
            indicates that at the beginning of the rainy season (May-June), the Monrovia
            coastline receives winds coming predominantly from the southwest (Figure 3).
            Considering wind-generated waves (sea waves), the estimated average direction of
            wave approach is South 38 degrees West. This bearing compares closely with wind
            records at the Spriggs Payne Airfield Meteorological Station.

                 The mean wave period for the Monrovia coastline is about 12.96 seconds. The
            statistical analysis is shown in Table 2. Using empirical equations (Friedman
            and Sanders, 1978), the deep-water wavelength (Lo) and the deep-water celerity
            (Co) were calculated as follows:

                 L@      1.56T2
                         262.02 m
                         1.56T
                         20.22 m/sec               Where T = wave period.

            These values correspond to an initial breaker depth (H,) of 13.3 m (L./20), and
            the associated deep-water weave height (H.) is found to be 10.22 m (0.039 LO).
            Considering transformation due to shallow-water conditions, the wave-length (L,)
            and the celerity (C,) at initial breaking are found to be 139.1 m and 11.33
            m/sec, respectively.    Wave height at initial breaking (H,) is found to be 10.4
            m, and wave break mainly by plunging, with spilling types being observed in a few
            places. In the opinion of the authors, the landward limit of the breaker zone
            will be marked by a water depth equal to about one-half the deep-water wave

                                                     33











              West Africa












                                     A       BERM                   A           BERM                A









                               BEACH FACE                          BEACH FACE
                   C                               C                               C





               A                             SEA EDGE               B       SEA EDGE



              Figure 2(A). Sample pattern in plan view.


                    A












                                                    C











                B

              Figure 2(B). Sample pattern in profile.

                                                        34










                                                                                                              Shannon

             Table 1. Statistical Analysis of Wind Direction Along the Monrovia Coastline
                            (1984 data)

                                      M easur9d Direction      Of wind       Approac    t Flog ging
                                      Set I                        Set   2                   Set   3
                                S  XW Frequency          S X*2 E      Frequency       N XGW       Frequency
                                              (fl                       (f   2)            3       M)
                                   10            3          15               1          so             I
                                   13            1          2 2              1          63             1
                                   15            1          25               2          75             1
                                   17            1          30               1          85             1
                                   is            1          32               1
                                   %19           1          37               1                  *fene4
                                   20            3          45               1
                                   25            2
                                   27            1                  *f
                                   28            1                     2zn2 a 18        N         n2       3
                                   30            2
                                   50            1        Who re    N  ='Total 4#    t measured values,
                                   52            1
                                   55            1             N       28 t 6 t      4 = 40
                                   60            2
                                   64            1          n         2Y     X loo = TO% of It
                                   71            1                       40
                                   75            2
                                   85            1          "2  AL           )(100 = 20%
                                   87            1                    Y4 0
                                           flu n lr_ 28     n  3 a    4      x 100 a 1.0%
                                                                      /40


              Figure 3.      Diagrammatic illustration of             dominant wind approach for Monrovia,
              based on Table 1.


                                                  N






                                                                             0           50           100%
                                  W                \>              E



                                                                  35










                    West Africa

                    Table 2. Statistical Treatment of Wave Period Along the Monrovia Coastline


                        WAVE                               RELATIVE
                        PERIOD      FREQUENCY              FREQUENCY       DATA          GROUPING
                        W SEC          (f)  I MW               f/n       GROUPING        FREQUENCY-


                        6.6            1         6.6         .016            M
                        7              1         7           .016         (7.5
                        8              1         8           .016       6.5-8.5              3          -GROUPING INTERVALS     CONSIDERED
                        8.9            1         8.9         .016
                        3              4         3.6         .065            M
                        9.8            1         9.8         .016         (9.5)                                                   mid-pt.
                        10             3       30            .048        8.5-10.5            9          ares  1)    4.5  - 6.5       5.5
                        10.7           1       10.7          .016                                             2)    6.5  - 8.5       7.5
                        11             3       33            .048                                             3)    8.5  -10.5       9.5
                        11.5           1       11.5          .016          11.5                               4)  10.5   -12.5    11.5
                        12             5       60            .081      10.5-12.5            10                5)  12.5   -14.5    13.5
                        13             8     104             .129                                             6)  14.5   -16.6    15.5
                        13.1           1       13.1          .016                                             7)  16.5   -18.5    17.5
                        13.8           1       13.8          .016          13.5                               8)  18.5   -20.5    19.5
                        14            11     154             .177      12.5-14.5            21
                        15             8     120             .129
                        15.2           1       15.2          .016                                             Mode -    14.0 sec.
                        15.5           2       31            .032          15.5                               Median-   13.1 "
                        16             6       96            .097      14.5-16.5            17                Mean -    12.96 "
                        17             1       17            .016          17.5
                        17.7   1       1       17.7    1     .016      16.5-18.5             2
                        -             62                   770-



                        n = 62;x     12,96  s - 2.53    sec.




                    height    (H,,/2) .    At this arbitrary depth of final breaking (h = 5.11 m), the
                    characteristic wavelength (L,) and celerity (C,) are found to be 90.92 m and 7.08
                    m/sec, respectively. The wave height at final breaking (H,) is also found to be
                    12.57 m.



                    COASTAL SEDIMENTS OF THE MONROVIA BEACHES

                          The beaches of Monrovia are characterized by medium- to coarse-grained sand,
                    consisting of mostly quartz, with iron stains that give a brownish-white
                    appearance. Heavy minerals (black sand) occur in minor amounts throughout, with
                    an apparent increase in the Congo Town and ELWA areas, as evidenced by locally
                    high bulk densities.

                          Representative histograms of the beach sand are shown in Figure 4 with
                    respect to locality and the dominant size fractions, and a generalized variation
                    line is shown in Figure 5. Local deviations from this general line were observed
                    in the vicinity of rock shorelines where grain size is apparently larger.




                                                                            36










                                                                                                                                                                                 Shannon











                                                                                                                                                                                   G1 INEA

                                                                                                                                                                   LEW
                                                                                                                                                                                             IVORY
                                   YATONO                                                                                                                                              f     COAST

                                                                                                                                BEACH SAND
                                                                                                                                                                 N INRC,
                                     HOW                            0                                                           OUTCROPS
                                       BEAC'                                                                                                                           N.k@44,;>C               j
                                                                                                                                MOTOR ROAD

                                                                                        R11 ER                                  RIVER OR CREEK
                         i8o
                         40                      f
                         W                       A
                                                      HO                                                                                                         BEACH EROSION STUDY AREA
                         2                                                                                                      SAMPLE LOCATION FOR           01 NDEX MAP OF LIBERIA SHOVANG LOC.
                         18                      C,     FRI                                                                           HISTOGRAM              (*AUI- E L WA)
                         -2- 01                  0


                         T*    2                                    NEIA
                         WI%
                         6"                                         TOW@P-4
                         0                                          pol FOUR
                         So
                         4
                         I.                                           ISHROD                                                                         -1
                                                                     88  ISLAND                                                         0 UNITS - 2     0 1 2 3 4
                         -1.1 01234 5                                                                                                                2 1 I;i 1/4 @; or
                         WI%                             FRErPO T                                                                               PHI.MILLIMETER CONVERSION
                         70                                 of
                         60                             MONROVIA
                         50
                         40

                              01234 5            WESTPOINT                                                    Ak
                                                 WE

                                                 C@Apr
                                                 P
                                  4              MES RAI     INC
                                                 MAMBA                                 R
                         go                      POIN
                              0 123 4 5


                                                     EXECUTIVE               MONROVIA
                         W1%                            MANSION
                         70
                         '60
                         50[@
                         .0

                                                                                                                           VOWN
                         '0                                                       6 R                              ONGO
                         -2-1 9 1 2345                                                  13EACH          -                                                  0            2                   Sk.
                                                                                                4)-4,14,
                                                                                                    4,         SHAR N L K
                                                 W1%                W1%                         WI%     0                                                             scale
                                                 70                 TO                          0              0                           KING GRAY
                                                 .06                60    7
                                                                    5C                          5
                                                 40
                                                                    40
                                                 30                 30                          30                                               E I-Wr -.ft
                                                 20                 20                          20
                                                 10 2-1 0 1 2 34155 10 2 -t 0 1 2 345           10 2 -1 01 234 5
                                                                                                                                                                                      "MSA To NJ


                         Figure 4. Map showing sediment size variation along the coast of Monrovia (OAU-
                         ELWA).


                                                                                                           37












                                                                         M                     r-          = -n                                         4' Co. W            - 0
                                                                         r-                    -A.         C)                                           4- -1- -1.
                                                                         le                    c+          =
                                                                    lw > 0 x =                 c+          -1
                                                                    (A c@ C         U:)        0           0  -1
                                                                            -a          --1    -5          <  (D
                                                                    -h iw   1w      C+ =       iw
                                                                    010     C+      = VD                   1w L"
                                                                     .j CD  (D      M
                                             X                      --1     0-0                            0                     HOTEL AFRICA_                          0   1 0
                                                                    0    m %@ 0                            0                          OAU
                                                                    3E   (D r-      0,                     tv
                                             (D      4m     co      1A              -.j C+                 t, p
                                               I                                'w  o                      C+ -s
                                             (D      -4                                        V+
                                                     co                                 0
                                                                         1w a   CL -, -1
                                             A)                                     1w lw
                                                     C-1.                CL ,           -j
                                                     0                   0  Jw  C+ V+                      (D                      POINT FOUR
                                     @4                                         =1 m               i                                                                    o     0
                                                                         (A -1      m CL                                             KRU TOWPr
                                             su      _j
                                                                         = m    (D
                                                     (D
                              01                     W
                                     x                         PQ                   m   -h
                                                     --,    ,               m A     m   c+
                              x              (D                                 ;@'y
                                     co      C)      0      0                   (D      'W                                           N PA
                              40       w                    w                   =   X   -                     (a                                 -                            0     o
                                                                         m C.+ 1+ lw    0                                     SOUTH BREAKER
                                                            lw              ju '. 4r+
                                                                            lr+ Ap m to
                                                                         > @. @ -1
                                                                         0 <            C+
                                             m                           0 m        3E  =
                                                               4@b              __j 1w  (D                    0
                                             0              (A           0  @. a <
                                             -h                          I  = = (D                                              WEST POINT                              0
                                                                         9L                                   0
                                                                                                              -h
                      00                                    su              (D  0,00
                                                                         r+ =1  -1 =- <
                                             0-                          00     (D C.+
                                             (D                             (D          lw
                                                                                                              Z.              MAMBA POINT                               0
                                             0                           jw su                                ju                      BTC
                                                                         cr =   (D      0
                                                                         1w to  0.%@
                                                                         3
                                                                            --j @..     su
                                                                         E
                                                                         jw
                                                                         (D 0
                                                                         c+ -hr+ M                            lu        PAN AFRICAN PLAZA                               CA
                                                                                                                            B
                                                                         W -4       -0                                        ERNARCPS BEACIT
                                                                            00 C+ 0
                                                                                -1  c+
                                                                            CL Jw       V)
                                                                            CD =
                                                                         1--tow     C+                        (D
                                                                         to-s-o     @.
                                                                         00 M 0     su 3E                     -h         CATHOLIC HOSPITAL                                    0
                                                                                        1w                                    CONGO TOWN
                                                                                        -1                    ju
                                                                                        CL
                                                                         c+ cr
                                                                         =r C+ 1w in                          0
                                                                         (D Jw C+ (A                                       SHERMAN LAKE
                                                                         n      (D =                          W                                                         0   1 0
                                                                         lw         0                                           KING GRAY                                   I


                                                                                        =r
                                                                         iw             X
                                                                                        (D                                           KING GRAY
                                                                                    to  V)                    C+                       ELWA                                 1 0
                                                                                    t<  C+
                                                                            M (D                              (D
                                                                                                                                                                    iv      in
                                                                                                                                                               0











                                                                                      Shannon

                Within the nearshore zone, littoral transport will be affected by waves of
           translation.   The height of these translatory waves was evaluated from the
           difference between wave height at various points of breaking and the original
           wave height (Hj.   Hence, the minimum height of the waves of translation along
           the coast,of Monrovia is-estimated as 0.2 m (H,-H,,), and the maximum height is
           estimated as 2.35 (H,-H,,).   However, a representative height (H,) of these
           translatory waves was estimated using the mean of H, and H, (H.), and the
           calculation is given below:

                Hm   (HI + Ht)/2

                     11.495 m2

                     11.495 - 10.22

                      1.275 m

                Therefore, for the littoral transport, a wave height of about 1.3 m is most
           probably representative of Monrovia.    Using this value for H. in the equation
           given previously, the longshore energy flux is found to be 9.68 joules/sec, and
           the longshore sediment transport rate is found to be 7.26 x   104 m3/yr.

                The angle of wave incidence for that portion of the study area immediately
           north of Cape Mesurado is about 15 degrees. The longshore energy flux along this
           strip is estimated as 17.47 joules/sec, and the longshore sediment transport rate
           is estimated as 1.31 x 10' m3/yr.-

                The littoral drift is therefore greater within the vicinity of the Free Port
           breakwaters. This indicates that waves within this area have a greater capacity
           to transport coastal materials -along the shore.


           COASTAL BEACH EROSION CONTROL

                Various methods are available to fight the coastal erosion problem, but
           basically they fall under either structural control or nonstructural control.

           Nonstructural Control Methods

                Most nonstructural methods only lessen or regulate the problems caused by
           erosion, rather than prevent, halt, or retard erosion. They are grouped into
           passive and active methods.

           Passive Methods

                The passive methods include:

                0 Land-Use Controls: This means that permission should be granted only
                   for structures that have to occupy waterfront sites. All the structures
                   associated with permitted waterfront should be movable or, at worst,

                                                  39










             West Africa

                      semipermanent and capable of quick, inexpensive repair.      They should
                      always be designed to minimize damage.

                      Coastal Setback Lines: This requires that all constructions on coastal
                      front should be placed at a safe distance from the shoreline.

             Active Methods

                  0   Move Threatened Structures: Threatened structures must be moved a safe
                      distance from the shoreline. This may be less expensive than trying to
                      control the erosion that threatens them.

                  0   Vegetative Methods: These methods serve to slow the rate of erosion,
                      rather than stop it.    They include stabilization of sand dunes, and
                      bluff and bank slopes with plantings, as well as the creation of     salt
                      marshes to absorb wave energy.        These methods are employed     with
                      structural methods. For example, where a seawall or revetment is     used
                      to stabilize the base of a cliff, bluff, or bank, plantings may be   made
                      to control erosion from surface runoff and wave overtopping.

                  Whenever possible and economically practical, every effort should be     made
             to correct or modify manmade increases in coastal erosion before building     what
             may turn out to be much more costly erosion control structures.

             Structural Methods of Erosion Control

                  Shoreline-hardening structures make the land mass more resistant to
             erosional forces and protect facilities landward from the effect of wave action.
             They tend to protect only landward infrastructures and have no beneficial effects
             on adjacent shorelines or on beaches seaward of them.          Shoreline-hardening
             structures include seawalls, revetments, and bulkheads (see Appendix 2 for
             diagrams and pictures of these structures). The characteristic design of these
             structures will depend on the height, length, shape, and degree of differences
             in texture permeability of porosity.


             RECOMMENDATIONS

                  Because of the extent of beach erosion and its imminent threat to
             investment, especially along the coastal front, the Ministry of Public Works has
             proposed a temporary solution for reducing the rate of erosion at the site. The
             technicians at the Ministry have estimated 125 working days at a total cost of
             $2.4 million (U.S. dollars). The project includes boulder dumping (with a clay
             dam on the villas side facing the sea) over an area 1,800 feet long and 50 feet
             wide. Engineering consultants estimated that 100,000 cubic yards of boulders and
             40,000 cubic yards of clay would be required (see Appendix 1).

                  The Ministry of Rural Development also recommended the following tentative
             structural measures that are capable of minimizing the erosion problems at Hotel
             Africa: Appendix 2, a stone revetment ($0.98 million, U.S. dollars); Appendix

                                                     40











                                                                                       Shannon

          2, a curved-face wall ($2.7 million, U.S. dollars); Appendix 2, bulkheads ($1.8
          million,  U.S. dollars); and Appendix 2, a concrete revetment.

                But these structures are just a first step for a small part of the Liberian
          coast.    At this time it is difficult for us to contemplate the nationwide
          response  to a rise in sea level from the greenhouse effect. Nevertheless, we
          conclude  with the recommendations that would help us address both the current
          problems  and the additional problems resulting from global warming.

                1.  During the dredging of the port by the National Port Authority, all sand
                    removed from the port should be deposited on the beach near the Hotel
                    Africa for nourishment of the shoreline.

                2.  The National Port Authority should be included on the technical
                    committee for future study of beach erosion.

                3.  Funds should be appropriated to the Technical Committee for logistics
                    that should be used to monitor the rate of erosion. This would provide
                    data for potential consultants. Also, a soil conservation and pollution
                    control division should be developed and empowered to undertake long-
                    range measures for adequate monitoring.

                4.  A Beach Erosion Control Commission should be created.

                5.  Specific beaches should be designated for sand mining.


          BIBLIOGRAPHY

          Fayia, A.K., J.B. Massah, F.T. Morlu and B.O. Weeks, B.O. 1987. A Survey of the
          Monrovia Beaches. Monrovia: Liberian Geological Survey.

          Friedman, G.M., and J.E. Sanders. 1978. Principles of Sedimentology. New York:
          John Wiley and Sons, Inc..

          Hanson, H., L. Johnson and B. Broms. 1984. Beach Erosion in Liberia: Causes and
          Remedial Measures. Lund, Sweden: University of Lund.

          Japan International Cooperation Agency. 1978. Report on the Beach Erosion in
          the Republic of Liberia. Tokyo: Japan International Cooperation Agency.

          Maasha, N. 1982.      Erosion of the Monrovia Beaches. Monrovia: University of
          Liberia, Department of Research.

          GDL. 1981. Government of Liberia. Report on "Seminar of Beach Erosion at Hotel
          Africa" OAU Village, Virginia, Liberia: Government of Liberia, Lands, Mines &
          Energy, Public Works & Rural Development, Technical Committee.

          Shulze, W. 1971. Notes on settlement research in Liberia. In: Rural Africana,
          No. 15, Liberia: An Evaluation of Rural Research. East Lansing, MI: Michigan

                                                   41










              West Africa

              State University.

              U.N.D.P. 1972. United Nations Development Program. Heavy Mineral Occurrence
              Between Monrovia and Marshall.    Technical: report No. 5.    Monrovia:    Liberian
              Geological Survey.

              White, R.W. 1972. Stratigraph and Structure of Basins on the Coast of Liberia.
              Liberian Geological Survey Special Paper No. 1.          Monrovia:,   Ministry of
              Information Press.
















































                                                      42











                                                                                         Shannon


                                               APPENDIX I

                                       ESTIMATE FROM PUBLIC WORKS
                                  OAU VILLAGE COASTAL EROSION PROJECT
                                          (Temporary Solution)


          Subject:     To prevent the coastal erosion at the OAU Village by the sea.

                In order to start the work on temporary solution, an access road is needed.

          1.    Mobilization for access road.

                A.  Access road 12' wide 6" thickness laterite surface length             1,8001
                    laterite = 1,000 C.Y.

                    Eguipment:

                    1.4 dump trucks
                    2.1 grader
                    3.1 front end loader

                    Fuel consumption:

                    4 x 25 gallon per day/trucks            100 gallons
                    40 gallons per day/grader                40 gallons
                    35 gallons per day/front end
                      loader                                 35 gallons
                                                            175 gallons/day

                    For 7 working days, all equipment         1,250 gallons. 1250 gallons of
                    fuel for the access road, and 100    gallons of gasoline.
                    Total cosf for fuel consumption @$1.88 x 1,250       = $2,350.00
                    Total cost for gasoline consumption @$2.09 x 100 = $ 209.00
                                                                            $2,559.00

          Temporary Solution:

                Although this solution is costly, it will delay the rate of erosion at the
          site. Also, the sand hauling from the beach around the area should be stopped
          by the authorities.

                The attached drawing gives a physical picture of what is needed at the site
          in question and the following are the descriptions:

          1.    Rolder Rock -- with clay dam on the Village side and facing the sea will be
                the Rolder with the length of about 1,800' and 501 wide at the top about
                100,000 cubic yards (cu. yd.) of Rolder will be needed and about 40,000 cu.
                yd. Clay will be needed.

                                                    43










               West  Africa

                     Personnel:

                     I Engineer                  @ $40.00/day          $ 40.00
                     1 Superintendent            @ $30.00/day          $ 30.00
                     20 Truck Drivers            @ $10.00/day          $200.00
                     20 Laborers                 @ $ 7.70/day          $154.00
                     10 Operators                @ $12.50/day          $125.00

                                                      Sub-total        $650.00/day

                     Eguigment:                       Fuel Consumption/Day

                     20 - 12 cu. yd.
                      dump trucks                               550/day
                     2  Trexcavators                            100/day
                     I  Dozer D/C                               50/day
                     1  Front end loader                        35/day
                     I  Mobile crane                            50/day
                     2  Pick-ups                                20/day  (gas)
                     1  Man-haul truck                          15/day
                     1  Compressor*                             830/day
                     2  Tankers*

                 Plus 20% contingency   fuel for  emergency equipment of the total consumption.

                     Minimum haulage/day:

                     4 Trips/day = 12 x 4 = 48 cu. yd.
                     40 cu. yd. Truck/day
                     Total volume of rock needed = 120,000 cu. yd.
                      for 20 Trucks = 48 x 20      960
                        No. = 120,000                 11000            125 days
                                  960                   8

                     Expenditures:

                     $650.00 x 125 days                                   $   78,000.00
                     $15/cu. A. x 12,000
                      (cost of B. Rock)                                   $     11800.00
                     Cost of fuel 100 x 125 x $1.88                       $   235,000-00
                     Plus 25% of fuel cost for:
                      Lubricant and fast moving parts                     $   60,000.00
                     Gasoline 2.09 x 250                                  $     5,225.00

                                                      Grand  Total        $2,178,225.00
                     Plus 10% contingency                                 $ 217,822.50
                                                      Total               $2,396,047.50

                     It should be noted that this solution   will only delay the rate of erosion,
               until a permanent solution is to be found.

                                                        44











                                                                                Shannon

        Permanent Solution:

             There should be a comprehensive study by the Engineering Division to find
        the causes of the erosion and the factors influencing it. The following facts
        have to be known:

             a)  Direction of wind
             b)  Frequency of waves
             c)  Direction of waves
             d)  Height of tide
             e)  Topography of the area
             f)  Soil test



                                                        Submitted by: Emmanuel Oseni
                                                                        Engineer/CB/MPW






























                                              45










              Plest Africa


                                                  APPENDIX 2

                                                STONE REVETMENT



                    ITEM                 QUANTITY      UNIT RATE               EXTENSION

              Ballast                    16764.50        25.00          $ 419,112.50
                (above 400 lba)
              Ballast                    12573.33        25.50             282,900.00
                                                       Subtotal         $  702,012.50
              Contingency                 12%                           $    84,241.50
              Transportation              20%                              140,402.50
              Placement                   7.5%                             -52,650.94

                                                       Grand Total:     $  979,307.44


                                               CURVED FACE WALL



                    ITEM         QUANTITY              UNIT RATE                EXTENSION

              Excavation         1955. cu.yd.            25.50          $    30,315.68
              Concrete Work      6286.67 cu.yd.          250.00          1,571,667.50
              Form Work          12% of concrete
                                          work             5               188,600.10
              Pile Work          15% of concrete
                                          work             5               392,916.88
              Back Filing        8941.04 cu.yd.          12.00             107,292.50
              Front Filing       1257.33 cu.yd.          20.00               25,146.70

                                                       Sub-Total:       $2,315,939.40

                                           Plus 15% contingency:          347,390.90

                                                    Grand Total:        $2,663,330.30



                                              BULKHEAD ESTIMATES



                    ITEM            QUANTITY           UNIT RATE                EXTENSION

              Ballast            50,293.33 cu.yd.        25.00          $1,257,333.30
              Contingency              12%                                 150,879.99
              Transportation           20%                                 251,466.66
              Placement               8.5%                                 106,873.33

                                                       Grand Total:     $1,766,553.30

                                                       46










                                                                                                 Shannon

                                                 Stone Revetment


                                   040



                                                              RIPRAP (1000lbs to 6000lbs Averaging 4000[ba)
           CRUSHED STONE                                               Chinked Witil One Man Stone
          UNGEREENED       A ND
                             IJNDER

                                                                                         NATURAL BEACH LINE




                                                   One Man Stone
                                                   20 lbs to 150lbs




                                               Concrete Revetment


                These are lighter construction which primarily functions as shore or beach
          protection against erosion from wave, tide, or current actions.



                                                       'SLAB




                                                          4-
                                                    SECTION THROUGH SLAB
                                                         uNDER JOINT



                   12"4

           EA OT14



                   WILL                 FLAP VALVE
                                                          Tb!)

                   4 FILL                            M H


                   ORIGINAL BEAGM
                      LINE












                                                         47











                  West Africa

                                                         Curved Face Wall (Seawall)

                         This structure is used for moderately severe wave action where the water
                  level is over the structural base, permitting the full waves to hit the wall.
                  This structure could also be used where poor foundations exist.





                                                                             WATER
                                                                       STILL
                  FILL





                     N     4









                                    -m -T-


                                              SHEET PILLER



                                 IF


                                                           Bulkheads lBreakwatersl


                        The primary function of bulkheads is to retain fill and secondarily to
                  resist wave action.

                                                              R&PRW ( 10001b - GOOOrjG)AW&Q9irq
                                                                      400068 chwAsd HN  a"
                                                                       man Ste"








                                                                                                                     V





         Oft MED STONE
         UNSCREENED 2V2a
         AND UNDER






                                              25- so


                  (photographs reproduced by permission of the                       Koppers Co., Inc., Pittsburgh,                   PA
                  (U.S.))

                                                                           48











          IMPACT OF SEA LEVEL RISE ON THE NIGERIAN COASTAL ZONE


                                     L.F. AWOSIKA and A.C. IBE
                 Nigerian Institute for Oceanography and Marine Research
                                             Lagos, Nigeria

                                                    and

                                              M.A. UDO-AKA
                          Federal Ministry of Science and Technology
                                   Kofo Abayomi, Lagos, Nigeria





          ABSTRACT

               Widespread erosion, flooding, and subsidence are already devastating vast
          areas of the Nigerian coastline causing severe ecological problems that have
          compelled the federal government to set up a special relief fund to mitigate the
          impact. A rise in sea level of approximately I m would aggravate the existing
          ecological problems through accelerated coastal erosion, more persistent
          flooding, loss of ecologically significant wetlands, increased salinization of
          rivers and groundwater aquifers, and greater influx of diverse pollutants. Other
          socioeconomic impacts include uprooting human settlements, disrupting oil and gas
          production, dislodging port and navigational structures, upsetting the rich
          fishery, forcing businesses and industries to relocate, wiping out the fledgling
          coast based-tourism, and generally increasing the level of misery. The several
          engineering counter-measures being presently proposed for coping with sea level
          rise are too expensive for a developing country like Nigeria with huge external
          debts. Responding to sea level rise should consist largely of keeping some steps
          ahead of the projected rise by slowly "disengaging" from the coast where possible
          and establ i shi ng and enforci ng set-back 1 i nes i n areas of new devel opment. Where
          this is not possible, as in heavily built up areas, emphasis should be on
          developing and implementing low-cost, low-technology, but nonetheless effective
          options.


          INTRODUCTION

                Along the coastal zone, probably the main consequence of an increase in
          gl obal temperatures i s an accel erated ri se i n gl obal sea 1 evel . Thi s wi 11 be due
          to the melting of alpine and polar glaciers and the thermal expansion of the
          ocean surface.


                                                     49










              West Africa

                   Estimates of the projected rise in sea level differ, sometimes markedly
              (e.g., from 0.45 to 3.65 m, according to various estimates), but the following
              assumptions were accepted at the UNEP/ICSU/WMO International Conference in
              Villach, 9-15 October 1985:    increased temperature of 1.5-4.5*C and sea level
              rise of 20-140 cm before the end of the 21st century, with the understanding that
              these estimates may be revised on the basis of new scientific evidence.

                   This paper examines the potential impact of climate change on the coastal
              and marine environment in Nigeria a 'nd suggests certain suitable policy options
              and response measures that may mitigate the negative consequences of the impact.


              GEOMORPHOLOGICAL SETTING

                   The Nigerian coastal zone extends for a distance of about 800 km between the
              western and eastern borders of the country with the Republics of Benin and
              Cameroun, respectively. It lies generally between 4010' and 60201N latitudes and
              2045' and 8035'E longitudes adjacent to the Gulf of Guinea.

                   The coastal zone is mounted on a voluminous, though localized, sedimentary
              protrusion into the Gulf of Guinea ocean basin comprising a 12-km-thick pile of
              Cretaceous and Tertiary sediments, close to the juncture of two of the boundary
              realms of the Guinea basin (Allen, 1964).      The origin and evolution of the
              Nigerian coastal zone are closely linked with the Mesozoic (Upper Jurasic to
              Lower Cretaceous) opening of the Atlantic Ocean and by different, more recent
              phases associated with the structural deformation of the East African Rift
              Systems.

                   The coast is bounded laterally to the north by an extensive river floodplain
              (area, 8400 square kilometers), which slopes southward from about 20 m above sea
              level in the Onitsha gap (Figure 1). This narrow zone is mounted on the Benue
              Valley and contains the main channel of the Niger River before and after
              bifurcation.   This plain broadens southward with a decrease in slope and
              subsequent increase in the density of tributaries of the major drainage channels
              and down to the coast.

                   To the south is the Continental Shelf characterized by more or less uniform
              gentle slopes broken at specific points by the recognizable submarine canyons
              (Avon, Mahin, and Calabar Canyons).

                   The Nigerian coastal zone is composed of four distinct units with different
              surficial configurations (Figure 2). A 200-km-long barrier lagoon coast in the
              western part is followed by 75 km of transgressive mud coast, which tapers into
              the dominating 450-km-long and beach-ridge-barrier-island-rimmed Niger Delta;
              farther to the east is an 85-km Strand coast where mangrove fronts the sea in the
              extreme eastern corner.

                   A common feature of these geomorphic zones is their low-lying nature. Most
              areas along these zones are less than 3 m in elevation. The beach ridges on the
              barrier islands that rim much of the coastline constitute the highest grounds

                                                     50









                                                                                        Awosika, et al.





                                              n City                          Enuqu



                                  '77
                                   '7 -1


                                     'A7
                                      'P7










                       HILLY COUNTRY
                 [Ma   DRY FLAT COUNTRY
                       DRY LAND & SWAMPS                A
                 M     FRESH WATER SWAMPS
                 MM    MANGROVE SWAMPS
                       ESTUAR;ES
                 eM    BEACHES AND BAR$                                        0             100 km
                 Q=    MARINE                                                  -


            Figure 1. Sketch map showing the main physiographic features             of the coastal and
            adjacent   land areas (after Short and Stauble, 1967).
                         @Logos
                                                        Benin
                        460 BARRIER- LAGOON
                               COAST
                       A                                 Wurri


                                                                        Port           Cot
                             N                                         Harcourt
                                                  100 60                C              I
                                                                              0        0
                                                                              E


                               0    so                            DEL.TA
                                L---J
                                 KM

                                                                        7*

            Figure 2.     Map of coastal Nigeria showing main           geomorphic   units (after Ibe,
            1988).

                                                          51










               West Africa

               with elevation of 2-3 m. In the transgressive mud coast, elevations of less than
               I m are common.

                   An important feature of the Nigerian coastal zone is that it is part of an
               actively subsiding geosyncline. A sequence of dead coralline banks in shallow
               waters off the Nigerian coast indicates stages in subsidence or rise in sea level
               during the past 4,000 years (Allen and Wells, 1962). More specifically, Burke
               (1972) has proposed that all the subsidence (approximately 80 m in about 15,000
               years in the northwestern flank of the Niger Delta) can be accounted for by
               eustatic sea level rise and isostatic adjustment to water load.     The Nigerian
               coastal geosyncline is subsiding not only because it was formed in an area of
               subsidence but also because of the continued dewatering and compaction of its
               sediments that were deposited rapidly. The present rates of subsidence are being
               studied by the authors.    The only reliable figures available to date reveal
               subsidence rates of more than 2.5 cm/yr at the site of a tank farm along the
               deltaic coast, after correcting for loading effects caused by the oil in the
               tanks (Pender Awani, personal communication, 1987).

               Socioeconomic Setting

               Settlement and Population

                   The Nigerian Coastal zone comprises all of the Lagos, Rivers, Cross River
               and Akwa-lbom states and the large southern sections of the Ogun, Ondo, Bendel,
               and Imo states (Nigeria consists of 21 states).

                   Recent population projections indicate that up to 30 percent of the
               estimated 100 million people in Nigeria live in the coastal zone with population
               densities of more than 400 persons per square kilometer in urban centers like
               Lagos, Warri, Port Harcourt, and Calabar (Nigeria in maps, 1982). Most of these
               urban centers are also port and industrial cities, which accounts for their
               teaming populations.    Lagos alone is thought to harbour about 8 million
               inhabitants. Most of those urban centers are literarily bursting at their seams
               with the continued rural-urban drift of the population.

                   Apart from the large urban centers, several important historical settlements
               like Badagry, Forcados, Brass, Abonema, Opobo, and Duke Town, with enduring
               monuments of early European contacts and trade, are located on or near the coast.
               Populations reaching 150 persons per square kilometer are typical of these
               settlements.  Oil exploration and exploitation activities in the coastal zone
               have given rise to sprawling coastal settlements at Escravos, Brass, Bonny, and
               Ibeno-Eket, and several fishing and trading settlements, smaller in size but no
               less significant in socioeconomic terms, dot the coastal zone.      Some of the
               fishing settlements now house fishing terminals with a large work force.

               Communications

                   Apart from a fledgling inland port at Onitsha, all other ports and harbors
               in Nigeria are located naturally in the coastal zone.      These ports at Lagos
               (Apapa and Tin Can), Warri, Port Harcourt, Calabar, Sapele, Bonny, Burutu, Onne,

                                                      52









                                                                            Awosika, et a7.

           and Koko constitute the economic lifeline of the country supporting a hitherto
           flourishing import-export trade. Many canals, creeks, and rivers in the coastal
           zone, particularly in the Niger Delta, provide sometimes the only communication
           links between coastal towns and settlements on the one hand and between these
           towns and settlements and the hinterlands on the other hand.          This water
           transportation system is vital to the country's economy in terms of passenger
           traffic and goods haulage.

                Of the four functional international airports, only Aminu Kano International
           Airport, located at Kano to the north, is outside the coastal zone; the other
           three airports are at Lagos (Ikeia), Port-Harcourt, and Calabar. These airports
           constitute a rapid link with the outside world and account for heavy movements
           of persons, goods, and services to and from Nigeria. Many other local airports
           and helipads in the coastal zone provide easy links to these large airports.

                The terminals of many road and rail systems in the country are located in
           the coastal zone. Besides very important cross-country roads, transport networks
           criss-cross the coastal zone; in some cases, these are the only links between the
           western and eastern regions of the country.

           Agriculture

                The coastal zone proximal to the sea is not fit for agriculture because of
           the high salinization of soils and aquifers. Beyond the present limits of direct
           marine influence are vast agricultural lands afforded by the floodplains of the
           Niger Delta and its numerous distributaries. The major staples of Nigeria (such
           as yams, cassava, plantains, and rice) flourish on these lands, earning the
           coastal zone the nickname "food basket of southern Nigeria"; most of the produce
           has found a favorable export market in West and Central Africa. A planned World
           Bank-assisted swamp rice cultivation project will further boost food production
           from the coastal zone.

                The coastal zone 4as been found to be a highly suitable area for mariculture
           and aquaculture techniques to enhance natural fish production.            Although
           production from captive breeding currently only modestly contributes to overall
           fish production from the coastal zone, projections conservatively place the
           productive potential from future fish farming at a significant 175, 150-525,000
           tons annually (Talabi and Ajayi, 1984).

           Industries

                Nigeria has well over 2,000 industrial establishments, about 85 percent of
           which are concentrated in the coastal zone. The coastal cities of Lagos, Warri,
           and Port-Harcourt are centers of heavy industry; products and activities include
           iron and steel, automobile assembly, textiles, pharmaceuticals, cement, soaps and
           detergents, paints, refined petroleum products, electronics, tires, plastics,
           brewing, beverages and tobacco, and wool and wood products.     About 75 percent
           Nigeria's manufacturing industries are located in Lagos and its environs. Warri
           and Port-Harcourt have two of the country's three petroleum refineries and two


                                                   53










             klest Africa

             of its three petrochemical industries. Warri hosts one of Nigeria's two iron and
             steel industries.

                  In both economic terms and physical layout, the oil industry dominates the
             coastal zone (Figure 3).      Oil production and export handling facilities,
             including structures associated with the ongoing liquefied natural gas project,
             dot the coastal zone with constellations at Escravos, Forcados, Warri, Brass,
             Bonny, and Ibeno@Eket.

                  Elsewhere along the coast, local and small-scale industries like wood works,
             ceramics, weaving and, boat building flourish around coastal settlements.

             Natural Resources

                  The Nigerian coastal zone has abundant natural resources of great
             socioeconomic importance. These resources include forests and wildlife, a vast
             fishery, minerals (including oil and gas), and surface and ground water.

             Forests and Wildlife

                  The natural vegetation along the Nigerian coastal zone consists mainly of
             strand vegetation consisting of Halophyllons, coastal thickets, and forest in the
             area immediately adjacent to the beaches. Mangroves grow in the lower Niger and
             the northwestern flank of the Niger Delta. The mangrove forests alone cover more
             than 9,000 square kilometers. The mangrove swamps serve as spawning and breeding
             grounds for most of the finfish and shellfish resources in the coastal zone.
             Swamp and riparian forests are found along the western region, in the upper Niger
             Delta, and also fringing the banks of the Niger up to Onitsha. Forest reserves
             exist on barrier-bar islands between the Benin and Forcados River estuaries and
             east of the Cross River estuary; these reserves form the raw materials for the
             timber and plywood industries based in Sapele and Calabar as well as for the
             paper and pulp industries in Iwopin and Iku-Iboku. Other natural forest products
             within the coastal zone include thriving wildlife (locally, "bush meat"), which
             boosts the protein availability , as well as palm oil, fuel wood, and south palm
             wine and its derivatives. Apart from helping to meet the protein needs of the
             country, the forest is the home of biologically diverse fauna and flora,
             including medicinal herbs, that provide a source of scientific interest and
             tourist fascination.

             Fisheries Resources

                 Nigeria's coastal zone is blessed with lagoons, creeks, estuaries and, of
             course, the shallow inshore ocean, which constitute a major source of the fish
             and fisheries products sought by artisanal fishermen.

                 Before the advent of the oil industry in the late 1950's the coastal zone
             served as a base for much of the country's artisanal fisheries. Myriad fishing
             settlements established on protected, better drained land or on stilts in river
             estuaries and beaches were, and are still, the dominant feature of the well-
             watered coastal zone. The artisanal fishermen and women who harvest fish,

                                                    54









                                                                           Awosika, et al.



















          Figure 3.    The lowland muddy coast of the Niger Delta with        oil handling
          facilities in the background.


          shrimps, and molluscs in the fresh, brackish, and immediate marine waters with
          set nets, traps, and other passive gear, use crafts ranging friom paddled dugouts
          to motorized large canoes. Ajayi and Talabi (1984), based on earlier surveys by
          Tobor et al. (1977) and others, have estimated the annual yield of the coastal
          and brackish water artisanal fisheries to be between 128,000 and 170,000 metric
          tons. The coastal zone remains the base for this artisanal fishery.

               Bonga (Ethmalosa fimbriata), sardines (Sardinella madarensis = Sardinella
          eba = Sardinella cameronensis), and shad (Ilisha africana) are the principal
          pelagic and semipelagic components of coastal artisanal fishery. The demersal
          component of this fishery targets croackers (Pseudotolithus elongatus, f!. lypus,
          and P. senegalensis), catfish (Aurius spp.), sole (Cynoglossus spp.), shinynose
          (Polydactylus ouadrifilis), grunters (Pomadasys spp.) snappers (Lutlanus spp.),
          and groupers (Eginephelus spp.).     Large tarpons (Megalops atlantica), bill
          fishes, sharks, and rays are also caught.      Shellfish harvested by artisanal
          fishermen include white shrimps (Nematopalaemon hastatus = Palaeinon hastatus),
          brackish prawn (Macrobrachium machrobrachion), river prawn (Macrabrachium
          vollenhovenii), and juvenile pink shrimp (Penaeus notialis =Penaeus duorarium).
          The mangrove oyster, Crassostrea gasar, and other molluscs, e.g., Pachyacllion,
          are delicacies in high demand.

              Artisanal fishery revolving around the above-listed resources not only
          contributes to the nation's march toward self-sufficiency in its protein needs
          but also provides, particularly in the case of shrimps and oysters (annual
          production approximately 48,000 tons, exportable resources with high foreign
          exchange earning potential. For example, one metric ton of prawns fetches 12,000
          U.S. dol I ars. The mangrove swamps serve as the breedf ng and nursery grounds for

                                                 55










               West Africa

               most of the finfish and shellfish resources that are the targets of artisanal
               fishery.

                    The potential of industural fishery within inshore waters is also very high
               (Talabi and Ajayi, 1984; Tobor et al., 1977).

               Minerals

                    Nigeria's coastal zone is richly blessed with a variety of minerals. Large
               deposits of crude oil have been discovered both on land and offshore,
               particularly in the Niger Delta. Nigeria is the sixth largest producer of crude
               petroleum oil in the world and the second largest produces in Africa. Nigeria's
               production capacity reached 2.3 million barrels per day in the late seventies but
               declined to 1.3 million barrels per day as a result of present OPEC restrictions.
               Despite this decline, petroleum still accounts for more than 90 percent of the
               country's exports and foreign exchange earnings.

                    Natural gas has also been found in the Niger Delta in commercial quantities
               either alone or in association with crude oil. At present, about much of the gas
               is flared as there are no large gas utilization projects in the country.
               Projected investments in the planned liquefied Natural Gas (LNG) project will
               further increase the importance of petroleum to the national economy.

                    Other    mineral   resources    such    as   limestone   and    valuable    mineral
               concentrations have been reported along the sandy beaches of Nigeria; these
               provide raw materials for some coastal industries (Ibe, 1982; The and Awosika,
               1986).    Coal and lignite occur in the eastern sector of the coastal zone,
               particularly east of the northern tip of the Cross River estuary.

               Surface and Groundwater

                    Some decades ago, based on folklore and meager records at the University of
               Agriculture and Water Resources, surface water (rivers, creeks, etc.) supplied
               the freshwater needs of the coastal zone apart from the director impact of the
               sea.   But all that has changed, and groundwater is now one of Nigeria's most
               important natural resources, especially in the coastal areas. The coastal zone
               is heavily dependent on groundwater because of the increasing salinization of
               waters of the lagoons, creeks, rivers, and estuaries. The water table is often
               less than 9 m near the coast, and varies from 15 m to 39.6 m farther inland. The
               groundwater potential of this zone is very high (with a yield several hundred
               thousand gallons per hour), due to generally high permeabilities, considerable
               thicknesses of the aquifers, and high recharge potentials attributable to heavy
               rains.

               Present Erosion and Flood Situation

                    Analyses of historical hydrographic charts and aerial photographs, as well
               .as data from ongoing research by the Nigerian Institute for Oceanography and
               Marine Research, reveal widespread erosion and flooding along the entire national
               coastline.

                                                          56









                                                                             Awosika, et al.

                 Present typical rates established at erosion monitoring stations include
            more than 18 m at Ugborodo/Escravos, 20 m at Forcados, 16-19 m at Brass, and 10-
            14 m at the Imo River entrance (Ibe and Antia, 1983 a, b; Ibe, 1984a, b, c,
            1985a, b, 1986, 1987a, b, c; The et al., 1985a, b, c; The and Awani, 1986; The
            et al., 1986a, b; The and Awosika, 1986; The and Murday (In Press); Oguara and
            The (in press); Stein et al., 1986; Ibe, 1988a, b). Some of these rates are so
            erratic and out of proportion with historical rates that sea level rise is
            thought to be a part of the problem (Ibe, 1988). An acceleration of the rise in
            sea level would further exacerbate the situation.



            EFFECTS OF SEA LEVEL RISE ON THE COASTAL ZONE

            Increase in Beach Erosion Rates

                 Although the amount of sea level rise totals a few millimeters per year and
            may seem small, it plays a big role in explaining erosion processes affecting
            most of the low-lying coastline in the world, particularly in Nigeria. Though
            rising sea level does not cause beach erosion per se, other more important causes
            are waves, winds, longshore currents, tidal currents, low relief, shelf width,
            subsidence, sediment characteristics, offshore topography, and human impact. The
            seriousness of sea level rise with respect to increased erosion and flooding can
            be deduced from the data of Bruun (1977), which showed that a sea level rise of
            0.3 m (I foot) would cause a shoreline recession of more than 35 m (100 feet).
            This may even translate to higher values on low-lying areas typical of the
            Nigerian coastal zone.

                 A rise in sea level of approximately 1 m, which here will be accentuated by
            the phenomenon of subsidence, would aggravate the existing ecological problem
            of coastal erosion, resulting in loss of wetland and creating a threat to all
            installations on or near the coastline.

            Flooding

                 A rise in sea level will result in flooding of the low-lying beaches. This
            will automatically cause flooding in the adjacent coastal areas.         This is
            expected to become even more threatening whenever storm surges coincide with
            spring tides.

                 Many of these barrier islands defend the rich low-lying coastal lands
            against storms; they enclose and protect the rich low-lying resources of
            estuaries, marshes, and mangroves, all which are highly vulnerable to flooding
            resulting from sea level rise.

                 Many of the barrier island, e.g., Victoria Island, Ikoyi Island, are heavily
            developed and urbanized, with most state capitals and settlements situated near
            the coast. Flooding of these urban area will result in destruction of properties
            and loss of income and lives. Many industries and oil-handling facilities built
            near the coastline, particularly in the Niger Delta, will also be affected by
            flooding.

                                                   57










              klest Africa

                   With rising sea level of approximately I m, the potential for flooding and
              erosion of certain key transportation arteries on barrier islands and others near
              the coast will increase. This will lead to a degeneration or interruption of
              emergency and other social services. With higher sea levels, existing fishing
              facilities, such as jetties, and storage centers built on the coastal fringes
              only a couple of feet above the mean high tide line will' be subjected to more
              frequent tidal and storm inundation. The growing coast based-tourism will be
              heavily affected as a result of both increased rates of erosion and persistent
              flooding (Figure 4).


















                                                                         K-1 PRI
                                                                              "M


              Figure 4.  Tourist and recreational scene on a    beach on Victoria Island with
              hotels in the background.


              Subsidence

                   The effects of sea level rise will increase as a result of ongoing
              subsidence.

                   The Nigerian coastal geosyncline, particularly the Niger Delta, is sinking
              not only because of tectonic subsidence but also because of continued dewatering
              and compaction of sediments that were rapidly deposited.

                   The authors are studying the present rates of subsidence. The only reliable
              figures available to data reveal subsidence rates of more than 2.5 cm/year at the
              site of a tank farm along the delta coast, after correcting for the loading
              effects of the oil in the tanks (Pender Awani, personal communications, 1987).

                   Human intervention in the coastal zone (e.g., fluid extraction) has tended
              to accelerate the subsidence problem. Subsidence associated with withdrawal of
              fluids results in the reduction of fluid pressure in the reservoir or aquifer,
                              4
                                       gr











































                                                     58









                                                                           Awosika, et al.

          thus leading directly to an increase in "effective stress" (or "grain to grain
          stress") in the system. Compaction results, and basin subsides.

          Saltwater Intrusion and Higher Water Tables

               The depth to water-table in the coastal zone is often very shallow, and the
          groundwater itself is subject to pollution and saline contamination from
          seawater. Sweet water in the area is, however, contained in the deeper aquifer,
          which probably is in hydraulic continuity with the coastal plain sands.

               Many towns and cities situated on the coastal lowlands obtain their water
          supplies from the enormous groundwater resources of this hydrogeological
          province. Some municipal wells in Port Harcourt yield as much as 90,000 gallons
          per hour. A global sea level rise is expected to raise the water table along the
          coast and result in increased salinity of the groundwater.

          Deforestation

               The Nigerian coastal zone is endowed with an extensive and productive
          mangrove ecosystem, particularly in the Niger Delta.

               Vast and fertile river floodplains have made the delta and other parts of
          the coastal zone the food basket of southern Nigeria.      Rising sea level will
          increase the salinity of the water and soil. Such plants that are not tolerant
          to this increased salinity will die. Scenes of dying vegetation are now common
          along the Mahin mud beach where saline waters have flooded the adjacent low-lying
          coastal areas.

               This has resulted in the complete decimation of the once-flourishing rain
          and mangrove forests (Figure 5). The lumber industry in Spele is expected to
          suffer from the deforestation resulting from increased salinity attributable to
          global sea level rise.

          Transportation and Communication

               Owing to the booming economic activities, an extensive network of roads
          (about 4,000 km in Bendel State, 2,500 km in Rivers State, and the new 65-km
          Lagos to Epe dual highway built on the Lekki barrier island) has been developed,
          while extensive creeks, channels, rivers, and estuaries provide an excellent
          water communication and transportation network. Increasing sea level will result
          in flooding of these transportation and communications networks.

               The state government canals linking the numerous settlements along the Mahin
          mud beach are close to being overtaken by the ocean (Figure 6). This could be
          disastrous to tertiary institutions, hundreds of secondary schools, commercial
          houses, hospitals, hotels, and other institutions in which billions of naira have
          been invested.





                                                  59










             West Africa

























             Figure 5.  Trees dying as  a result  of saltwater intrusion.

             Ocean Dynamics

                  It has been suggested that sea  level rise will cause a continued deepening
             of the Continental Shelf   beyond the depth of closure and will result in an
             increase of effective wave height due to the reduction in bottom friction as a
             result of greater depth.

                  It is hence to be expected that the present ocean dynamics (wave height,
             period, length, breaker angle, longshore current direction and magnitude, etc.)
             shaping the coastal zone will change.       A change or modification of ocean
             dynamics, particularly the nearshore dynamics, will affect the sedimentary fluxes
             and hence sedimentary budget.    This controls the coastline evolution through
             erosion, accretion, or stability. These modifications will vary from place to
             place, depending on whether the changing dynamics will result in erosion,
             accretion, or stabilization.    These impacts could be further exacerbated if
             storms become more frequent, or winds and currents change.


             POSSIBLE RESPONSES

                  The possible measures that can be taken to mitigate the impacts of sea level
             rise on the Nigerian coastal zone can be classified according to whether the
             measure will attempt to halt the approach of the sea, i.e., "no retreat"; whether
             the measure will allow the sea to rise while avoiding the impacts, i.e.,


                                                    60









                                                                            Awosika, et a7.



















          Figure 6. The Niger Delta is already experiencing    flooding problems which will
          only be made worse by sea level rise.


          (11retreat"); or whether the measure will be an attempt to   cope with sea level
          rise ("adaptation").

          "No Retreatu Measures

               "No retreat" measures include construction of the following:

               1.    Levees, seawalls and revetments, which basically protect the shoreline
                     from waves and floods; and

               2.    Construction of groins and breakwaters to act as a wave barrier; this
                     results in a zone of reduced wave energy, and also helps to trap
                     sediments.

               Generally the "no retreat" measures are very expensive for a developing
          country like Nigeria with huge external debts. Examples from other countries
          where these "no retreat" measures have been attempted have shown that they have
          not worked effectively and, in some cases, have exercabated the erosion and flood
          problem. Again, these "no retreat" measures are not capable of abating other
          impacts of sea level rise such as higher water tables and saline groundwater
          intrusion.

          "Retreat" Measures

               "Retreat" measures are generally soft regulatory and policy measures that
          generally do not require large and immediate expenditure. These measures are
          also flexible and can be easily changed in response to new sea level rise data.

                                                  61










              West Africa

              However implementation of such of measures results in the loss of land. Retreat
              measures include the following:

                   1.    Set back line:   A set back line is a predetermined l'imit along the
                         coast seaward to which no settlements or facilities should be located.
                         The et al. (1984) suggested a set back line of 20 times the determined
                         rate of erosion.

                   2.    Beach nourishment program: This method is a popular approach used to
                         protect coastal property and to maintain recreational beaches.
                         However the success of beach nourishment programs depend on correct
                         implementation procedures, i.e., choosing the right grain size, burrow
                         pit, etc. The many beach nourishment programs implemented at the Bar
                         beach during 1974-75, 1981, and 1985-86 have not very successfully
                         checked erosion and flooding.     This was partly due to incorrect
                         implementation procedures.

                   3.    Controlled urbanization and caRital facilities: The coastal zone of
                         Nigeria has witnessed sporadic urbanization in the 20 years due to the
                         oil boom of the seventies. Efforts should now be made to control this
                         urbanization within the coastal zone.       Construction of capital
                         facilities such as roads, buildings, sewers, etc., should be kept
                         beyond the reach of projected sea level rise.

                   4.    Public awareness program: Measures to increase public awareness of
                         the potential impacts of sea level rise should be pursued. Private
                         developers should be enlightened on the foundation and structural
                         codes required for buildings in such unstable zones along the coast.
                         Illegal mining of beach sand should also be discouraged. These san
                         miners should be made aware of the danger they create by their
                         actions.

                   5.    Increase in flood plan elevation: Efforts should be made to increase
                         the elevations of the floodplain or beach ridges around the many
                         barrier islands. This would help to reduce the potential of flooding
                         of the adjacent lowland, but preliminary studies show that this is an
                         expensive option.

                   6.    Afforestation:  Limiting deforestation and using reforestation and
                         afforestation to slow or stop the rise in atmospheric concentration
                         of carbon dioxide was first proposed during the 1970's. Today it is
                         accepted as one of the effective ways of slowing down erosion and
                         denudation of the land. Efforts to afforest the coastal zone should
                         be stepped up, while deforestion should be discouraged.

                   7.    Studies: Since rising sea level affects all coastal areas, studies
                         must be initiated with the aim of identifying area that will be very
                         sensitive to impacts of sea level rise.    These studies should also
                         include collecting data on water level, rates of erosion, subsidence,
                         groundwater, ocean dynamics, and other facets of coastal management.

                                                     62









                                                                               Awosika, et al.

                     Such studies must be viewed by government and other sponsoring
                     agencies as essential and not as an academic exercise.


          CONCLUSION

               Nigeria does not presently have a well -articulated, concrete and enforceable
          coastal zone management policy. The lagoon city project, which was intended to
          create prime real estate on the foreshore of the Lagos lagoon but instead led to
          enormous ecological damage, took advantage of this lack of a coherent policy.
          An urgent need exists for national policies with adequate legal provisions for
          coastwide, coordinated, and effective management and control of the Nigerian
          coastal zone.



          BIBLIOGRAPHY

          Allen, J.R.L.     1964.    The Nigerian continental margin: bottom sediments,
          submarine morphology, and geological evolution. Marine Geology 1: 289-332.

          Al 1 en, J. R. L. 1965a.     Late Quaternary Niger delta, and adjacent areas:
          Sedimentary environments and lithofacies. A.A.P.G. Bull 49: 547-600.

          Allen, J.R.L., and Wells, J.W. 1962. Holocene coral banks and subsidence in the
          Niger Delta. J. Geol. 70: 381-397.

          Ajayi T.O., and Talabi, S.O. 1984. The potentials and strategies for optimum
          utilization of the fisheries resources of Nigeria. NIOMR Tech. Paper No. 18.

          Atlas of the Federal Republic of Nigeria. First Edition 1978. Lagos.

          Bruun, P.     1977.   Practical solution to a beach erosion problem.           Coastal
          Engineering 1: 3-16.

          Burke, K.     1972.   Longshore drift, submarine canyons and submarine fans in
          development  of Niger Delta. AAPG Bull. 56: 175-1983.

          Ibe, A.C.    1984a.   Defending Victoria Island against sea incursion.         Special
          Report, Lagos, Nigeria: Federal Ministry of Education, Science and Technology,
          7 p.

          Ibe, A.C. 1984b. Protecting Victoria Island against sea incursion. A position
          paper submitted to the Ad Hoc Committee on the Victoria Island Erosion Problem;
          August 1984. 5p.

          Ibe, A.C.    1984c.   A rational strategy for defending Victoria Island against
          oceanic surges. In: Proc. Conference on the Bar Beach Surge. Federation of
          Building and Civil Engineering Contractors of Nigeria Ltd.



                                                    63










             West Africa

             Ibe, A.C.    1985a.   Nearshore Dynamics and Coastal Erosion in Nigeria.          Paper
             presented at the UNESCO Expert Workshop on WACAF/3 Project; Dakar, Senegal ; March
             11-19, 1985.

             Ibe, A.C. 1985b. Harbor development related erosion at Victoria Island, Lagos.
             First International Conference on Geomorphology, University of Manchester,
             England; September 15-21, 1985.          In:    International Geomorphology 1986.
             Gardiner, V., ed. pp.165-181.

             Ibe, A.C.    1986.   Port development related erosion at Escravos, Bendel State,
             Nigeria. In: Proc. Man's Impact on the Coastal Environment Barcelona, Spain,
             6-13 September 1986.      In:    Thallasa, Revista De Ciencions Del Mar Special
             edition. Villas, F., ed.

             Ibe, A.C.     1987a.   Marine erosion on a transgressive Mud Beach in Western
             Nigeria.    In:    Proc. Intern. Symposium on Geomorphology and Environmental
             Management, Alahabad; India, Jan. 1-20 eds.         S. Sighn and R. C. Tiwari (in
             press).

             Ibe, A.C.    1987b.   Collective response to erosion hazards along the Nigerian
             Coastline. In: Proc. Coastal Zone, 1987. Seattle, Washington: pp. 741-754.

             Ibe, A.C. 1987c. Human Impact on the coastal erosion problem in the west and
             central Africa (WACAF) region.         In:    Proc. International Se Conference,
             University of Mauritius, Reduit, Mauritius, 7-12 September 1987 (in press).

             Ibe, A.C., and E.E. Antia. 1983a. Preliminary study of the impact of erosion
             along the Nigerian coastline.       In:   Proc. First International Conference on
             Flooding, Desertification and Erosion in Africa. Port Harcourt, Nigeria: Rivers
             State University of Science and Technology, May 2-6, 1983.

             Ibe, A.C., and E.E. Antia.       1983b.   Preliminary assessment of the impact of
             erosion along the Nigerian shoreline. NIOMR Tech. Paper No. 17p.

             Ibe, A.C., and P.E. Awani. 1986. Erosion management strategies for the Mahin
             Mud Beach, Ondo State. In: Proc. National Seminar on Flooding and Erosion along
             the Nigerian Coastline. University of Lagos, May 1986.

             Ibe, A.C., and L.F. Awosika. 1986. Sedimentology of the barrier bar complexes
             in Nigeria. NIOMR Tech. Paper No. 26.

             Ibe, A.C., L.F. Awosika, and E.E. Antia. 1984. Progress Report No. 2. Coastal
             Erosion Research Projects. NIOMR Special Publications; 106p.

             Ibe, A.C., L.F. Awosika, A.E. Ihenyen, C.E. Ibe, and A.I. Tiamiyu.               1985a.
             Coastal erosion at Awoye and Molume, Ondo State, Nigeria. A report for Gulf Oil
             Company (Nigeria) Ltd. 123p.




                                                       64










                                                                                Awosika, et al.

         Ibe, A.C., L.F. Awosika, A.E. Ihenyen, C.E. Ibe, A.I. Tiamiyu, E.C. Okonya, and
         T. Orekoya. 1985b. A study of currents and scouring effects at the proposed
         Davy Banks 'Al Location in OML 14.        A report for Shell Petroleum Development
         Company of Nigeria Ltd. 56p.

         Ibe, A.C., L.F. Awosika, C.E. Ibe, A.I. Tiamiyu, F.O. Egberongbe, and S. Orupabo.
         1986.    The erosion problem at Victoria Island (1900 to Present) and its
         solutions.     In:   Proc. National Seminar on Flooding and Erosion along the
         Nigerian and   similar coastlines. University of Lagos, May 1986.

         Ibe, A.C., A.E. Ihenyen, and C.E. Ibe.        1985c.   A hydrographic Survey of the
         Proposed Benin Estuary Location OML 43. A report for Shell Petroleum Development
         company of Nigeria Ltd. 25p.

         Ibe, A.C., and M. Murday. 1986. Aerial Photostudy of recent migration of the
         Lagos shoreline. NIOMR Techn. Paper (in press).

         Stein, D., G. Echwebber, and A.C. Ibe. 1986. Investigation on the Bar Beach
         erosion and a proposal on the maintenance of the coast.           National Seminar on
         Flooding and    Erosion along the Nigerian and related coastlines.           May 1986,
         University of   Lagos.

         Oguara, T.M., and A.C. Ibe.       Decision Analysis for the selection of erosion
         control measures. NIOMR Tech. Paper (in press).

         Nigeria in Maps, 1982.      Barbour, K.M., Oguntoyinbo, J.S., Onyemelukwe, J.O.C.,
         and Nwafor, J.C., eds.

         Tobor, J.G., M.O. Okpanefe, J.0. Oladoye, A.L. Ekwemalor, and 0. Oladip. 1977.
         Fisheries Statistical Survey of Nigeria. Report 1975-1976 NIOMR, Lagos.




















                                                    65











                RESPONSES TO THE IMPACTS OF GREENHOUSE-INDUCED
                                 SEA LEVEL RISE ON SENEGAL


                                      PROFESSOR ISABELLE NIANG
                        Departement de Geologie, Faculte des Sciences
                                    Universite Cheikh Anta Diop
                                         Dakar-Fann, Senegal






           ABSTRACT

                The predicted rise in sea level of I m from greenhouse- induced global
           warmi ng wi 11 greatl y i mpact the country of Senegal . The coastl i ne of Senegal i s
           made up of three large estuaries (Senegal, Saloum, and Casamance Rivers), about
           400 km of sandy coastline, and approximately 70 km of rocky cliffs. The low-
           lying estuarine areas will be prone to inundation, and the sandy coasts will most
           likely experience increased erosion if sea level rises as predicted. The Cap
           Vert peninsula, where the majority of the population and economic activity are
           concentrated, will be greatly affected.       Furthermore, Senegal relies upon the
           coast for the income generated from agriculture, fisheries, industry, and
           tourism. Coastal towns and cities, like Dakar, Saint-Louis, Rufisque, Mbour, and
           Joal, will be required to retreat and/or stabilize their waterfronts.


           IMPLICATIONS OF SEA LEVEL RISE

                Senegal would be very vulnerable to a rise in sea level, because low-lying
           beaches and estuaries account for approximately 90% of its 700-km coast.
           Increased coastal erosion would be particularly severe in areas that are already
           eroding, such as Saint-Louis, Rufisque, and Joal, and homes would almost
           certainly be destroyed. Coastal wetlands, including tidal flats, mangroves, and
           tannes would be flooded, upsetting fish and wildlife. Saltwater intrusion into
           both groundwater and agricultural lands would increase. Sand spits would breach
           more often, and roads and other infrastructure would be lost.

                Because two-thirds of the nation's population and 90% of its industry is in
           the coastal zone, the nation cannot afford to ignore this issue, nor should
           coastal cities and towns.      The authorities are aware of the importance of the
           coastal zone, but not about the possible acceleration in sea level rise. It will
           be necessary to coordinate efforts among authorities, scientists, educators, and
           industry leaders, who should all consider the national well-being to be of
           highest priority. An action plan is required that would include:

                                                     67











               West Africa


                    1.  Scientific monitoring of the coastal zone (e.g. beaches, estuaries,
                        mangrove, groundwater evolution . No tide data have been recorded since
                        1964. A network of tide gauges should be established. Swell monitoring
                        and regular morphological and sedimentological profiles should be
                        continued.

                    2.  Education of the entire nation about sea level rise and its conseguences
                        through a major public information campaign.          This is especially
                        critical in a nation of diverse ethnic groups who     have long histories
                        of living and working in ancestral grounds. For example, at Rufisque,
                        the Lebou fishermen refuse to leave even when their homes are inundated,
                        because these are ancestral grounds. In other areas, sand miners need
                        to learn the consequences of their removing sand from eroding coastal
                        areas, but perhaps more important, they need to learn other occupations
                        that would provide an acceptable livelihood for them and would be
                        harmless to the environment.

                    3.  Revision or creation of strong and consistent national policies for use
                        of the coastal zone. This would enhance uses of the coastal zone and
                        would avoid future problems of inappropriate siting of industries or
                        populations.

                    4.  Creation of response strategies to a rise in sea level.          Developing
                        countries such as Senegal find it very difficult, if not impossible, to
                        invest in hard coastal protection works, or even those such as beach
                        renourishment. Other options will have to be developed for inclusion
                        in the national policy.

                    5.  Programs to cope with potential relocation of communities, and possible
                        retraining of people for new skills or occupations.           For exampl e,
                        artisanal fisheries or even certain agricultural activities might be
                        changed to mariculture or aquiculture.      Strong tribal or ethnic ties
                        that exist in some traditional communal villages on the coast will have
                        to be considered in any relocation and retraining activities.

                    6.  Programs to develop and encourage new industries, or agricultural
                        activities to replace others displaced by the effects of sea level rise.
                        For example, in the Casamance River valley perhaps some peanut and
                        millet growing might be replaced by more rice growing, which already
                        exists. Saltworks at Kaolack on the Saloum River have the potential to
                        increase.

                    In the absence of detailed studies, it is impossible to be any more specific
               about the effects and responses to a rise in sea level.                Nevertheless,
               considerable knowledge about the coast of Senegal has accumulated. To give the
               reader an idea of the environments at risk, the following sections describe the
               nature of the coastal environment, the impacts of current changes in sea level
               and climate, and the socioeconomic resources of the coastal zone.         Geological
               details about the coast are found in the appendix.

                                                        68









                                                                                            Niang

          THE COASTS OF SENEGAL

               The three main types of coastlines in Senegal (Figure 1) are rocky coasts
          (about 70 km long), sandy coasts (about 400 km long), and mangrove estuaries
          (about 250 km).

          Rocky Coasts

               These coasts are located along the Dakar and Ndiass horsts.             Generally,
          their base is covered by blocks, cobbles, and pebbles, which protect them from
          wave attack. There are often small bay beaches between adjacent rocky capes.

          Sandy Coast

          The North Coast or "Grande Cote" (Saint-Louis to Yoff)

               Here, the straight sandy beaches are linked with three Quaternary dune
          systems:   (1) the continental "red dunes," which are about 20 m high; (2) the
          yellow dunes, which form a 250- to 4,500-m-wide field that is often 20-30 m high;
          and (3) the littoral white dunes, which range from a few to 100 m wide and vary
          between a few to 25 m high and are still accumulating windblown sand from the
          beach.   The interdunes      (known as "Mayes") are periodically inundated by
          precipitation and  groundwater, and play an important role in the coastal ecology.
          Although they are 3 to 10 m above the sea level, they would be affected by any
          rise in sea level due to the backwater effect.

               The beaches   are relatively narrow (between 40 m at Yoff and 110 m at
          Camberene).    Sall  (1982) suggests that they erode during the dry season and
          accumulate during   the wet season. The Bruun rule suggests that with a rise in
          sea level, the reaccumulation would be less owing to the need for the offshore
          profile to rise with sea level. Given the Bruun rule-of-thumb that a one meter
          rise in sea level causes one to two hundred meters of beach erosion, it is clear
          that even a relatively small rise in sea level could completely eliminate these
          beaches.

          -The South Coast or "Petite Cote" (Hann to Wiffere)

               Unlike the North Coast, the South Coast is characterized by rocky capes and
          the absence of dunes (Demoulin, 1967).       Because the beaches are lined with a
          sandy barrier, however, we consider these areas to be part of the sandy coasts
          (Figure 2). These barriers are often adjacent to shallow lagoons (wadi). During
          the rainy season, these lagoons and wadi have much higher water levels, which
          sometimes causes a barrier to break; this can release substantial organic
          material into nearby coastal waters.

               The beaches are very narrow (30 to 40 m). Beach rocks stick out of the sand
          at the beaches at Rufisque, Bargny-Sienndou, and along the "Pointe de Sangomar"
          sand spit.

               Because the beaches are very narrow, a rise in sea level could have an even
          greater impact here than along the North Coast. In cases where rocky capes lie

                                                    69









                       West Africa

                                                                                                                                                  or


                                                                                                        S ENEGAL


                                                                                                    delt:11



                                                                          St Louis

                                                                        LaaW d
                                                                         Barbori


                                                                                          Louga



                                                                                                                                       Linguere
                                                                                                                                       0

                                                                                  Kebomer







                                            Cap Vert....             Thies


                                                                                               Diourbel
                                              DAKAR
                                           peninsula

                                                          Mbour




                                                                                                Koolock               Koffrine

                                                                   Dii                Saloum
                                                                     fere              estuary
                                                            d e S a n emm-ar




                                                                                    ......  . . . . . . . .


                                                    Rocky coast


                                            r77771
                                                    Sandy coast


                                                    Mangrove estuary




                                                                                                                                      Koldo 0
                                                              Presw'ilt
                                                         aux olseou               Cosomonce
                                                                                    estuary
                                                                                         C  S   ,@Ce
                                                                  Diogue
                                                                                             Ziguinchor
                                                                         =--7-
                                                                          :7-                                0               50                loolus
                                                              Cap Swring

                     Figure 1. Main coastal types of Senegal.

                                                                                      70







                                                                                           FS's."Zil                                                 Wang

                                                                                                  10,




                                                                    SL Louis
                                                                                IV





                                                                      10


















                                    Dakar










                                                                                                --am



                                                                                      stuary








                                                                                                 GAMBIE












                                                                                          an-
                                   3 Motor Contour                                  ") estuary
                                                                             %                J
                                   5 Motor Contour                                       am


                                                                                        %
                                                                                         %,.-   -am
                                                                           %


                                                                                                         0                 so                  1 OOkm


               Figure 2. Map of Senegal showing                              3- and 5-meter contours.

                                                                                    71










              West Africa

              behind the beach, there would be little opportunity for the ecosystem to shift
              landward.

              Mangrove Estuaries

                   These estuaries correspond to the three most important rivers: the Senegal,
              Saloum, and Casamance. All of these estuaries are characterized by tidal flats,
              mangroves, marshes, and tannes.     Moving inland from the tidal channel, one
              observes first tidal flats, then mangrove marshes with,Rhizophora racemosa (5
              to 12 m high) replaced by R. harisonnii and R. mangle in the Saloum estuary, then
              Avicennia africana (1 to 3 m high).     From south to north, owing to climatic
              conditions, we notice a reduction of the mangrove population density and a
              diminution of the species number (six in Casamance, four in Saloum, and two in
              Senegal).   The bare tanne is limited by the annual tide level, whereas the
              vegetated tanne is also found above this tide level but can tolerate inundation
              by freshwater.

                   These estuaries are also characterized by manmade shell deposits resulting
              from the trade of Anadara senilis and the Rhizophora oysters (Gryphea gasar)
              since the Neolithic times.    They are present in the three estuaries but are
              particularly pronounced in the Saloum (Diop, 1986).

                   Studies on the mangrove population along the Saloum (UNESCO, 1985) have
              shown that from the mouth to the upstream part of the estuary, there has been a
              height reduction of Rhizophora, diminution of the area occupied by Rhizophora,
              reduction of the population density, and augmentation of dead Rhizophora.
              Finally, the mangrove disappears upstream of Foundiougne. This regression of the
              mangrove environment will be related to the drought, to the human activities (use
              of trees for cooking, small-scale exploitation of salt), and to natural diseases.


              CURRENT CHANGES IN THE COASTAL ENVIRONMENT

              Consequences of the Drought

                   First of all, there is a renewal of eolian (wind-blown) migration of dunes
              due to recent droughts. Along the Grande Cote, white dunes are migrating toward
              the continent (2 m/year to 7.1 m/year), the exception being the "Gandiolais"
              (south of St-Louis), where the white dunes migrate seaward (11.5 m/year between
              1954 and 1980).    This phenomenon determines a progressive filling up of the
              interdunes (niayes). The migration speed of the yellow dunes varies between 4.80
              m/year in the Cayar-Tanma lake sector to 1.3-3.8 m/year at Vele and Pikine. If
              global warming worsens drought conditions, we may see an acceleration in the rate
              of dune migration.

                   The lack of precipitations also induces a salinization of the rivers, the
              groundwaters, and soils due to the weak or absent freshwater input. Saltwater
              intrusion has led to a decline in the mangroves (in Casamance, 70 to 80yo of the
              mangrove has disappeared since 1969 (Diop, 1986; Marius et al., 1986)).        The
              reduction of the mangrove population is accelerated by human activities such as
              the use of trees for cooking, construction of dams, the rice culture (responsible

                                                      72










                                                                                               Niang

           for 25% of the destruction in Casamance between 1967 and 1982), and the
           exploitation of salt (Paradis, 1986).          Therefore, tannes are replacing the
           mangrove swamps (Marius et al., 1986). For example, between 1973 and 1979, in
           the Casamance estuary, Sall (1982) noted that tannes increased 107 W                while
           mangroves declined by 87 km'.

                Other consequences of the drought are the acidification and oxidation of the
           soi 1 s, wel 1 studied in the Casamance estuary (Boivin et al ., 1986; Mari us et al . ,
           1986). The acido-sulfated soils are characterized by a low pH (<4.5), formation
           of jarosite (iron sulfate), and salt precipitation with appearance of gypsum
           unknown in Casamance before 1972.

                Last, there is a tendency toward salt contamination of the groundwater due
           to the lowering of the groundwater table (Boivin et al., 1986).

                All of these problems could be made substantially worse if global warming
           leads to a drier climate in coastal Senegal. Destruction of mangroves would have
           a particularly severe impact on fishing. The threat to water supplies would be
           particularly    important     for   communities    already    struggling    with     salt
           contamination.

           Coastal Erosion

           Cliff erosion

                The speed of a cliff's retreat depends on its type. The Cap de Naze cliffs
           are retreating slowly (5.8 cm/year) at the base owing to accumulation of blocks
           and pebbles, but five times as rapidly at their summits.          The plunging cliffs
           (Cap des Biches, Fann) are eroding more rapidly, particularly those made of
           sedimentary rocks (32.9 cm/year for the Cap des Biches and 29.3 cm/year for the
           Fann cliffs).

           Erosion Along the Sandy Coasts

                Several parts of the Senegalese coasts are eroding rapidly (DHV, 1979; PNUE,
           1985): St-Louis (1.25 to 1.30 m/year), Rufisque (about 1.30 m/year), and Joal in
           particular. The impacts are important because all of these areas are densely
           inhabited.    Consequently, many coastal defense structures have been built,
           including seawalls at St-Louis, Rufisque, and Joal, and groins at Rufisque
           (Murday, 1986).

                The causes of coastal erosion are still unclear. According to Masse (1968)
           and DHV (1979), the erosion between Mbao and Bargny is induced by a predominant
           onshore-offshore sand transport especially during storms, part of the sands not
           being recovered by the beaches.          This result is consistent with the slow
           continuous rate of sea level rise (a few millimeters per year, Elouard et al.,
           1967). In addition, human activities such as the hardening of the coastline by
           human construction and especially the extensive sand mining along the Cap Vert
           coast (from Cayar to Bargny) are contributing to the problem. Below Bargny, the
           littoral drift also contributes to the problem.        If sea level rise accelerates,

                                                      73










               West Africa

               there is little doubt that erosion would increase proportionately throughout much
               of the-coastal zone.

                    The many sand spits are even more vulnerable, even with current trends.
               From 1850 to 1980, the "Langue de Barbarie" has seen 24 breaks, which forced the
               authorities to stabilize the sand spit. Since then, the breaks have occurred
               only south of St-Louis.     With an accelerated rise in sea level, additional
               protective measures will be necessary.


               SOCIOECONOMIC ASPECTS OF THE COASTAL ZONE

                    About the two thirds of the nation's population (about 6.8 million in 1987)
               is concentrated along the littoral zone. The population density is between 10
               and 20 persons/km' along the North Coast, 20-50 persons/km' in the South Coast
               and Casamance, and more than 1,800 persons/km' in the Cap Vert peninsula. Most
               of the big cities and towns are located along the littoral zone:          St-Louis
               (88,404 inhabitants in 1976), Dakar (about 500,000), Pikine (1 million), Mbour
               (37,896), Joal (15,665), Kaolack (135,473), and Ziguinchor (69,757). Directly
               or indirectly, a rise in sea level would affect all of these inhabitants.

                    The most important maritime fishing centers are, from north to south, St-
               Louis, Cayar, Dakar, Mbour, and Joal. Owing to the seasonal migration of fauna,
               in relation to upwellings, the fishermen migrate from north during the dry season
               to south during the wet season. Estuaries are important centers for nonmaritime
               fishing. The total fish production was approximately 157,000 tons in 1987 with
               a predominance of maritime and industrial fishing.     Part of the production is
               distributed on the great markets, another part is smoked and/or dried, and a part
               is exported. Global warming could upset these fisheries both through the loss
               of wetlands that support estuarine fishing and as a result of changes in ocean
               currents, which could affect maritime fisheries.

                    The main farm crops along the coast are peanuts (total production of 946.4
               thousand tons in 1987) and millet (total production of 801.2 thousand tons in
               1987); the rice culture (total production of 135.8 thousand tons in 1987) has
               traditionally has been confined to the Casamance estuary, but now is also present
               in the Senegal and Saloum estuaries (EPEEC, 1983). Along the North Coast, the
               niayes are used for market gardening, which is also practiced in the different
               estuaries.

                    Since 1950, the Senegal estuary has been subject to management of irrigated
               perimeters; this development program is now enhanced by the Diama and Manantali
               Dams. These projects will permit the irrigation of 250,000 hectares (Michel and
               Sall, 1984). Both sea level rise and changes in precipitation could impair the
               functioning of these new systems.

                    Tourism is extensive on the South Coast (Saly, Mbour, Joal) and in Casamance
               (Cap Skiring, Kabrousse), where it contributes 31 billion CFA francs per year in
               hard currency.


                                                      74







                                                                                       Niang

                          APPENDIX: THE COASTAL ENVIRONNENT OF SENEGAL



         EVOLUTION OF THE COAST

              The configuration and the evolution of the coastline in Senegal have been
         controlled by three main factors:     climate, geology, and hydrodynamics.       We
         discuss each in turn.

         Climate

              Senegal's climate is characterized by the alternation of two seasons:

              6   The dry season: cold, lasting 6 or 8 months during which the N to NW
                  maritime trade winds are dominant all    along the coastline, with some
                  incursions of the NE continental trade wind or "harmattan."

              0   The wet or rainy season:    hot, during  which the precipitation occurs
                  (80% of the precipitation between July   and September with a maximum in
                  August). The wind regime is dominated    by SW monsoon winds.

              The main characteristic of this climate is the great interannual variability
         of the precipitation. The recent drought has been in effect since 1968 (Olivry,
         1983).

         Geology

              The lithology and tectonics are responsible for the great morphological
         subdivisions of the coastline (Sall, 1982).     The entire Senegalese coastline
         belongs to the Meso-Cenozoic Senegal o-Mauritani an passive margin basin (Bellion,
         1987) (Figure A-1).

         Tectonics

              The Cap Vert peninsula is subdivided by N-S to NNE-SSW faults in two horsts
         (Dakar and Ndiass horsts) separated by the Rufisque graben (Elouard, 1980). The
         two horsts constitute the higher parts of the coastline (105 m). From Kayar to
         Mbour three main fault directions (NNE, NW, and NE) have been identified (Dia,
         1980; Bellion, 1987; Lompo, 1987), and these faults appear to have been active
         since the last Pleistocene (Dia, 1980). Furthermore, two subsidence centers are
         located in the Senegal "delta" zone to the north and in the Saloum-Casamance
         regions to the south.    But recent studies (Faure et al., 1980) have shown a
         lithospheric rigidity of more importance than predicted.

         Volcanism

              It is a basic volcanism (Dia, 1980, 1982; Bellion, 1987), subdivided in two
         periods:

                  The Tertiary volcanism (35.5 to 5.3 MA) is fissural (Dia, 1982). In the
                  Cape Verde peninsula, this volcanism determines the "eruptive system of
                  Dakar" (Dia, 1980);

                                                 75








                   West Africa                                                                                           PA*ftr

                                                                                        S E N E G A L_










                                                                St Louis








                                                                                                                 1,Lifiguere

                                                                                               I-T- I -




                                                                                                             oo  a
                                                                                                             ooo

                                                                                                                  o
                                                                                                     o o     ooacQ

                                                                                                             0o
                                                                                                       o     o
                                       DAKAR           +                          -Vidurbel           o      oo
                                                      +                                                          o
                                                                                                             o o
                                                 Mbour                                                 o     ooo
                                                                                                        o



                                                                                    0                 Kaffrine







                                     MTertiary and Quaternary
                                            volcanism
                                     QUATERNARY
                                          Littoral dunes
                                          Fluvio deltaic deposits                       G A M B    E
                                     17-7710golion dunes

                                     TERTIARY
                                     = "Continental Terminal
                                          Nummulite limestones
                                          Sholeslime stones
                                     EM@Lower Eocene
                                     P77'1 Poleocene                                                              Koldo
                                     SECONDARY
                                          Maestrichtion



                                                                                   in
                                                                                     5hor

                                                                                             0               50          looke


                   Figure A-1. Geology of Senegal.

                                                                          76









                                                                                             Niang

                    The Quaternary volcanism (2 MA to 500,000 ago) is represented in the
                    extreme west of the Cap Vert peninsula by the Mamelles volcano,
                    secondary eruptive bodies (Mermoz), and also by about five or six lava
                    beds and interstratified tuffs (Dia, 1980, 1982; Lo, 1988).

           Hydrodynamics

                The tidal range is only about one meter on the ocean coast, and less in most
           estuaries. The NW swells are dominant and associated with SW swells only during
           the rainy season (Figure A-2). On the North Coast, the NW swell determines a NE-
           SW littoral drift (Pinson-Mouillot, 1980).        Then, the NW swell is diffracted
           three times around the Cap Vert peninsula (Riffault, 1980), determining a
           divergence in the Hann bay and an E-W current between Rufisque and Hann (Masse,
           1968). From Rufisque, the swell obliquity increases, generating a NW-SE littoral
           drift with speeds between 0.8 m/s at Bargny and I m/s at the Somone estuary
           (Demoulin, 1967).

                Estimates of volume of sand transport by             the littoral drift vary
           (PNUE/UNESCO/ONU-DAESI, 1985), but all indicate that      the sand transport is much
           more important along the North Coast than along the      South Coast.


           THE MAIN TYPES OF COASTLINE

                Three main types of coastlines are encountered in Senegal (see Figure 1)
           (Sal I , 1982): rocky coasts (about 70 km 1 ong) , sandy coasts (about 400 km 1 ong) ,
           and the mangrove estuaries (about 250 km).

           The Rocky Coasts

                About 70 km long, they are located along the Dakar and Ndiass horsts. The
           cliffs consist of the following:

                0   Volcanic rocks along the Cap Vert peninsula.         The Tertiary eruptive
                    system of Dakar gives rise to the ankaratrite cliffs of Goree (40 m
                    high) and Cap Manuel (35-40 m) and to the basanite cliffs of Madeleines
                    Island and Fann. The Quaternary eruptive system of Mamelles gives rise
                    to the dolerite cliffs located between Yoff and Fann (10 to 12 m high);

                6   Paleocene and Eocene marly limestones for the cliffs of Popenguine, Cap
                    des Biches (13 m high),"anse" Bernard and Madeleines;

                a   Haastrichtian sandstones and shales for the cliffs of the Wass horst:
                    Cap Rouge (47 m), Toubab Diallao (12m), and Cap de Naze (about 60 m);

                0   "Continental terminal" sandstones capped by lateritic crust in
                    Casamance.

                These cliffs can be plunging cliffs (Cap Manuel) when they are made of
           volcanic rocks, or have a straight to convex face when they consist of

                                                     77










                     West Africa
                                                                                                                                      Podor


                                                                                                   S E N E G A L










                                                                       St Louis

                                                      Nov.
                                                      to
                                                      May
                                                      F                               L ougo

                                                                 200000
                                                      June     WOOL 000
                                                      to        M3/yeor                                                         LingUere
                                                      Oct.
                                                                              Neb*mer





                                         Coyar
                                         Canyon            Coyar
                                         CAP                       Thies
                                         VERT
                                                         fisque
                                             %DAKAR                                        Diourbel


                                                      25 M3
                                                           ur



                                                             M3       Joal
                                                                             0\0            Koolock             Koffrine



                                                      June
                                                      to
                                                      Oc t.                                                             .......



                                                                                 ...... ..............
                                                      Dec.                      ANJUL            G A M 8 1 E
                                                      to
                                                      Apr.




                                                                       j ........

                                                          Jul,.
                                                           to
                                                          S opt.
                                                                                                                              Wolda

                                         4            Littoral drift
                                                      Current
                                                      Swell                           cosomonc
                                                      Canyon                             Ziguinchor
                                                      Erosion

                                                      sedimentation                                     0             50               lOOkm


                     Figure A-2. Hydrodynamics                  of   Senegal.

                                                                                  78









                                                                                        Niang

           sedimentary rocks (Cap de Naze) (Sall, 1982). Generally, their base is covered
           by blocks, cobbles, and pebbles protecting them from wave attack. The abrasion
           platforms are very rare (Cap des Biches, Cap Manuel, Fann-Almadies) . Between two
           rocky capes, there are often small bay beaches.

           The Sandy Coasts

                The North Coast or "Grande Cote" (Saint-Louis to Yoff)

                Here, the straight sandy beaches are linked with three Quaternary dune
           systems present above the Eocene shaley limestones (see Figure I and Figure A-1).
           From the land to the sea, we can distinguish:

                0   The continental dunes or Ogolian red dunes (20,000-12,000 years ago)
                    with first NE-SW flattened longitudinal dunes (about 10 m high) built
                    during the arid Ogolian (18,000 years ago), followed by NNW-SSE to WNW-
                    ESE dunes of about 20 m high that are the result of Ogolian dunes
                    reworking during a short arid phase (8,000 to 6,800 years ago) (Michel,
                    1969);

                8   The semi-fixated yellow dunes built during an arid phase (Tafolian,
                    4,000-1,800 years ago) form a 250- to 4,500-m-broad dune field. They are
                    made of NNW-SSE parabolic dunes, barkhans (Pinson-Mouillot, 1980). Often
                    very high (up to 20-30 m), they are ended by an abrupt upthrow front
                    (30-450 steep, more than 30 m high) above the niayes or the red dunes
                    (Pezeril et al., 1986);

                0   The littoral dunes or white dunes form a band from a few meters to
                    hundred meters broad. They are parallel to the coast, the typical form
                    being the NNW parabolic dunes. The heights vary between a few meters
                    to 25 m maximum. They began to form during the Subactual and are still
                    supplied by the beach sands.

                The main characteristic of this littoral zone are the interdunes' so-called
           niayes, temporarily inundated by precipitation and groundwater. Three to ten
           meters above sea level, these niayes are of three different types (Michel, 1969;
           Pezeril et al., 1986); they can originate from old hydrographic networks or be
           true interdunes. These niayes are characterized by a relictual subguinean
           vegetation with the oil palmtree (Elaeis quineensis) bordering them (Fall, 1986;
           Lezine, 1986).

                The beaches are relatively narrow (between 40 m at Yoff and 110 m at
           Camberere). The average slopes are less than 8*.     The characteristic forms of
           these beaches are beach cusps, with ridges and runnels (Diaw, 1981; Sall, 1982).
           Sall (1982) proposed a model of the beach cycle, swell controlled with erosion
           during the dry season and accumulation during the wet season and determining a
           seasonal balance between the foreshore and the shore face.





                                                   79










              West Africa

                   The South Coast or "Petite Cote" (Hann to D.Jiffere)

                   Unlike the North Coast, the South Coast littoral zone is characterized by
              rocky capes and the absence of dunes (Demoulin, 1967). The beaches are lined
              with a sandy barrier, however (see Figure 1 and Figure A-1).

                   The sandy barrier can lean on a shallow lagoon or wadi or on a rocky
              bedrock. Arid during the dry season, these lagoons and wadi are filled up during
              the rainy season, sometimes inducing a barrier break with little detrital input
              to the coast (Masse, 1968).

                   Very often, we can observe behind the lagoon the Anadara senilis
              Nouakchottian terrace.   This terrace, located between +2.5 and +3 m, is the
              result of the last important Holocene transgression, the so-called Nouakchottian
              (max; at 5,500 years ago). This terrace is present at Mbao, Bargny (Demoulin,
              1967), between Mbour and Nianing (Elouard et al., 1967), and at Mbodiene (Elouard
              et al., 1967; Debenay and Bellion, 1983).

                   The sandy barrier(s), 100 to 150 m wide and less than 5 m high, can present
              several aspects (Demoulin, 1967). The fixated barrier (the most common type) is
              covered by Opuntia tuna and limited seawards by a microcliff.       In the Mbour
              sector (Elouard et al., 1977), there is a barrier of several generations, with
              the first one very rich in heavy minerals (ilmenite, zircon, and rutile). After
              this barrier, there are successive and more recent barriers up to the beach.

                   The beaches are narrow (30 to 40 m) with average slopes of 3 to 4*
              (Demoulin, 1967), the shore face being more steep (5 to 150). The beach cusps
              are well developed on this coast (Demoulin, 1967) and sometimes consist of
              pebbles. The beach sands on this coast are very often titaniferous (amorphous
              ilmenite), the more important concentrations being found at Rufisque (33,360 to
              92,580 ppm) and Tine Dine island near Joal (131,000 ppm) (Dumon, 1981).

                   One feature of this coast is the presence of Holocene to Pleistocene "beach
              rocks" (Demoulin and Masse, 1969) outcropping on the beaches at Rufisque, Bargny-
              Sienndou, and along the "Pointe de Sangomar" sand spit.     The first carbon-14
              dating made on shells have given an age of 32,500 +2150 years ago (Demoulin and
              Masse, 1969), which corresponds to the so-called Inchirian. New petrographical
              and geochemical studies (Giresse et al., 1988; Diouf, 1989) have questioned the
              previous dating.

              Mangrove Estuaries

                   Representing about 150 km of coastline, these estuaries correspond to the
              three most important rivers, from North to South:         Senegal, Saloum, and
              Casamance.

                   General Characteristics

                   In all the estuaries, the common geomorphological units have been formed
              during the last Quaternary (Sall, 1982; Diop, 1986).

                                                     80









                                                                                         Niang

                    Tidal channels. They are sinuous except in the Senegal estuary.      These
                    channels present a well-developed hierarchy. The depths are not very
                    important except in the main channels: 8-10 m in the Senegal, 6 m in
                    the Saloum, and 8-9 m in the Casamance. These channels present sandy
                    or clay channel bars, very developed and unstable in the mouth channels.
                    From north to south, the channel sediment granulometry diminishes.

                    Tidal flats-mangrove marshes-"tannes." From the tidal channel, we can
                    observe in the intertidal zone, first tidal flats then mangrove marshes
                    with Rhizophora racemosa (5 to 12 m high) replaced by R. harisonnii and
                    R. mangle in the Saloum estuary, then Avicennia africana (1 to 3 m
                    @igh).   The sediments are finer in the inner estuary than on its
                    maritime part.   From south to north, due to climatic conditions, we
                    notice a reduction of the mangrove population density and a diminution
                    of the species number (six in Casamance, four in Saloum, and two in
                    Senegal). The bare tanne presents salt efflorescences and is limited
                    by the very high tide level. The herbaceous tanne is developed beyond
                    the tide levels but can be inundated by freshwater. It is colonized by
                    an halophyte vegetation.

                6   Sandy barriers:    with "kjokkenmoddinger" and some "lunettes," they
                    constitute the rare permanent emerged units (+2 to +4 m high) in these
                    estuaries.   They are, therefore, favored sites for habitat and fresh
                    groundwater. Well developed in the Senegal estuary, they surround small
                    lagoonal lows. They are also present along the.maritime parts of the
                    Saloum and Casamance estuaries but less developed. The different sand
                    spits bordering the main rivers belong to this unit: "Langue de
                    Barbarie," "Pointe de Sangomar," and "Presqu'ile aux Oiseaux." These
                    sand spits, built since 3,000 years ago, are N-S oriented due to the
                    littoral drift.

                6   "Kjokkenmoddinger" (manmade shell deposits):      These are due to the
                    completion and trade of Anadara senilis and the Rhizophora oysters
                    (Gryphea gasar) since the Neolithic. They are accumulations sometimes
                    of huge size marked by the presence of Adansonia digitata.      They are
                    present in the three estuaries but are particularly developed in the
                    Saloum (Diop, 1986).

                The Senegal Estuary

                The estuary is a triangle. First flowing E-W with numerous meanderings, the
           Senegal River changes direction from Keur Macene, flowing NE-SW then N-S from St-
           Louis, bordered by the 25-km-long "Langue de Barbarie" sand spit.           Before
           reaching St-Louis, it receives a number of tributaries (Gorom, Lampsar), which
           are ancient deltaic channels.    From Bogue, the Senegal river bed is situated
           below the sea level (-5 m up to St-Louis).

                The Senegal estuary presents normal fluctuations with two seasons (Sall,
           1982):


                                                   81










            West Africa

                  0  A high-water season (July to November) during which there is a
                     fluviatile regime. The flood is characterized by an high interannual
                     variability in relation to the precipitation irregularity. For example,
                     at Dagana, the annual module varies between 890 m'/s during wet years
                     and 490 m/s during dry years. Studies by Kane (1985) and Gac and Kane
                     (1986) on suspended matter in the "delta" zone showed that the values
                     are higher than 200 mg/L until the beginning of the flood, then reach
                     maximum values of 686.4 mg/L (1981) and 415.8 mg/L (1982).            From
                     November, these values diminish to reach mean concentrations of 10 mg/L
                     during the low water period.     The inundated areas fluctuate between
                     100,000 and 500,000 hectares, depending on the flood quality.

                  0  A low-water season (December to June) during which the saltwater enters
                     the low estuary. The mechanism of the salt intrusion has been described
                     by Gac et al. (1986a,b). The salt front was found around Richard Toll
                     (170 km from the mouth) during wet periods and reached Dagana (217 km
                     from the mouth) during dry periods.

                  The Saloum Estuary

                  It opens into the Atlantic Ocean through three distributaries: the Saloum,
            the Diomboss, and the Bandiala separating three groups of islands (Gandoul to the
            North, Betanti and Fathila to the South). The three distributaries are connected
            by a dense network of small and shallow tidal channels, the so-called bolons.
            The Saloum is bordered by a 20-km-long sand spit, the "Pointe de Sangomar." A
            mangrove swamp stretches all over the estuary. The main characteristics of the
            Saloum estuary are the following:

                  0  Hydrodynamic and hydrological regime: several studies conducted between
                     1981 and 1984 (EPEEC, 1983, 1984; UNESCO, 1985) have proposed for the
                     Saloum and Diomboss a reverse estuarine model (Barusseau et al., 1985,
                     1986) due to the weak or absent freshwater inflow (water discharges
                     lower than 0.7 m/s (Diop, 1986)).       The characterized model of the
                     regime is as follows: the flood phase lasts longer than the ebb, with
                     current velocities generally higher during the flood than on the ebb;
                     and the Saloum distributaries receive more water than flows back into
                     the sea (about 66%); the estuarine salinity is always higher than the
                     seawater, even after the wet season. It increases from the mouth (35%
                     in the wet season, 55% in the dry season) to the upstream end of the
                     estuary (respectively, 42 and 88% in Kaolack).

                  0  The Saloum estuary is characterized by the presence of relatively coarse
                     sediments, and, even if the fine fraction is important, it is silt
                     dominated.    The percentage of carbonates is low (<5%) due to the
                     mechanical  and chemical destruction (low pH) of the shells.

                  0  Studies on the mangrove population along the Saloum (UNESCO, 1985) have
                     shown that from the mouth to the upstream part of the estuary, there has
                     been a height reduction of Rhizophora, diminution of the area occupied
                     by Rhizophora, of the population density and augmentation of dead

                                                    82









                                                                                            Niang

                    Rhizophora. Finally, the mangrove disappears upstream of Foundiougne.
                    This regression of the mangrove environment will be related to the
                    drought, to the human activities (use of trees for cooking, small-scale
                    exploitation of salt), and to natural diseases.

                    The great development of "kjokkenmoddinger."

               The  Casamance Estuary

                It  is, in fact, a ria dominated by the "Continental terminal" sandstone
          plateau   (30-40 m high) often capped by a lateritic crust (Pages et al., 1987).
          During the last 240 km, the slope of the Casamance is null.             Downstream of
          Ziguinchor, the Casamance River receives the Diouloulou tributary and there are
          numerous small tidal channels interconnected ("bolons"). The mangrove marshes
          are well developed with Rhizophora racemosa and Avicennia nitida, followed by the
          tannes.   There are two types of sandy barriers (TECASEN, 1979). The recent ones,
          like the "Presqulile aux Oiseaux" which is a sand spit, are N-S oriented in the
          direction of the actual littoral drift; the old ones (since about 4,000 years
          ago) are oriented NNW-SSE (change of direction of the littoral drift since 4,000
          years ago) or NE-SW south of the Casamance mouth (built by the SW swells).

               The water discharges are relatively low.         During wet years (1962, 1967,
          1969, 1975), the annual module was of 6.4 m/s with a maximum of 32 m3/s.             But
          now, with the drought, the annual module is of 1.7 m3/s with a maximum of 6.8
          m3/S  (Pages et al., 1987).       Before 1970, the Casamance River had a normal
          estuarine function, but now it is a reverse estuary like the Saloum (Debenay et
          al., 1987; Pages et al., 1987). Actually, the salinity increases upstream with
          values higher than 100% upstream of Sedhiou located 200 km from the mouth (max;
          of 170% in June 1986) (Pages and Debenay, 1987).


          BIBLIOGRAPHY

          Barbey, C., and Chamard, P. 1970. Contribution a lletude petrographique des
          sables de la presqulile du Cap Vert. Bull. IFAN, Dakar, (A), 32-3:569-584.

          Barusseau, J.P., Diop, E.H.S., and Saos, J.L.           1985.   Evidence of dynamics
          reversal    in   tropical    estuaries,    geomorphological    and    sedimentological
          consequences (Salum and Casamance Rivers, Senegal). Sedimentol. 32(4):543-552.

          Barusseau, J.P., Diop, E.H.S., Giresse, P., Monteillet, J., and Saos, J.L. 1986.
          Consequences sedimentologiques de 1'evolution climatique fini-Holocene 102-103
          ans) dans le delta du Saloum (Senegal). Oceanogr. trop. 21(l):89-98.

          Bellion, Y.J.C. 1987. Histoire geodynamique post-paleozoique de l'Afrique de
          l'Ouest d'apres 1'etude de quelques bassins sedimentaires (Senegal, Taoudenni
          Iullemme-den, Tchad). Thesis, Avignon, 302 p.

          Biarnes, P. 1988. Senegal-1988. Marches Tropicaux. Mediterraneens, Paris, 13
          P.

                                                     83










                Nest Africa

                Boivin, P., Loyer, J.Y., Mougenot, B., and Zante, P.           1986.    Secheresse et
                evolution des sediments fluviomarins au Senegal.           In:    Symp INQUA/ASEQUA,
                Changements globaux en Afrique durant le Quaternaire:            Passe-Present-Futur.
                Paris: Orstom, p. 43-48.

                B.R.G.M.   1962.   Carte geologique du Senegal (echelle 1/500 000, 4 feuilles).
                Serv. Mines et Geol., Dakar, 36 p.

                B.R.G.M. and D.M.G. ed. 1985. Plan mineral de la Republique du Senegal. Min.
                Dev. Ind. Artisanat, Dakar, 3 volumes, 725 p.


                Bruun, P. 1962. Sea level rise as a cause of shoreline erosion. Am. Soc. Civil
                Eng., Proc. V.88 Waterways and Harbours Division Journal WW1:117-130.

                Debenay, J.P., and Bellion, Y. 1983. Le quaternaire recent des microfalaises
                de Mbodiene (Senegal): stratigraphie, variations du niveau marin. Ass. senegal.
                Et. Quatern. Afr. Bull. liaison, Dakar, p. 70-71, 73-81.

                Debenay, J.P., Ba, M., Ly, A., and Sy, 1. 1987. Les ecosystemes paraliques du
                Senegal. Description, repartition des peuplements de Foraminiferes benthiques.
                Rev. Paleobiol. 6(2):229-255.

                Demoulin, D.    1967.   Etude de la morphologie littorale de la Petite Cote de
                Bargny au marigot de la Nougouna (Senegal). La cote basse de Bargny Guedj a Yene
                Tode. Dipl. Et. Sup., Dakar, 122 p.

                Demoulin, D., and Masse, J.P. 1969. Gres de plage de la presqu'ile du Cap Vert
                (Senegal). Bull. IFAN, Dakar, (A), 31(3):721-738.

                D.H.V. Ingenieurs Consefls. 1979. Rapport sur 1 'etude de la protection du rivage
                de la Petite Cote. Min. Equip. Dakar, 92 p.

                Dia, A. 1980. Contribution a l 'etude des materiaux volcaniques de la presqu'ile
                du Cap Vert et du plateau de Thies. Inventaire et etude preliminaire des sites.
                Rapt Dpt. Geol., Dakar, Nlle Ser., 6, 92 p.

                Dia, A.   1982.   Contribution a 1'etude des caracteristiques petrographiques,
                petrochimi-ques et geotechniques des granulats basaltiques de la presqu'ile du
                Cap Vert et du plateau de Thies (carriere de Diack-Senegal). Thesis, Dakar, 183
                P.

                Diaw, A.T. 1981. Etude morpho-sedimentologique de 1'estran sur la cote nord du
                Senegal. Bull. IFAN, Dakar, (A), 43:1-2, 69-78.

                Diop, E.H.S. 1986. Estuaires holocenes tropicaux. Etude de geographie physique
                comparee des "Rivieres du Sud": du Saloum (Senegal) a la Mellacoree (Republique
                de Guinee). Thesis, Strasbourg, 2 volumes, 522 p.



                                                         84









                                                                                               Niang

           Diop, E.S., and Sall, M. 1986. Estuaires et mangroves en Afrique de l'Ouest:
           evolution et changements du Quaternaire recent a l'Actuel.                    In Symp.
           INQUA/ASEQUA, Changements globaux en Afrique durant le Quaternaire: Passe-
           Present-Futur. Paris: Orstom, p. 109-114.

           Diouf, M.B. 1989. Sedimentologie, mineralogie et geochimie des gres carbonates
           quaternaires du littoral senegalo-mauritanien. Thesis, Perpignan, 237 p.

           Dumon, J.C. 1981. Comportement du titane dans les phenomenes d'alteration et
           de sedimentation sous differents climats: Esquisse d1un cycle biogeochimique.
           Thesis, Bordeaux I, No. 718, 296 p.

           Elouard, P. 1980. Geomorphologie structurale, lithologique et climatique de la
           presqulile du Cap Vert (Senegal). Notes Afr., IFAN, Dakar, 167:1-68.

           Elouard, P., Faure, H., and Hebrard, L.          1967.   Quaternaire de la region de
           Mbour. Sixth Cong. Panafr. Prehist. Et. Quatern., Dakar, p. 31-33.

           Elouard, P., Faure, H., and Hebrard, L. 1977. Variations du niveau de la mer
           au cours des 15,000 dernieres annees autour de la presqu'ile du Cap Vert. Dakar,
           Senegal. Bull. liaison Ass. seneg. Et. Quatern. Afr., Dakar, 50:29-49.

           E. P. E. E. C. 1983. Atel i er d'etude des mangroves au Sud de 1 1 estuai re du Sal oum:
           Diomboss-Bandiala (Senegal). UNESCO/ROSTA, Dakar, 219 p.

           E. P. E. E. C. 1984. Etude des mangroves et estuai res du Senegal : Sal om et Somone.
           UNESCO/ROSTA, Dakar, 88 p.

           Fall , M.    1986.    Environnements sedimentaires quaternaires et actuels des
           tourbieres des niayes de la Grande Cote du Senegal. Thesis, Dakar, 130 p.

           Faure, H., Fontes, J.C., Hebrard, L., Monteillet, J., and Pirazzoli, P.A. 1980.
           Geoidal change and shore-level tilt along Holocene estuaries: Senegal river area,
           West Africa. Science 210:421-423.

           Gac, J.Y., Kane, A., and Monteillet, J. 1982. Migrations de 1'embouchure du
           fleuve Senegal depuis 1850. Paris: Cahiers Orstom, Ser. Geol. 12(l):73-75.

           Gac, J.Y., Carn, M., and Saos, J.L.         1986a.   L'invasion marine dans la basse
           vallee du fleuve Senegal . I.Periode 1903-1980. Rev. Hydrobiol . trop. 19(l):3-17.

           Gac, J.Y., Carn, M., and Saos, J.L. 1986b. L'invasion marine dans la basse
           vallee du fleuve Senegal. I.Periode 1980-1983: proposition d1un nouveau modele
           d'intrusion    continentale des      eaux oceaniques.         Rev.   Hydrobiol.     trop.
           19(2):93-108.

           Gac, J.Y., and Kane, A. 1986. Le Fleuve Senegal: I. Bilan hydrologique et flux
           continentaux de matieres particulaires a 1'embouchure.                  Sciences Geol.
           39(l):99-130.


                                                      85










                klest Africa

                Giresse, P., Diouf, M., and Barusseau, J.P. 1988. Lithological, mineralogical
                and geochemical observations of Senegal o-Mauri tani an Quaternary shoreline
                deposits: possible chronological revisions. Paleogeogr. Palaeocl im. Palaeoecol .
                68:241-257.

                Kane, A. 1985. Le bassin du fleuve Senegal a 1'embouchure. Flux continentaux
                dissous et particulaires. Invasion marine dans la vallee du fleuve.              Thesis,
                Nancy 1, 205 p.

                Lezine, A.-M. 1986. Environnement et paleoenvironnement des niayes depuis 12
                000 B.P. In Symp.INQUA/ASEQUA, Changements globaux en Afrique durant le
                Quaternaire: Passe-Present-Futur. Paris: Orstom, p. 261-263.

                Lo, P. G.    1988.    Le volcanisme quaternaire de Dakar (Senegal occidental)-
                particularites     petrographiques,      caracteres     geochimiques.      Implication;
                petrogenetiques. Thesis, Nancy 1, 143 p.

                Lompo, M. 1987. Methodes et etude de la fracturation et des filons. Exemple de
                la region du Cap Vert (Senegal). Mem. DEA, Dakar, 58 p.

                Marius, C., Lucas, J., and Kalck, Y. 1986. Evolution du golfe de Casamance au
                Quaternaire recent et changements de la vegetation et des sols de mangroves lies
                a la secheresse actuelle. In Symp.INQUA/ASEQUA, Changements.globaux en Afrique
                durant le Quaternaire: Passe-Present-Futur. Paris: Orstom, p. 293-295.

                Masse, J.P.    1968.    Contribution a 1'etude des sediments actuels du plateau
                continental de la region de Dakar (Republique du Senegal).           Rapp. Lab. Geol.
                23:81 p.

                Michel, P.       1969.    Les bassins des fleuves Senegal et Gambie. Etude
                geomorphologique. Thesis, Strasbourg, 1169 p.

                Michel, P., and Sall, M.      1984.   Dynamique des paysages et amenagement de la
                vallee alluviale du Senegal. Paris: Mem. Orstom, No. 106, p. 89-109.

                Murday, M. 1986. Beach erosion in West Africa. Res. Plan. Inst. ed., Columbia,
                101 P.

                01 i vry, J. C.  1.983.  Le point en 1982 sur l1evolution de la secheresse en
                Senegambie et aux iles du Cap Vert. Examen de quelques series de longue duree
                (debits et precipitations). Paris: Cahiers Orstom, Ser.Hydrol. 20(l):47-69.

                Pages, J., and Debenay, J.P. 1987. Evolution saisonniere de la salinite de la
                Casamance. Description. et essai de modelisation.             Rev. Hydrobiol. trop.
                20(3-4):203-217.

                Pages, J. , Debenay, J. P. , and Lebrusq, J. Y. 1987. Uenvi ronnement estuari en de
                la Casamance. Rev. Hydrobiol. trop. 20(3-4):191-202.



                                                          86









                                                                                             Niang

          Paradi s, G. 1986. Rol e de 1 'homme dans I es changements du paysage tropi cal : 1 es
          mangroves ouest africaines. In Symp.INQUA/ASEQUA, Changements globaux en Afrique
          durant le Quaternaire: Passe-Present-Futur. Paris: Orstom, p. 357-362.

          Pelissier, P. 1983. Atlas du Senegal. Paris: Jeune Afrique, 72 p.

          Pezeril, G., Chateauneuf, J.J., and Diop, C.E.W. 1986. La tourbe des niayes au
          Senegal: genese et gitologie.       In Symp. INQUA/ASEQUA, Changements globaux en
          Afrique durant le Quaternaire. Passe-Present-Futur. Paris: Orstom, p. 385-392.

          Pinson-Mouillot, J.       1980.     Les environnements sedimentaires actuels et
          quaternaires du plateau continental senegalais (Nord de la presqulile du Cap
          Vert). Thesis, Bordeaux 1, No. 1554, 106 p.

          PNUE/UNESCO/ONU-DAESI.      1985.   Erosion cotiere en Afrique de l'Ouest et du
          Centre. Rapp Et. Mers regionales Geneve, 67, 248 p.

          Riffault, A. 1980. Les environnements sedimentaires actuels et quaternaires du
          plateau continental senegalais (Sud de la presqu'ile du Cap Vert).              Thesis,
          Bordeaux I, No. 1561, 145 p.

          Sall, M.    1982.    Dynamique et morphogenese actuelles au Senegal Occidental.
          Thesis, Strasbourg, 604 p.

          Sy, A.     1982.     Etude geomorphologique des fleches sableuses du littoral
          senegalais: Langue de Barbarie (Nord Senegal), Pointe de Sangomar (Saloum),
          Presqu'ile aux Oiseaux (Casamance). Trav. Et. Rech., Dakar, 103 p.

          Sy-Niang I. Littoral ore deposits in Senegal. In International Conference on
          Geosciences in Development. Nottingham, England: in preparation.

          TECASEN.    1979.   Teledetection de quelques geosystemes littoraux senegalais.
          Depart. Geogr. Dakar, E.N.S.J.F. Montrouge, Rapp.1, 83 p.

          UNESCO.    1985.   L'estuaire et la mangrove du Sine Saloum. Proceedings of a
          regional UNESCO-COMAR workshop held in Dakar (Senegal) February 28 to March 5,
          1983. Rap. UNESCO Sciences de la Mer, No. 32, 139 p.













                                                    87










                             RESPONSE TO EXPECTED IMPACT OF
                          CLIMATE CHANGE ON THE LAGOONAL AND
                            MARINE SECTORS OF COTE VIVOIRE



                                       PHILIBERT KOFFI KOFFI
                                             NASSERA KABA
                                             SOKO G. ZABI
                           Oceanographic     Research Center of Abidjan
                                        Abidjan, Ivory Coast






           INTRODUCTION

                 Since 1985, scientists in the Oceanographic Research Center of Abidjan
           (Cote d'Ivoire) have been studying erosion. Although the southwest shoreline
           (Tabou-Sassandra) is stable, the southeast (Fresco-Vri d i -Port -Bouet-Ghana) border
           is very unstable and is eroding at the rate of 1 to 2 m/year. Although part of
           that erosion results from the Vridi Canal and the Bottomless Pit Canyon, the
           Fresco-Vridi area appears to be eroding as a natural consequence of current sea
           level trends.

                The potential implications of an accelerated rise for Cote d'Ivoire are
           similar to those for other nations in West Africa.        Erosion would accelerate
           threatening some structures. Perhaps more important are the implications for
           the lagoonal systems. If the outer barriers should break up due to erosion and
           inundation, these lagoons might become exposed to the open ocean; even where the
           barriers remain intact, rising water levels could drown the intertidal wetland
           areas. In either event, subsistence fishing in the lagoons would be seriously
           threatened.

                 This paper briefly describes the environmental conditions along Cote
           d'Ivoire and the administrative structure for dealing with coastal management
           issues.



           GENERAL DESCRIPTION OF LAGOON AND MARINE ENVIRONMENTS

                 Cote d'Ivoire is located in West Africa on the Gulf of Guinea (Atlantic
           Ocean), between latitudes 4* and 11* North; its surface area is 322,463 square
           kilometers. Its 500-km coastline is fringed with 350 km of lagoons, which are
           separated from the sea by a narrow offshore bar and a narrow continental shelf.

                                                    89










               West Africa

               Of the nation's 10 million people, about 3 million live along the coast (about
               2 million in and around Abidjan).

                      The climate is warm and humid in the south and tropical dry in the north,
               which results in two major types of vegetation: guinean (dense forests and pre-
               forest savannahs) and sudanese (savannahs).         The economy of Cote d'Ivoire is
               essentially based on agriculture: traditional agriculture using slash and burn
               techniques, and industrial plantations using very extended land areas.                The
               industrial growth rate for the last three decades has been about 7% from 1960
               to 1984.

               Lagoons

                      Lagoons are found along 60 percent of the coast and cover about 1200 square
               km. There are three main lagoons (Grand-Lahou, Ebrie, and Aby Lagoon) connected
               with the sea and each other by natural or artificial channels.               Grand-Lahou
               lagoon, which covers 190 square km, is the smallest and shallowest (average depth
               of 3 m). The Bandama River, which drains the largest watershed of Cote dlIvoire,
               flows into it. Ebrie Lagoon, in the middle, covers 566 square km and is on an
               average, 4.8 km deep.     It is connected to the sea by the Vridi Canal and Grand-
               Bassam Channel. Aby Lagoon, near the Ghana border, covers 424 square km.

                      Lagoonal seasons are determi ned by ri verf 1 ow and rai nf al I . The dry season
               (January to April) is characterized by marine influence (maximum temperature and
               salinity).    During the rainy season (May to August), heavy rains swell forest
               rivers.   The flood season (from September to December) corresponds to maximum
               inputs by "Sudanese" rivers (Comoe and Bandama) causing lagoon salinities to
               approach zero.

                    A change in climate-could affect these lagoons in many ways. The inundation
               of intertidal vegetation would remove important habitats for fisheries. Erosion
               and flooding would increasingly threaten establishments along the shore. Rising
               seas and decreased precipitation would increase the salinity of the lagoons,
               perhaps leading to increased predation in some cases.

               The.Open Coast

                     There are two types of landscapes in the coastal region:           (1) cliffs of
               the southwest (from the Liberian border to Fresco) are characterized by a step-
               like profile where a narrow quaternary coastline and the contact of the
               precambrian plinth alternate.       These plateau-coasts, cut as abrupt or gently
               sloping cliffs, are elevated more than 20 m above sea level (more than 65 m in
               the San Pedro sector); and (2) sandy low coasts (from Fresco to the Ghana
               border), which have flat landscapes where the quaternary shoreline is more
               developed (maximal width 4,500 m) and continuous.         Low plateaus of the nearby
               inland areas are generally less than 12 m above sea level. The land adjacent
               to the sandy shorelines is usually 2-6 meters above sea level -- even lower near
               Assinie.




                                                          90










                                                                                Koffi, et al.

                There are two major marine seasons: a major warm season (from February
         to May) during which water temperatures vary from 27 to 28*C; and a major cold
         season (from July to October) during which the upwelling is more distinct, water
         temperatures are less than 230C, and the salinity is near 35%. Beside these two
         distinct seasons, there is a short warm season (November to December) with the
         disappearance of the upwelling, and a short cold season (December to January)
         with a coastal upwelling and water temperature varying from 24 to 250C.

               If sea level rises one meter, the Bruun rule implies that sandy beaches
         could erode 100-200 meters, which would threaten some establishments along the
         coast. In addition, upwelling and other aspects of the marine climate have an
         important impact on fisheries.        If climate change alters the seasonal or
         geographical extent of upwelling, fishing would probably be affected.


         PROTECTION OF THE ENVIRONMENT IN COTE DIIVOIRE

         Administrative and Institutional Efforts

                Environmental protection is a national concern. Among the institutional
         establishments dealing with this subject are the Oceanographic Research Center,
         the Tropical Ecology Institute, the National Agency of Meteorology, the National
         Committee for fighting bush fires, and nongovernmental organizations like the
         Green Cross.    Cote d'Ivoire has also signed several international conventions
         in environmental protection.     Actions against environmental degradation include
         the monitoring of coastal erosion.    ;
                Shoreline evolution and coastal erosion have been studied since 1985 at
         18 stations from Tabou to Assinie. The initial results are as follows: (1) the
         southwest shore (Tabou-Sassandra) is stable because of its geology and steplike
         formation; and (2) the sandy low coast at the southeast (Fresco-Vri di - Port- Bouet-
         Ghana border) is very unstable and is eroding at 1 to 2 m/year. This area in
         turn can be divided into an area with natural erosion (Fresco-Vridi) and an area
         where erosion is linked both to the presence of the Vridi canal and the proximity
         of the "Bottomless Pit" canyon (Vridi-Port-Bouet).

                The aim of this erosion study is to establish a coastline sensitivity map.
         This map will include the geology and coastal shapes, erosion and sedimentation
         rate of the coastline, coastal drift, the topography of the coast, and inter-
         tidal zones. This study will help in managing (1) passive measures of coastal
         protection; (2) the exploitation of quarries (sand and others); and (3) refining
         a sedimentation model built to predict erosion and the effectiveness of
         protection options for the Abidjan area.

              With respect to the fight against deforestation, Cote d'Ivoire has
         established a permanent national forest domain in the thick forest and savannah
         zones (decree no. 78-231 of 3/15/78), which includes a total of 5,921,558
         hectares divided into 205 forests and parks. A program of reforestation favoring
         rapid-growing species of trees is being instituted, which will help slow global
         warming by providing a natural sink for carbon dioxide.

                                                   91











              West Africa

              Major Constraints to Environmental Protection

                    An obstacle to protecting and managing the environment is the antagonism
              between environmental and developmental forces, which must be reduced to achieve
              the benefit of an effective equilibrium between the two.

                    The search for this precarious equilibrium is sometimes difficult because
              of the ingrained habits of people, which are often detrimental to the
              environment, and because of financial constraints.


              CONCLUSION

                    The Ministry of Defense and the Ministry of Scientific Research coordinate
              national activities related to research and monitoring of meteorological and
              oceanographic   surface   conditions   among  all   regional   institutions    with
              responsibilities for studying climatic variability and its local impact. We need
              to establish public education projects to promote an understanding of changing
              climate and rising seas, to assess its potential impacts on society, and to
              encourage regional scientific centers related to environmental research to
              establish studies to identify the vulnerability of particular geographical areas.




























                                                      92











                       IMPLICATIONS OF GLOBAL WARMING AND
                               SEA LEVEL RISE FOR GHANA


                                           J. F. ABBAN
                                      Hydrology Division
                      Architecture and Engineering Services Corp.
                                          Accra, Ghana






         ABSTRACT

              This paper identifies coastal areas in Ghana subject to erosion and some of
         the causes of erosion, such as artificial structures along the coast or river
         barriers.   The socioeconomic aspects of sea erosion are also highlighted,
         including the displacement of people with subsequent destruction of economic
         activities, and the threat to tourist activities. Some of the studies conducted
         to evaluate shoreline recession are discussed, as are attempts that have been
         made to arrest or to contain sea erosion.     Finally, this paper addresses sea
         level rise and ways to assess it with data that could be obtained in Ghana.


         INTRODUCTION

              The Ghanaian coastline stretches roughly 550 km from Half Assini in the west
         to Aflao in the east. A substantial number of dwellings, commercial activities,
         and industries, as well as fishing and tourism, are found within 300 m of the
         ocean coast. Coastal areas can be grouped into three basic economic categories:

              1.  Commercial and industrial areas, such as Accra, Tema, Sekondi, and
                  Takoradi;

              2.  Fishing areas, such as Tema, Keta, and Winneba; and

              3.  Tourist areas, such as Batianor, Ada, Labadi, Biniwa, Elmina, Winneba,
                  and Busia.

              Coastal erosion is experienced in varying degrees; the adverse effects on
         developments along the coastal zones cannot be overemphasized.      The immediate
         result of shoreline retreat is the loss of land, which in almost all cases
         results in loss of properties and displacement of people. , Erosion greatly
         affects the social and economic activities of coastal dwellers and users. Lack
         of economic activities means lack of jobs or forced change of vocation, with a

                                                 93










               West Africa

               subsequent loss of revenue to the government. New fishing areas must be sought,
               and tourist sites are threatened. A typical example is Keta, where portions of
               thetpopulation had to seek shelter elsewhere because properties had been engulfed
               by the sea. The Labadi pleasure beach, until coastal protection measures were
               carried out, lost its tourist business to other areas.          Bortianor, another
               tourist spot, is being seriously threatened by coastal erosion.


               COASTAL ZONE

                    Most of the coastal areas in Ghana are low-lying and sandy, interspersed
               with beach rocks and rock outcrops.      In some areas experiencing active beach
               erosion (see Figures I and 2, which show shoreline changes for Keta and Ada,
               respectively), shoreline changes have been monitored; these areas include Axim,
               Dixcove, Nkontompo, Labadi, Ada, and Keta.       Records for periods indicated in
               Table I have been kept for Keta, Ada, Labadi, and Nkontompo.


                                   Table 1. Periods of Shoreline Monitoring


                      Town                     Period                    Remarks


                    Keta                       1907-87             Soil logging
                                               1971-87             Beach profile monitoring
                    Ada                               1941-85            Soil logging
                                               1980-86             Beach profile monitoring
                    Labadi                     1954-65             Soil logging
                                               1968-71             Beach profile monitoring
                    Nkontompo                  1956-86             Geological data
                      (Sekondi)                1971-86             Beach profile monitoring



                    Studies conducted on these areas indicate      the following major causes of
               erosion:

                    1.  Creation of artificial barriers across some rivers (e.g., the Volta and
                        Densu), which reduce or otherwise interfere with the sediment load to
                        the coast;

                    2.  Creation of artificial harbors (e.g., the Takoradi and Tema Ports),
                        where breakwaters and jetties interrupt littoral transport of sand and
                        other sediments;

                    3.  The mining of sand along the coastline, which removes supply material
                        from the coastal zone so that natural shoreline stability is diminished;
                        and



                                                        94










                                                                                                                                                                                                                          Abban







                                                                                                                                                                                                                               iA-















                                                                                                                                                                                       ...... . . . . .


                                                                 ATLANTIC OCEAN





                          Figure 1. Successive flooding and erosion through the years at Keta.








                                                                                                                                                                                         JU       1987


                                                                                                                                                                                                -1947


                                                                                                                                                                                               19"q                      `7
                                                                                                                                             j                                       W.A 11f
                                                                                                                                                                                          C 1949



                                           N


                                                                                                    OP
                                                                                                                                                                                       1907



                          Figure 2. Successive flooding and erosion through the years at Ada.

                                                                                                                                95











               West Africa

                    4.   Natural, constant coastal processes (e.g., subsidence, seasonal and
                         interannual wave climate variability, and'tectonic movement).


               WETLANDS

                    The Ghanaian wetland ecosystem has not been exhaustively studied in the
               environmental context, but a few studies have been conducted through the graduate
               school at the University of Cape Coast. The Environmental Protection Agency of
               Ghana is generally responsible for the policies developed to protect the wetland
               ecosystems.

                    Two types of marsh-ecosystems are found in the West African region:

                    1.   Wet-humid areas dominated by grasses and marshy shrubs (found near small
                         estuaries and lagoons); and

                    2.   Mangrove-type vegetation dominated by.almo@t all types of hydrophilic
                         angiosperms (with monocots of oil palm in plantations near large
                         estuaries).

                    Human habitation is common in the areas described above, since these
               ecosystems are also dominated by fauna that form the economic basis of the
               region.    Fishing is the predominant activity in Ghana and the west coast of
               Africa.    Most of the wetlands on the Ghanaian' coast are natural, and human
               habitation and industry have not yet taken their toll. Mangroves generally are
               not cut, except i n cases where 1 and has to be cl eared f or f armi ng purposes, e. g. ,
               rice farming. This is all the more reason why specific policies and research
               leading to protection of such areas should be initiated now.


               SALTWATER INTRUSION

                    Coastal river estuaries are subjected to saltwater intrusion. Low riverflow
               allows seawater to intrude farther upstream. This tends to. seriously affect the
               drinking water supply in areas such as Ada and Keta, where the local residents
               rely on groundwater as a source of drinking water.            In some cases, the high
               salinity of the groundwater has made the water unsuitable for drinking.


               FLOODING

                    Flooding along the coastal areas occurs in Accra, Botianor, and Keta.
               Floods in Accra are mainly due to improper     planning or to the inadequate drainage
               system.   Efforts to desilt and improve        the hydraulics of the primary drains
               (stormwater    channels),    coupled with      various   maintenance     schemes,    have
               significantly reduced flooding in Accra.

                    Flooding in Botianor is due mainly to     releases from the Weija Reservoir (one
               of the impounding waters proyiding Accra       with a water supply) during the rainy

                                                          96











                                                                                        Abban

          seasons. This could be controlled by proper regulation of the Weija Reservoir,
          channeling the river downstream from the dam, and construction of a proper
          outfall to the sea.

               Since the early 1960's, three floods in Keta have been caused by excess
          water discharged into the Keta Lagoon from the Todzie and Belikpa Rivers during
          exceptionally wet seasons. The creeks connecting the Keta Lagoon to the River
          Volta estuary are blocked and, therefore, the excess water is impounded in the
          lagoon instead of being discharged into the sea.


          POPULATION

               About 13.5 million people were estimated to live in Ghana in 1987, with a
          large percentage residing in the coastal zone where most of the major cities are
          located. Population density in the coastal urban areas exceeds 550 people per
          square kilometer, 10 times the density of inland areas.           The I ast three
          population censuses indicate that the Keta area (including Kedzi and Vodza) is
          being rapidly depopulated, the result of severe erosion coupled with non-
          availability of land.


          COMMERCIAL ACTIVITY

               Ghanaian coastal area inhabitants are primarily fishermen, except for those
          directly in commercial centers such as Labadi, a suburb of Accra (the capital of
          Ghana), Tema, and Sekondi.     Although Keta used to be a bustling commercial
          center, these activities have dwindled to nothing because of severe waterfront
          erosion.



          TOURISM

               Some of the tourist beaches along the Ghanaian coastal zone are Ada,
          Chemuna, Labadi, Botianor, Biriwa, Elmina, Winneba, and Busia.         Erosion of
          varying degrees has been recorded in these areas.


          AGRICULTURE AND FISHING

               The most important crop in Ghana is cocoa, which accounts for about 60
          percent of the nation's exports. Although the cocoa-growing area is not located
          in the coastal zone, shipments must pass through the coastal ports. Production
          of corn and other grains is substantial and is increasing.         Data for 1969
          indicate that production of corn and rice totaled 305,000 and 61,000 metric tons,
          respectively; fishing produced 162,800 metric tons.      In 1969, salt production
          totaled 1,700 metric tons in the coastal lagoon area.

               Although fishing is the mainstay of the coastal people, some inhabitants
          move inland to practice arable farming during the off-season. Some of the local

                                                  97











              West Africa

              farms along the fringes of the Keta Lagoon primarily cultivate shallots, rice,
              sugarcane, okra, pepper, and maize. These farming activities are disrupted each
              time the Keta Lagoon is flooded.


              COASTAL LAND DEVELOPMENT RESTRICTIONS

                  No consistent rules seem to limit coastal land development. In the past,
              coconut trees planted along the coast indicated the off-limit zones for building
              structures. However, the zones vary from place to place; in some beach areas,
              structures are very close to the coastline.

                  In areas of active sea erosion, such as Keta, Vodza, Kedzi, and Labadi, the
              coconut plantations have been claimed by the sea; thus, development, previously
              behind the plantations are now close to the sea.


              STRUCTURES ALONG THE COAST OR COASTAL WATERS

                  Four major ports are located along the shores of Ghana:       Tema, Elmina,
              Sekondi, and Takoradi.   Sekondi is a naval port, and Tema and Takoradi are
              commercial ports.  Tema has a fishing port attached, and Elmina is purely for
              fishing. All four harbors are manmade, and their breakwaters protrude into the
              sea. Elmina harbor has two basins: the inner basin is in the Benya Lagoon, and
              the outer basin is at the mouth of the lagoon where the lagoon water discharges
              into the sea.

                  Apart from Tema harbor, where erosion is occurring on the western side of
              the breakwater structure, erosion is occurring on the leeward (eastern) side of
              the harbors.

                  Takoradi and Tema have tidal gauges.    The Takoradi and Tema harbors were
              opened in 1928 and 1962, respectively. The tidal gauge installations are as old
              as the ports. Hydrological gauging stations are also located in the Keta Lagoon
              and on the Volta estuary at Ada. Hydrological gauges were established at Keta
              and Ada in August 1963 and September 1963, respectively. The mean range of the
              semidiurnal tide along the Ghanaian coast is a nearly uniform 1.0 meters.


              EFFECTS OF A ONE-METER SEA LEVEL RISE

                  A one-meter sea level rise would have a serious negative socioeconomic
              impact on the country, causing storm flooding, beach and coastal erosion, and
              loss of wetlands.

              Storm Flooding

                  A one-meter rise in sea level would create a higher mean water level in
              coastal lagoons and estuaries. This, combined with high riverflow due to heavy
              rainfall, would exacerbate the flooding that presently occurs.    Such flooding

                                                    98











                                                                                         Abban

          would cause additional loss of property and would very likely require relocating
          whole communities and industries.

               As indicated previously, Accra and Keta are but two examples of areas of
          constant flooding.    Although Accra and Botianor floods are attributed to an
          inadequate drainage system and improper regulation of Weija Reservoir,
          respectively, these areas, like many coastal towns, have drainage outlets subject
          to tidal influence of the sea. Flooding affects industries through inundation
          of warehouses, which results in damage to equipment, raw materials, and
          manufactured goods. Some residential areas near natural drainage channels are
          constantly flooded during the wet season.

               The traditional reaction of local people is to move out until the floods
          subside and then to move back again.         Some people, however, tend to find
          permanent accommodations elsewhere.

               The government antiflooding program, especially in Accra and other coastal
          areas, focuses on improving the drainage system in these areas. The government
          is also discouraging development of lowland areas.

               The projected sea level rise would allow water pushed by coastal storms to
          surge farther ashore with devastating effects.

          Beach and Coastal Erosion

               The projected one-meter rise in sea level would exacerbate the erosion
          already seen along the low-lying sandy coast of Ghana.       Loss of these coastal
          lands would have a far-reaching socioeconomic impact on the nation.          Coastal
          tourist enterprises would be at risk; commercial and industrial sites would need
          major protection or relocation. Agriculture in the near-shore zone might suffer,
          requiring inhabitants either to move or to change crops to remain productive.

          Loss of Wetlands

               The rate of natural growth and migration might not be able to keep pace with
          the rate of wetland submersion caused by rapid sea level rise. Consequently,
          valuable wetlands could be lost. A more gradual rise might permit wetlands to
          survive and migrate.     Wetland migration could occur only in areas having no
          barriers to lateral displacement.       Agricultural lands, sharply rising land
          contours, dams, or other barriers would interfere with migration.


          IMPACT ON FUTURE DECISIONS

               Sea level rise would certainly influence the development of new settlements
          and the use of beaches as recreational grounds. Existing laws would have to be
          enforced or modified, especially regarding restrictions on development of the
          coastal zone.    Decisions would have to be made concerning whether or not to
          resettle people affected by sea level rise.


                                                   99











              Uest Africa

              Response to Sea Level Rise

                   The country will have to reassess its planning with regard to development
              along the coastal area once the sea level rise impacts have been identified and
              quantified.

                   Historical records of the tidal and hydrological stations mentioned
              previously, together with studies conducted so far at Keta and Ada and aerial
              photographs, could form the basis for the study of the sea level rise.
                   Although dozens of culturally different tribes live in Ghana, the people are
              well integrated into a whole national fabric. The Ghanaian educational system
              is one of the best in the West Africa region, with a literacy rate that stands
              at roughly 30 percent. The government is striving to rehabilitate and strengthen
              the national economy; therefore, many issues have more immediate concern than sea
              level rise.   Educating and informing everyone at all levels of government and
              industry, as well as the general public, of the need to plan and prepare
              responses to rising sea level will be a formidable task.

                   Preparations also will be formidable.      These will encompass the entire
              spectrum of the nation's business: enhancing education, enacting legislation,
              establishing government agency responsibility for oversight or regulation,
              monitoring industry and private sector activity in the coastal zone, carrying out
              scientific monitoring programs, and conducting research to assess impacts of sea
              level rise. Such research must address geomorphological impacts and must also
              provide important information upon which to base appropriate responses to
              socioeconomic impacts. Cultural impacts must be considered as well.

              Property Ownership

                   In Ghana, land is entrusted to the government (local authorities) or to the
              11stool" (kings or chiefs as custodians). Land for development can therefore be
              leased to interested parties by these agencies.

                   The government could only advise people to move as the sea level begins to
              rise and areas are threatened. Experience in Keta and elsewhere has shown that
              people are not very willing to vacate their houses, let alone resettle elsewhere,
              when being threatened by the sea. In most cases, people move out or migrate only
              when their houses have been destroyed by the sea.      There have been instances
              where people have built more than one house that has been engulfed by the sea.


              COASTAL PROTECTION IN GHANA

                   Ghana has protected its coast since the 1920's.

              Bulkheads

                   Steel sheet pike bulkhead was tried in Keta in the sixties.      The average
              depth of the pile was 10 m. Even though this form of sea defense wall was


                                                     100











                                                                                        Abban

           expected to last at least 40 years, it started to fail within 6 years after
           construction and has now collapsed completely.

           Stone Revetment

                Stone revetment in the form of armor rocks has been successfully tried at
           Sekondi.  About a kilometer of road lined with houses has been saved from sea
           erosion.

                Another successful form of stone revetment is the gabion revetment. Tourist
           spots such as Labadi and Elmina have been protected since 1981. A gabion armor
           rock revetment is currently being put in place at kilometer 22 along the Accra-
           Tema beach road to prevent that section of the road from being engulfed by the
           sea.


           Groins

                Wooden groins were tried in Keta several times between the 1920's and 1960's
           without much success.    Pilot gabion groins constructed along the James Town
           Beach, Accra, about 5 years ago appear to be very promising, and they are being
           monitored for eventual adoption along some sandy beaches.

           Sea Outfalls

                A rubble mound outfall structure constructed in the sixties at James Town
           to help with the runoff from stormwater and sewage had no adverse effect on the
           coastal morphological changes in the vicinity.

           Subsidence

                Land subsidence has not been investigated much in Ghana, but there is reason
           to suspect that subsidence might be contributing to the severe erosion occurring
           at Keta.





















                                                  101










                             SOCIOCULTURAL IMPLICATIONS OF
                          CLIMATE CHANGE AND SEA LEVEL RISE
                     IN THE WEST AND CENTRAL AFRICAN REGIONS



                                                0. 010
                                     Departme6t of Geography
                                       University of Lagos
                                           Lagos, Ni geri a



           ABSTRACT

                This paper begins by examining what is presently known about the
           characteristics of climate and climate variations in the West and Central African
           (WACAF) regions and then looks at the socioeconomic and sociocultural
           implications of the environmental impacts of climate change and sea level rise.
           Also discussed are strategies that could be used to reduce or eliminate the
           vulnerability of human settlements and environmental s*ystems, as well as
           socioeconomic and sociocultural systems, to the adverse consequences of climate
           change and sea level rise.


           INTRODUCTION

                Since the beginning of time, the world's climate has fluctuated.      In the
           West and Central African region, for instance, there has been a great variation
           in rainfall, which in turn has affected environmental processes and human
           activities in the region. The impact on geological processes has influenced and
           indeed severely disrupted local, regional, and even global socioeconomic and
           sociocultural systems (for example, natural resources planning and management,
           food production and agriculture, water resources and energy systems, forestry,
           marine resources development, transportation, and tourism).

                There is mounting scientific evidence that human activity is partly
           responsible for changing the earth's global and regional climates. Although it
           is difficult to distinguish between ecological changes due to human activities
           and those caused by natural processes, there- is no doubt that the differences
           in climate between various parts of the earth has in large measure determined
           the types of activities people pursue for both recreational and productive
           purposes.

                This paper examines the impact of climate change on the West and Central
           African regions, with particular focus on the sociocultural implications of the
           greenhouse warming and the rise in sea level.


                                                  103








              West Africa


              WEST AND CENTRAL AFRICA: CLIMATE CHANGE AND VARIABILITY

                    Future climate changes are likely to have a significant impact on the marine
              environment and tho adjacent coastal areas.           The coastal areas of West and
              Central Africa extend from the coast of Mauritania in West Africa to the coast
              of Angola.     Most oF the region is in the tropics and spans the low latitude
              areas between approximately 300 N and 300 S.

                    Annual precipitation varies from less than 200 mm in the north and south
              to over 2,000 mm ir the western equatorial regions, most of the area receives
              between 200 and 1,000 mm of rainfall per year. Of this total, 75% or more of
              the precipitation falls during the rainy season, which lasts between 6 and 12
              months in the central parts of the West and Central African region, and less than
              4 months in the ex-*.reme north and south.        The rainy season is linked to the
              migratory pattern oF the intertropical convergence (ITC), sometimes called the
              intertropical discontinuity (ITD), which is associated with the apparent
              migratory patterns cf the sun (incorporating a time lag of about a month or two).

                    The climate in the WACAF region is also influenced by factors other than
              the ITC, such as atmosphere and oceanic circulation, and land and sea breezes.
              However, little is known about their relative influence.


              IMPACTS OF CLIMATE CHANGES AND SEA LEVEL RISE

                    Climate change is defined here as the change in the mean values of climate
              variables. Climate variability is defined as the differences between monthly,
              seasonal, and annual values of climate parameters and their average values.
              Clearly, it is possible for climate to change without becoming more variable,
              and it is possible to become more variable without the average condition
              changing. Any impact analysis must examine both the long-term climate changes
              and the short-term climate variabilities.         These must be examined over three
              natural time scales: (1) the short-term periods, which range between daily,
              weekly, monthly, seasonal, or annual periods; (2) the medium-term scales, which
              cover a decade or so; and (3) the long-term scales, which span decades or
              centuries (although in the case of nuclear waste sites the assessments span tens
              of thousands of years.)

                    The impacts cr(!ated by short- and medium-term climate problems have made
              the governments and people of the West and Central African regions aware of the
              need to examine their own causative role and to fashion appropriate responses.
              Droughts and f 1 oods - n parti cul ar have caused so much damage that worl d attenti on
              has been drawn to the socioeconomic consequences in the WACAF regions,
              particularly over th,! past three decades. Indeed, there is a growing realization
              that society is vulrerable.

              Ecological and Physical Impacts

                    The average global rise in temperature is expected to be in the range of
              1.50C, to 4.50C, while sea level rise is expected to be between about 20 and 140
              cm. Based on these expectations, it is assumed that both evaporation and
              precipitation will increase by about 2 to 3% for each degree of global warming.

                                                        104









          Thus, it is reasonable to expect that both precipitation and evaporation @jould
          increase, possibly between 5 and 20% in the humid, tropical areas of the MACAF
          regions, which are already too hot and too wet. The increase in both
          precipitation and temperature could have significant environmental impacts. The
          increase in average rainfall may be accompanied largely by an increase in the
          amount of rain per hour during severe storms and shifts in geographical patterns
          of precipitation and cloudiness.   However, since the increase in temperature
          could increase evaporation and potential evapotranspiration, there would be a
          tendency toward more droughts in many, if not most, of these humid, tropical
          areas.   With the increase in ocean temperatures, tropical storms
          hurricanes and thunderstorms) are likely to extend into areas of the region
          where they have been less common. Where tropical storms already occur, more
          intense winds and rainfall might be expected.

              The savanna and semiarid areas of the WACAF region would probably have less
          rain, which -- coupled with temperature increases -- would reduce soil moisture
          availability (WMO/TD, 1988). Less soil moisture, in turn, would diminish food
          production and availability, the availability of water and fuel, and human
          settlements.

              The rise in sea level that would accompany global climate change would
          result in submergence and inundation of the coastal lowland areas. It would also
          lead to increased salinity of the estuarine areas and increase the size of the
          coastal region.

              The ecological and physical implications of climate change include effects
          on geological, geomorphological, and hydrological processes, ocean dynamics,
          droughts and desertification, and floods and erosion, Decreased precipitation
          would lessen the water supply and hydroelectric power generation, @jhfle
          decreasing the risk of floods.      Increased variability could increase the
          probability of both floods and droughts.

              Forest ecology and the ecosystems would also be affected.      For example,
          changes in ecological conditions might be less favorable to the existing biotz.
          Ecosystems would respond by gradually invading the neighboring areas where the
          climate is more favorable.

          Impacts on Agriculture and Livestock Production and Management

              Agriculture and livestock production are the center of life for almost all
          the peoples in the region. The climate and soil characteristics determine hotj
          the land is used for agriculture and livestock production, including which crops
          are grown.

              The impact of climate change and sea level rise on agricultural production
          would no doubt be significant, as would the socioeconomic and sociocultural
          consequences.   For example, decreased rainfall would reduce the production
          potential of the crops presently grown in the various ecological zones,
          increasing hunger in the region and reducing the incomes of farmers and others
          whose occupation depend on farming.   In the extreme, unemployment, starvation,
          and death could also result. There   might also be increased migration to urban


                                                105








              West Africa

              centers for  alterantive employment; and livestock farmers may migrate to other
              areas in search of water for their cattle.

                   Livestock zonos are also clearly determined by climate, particularly
              rainfall. The catt'le zone is essentially determined by distribution of the tse-
              tse fly, which so I'ar has made it virtually impossible to keep zebu cattle in
              the southern reaches of West Africa. Furthermore, these southern reaches have
              been unable to devolop mixed farming even though their heavily leached soils
              could greatly benefit from animal manure. The north is the main cattle area in
              the region primarily because its climate is not hospitable to the tse-tse.

                   Decreased rainfall and drought would affect livestock production in other
              ways.   The productIvity of existing grassland areas, important for livestock
              production, would bo reduced. On the other hand, new grazing lands would emerge,
              possibly shifting livestock production toward the coast. As with reduced crop
              production, income would decline, leading to greater financial stress, which
              could threaten ecoromic survival.     There would also be significant impacts on
              labor, employment, and population distribution.

                   Along the coasts, where sea level rise may lead to submergence of the
              lowland coastal areas (e.g., along the coasts of Senegal and Gambia), much of
              the land currently ised for agricultural and livestock practices would be lost.
              As a result, there would be mass migration out of that area, substantial loss
              of income and great Financial stress, and unemployment. Large-scale resettlement
              would cause additional problems. In a few cases, farmers may be forced to change
              their practices. Because most of the coastal environment would be characterized
              by water surfaces and their associated ecological systems, converting to
              aquaculture may be a viable response (see Everett, Volume 1, Environmental
              Implications.)

              Impacts on Water Resources and Water Resources Management

                   Agriculture, iidustry, and domestic activities depend on water resources.
              Unfortunately, a large proportion of the population in the WACAF regions lacks
              access to adequate freshwater supplies, especially because of population growth
              and rising standards of living which increase water demands.

                    The changes in the magnitude and timing of water resources would
              necessitate changes in management strategies toward greater conservation efforts
              in order to balance water supply and demand. In addition, because most of the
              water resources along the coast would become polluted by intrusion of saltwater,
              water resources management would place greater emphasis on desalinization.

                   In general, the WACAF regions have five types of water supply systems.
              The first category includes areas that depend mainly upon precipitation; unless
              storage is available, these systems are only useful during the wet season,
              usually six months of the year or less.       The second category includes water
              supply systems bas(!d on river flows that do not store significant amounts of
              water for use during periods of deficiency.

                   The third cat(!gory of water supply systems is located in coastal areas
              where precipitatioii occurs during most months of the year.          The impact of

                                                      106









                                                                                          jo

           decreased regional precipitation on this region may be less than elsewhere since
           there would be a general tendency for coastal areas to receive more
           precipitation. However, sea level rise may cause floods and saltwater intrusion,
           which could contaminate water supplies. This would hurt agriculture and might
           even disrupt settlements, with all the consequences discussed in the conference
           report section on social and cultural implications.

                The fourth category of water supply systems consist of manmade reservoir
           systems, which can reduce the effect of intra- and interannual variations in
           preclpttat,lon and runoff. With reservoirs, water is released when it is required
           for agriculture and other purposes. Examples include such manmade lakes as the
           Kainji and Akosombo dzms.    If climate becomes drier, it may be necessary to
           curtail releases of water to maintain needed storage capacity for later release.
           Water shortages in these reservoirs could have considerable financial
           inplications and 7uead to hunger, famine, and death.

                The fifth category of water resource systems consists of those based on
           groundwater resources. In this case, decreased precipitation would lead lower
           water tables and thus increase the difficulty in obtaining water even if the
           total amount of tiater in the aquifer is still sufficient.

           Rmpacts an Other Sectors

                Although the impacts on agriculture and water resources are likely to be
           the most important, other sectors would also be affected, including fishing,
           energy resources, transportation, manufacturing, and construction.

              Uptielling fisheries predominate off the southwest coast of the WACAF region.
           @ncreased global temperatures would warm the normally cold upwelling waters,
           making them unsuitable for the fisheries and causing a reduction in and possible
           collapse of ocean upwelling fishing activities. Tropical warm water fisheries
           would be hurt since a rise in temperature would cause a change in the
           characteristics of the ocean waters and consequently in the habitat of the fish
           currently found in the area. Any significant reduction in the catch would upset
           both the economy and culture of the coastal zone. In addition, wetland loss and
           increased salinity would reduce estuarine fishing.

                Energy supply and demand would also be affected. For example, Critchfield
           (1966) notes that the construction of power lines must always take into account
           a great number of climate effects on the equipment. Strong gusty winds can down
           poles and snap lines, or cause trees and other debris to fall onto the lines.
           An increase in the number of thunderstorms would bring more lightning, which
           causes at least temporary power failure if it strikes a power line. Temperature
           fluctuations can also affect the operation of switches, transformers, and other
           equipment. In warmer weather, lines tend to expand and sag; thus they become
           susceptible to more damage from strong winds.

                Climate change could also have significant impacts on solar energy and
           wind, two sources of energy that still remain untapped in the WACAF region.
           Submergence of the coastal areas would make the onshore development and
           exploration of petroleum more difficult and more expensive.


                                                  107








             West Africa

                  However, of move immediate concern are the possible impacts on the supply
             and demand of hydroolectric power and fuelwood, which is the most widely used
             source of energy in the WACAF region. For example, reduced precipitation would
             adversely affect th(! supply of hydroelectric power, which is very sensitive to
             riverflows.   There might also be problems related to the seasonal aspect of
             riverflows, as well as to the unreliability of rainfall as a source of water
             supply in many parts of the WACAF regions.          Reduced hydroelectric power
             production would imfose economic hardships.

                  The impacts on the supply of fuelwood could also be important. For example,
             with a decrease in precipitation, some sources of the fuelwood would be
             eliminated.   Also, more frequent thunderstorms and erosion could cause more
             damage to the forests.   With a rising sea, the increased landward penetration
             of storms would hurt all but a few (salt-tolerant) tree species, and thus
             decrease the area of forests. If climate change leads people to migrate to a
             particular area, the increases demand for fuelwood in some areas would aggravate
             all the environmental problems commonly associated with deforestation.

                  There could also be important impacts on energy demand. For example, with
             increased temperatures, particularly at night, there would be less demand for
             space heat in the VACAF regions and, consequently, less energy consumption.
             However, if tempera*;ures were higher during the day, there would be greater
             demand for energy to cool buildings.


             STRATEGIES FOR AVOIDING OR MITIGATING THE IMPACTS ASSOCIATED WITH CLIMATE CHANGE

                  The above discu!;sion shows that the impacts of climate change and sea level
             rise are likely to b(! considerable. The question arises: what are the possible
             solutions for reducing or, if possible, eliminating the adverse consequences.
             In general, there are two categories of strategies: (1) avert or reduce the
             magnitude of climate change and (2) mitigate the consequences.

                  The following measures could be used to avert or reduce the magnitude of
             climate change:

                     Reduce demarid for fossil fuels;
                     Adopt technical solutions to collect or control carbon dioxide; and

                     Increase biomass production, which includes the reforestation of denuded
                     areas.

                  Strategies to reduce demand for fossil fuels involve the use of conservation
             measures and alternative sources of energy.       This measure is particularly
             important for developing areas such as the WACAF regions because the relative
             contribution of these areas to the atmospheric gases has been increasing since
             1950. 'Reducing energy demand will reduce burning of fossil fuels. Technical
             solutions, which iiclude the use of mechanisms to control atmospheric
             concentrations of carbon dioxide, are linked to world, regional, and national
             energy policies, forest management, and personal and societal values.         Such
             solutions include measures to control the production and use of coal and
             petroleum and measures to control emissions from power plants or those occurring

                                                    108








                                                                                          Ojo

           at the point of combustion.     The adoption of such measures, however, could
           require complete sociocultural change.

                Increasing biomass production through afforestation will provide a natural
           sink that will absorb carbon dioxide.      Cooper, for example, noted that an
           increase of only 1% in the plant life on earth, especially forests, would be
           sufficient to absorb one year's release of carbon dioxide at the present rate
           (Kellogg and Schware, 1982).    In tropical areas in general, and in the WACAF
           regions in particular, there is a great need to reduce the rate of deforestation
           and to reforest deforested areas.      However, it is important to note that
           reforestation implies ecological changes, which in turn may have climate
           consequences.   Marchetti (1979) has pointed out that a change in vegetation
           patterns could offset the intended cooling by absorbing more solar radiation,
           thus warming the earth.

                Strategies for mitigating the consequences of climate change include those
           that would help to increase human resilience to the effects. Such strategies
           include protecting arable soil, improving water resources management, applying
           agrotechnology, improving land-use policies, maintaining food reserves, and
           adopting disaster response measures.

                In the WACAF regions, there has been a tremendous loss of arable soil
           through soil erosion and salinization in recent years, and this trend would
           probably persist with climate change and sea level rise.     Largely responsible
           for this loss are poor agricultural management practices such as overgrazing.
           Improving water resources management, for example, through effective management
           of dams, aqueducts, reservoirs, irrigation systems, and diverted rivers, would
           ensure adequate and reliable water supply in the event of drought and water
           deficiency.

                Another effective measure would be to develop agrotechnologies such as more
           efficient irrigation systems, saltwater crops, and new forms of nitrogen-fixing
           plants. Improved coastal land-use policies would also be important and should
           be considered in sociocultural planning for mitigating the consequences of sea
           level rise.

                Maintenance of food reserves and adoption of provisions for disaster relief
           now being promoted by international organizations to help the countries adversely
           affected by the recent climate variations, also could help to mitigate
           sociocultural impacts.   The WACAF regions, like any other part of the world,
           require a reliable food supply; since any variation or change in climate and
           consequent sea level rise could adversely affect food production in the region,
           it would be prudent to develop adequate food reserves.

                Other strategies for mitigating the effects of climate change and sea level
           rise involve access to information and technology, which can lead to better
           decisionmaking regarding how best to respond to potential climate change.
           Examples of such strategies include the use of environmental monitoring and
           warning systems, the collection and use of improved data, public information and
           education, and the transfer of technology.



                                                  109








              West Africa

              CONCLUSION

                    Climate change and sea level rise would have considerable implications on
              human cultural systems.      We need to plan and implement the measures necessary
              to either avert or mitigate the consequences. It is important to note, however,
              that usually the sufferer of the consequences sees the causes and effects of the
              problem as wholly ' ocal , and thus thinks only of local solutions. However, to
              effectively plan and implement solutions to the problems that could result from
              climate changes, it is important for local people to base their response
              decisions on a larg,?r world view.

                    We need to ensure that solutions are carried out on world, regional,
              national, and local scales. For the WACAF region, in particular, it is important
              that cooperation, collaboration, and coordinated efforts occur at the regional
              and local levels as well as at the national and international levels. 'To this
              end, national governments must be ready to do their part as appropriate, for
              example, by ensuring that their national observing and communication systems
              function efficiently, and doing more to protect the coastal environment.
              Scientists, planner:;, and policymakers must promote research, provide improved
              access   to data     i.nd  information    necessary    for effective     planning     and
              implementation, prudently use data and information, and support effective public
              participation in planning and implementation of measures to avert or mitigate
              the consequences of climate change and sea level rise.


              BIBLIOGRAPHY

              Critchfield, H.J. 1966. General Climatology. Englewood Cliffs, NJ: Prentice
              Hall.

              Flohn, H.    1979.      scenario of possible future climates -- natural and man-
              made.    In:   Proceedings of World Climate Conference.        WMO No. 537.      Geneva:
              World Meterorological Organization, pp. 243-268.

              Kellogg, W.W., and R. Schware.       1982.   Climate and Society:      Consequences of
              Increasing Atmospheric Carbon Dioxide. Boulder, CO: Westview Press.

              Marchetti, C.     1977.   On geoengineering and the C02 problem.        Climate Change
              1:59-68.

              Maunder, W.J. 1970, The Value of Weather. London: Meuthen.

              Ramanathan, V.     1980.    Climatic effects of anthropogenic trace gases.            In:
              Interactional of Enorgy and Climatic.         W. Bach, J. Bankrath and J. Williams,
              eds. Dordrecht,    Netherlands: Reidel.

              Rotty, R.M.    1979. Energy demand and global climate change. In: Man's Impact
              on Climate.     W. Bach, J. Pankrath, and W.W. Kellogg, eds.           Developments in
              Atmospheric   Science 10. Amsterdam: Elsevier, pp. 269-283.
              WMO.   1979.   World 4eteorological Organization.       Proceedings of World Climate
              Conference.    WMO, No. 537. Geneva: World Meteorological Organization.

                                                         110








                                                                                    Ojo


         WCP. 1986. Report of the International Conference on the Assessment of the Rol e
         of Carbon Dioxide and Other Greenhouse Gases on Climatic Variations and
         Associated Impacts. WMO, No. 661. Geneva: World Meteorological Organization.





















                    MEDITERRANEAN










                     IMPACTS OF GLOBAL CLIMATE CHANGE IN THE
            MEDITERRANEAN REGION: RESPONSES AND POLICY OPTIONS



                                             G. SESTINI
                               Applied Earth Science Consultant
                                        Via Della Robbia 24
                                      50132 Florence, Italy






           ABSTRACT

                Global climate change is likely to have two major types of negative impacts
           on the Mediterranean region: (1) changes of precipitation and soil moisture,
           which will affect water resources, riverflows, irrigation systems, and
           agriculture; and (2) sea level rise, which will exacerbate coastal erosion and
           flooding with repercussions on tourism, settlements, communications, and ports.
           To minimize the adverse impacts of climate change, analyses of these impacts
           should be incorporated into the planning of new projects and activities along
           the coast.

                In most Mediterranean countries, the use of the coastal zone has increased,
           especially for agriculture and tourism.         Unfortunately, development has
           progressed in a haphazard way, with little planning or consideration of
           environmental impacts.    This present state of environmental degradation will
           exacerbate sea level rise impacts.

                The large amount of capital investment along the coasts suggests that
           protective measures will be desired, even though they may not be feasible in many
           cases; thus, the cost of protection will greatly escalate and difficult political
           decisions will have to be made concerning when, where, and how the coast should
           be protected.

                In the meantime, preparation is imperative through increased awareness,
           analysis, regional planning efforts, and regulation in the face of unhindered
           development based on short-term profitability.


           INTRODUCTION

                The impact of climate change on soils, hydrology, vegetation, and on two
           Mediterranean deltaic regions was first evaluated at the European Workshop on
           Interrelated Bioclimatic and Land Use Changes, in the Netherlands, October 1987

                                                  115










             Mediterranean

             (Imeson et al., 198'r; Sestini, 1989). The consequences of temperature and     sea
             level rise for the   coastal areas were further examined in 1988 by a United
             Nations Environment  Programme (UNEP) task team of experts in Split, Yugoslavia,
             which attempted to   forecast changes of climate, sea level, hydrology, ocean
             circulation, marine ecosystems, and vegetation (Sestini et al., 1989, for a
             review), as well as socioeconomic changes (Baric and Gasparovic, 1989).        Six
             case studies have    evaluated impacts on major deltaic areas (Georgas and
             Perissoratis, 1989; Corre, 1989; Marino, 1989; Sestini, 1989a,b; Hollis, 1989).

                  The conclusions with regard to climate variables were that doubled C02 would
             result in a temperature increase of 1.5 to 3.50C; evaporation increases of 15-
             20%; a possible northward shift of the areas of cyclonic activity, with a
             probability of a precipitation decrease        in the southern half of the
             Mediterranean; and magnification of interannual variability, with more frequent
             occurrence of extreme conditions (e.g., heat waves, droughts) (Wigley, 1989).

                  Soils would be affected in their physiochemical structures, particularly
             where rainfall is -:500 mm/year, with greater salinization and reduction in
             organic matter. Soil erosion would increase. Higher temperatures would cause
             a northward and upward shift of vegetation zones, changes in forest composition,
             and greater incidence of forest fires; desertification would increase in the
             marginal areas of limited rainfall.    Agriculture might be affected by changed
             water supplies, decreased soil fertility, and especially by the greater incidence
             of extreme events.     Lagoons and salt marsh ecosystems might change as a
             consequence of greater temperature and salinity fluctuations, with water
             stratification phenomena becoming more frequent.

                  A discussion at the September 1987 UNEP Conference in Norwich, England, on
             the type and magnittide of changes in sea level produced an estimate that sea
             level will rise 14-22 cm by 2030, 25-40 cm by 2050, and perhaps up to 1 meter
             by the end of the 21st century (Raper et al., 1990). Nevertheless, the behavior
             of some of the causal variables (e.g., oceanic thermal expansion and the melting
             of polar ice) are more uncertain than these estimates would lead one to believe.

                  The Mediterranein study also emphasized that (at least in some countries)
             the pressure on the environment from rapid population growth would far outweigh
             the impact of climata change (Baric and Gasparovic, 1989).

                  Two principal effects of climate change stand out for their far-reaching
             consequences and require urgent attention from both scientists and policy makers:

                  1. Coastal instability due to sea level rise, and its attendant negative
                     consequences for lowlands and wetlands, maritime cities, and harbors
                     (e.g., for ligoonal fishing, reclaimed land agriculture, beach tourism,
                     industries, and communications); and

                  2. Precipitation and soil changes and their consequences for slope
                     stability, f)r surface and subsurface waters, and stream and irrigation
                     systems (e.g., for the management of hydropower, irrigation, drinking


                                                   116











                                                                                      Sestini

                   and industrial water supplies, inland navigation, and waste disposal
                   systems, especially in a situation of growing water pollution).


           THE PROBLEMS OF IMPACT ASSESSMENT

                The complex, interrelated nature of the physical -biological systems and the
           present and future population and economic patterns of the coasts and alluvial
           plains (Figure 1) makes assessing the impacts of climate change and sea level
           rise difficult.

                The physical impact of sea level rise on low-lying coasts can be predicted,
           even modeled quantitatively, on the basis of the present parameters of
           morphology, hydrodynamics, sediment budgets, land subsidence, and the effects
           of artificial structures. Likewise, the impacts of altered rainfall distribution
           on surface and groundwater can be modeled, and the effects of increased air
           temperatures and changed soil-water parameters on biosystems can be estimated
           at least qualitatively.    What is more difficult to quantify, however, is the
           impact of these physical and biological changes on the future socioeconomic
           framework of the threatened coastal zones.

                Future organization of these regions (Figure 2) depends on an evaluation of
           the present and future state of the environment; on the side effects of large
           construction projects with a life of decades; on the necessity to protect
           unmovable assets such as historical cities, harbors, and industrial centers; and
           also on the possibility of abandoning threatened areas and/or the redeployment
           of land uses.

                Evaluation of economic impacts must consider not only the present function
           and value of land uses in the context of local needs and of the importance of
           the lowland concerned to its hinterland and farther, but also future land
           functions and values. The primary needs are determined by the present level of
           population and its trends of growth or decline, by the wider economic role of
           the region, and by external market forces. Some economic activities and land
           uses cannot be projected into the future because they are interrelated with
           flexternal" -- economic, social, and political -- factors and therefore can evolve
           independently of local conditions (Figure 2). For instance, the future relevance
           of local industries, agriculture, and ports will largely depend on worldwide
           commodity prices and trade trends such as those related to mineral and energy
           raw materials (with their effects on heavy and chemical industries) and to
           cereals and industrial crops; and on the demand for consumer goods in a
           competitive, exchange-oriented international society.

                The role of ports may change in response to altered trends of maritime trade
           (e.g., the Suez Canal after a decline of petroleum transport), and local markets
           for consumer goods and services could vary in relation to stagnating or reduced
           urban growth resulting from shortages and pollution of surface and ground waters.




                                                  117















                                                     HIGHER TEMPERATURES






                                                                                                                       PROjECTED                                                  PRESENT STATE
                            GREATER               CHANGED                CHANGED                                     TEMPERATURE
                               EVAPO-             SOILS                    AIR               SEA LEVEL                    AND                                                          OF THE
                          TRANSPIRATION           EROSION              CIRCULATUON             RISE                 SEA LEVEL RISE                      NATURA          le         ENVIRONMENT


                                                                                                                                                      MANIPULATED


                         SEA WATER      ECOSYSTEMS      FLOOD
                            TEMP.        PLANTS
                           SALINITY                     RISKS      RAINFALL      STORMS        COASTAL
                           CURRENTS     ANI LS                                                 EROSION                                           A S S E S S M E N T
                                                                                                                   LONG TERM PLANNING            OF FUTURE IMPACTS

                                                                                                                     INVESTMENTS                                                    UNMOVABLE ASSETS
                                                                                                                                                                                    AND INVESTMENTS
                                                                                                                          AND




                                                         SURFACE WATERS
                                                        AQUIFERS RECHARGE
                  00                                                                                                                          LAND & RESOURCES USES                  DEPLOYMEN  TS
                                                        WATER RESO                                                      INTERNAL                                                     NEW APPROACHES
                                                                                                                     SYSTEMS TRENDS



                          FISHERIES    AGRICULTURE                                H RBOURS      BEACH                                                 PROJECTED
                                                      INDUSTRY     COMMERCE      ROADS, ETC    TOURISM                                        ECONOMIC REQUIREMENTS
                                                                                                                                        FP  ROJECTED POPULATION PRESSURE]
                                                  POPULATION. SETTLEMENTS
                                                              AND
                                                  SOCIO-ECONOMIC WELLBEING


                    Figure 1. Some of the variables affecting the assessment                                                    Figure 2. The interrelated nature of
                                      of the impacts of future climatic changes.                                                                  physical and biological systems.
                                                                                                                                                 AMEM E N TS
                                                                                                                                                    S S   S S

                                                                                                                                                 OF FU TORE   IMPACT
                                                                                                                                             EAND &                :US]ES











                                                                                      Sestini

          THE IMPACT OF SEA LEVEL RISE

               Much of the 46,000-km-long Mediterranean coastline rises quickly from the
         ,sea.   There are many alluvial and coastal plains, but each is fairly small.
          Nevertheless, they have been important since ancient times as communication
          pathways for the interior.    Deltas have been generally advancing in the past
          centuries (despite a l- to 2-mm sea level rise and local geological subsidence),
          and until early in this 'century (or a few decades ago in some countries), they
          were in a fairly natural state with extensive lagoons and marshes.

               Today, all coastal plains are intensively used for agriculture, often on
          lands reclaimed from wetlands, with active fishing and aquaculture in the
          lagoons.   Industrial centers and harbors have been established in some areas
          (e.g., Ravenna and Porto Marghera, Venice, Italy; Fos de Mer by the Rhone Delta
          in France; and Abuqir-El Taba by Alexandria, Damietta, and Port Said in Egypt).
          Considerable portions of the Mediterranean coastlines have become more and more
          intensively exploited for beach recreation at the edges of coastal plains or
          between cliffed shores. In fact, in the northern Mediterranean, practically all
          beaches are presently used (utilization ranges from as low as 25% of total
          coastline in Yugoslavia to as high as 75% in north Italy and eastern Spain).
          Tourism development has involved construction of hotels, apartments, pleasure
          boat harbors, and related permanent infrastructures and services. Some resorts
          have become very urbanized (high rises), and old towns have expanded with an
          increase in resident year-round population. Undoubtedly, all these activities
          and settlements would be the first to be threatened by a rising sea level.

               Coastal settlements, from villages to cities, are numerous. However, with
          a few notable exceptions (e.g., Venice, Siracusa), most major cities have only
          small portions at sea level with exposed seaside boulevards and some residential
          quarters at an elevation of I meter or less (e.g., Barcelona, Nice, Marseilles,
          Genoa, Naples, Ancona, Algiers, Pyreus, Alexandria).

               The effects of sea level rise must be considered in conjunction with the
          degree of exposure to storm waves and surges that aggravate coastal erosion with
          seaward removal of sand, direct attack, or overtopping (with flooding) of
          seawalls and dikes. The degree of exposure to wave energy varies with coastal
          orientation in relation to waves (Figure 3). Storms with high waves (2-6 m) are
          generated in the western Mediterranean (and to a lesser extent in the central
          basin) causing wave paths to the northwest, west, and northeast (in the west and
          in the Adriatic Sea), and to the southeast in the eastern Mediterranean. The
          col d and v i ol ent wi nds that bl ow i n wi nter from the north and northeast (mi stral ,
          bora, etc.) generate waves that attack the Algerian-Tunisian, Sardinian, west
          Adriatic, central Aegean, and Nile Delta coasts. All other lowlands and cities
          are more sheltered (e.g., Albania, Turkey, northern Greece) and suffer from a
          smaller degree of storm wave impact.

               Low sandy coasts still in a fairly natural state would probably retreat
          gradually in response to beach profile readjustment (Bruun and Schwarz, 1985)
          with some periodic flooding. The breakup of barrier islands and breaching of
          beach/dune ridges would occur where exposure to storm waves is accompanied by

                                                  119











              Mediterranean








                                                                         DANUBE


                                  RHONE





                           EBR
                                    -Q      VrA
                                                                                        K
                                                                               T  U  R

                                                                                          SE   N
                MOROC                                                                          11@@P
                            A L GE R I





                                                                                               <
                                                                                       L E     0:
                                                                                               (n

                                                                              E G  Y P T

                                                                   A


              Figure 3.  Main deltaic-alluvial lowlands of the Mediterranean region (arrows
              indicate the predominant directions of winter storm waves).


              natural (in some ca!@es also manmade) subsidence or where the coastal sand budget
              is low or negative. Undoubtedly, well developed, thick ribbons of coastal sand
              can survive sea level rise, as indicated by the relic dune and beach ridges on
              the Continental Shelf of the Adriatic Sea and Nile Delta.

                   Wetlands can move landward and grow upward if the rate of sea level rise is
              low. However, the persistence of brackish lagoons and marshes would depend on
              the integrity of the barrier islands, while their ability to move landward is,
              in fact, generally impeded by dikes, roads, and other structures.

                   Many stretches of the Mediterranean coasts are, however, no longer in a
              natural state. Many shores are retreating because dams have sharply reduced (or
              eliminated) the ability of rivers to supply sand to the coast (Figure 4), or
              because people are inining the sand in river beds.  In addition, dunes have been
              flattened to make Yoom for beach resorts.    The natural beach fluctuations and
              coast-parallel sand movements are impaired by fixed defense structures, as well
              as by the jetties that protect the entrances of estuaries, lagoon outlets,
              canals, and ports.

                   The most heavily fortified lowland coasts are in the west Gulf of Lions, on
              the Tyrrhenian and Ndriatic side of northcentral Italy, and in parts of Greece
              I _@





                                                     120











                                                                                     Sestini

          and northern Tunisia.    The other lowland coasts (e.g., Turkey, Albania) have
          fewer coastal protection structures; continued shore erosion in conjunction with
          increased use of the coast will gradually motivate other coastal areas to begin
          empl oyi ng these devi ces as wel 1 , as i n the Ni 1 e Del ta. From a 1 ocal perspecti ve,
          these measures are justified to stabilize harbor accesses and to protect beach
          investments; but when one considers the impacts that protecting one area can have
          on other areas, the wisdom of these measures is not as obvious. All too often,
          people fail to sufficiently consider the future effects of hard structures on
          sediment -starved coasts (e.g., the dikes built at the retreating Rosetta and
          Damietta headlands in the Nile Delta will eventually weaken the lagoon barriers
          to the east).

               A 25- to 30-cm sea level rise would not flood most Mediterranean lowlands,
          but it would worsen the present situation of beach, delta, and lagoonal
          instability. Water levels in lagoons, estuaries, and canals would be higher,
          especially in areas already facing land subsidence (e.g., the Adriatic coast).
          There would be increased salinity in the lagoons, more extended salt wedges in
          rivers, and further salinization of reclaimed lands. All protective structures
          (breakwaters, seawalls, dikes) would have to be raised periodically, and beach
          nourishment schemes would have to be intensified. The cost of beach and urban
          seaside protection will threaten the economic viability of some beach resorts
          and small towns.












                           .9

                                                                        90 412            1(








          0  Cities <1 m elevation,4. surrounded by water
             Cities mostly >2 m, with Parta <1 m UnIharbours)
             Main U impact on port/sknreline infrastructase

          Figure 4. Mediterranean cities that would be most threatened by sea level rise
          in association with storm surges.    Also shown are the main river systems that
          are dammed.

                                                 121











              Mediterranean

                   A further rise of 30-100 centimeters would have catastrophic effects, unless
              measures of artificial protection measures are implemented in advance (e.g.,
              raising and stabilizing dunes, erecting more seawalls, and blocking
              canal s/estuaries and lagoonal entrances with sluice systems).        Recreational
              beaches would continue to exist (along coastal plains if not along cliffed
              coasts), but existing seaside resorts and exposed cities would suffer extensive
              damage. Higher water levels in the northern Adriatic lagoons would cause the
              gradual decline of several historical and commercial centers; these impacts could
              be further exacerbated by other human activities such as withdrawing groundwater.

                   The socioeconomic impact of sea level rise on coastal lowlands will vary
              because the degree Df land use and development varies -- both in absolute terms
              and in comparison #ith nationwide averages (e.g., the Ebro and south Turkey
              Deltas are relative* y undeveloped as compared with the Nile Delta, which contains
              45% of Egypt's population). Few people live below the 1-m contour, even in the
              generally overcrowd?d Nile Delta. Populations are usually concentrated on ground
              more than 2 m above sea level, especially on the raised present or past alluvial
              channels. But thera are exceptions, including Venice, and new recreational and
              port/industrial centers. Moreover, land use will become more intensive because
              of population growti (probably 550 million by 2025, as compared with 350 million
              in the Mediterraneai countries today), and increased tourism (213 million a year
              in 1984, perhaps doubling by 2025) (UNEP, 1987). Recent urbanization on coasts
              has been and will continue to be focused on all available flat ground near the
              sea.


                   In the southeastern Mediterranean countries, populations will grow faster
              and coastal areas will continue to provide focal points for development, mainly
              in the vicinity of' cities.     In North Africa, the nature and extent of the
              economic consequence of sea level rise will depend on the degree and type of
              coastal development during the next 2-3 decades. In Egypt, for instance, the
              economic consequences will depend on the uses made of the coastal lagoons (i.e,.,
              land reclamation, fishing, or freshwater storage).

                   In conclusion, the most serious negative consequences for coastal (in some
              cases national) eccnomies would be the physical impacts on (1) tourist beaches
              and infrastructure; (2) pleasure marinas; (3) coastal protection structures; (4)
              towns and cities b) the sea, seaside boulevards, and residential areas subject
              to washovers; (5) parts and industrial installations, especially those built on
              lowlands and in la(loonal areas; (6) roads, railways, airports by the sea; (7)
              lagoonal fishing; and (8) reclaimed lands and relative irrigation systems.


              RESPONSES AND POLICIES FOR ACTION

                   Responses to -ising sea level would vary from (1) extensive artificial
              protection, to (2) -iltered land use (e.g., less urbanized tourist beach centers,
              the return of some agricultural reclaimed lands back to their lagoonal state),
              to (3) abandonment.     Because the Mediterranean coast is diverse, no single
              solution is likely.


                                                     122











                                                                                     Sestini

                Nevertheless, the intensity of development and the economic value of coastal
           activities suggest that abandonment will be confined to isolated localities;
           however, in many places, public and private investments might gradually become
           economically unviable as increased physical damages make maintenance too costly
           (e.g., polders, infrastructures, tourist harbors, power stations by the sea).
           The Mediterranean coast already has a high degree of coastal defense in many
           areas; the large number of unmovable features (cities, ports, valuable
           agriculture, etc.) would make abandonment expensive. But the escalating costs
           of protection would impose major burdens on state and local governmental budgets,
           perhaps taking up a large percentage of the income generated by coastal
           economies.

                The mai ntenance of beach recreati on f aci 1 i ti es requi res a more practi cal and
           rational approach than that of today. Is the vision of total protection held
           by local residents, private investors, and politicians practical in the long run,
           given the natural processes involved? The present state of degradation caused
           by the very activities to be protected suggest that it is not.         It may be
           unrealistic to continue occupying a retreating sandy shoreline by maintaining
           the existing defense structures. A more rational approach would be to establish
           setback lines and zoning, with less urbanized settlements, and to adopt more
           flopen-space" tourism, wherever feasible, based on the model of the Camargue in
           the Rhone Delta (Corre, 1989).

                With a few notable exceptions of good regional planning (e.g., Gulf of
           Lion), coastal exploitation has been a local or private investment venture (often
           with political backing), whereas the ownership and responsibility for coastal
           use usually are with the state, which has to pay for protection and for the
           damages caused by natural hazards.

                In the face of rising costs of protection, it may be necessary for nations
           to adopt the approach that coastal investments, if carried out with no
           consideration for environmental impact, must be accepted as "high risk," and the
           consequences are to be borne by the investors themselves. (See papers in this
           volume for a discussion of this principle. The concept is parallel with the
           spreading attitude and burgeoning legislation that industrial -urban-agricultural
           polluters must pay for degrading and redressing the environment.)

                Given the continued uncertainty about the timing and magnitudes of sea level
           rise, determining which policies ought to be implemented now is difficult. A
           low level of awareness persists on the part of the public and authorities alike
           concerning the consequences of climate change and the seriousness of -- and the
           need to address -- the present state of coastal degradation.

                It would also seem to be reasonable that countries where the coastal zone
           is still mostly undeveloped should look at the consequences of failing to conduct
           impact assessments, which can be seen in most nations with heavily managed
           coasts.

                Response strategies will depend on the degree of local impact, physical and
           financial, according to present and projected land and water resource uses.

                                                  123










               Mediterranean

               Impacts have, by arid large, yet to be evaluated because data bases are, in many
               cases, limited or itonexistent.

                     Strategies imply long-term planning based on      interdisciplinary approaches.
               Policy decisions based on these strategies will         require political insight and
               the will to carry out 'and implement them; that         .is, they will require a high
               degree of centrali;:ed decision -- in the rather        tight timeframe of just a few
               decades. Even.the first st     ,age, that of deciding   upon and implementing a phase
               of rational studie:; (i.e., to create institutes        and/or to.coordinate ekisting
               ones for environmental impact assessment and planning), is no light task in
               countries where responsibility for environmental matters is dispersed among
               different ministrii?s, -local authorities, universities, and national research
               centers.


               BIBLIOGRAPHY

               Baric, A. and F. Ga,sparovic. 1989. "Implications of climatic changes for the
               socio-economic activities in the Mediterranean coastal zone." UNEP/OCA, Nairobi,
               Rept. WG 2/12.

               Brunn, P. and M.L. Schwartz.       1985.    "Analytical prediction of beach profile
               change in response to a sea level rise." Zeitschr. fur Geomorphologi, Suppl.
               Bd. 57: 33-55.

               Corre, J.J.    1989.    "Implications of climatic changes for the Gulf of Lion."
               UNEP, Nairobi, Rept. WG 2/4E.

               Georgas, D. and C. Perissoratis. 1989. "Implications of climatic changes for
               the inner Thermaikos Gulf." UNEP/OCA, Nairobi, Rept. WG 2/9.

               Hollis, G.E.    1989.   "Implications of climatic changes for the Garaet Ichkeul
               and Lac Bizerte." UNEP/OCA, Nairobi, Rept. WG 2/a.

               Imeson, A., H. Dumont, and S. Sekliziotis. 1987. "Impact analysis of climatic
               change in the Medit,?rranean region." European Workshop on Interrelated Biocli-
               matic Changes, Norwijkerhout Oct. 1987, v.F.

               Marino, M.G. 1989. "Implications of climatic changes on the Ebro delta, Spain.
               UNEP/OCA, Nairobi, Rept. WG 2/3.

               Raper, S.C.B., R.A. Warrick, and T.M.L. Wigley. 1990. Global Sea Level Rise.
               In:   Milliman, D.J. (ed.)       Rising Sea Levels and Subsiding Coastal Areas.:
               SCOPE, Bangkok, Nov. 1988 Seminar (in preparation).

               Sestini, G. 1989a. "The implications of climatic changes for the Po delta and
               Venice lagoon." UNEP/OCA, Nairobi, Rept. WG 2/11.

               Sestini, G. 1989b. "The implications of climatic change for the Nile delta."
               UNEP/OCA, Nairobi, Rept. WG 2/14.


                                                          124











                                                                                   Sestini

         Sestini, G., L. Jeftic, and J.D. Milliman.     1989.  "Implications of expected
         climatic changes in the Mediterranean region: An overview." UNEP Regional Seas
         Reports and Studies, No. 103, UNEP, Nairobi.
         Sestini, G. 1990. The impact of climatic change on two deltaic lowlands of the
         Eastern Mediterranean.    In:  Jelgersma S. (ed.) Sea Level Rise and European
         Coastal Lowlands, Basil Blackwell (in press).

         UNEP, 1988.    The Blue Plan, Futures of the Mediterranean Basin.       Executive
         Summary and Suggestions for Action. Sophia Antipolis, France.

         Wigley, T.M.L. 1989. Future climate of the Mediterranean Basin with particular
         emphasis on changes in precipitation. UNEP/OCA, Nairobi, Rept. G WG/2/6.



































                                                125











                          IMPACTS OF CLIMATE CHANGE ON THE
                     SOCIOECONOMIC STRUCTURE AND ACTIVITIES
                              IN THE MEDITERRANEAN REGION



                                            ANTE BARIC
                           Institute of Oceanography and Fisheries
                                        Split, Yugoslavia





          ABSTRACT

               This paper examines the possible impacts of climate change           on the
          Mediterranean coastal areas, focusing special attention on human settlements and
          major economic sectors (agriculture, tourism, fisheries, and aquaculture).

               Society's activities depend closely on the existing climate. One can assume
          that the impact on activities and institutions will be primarily local, with
          possible important common characteristics for small and large areas or regions.
          However, the assessment of local impacts is outside the scope of this paper owing
          to our lack of knowledge on the particular circumstances facing other regions.

               Climate change will have a limited impact on the distribution and dynamics
          of coastal populations. The natural population growth will not be affected by
          climate changes and will continue to follow the present general trends -- i.e.,
          little natural population growth in the northern Mediterranean countries, with
          high growth rates for nations along the southern and eastern coasts. The current
          rate of migration toward the coast will probably not change, although it could
          accelerate in the south owing to the natural spreading of the deserts.
          Approximately 5 percent of the population living in coastal zones will be
          indirectly affected by the impacts of climate changes and sea level rise; about
          one percent reside in areas that would be inundated by a rise in sea level.

               An inherent quality of most institutions is a certain inertness in response
          to phenomena that are not expected for decades. However, because these changes
          could begin to occur as soon as the next decade, the governments and the public
          should begin preparing for them today.

               The nations of the world should incorporate the mitigation of climate change
          into national development and environmental management.       This calls for (1)
          alerting the public (avoiding unnecessary alarm) and all administrative and
          economic institutions involved in the decision-making process about the possible


                                                 127









              Mediterranean

              effects of the climate changes; (2) studying the I-ocal conditions under which
              these changes will occur; (3) incorporating the implications of climate changes
              into the integrated planning process for global development and development of
              individual economic activities; (4) undertaking     appropriate cost-benefit and
              environmental impact analyses within land-use, envilronmental, and town planning
              and management; and (5) promoting and developing new:technologies for mitigating
              the impacts of climate change.                     . t ,

                   Responding to (limate change will require considerable funds, which should
              be anticipated in national, regional, and local plans.


              INTRODUCTION

                   It is no exaggeration to say that climate largely determines the basis of
              all human activities.      Directly and indirectly, climate affects soils,
              vegetation, water resources, storminess, and most other environmental conditions,
              which in turn help to determine our productive pursuits and the very institutions
              by which society or(lanizes itself.

                   Thus a change in climate would affect the social    and economic structures
              of the entire world in ways that we cannot yet predict. Would the changes be
              sudden or gradual? Should we view the worldwide impact as simply the sum of all
              local impacts, or must the socioeconomic impacts           like the geophysical
              processes -- be viewed in a global context?     Both approaches yield important
              insights, although predicting regional and local impacts is impossible unless
              someone has become -truly familiar with a particular area.

                   Reducing the impacts of climate change im the next century will be
              expensive. New inv?stments will be required for lcoas-tal defense and supplying
              sufficient water tc agricultural areas, or for relocating people should such
              engineering projects be too costly.    The need for new investments may affect
              developing nations in the eastern and southern Mediterranean region particularly
              severely.  New striitegies will be necessary for development, technology, and
              environmental protec.tion.

                   The changes brought about by the greenhouse effect are chronic, while the
              sociopolitical and economic institutions react only1to existing and impending
              emergencies.  Because the complex network of institutions need 20 to 50 years
              to adapt, the planning should already be under way.- In this paper, we attempt
              to evaluate the adaptability of the socioeconomic. activities to a change in
              climate.

              BACKGROUND INFORMATION ABOUT THE MEDITERRANEAN REGION

                   Although the (oastal zones of the Mediterranean countries represent only
              17% of the total area of the countries (Blue Plan, 1988), they are a primary
              focus in assessments of climate changes, given the risk of a rise in sea level.

                   The 46,000 kil )meter Mediterranean coast is very ragged and indented. More
              than half of it is rocky, while the rest is considered to be sedimentary (see
              Table 1). About 75% of the coastline belongs to four countries:

                                                     128
















                                           Table 1. Selected Data for the Mediterranean Coastal Zones


                                                                           Percentage
                                      Urbanized         Population         of coastal                              Length of coastal
                                    coastal zones       in coastal         population          Population/km         shoreline (km)
                   Country            (sq. km)       zones (1,000's)     in urban areas          of coast          total       islands

                   Spain               2,794              13,860              80.64                 5,372            2,500         910
                   France              1,203               5,496              87.52                 3,227            1,703          82
            PO     Monaco                   2                  27             100.00                6,750                 4         --
                   Italy               4,981              41,829              66.76                 5,260            7,953      3 , 766
                   Malta                   13                 383             85.38                 2,128              180          --
                   Yugoslavia            351               2,582              54.38                    422           6,116       4,024
                   Albania                 52              3,050              34.10                 7,297              418          --
                   Greece              1,315               8,862              59.37                    591          15,000       7,700
                   Turkey                371              10,000              53.00                 1,926            5,191          --
                   Cyrus                   20                 669             49.48                    855             789
                   Syria                   17              1,155              35.93                 6,311              183
                   Lebanon                 86              1,668              80.15                 11,867             225
                   Israel                154               2,886              90.35                 21,250             200
                   Egypt                 236              16,511              35.73                 17,300             950
                   Libya                   85              2,284              62.17                 1,290            1,770
                   Tunisia               168               4,965              67.47                 3,819            1,300
                   Algeria               276              11,500              48.00                 9,583            1,200
                   Morocco                 91              3,390              44.89                 6,621                51











               Mediterranean

               Greece, Yugoslavia, Italy, and Turkey. The islands in three of these countries
               account for rough'y 40% of the Mediterranean coast:             Greece, 7,700 km;
               Yugoslavia, 4,024 km; and Italy, 3,766 km (Blue Plan-, 1987).

                     Approximately 133 million people live in coastal zones, representing 37%
               of the total popula-.ion of the Mediterranean countries. About 87 million people
               live in the coastal cities. The gross national product in the region ranges from
               about $700 to $10,000 (U.S.) per capita (Blue Plan, 1988). The distribution of
               gross domestic product varies among the countries (Table 2).           For example,
               agriculture's contribution ranges from 2% in Libya up to 20% in Syria and Egypt;
               industry's contribLtion ranges from 24% in Libya up to 69% in Syria.


               IMPACT OF CLIMATE CHANGE ON SELECTED ECONOMIC ACTIVITIES

               Agriculture

                     Agricultural production in the Mediterranean countries is generally oriented
               toward food, although a few countries also produce tobacco and cotton.
               Cultivated land is less than 50% of the total area of each country; in north
               African countries, it is always less than 10%. In recent times Mediterranean
               agricultural regions have generally remained unchanged, although in Italy and
               France the total ctiltivated land has declined (Blue Plan, 1988).

                     In the northern Mediterranean countries and Turkey, most agriculture is
               removed from the coast, although the high fertility of coastal soils makes the
               coastal zone highly productive.      By contrast, in     the eastern and southern
               Mediterranean countries, production is concentrated in the coastal zone.           In
               Egypt, agriculture is found both in the Nile Delta and inland along the Nile
               River.

                     The expected climate changes in the Mediterranean region (Wigley, 1988)
               could have very far-reaching consequences on agriculture. Sea level rise will
               inundate some area!; and lead to salinization of others. Other factors could also
               be important, such as higher temperatures and changes in the amount and
               distribution of precipitation.

                     Lengthening of the summer dry period may affect the existence of crops or
               plantations, the -incomes of farmers, and the commercial values of products.
               Rising temperatures will change growth cycles, harvest times, and the quality
               of produce; for example, as spring comes earlier in northern Europe, the need
               for early fruits and vegetables produced in the Mediterranean will decrease.
               Warmer temperatures will also have indirect effects, such as increased
               evaporation, lower moisture levels of the soil, and increased erosion.

                     Most plants -equire the greatest amounts of water during the spring or
               summer, which is the period of least precipitation in the Mediterranean.          The
               absence of showers in late spring or early summer may significantly reduce
               productivity or necessitate increased irrigation.        At the same time, warmer
               temperatures will increase water requirements for plants. Wherever possible,

                                                       130


















                                            Table 2. Distribution of Gross Domestic Product


                                            Agriculture                        Industry                           Services
                   Country           1960   1976    1980    1984      1960    1976    1980    1984      1960   1976    1980    1984

               Spain                  21       9      8       6a       39      39      37      34a       40     52      55      60a
               France                   9      6      4       4        48      43      36      34        43     51      60      62
               Italy                  15       8      6       5        38      41      43      40        47     51      51      55
               Yugoslavia             24      15     12      15        45      43      43      46        31     42      45      40
               Greece                 23      18     16      18        26      31      32      29        31     51      52      53
               Turkey                 41      29     23      19        21      28      30      33        38     43      47      47
               Syria                  25      17     20      20        21      36      27      24        24     47      53      57
               Israel                 11       8      5       5        32      43      36      27        57     49      59      68
               Egypt                  30      29     23      20        24      30      35      33        46     41      42      48
               Libya                  14       3      2       2          9     68      72      64        77     29      26      34
               Tunisia                24      21     17      15        18      30      35      35        58     49      48      50
               Algeria                21       7      6       6        24      57      57      53        55     36      37      41
               Morocco                29      21     18      17        24      31      32      32        47     48      50      51

             a 1982

             Source: World Bank, World Development       Reports.





                                                                                                                                   CO











               Mediterranean

               it will be necessary to use closed systems of water distribution and ways of
               supplying water, wiich will minimize evaporation; it may also be necessary to
               reuse wastewaters.

                     Temperature rise may also significantly affect the development of various
               parasites and inseifts, which may directly affect agricultural productivity and
               income.

                     The investmen-;s required for coastal defense, dams, and irrigation systems
               will make agricultural production much more expensive, which could have far-
               reaching socioeconomic consequences. The rich northern Mediterranean countries
               should be able to solve these problems. But the poorer countries in the south,
               which even today have problems with supplying their inhabitants with food, will
               have more difficulty coping.

               Tourism

                     The Mediterranean is by far the strongest tourist region in the world. For
               over 30% of the tcurists that vacation outside their own country, their final
               destination is one or more of the Mediterranean countries. In 1984, about 100
               million people visited the Mediterranean,' of these, 45 million were domestic
               tourists. Althougli France, Spain, and Italy are the most popular destinations,
               tourism is an important part of the coastal economy throughout the region.

                     Mediterranean tourism is primarily oriented toward swimming and sunbathing -
               - activities that directly use the seashore.    2  Therefore, the immediate coast,
                                    3
               its slope, climatE  , and the quality of land and sea are of prime importance.
               Most tourist facilities, such as hotels, camps, and youth hostels, are located
               within 200-300 m @)f the coast.     Facilities farther from the shore are found
               mainly in the developed and luxurious tourist areas.

                     Tourism will suffer from climate change. Beaches that lie below cliffs and
               other rocky inclines would be first to disappear. There would also be problems
               with beaches where infrastructure is within a few meters of the high water mark.
               It may be necessarly to relocate city streets and promenades (e.g., Nice, Cannes)


                     1  This number is probably too low, since most of the countries do not
               accurately regiStEr their domestic tourists (Blue Plan, 1988).


                     ' Mediterranoan tourism fluctuates seasonally. Depending on location, the
               number of visitors from June to September is from 50% to 80% greater than other
               periods of the yei,r.


                     3 Mediterrani?an tourism fluctuates seasonally. Depending on location, the
               number of visitors from June to September is from 50% to 80% greater than during
               other periods of the year.


                                                        132












                                                                                          Baric

          or highways and railway lines (the coastal stretch between Nice and Cannes, and
          parts of the Italian and Yugoslav coasts).

                Even if sea level rises moderately and does not threaten tourist facilities,
          the loss of beaches would disappear or require substantial investments for
          reconstruction.     Moreover, saltwater intrusion due to sea level rise and
          increased evaporation from higher temperatures would diminish the availability
          of water needed for tourism and wastewater drainage. Islands may experience even
          greater damages than the coast of the mainland.

                A special type of tourism, nautical tourism, has stimulated the building
          of a large number of marinas, sport harbors, and berths.         They will be much
          harder hit than the large freight harbors.

                Global warming may lengthen the tourist season in the northern Mediterranean
          by creating more favorable weather.      However, the rise in air temperature and
          sea level may enhance the attractiveness of the continental lakes and of the
          coastal tourist areas of other seas (e.g., Baltic, North Sea), thus negating the
          need for many northern Europeans to travel south for their vacations.

                Any attempts to relieve the impacts of climate changes on tourism will
          encounter great organizational and financial difficulties. The industry has a
          great number of hotels, restaurants, shops, and tour operators, each of which
          respond to their own sets of incentives. Moreover, mitigating the consequences
          would require high public investments in roads, utilities, and other
          infrastructure.

          Fisheries

                Foods harvested from the sea have historically provided an important staple
          in the diets of the inhabitants of the Mediterranean, especially the small
          islands.    With the development of food preservation techniques and faster
          transport, the consumption of fresh seafoods has spread inland.

                About 4 million tons of seafood are produced in the Mediterranean countries
          every year.    The needs of individual Mediterranean countries for seafood are
          basically satisfied through national fishing.           The annual catch on the
          Mediterranean is approximately I million tons.

                Although the total catch has remained constant for about the last 10 years,
          there have been significant changes in the species composition of the catch (Blue
          Plan, 1988). This change has resulted from the overexploitation of some species,
          the demands of the market, and the development of specific new techniques in
          fishing. Looking at individual countries, we find major differences: In more
          developed northern countries, there has been a significant decrease in the number
          of average-quality fish (sardines, mackerel) caught and an increase in the number
          of high-quality fish (mullet, perch, dorade).     In the less developed countries,
          there has been no real change in the catch of poorer quality fish.



                                                   133











              Mediterranean

                    According to some assessments, the present level of fishing is close to the
              sustainable catch, endangering the existing fish stock.        In some regions the
              catch may not be threatening species survival, while in other areas certain
              species are clearly overfished. The consequences at first are reduced catches,
              but eventually the species can disappear (e.g., mackerel in the Adriatic Sea).
              Because sustainabl(! yields themselves will change, better assessments and
              regulation to ensure an optimal catch without overexploitation will be even more
              important in the fa,:e of climate change.

                    It is likely that the expected climate changes will break existing
              ecological balances and chains, and new ones will be formed on significantly
              different levels. "'he Mediterranean region is typical of this problem, because
              it contains species that are heterogeneous in every individual area, the result
              of the vastly differant biotypes. Generally speaking, the weak primary production
              limits fish stocks. Cyclonal activity directly affects the dynamics of water-
              mass movements, esp@?cially in shallower coastal regions.

                    A general decrease of precipitation is predicted for the entire year and
              for the summer pericd.' The resulting increase in the salinity of the sea, along
              with sea level rise, could affect the inflow of nutrients from river runoff or
              from "upwelling" of deep-sea waters. The changes in the physical characteristics
              also could affect the oxygen -solubility in the sea. The changes in the physical
              characteristics cou'ld speed up the physiological processes of marine organisms.
              They also could acc,?lerate the mineralization of organic matter.

                    The rise in the sea temperature in the shallow coastal waters could create
              subtropical or even tropical conditions, which would probably stimulate a greater
              immigration of numerous plant and animal species from the Red Sea through the
              Suez Canal into the Mediterranean region.         Some plant and animal species
              indigenous to the Red Sea have already naturalized in the eastern Mediterranean,
              but in the future they will spread westward.      In contrast, the boreal species
              will be endangered )r may even disappear.

                    These changes could bring about major alterations in the qualitative and
              quantitative composition of the Mediterranean marine flora and fauna.
              Economically important populations of marine organisms will also be affected.
              Climate change also may cause subsequent changes in the migratory habits of fish
              species that constitute the largest part of the annual catch. Likewise, a shift
              in the distribution of niches of some other economically important species may
              require significant modification of existing fishing techniques.           Thi s may
              include new devices and equipment for detecting fish, larger boats capable of
              fishing in farther and deeper waters, and new fishing equipment.          All these
              changes will requirc significant financial expenditures that may depress further
              development of fishing in the economically weaker countries.


                    4 However, in some regions of the Mediterranean, precipitation and/or the
              inflow of freshwater may increase.     Nonuniform changes in precipitation could
              cause very compleK alterations in the physical            characteristics of the
              Mediterranean Sea, aspecially the shallow coastal areas.

                                                       134











                                                                                         Baric

           Aquaculture

                Some countries have tried to satisfy the demand for high-quality fish by
           artificial fish production, although it still accounts for a small fraction of
           total fish consumption. In 1987, approximately 26,500 tons of high-quality fish
           were produced; by 1992, this number is estimated to reach 44,000 tons (Blue Plan,
           1988). About 90% of the present aquatic farming in the Mediterranean occurs in
           lagoons.   Other techniques, for example raising fish in tanks, are being
           introduced in some countries.

                The Mediterranean coast provides great conditions for further development
           of aquaculture.   However, uncontrolled development often endangers the areas
           suitable for aquaculture. If aquaculture is to be notably increased, measures
           for the protection of suitable habitats must be taken immediately. Within the
           framework of the program prepared by the Priority Action Programme of the
           Mediterranean Action Plan in cooperation with the Food and Agricultural
           Organization, ecological criteria for the rational development and protection
           of aquaculture in the Mediterranean coastal regions are being developed, so that
           the Mediterranean countries can in time legislate the proper protective measures.

                Since marine aquaculture is mainly located in the coastal zones, climate
           changes and their direct consequences (sea temperature rise, salinity rise, sea
           level rise) will  greatly affect its development.     Keeping mind the fact that
           marine culture in the Mediterranean comes from lagoons whose average depths are
           only 50 cm, sea level rise may make the lagoons completely unfit for production.
           New lagoons will need to be created or existing ones greatly modified.

                A rise in both the salinity and the temperature of the Mediterranean Sea
           will result in a decrease of oxygen solubility and an increase in the
           decomposition of organic matter. This may enhance the oxygen depletion and may
           even create anoxic conditions.     On the other hand, warmer temperatures will
           accelerate the growth of marine organisms in the colder periods of the year,
           shortening the production cycle.

                The changes in climate conditions may alter the effects of pollutants on
           certain organisms. For example, the expected temperature rise may create major
           changes in the bioaccumulation of certain pollutants, which may negative impacts
           on some commercially important species. Regulations on the acceptable levels
           of water pollution in fish ponds may need to be amended, and some aquacultural
           activities may need to be relocated (see Titus, Problem Identification, Volume
           1, for additional discussion of impacts of sea level rise on fish ponds.)

           Community Infrastructure

                The discussion here on human settlements is restricted to freshwater supply
           and wastewater collection, treatment, and disposal. Although little technical
           data are available on community infrastructure in the Mediterranean region, we
           can anticipate the general impacts of climate change. However, the impacts will
           vary by locality.


                                                  135











              Mediterranean

                   When discussing infrastructure along the Mediterranean, we must distinguish
              between the northern, eastern, and southern areas, and between urban and rural
              units.   Infrastructure is generally most numerous in the cities of the more-
              developed northern countries.       While all northern cities have systems of
              waterworks, most areas in the south do not and some do not even have running
              freshwater.

                   Until recentl), most sewage systems in the Mediterranean released their
              wastes directly to the sea by the shortest possible route.       A large number of
              small systems released wastes immediately under or just at the surface of the
              sea. It was difficult to control these releases, and consequently coastal waters
              became polluted.

                   Recently the philosophy and practice of wastewater management has been
              changing. The general belief now is that wastewater should be collected, treated
              to an acceptable degree of contamination, and then released through a long
              pipeline far into t@e sea. This method of wastewater disposal also allows for
              the reuse of wastewater -- a point of great importance to areas with inadequate
              water sources. Isriiel has not released any wastewater into the sea for the last
              several years; after proper treatment it is reused, mainly for irrigating crops.

                   The expected climate changes will have affect existing community
              infrastructures and require new infrastructures. Basically, the reduction of
              available water wil'I exacerbate present-day problems in many areas. It will be
              necessary to supply some cities and settlements with water from far-away sources,
              since the local sou-ces will have a lessened capacity and poorer quality.

                   Due to the temperature rise, the rate of growth of various microorganisms
              in some water sou-ces will increase, thus increasing possible waterborne
              environmental healt1i risks. Eutrophication may be intensified in some sources
              and rivers. All this will require the construction of equipment and facilities
              for freshwater purification, which will significantly increase the price of
              freshwater -- the p-ice may even double.

                   Sea level rise may endanger the sewage systems in some coastal cities,
              particularly those whose sewage systems also serve as cisterns.        Drainage may
              also be more difficult. After rainstorms, wastewater may flood the lower parts
              of these cities. Both this situation and the shortage of water will require the
              construction of completely new sewage systems and facilities for wastewater
              treatment and possibly reuse.


              IMPACT ON THE DISTVBUTION AND DYNAMICS OF COASTAL POPULATION

                   The current migration toward the coast will continue in the future, but with
              less intensity than irbanization. This latter process will be especially intense
              in the southern and eastern parts of the Mediterranean, where today 40-50% of
              the population lives in the urban areas.      According to the Blue Plan (1988),
              this figure is expected to reach 70-80% by, the year 2025.


                                                      136











                 Chang i ng cl i mate wi 11 have a 1 i mi ted i mpact on the popul at i on I n the coastal
           zone, especially in the initial years of accelerated sea level, rise, assuming
           that coastal defense measures are taken.            The natural population growth is
           primarily affected by other factors, such as the growth of the standard of
           living, the growth of the economic vitality, the level of medical care, and
           cultural and religious customs.        Nevertheless, migration to the coast may be
           accelerated in the south if global warming increases desertification.

                 Urbanization probably will be slower than predicted by the Blue Plan (1988).
           Reduced water suppl i es, poorer water qual i ty, the need for more purl f i ed dr-W n M ng
           water, transport of water from distant sources, plus a greater level of
           wastewater treatment and recycling will require greater expenditures for urban
           infrastructure. The resulting rise in the cost of urban living will slow the
           migration toward cities. The temperature rise will make living in crowded cities
           less pleasant during the summer. The hot exhausts of air-conditioning systems,
           which probably will be increasingly used, also add to the warming in cities.
           A reduction of their use would occur only with a drastic rise in energy prices,
           which may be necessary to limit fossil-fuel emissions.

                 Our preliminary calculations suggest that at least 5% of the coastal
           population -- some 6,700,000 inhabitants -- would be affected by the impacts of
           sea level rise.       Some of these people would be directly threatened with
           inundation, but probably not more than 10-20% of the total number affected. The
           repercussions will include the need to remove structures and construct new one
           for the eventual relocation of the inhabitants.



           CONCLUSIONS

                 Inertia is inherent to economic, social, and political institutions,
           particularly for phenomena that will not manifest themselves in the near future.
           But because recent information indicates that these changes could happen as early
           the next decade, the public and the governments should start preparing for them
           now. Our recommendations are as follows:

                 1. Information should be disseminated to the public as well as to all levels
                    of economic and political decision-making entities about the possible
                    consequences of gradual changes in the climate and the need for measures
                    to mitigate the impact. This should be a national action, not be left
                    to the local authorities or to coastal zones.

                 2. Local inventories should be made of the coastal zones, and data should
                    be collected on the expected local impacts of sea level rise and
                    temperature rise on water,           soil,   precipitation,     and    individual
                    socioeconomic activities.

                 3. A strategy should be developed that can react to changing climate
                    conditions, keeping in mind the accumulative nature of these changes.
                    Calculating expenditures for a given change or given time horizon ignores
                    any additional changes in subsequent years.

                                                       137










              Mediterranean

                    4. The effects of changing climate should be incorporated into the methods
                       of integrated planning, including integrated, economic, land-use,
                       environmental, and town planning issues.

                    5. The cost-benefit analyses and environmental impact assessments should
                       be used to evaluate the feasibility of every expenditure for alleviating
                       the impacts of climate changes.

                    6. Technology !;hould be developed for the alleviation of these impacts on
                       local, regional, and general levels.

                    7. All these activities ultimately should be integrated and coordinated on
                       a regional level.


              BIBLIOGRAPHY

              Blue Plan. 1987. Data Base of the Mediterranean. Belgrade: Sophia Antipolis.

              Blue Plan. 1987. Mediterranean Basin Environmental Data (Natural Environment
              and Resources). Belgrade: Sophia Antipolis.

              Blue Plan.    1988.   :utures of the Mediterranean Basin - Executive Summary and
              Suggestions for Action. Belgrade: Sophia Antipolis.

              Blue Plan. 1988. Futures of the Mediterranean Basin - Environment Development
              2000-2025. Belgradc: Sophia Antipolis.

              Wigley, T.M.L. 1988, Future climate of the Mediterranean Basin, with particular
              emphasis on changes in precipitation.         Geneva:    United Nations Environment
              Programme/OCA/WG. February 6.



















                                                        138










               VENICE-0 AN ANTICIPATORY EXPERIENCE OF PROBLEMS
                                CREATED BY SEA LEVEL RISE


                A. SBAVAGLIA (Chairman Magistrato delle Acque in Venice,
                               Italian Ministry of Public Works)
                      C. CLXNX (Chairman Expert Committee for R & D,
                               Italian Ministry of Environment)
               F. DE SIERVO (Technical Director, Consorzio Venezia Nuova)
                 G. FERRO (Deputy General Director, D'Appolonia S.p.A.)
                                           Via Siena, 20
                                        16146 Genova, Italy





           ABSTRACT

               This paper discusses the social, cultural, and other impacts of increased
           flooding in Venice. It briefly describes Venice's physical , ecological , social ,
           economic, and cultural framework and the characteristics and evolution of
           flooding phenomena. It then analyzes the short-term impacts of the increased
           floodings and discusses the response of the city (and the country) at the social,
           technical, and political levels. The paper next describes the special projects
           being undertaken to prevent floodings, with particular emphasis on the mobile
           gates at the lagoon entrances (whose construction will soon be started), on the
           impact of this project, and on the reactions of the city. Finally, the paper
           attempts to interpret the Venice experience, identifying the features that can
           be considered as representative of generally expected impacts and the reactions
           to sea level rise in seafront cities.



           INTRODUCTION

               Although it is necessary "to consider with great caution casual connections
           (to the earth's climate evolution) often proposed" (Puppi and Speranza, 1988),
           a large number of studies indicate that there is credible evidence for an
           accelerated rise of sea level in the next century.

               The current trend is characterized by an increase of about 10 centimeters
           per century (Gormitz et al., 1982). With respect to this trend, all scenarios
           forecast by different researchers indicate a significant increase. Most of the
           studies forecast a rise in global sea level of between 25 and 75 centimeters by
           the year 2050 and between 50 and 225 centimeters by the year 2100 (Titus, 1986).



                                                  139











            Mediterranean

                 The many consequences expected in coastal areas as a result of sea level
            rise can be classified into three categories: shoreline retreat, flooding, and
            salt intrusion (Titus, 1986). These consequences would affect urban and rural
            areas differently, but in both cases they would have significant economic,
            social, and cultural impacts. All of these have been extensively investigated
            by many authors in mecent years.      Previous assessments have been based on     'a
            priori estimates of 1he impacts, since experience on this topic has not yet been
            acquired. However, few cases exist worldwide that can provide a valuable insight
            into the phenomenon.    Among them, Venice represents an extremely significant
            experience.

               . Since the beginring of this century, the relative mean sea level in Venice
            has risen by about 2!; centimeters, and the mean number of floodings of the city
            has increased from less than 10 to more than 40 per year.             Catastrophic
            floodings, having a return period of 800 years at the beginning of the century,
            presently have a return period of 200 years; that is, a 25-centimeter rise
            quadrupled the risk of serious flooding.      For these reasons, the problem of
            protecting the city from the sea has taken an increasingly urgent priority, and
            in such a way Venice represents the likely economic, social, and cultural impacts
            that sea level rise would have on an urban environment.

                 This paper illLstrates the Venice experience in order to provide some
            indication for future, possibly more generalized situations. It first briefly
            describes Venice and its environment and provides a short history of sea level
            rise. It then analy2es the perception of the problem, discusses the short- and
            long-term reactions, and presents the course of action that officials have
            selected.   Finally, it illustrates future perspectives and critically reviews
            the Venice experien,:e, outlining the most prominent aspects likely to be
            experienced by coastal communities in general as sea level rises.


            VENICE AND ITS ENVIRONMENT

                 The Venice lagoon is the most important remnant of a series of lagoon
            formations that, thoijsands of years ago, occupied all the northern bow of the
            Adriatic. It is made up of a basin of 550 square kilometers, and is connected
            to the sea by three openings at Lido, Malamocco, and Chioggia (Figure 1). The
            basin has an oblong and arched shape and extends about 50 kilometers along the
            Adriatic coast, varying from 4 to 15 kilometers in width, with an average depth
            of about 1.5 meters.

                 One portion of the lagoon (420 square kilometers) is permanently submerged
            by water (shallows); another is permanently above the water (islands and
            urbanized areas). 01' the remainder, one part (the "barene") is submerged only
            by normal tides, while another part (the "velme") is generally submerged and is
            above water only during very low tides. At the edge of the lagoon, 90 square
            kilometers of water are reserved for fish farming. Figure 2 illustrates various
            parts of the Venice lagoon.



                                                   140









                                                                                                        Sbavaglia, et al.




                                                                                                            ...............
                                     X
                                                                         X
               ...... ....
                                                                       .. . .... .estre                                              . . . . .
          X    . . . . . . .   . . .
                                                                                                     X.
                                                                                                       . . . . . . . . . . . .
                      .. . . . . . . . . .                   . . . .
               .. . . . . .. . . . . . . . .                                                                   . . . . . . . . . . . . . .. . . . . . . .


                                                                   X


                                                    YA

                                                                                                                         -X -:-X
                                                                                                                               ... ........
      N
                                                                                                                      ........ ...%
      ...                                                                                                              ...             ....
                                                                                                                                  X.X.X.Y.
                                                                         ,V E N E Z I   Murano
                                                                                                        Torc_                            X
          X



                                                                                        .:X:
                                                                                            *XY.
                                                                                               X
                                                      Porto di Malamocco
                                                                                                ' *:::      .
                        h'o 1 a
                                                                                  Porto di Lido




                          Porto di Chioggla
               X-X
                                                  MARE ADRIATICO                                         5 krn




               Figure 1. Map of the Venice lagoon.


                      The evolution of the Venice lagoon has been reconstructed on the basis of
               geological studies. About 10,000 years ago, the sea level began to rise and the
               coastline migrated north from the lower Adriatic. When it reached approximately
               the present location (about 6,000 years ago), an intense and prolonged alluvial
               phase took place.           Sediment flowed into the sea and was distributed along the
               coast by the wave motion and the sea currents, forming the littoral line that
               delimited the primitive Venice lagoon (albeit with a smaller extension than the
               present one).

                      Among the factors affecting the lagoon's morphology during the ages, the
               activity of the lagoon's tributaries was dominant. They kept the water brackish
               (rather than salty), but they also threatened to make the entire lagoon a
               marshland and eventually to fill it completely.

                      The lagoon is an extraordinary environment to be conserved and protected,
               with a balance between the natural beauty of the place and the needs of the
               communities living there.                Several hydraulic works have been carried out to
               preserve it, particularly the diversion of major tributaries into the sea, the
               location of the sea entrances, and the dredging of channels for inland
               navigation.

                                                                      141











                       Mediterranean
















                                                                                                                                      low
                        511,





                                                                                                      *01



                                       - 1 41


                                                    1
                                                     Nw-
                                                     1"



                                                     -Am








                       Figure       2 (A). Historic Venim

                                                                                            142



























                                                                                                     IL



























                                                                                            Am    1








              Mediterranean

                                            'Z7 "'7

                                   Z 1
                 . . ..... .. .....   14-@I,,;





                              1"ev'Un,
                                                              mxg,                        v4
                                                                UNA
                                                            M'V 9-1,
                                                                                     oWiWR_'Z*VA1 $N41141k "taw-
                             L "'A
                                                                                          01
                                                                                                 :OV,
                                                                                             Z



                           "o"M,

                                                      U2

                                                                                      TW
















                                           "N"ANZ,











              Figure 2 (D)    Aerial view of a low-tide    inlet of the Lagoon of Venice.     The
              strips of land  that emerge at low tide are  a distinctive feature of the lagoon.
              They have a very important hydraulic and     ecological role; they can attenuate
              currents and wave motion, and so help to control two of the causes of the city's
              decay.


                   The Venice lagoon is characterized by networks of deep natural channels to
              the mainland, which branch out of the three openings. Other manmade channels
              have been operated over the centuries to improve navigation within the lagoon,
              and two large channels have been created in recent times to house shipping to
              the industrial Port of Marghera: the Vittorio-Emanuele Channel (1926) from the
              Lido opening, and the San Leonardo Channel (1968) from the Malamocco opening.
              Tides propagate primarily along these natural and manmade channels.

                   To allow ships of increasing tonnage to enter the lagoon (for military and
              commercial reasons), as well as to avoid the frequent malaria caused by stagnant
              water, the Venetians carried out, between the 16th and 19th centuries, a complex
              series of works to redirect the course of rivers such as the Brenta, Piave, and
              Sile, so that they came out into open sea rather than within the lagoon. In this
              way, the flow of freshwater into the lagoon      was reduced, and the rivers no
              longer carried sediments into the lagoon, which in the long run would have caused
              the basin to silt up.

                                                      144









                                                                         Sbavag7ia, et a7.

               Other internal defense measures were undertaken against the major external
          threat represented by the sea.     In the 18th century, the "Murazzi," massive
          seawalls performing their function even today, were built to protect the shores
          from flooding by high tides. Between the 19th and 20th centuries, breakwaters
          were also built to prevent the silting up of the three openings to the sea. As
          a result, the tidal flow between the sea and the lagoon was increased along with
          the speed of the tides in the internal channels, leading to noticeable changes
          in the physical characteristics of the lagoon.       These changes were further
          emphasized by the two large shipping channels opened during this century. For
          the Venetian lagoon, therefore, the problem has always been one of maintaining
          the equilibrium between the natural and human environments.

               The presence of human settlements in the lagoon has made the ecological
          balance even more complicated, and so the search for an equilibrium between the
          various needs of the environment is becoming increasingly difficult.           The
          movement of the sea is essential to the renewal of the lagoon's waters, removing
          human, industrial, and agricultural waste, but stronger tides must be controlled
          to avoid both flooding of inhabited areas and erosion of the "barene," which
          would silt up the channels.


          SEA LEVEL RISE IN VENICE

               From the hydraulic point of view, the complex system of the Venice lagoon
          can be subdivided into (1) the basin of Lido, or the northern lagoon; (2) the
          basin of Malamocco, or the central lagoon; and (3) the basin of Chioggia, or
          the southern lagoon. Each of these three basins is connected to the northern
          Adriatic by inlets, known as port openings. The three port openings have a total
          cross-sectional area of approximately 18,000 square meters, and for each tidal
          cycle about 330 million cubic meters are exchanged.

               Approximately 430 square kilometers of the lagoon are open to tidal
          expansion, which flows into the lagoon through the three openings along the 800-
          kilometer network of channels.    These channels wind across shallow waters and
          11velme" (areas of the lagoon usually covered with water), islands, and "barene,"
          and their depth and width gradually decrease as they reach upland to the extreme
          borders of the lagoon. Excluding fish farms, 75 percent of the area subject to
          tidal expansion is between 0 and 2 meters deep, whereas only 5 percent exceeds
          5 meters, as is the case of the deepest channels.

               In this natural environment, with largely urbanized areas, the phenomenon
          of exceptionally high tides is taking place with an increasing frequency, thus
          becoming a real threat to Venice and its lagoon. High tides are often determined
          by the coincidence of various factors:       the normal astronomical tide, the
          scirocco wind that drives waters of the Adriatic to the north, the sea level
          fluctuations due to different atmospheric pressures at each end of the Adriatic
          (seiche), rain on the catchment basin drained by the lagoon, and finally the
          seasonal variations in the level of the Mediterranean Sea.




                                                 145










             Mediterranean

                   The frequency and severity of tidal floods increased in this century as a
             result of sea level rise due to the melting of world's glaciers, and as a result
             of land subsidence-due to natural settling and the drawing of water from artesian
             wells.

                   Land subsidence, which is also caused by natural factors, played a major
             role in the origin and evolution of the lagoon, and has become a determining
             factor affecting the city and lagoon environment after human intervention.
             Anthropogenic subsidence initially started with the heavy groundwater pumping
             used mainly for industrial purposes.    Intense pumping of groundwater resources,
             which is the main cause of Venice's sinking, mainly occurred between 1950 and
             1970. Since the progressive reduction in artesian water consumption started in
             1970, the piezometric levels have moved back to their original values, and by
             1978 the natural aquifer pressure had been reestablished.

                   Aquifer depletion and subsidence ran parallel courses between 1950 and
             1969-70. Both reached their peak values in 1969, when subsidence was reported
             to be 12 centimeters in the industrial zone and 10 centimeters in Venice. With
             the reduction in consumption and further natural recovery of aquifers after 1970,
             the land survey of 1973 showed subsidence to be slowing.      A small rebound (of
             the order of 2 centimeters) in the historical center was measured during the 1975
             survey.

                   However, human-induced subsidence was not the only factor causing more
             tidal floods in the lagoon:      natural subsidence and global sea level rise
             (eustacy) also contribute to the diminishing land surface level of the city with
             respect to the sea level, thus increasing the impacts of high tides (Carbognin
             et al., 1984).

                   Leveling measures from before and after groundwater exploitation -- i.e.,
             between 1908 and 1980 -- suggest that the present natural subsidence is about
             half a millimeter per year.    This annual average rate is appreciably lower than
             the average rate of about 1.3 millimeters per year estimated with reference to
             the last millennium.

                   Eustacy has affected the water level of the lagoon due to its connection
             to the Adriatic Sea. From the beginning of this century, the sea level has been
             rising 1.27 millimeters per year.

                   These three factors (human-induced subsidence, natural subsidence, and
             global sea level rise) and their effects on the Venetian environment are depicted
             in Figure 3. The period 1908-80 includes the different stages of land sinking.
             The aforementioned anthropogenic subsidence lowered the land an average of 10
             centimeters, netting out any rebound.

                   In conclusion, these three factors have lowered the surface level with
             respect to sea level by about 22 centimeters from the beginning of the century.
             Today the mean elevation of the land surface of the city is about 110 centimeters
             above mean sea level, while 80 years ago it was nearly 130 centimeters. This
             loss of 22 centimeters has caused Venice to flood more frequently.

                                                     146









                                                                         Sbavaglia, et a7.



                  E
                  S`8,

                  F
                    6.
                  r
                    4.

                    2
                    0@
                  Uj
                                                NATURAL  SUBSIDE14CE
                    2.                 @S u b's'i'jdre n c e                          C
                                                                                      .T
                    4.                                    Induced byMan               .2
                  C


                  W 8.
                  can) 0.                                                             j2

                  Ca 2.
                  0
                    4.

                         Natural Trend I Period Influenced by Hui*an Acti ity
                              igio            19@0           196b            1960


          Figure 3. Eustacy and subsidence trend.


               Parallel to the rise of relative mean sea level, high tides have increased
          as well. Figure 4 shows the increase of the annual mean level of high tides (as
          well as of low tides) from 1920 to 1980. In Figure 5, the number of high tides
          for height classes (for each 10 years from 1955 to 1985) is presented.         The
          increasing number of exceptionally high tides is clearly indicated.            For
          instance, between 1931 and 1945, eight exceptionally high tides took place,
          reaching or exceeding 1.10 meters above the average sea level; whereas between
          1971 and 1985, with the increased subsidence due to human interventions
          subsequently interrupted, forty-nine high tides were recorded.

               As Figure 6 shows, Venice is extremely vulnerable to sea-induced flooding.
          When water levels are 70 centimeters above zero (relative to the Punta della
          Salute hydrometer), St. Mark's cathedral is flooded; at 80 centimeters, water
          pools appear in St. Mark's square; at 90 centimeters, the square cannot be walked
          through any more and begins flooding the lowest streets ("calli"); at 140
          centimeters, more than 60 percent of the city is flooded. In the period 1920-50,
          the tidal level exceeded the "critical threshold" level of 80 centimeters 15
                                                                 rity










          times a year. This threshold has been exceeded, on the average, 25 times a year
          in the period 1950-60, and 50 times a year since 1960. Exceptionally high tides
          (e.g., greater than 140 centimeters) have become more frequent as well. Looking
          back to history, during the preceding seven centuries the Republic of Venice was

                                                 147








                               Mediterranean



                                                       60--





                                                       40--

                                                                     a




                                                      20




                                                                     M
                                                    -0-                . . . . . .                                   - - - - - -         . . . . . .        . . . . . .




                                                    -20--            b



                                                    -40-                                                                             1               i               i
                                                                  1920           1930             1940            1950             1960            1970            1980




                              Figure 4. Annual average high (a), mean (m), and low (b) tides.

                                                                                               (,,Ware Of                                                                  640  P4EA, '@-arQ


                                                                                  ago                                                                                            120





                                                                                                                200
                                                                                                                Iso                                                                                      ISO

                                                                                                                '00




                                                                                                                                                                                                   Q1






                                                                                             100


                                                   C41

                                      a) HIGH         TIDES
                                                                                                                                                                             b) LOW TIDES
                              Figure 5. Number of high tides for height classes.
                                                                     a
                                                                     V,

























                                                                                                                      148









                                                                          Sbavaglia, et al.

          subjected to fewer exceptionally high tides (51) than in the 52 years between
          1914 and 1966, when it experienced 53.     Figure 7 illustrates the area flooded
          by tides of 1 to 1.9 meters.


          PERCEPTION AND SHORT-TERM EFFECTS

               Venice has always been a sea-town, organized and subordinated to the lagoon
          environment. Its economy was based mostly on shipping. Water was an essential
          factor of life.    It simultaneously meant refuge, safety, nourishment, income,
          and prospects for development. As an example, until 1300 there were no streets
          in Venice: its channels were the only transportation system, and the boat was
          the only transportation facility in town.

               Though Venetians became allied with the lagoon water to build their "living
          environment" on the archipelago, practically in every age calamities have been
          reported periodically affecting the town. An exceptionally catastrophic event
          occurred on November 4, 1966, at the time of a big flooding of the Padana Plain
          by the Po River and of the city of Florence by the Arno River:         a tide 194
          centimeters above average sea level was recorded. More than 4,000 ground-floor
          apartments were inundated, and more than 13,000 people lost their homes.       The
          tide devastated shops and storerooms, caused an electric blackout, and cut off
          gas supplies and telephone connections.

               Although the problem of rising sea level was already studied and discussed
          by a few specialists in the fifties and early sixties (e.g., Miozzi, 1960), at
          that time the problem was basically ignored by public opinion and the political
          groups. The main issues at the beginning of the sixties were the industrial and
          urban development of the city and the surrounding area.

               The situation suddenly changed after the catastrophic 1966 event. The high
          tides ("acque alte") immediately became the central problem of the public debate.
          The impact was enormous, not only in Italy but worldwide, and committees to "Save
          Venice" grew up all over the world. The event, defined by an author as being
          "cruelly beneficial" (Miozzi, 1968), also gave a substantial impetus to the work
          of the interministerial committee "Per lo Studio dei Provedimenti a Difensa della
          Citta di Venezia," set up in 1963 and practically inactive until then.

               The high tides continued in the years after 1966 (basically at the same
          level as during the years immediately prior), and the press gave them extensive
          attention. In 1970, a public body was set up to predict high tides.

               Meanwhile, the program for protection proceeded slowly. The slowness of
          the interministerial committee that was supposed to coordinate the operations
          exasperated the citizens.      The Venetians protested and organized symbolic
          demonstrations of disapproval of the city's administrators.

               In 1971, seven proposals for a special law for Venice were presented within
          eight months.     Finally, after endless discussions and a large number of
          amendments, on April 16, 1973, the Special Law (Law 171/73) was approved.        It

                                                  149









                                                                                 Sbavaglia, et 0.
                A







                                                                 T












               B                                                              . .. . .. ..... . .








                                                                                         @ @ ml_

                  @i O@r@



              Figure 6. Flooding in Veni    ce: (A) San Marco Square under flood water in 1987,
              (B) and during the exceptional flood tide of 1966.

                                                        150







     C

                                                                        Sbavaglia, et a7.















                                                          PT







                    Al


           Oz
             tv,

































                                                                                         V




          Figure 6.  Flooding in Venice (continued):    (C) Venice during  the exeptional
          flood tide of 1966, (D) damage to buildings produced by the combined action of
          high tides and wave motion.

                                                151










                                 zz '@a*'




                         ti

                                                                                              "'M
                                                                    w@



















                                                                 IS          IC
                                                                      @q'
                                    -I         KRI "'ZjF@'              N,
                                                                 CS  4 'S N


                                                                         N
                                                                   1  1441


                                                                                           41

            B
                          M
               A        M"'tit as

                                                 7"'a'
                     VIV
                                                                                           Z-,
                     gTg                    W=


                                                                       ,4.V'M"@



                                                                    " M7.-
                                                               IB
                                                                                    'R,






                                                          k'24 1*4 t

                                                                  Mi



                               00
                                                                                       '"44
                                                                          -4- V
                                                     tin'
                                        d
                                        'M
                                  pil", @U



                                                                                     VNI


             Figure 7. The shaded   areas show  the portion of Venice flooded by tides   of (A)
             I m, (B) 1.1 m, (C) 1.2 m, and (D) 1.9 m. Assuming no change in storm frequency,
             these areas will be underwater 50  times a year for rises in sea level of 20, 30,
             40, and 11 0 cm, respectively.
                               M Or




































                                                    152








                                                                         Sbavaglia, et al.







             T@




               11Z




















          D
























           Figure 7 (C and D).

                                                 153











              Mediterranean

              established that the national government should take care of the physical
              safeguarding of the lagoon and urban areas; the regional government would be in
              charge of planning activities; and the      city government would manage the
              restoration of the historical center. The  planned response measures have four
              objectives: the physical safeguard of      the lagoon, decontamination, the
              restoration of monumental and smaller buildings, and the economic development
              of the Venetian area. The law also provided financial support of 300 billion
              lire (about 3 billion U.S. dollars). At that time, many people believed that
              most of the problems were over. However, the long path toward the protection
              of Venice from high tides was just beginning.


              LONG-TERM REACTIONS

                  Since the Venice program started in 1973, the people became more and more
              accustomed to the periodic flooding of the city, intensifying public commitment
              to a solution.

                  To carry out the 1973 Special Law, an international bid was issued (Law
              404/75) to solicit proposals for implementing the Special Law. Five groups of
              well-recognized companies submitted their proposals, but none was considered
              adequate (March 1978). Then the Ministry of Public Works was authorized to buy
              the projects submitted (Law 56/80).     The Ministry commissioned a group of
              internationally recognized experts to draw up a plan of action to protect the
              city from high tides.   The plan was based mainly on the idea of temporarily
              closing off the lagoon at the three openings, using barriers that were in part
              fixed, in part mobile. These would normally be left open and closed only when
              necessary.

                  The project drawn up by the experts was approved in 1982 by the Supreme
              Council of Public Works, which established that the work should aim, above all,
              to achieve these primary objectives:

                      the reduction of flood tides in the lagoon;

                      the guarantee that a sufficient renewal of the lagoon water would be
                      maintained to prevent a worsening of the water pollution;

                      the maintenance of the three openings at Lido, Malamocco, and Chioggia
                      as viable port entrances, limiting closures to a minimum.

                  To carry out intensive studies of the area, test possible solutions, and
              then plan and carry out a complex series of measures that should meet the needs
              of both the environment and the tourist, commercial, and industrial activities
              that are now part of it, the Italian Government has entrusted the Venezia Nuova
              Consortium.

                  The project drawn up by the experts in 1981 suggested, as a solution to
              the problem, the installation of mobile gates set in fixed barriers.         The


                                                    154









                                                                          Sbavaglia, et al.

          barriers made it possible to reduce the effects of excessively high tides, but
          they also permanently reduced the exchange-flow between the sea and lagoon.

                The "Venice Project" has as its primary objective the conservation and
          development of the city of Venice, and of its lagoon, which is a unique
          ecosystem. This obviously requires controlling the high tides. The difficulty
          arises from the impossibility of closing off the lagoon from the sea for long
          periods of time. The tides have a fundamental role in maintaining the life of
          the lagoon environment. Even a simple reduction in the exchange-flow could have
          consequences that should not be underestimated (see Park, Volume 1).

                The series of operations to safeguard Venice was given its clearest
          definition in Law 798 of November 29, 1984.

                In 1982, the Magistrato alle Acque charged the Consortium with the task of
          carrying out studies and producing mathematical models of the lagoon.         These
          studies were to focus on reestablishing the hydrogeological equilibrium of the
          lagoon; arresting and reversing the process of decay within the lagoon by
          eliminating its causes; reducing the level of the tides in the lagoon; defending,
          with specific local measures, the islets that make up the city center; and
          safeguarding the urban areas of the lagoon from flooding by means of mobile
          gates at the three openings to regulate the tides. The work of the Consortium
          actually started in 1986.

                To finance this first stage of operations, the law set aside 234.5 billion
          lire (almost 2 billion U.S. dollars). The funding for the following studies was
          to be guaranteed by the budgets from the fiscal year 1987 onward. An updated
          estimate of the cost of the work is 3,300 billion lire.


          THE PROJECT AND THE PROBLEMS

                To protect Venice and its lagoon from sea level rise, the only possible
          solution is the control of tidal flow at the port openings.    In compliance with
          Law 798, the solution that has been found most suited to the conditions and needs
          of the lagoon environment consists of a system of mobile structures for the
          regulation of tidal flow.

                The project envisions the use of specially designed gates,   respecting the
          typical conditions of the lagoon system from the viewpoints of both the
          environment and socioeconomic development.      For each port opening, a set of
          rectangular flap gates will be installed; these will be hinged to a foundation
          structure made of cellular-reinforced concrete caissons.

                Each gate -- i.e., each module -- is 20 meters wide (Figure 8). In their
          "off" position, the gates are flooded and lie horizontally in a recess in the
          foundation structure. If necessary, by expelling part of the water they contain,
          the gates are lifted to their operating position (at an angle of 45 degrees with
          the horizontal) to stop the tidal flow. The gates have no intermediate piers
          to hold them in their operating position and, therefore, oscillate freely under

                                                  155










                               Mediterranean










                                                                                    0 F l--j-Jl

                                B

                                                                                                                                                          -AA 0-




                                                                                                                                                         ;i,A:


                                                                                                                                                                    @,,tzj
                                                         v
                                                                                                                                                    ax
                                                                                                                                               lw@
                                                                                                            Mg
                                                            PEI;









                                                                                                                                                                                                        t!
                                                                                                                                                                                        Itz,!tt :1`111,
                                                                                                                                                                                    , 4`4",
                                                                                                                                                                                                "p,
                                                                                                                                                                                     -0
                                                                                                                                                                          IZI
                                                                                                                                                                            - -                                        4! 2,1464


                                                                                                                                                                                                         :W,




                                   Figure 8.                  (A) Schematic illustration of the mobile gates and (B) gate                                                                                        being
                                   towed past San Marco.

                                                                                                                            156









                                                                           Sbavaglia, et al.

          the action of the waves, which are transmitted, practically unaltered, to the
          lagoon.   The compliance of the gates with the waves drastically reduces the
          forces transmitted to the foundation structures, thus simplifying their
          construction and reducing costs as compared with more traditional solutions.

               In normal conditions, when the gates are open, the port openings are free
          from any structure.    Therefore, there are no obstacles to either water flow or
          navigation.    There will be no aerial superstructures, either temporary or
          permanent, since these would alter the,landscape and could hinder the transit
          of ships.

               Although strongly requested after the 1966 event, the project for the
          temporary closing of the lagoon has encountered increasing public opposition.
          A strong environmental concern grew, fed by the tremendous environmental
          degradation of the lagoon.    Fear was expressed that the closing of the lagoon
          could reduce the water exchange and further worsen the environmental problems.
          In view of the rise of the "green movement," increasing attention was devoted
          to those concerns, and a number of additional detailed studies were performed
          by the Venezia Nuova Consortium to investigate these problems. However, a final
          approval of the project is still pending.

               In the same period, the interministerial committee, set up by the Law
          798/84, recognized the pollution of the lagoon as a major problem and started
          a restoration plan.    The guidelines for the restoration plan were approved by
          the Committee in October 1989.

               Updated estimates indicate that the total financing needed for safeguarding
          and restoring Venice and the lagoon will most likely reach some billions of
          dollars.



          CONCLUSIONS

               During this century, Venice has experienced a significant increase in both
          the frequency and the magnitude of periodic floodings. This is due to a number
          of different simultaneously occurring causes (particularly mean sea level rise
          in the Adriatic Sea and land subsidence due to uncontrolled exploitation of the.
          water table). The experience of Venice has many similarities with the expected
          effects of the sea level rise on other seafront cities, at least in a first
          stage.

               However, although the Venice situation represents a very interesting case
          study, some of its peculiarities must be carefully considered:

                   its physical characteristics -- i.e., the presence of the lagoon between
                   the sea and the inland environments;

                   its sociocultural implications, since the sea-town of Venice always
                   tried to manage the lagoon environment not only by integrating itself
                   with the element "water" but also by developing its organization "on
                   the sea"; and

                                                  157









              Mediterranean

                       its political and economical peculiarities, being a "unique" town
                       worldwide and having available large financial resources.

                    Some interesting conclusions can be drawn from the Venice case study:

                    ï¿½  sea level rise (although of limited extent) represents a critical
                       problem for the town;
                    ï¿½  the problems were recognized for a long time by the scientific community
                       and were outlined to the public administration, but interventions were
                       started only following a catastrophic event;

                       the definition and implementation of remedial measures required a very
                       long period of planning and study, and after 20 years real work still
                       has to start;

                    ï¿½  some years after the catastrophic event, Venetians started to accept
                       the floodings as an unavoidable phenomenon in its particular habitat;

                    ï¿½  as time passed, other issues started to be considered essential for the
                       remedial measures (environmental conservation, city development, etc.),
                       slowing down the initial rate in the development and implementation of
                       the remedial measures; and

                    ï¿½  remedial measures need very large financial resources, that in general
                       can be collected only from the national government.

                    From a more general point of view, the Venice case can provide some
             guidelines on the following:

                       the need to focus in advance public attention on both the primary and
                       secondary effects of the sea level rise phenomenon;

                    ï¿½  the  need   to  consider   the   environmental,   urban  planning,    and
                       socioeconomic impacts of the safeguard projects from their inception;
                       and

                    ï¿½  the need to clearly evaluate the project's financial requirements and
                       to assign priorities.

                    In particular, we believe that it is not generally possible to rigidly
             maintain the "ante quo" situation.      Rather, when a sea level rise effect is
             forecast, it is necessary to develop a new environmental strategy, (1) with
             adequate human, urban planning, and aesthetic characteristics; (2) with limited
             social and cultural impacts; and (3) that is achievable with available financial
             resources.



             BIBLIOGRAPHY

             Carbognin, L., P. Gatto and F. Marabini. 1984. The City of the Lagoon of Venice
             - A Guidebook on the Environment and Land Subsidence. Venice.

                                                     158








                                                                               Sbavaglia, et al.


           Gormitz, V., S. Labedeff and J. Hansen.       1982.   Global sea level trend in the
           past century.    Science 215:1611-1614.

           Miozzi, E.    1960.   La Conservazione e la Difesa. dell'Edilizia di Venezia, il
           Minacciato suo Sprofondamento      ed i Mezzi per Salvarla.       Proceedings of the
           Conference  for "La Conservazione e Difesa della Laguna e della Citth di Venezia".

           Miozzi, E.   1968. Venezia nei Secoli, Vol. III: La Laguna.         Venice: Libeccio
           Publishers.

           Puppi, G.,  and A. Speranza. 1988. The physical problem of global climate on
           Earth. Alma Mater Studiorum 1:1-14.

           Titus, J.G., ed. 1988. Greenhouse Effect, Sea Level Rise and Coastal Wetlands.
           Washington, DC: U.S. Environmental Protection Agency.

           Titus, J.G.     1986.    Greenhouse effect, sea level rise, and coastal zone
           management. Coastal Zone Management Journal 14:3.






























                                                     159











                   IMPLICATIONS OF SEA LEVEL RISE FOR GREECE


                                       DR. HAMPIK MAROUKIAN
                                     Department of Geography
                                       University of Athens
                                           Athens, Greece





          INTRODUCTION

               Many parts of coastal Greece will be seriously affected by a rising sea
          level. If drastic measures are not taken soon by state and local governments,
          it will be much more difficult and more costly to face this problem later.

               Consider the delta of the Sperkhios River. If sea level rises 2 meters in
          the next century, this deltaic plain could lose about 40 square kilometers of
          land.   A rising sea level would also cause serious problems to coastal urban
          areas, industries, settlements, harbor facilities, tourist complexes, coastal
          communication networks, airports, and other infrastructure. The areas that will
          probably be most threatened are the big harbors of the country:                Pireas,
          Thessaloniki, Patra, Volos, Iraklio, Alexandroupoli, etc.        Many airports like
          Kerkyra, Alexandroupoli, and Thessaloniki are almost at sea level and will
          certainly be threatened.         Coastal highways in northern Peloponnessos,
          Thessaloniki plain, Sperkhios delta, Porto Lagos, etc., will have problems too
          (Figure 1).

               The incursion of the sea will create another very serious problem to the
          coastal environment, that of erosion. This process will most certainly affect
          densely populated coastal zones on low to intermediate slopes.             In recent
          decades, more than one million cottages have been constructed on or near the
          coastal zone.    Many of these already face erosion problems, since they were
          constructed without prior knowledge of the conditions that prevailed in the
          environment.    Thus, a sea level rise of just a few decimeters would be
          destructive to all these structures. Unfortunately, nothing has yet been done
          to put some limitations on coastal construction.

               Correspondingly, similar problems are expected to occur in coastal
          cultivated areas like the deltaic plain of the Sperkhios, the plain of
          Thessaloniki, the Argolis plain, Akheloos plain, and the Louros-Arakhthos plain.
          It is believed that parts of the extensive drainage and irrigation networks of
          these areas will be rendered useless.         The groundwater table will also be
          affected by rising seas. The underground saltwater wedge in the water table will
          certainly shift inland, affecting cultivated land.


                                                   161








                   Mediterranean


                                             220                           250                           280





                                                                      BULGARIA

                                  YUGOSLAVIA
                                                         N ............                          TURKEY
                                                                              ..................

                                                                              F
                                                                KAVALA
                                                                                  ALEXANDqOUPOLI
                                                        SALONIKI             PORTO
                                                        C*                   LAGOS


                                                  S



                    400                                                                                      .400


                        K RKY                       CZZ                G'
                                ARTA              VOLOSmA-

                                  F   S                  LAO-

                       AMVRAKI

                                      Q)
                                         OE                  AT.HIN
                                           PATRA
                                               KORINTH          I  S
                          0           S
                                                  NAFPL10                4
                                ZAKYNT


                                             KALAM
                                  %P       A

                                                                     S
                                                                                             K0


                                                                                                       ROD9,-,.l



                                                                      CRETAN        SEA


                                      LE GEN D
                    35c         9     Cities                                                                  350
                                a     Industries                    MEDITERRANEAN
                                A     Airports                                  SEA
                                W     Wetlands
                                F     Fisheries
                                S     So Itworks                                  0    5o    ioO 150 km
                                                  VOL@\












                                            220                           250                            280

                 Figure 1. Map of Greece.

                                                                162









                                                                                       Maroukian

                Finally, coastal wetlands will be covered by the rising sea level and an
           important natural resource of the environment of Greece will cease to exist. The
           lagoons of Messologi, Amvrakikos, and Porto Lagos, which are important fishing
           grounds, will become shallow bays or gulfs. The extensive saltworks of Messologi
           and other areas of Greece will have to move farther inland.

                Despite these problems, the prospect of sea level rise does not seem to
           concern officials from government or private   organizations in Greece. In recent
           meetings with high ranking officials of the Ministry of Environment, Physical
           Planning and Public Works (the main agency responsible for the management and
           protection of the Greek Coasts), they agreed that they would eventually need to
           take measures to confront the problem, but they felt that there is no urgency
           today.    They generally encouraged me to assess in more detail          the likely
           consequences of global warming and sea level rise, and to come back      and suggest
           to them options that could be rationally implemented today, given the
           uncertainties.

                This initial response made me realize that the most fundamental      barrier to
           responding to sea level rise in Greece will probably be similar to the barrier
           that has confronted the world in general since Svante Arhenius warned us of the
           greenhouse effect in 1896: the information gap between researchers and policy
           makers. This gap is more than a failure to communicate often enough: between our
           respective fields of scientific and policy expertise lies a conceptual "no man's
           land" into which both scientists and policy makers are reluctant to tread.

                As I left the meeting, my initial reaction was that the policymakers seem
           to unrealistically expect me to have all the answers on a "silver platter." But
           on the other hand, perhaps I was unrealistic to expect that if I presented them
           with scientific information on an environmental risk, they would be able to give
           me the response options on a silver platter.          Scientists feel comfortable
           describing observable facts, but are hesitant to speculate about future impacts
           of new phenomena, and are even less qualified to recommend policy actions. Yet
           by the same token, policy makers that feel comfortable making decisions when all
           the options have been laid out feel less qualified--and often lack the time--to
           develop planning and structural responses that have not been thoroughly assessed.
           To properly respond to sea level rise, scientists and policymakers must work
           together to answer questions that are interdisciplinary in the broadest sense of
           the word.

                But the necessary collaborative effort has not yet gotten under way in
           Greece, so it is not possible to provide a detailed examination of the impacts
           and responses to sea level rise.       The remainder of this paper describes the
           environment and the resources at risk.



           THE NATURAL ENVIRONMENT

           Climate and Tides

                The coastal climate of Greece can be characterized as Mediterranean with
           warm to hot dry summers and moist cool winters.           Storms are not a common
           phenomenon in Greece.    Storm winds usually blow from the northern or southern

                                                    163











              Mediterranean

              quadrants. Those from the east or west are rare and of short duration, no more
              than one or two days.

                   The tidal range around Greece, as in all of the Mediterranean Basin, is
              small. The greatest tidal range is observed at the Strait of Evripos where the
              northern and southern Evvoikos Gulfs join. The maximum tidal range is 1.20 m in
              the northern port of Khalkis and the mean is 0.42 m.

                   Although the Greek region has numerous earthquakes, tsunamis are rare.
              Nevertheless, it is very likely that the great explosion of the volcano of Thera
              (Santorini) around 3,400 years ago was followed by a catastrophic tsunami that
              reached all the shores of eastern Mediterranean Sea. According to Galanopoulos
              (1960), from 1801 to 1958 there occurred 170 earthquakes with a range fron I to
              VIII on the Mercalli-Sieberg scale, but only 6 tsunamis were destructive.

                   The low tidal range and absence of frequent storms implies that it has been
              safe to build one to two meters above sea level. As Titus (this volume, Problem
              Identification) points out, this situation potentially makes low areas more
              vulnerable to inundation than areas with frequent storms or large tidal ranges.

              Types of Coasts

                   Fortunately, Greece does not have a particularly flat coast, except for
              deltas.    About 31% of the coasts are rocky with slopes greater than 50%,
              generally along the northern portion of the western coasts of Greece, the
              northeastern coasts of the Gulf of Corinth, the western coasts of the Aegean, and
              some parts of Khalkidiki (Figure 2).        Another 25% of the coasts have slopes
              between 10% and 50%; these shores are often easily erodible, e.g., the southern
              Korinthiakos Gulf.

                   Despite the predominance of steep coasts, about 45% of the coast has slopes
              less than 10%. These include the deltaic plains of Arakhthos-Louros, Akheloos,
              Pinios (Peloponnessos), Sperkhios, Pinios (Thessalia), Aliakmon-Axios, Evros, and
              the fan delta of Nestos; the barrier beaches of northwestern Peloponnessos,
              Akheloos-Messologi, Amvrakikos, and Nestos; the lagoons of Messologi, Amvrakikos,
              and Vistonida; and all the pocket beaches, accretion beaches, and coastal plains.
              Figure 3 shows a number of low-lying areas in Greece.

                   The sediment size of most of the depositional features is in the sand range,
              but in many parts the presence of pebbles and stones is not uncommon. Although
              the presence of sand dunes is not rare in many parts of Greece, they are located
              along the coast without extending inland because of the short duration of the
              high intensity winds.

                   A final feature typical of warm seas is the presence of beachrocks. They
              all seem to be eroding today and are found mostly in the central and southern
              part of the country, usually in sandy' beaches. Most of them date from the Late
              Hol ocene age and are 1 ocated a coupl e of meters above or bel ow present sea 1 evel .



                                                        164











                                                                                                                                                               Naroukian




                                               20*                              2@-                                                                26-


                                                                                                                        Kavala              Alexandro.pol*

                                                                                               lbessaloniki







                                          40*





                                                                                           Volos





                                                                                                  STUDY AREA    Khalki

                                                                            Paux                              Pireas
                                        -38*






                                                                                  Kalarmats                               Gently sloping coasts

                                                                                                                          Intermediate coasts
                                           0      40      80      120     160lan                                          Steeply sloping coasts
                                                                                                                       o  Major parts




                    Figure 2. Distribution of slopes along the coasts of mainland Greece.


                             There are five major deltaic plains (Evros, Axios-Aliakmon, Sperkhios,
                    Akheloos, and Louros-Arakhthos) and four regions with barrier beaches, barrier
                    islands, and spits (Amvrakikos, Akheloos-Messologi, northwestern Peloponnessos,
                    and Nestos). There are also numerous pocket beaches, accretion beaches, and fan
                    deltas (the largest at Nestos).

                    Wetlands

                             The Ramsar Agreement, concluded in Iran in 1971, called for each country to
                    delineate the wetlands that were environmentally significant. For Greece these
                    are the following:

                                                                                                165





           A                               - ------          ------ - -- C


                                                              rM X* "41



















      C1   B


                                                                                  Figure 3 (A-C). Low-lying areas of Greece.
                                                                                  (A) Southwest Attica.   Eroding
                                                                                      coastline with newly built hotel in the
                                                                                      backgound.
                                                                                  (B) West Peloponnessos.   There is a road
                                                                                      sign in the middle of the picture but
                                                                                      the road is gone.
                                                                                  (C) Vulnerable church along the Porto Lagos
                                                                                      Lagoon in northeastern Greece.







          D



























      01
      @4
          E
                                                                                 Figure  3 (D-F)   Low-lying  areas of Greece.
                                                                                 (D)  Saltworks in Zakynthos  island, western
                                                                                      Greece.
                                                                                 (E)  Astakos, west-central Greece. Barrier
                                                                                      beach.
                                                                                 (F)  Amvrakikos Gulf, western Greece.
                                                                                      Barrier beach with lagoon on the
                                                                                      right.


                                @ 77
                                                  M" O"Id-,










              Mediterranean


              The Evros Delta Wetland

                   The River Evros is one of the largest rivers of the Balkan peninsula and is
              characterized by high discharge and sediment transport rates, particularly during
              the winter and spring months. There are four lagoons and at least three barrier
              islands of limited size.      Until 1950, human interference in the natural
              environment was minimal . Since then, various artificial drainage systems control
              to a large degree the flow of the river.

              The Vistonida-Porto Lagos Wetland

                   Lake Vistonida is located in central Thrace and is the extension of the bay
              of Porto Lagos.    It has an area of 4500 hectares (11,120 acres) and forms a
              shallow lagoon with an average depth of 2.0-2.5 meters and a maximum of 3.5
              meters. The average height of Vistonida is 0.10 meter. The deterioration of the
              surrounding lowlands has led to their increased erosion and sedimentation
              deposition in the lake, which has resulted in a rise of the lake bottom by 0.40
              meter from 1976 to 1982.

              The Nestos Delta Wetland

                   The Nestos River is the natural boundary between Macedonia and Thrace. Its
              source is in Bulgaria and its length in Greece is 130 km. The main wetland area
              comprises the main channel, the bank zones, and the coastal zone of lagoons (Nea
              Karvali-Nestos mouth - Cape Baloustra). The general area of the coastal zone (a
              length of about 45 km and width of 1.5-3 km together with the Nestos Delta) is
              characterized by a great variety of biotopes with various plant colonies and
              zones of vegetation.    The present cultivation of the land has worsened the
              conditions in the Nestos wetland.

              The Aliakmon-Loudias-Axios Delta Wetland

                   This region covers the lower deltaic plain of three rivers (Aliakmon,
              Loudias, and Axios) and has an area of about 200 square kilometers. The largest
              part has been apportioned to the local peasants.       The coastal parts of the
              deltaic plain are drained today for cultivation purposes. This process, together
              with water and soil pollution, has turned this wetland into a very unstable and
              endangered environment.

              The Messologi Lagoon Wetland

                   This wetland is found in the middle of western Greece next to the Akheloos
              Delta. It is composed of three lagoons (Aetoliko, Messologi, and Klisova) and
              has a total area of 25,800 hectares (63,752 acres).      The natural biotope has
              deteriorated in the last twenty years owing to the draining of some areas and the
              conversion of others to salt-works.

              The Armvrrakikos Wetland

                 I Found in northwestern Greece, the wetland forms a closed sea with a total
              shoreline length of 256 km and a maximum depth of 60 m. The Louros and Arakhthos

                                                     168










                                                                                       Maroukian

            Rivers flow into the gulf where the Logarou, Tsoukalio, Rodia, and Mazoma Lagoons
            are I ocated as wel 1 as the Bay of Koprani . The wetl and i s burdened by human and
            industrial effluents as well as agricultural and cattle by-products.

            The Lake Koukhi Wetland

                 This wetland is located in northwestern Peloponnessos facing the Ionian Sea.
            It connects to the sea through a very narrow inlet having a width of only 8 M.
            The deepest part of the lake is 40 cm and the mean is 30 cm. Its area varies
            seasonally from 710 hectares (1,754 acres) to 850 hectares (2,100 acres). It is
            one of the largest lagoons in Peloponnessos. It is rapidly deteriorating, mainly
            as a result of human activities (agriculture, hunting, and pollution).

                 Because of the low tidal ranges in Greece, these wetlands are barely above
            sea level and hence would be mostly lost with a one-meter rise in sea level.


            SOCIOECONOMIC FEATURES

            Demography

                 A large part-of the Greek population has lived near the coast since ancient
            times.  Many ancient city-states flourished along the Greek coast and in many
            cases their very existence depended on their coastal colonies in the
            Mediterranean Basin. The population of ancient Athens, for example, could have
            been a few hundred thousand people. In Roman and Byzantine times and the ensuing
            period of Turkish occupation between the fifteenth and nineteenth centuries, life
            deteriorated and inhabitation in coastal areas decreased considerably. In the
            early nineteenth century, Athens was just a village of 5-6,000 people. Today,
            greater Athens has about 3.5 million inhabitants.

                 Table 1 gives a general picture of the proportion of inhabitants on or near
            the coast of mainland Greece.     This number is 52% of the total population of
            7,083,000 living in the above-mentioned departments. If we consider the seasonal
            migration of the Greek population toward the coasts in summer, then this
            percentage could easily reach the 65% mark.       Furthermore, if we include the
            millions of tourists who visit Greece during the summer months, then it is safe
            to say that for a considerable time of the year, about three quarters of the
            population live along the coasts.

            Harbors, Ports, and Other Coastal Structures

                  Various types of artificial structures are found along the coasts of
            Greece. They may be classified into three main groups:

                  1.     harbor and other ship-related structures,
                  2.     coastal defense structures, and
                  3.     water intake/outfall structures.




                                                    169









              Mediterranean

             Table 1.     Number of Inhabitants Who Lived On or Near the Coast of Mainland
                          Greece (by department in 1981)


                              Department                            Population (x 1,000)


                            Aetoloakarnania                                    99
                            Argolis                                            49
                            Arkadia                                             9
                            Arta                                               28
                            Attiki                                           1,947
                            Akhaia                                            190
                            Evros                                              48
                            Evvia                                             116
                            Ilia                                               71
                            Imathia                                             3
                            Thesprotia                                          1
                            Thessaloniki                                      597
                            Kavala                                             83
                            Korinthia                                          60
                            Lakonia                                            21
                            Larissa                                            11
                            Magnissia                                         135
                            Messinia                                           72
                            Xanthi                                              5
                            Pieria                                             29
                            Preveza                                            25
                            Rodopi                                              3
                            Fthiotida                                          63
                            Fokis                                               9
                            Khalkidiki                                         23
                            TOTAL (includes rounding)                       T,-697



                  Greece has a total of 444 commercial harbors of various sizes and
             importance, of which 284 have sea defense structures (these numbers do not
             include small harbors for local ferries). The first group of structures is by
             far the most important.      It includes, among other types, such structures as
             moles, breakwaters, bulkheads, jetties, and trestles. Moles and breakwaters have
             either vertical or sloping faces. The most commonly used materials are quarry
             stones and concrete.   In many cases, especially in the smaller harbors, jetties
             serve several purposes including those served by moles and quays.           The most
             common type of quay walls are gravity walls of concrete blocks.         Jetties are
             usually formed with a surrounding bulkhead and backfilling.

                  Coastal defense measures usually consist of revetments, groins, and, more
             recently, artificial nourishment. Coastal revetments and groins are built almost
             exclusively with quarry and concrete blocks.


                                                      170










                                                                                   Maroukian

               In Table 2, the most important harbor installations are shown together with
          passenger and cargo movement.

               Pireas shows the greatest domestic movement of passengers and cargo, most
          of it being car-ferries (ferry boats). Pireas together with Rafina serve to a
          great extent the Aegean islands. The high cargo movement of Thessaloniki is due
          to the transport of goods to neighboring countries (Yugoslavia and Bulgaria).
          The increased cargo movementin Volos is due to the transport of goods from Europe
          to the Middle East (Syria). The high number of passengers arriving in Patra and
          Igoumenitsa is due to the increased arrivals of tourists from Italy with car-
          ferries during the summer months.

          Land Use

               A large proportion of the Greek coast with steep slopes and cliffs has not
          been developed.   The remainder is composed of deltaic plains, narrow coastal
          plains, and pocket beaches. In many cases, these coastal zones were developed
          in a very disorderly fashion before the state could intervene. As a result of
          this anarchic development, construction in the coastal zone has, in many
          instances, upset the equilibrium that exists in the coastal environment.

               In several coastal lowland areas, particularly in the Messologi region,
          there are extensive salt works. In other parts of Greece, like the plains of
          Thessaloniki, Sperkhios, Amvrakikos, Evros, and southern Peloponnessos, there are
          large areas with rice fields. In the Argolida-Messinia-Lakonia area, northern
          Peloponnessos, Volos, and Crete, there is extensive cultivation of fruit-bearing
          trees and horticulture. Olive trees are found everywhere in       Greece, but the
          main producing areas are in Amfissa-Itea, western and southern Peloponnessos
          (Kalamata), and Crete.

                The often thoughtless exploitation of water resources in coastal areas with
          water pumps and wells has led to a serious drop of underground water tables and
          simultaneous advance of saltwater.       This has led to the degradation of
          underground waters which, in turn, has affected the quality and quantity of
          agriculture in the coastal zone.    This problem will only be exacerbated with
          rising sea level and more frequent droughts resulting from global warming.

          Fisheries

                Aquaculture is a very important activity in Greece. The indented coastline
          and its great length complement aquaculture development.      Important areas of
          coastal fisheries are the lagoons of Messologi, Amvrakikos gulf, and Porto Lagos.
          Fishing boats are usually of small displacement and the production is intended
          for domestic consumption (Table 3). Exports are minimal.

                In recent years, a great effort has been directed to the reorganization and
          modernization of fisheries in the various lagoons of Greece to make them
          profitable, in both quality and quantity.




                                                 171









               Mediterranean

               Table 2. Number of Arriving Boats, Passenger and Cargo Movement in Selected
                          Harbors of Greece (1986)

                                                     Passengers                       Cargo
                                  Arrivals    Embarking      Disem-             Loaded    Unloaded
                                      of        (1000s)     barking           (10' tons) (10" tons)
                  Harbor          vessels                   (1000s)


               Pireas             17,600        2,701       2,664             2,125         4,825
               Thessaloniki        2,400           11          10             2,452         8,024
               Patra               2,250          492         584               219          349
               Iraklio             2,030          382         385               428         1,313
               Rodos               1,980          128         124               213          394
               Kerkyra             2,180          114         147                19          165
               Alexandroupolis        830          44          42               335          115
               Kavala                 880          15          16             1,662          645
               Volos               3,330          107         105             3,714         2,837
               Kalamata               200                                        16          156
               Igoumenitsa         2,080           86         108                  3         254
               Khania (Souda)         200         180         182               141          318
               Khalkis                800                                     1,635          818
               Syros               2,100          110         110                37          103
               Rafina              1,700          330         328                77            81

               TOTAL              140,000       9,256       9,297             38,703       46,203



                          Table 3. Fishing Vessels    and Fish Caught in Greece (1986)


                                              Total     Coastal Fisheries          %


               Number of fishing              6,380            5,500               89.7
                 vessels

               Fish caught (tons)           112,700           35,700               31.7



                    Fishing could be vulnerable to   sea level rise both because the fishing ports
               and other activities are located in low areas, and because the loss of wetlands
               would reduce fish populations.

               Coastal Development

                    Human intervention in the deltaic plains, the lagoons, and the wetlands is
               not very extensive. Shore alignment and protection structures are found in some
               lagoons like those of Amvrakikos, Messologi, and Porto Lagos (Vistonida).

                                                        172










                                                                                    Maroukian

           Important shore protection structures (against erosion) are found only in the
           area of Messologi and the deltaic plain of Thessaloniki.

                The state has spent very little on the development and protection of the
           coastal environment. Beside harbor works in various locations of Greece and the
           construction of some coastal - roads, state assistance that addresses coastal
           problems is of only local significance.

                Private investment in the coastal region, however, is at high levels. In
           the last decades, thousands of summer cottages have been constructed in many
           parts of the Greek coasts.     This rapid settlement development is frequently
           accomplished without any planning and is many times done illegally.        Another
           important development along the Greek shores is the construction of big vacation
           complexes with hotels and all kinds of sports and recreational facilities.

                Finally, a variety of industrial complexes, like oil refineries, aluminum
           smelters, steel works, shipyards, and dockyards, are located in coastal zones.
           All of these activities will be vulnerable to a rise in sea level unless some
           remedial actions are taken.



           CONCLUSION: THE NEED FOR A GOVERNMENT POLICY

                The first attempt at a comprehensive solution to the question of coastal
           management and protection was made with Law 2344/1940.       There followed many
           amendments and additions, mostly relating to land use and management of the
           coastal zone.

                Following the increasing interest in the protection of the environment in
           recent decades, a national coastal management program was started in 1980. The
           implementation of this program was entrusted to the Ministry of Physical Planning
           and Environment. The primary aims were as follows:

                1.  To prepare a uniform and complete program for the development and
                    management of the coastal zone; and

                2.  To study the following:

                    0   Settlement patterns and deterioration of the coastal zones;
                    0   The frequent irreversible destruction of the natural ecosystems and
                        landscapes;
                    0   The reduction of productive agricultural land;
                    0   The   exhaustion  of marine     resources  due   to  pollution    and
                        overexploitation; and
                    0   The inaccessibility of the beach due to continuous land ownership
                        along the beach.

                Unfortunately, this program never had the financial resources necessary to
           carry out its original mandate.       Recent administrations have shown little
           interest in spending additional money on the project, and there has not been a
           large outcry from the public to revive this initiative. Nevertheless, the wave

                                                  173









             Mediterranean

             of concern for the environment sweeping across- 'Europe is beginning to be felt in
             Greece, and the protection of our coastal heritage is an obvious priority.

                  Clearly, any new national research, planning, or management efforts to
             protect the coastallenvironment should estimate the likely impacts of sea level
             rise; calculate the costs of alternative response strategies such as retreat and
             holding back the sea; and compare costs for alternative policy implementation
             dates between today and 2020, particularly in the case of land-use restrictions.
             Such an assessment will require a technical panel- including coastal geologists,
             engineers, planners, economists, and public works.officials.

                  In the narrow sense, we can afford to ignore, accelerated sea level rise for
             a while, because the consequences are a few decades away, and a culture that has
             survived as long as ours is hardly'likely to perish at the hands of a changing
             climate. But, by the same token, since we know that there will be a Greece for
             centuries to come, is it proper to ignore the adverse impacts that our actions
             today may bequeath to future generations?          Compared with the potential
             env i ronmental , cul tural , and economi c 1 osses that coul d resul t from a ri se i n sea
             level, the cost of developing a national response strategy would be small.































                                                    174









                                                                                     Naroukian

                     APPENDIX: DETAILS OF COASTAL CLIMATOLOGY, CURRENTS, TIDES,
                                        AND TSUNAMIS IN GREECE



           PRECIPITATION

                The general characteristic of the geographical distribution of mean monthly
           temperatures is a decrease with higher latitudes. July and August are exceptions
           because they present great temperature homogeneity.        Generally, the western
           coasts of Greece are a little warmer than the eastern coasts during the winter
           months. The opposite is true during the summer months. Both the temperature
           difference and the summer duration increase with higher latitudes. The eastern
           coasts experience a more continental climate.

                The precipitation system that prevails all over Greece is of the
           Mediterranean type and is characterized by winter precipitation and summer
           drought (Table A-1). During the warm period of the year, rainfall increases from
           south to north because of the increasing continentality of the climate. The mean
           annual precipitation is 706.8 mm.


                   Table A-1. Mean Monthly Precipitation in Greece (mm)


                       Month         Amount               Month   Amount



                         1            112.5                 1       12.4
                         F            80.9                  A       10.4
                         M            70.4                  S       29.8
                         A            41.5                  0       77.4
                         M            33.9                  N       92.8
                         1            21.4                  D       123.4



                The maximum 24-hour   period precipitation occurs during autumn and winter
           months and rarely during  the remaining months of the year, e.g., Lefkas 248.0 mm
           in November, and Rodos    320 mm in January.     The largest number of     days of
           precipitation are observed during the month of January.

                The greatest snowfall occurs in January and February, followed by December
           and March. The mean number of days with snow increases with increasing latitude,
           distance from the sea, and from west to east.

                When a low-pressure storm arrives from the west, the weather over Greece
           becomes cloudy with a tendency toward rain and storms over the Aegean Sea while
           wind intensity abates. Finally, storms from the south occur when a low pressure
           from the west passes over the Balkan Peninsula, north of the Aegean Sea.



                                                   175









              Mediterranean

              WINDS

                   In general, the most prevalent winds blow from the northern quadrant. The
              highest wind speeds occur in the open seas, mostly in the central Aegean Sea, in
              the Ionian sea, and between Crete and Peloponnessos. In the summer, the Etesian
              winds blow from the north.

                   The direction, intensity, and duration of the winds, along with the fetch
              length, determines the height of waves. The general circulation of winds in the
              Greek seas depends on the distribution of the atmospheric pressure, which is
              affected to a great extent by the local influences of the distribution of the
              seas and the uneven setting of the mountain masses.

                   In winter, we have northerly winds, which are the result of high-pressure
              cells covering the Balkans and northern Russia. These winds become very intense
              if a storm occurs over Greece when cyclonic depressions move over or move north
              of the Greek seas. This results in very intense southerly winds.

                   In summer, the prevailing winds over the Greek seas are northerlies, called
              Etesian. They are seasonally very constant, being northernly and northeasternly
              in the Aegean and northwesternly in the Ionian and western Greece.           Their
              dominance is interrupted in fall when southerly winds start becoming more and
              more frequent, thus keeping coastal temperatures high long after summer is over.

                   The temperature of the surface of the Greek seas presents a normal annual
              fluctuation with a minimum in February and a maximum in August (Figure A-1) . The
              annual temperature range of the surface water fluctuates between 9.8*C in the
              south Aegean Sea and 11.5*C in the north Aegean Sea. The warmest seas of Greece
              are found in the north Aegean and the Ionian Seas all year round.

                   According to observations by the Hydrographic Service of Greece, the highest
              mean annual sea surface temperature is located around Rodos (19.70C) and the
              lowest near Alexandroupolis (15.50C).


              CURRENTS

                   The currents in Greece are of three types:

                   * Local currents,
                   * Tidal currents, and
                   0 General currents of the open sea.

                   Local currents are directly dependent on the configuration of coasts, depth,
              the bottom relief, and the direction and intensity of winds.
                   The main tidal currents occur at the Strait of Evripos, the Corinth Canal,
              the Strait of Lefkas, at the entrance of Amvrakikos gulf, and at Rio-Antirio
              Narrows.




                                                    176









                                                                                                                      Maroukian






                                January                           February                        March


                                                                       13                               1
                                             14                     4


                                                                                                            15

                                          16


                                April           13               May                              June         20

                                     14

                                                                    7
                                                    5

                                             15                              8                                  21




                               July             2               August         24                September      2
                                                                        A2
                                                2
                                                                                                   3

                                                                              23

                                                                                      4                4
                                  24

                                                     24                           25


                                October                          November             1-1        December       3

                                                                                                 6


                                                                                                                    5








                                    23
                                      r
                                                               @
                                                                     r uary                    A15
                                                                       13
                                                                    4    M
                                                                                               @ne      205
                                                                                                                21










                                                2
                                     K2

                                                                                                                    5
                                                                                                                    15
                                                                                                                    1
                            23%



                Figure A-1. Mean monthly sea surface temperatures (OC) of the Greek seas.

                                                                         177









              Mediterranean

                   The open sea currents generally follow an east-west direction. The current
              originating from the Black Sea determines the motion of the north Aegean currents
              giving a general east-west direction and a north-south direction in the western
              Aegean. The Black Sea current, as it comes out of the Dardanelles, has a speed
              of up to 2.5 knots and Is directed to the south.

                   In the central Aegean, there is an anticlockwise motion, while in the
              southern Aegean there is a clockwise movement around the island of Crete. Along
              the east Aegean, there is a south to north current.           In the Ionian sea, the
              general motion of the currents is from south to north except near Kerkyra (Corfu)
              and Lefkas, where the current near the coast runs from north to south.


              TIDES

                   Most stations use automatic tide gauges, and the remainder use tide poles
              (Table A-2).


                                      Table A-2. Tide Stations in     Greece


               1.  Aedipsos                12.   Kavala*              23.   Posidonia*
               2.  Alexandroupolis         13.   Kalamata*            24.  .Preveza*
               3.  Aliverion               14.   Katakolon            25.   Rodos
               4.  Amfiali                 15.   Kerkyra              26.   Skiathos
               5.  Argostolion             16.   Leros                27.   Souda (Khania)*
               6.  Volos                   17.   Lefkas*              28.   Stylis
               7.  Gythion                 18.   Limnos               29.   Syros*
               8.  Igoumensitsa            19.   Mytilini             30.   Khalkis (north)*
               9.  Iraklion*               20.   Salamis              31.   Khalkis (south)*
              10.  Thessaloniki*           21.   Patra'               32.   Khios*
              11.  Isthmia                 22.   Pireefs*

              Note:   Stations with a cross use automatic tide        gauges; all others use tide
              poles. Stations 4 and 11 have been discontinued. Source: Zoi-Morou (1981).


                   During their installation, the leveling of the stations is linked to the
              national geodetic system of the country by the Greek Army Geographical Service.
              It is possible to divide the Greek seas into three large areas (Table A-3).

                   1. The north Aegean Sea with tidal ranges between 0.11 and 0.25 m;
                   2. The south Aegean Sea with tidal ranges between 0.05 and 0.08 m; and
                   3. The Ionian Sea with tidal ranges between 0.05 and 0.18 m.


              TSUNAMIS

                   Tsunamis in Greece are rare.        Their zones of origin coincide with the
              seismogenic zones of the external island arc of the Greek microplate (Ionian

                                                        178









                                                                                      Haroukian

           islands, Crete, Rodos) as well as with the internal volcanic arc (Corinth -Megara,
           Aegina, Milos, Santorini, Nisyros, Kos).

                Along these zones there occur numerous earthquakes which every few years
           reach an intensity of >_6 on the Richter scale. Owing to the highly irregular sea
           bottom terrain, there is a possibility of submarine landslides which can
           sometimes produce tsunamis.

                The tsunamis have not been systematically studied in Greece.         The first
           study was done in 1956 by seismologist Galanopoulos when a tsunami-like
           phenomenon occurred in the southeastern Cyclades, following a great earthquake
           on July 9,  1956 (36.94, 26'E, H = 03:11:38, M = 7.5).        The tsunami owed its
           genesis to a submarine landslide on the steep slopes of the southeastern shores


           Table A-3. Maximum, Mean, and Minimum Tidal Ranges (in Meters) at Tide Stations
                        in the Ionian and Aegean Seas


           Station                Maximum Range       Mean Range       Minimum Range


           Ionian Sea
           Preveza                      0.28             0.05               0.01
           Lefkas                       0.30             0.11               0.01
           Katakolo                     0.67             0.08               0.01
           Patra                        1.05             0.18               0.01
           Kalamata                     0.58             0.11               0.01

           South Aegean
           Syros                        0.32             0.05               0.01
           Khania (Souda)               0.25             0.06               0.01
           Iraklio                      0.58             0.08               0.01
           Leros                        0.52             0.06               0.01

           North Aegean
           Thessaloniki                 0.94             0.20               0.01
           Kavala                       0.96             0.25               0.01
           Alexandroupolis              0.65             0.13               0.01
           Limnos                       0.60             0.11               0.01

           Source: Zoi-Morou (1981).


           of Amorgos Island (36.80N, 26.20E). The seismic sea wave caused sea level to
           fall up to 3 meters and rise 2.5 meters. The wave train affected almost all the
           harbors of the south Aegean. Galanopoulos prepared a map with the sources of
           known tsunamis which proved to be destructive in historical times (Figure A-2).

                 A second tsunami was generated by an earth slump, set in motion without
           shock, in the area of Aegion in northwestern Peloponnessos when a massive

                                                    179









                           Mediterranean

                           slumping, estimated to have a mass of 57,000 cubic meters, subsided 5-44 meters
                           below the sea level and the coastline in some parts receded up to 500 meters
                           inland (Comninakis et al., 1964). Even though there was no earthquake at the
                           moment, the slump occurred (7 February 1963), it was preceded by seven local
                           earthquakes west of Aegion on 2 February 1963.





                                               20.          21-        22'         23-         24*         23*         20*          271        26*          2r
                                                                        I
                                                                       MACEDONIA
                                         41'                                                                       M3


                                                                                        -799C


                                         40.. ''                                     j                /     0


                                              1an


                                                                              426            00
                                                               CFNTRAL
                                                                   4zb 551 A.                                                                                  3a,
                                                                                     1W7                                         389.



                                         3W
                                                                             1817            @7,
                                                                             loot
                                                              tilt1                                                                                          -37-
                                                                to   f

                                                                        W4
                                         37-
                                                            -9@
                                                                                                                                                               30.
                                                                                              THERA 1.

                                                 Earthquakes accomoon4d
                                                          by Tsunamis
                                                     Of a herr"le" Nature                                                                                      3W
                                                     fairly Gestructive                                       CRE      E
                                                       a 20
                                                       'e,                                   30         -

                                                                                          23*         24-            23-          28*          2r            201




                           Figure A-2. Sources                  'of tsunamis that have affected                         the coasts of Greece from 479
                           B.C. to A.D. 1956.




                           BIBLIOGRAPHY

                           Comninakis, P., N. Delibasis, and A. Galanopoulos. 1964. A tsumami generated
                           by an earth slump set in motion without shock.                                              Annales Geologiques des pays
                           Helleniques          16: 93-110 (in Greek).

                                                                                                 180










                                                                                           Maroukian

            Dagre, D., and Lambrou, D. 1981. Study of the legislation about "aegialos" and
            "paralia." Athens: Technical Chamber of Commerce, (in Greek).

            Galanopoulos, A.G.      1957.   The Seismic sea wave of July 9, 1956.            Praktika
            Akadimias Athinon 32: 90-101 (in Greek).

            Galanopoulos, A.G.      1960.    Tsunamis observed on the coasts of Greece from
            Antiquity to   present time. Annali di Geofisica, 13 (3-4): 369-386.

            Hydrographic   Service. PILOT (Ploigos), Athens (in Greek).
                   Volume  A.  Western coasts of Greece 1971, with announcements in. 1983 and
                                      1986.
                   Volume  B.  Southern coasts of Greece 1976.
                   Volume  C.  Northeastern coasts of Greece 1947, with announcements in 1983
                               and 1987.
                   Volume  D.  Northern and eastern coasts of Greece, 1987.

            Kamkhis, M.   1981. The development and protection of the coastal zone in Greece.
            Proceedings of the Conference on the Development (Growth) of Greece, Athens, III.
            pp. 152-156.

            Kotini-Zabaka.     1983.   Contribution to the Study of the Climate of Greece by
            month. Doctoral dissertation. Thessaloniki, Greece: University of Thessaloniki
            (in Greek).

            Maroukian, H. 1989. Sea level in the past, present and future. Proceedings of
            the First Panhellenic Geographical Conference, 2, 1987, Athens.

            Ministry of the Environment, Physical Planning, and Public Works. Program for
            the delineation of wetlands of the RAMSAR agreement. 1986. Athens: Ministry
            of the Environment, Physical Planning, and Public Works (in Greek).

                      i.  Evros delta
                     ii.  Lake Mitrikou
                   iii.   Lake Vistonida-Porto Lagos
                     iv.  Axios-Loudias-Aliakmon delta
                      v.  Nestos delta
                     vi.  Kotyhi lagoon
                   vii.   Messologi lagoon
                viii.     Amvrakikos gulf

            Moutzouris,   C., and Maroukian, H. 1988. Greece. In: Artificial Structures and
            Shorelines. H.J. Walker ed. New York: Academic Publishers, pp. 207-215.

            National Statistical Service of Greece.         1982.    Actual population of Greece
            according to the April 5, 1981 census, Athens: National Statistical Service of
            Greece (in Greek and French).

            Zoi-Morou, A. 1981. Tide data of Greek harbors. Oceanographic Study no. 13,
            Athens: Hydrographic Service (in Greek).


                                                       181











                        IMPACTS OF SEA LEVEL RISE ON TURKEY



                                       PROF. DR. OGUZ EROL
                         Institute of Marine Sciences and Geography
                                University of Istanbul, Turkey






          ABSTRACT

               The low coastal belt of Turkey is occupied by intensive agricultural land
          use, and most of the cities, towns, and villages are found along the lowland
          coasts. But most of the population is settled on the high cliff sections of the
          coast. The ports are principally established at a point where the stretches of
          sedimentary coastline meet the relatively higher bedrock ground. Some parts of
          the harbor cities and industrial establishments have extended onto the low
          coastal plains, especially during recent years. Because they are not wide areas,
          these parts may be subject to disruption as sea level rises. Artificial coastal
          protection is not present along this low coastline because there is mainly no
          need for it at present.

               The common assumption in Turkey that sea level is constant is not shared
          by the scientists, and for good reason.      The Turkish shores have fluctuated
          several times during the Holocene, and sea level has been rising at least for
          the past 4,000 years.      But because the rising sea has been balanced by
          sedimentation and tectonic uplift, for most practical purposes it has been
          reasonable to assume that sea level is constant. But if global warming is likely
          to cause a 50- to 100-cm rise in the next century, the time is now to recognize
          this issue in the coastal decisionmaking process.     In Turkey, some government
          offices are responsible for planning and construction of harbors and other
          coastal establishments.      Some municipalities of coastal cities are also
          responsible for managing low coastal plains, but none of them is yet dealing with
          a future sea level rise.    Will it take a dramatic event to draw the attention
          of policymakers, or can they respond to scientific information?


          INTRODUCTION

               When one asks "What will happen on the Turkish coastline if the sea level
          rises?", the answer at first seems simple:      not much, because the Anatolian
          Peninsula is a tectonically uprising block, and, except in the deltaic areas,
          there are no extensive lowland areas around it.          But if sea level rise
          accelerates, the hidden dangers will emerge. Because tides and storms are small,


                                                 183











             Mediterranean

             many coastal establishments and settlements have been built within 2 meters of
             sea level and will eventually be inundated unless dikes are built.        But many
             fishing villages, such as Meset Limani illustrated in Figure 1, could not afford
             dikes, and an inland migration would not be feasible if traditional activities
             were to continue.

                  In the past, the main causes of shoreline changes have been sea level
             fluctuations due to tectonic uplift and subsidence, alluviation, and human
             activities (Erol, 1983, 1988). The most important recent changes have been in
             deltas (Erol, 1983; Bird, 1985), which in some cases have advanced 40 kilometers
             seaward (Erol, 1976).     Because of changes in river courses, Ephesus, Priene
             Miletus,   Kaunos,   and many other ancient harbors        have been abandAed.
             Nevertheless, tectonic uplift -- often associated with earthquakes,-,,has also
             been important in some cases. For example, the city of Seleukeia Pieria' in Hatay
             was completely abandoned after Byzantine times (Erol, 1963; Pirazzoli et al.,
             1989).

                  No one has assessed the impacts of a 50- to 200-cm rise in sea level.
             Nevertheless, a number of expectations seem reasonable. First, in the high rocky
             cliff coasts, the rising sea level will not cause great changes or shifts of the
             coastline, but the rate of cliff recession will accelerate, increasing the
             frequency and extent of landslides and destroying portions of many coastal roads.
             Second, along low, eroding, soil cliffs, there may not be immediate changes, but
             erosion will eventually result.       Because these areas are already densely
             populated narrow terrace strips, displacement of destroyed coastal establishments
             will become a serious problem, and protecting them from the sea will cause
             erosion elsewhere.    Finally, along deltaic coasts that are advancing seaward
             today, rising sea level will reverse the shoreline change, and coasts will begin
             to retreat. The geomorphological result of this will be a thick alluviation that
             may bury relatively new deltaic soils and perhaps interrupt agricultural activity
             on the deltaic plain as much as droughts do today.

                  Many coastal establishments would be displaced as a result of these changes.
             In the high rock cliff areas, the increased activity will influence the
             settlement points, roads, etc.    Since the places at the top of the cliffs are
             already scarce, rebuilding settlements elsewhere will be difficult if not
             impossible.     In the narrow strip of low soil-cliff terrace areas, the
             displacement of ruined coastal establishments, especially tourist places, will
             be several times more expensive.     In the low deltaic areas, which are already
             overcrowded, displacing the populations may be politically impossible,
             necessitating expensive coastal protection. Even where it is feasible, it will
             encroach upon important agricultural areas, which is already happening due to
             population growth. In Turkey, the art of life may have to change.

                  Many cultural sites would also be at risk. Besides the modern settlements,
             most of the ancient harbors and cities would be covered by seawater. Because
             of sedimentation, they would be buried, and access to these ruins would be much
             more difficult.   Some of them would be destroyed by increased wave activity.
             Because of their great number, moving the ruins would be practically impossible,
             and in any event, it would change their character.

                                                     184











                                                                                                Ero 7

















                                                          MOO


                                                                 Now




                                            4




           Figure 1. A   typical   Turkish fishing   town.   While towns like this clearly lack
           the resources to hold back the sea, retreat is not a viable option either.


                In Turkey, the State general directorates and offices responsible for
           planning and constructing airports and harbors are connected to the Ministry of
           Construction and Settlements.       In addition to these General Directorates, the
           State Planning Department and some municipalities of the coastal cities have
           interests in the low coastal belt of Turkey.

                None of these agenci es i s deal i ng yet wi th the i ssues and probl ems that wi 11
           accompany future sea level rise. When asked about the problem, they generally
           minimize its significance.         Even coastal engineers, who would seem more
           predisposed to incorporate technical information, are designing coastal
           establishments without regard for future changes.

                In the Turkish law for coastal protection, sea level is accepted as an
           "unchanging" boundary between the land and sea.           Even without the greenhouse
           effect, we know that such a definition is technically inaccurate, but in the past
           it has not mattered as other processes offset rising sea level.              But in the
           future, keeping this definition in our coastal policy will yield irrational
           results, as the United States and other countries with higher current rates of
           relative sea level rise have already seen (Titus et al., 1985).

                The remainder of this paper summarizes the natural environment of Turkey
           and human activities along its coasts.


                                                      185











              Mediterranean


              THE NATURAL ENVIRONMENT OF TURKEY

              Climate and Waves

                   Turkey 1 i es between the mi ddl e I at i tudes and the Med i terranean macrocl i mat i c
              zones and has a transitional character. The climate of the Black Sea is mainly
              under the influence of northerly winds that usually blow as gales. Because of
              the long fetch of the Black Sea and the absence of intervening islands, large
              waves strike the shore; hence high coastal cliffs and shingle beaches at the
              mouths of short mountain rivers are eroding. Details of wave heights and water
              temperatures are in Appendix 1.

              Coastal Geomorphology

                   The coast of Turkey has developed under the influence of (1) the
              geomorphology of the mainland -- that is of the Anatolian Peninsula and
              especially of the North Anatolian and Taurus folded mountain chains and the belt
              of faulted central plateaus; and (2) the submarine relief of the sea basins
              surrounding the peninsula. The coastline of Turkey may be divided into three
              main groups: (1) retreating cliffed coastlines on rocky and soil material (5,752
              km), (2) advancing sandy depositional soil (1,546 km), and.(3) advancing, partly
              swampy deltaic soils (1,035 km).

              High Rocky Cliff Coastlines

                   High rocky cliffs are found mainly on the north and south Anatolian
              coastlines, which run parallel to the folded mountain chains.        There are,
              however, some shorter stretches of similar coastline on the faultline coasts of
              the Aegean and Marmara Seas. This type of high rocky cliff rises sometimes a
              hundred meters above the sea. These cliffs are interrupted by river mouths with
              limited shingle beaches on the north and south Anatolian coastlines.      On the
              Aegean coastline, on the other hand, the rocky cliff coasts of fault mountains
              are relatively short and are interrupted by several deltas.

                   Generally, the high rocky cliff coasts are slowly eroding. At the foot of
              the cliffs, the coastal platform is usually very narrow or absent. Therefore,
              building highways along the coastline is extremely difficult, and the roads are
              located on the top of the cliffs if possible.     Because of the humid climate
              during all seasons of the year, landslides are common on ' the Black Sea coastal
              strip. However, because of the minor drop in sea level following the Climatic
              Optimum of the middle Holocene, narrow sandy beaches have developed at the foot
              of these cliffs. In the event of a future sea level rise, these narrow sandy
              beaches will be covered by water again, exposing cliffs to waves, which will
              accelerate their erosion.

              The Low Soil Cliff Coastlines

                   Low (2-meter elevation) and medium-high (10- to 20-meter elevation) cliffs
              composed of soft sediment are found at the base of many Pleistocene terraces.
              For the most part, the coastal belt is a narrow strip between the sea and the

                                                     186











                                                                                        Ero I

           mountains. Because these coastal belts have been ideal for settlement, tourist
           and industrial establishments, and road construction, they are densely populated.
           Although this narrow strip has a few meters of relief, the increasing exposure
           to waves will cause erosion, and shorefront establishments will be ruined at an
           increasing rate.

           The Low Unconsolidated Coastlines

                These low stretches are found especially on the deltaic coastlines. They
           include wide sandy beaches, beach rock, lagoons, tidal flats, and coastal dunes.
           Because rivers are supplying large amounts of sediment, these shores are
           advancing into the sea today. Accelerated sea level rise, however, would reverse
           this process.

                Especially on the north and south Anatolian coastline, the small deltaic
           unconsolidated coastlines consist mainly of gravel and shingle beaches. This
           is the result of the influence of the strong waves and coastal currents.
           Although there are no barrier islands in Turkey, some coastal spits have
           developed at the mouths of rivers and bays; some have formed along the foots of
           cliffed coasts.    These low areas are very vulnerable to both inundation and
           erosion due to sea level rise.

           Coastal Dunes, Wetlands, and Lagoons

                Turkey has well-developed coastal dunes, especially along the western Black
           Sea coast and in the deltas of the Aegean and Mediterranean Seas. These natural
           barriers to storms would provide some defense against the consequences of sea
           level rise, at least in the short run.      Elsewhere, beach rock has developed
           along numerous low soil cliffs.

                Wetlands are mostly confined to relatively narrow areas in the Kizilirmak,
           Yesilirmak, Seyhan, and Ceyhan Deltas and in other low coastal reaches along the
           Aegean Sea, most of which are associated with lagoons. There are no coral reefs,
           mangroves, or saltmarshes in Turkey.

                Lagoons are found mainly behind the coastal spits of the deltaic areas of
           Turkey. There are, however, lagoons in some inlets with high- and low-cliffed
           coasts, too. The lagoons of the Turkish coastline are used partly as salt pans
           and fish ponds.     The former lagoons of Kucukcekmece and Buyukcekmece have
           recently been converted to water reservoirs for the city of Istanbul.

                Genuine tidal estuaries are not found in Turkey, although some ria-type
           inlets are present. The ancient harbor of Istanbul, which is called Halic, is
           an example of this type of ria.


           LATE PLEISTOCENE AND HOLOCENE SEA LEVEL CHANGES

                Recent sea level changes have played a very important role in the coastal
           geomorphology of Turkey. The influence of young tectonic subsidence and uplift

                                                   187










             Mediterranean

             phenomena are observed at several points of the coastline. Alluviation, deltaic
             subsidence, and climate changes must be added to, this group.       These kinds of
             coastal processes are controlling the prograding and retrograding stretches of
             the coastline.

                  Finding some unchanging coastline stretch in Turkey is really difficult.
             Generally, the upper Pleistocene (Tyrrhenian) terraces with their fossils are
             less than about 250,000 years old, and they are found at elevations between 10
             and 80 meters in different coastal places.       Some coastal terraces and their
             fossils at about 6 to 10 meters must belong to the last interglacial period --               I
             that is, about 100,000 years ago. Moreover, on the recent coastline of Turkey,
             except prograding deltaic coastline stretches, there are traces of elevated
             former sea levels of 200 cm (about 6,000-8,000 years ago), 100 cm (about 2,000-
             2,500 years ago), and 50 cm (about 1,400 years ago) (Kayan et al ., 1983; Laborel ,
             1989; Pirazzoli et al., 1989). If we reconstruct these former traces, we may
             determine what will happen in the future.        These kinds of studies must be
             extended for all the Turkish coastline.



             CULTURAL AND ECONOMIC FEATURES

             Demography

                  Most of Turkey's population of 50 million is well out of danger from a
             rising sea. Of the 399 cities and towns in Turkey, more than half the population
             lives less than 100 meters above sea level. Unfortunately, the lack of vertical
             resolution on topographic maps makes it impossible to estimate the portion of
             the population that lives within a few meters of sea level.

             Ports

                  During ancient times, there were several harbors and cities on the coastline
             of Turkey, generally at the point where the main trade ways of the country ended,
             usually on a deltaic plain next to a low soil-cliff (Erol, 1976, 1983, 1989;
             Akurgal , 1970).    The presence of lagoons facilitated the establishment of
             primitive landing places that were later converted to harbors.       Many of these
             harbors and cities had to be abandoned because deltaic alluviation, sea level
             changes, earthquakes, and tectonic uplift shifted the shorelines (c.f. Erol,
             1963, 1983; Kraft et al., 1977, 1980a,b, 1982; Kayan, 1981, 1987).

                  In modern times, the ports have expanded and situated on much broader
             grounds. In addition to the historical ports, several smaller fishing harbors
             and shelters with breakwaters have been built.      According to Erol (1988), the
             total number of the artificial structures of Turkey     is as follows:

                          Large commercial harbors                12
                          Small harbors                          115
                          Shelters with breakwaters                9
                          Abandoned ancient harbors               44
                          Major coastal protection works           6

                                                     188










                                                                                      Ero I

              In the building of all these coastal establishments, unfortunately, sea
         level and other environmental conditions are assumed to be constant. In reality,
         even some of the new harbors have been destroyed or covered by sediments, often
         within a period less than 10 years. Warning the policy makers in Turkey has been
         extremely difficult.    In some cases, sea level rise may help to offset the
         sedimentation processes that have forced port abandonments. However, this would
         be merely a fortuitous coincidence.

         Other Land Uses

              The coastal zone has Turkey's most fertile agricultural lands and a mild,
         humid climate. In recent times, coastal tourism and yachting have experienced
         explosive growth.    The tourist establishments were first built on the narrow
         beach strip, but now they are backing up to the country's most valuable inland
         agricultural fields. The land has also been expanded toward the sea with walls,
         embankments, quays, etc. But as noted previously, the coastal lowland strip of
         Turkey is narrow at the base of inland mountains. A rise in sea level would
         force the nation either to give up agricultural lands to facilitate landward
         resettlements or to spend large amounts of money on erecting coastal defenses.

         Fisheries

              Fishing has been an attractive livelihood for the people who have lived on
         the Turkish Mediterranean coastline since historic and even prehistoric times.
         For example, in 1923, there were about 30 fish ponds on the Anatolian coastline
         with a yearly production of 9,000 tons of fish products. However, in the area
         of the Marmara Sea and Straits, the local character of fishing developed somewhat
         differently. This is because fish from the Black Sea migrate toward the Marmara
         and Aegean Seas during the autumn and winter months, as the Black Sea waters
         become cooler.   In the early years, the migrating fish were staying partly in
         the Marmara Sea during the winter season. But in recent years, because of water
         pollution and other hostile conditions, they prefer to continue their migration
         to the north Aegean Sea. Those fish return to the Black Sea during spring and
         summer seasons.    So fishermen are following the fish and are catching them,
         especially in the Anatolian coastal waters of the Black Sea, at the entrance of
         the Bosphorus, and in the Marmara and north Aegean Seas.             Under these
         circumstances, fish production has increased yearly from 79,000 tons (1952) to
         532,000 tons (1985).     The percentage of this production is distributed as
         follows:

                                                            ra.
                       Black Sea                            80
                       Marmara Sea and Straits              12
                       Aegean Sea                            5
                       Mediterranean Sea                     3

              Climate change could affect the fisheries in many ways.     Although Turkey
         does not have extensive wetlands, many of the fish caught there spend part of
         their lifetimes in the marshes found elsewhere.       Warmer temperatures could
         encourage some of the fish that migrate out of the Black Sea during the winter
         to remain there longer. On the other hand, warmer temperatures might amplify

                                                189








              Mediterranean

              pollution problems.     The unknown impact of global warming on seasonal
              precipitation, river flow patterns, and currents also could be important.


              CONCLUSION

                  An evaluation of the implications for Turkey leads one to realize that
              worldwide, sea level rise would be a serious problem. Turkey would appear to
              be one of the countries least vulnerable; yet even here, the consequences could
              be severe.

                   Clearly, policy makers need to take sea level rise into account. Even in
              the short run, doing so would help to ensure that new development is consistent
              with current environmental changes.    In the long run, it is important both
              because our valuable coastal strip is very narrow and because it would help
              introduce policy makers to the other consequences of the greenhouse effect, such
              as hotter summers and more droughts, which in Turkey could be far more
              devastating.

































                                                    190











                                                                                             Ero I



                        APPENDIX: CLINATOLOGY AND CURRENTS OF TURKISH WATERS


                The climate conditions that control the recent phenomena are determined by
           the main physiographic features. The country lies between the middle latitude
           and Mediterranean macroclimatic zones and has a transitional character.             The
           Middle European and Mediterranean climates alternatively dominate in the Black
           Sea region, whereas only the Mediterranean climate dominates south of the Taurus
           Mountains and in the Aegean Sea region. The climate of the Marmara region is
           transitional between the Black Sea and Mediterranean types. In the central part
           of the Anatolian Peninsula, which is between the North Anatolian and Taurus
           Mountains, a continental plateau type of Mediterranean climate is characteristic.
           The types of coastal regions found in Turkey are shown in Figure A-1.

           Black Sea

                The climate of the Black Sea coast of Turkey is mainly under the influence
           of northerly winds (air masses) that usually blow as gales called Karayel (black
           winds) in Turkish. Because of the long fetch (i.e., distance over which waves
           can form) in the Black Sea and the absence of islands along this somewhat
           straight coastline, the wave energy is considerable. Thus, rapidly retrograding
           high coastal cliffs and shingle beaches at the north of the short mountain rivers
           are predominant along this coastline. The sandy beaches and their related dunes
           are also developed under the influence of these strong northerly winds.

                The heavy rainstorms and strong northerly winds that dominate the winter
           climate (temperature 0 to 70C) of the Turkish Black Sea coasts yield to mild
           winds during the summer. Except for some rare winds in the eastern part of the
           coastline, the influence of the southerly winds is extremely rare in the Black
           Sea coastal strip of Turkey. Therefore, the summers are also mild (19 to 230C),
           cloudy, and rainy in this area. The temperature of the seawater is cool (15 to
           160C), and the surface of the Black Sea is mainly rough.

           Marmara Region

                The North Anatolian Mountain chain usually prevents the penetration of the
           marine climate influences inland--that is toward the main plateau of Central
           Anatolia, especially in the middle and eastern parts of the country. But in the
           west, toward the Marmara Region, the climatic influence of the northerly winds
           and air masses can easily penetrate to the south during the winter and summer
           seasons. But usually these northerly weather conditions alternate with southerly
           conditions.    In Istanbul, for example, the southerly gales alternating with
           northerly winds have an important effect. The Maramara Region with cold (I to
           60C) rainy winters and cool (22 to 23'C), windy summers is a transitional area
           between the Black Sea and the Mediterranean environments.              These cl i mate
           characteristics as well as sea currents in the straits are also controlling the
           physical properties of the water masses in the Marmara Sea.



                                                    191











               Mediterranean

















               3




                                                                         0         200-km


                                                                            Mountaln ridges
                                                                      ;--4- Deltaic areas




               Figure A-1. Types of coastal regions of Turkey: (1) Black  Sea type;   (2).Maramara
               type; (3) Aegean type; and (4) Mediterranean type.


               Aegean Sea

                   The climate in the Aegean Sea is a transitional blend of the climate between
               the Black Sea and the Mediterranean Sea. But there the Mediterranean climate
               dominates mainly during the summer, whereas the Black Sea conditions dominate
               during the winter in the Marmara region. However, because of the northerly cool
               to warm (26 to 280C) summer winds in the Aegean Sea, the summers are cooler than
               the eastern Mediterranean area, and this climate characteristic also controls
               the summer seawater temperatures (16 to 190C) of the Aegean Sea.

                   Along the Mediterranean coast of Turkey, the Mediterranean climate
               dominates.   Warm (24 to 29'C), dry, and calm weather conditions are very
               conducive to the development of biogenetic coastal forms aswell as dunes and
               beach rock. The rainy, cool to warm (9 to 110C) winters and wave activity cause
               the formation of wide, sandy beaches. The excessive summer evaporation causes
               cementation in the beach sands or calcite concentrations in the coastal to inland
               soils. Investigations have shown that similar conditions were prevalent in this
               part of the coastline during the Holocene and even during the upper Pleistocene
               (Erol, 1983; Kayan et al., 1983; Laborel, 1989).


                                                      192











                                                                                     Ero I

         Marine Hydrology

         Water Masses

              The Black Sea in the north and the eastern Mediterranean in the south are
         Turkey's two main sources of water masses. The water masses originating from
         the Mediterranean Sea are principally warm (21.540C on the surface) with high
         salinity (39.15 parts per thousand), and the water masses in the Black Sea are
         cool (8 to 15% on the surface) with low salinity (18.36%).    In the area of the
         Marmara Sea and Straits, there are transitional conditions between the Black Sea
         and Mediterranean masses. Indeed, the warm and saline Mediterranean water flows
         on the surface along the Anatolian coast toward the north in the Aegean Sea
         (Figure 3) and meets the cool and less saline Black Sea water.         There the
         lighter, less saline Black Sea water flows on the surface toward the south, and
         relatively heavy saline Mediterranean water flows under it toward the north into
         the Dardanelles Strait. These layered surface and deep-water masses also occur
         in the Marmara Sea and Bosphorus Strait.

              The mean surface temperature in the Marmara Sea is 15 to 170C. The surface
         temperature of the seawater is 8 to 90C in January and 24 to 260C in August.
         The salinity of the surface waters is 23.47%, and that of the deep waters is
         38.64%.

              The characteristics of deep seawaters are also influenced by the surface
         conditions. In the eastern Mediterranean, there are four layers of water masses
         (Yuce, 1987):    (1) surface waters of Atlantic origin (temperature 21.540C,
         salinity 39.15%); (2) intermediate eastern Mediterranean waters (temperature
         15.5*C, salinity 39.15%); (3) deep water (temperature 12.60C, salinity 38.4%);
         and (4) Bottom water.

              In the Black Sea, there are three layers of water masses: (1) surface water
         in the upper 200 m (temperature 8 to 150C, salinity 18%); (2) transitional water
         layer; and (3) deep water (temperature 90C, salinity 22.5%).

              The surface temperatures drop below the freezing point, especially in the
         north and western coasts of the Black Sea, and ice masses may penetrate through
         the Bosphorus to the northern Marmara Sea (Erinc, 1985).

         Currents

              The characteristics of the currents in the straits and Marmara Sea are
         principally influenced by the salinity and temperature differences between the
         Black and Mediterranean Seas. The water volume brought by rivers into the Black
         Sea Basin is great, and because of this, the surface level of the Black Sea is
         50 cm higher than that of the Marmara Sea.      This is another reason for the
         currents in the straits.

              The winds are a significant infl*uence on the currents in the Bosphorus.
         Normally, the surface current in the Bosphorus is from north to south.         Its
         velocity is directly under the control of the dominant northerly winds, and it

                                                193









              Mediterranean

              may reach up to 9-10 km/h. But it may decrease or completely disappear when the
              southern winds blow persistently for a few days, especially during the southerly
              gales. In this case, the warm and saline Mediterranean deep water may rise to
              the surface. This kind o  'f unusual sudden change causes mass mortality of fish
              that live in the upper, less-saline, cool waters and also of fish that live in
              the deeper, saline, and warm water layers.

                   Because of the strong underwater currents, the bottom of the Bosphorus is
              partly bare of fine sediments or is covered in-some places by larger particles
              of sands and even shells. The water exchange between the Black and Mediterranean
              Seas has been studied by several authors since the 19th century (e.g., Makarov,
              1885; Wharton, 1886; Ullyott and Ilgaz, 1946; Pektas, 1953; Yuce, 1985, 1987b).
              The influence of the currents in the area of the straits and Marmara Sea has also
              been discussed by Stanley and Blanpied (1980). According to these authors, the
              sea level changes during the late Holocene was the most important factor
              controlling the currents in this area.

                   In the Marmara Sea, the surface currents are directed from the Bosphorus
              toward the Dardanelles Strait with a maximum speed of 2.5 km/h, and a minimum
              speed of 750 m/h (Figure. A-2).     In the Dardanelles Strait, similar to the
              Bosphorus, the Black Sea water flows on the surface from north to south, and  the
              Mediterranean water flows as an undercurrent toward the north. Because of     the
              strong mixing on the boundary of these two counter- currents, the salinity of the
              surface water increases rapidly here. It is 18% in the north Marmara Sea, it
              becomes 25% in the Dardanelles, and 37.52% in the north Aegean Sea. There,    the'
              surface temperature is at a maximum of 24.110C in August and a minimum of 13.330C
              in March. Toward the southern Aegean Sea, the surface waters coming from the
              Black Sea gradually disappear.

              Dissolved Oxygen

                   The amount of the dissolved oxygen, especially in the surface water masses,
              plays an important role in the biologic properties of the sea. The boundary of
              this dissolved oxygen surface layer is 150-300 meters in the Black Sea. Below
              this level is an anaerobic (due to high levels of H,S) water body, as in the
              Marmara Sea. This deep layer is not found in the Aegean and Mediterranean Seas.

              Wave Conditions

                   The wave conditions on the surface of the seas surrounding Turkey is under
              the control of wind direction and its velocity and the fetch distances. But,
              since satisfactory studies on fetch are missing, only the conditions of wave
              heights and directions will be explained here.

                   In the Black Sea, northerly and northwesterly winds are dominant especially
              in winter months. Because the fetch distance is great in this direction, waves
              are high and they strongly erode the foot of high cliffs on the coastline of the
              North Anatolian Mountain chain. The strong southwesterly winds in the Marmara
              Sea blow sometimes as gales and they alternate with northern winds.        In the
              Aegean and Mediterranean Seas, the southwesterly winds influence the coastline
              during the winter, whereas the moderate northerly winds prevail during the
              summer, especially in the Aegean Sea.

                                                     194







                           25           30            35          40                  Ero 7


                            M







                                                            SEX

                                             ACY,


                                                                             40





                                                   yEf





                              a                                              39
                                  10,




                                                SEX
                        MEDITERR",
                                            of ()
                                                                          5W


                                                 -30

          Figure A-2. Surface currents in the seas surrounding Turkey.


               The height of the waves and related wind directions are as follows:

                                     Mean                    Maximum

               Black Sea              N3-4           Up to 13 m in winter
               Bosphorus              NI
               Marmara Sea          SW 3-4           Up to 4-6 m in winter
               Dardanelles          SW 1-2
               Aegean Sea           SW 3-4
               Mediterranean        SW 3-4           Up to 8-9 m in winter
                 Sea

               The tides and other sea level fluctuations are small along the Turkish
          coastline. The daily periods of the tides are as follows:

                                                 195











              Mediterranean

                    Black Sea             maximum   10  cm
                    Bosphorus             maximum  2.5  cm
                    Marmara Sea           maximum  2.5  cm
                    Aegean Sea            maximum   30  cm
                    Mediterranean Sea     maximum   30  cm
                    Izmir Gulf            maximum   50  cm
                    Iskenderun Gulf       maximum   50  cm

                    The pattern of   storm surges   (compared to mean sea level) are as follows
              (Aykulu, 1952):

                    Marmara Sea           maximum  101 cm
                    Aegean Sea            maximum  122 cm  in Izmir
                    Black Sea             maximum   65 cm  in Eregli

                    According to historical records       in Turkey and surrounding        countries,
              tsunamis and other rapid sea level changes were frequently observed (Soysal,
              1985). The waves may not be very high, but they are destructive. Some of them
              may be only storm surges, but the others must be tsunamis.          This kind of wave
              was especially destructive at the Izmit Gulf and at the estuary of Istanbul-
              Halic Harbor in the Marmara Sea, at the Izmir Gulf and Islands in the Aegean Sea,
              and at the Fethiye Gulf in the Mediterranean Sea.


              BIBLIOGRAPHY

              Akurgal, E. 1970. Ancient civilization and ruins of Turkey, 2. Ed. .. Istanbul.

              Bener, M. 1974. Beachrock formations on the coastline between Alanya-Gazipasa,
              southern Turkey.      No. 75, 95.      Istanbul:     Geographical Institute of the
              University of Instanbul.

              Bird, E.C.F. 1980. Sea Level Curve. Monde. 24 e Congr. Intern. Geogr. Japan.
              IGU-CCE Project One.

              Bird, E.C.F.     1985.  Coastline Changes:    A Global Review, 219 pp.      John Wiley
              Sons Ltd.

              Erinc, S.      1985  Relationship between the ice formation and meteorological
              conditions in Black Sea. Istanbul Univ. Deniz Bilimleri ve Cogr. Enst. Bulteni
              2:11-16. Istanbul.

              Erol, 0.     1963. Asi Nehri deltasinin jeomorfolojisi ve dorduncu zaman deniz-
              akarsu seki leri. Die Geomorphologie des Orontes Deltas und der anschliessenden
              Pleistozaenen Strand- und Flussterrassen, Provinz Hatay, Turkei. Ankara Univ.
              Dil ve Tarih-Cografya Fak. Yayini. No. 148, 11 s. Ankara.

              Erol , 0. 1969. Observations on Anatolian coastline changes during the Holocene.
              Cogrefya Arast. Derg. 2:89-102. Ankara.


                                                        196











                                                                                                  Ero I

           Erol , 0.    1972.   Beachrock formations on the western coasts of the Gelibolu
           Peninsula,   Dardanelles, Turkey (S). Cogr. Arast. Derg. 3-4:1-12. Ankara.

           Erol, 0.     1976.   Quaternary shoreline changes on the Anatolian Coasts of the
           Aegean Sea   and related problems. Bull. Soc. Geol. France 18, 2:459-468, coll.
           Internat. CNRS Paris No. 244:263-272. Paris.

           Erol, 0. 1981. Heotectonic and geomorphologic evolution of Turkey. Neve Folge
           Suppl. Bd. 40:193-211. Berlin-Stuttgart.

           Erol, 0. 1982. Geomorphological Map of Turkey.            1:2 million. Ankara: Mining
           Research and Exploration Institute of Turkey.

           Erol, 0. 1983. Historical changes on the coastline of Turkey. Bird, E.C.F.,
           Fabri, P. (eds). Coastal problems in the Mediterranean Sea. Proceedings of a
           symposium held in Venice 10-14 May 1982. Int. Geographical Union, comm. on the
           Coastal Environment:95-108. Bologna.

           Erol, 0. 1985. Turkey and Cyprus. In Bird, E.C.F., Schwartz, M.L. (eds). The
           Worlds Coastline:491-500. Van Nostrand Reinhold Co., New York.

           Erol, 0. 1987. Quaternary sea level changes in the Dardanelles Area, Turkey.
           Ankara Univ. Dil ve Tarih-Cogarfya Fak. 60. yil armagani:179-187. Ankara.

           Erol, 0.     1987.  Turkey.    IGCP Project 200:Late Quaternary Sea Level Changes:
           Measurment, Correlation and Future Applications. Summary Final Report. Ed. by
           P.A. Pirazzoli. Nivmer Information No. 14:38-40. Paris.

           Erol, 0.     1988.    Turkey.     In Walker, H.J. (ed)       Artificial Structures and
           Shorelines:241-252. Kluwer Academic Publishers.

           Erol, 0.     1989a.   Holocene development stages of the Ceyhan and Seyhan river
           deltas, southern Turkey. (Baskida, in print).

           Erol, 0. 1989b. Anatolia, Turkey. Encyclopedia of Geoarcheology. (In print).

           Erol, 0. 1989. Anatolian historical harbours. Encyclopedia of Geoarcheology.
           (In print).

           Erol, 0. 1989. Geomorphological Map of Turkey. 1:1 million. Publ. of M.T.A.
           Ankara. (In print).

           Erol, 0.    1989. A geomorphological approach to the application of the Laws for
           the coastal protection in Turkey.         Istanbul Univ. Deniz Bilimleri ve Cografya
           Enst. Bulteni 6. Istanbul. (In print).

           Evans, G.       1971.     The recent sedimentation of Turkey and the adjacent
           Mediterranean and Black Seas: A review. Campbell, A.S. (ed). Geol. and Hist.
           of Turkey:385-406. Tripoli.


                                                       197











               Mediterranean

               Evans, G. 1975. Recent sedimentation of the southern Turkish coast and adjacent
               Mediterranean     between   Cyprus   and   Turkey.      Imperial    College, . London.
               (Unpublished)

               Flemming, N.C.     1968.   Archeological evidence for sea level changes in the
               Mediterranean. Underwater Assoc. Report:9-12.

               Flemming, N.C.    1971. Cities in the Sea. Doubleday and Co., 222 p., New York.


               Flemming, N.C.,   Czartoryska, N.M.G., Hunter, P.M. 1973. Archeological evidence
               for eustatic and tectonic components of relative sea level change in the South
               Aegean. Blackmann, D.J. (ed). Marine Archeology. London: Butterworths.

               Gozenc, S., Gunal, N.      1987.    Urban and rural population in Turkey and the
               distribution of urban population according to the altitudes on a map of 1:200
               000 scale.    Istanbul Univ. Deniz Bilimleri ve Cogr. Enst. Bulteni 3:27-38.
               Istanbul.

               Kayan, 1. 1981. Effects of natural environment on changing Aegean civilization
               (Abstract). Ankara.

               Kayan, 1.    1987.  Late Holocene sea level changes along the western Anatolian
               Coasts.   Late Quaternary sea level correlations and applications.            Dalhousie
               Univ. Halifax, Canada. July 19-30, 1987. Abstracts: 15.

               Kayan, I., Kelletat, D., Venzke, J.F.         1983.    Morphogenetic and geodynamic
               evolution of the coastal strip between Karaburun and Figla Burnu in the west of
               Alanya, south coast of Turkey.       Torkiye Jeologi Kurultayi 163-165.         Ankara.
               (Abstract)

               Kraft,    J.C.,   Aschenbrenner,    S.E.,   Rapp,   G.      1977.      Paleogeographic
               reconstructions of coastal Aegean archeological sites. Science 195:941-947.

               Kraft, J.C., Kayan, I., Erol, 0.        1980a.   Geographic reconstructions in the
               environs of ancient Troy. Science 209.4458:776-782.

               Kraft, J.C., Aschenbrenner, S.E., Kayan, I.          1980b.    Late Holocene coastal
               changes and resultant destruction or burial of archeological sites in Greece and
               Turkey. Proc. CCE Field Symp. Japan. IGUComm. Coast. Env.:13-31. Bellingham
               USA.

               Kraft, J.C., Kayan, I., Erol, 0.             1982.     Geology and paleogeographic
               reconstructions of the vicinity of Troy. In Rapp, G., Jr., Gifford, J. (eds).
               Troy. Supplementary Monograph 4:11-42. Princeton Univ. Press.

               Kraft, J.C., Belknap, D.F., Kayan, 1. 1983. Potentials of          discovery of human
               occupation sites on the continental shelves and nearshore coastal zone.               In
               Masters, P.M., Flemming, N.C.        (eds).     Quaternary Coastlines and Marine
               Archeology:87-120. Academic Press.

                                                         198











                                                                                              Ero I


           Kraft, J.C., Kayan, I., Aschenbrenner, S.E. 1985. Geological studies of coastal
           change applied to archeological settings.          Rapp, G., Gifford, J.A. (eds).
           Archeological Geology. Yale Univ. Press.

           Laborel, J. 1989. The oyster-vermetid formations of the southeastern coast of
           Turkey (Region of Samandag -estuary of the Orontes River).                In Biogenic
           Constructions in the Mediterranean, a review.        Scientific reports of the Port
           Cros National Park. (In print).

           Makarov, S.     1985.    On the water exchange between the Black Sea and the
           Mediterranean Sea. Proc. Sci. Imp. Acad. St. Petersburg 51:6. (In Russian).

           Neumann, W. 1954. Natural causes of mass-mortal of fishes in the Bosphorus.
           Hidrobiologie Mecm. Seri A. 2.2:74-77. Istanbul.

           Pektas, H. 1953. Surface currents in the Bosphorus and Marmara Sea.
           Hidrobiologie Mecm. Seri A. 1.4:154-169. Istanbul.

           Pirazzoli, P.A., Laborel, J., Saliege, J.F., Erol, 0., Kayan, 1. 1989. Holocene
           raised shorelines from Hatay (Turkey): paleoecological and tectonic implications.
           (In preparation).

           Soysal, H.    1985.   Tsunami and Tsunamis that effect Turkish coasts.         Istanbul
           Univ. Deniz Bilimleri ve Cografya Enst. Bulteni 2:59-66. Istanbul.

           Stanley, D.J., Blanpied, C. 1980. Late Quaternary water exchange between the
           Eastern Mediterranean and the Black Sea. Nature 285:537-541.

           Sengor, A.M.C., Canitez, N.         1982.    The North Anatolian Fault.          Alpine
           Mediterranean Geodynamics, Geodynamic Series 7:205-216.

           Titus, J.G., Leatherman, S.P., C. Everts, D. Kriebel, and R.G. Dean. 1985.
           Potential Impacts of Sea Level Rise on the Beach at Ocean City, Maryland.
           Washington, D.C.: Environmental Protection Agency.

           Ullyott, P., Ilgaz, 0.         1946.    The hydrography of the Bosphorus.            the
           Geographical Review 36:44-46.

           Wharton, W.J.L. 1886. Report on the currents of the Dardanelles and Bosphorus.
           Admirality. London.

           Uslu, T.   1977.   A plant ecological and sociological research on the dune and
           Maquis vegetation between Mersin and Silifke.         Sommunications de la Fac. des
           Sciences de I'Univ. d'Ankara. Serie C. Botanique 21.1:1-60. Ankara.

           Yuce, H.    1985.   Change of deep water salinity in Black Sea.         Istanbul Univ.
           Deniz Bilimleri ve Cogr. Enst. Bulteni 2:93-98. Istanbul.



                                                     199











               Mediterranean

               Yuce, H.    1986.   Water level changes in the Bosphorus.        Istanbul Univ. Deniz
               Bilimleri ve Cografya Enst. Bulteni 3:67-78. Istanbul.

               Yuce, H.     1987a.   Characteristics of mean surface temperature- sal i ni ty and
               dissolved oxygene variations in the Aegean Sea. Istanbul Univ. Deniz Bilimleri
               ve Cogr. Enst. Bulteni 4:105-116. Istanbul.

               Yuce, H.     1987b.    Formation and distribution of the water masses in the
               northeastern Mediterranean Sea. Unpublished Doctorate thesis. Istanbul Univ.
               Deniz Bilimleri ve Cografya Enst. Istanbul. 151 pp.







































                                                         200










            THE INFLUENCE OF SEA LEVEL RISE ON THE NATURAL AND
                   CULTURAL RESOURCES OF THE UKRAINIAN COAST


                                         YURII D. SHUISKY
                                       Geography Department
                                     Odessa State University
                                    Ukraine, 270000 U.S.S.R.






           INTRODUCTION

               The Union of Soviet Socialist Republics has a larger mainland coastline than
           any other nation. However, concerns about global warming have not focused on sea
           level rise as much as on other implications of global warming.     This relative
           emphasis is reasonable when one realizes that most of the Pacific, Arctic, and
           Baltic coasts are sparsely developed and that much of this coastal area is
           currently experiencing uplift.      Aside from Leningrad, the most important
           exception is probably the Ukrainian Black Sea coast. Unlike most other parts of
           the U.S.S.R., this is a warm coast with a low barrier appropriate for tourism and
           substantial fishing that depends on natural systems that are sensitive to sea
           level.

                Because no research has been done on the subject, we are unable to present
           any quantitative estimates of the impacts of accelerated sea level rise, and the
           lack of policy assessments makes it impossible for us to discuss response
           strategies. With those limitations, this paper briefly describes the activities
           along the Ukrainian Black Sea coast that seem vulnerable to a 50- to 200-cm rise
           in sea level, characterizes the coastal environment, and summarizes existing
           research on sea level trends and related coastal processes. We hope that this
           paper helps to encourage officials in the Ukrainian Republic to begin considering
           the implications of global warming and sea level rise.


           RESOURCES AT RISK TO A RISE IN SEA LEVEL

                The Black Sea coast of the Ukranian Republic is heavily developed and is one
           of the most populated coasts in the U.S.S.R.          Fortunately, most of the
           development is concentrated on the highlands.        Nevertheless, some coastal
           barriers and low terraces with elevations between I and 5 meters are completely
           occupied with buildings, including port facilities,  sanatoriums, holiday homes,
           and camping establishments. The barriers along the  Sukhoy and Adjalyk Lagoons,


                                                  201











               Mediterranean

               for example, have considerable    port facilities. All of these economic. resources
               would be at risk from a 50- to 200-cm rise in sea level.

                    The Sasyk Lagoon near the     mouth of the Danube has been transformed into a
               freshwater- basin, with river water used for irrigation. To prevent seawater from
               encroaching during heavy storms, a 12-kilometer-long, 4-kilometer-high dike was
               built; however, sea level rise could threaten the dike unless additional
               protection is constructed.

                    Along the Sasyk (near Eupatoria) and Dniester Lagoon, the coastal barriers
               have railroads and highways. For almost 40 years, the retreating shores have
               created difficulties for these critical transportation links, especially on the
               Dniester barrier. As a result, the Dniester barrier has been protected with a
               5,000-foot-long concrete structure and rip-rap.          On some parts of the Sasyk
               barrier the highway has been rebuilt somewhat inland.              On the Tiligul and
               Kujalnik barriers, the highway is about 200 meters inland on a dike with an
               elevation of about 5 meters.

                    Because the coastal barriers are only 1 to 5 meters above sea level, future
               sea level rise threatens the aquaculture in the lagoons behind them. To prevent
               problems in the Usunlar, Burnas, and a few other barriers, the dunes have been
               artificially elevated.     Because the Shagany, Alibey, Budaki, Tiligul, Usunlar
               limans are important for fish breeding, stabilizing barriers in front of the
               lagoons is important.

                    The natural conditions of     the Black Sea coast encourage erosion and cliff
               retreat; average annual cl i f f eros i on rates range f rom 0. 1 to 4. 5 meters per year
               (Shuisky and Schwartz, 1988). More than half of all the coastal protection
               structures attempt to retain artificial beaches, mainly groins and breakwaters.
               Seawalls are less widespread, and there are very few rip-rap structures.               An
               accelerated rise in sea level would clearly diminish the effectiveness of
               existing structures, and probably necessitate increased artificial replenishments
               of beaches, as has already occurred in other countries.

                    The largest portion of the shoreline protected from landslides is along the
               Crimea coast, where 50 kilometers (almost 15% of the coast) -- mainly from Sarych
               Cape to Alushta -- is protected by short concrete groins with artificial gravel
               beaches between them. On the western Crimea coast, 5 kilometers are protected
               near Eupatoria, Saky, and Nikolayevka. Around Skadovsk the shore is protected
               by a one-kilometer-long seawall and an artificial beach, and there is a seawall
               of about 2 kilometers (concrete and rip-rap groins with an artificial sand beach)
               near Port Zhelezny. All of these structures will have to be fortified.

                    In a number of cases, artificial beaches have been used. The District of
               Ochakov, Koblevo, and along Odessa Bay each have about 2 kilometers of protected
               shore (solid concrete and stabilized slopes).        In the City of Odessa, the shore
               is strengthened for 12 kilometers from Langeron Cape to Bolshoy Fountain Cape.
               Coastal protection structures were built near Illichevsk and on the Dniester
               barrier. All of these artificial beaches would require additional fortification
               as sea level rise accelerates...

                                                         202









                                                                                            Shuisky

                Neither the U.S.S.R. nor the Ukraine has a single organization to deal with
           research on and exploitation of the natural and cultural resources of the Black
           Sea coastal zone as a whole.          Instead, several regional organizations are
           responsible for part of the problem, for example, the Ukrainian Institute of
           Communal Building (Odessa) in the Ukraine, the Sea Coast Protecting Concern
           (Krasnodar) and the Sea Hydrotechnical Construction Institute (Sochi) in Russia,
           and the Sea Coast Protecting Concern (Tbilisi) in Georgia. Some aid is rendered
           by other organizations, such as the Sea Institute in Odessa, the Geological
           Station in Yalta, and the Hydrological Station in Vilkovo. Scientific research
           is carried out by laboratories and scientific groups in the Universities of
           Odessa, Rostov, Kuban, Moscow, and Kiev.

                  No administrative or economic organization on the Black Sea coast is
           concerned wi th sol vi ng the sea I evel ri se probl em. The 1 ack of concern i s caused
           by a number of factors, including the following: (1) the lack of reliable data
           about the disastrous effects of the rise on the natural and cultural resources
           of the Ukranian coast; (2) the relatively low rate of the rise of the Black Sea;
           (3) the economic system of the Ukraine, which does not encourage research on
           possible future disastrous consequences of the sea level rise; and (4) the low
           prestige of the scientists, whose opinion is usually ignored by state and
           economic institutions.



           THE COASTAL ENVIRONMENT

           Climate

                The average air temperature at the coast varies from 90C in the Odessa
           region to 16*C in the Yalta region. The mean temperature during the warm season,
           which lasts from April to October, is 22-240C. Maximum temperatures occur in
           August when some days reach 30-350C, the absolute maximum being 400C.

                The winter is fairly mild; in January, the average air temperature is
           -2.50C in Odessa and about 6.50C in the Yalta region.           The temperature often
           falls below -10*C, but rarely below -20*C. The absolute minimum is -280C. A
           severe winter happens once in 14-15 years, and a warm winter occurs once in 12-13
           years.

                Rain and fog prevail during the cold half of the year, and snow falls every
           year.   The precipitation     reaches 300-400 mm per year in the Odessa region,
           200-300 mm in the Tarkhankut and Kerch peninsulas, and 500-600 mm in the southern
           coast of the Crimea.

                The Black Sea water is warm; in the open sea its temperature is never lower
           than 60C, reaching 190C to 26% in July and August and up to 280C in shallow
           bays.   In the winter, the temperature falls to 2-30C at the shore; in narrow
           areas along the shores between the Danube delta and the Crimea, sea ice can
           appear, on the average, every 3-5 years. The sea freezes annually only at the
           Danube and Dnieper outfalls, and in small bays (Egorlyk, Tendra, Djarylgach,
           Perekop, and in the Kerch Strait).

                                                     203











              Mediterranean

              Geology

                   It is known (Shuisky, 1982) that the northern Black Sea coasts are
              characterized as classical liman coasts. Sediments in the limans and lagoons
              contain chemical elements and organic salts that can be used for medical
              treatment. Deposits of medicinal mud were found in the limans of Burnas, Budaki,
              Hadjibey, Mojnacki, Saky, and especially the Kujalnik liman. Those medicinal
              sediments have led to the establishment of numerous medical and sanatorium
              institutions.

                   The districts of the Danube delta, Shagany, Burnas, Kujalnik, Saky limans,
              Yalta, Theodosia, Kerch, and Skadovsk towns are the sites of mineral water baths.
              Their contents are varied including carbonates, hydrocarbonates, potassium and
              sodium, sodium and magnesium, and chalybeate waters. These deposits, too, serve
              as the basis for many medical institutions.

                   The Black Sea coast within the Ukraine borders also contains deposits of
              certain nonmetallic minerals, such as building stone, sand, gravel, pebbles, and
              sedimentary ores. The largest deposits are located near the Danube delta, near
              Odessa city, Sevastopol and Theodosia towns (building stone and raw cement
              materials), on the shores of the Jebrijan cove and Dnieper, and the Sasyk limans
              (sand and shells).

                   Among the natural resources of the Black Sea coast, the recreational
              resources are the most important. Warm water and a long warm season are the main
              factors that make the Black Sea a popular tourism and recreational area.         In
              addition, coastal sediments contain important deposits used for medical purposes.

                    Sand and pebble sediment exploitation (removal) is forbidden within the
              coastal zone. The nearshore zone is the traditional location for the fishery
              industry.   It is most intensive in the Danube, Dniester, Dnieper outfalls,
              Karkinit and Kalamit Bays, and Kerok Strait.           The biggest seaports are
              Illichevsk, Sevastopol, and Kerch.      Fish-breeding farms are situated on the
              shores of the Sasyk, Shagany, Budaki, and Tiligul limans.

                   There are many nature reserves    on the Ukranian Black Sea coast.       Their
              purpose is to save the gene banks and protect flora and fauna. The largest of
              them, the Danube reservation, is situated in the Danube outfall. It is oriented
              to ornithology and botany, as well as research on freshwater fish. In addition,
              there are important bird reservations in Chernomorsky (in Egorlyk and Tendra
              Bays) and Lebiashiy (on Lebiazhiy isles), and the Kalanchak Isles in Diarylgach
              Bay were declared reserve areas. The Martian Cape reserve on the southern coast
              of the Crimea Seas has a botanic orientation.      The Kara-Dag reserve protects
              volcanic landscapes and relief shapes, and also the precious and semiprecious
              mineral and rock deposits.






                                                     204









                                                                                           Shuisky

            SEA LEVEL MEASUREMENTS

                 There is a general awareness that the Black Sea has been rising for at least
            the past 200 years. This phenomenon was discovered by instrumented
            measurements at many locations in the U.S.S.R. and in other countries (Bulgaria,
            Romania, Turkey) on the Black Sea.

                 Although the measurements of the sea level changes began in Odessa in 1803,
            the first gauging rods turned out to be unreliable, and the data from 1870 are
            now the earliest used.        In that year, controlled gauging stations were
            established in Odessa, Ochakov, Sevastopol, and Poti, which are now sources of
            precise data about the changing level. During 1916-23, measurements were begun
            in other places, generally in seaports. The data from those observations have
            been  analyzed by many researchers          (Blagovolin and     Pobedonostzv,     1973;
            Pobedonostzv, 1972).

                 The direct observations with gauging staffs indicate a relative rise of sea
            level. On the Black Sea coast it consists of the two constituent phenomena: (1)
            the eustatic rise and (2) tectonic sinking of the littoral areas.                   The
            correlation of the eustatic and tectonic factors can differ, however, among
            various parts of the Black Sea. The level can rise, but also the littoral areas
            can rise, sink, or be stable, and the rates of these phenomena can be equal or
            unequal. It has been determined that there are 16 combinations of eustatic (E)
            and tectonic (T) factors (Shuisky, 1978).

             1.  +T>-E                   - very strong, relative sinking, never rises
             2.  +T<-E                   - strong, relative sinking, never rises
             3.  +T4>+E                  - weak, relative sinking, usually does not rise
             4.  +T<+E                   - weak, relative sinking
             5.  -T>-E                   - very weak, relative sinking
             6.  -T<-E                   - weak, relative sinking
             7.  -T>+E                   - moderate, relative sinking
             8.  -T<+E                   - strong, never turns into sinking
             9.  +T=+E                   - the level state is relatively stable
            10.  -T=-E                   - the level state is relatively stable
            11.  +T=-E                   - strong, relative sinking
            12.  -T=+E                   - strong, relative rising
            13.  Stable T with +E        - rising
            14.  Stable T with -E        - sinking
            15.  Stable E with +T        - relative sinking
            16.  Stable E with -T        - relative rising

                 This pattern of   the T and E correlation should serve as a basis for the
            coastal zone dynamics analysis.        (For the most part, the coastal zone i s
            indifferent to the causes of both stability and changing with various rates. It
            is the stability, rising, or sinking at various rates that is important. The
            actual rates of positive and negative long-term changes in different physical and
            geographic conditions of a sea coast are of particular significance.)



                                                     205










              Mediterranean

                   There is a lack of practical information in connection with sea level rise.
              Although scientific research on the process is under way, there is still no
              i nterest on the part of i ndustri al , economi c, and f i nanci al organi zati ons despi te
              the important natural and cultural resources on lowlands (Stepanov and Andreev,
              1981).   The most serious reports of the researchers on the natural processes
              connected with the sea level changes were published in collections such as "Sea
              Level Fluctuations" (Kaplin et al.,       1982a) and "The Sea and Oceanic Level
              Fluctuations" (Kaplin et al., 1982b).

                   The analysis of the modern data on   Black Sea level change within the Ukraine
              led to the conclusion that there is a     relative rise at 26 stations and sinking
              at only one (Kherson, situated in the Dnieper outfall).         The relative rising
              rates vary considerably from place to place -- from +5.10 to -1.50 mm/year (Table
              1), with an average of 1.40 mm/year. The higher rates prevail between the Danube
              Delta and Dophinovka Lagoon and in the Dnieper outfall.          The information on
              modern relative changes referred to here were verified by other geomorphological
              and geological research methods (Melnik and Mitin, 1982; Ivanov and Shmuratko,
              1982).


              SEA LEVEL RISE AND COASTAL PROCESSES

                   The influence of multicentennial sea level change on coastal development in
              different seas has been studied quite extensively. Much research was carried out
              to define the curve of sea level rise in the Holocene period using stratigraphic,
              radiocarbon, oxygen, palynologic, and archeologic methods. These studies led to
              the construction of Black Sea coast maps and the distribution maps of the
              abrasive and accumulative relief shapes for the last 50,000 years. In Odessa
              University, the climate-stratigraphic method is being worked out, based on the
              astronomic climate theory of M. Milankovich. Transferring a radiation curve into
              a climate (or eustatic) curve, we use the sea level as an integral index.

                   As far as the annual and centennial changes (algebraic sum of E and T) and
              their influence on coasts, the study of this question in the U.S.S.R. is
              inadequate at present.

                   The methods for calculating the nearshore bottom abrasion rates have almost
              been completed. These methods also take into account the T and E correlations.
              Finally, we will be able to quantitatively estimate the impact on the shore
              processes of the sea level change rates and figures.

                   But it is already obvious that a more rigorous analysis of such a phenomenon
              -- its nature and its impacts on coastal systems -- is extremely urgent. Such
              an analysis should address sea wave activity and the eustatic factor interaction.
              It is also necessary to carefully check the benchmark tidal gauges, and their
              steadiness, where especially high relative rising rates are noticed. We know
              (Klige, 1981) that about 14.3% of the general world ocean shoreline has been
              rising at more than 2 mm/year.



                                                       206









                                                                                            Shu i sky

            Table 1. Average Relative Fluctuations of the Black Sea Level Along the Shores
                     of the Ukraine (mm/year)

                                                                    Rates of sea level
                                                 Duration         fluctuations (mm/year)
                   Coastal points                years              Average    Precision


                  1.  Sulina (Romania)         1896-1988              +1.60a      ï¿½0.13
                  2.  Primorskoje              1951-1975              +1.80       ï¿½0.78
                  3.  Lebedevka                1950-1987              +1.59       ï¿½0.51
                  4.  Bugaz                    1945-1987              +2.01       ï¿½0.66
                  5.  Illichevsk               1958-1987              +1.51       ï¿½0.48
                  6.  Odessa                   1875-1988              +5.10       ï¿½0.32
                  7.  Yuzhnij                  1974-1988              +1.26       ï¿½0.43
                  8.  Ochakov                  1874-1985              +0.97       ï¿½0.27
                  9.  Nikolayev                1916-1983              +0.52       ï¿½0.19
                 10.  Stanislav                1925-1970              +0.85       ï¿½0.25
                 11.  Kasperovka               1916-1970              +2.10       ï¿½0.14
                 12.  Kherson                  1916-1987              -1.50'      ï¿½0.54
                 13.  Gerojskoye               1951-1986              +3.70       ï¿½0.79
                 14.  Tendra Spit              1885-1987              +2.26       ï¿½0.35
                 15.  Lazurnoye                1964-1988              +1.10       ï¿½0.18
                 16.  Skadovsk                 1923-1985              +0.82       ï¿½0.16
                 17.  Khorly                   1923-1985              +0.95       ï¿½0.11
                 18.  Chernomorskoye           1927-1986              +1.04       ï¿½0.41
                 19.  Tarkhankut               1878-1986              +1.21       ï¿½0.23
                 20.  Yevpatoriya              1917-1986              +0.72       ï¿½0.14
                 21.  Sevastopol               1875-1986              +0.91       ï¿½0.15
                 22.  Balaklava                1951-1985              +0.60       ï¿½0.63
                 23.  Yalta                    1928-1988              +1.10       ï¿½0.22
                 24.  Alushta                  1928-1987              +1.30       ï¿½0.33
                 25.  Sudak                    1931-1987              +0.68       ï¿½0.28
                 26.  Feodosiya                1923-1987              +0.35       ï¿½0.18
                 27.  Kerch                    1882-1970              +0.45       ï¿½0.15

            a +  = Sea level is  rising.
            b -  = Sea level  is sinking.


                 By drawing   analogies from storage lakes and from the Caspian Sea in the
            U.S.S.R., we can propose the following steps to respond to intensive sea level
            rise expected as a result of the greenhouse effect:

                    A survey of both the most and the least valuable natural and cultural
                    resources states, and of their locations along the Ukranian coast, is
                    needed.   An assessment of the morphology and coastal dynamics is also
                    important. The results should be used to identify the places requiring
                    protection from the seawater invasion --          in the first phase, second
                    phase, third phase, etc.        The financial and material resources to
                    accomplish the necessary measures must also be identified.

                                                       207









              Mediterranean

                    #  Some of the cultural resources can be relocated to secure areas. Others
                       can be dismantled because their work is complete.       The remainder may
                       need protection from the advancing sea when the level rises. Various
                       combinations of these approaches are possible.

                    0  The protection of the most valuable natural and cultural resources on
                       the lowlands can be realized by using protective seawalls or dikes,
                       following the example of the Netherlands, Belgium, Great Britain, and
                       China. The lowland in the State of New Jersey (U.S.) is also protected
                       and we have taken such experience into account here in the Ukraine --
                       not, however, as protection from the eustatic level rise, but as
                       protection from heavy storms.

                    0  Elevation of artificial sandy dunes can be used where the appropriate
                       conditions exist, especially in the areas of active wave and eolian
                       accumulation of.sandy sediments. Dune formation should precede the sea
                       level rise.

                    0  The long-term effect on the coastal zone of artificial placement of
                       sediments usually promotes the increase of beaches and accumulative
                       forms.   In the Holocene period of the Black Sea shelf, during the
                       periods of coastal zone sediment activation, the areas of accumulative
                       forms increased, and in the periods of sediment deficit, these areas
                       decreased, down to an entire washout.    In the modern stage of the Black
                       Sea coast development, most of the barriers and spits developed
                       following a sea level rise, especially where the sediment reserves are
                       sufficient.   Accordingly, we cannot rule out the possibility that the
                       coastal zone is artificially saturated with sediments that will also
                       promote the rise of the accumulation forms after the accelerated sea
                       level rise in the following decades.

                    0  Since the Black Sea coastal zone structure is very complicated, there is
                       no single step that will resolve the sea level rise problem.               A
                       combination of measures is necessary.

                    It is unclear whether the disastrous sea level rise is something certain and
              unavoidable. But in the last year, the idea of such a rise caused a tide of new
              research, which widely discussed various causes of the world ocean level's
              changing nature, including the influence of the anthropogenic factor.

                    Hoffert and Flannery (1985),came to the conclusion that the nonstationary
              impact of CO, on the climate (in the time scale of 10-100 years) is conditioned
              by simultaneous influence of several external factors (outer-atmosphere
              insolation, volcanic aerosols, concentration of CO, and the other greenhouse
              gases, and also by internal changeability of the climatic system (first of all,
              the internal oceanic dynamics).

                    In the U.S.S.R., many scientists have also come to such conclusions. For
              instance, on the basis of the analysis of the latest comprehensive observations,
              results, and climate numerical modeling, Kondratiev (1986, 1987) concluded that
              existing information is insufficient for elucidation of global climate trends and

                                                      208









                                                                                        Shuisky

           the complicated changeability and causal conditionality of climate. The tendency
           to ascribe observed climate temperature to CO, influence encounters has been
           rejected by some for a number of reasons, including the character of the
           atmosphere and ocean interaction.

                Long-term observations of the abrasion and accumulative shore dynamics cause
           me to make other correlations with the latest Black Sea level relative changes.
           The connections are not significant. The causes are still unknown, the nature
           of such interaction is not clear, and the complex analysis of the results has not
           yet been carried out. But still, the results received are sufficient to offer
           a series of theoretical theses, which can explain the causes of the modern
           seashore retreat.

                Although the Ukraine has no policy to address sea level rise, long-term
           research on the winds, waves, currents, and changing level is continuing.         In
           this case, it is important to carry out the synchronic observations of the
           cliffs, beaches, barriers, spits, and changing longshore drifts. We have already
           received such data, but laboratory work and theoretical analysis, which will be
           completed in 1990, are also required to demonstrate the connections between the
           sea level changes and the changing storm strength, and the changing sea level and
           cliff abrasion rates. We will look at the shoreline accumulative forms, retreat
           rates, drift distribution, and the interrelationships between the destructive and
           accumulating processes.


           CONCLUSION

                Before we can sensibly specify or implement policies to protect the Ukranian
           coast from rising sea level, we must understand the implications.        To do so,
           scientists will need the enthusiastic encouragement of policy officials, who have
           much of the information necessary for meaningful assessments.

                Scientists will also have to cooperate better with policy officials and with
           each other. The issue is clearly interdisciplinary, which means that the issues
           that professionals in one field prefer to study may not address the questions
           that people from other fields are -- or at least should be -- asking.        In the
           case of sea level rise, policy makers need coastal scientists to determine which
           land would be inundated or eroded, or which would experience increased flooding
           or salinization, and to assess the ecological implications; they need engineers
           to estimate the cost of protecting all the coastal areas, as well as
           recommendations for incorporating sea level rise into current infrastructure
           planning; and they need economists to estimate the costs of protection versus
           allowing the sea to advance.     In turn, the researchers need policy makers to
           provide continual guidance on the type of information most useful for decision
           making.

           BIBLIOGRAPHY

           Blagovolin, N.S., and S.V. Pobedonostsev. 1973. Recent vertical movements of
           the shores of the Black and Azov seas. Geomorphology 3:46-55 (in Russian).


                                                   209









               Mediterranean

               Hoffert,. M.I., and B.P. Flannery.         1985.    Model projections of the time-
               dependent response in increasing carbon dioxide. In: Potential Climatic Effects
               of Increasing Carbon Dioxide.          MacCracken, M.C., and F.M. Luther, eds.
               Washington, DC: U.S. Department of Energy, p. 149-190.

               Ivanov, G.I., and V.I. Shmuratko. 1982. Oceanic levels during the Pleistocene.
               In: Sea Level Fluctuations. Moscow: Moscow State University Publishing House,
               p. 60-75 (in Russian).

               Kaplin, P., R. Klige, and A. Chepalyga, eds. 1982a. Sea Level Fluctuations.
               Moscow: Moscow State University Publishing House, 310 p. (in Russian).

               Kaplin, P., R. Klige, and A. Chepalyga, eds.          1982b.   Sea and Oceanic Level
               Fluctuations for 15,000 Years.       Moscow:    Nauka Publishing House, 230 p. (in
               Russian).

               Klige, R.K.    1980.   The Ocean Level During Geological Time.         Moscow:     Nauka
               Publishing House, 145 p. (in Russian).

               Klige, R.K. 1981. Estimations of Contemporary Seashores Vertical Changing in
               Connection with Ocean's Level/Coastal Zone of the Sea. Moscow: Nauka Publishing
               House, p. 11-17 (in Russian).

               Kondratiev, K.Y. 1986. Natural and anthropogenous changing of climate. Heral
               of Acad. Sci. U.S.S.R. 10:30-39 (in Russian).

               Kondratiev, K.Y. 1987. Carbonic acid gas and climate: Data of observation and
               numerical modelling. New All-Union Geogr.Soc. 119(2):97-105 (in Russian).

               Melnik, V.I., an  d L.I. Mitin, eds.       1982.   Geology of the Ukrainian Shelf:
               Environment, History, and Methods of Investigations.             Kiev, Naukova Dumka
               Publishing House, 175 p. (in Russian).

               Pobedonostsev, S.V.     1972.    Contemporary vertical changing of the seashores
               around the European part of the U.S.S.R. Oceanology 12(4):460-469 (in Russian).

               Shuisky, Y.D. 1978. Types of Coasts of the Earth Globe. Odessa: Odessa State
               University Publishing House, 75 p. (in Russian).

               Shuisky, Y.D. 1982. Limans and liman's coasts. In: Encyclopedia of Beaches
               and Coastal Environment. Schwartz, M.L., ed. Stroudsburg: Hutchinson Ross Co.,
               p. 516-518.

               Shuisky, Y.D., and M.L. Schwartz. 1988. Human impact and rates of shore retreat
               along the Black Sea coasts. Journal of Coastal Research 4(l):405-416.

               Stepanov, V.N., and V.N. Andreev.         1981.    The Black Sea -- Resources and
               Problems. Leningrad: Hydrol.-Meteorol. Publishing House, 157 p. (in Russian).




                                                         210










                        COASTAL MORPHOLOGY AND SEA LEVEL RISE
                                    CONSEQUENCES IN TUNISIA


                                           DR. AMEUR OUESLATI
                                         University of Tunisia
                                              Tunis, Tunisia






           INTRODUCTION

                 The consequences of sea level rise are already evident on the 1300-km
           Tunisian coast (Oueslati et al., 1987). Almost the entire landscape of beaches,
           rocky low coasts, salt marshes -- and particularly cliffs -- is retreating
           (Oueslati, 1989). In many cities, erosion is threatening hotels, dwellings, salt
           pans, industrial establishments, and the public infrastructure; the nation's
           archeological heritage is also at risk. The few sections of the           coast not yet
           suffering erosion are generally in undeveloped areas at the mouths        of rivers and
           the bottom of some bays.

                 The vulnerability of the Tunisian coast has been particularly evident in the
           aftermath of storms.      For example, a January 1981 storm in the       Gulf of Tunis
           caused severe damage and completely removed beaches along many stretches of
           coast, especi al ly the suburbs of the capi tal . Wi th a stabl e sea I evel , the waves
           could have rebuilt these beaches after the storm. But the Bruun Rule shows that
           when sea level rises, offshore portions of the beach system must gradually rise
           as well, implying that much of the sediment deposited offshore during storms will
           remain there. The experience in Tunisia after the 1981 storm has been consistent
           with this theory.

                 Water tables are also rising, with a resulting salinization of low-lying
           areas, particularly in subsiding areas such as those along the Gulfs of Tunis and
           Gabes (Oueslati, 1989). Rising seas have also transformed many occupied (in
           ancient times) areas into wetlands, and may soon do the same to the cultivated
           areas of antiquity (Oueslati, 1989; Paskoff and Oueslati, in press).

                 In response to these problems, coastal defense structures are becoming
           increasingly common on the Tunisian coast.           Seawalls are most common, with
           dimensions scaled to the size and value of the buildings being protected. Along
           the Gulf of Tunis and at Mahdia, the structures are very large.            On the other
           hand, many human activities are increasing the vulnerability of the coast:
           extraction of beach sand for construction and the loss of marine vegetation as
           a result of pollution directly weaken the coast.             Dams for managing water

                                                      211










              Mediterranean

              resources and jetties at harbor entrances diminish the natural supply of
              sediment, which might otherwise offset some of the erosion (particularly in cases
              where the littoral drift is mostly in one direction, such as Bizerte and Ghar el
              Mebah, where beaches downdrift of the jetties are eroding rapidly).

                   The next two sections briefly summarize the likely impacts of an accelerated
              rise in sea level on the Tunisian coast and the possible responses. Although
              Tunisians have not studied in detail the implications of sea level rise for each
              particular coast, the reader can better understand our vulnerability by
              considering the environmental conditions of the coast in more detail; this
              information is provided by the final sections of this paper.


              IMPACTS OF ACCELERATED SEA LEVEL RISE

                   About half of Tunisia's population and most of its major cities are on the
              coast (Figure 1). The many ports range from industrial-sized harbors to those
              servicing small fishing or pleasure villages. Most of the nation's industrial
              and tourist establishments, and all of its salt production facilities, are very
              close to the shore.    The remainder of the coastal lowlands are cultivated --
              mostly for cereals, although fruits and vegetables are also profitable in the
              Medjerda River Delta and around urban areas where they can be sold to local
              residents. All of these activities are at risk.

                   A rise in sea level of 50 to 200 centimeters would almost undoubtedly result
              in a great retreat of the entire coast, the extension of salinized areas, and the
              disappearance of some natural systems. Along the Gulf of Tunis, important parts
              of the Medjeida delta (Figure 1) and the Milian plain would be inundated; most
              lagoons either would disappear or would be shifted substantially landward; and
              Tunis and its suburbs would be seriously threatened. Along the Gulf of Gabes,
              coastal systems could probably shift landward. New wetland ecosystems may form
              on the alluvial plains where the current ecosystems are inundated.        Figure 2
              illustrates the Kerkna archipelago, where the outer parts of Sfax and Gabes may
              be seriously damaged -- perhaps even more than Tunis, given current subsidence
              trends. Sea level rise at sfax is estimated to be 5.7 mm/yr, a rate almost four
              times higher than the worldwide average (Pirazzoli, 1986).

                   In the central part of Hammamet Gulf, the most important impact would be
              saltwater intrusion into cultivated alluvial plains. Meanwhile, the wetlands
              behind the foredunes,may be converted into open-water lagoons. Cities in the
              northern and southern parts of this gulf may be severely damaged, especially the
              large tourist complexes of Hammamet and Sousse Monastir. Along the eastern coast
              of the Cap Bon peninsula and at Dimass, the lagoons seem likely to be completely
              lost, because rocky high ground (a consolidated Tyrrhenian bar) immediately
              inland would preclude a. landward migration. Similarly, in the Sahel, the narrow
              alluvial plain would be squeezed between an advancing shore and the rocky high
              ground.

                   Rising sea level'also threatens fishing, a major occupation and an important
              Tunisian tradition.. The two largest fisheries are located at the inlets of the

                                                     212











                                                                                                                        Oueslati



                                                                           6
                                                                 3 2          7

                                                            2               8

                                                                       10
                                                                                               13


                                                                                              is

                                                                                    12           is

                                                                                           is



                                                                                         0 19





                                                                                  21


                                                                                                 22
                                                                                                   24
                                                                                           23          25

                                                                                                   6
                                       a

                                              5 25 100 3W     vW
                                               is so                                               27   0

                                       b
                                          25@
                                          Is                                          28
                                       C
                                          10
                                          5                                                             30 9
                                          2                                                        31
                                          1                                               32
                                       d
                                                                                  33
                                       e

                                       f
                                                                              0
                                                                                 34                5



                                                                                                       37






                                                                                 0              Sok"



                Figure 1.       Cultural and economic features (urban population, hotels, and ports)
                [Legend:       a = towns wholly or partly installed on unconsolidated lowlands -
                1,000s of      inhabitants; b = zone occupied by important tourist area; c = hotel
                capacity        1,000s of beds; d = ports; e = fishing ports; f = marina]

                                                                       213










              Mediterranean

















































                                            4Km




             Figure 2.  Kerkna archipelago -- possible consequences of 50, 100, and 200 cm
             rise in sea level (hatched areas would be invaded by sea water).

                                                   214











                                                                                     Oueslati

          Ichkeul and Bhiret el Biban Lagoons, which would be drastically altered by sea
          level rise. Along the Gulf of Gabes (particularly Jerba and Kerkna Islands)
          fishing is still conducted by the traditional method of using palm fronds stuck
          into tidal flats to traplfish brought in by tidal currents; along other parts of
          the gulf, many families feed or support themselves by gathering cockles in the
          tidal flats.     But sea level rise would inundate most of the tidal flats.
          Breeding facilities for fish (Monastir), oysters (Lagoon of Bizerte) and other
          shellfish would also be at risk.

               Finally, we could expect the erosion and loss of a major portion of the many
          archeological sites that are among the most important constituents of Tunisian
          culture.



          RESPONSES

               Like other nations discussed in this report, Tunisia could respond to sea
          level rise either by holding back the sea or by retreating landward. Most of the
          structural approaches described by Pope (Adaptive Options, Volume 1) would be
          appropriate for some part of the coast, and in many cases, the necessary
          structures would not have to be erected for several decades.         By contrast,
          although shores will retreat and settlements will be relocated in many (if not
          most) parts of the coast, the anticipatory strategies presented by Titus
          (Adaptive Options, Volume 1) would be difficult to implement, because they
          presuppose that (1) officials are willing to modify current activities to protect
          against crises not likely to occur for several decades, and (2) that
          environmental protection is sometimes important enough to prohibit construction.
          Neither of these assumptions yet applies to coastal management in Tunisia.

               The inhabitants of the coast are somewhat aware that erosion and
          salinization threaten their fields and dwellings, but they generally are not
          aware that rising sea level is causing the problem.       Similarly, it would be
          obvious to mudflat fishermen that if sea level rise inundated the flats, their
          livelihood would be threatened.      Because their ancestors have pursued this
          traditional occupation for centuries, the fact that the crisis would confront
          their grandchildren (instead of them) would not substantially reduce their
          concern. But no one has informed them about this problem.

               Currently, only two state agencies are even concerned about current beach
          erosion problems.   Although they have tried solutions, the projects have been
          arbitrary, scattered, and poorly studied. They have been mostly ineffective and
          in some cases have made the problems worse. Managers almost never consider the
          relationship between sea level rise and current problems. There is a complete
          lack of legislation and policies to protect the coastal environment.           When
          coastal areas are developed, no one is considering the argument by Everett
          (Environmental Implications, Volume    1) that in the long run, a hectare of
          mudflats might feed more people than a hectare of agricultural land, and that we
          should therefore set development back farther from the shore.



                                                 215











              Mediterranean


              THE COASTAL GEONORPHOLOGY

              Cliffs

                  The most important and extensive active cliffs are     characteristic of the
              northern coasts (characterized by relatively deep water    and exposed to strong
              northern and northwestern swell) of the country where they generally average
              15-30 m in height. In rare contrast, such as at the extremity of the Cap Bon
              peninsula, they are higher than 50 m.

                  For the most part, these cliffs consist of sandstone and clay and rarely are
              composed of rocks, limestone, or marls.     Rocky cliffs (eolianites and marine
              quaternary limestones) that alternate with fluvial layers often show remarkable
              differential erosion rates. However, such cliffs are usually only a few meters
              high (5-10 m).

                  Along the entire northern coast, the cliffs are retreating, sometimes quite
              rapidly, under the attack of north and northwesterly swells. Measurements taken
              during 1982-87 on cliffs 7 to 15 m high, formed in the Numidian flysch, showed
              them retreating at rates varying from 1.5 to 8 m/yr. Because of the very humid
              atmosphere and steep coastal slopes, landslides are frequent wherever clays
              dominate. . Landslides along the northern coasts are also threatening human
              dwellings. Fortunately, this area is not yet densely occupied.

                  There are fewer eroding cliffs on the eastern coasts. For the most part,
              they are a few meters (2-5 m) high and are formed in Pleistocene materials
              (especially alluvium, eolianite, and marine limestone).       The only important
              cliffs there are along the Gulf of Gabes and its surroundings, where they are
              formed in gypsum-rich clays covered by a strong calcrete (attributed to the lower
              Quaternary) or a gypsum crest (late Pleistocene). These latter cliffs, generally
              averaging 7 to 15 m in height, are sometimes -prone to high rates of erosion,
              despite the small waves. There is severe erosion of the important archeological
              sites that are visible in the upper part of the cliffs (e.g., on western coast
              of the Kerkna archipelago and at Nadhour between Sfax and Gabes Town).

              Unconsolidated Low Coasts

                  Unconsolidated low coasts are extensive in Tunisia and are found primarily
              at the inland margin of wide gulfs (Tunis, Hammamet, Gabes) and bays (Tabarka and
              Bizerte).   They are especially developed and predominant along the eastern
              portion of the coastal landscape.    They generally consist of alluvial plains
              formed by fine material dating back to the late Quaternary, mainly the Holocene
              and the historic'times. The seaward margin of these lowlands is characterized
              by sandy beaches, small cliffs, or salt marshes. These are found in the Gulf
              of Gabes and its surroundings where tides are high and may reach 2 m at spring
              tides.

                  Careful observations reveal significant regional differences in these
              lowlands because*of physical conditions, human activities, and the orientation
              of the coast. This section describes several distinctions:

                                                     216











                                                                                     Oueslati

                  A narrow alluvial plain situated at the inland portion of a bay bordered
                  by sizable cliffs and intersected by smgll but active wadis.            The
                  shoreline is characterized by a large sandy beach favoring the formation
                  of extensive dunefields and imgortant human settlements inland.

               This is the case of the Tabarka and Zwaraa coasts, which are situated near
          the Algerian border. The plain, averaging 4 m in height, is made of sand and
          clay sometimes containing more or less well-rounded pebbles. It covers about
          5 km' and is partly occupied by the Tabarka agglomeration.

               This area boasts one of the best sandy beaches of the country. Extending
          over 10 km, this beach stretches to 50-70 m in width, especially around the mouth
          of wadis.   It benefits from two important sources of sediments:    (1) wadis that
          cross in their higher courses steep slopes formed in the Numidian flysch, and (2)
          rocky active cliffs situated at the borders of Tabanka Bay. Well exposed to the
          ambient winds, this beach formed an important source of sand to be blown inland
          to create an extensive and thick dunefield (Ouchtata field) that is today largely
          stabilized by a planted forest.      The system must have been repeated in the
          geologic past, because recent dunes cover Pleistocene eolianite. The assemblage
          of forms is crossed by active wadis that in turn supply the shoreline with sand.

                  A narrow, largely alleviated plgin. occupying the inner margin of a bay
                  and devoid of active wadis.    The shoreline is also characterized by a
                  sandy beach favoring the formation of large dunes.

               In Bizerte, situated on the northern coast, the plain is 200-700 m wide and
          covers about 3.5 kM2.   Its altitude, which rarely exceeds 10 m above sea level,
          is sometimes lower than 2 m. This is especially the case in the outer section,
          which is often characterized by a swampy landscape.         Sediments are mainly
          composed of sand and silt, except in the northern part where clay predominates.
          The sediments are locally quite thin (50 cm-1.5 m) and cover marine consolidated
          deposits inherited from the Tyrrhenian stage. The beach covers about 12 km. At
          its eastern part, well exposed to the northwest winds, is a large field of sand
          dunes (Rmel's field), now almost wholly colonized by a planted forest.

                  A wide deltaic plan formed by a large wadi and situated in a gulf. The
                  shoreline of this plain is characterized by sandy beaches and lagoons.

               The deltaic plain of the Medjerda, the largest and most important river of
          the country, covers about 600 kM2.   It is generally 1-10 m above sea level, but
          in some parts it may be less than 30 cm above sea level.        Its sediments are
          mainly composed of sand and clay. Swamps occupied a very large portion of the
          area before the draining operations undertaken since the French colonization.
          Today the swamps are found only in the lowest section of the delta, especially
          near the shore.

               The formation of this deltaic plain dates back mainly to the Holocene. But
          its progradation was significant during historic times because of the increased
          sediment carried by the river following deforestation. The ancient archeological


                                                  217











              Mediterranean

              site of Utica illustrates such a history of alluviation. This site is today more
              than 10 km inland, whereas it was a harbor in ancient times.

                   The coast is characterized by a relatively wide (10-15 m) sandy      beach and
              a low (2-3 m) and narrow (30-60 m) foredune. The northern part shows      a typical
              spit at the location of a former mouth of the Medjerda River, which was    abandoned
              following the 1973 flood when the river shifted southward to occupy an artificial
              channel originally designed to drain the excess water during floods.             The
              southern part of the coast is well exposed to the northwestern winds, which
              favored the formation of a dunefield (Raoued Gammarth) now almost entirely
              wooded.   The coast is also characterized by a lagoonal landscape (see the
              paragraph describing lagoons).

                      An alluvial plain at the mouth of a major river and situated at the
                      inland margin of a deep bay.     The coast is characterized by a densely
                      occupied sandy beach.

                   This is the case of the coast of the bay of Tunis, which is largely occupied
              by the southern suburbs of Tunis, the capital of the country. The alluvial plain
              is an accumulation mainly of the Miliane wadi, Tunisia's second largest river.
              Relatively wide (approximately 36 km) and low (2-10 m), this coastal plain was
              created essentially during historic times because its material covers marine
              deposits dated from about 2,750 years ago and certain antique ceramics.          The
              alluvial deposits are generally fine (sand and clay), but can locally contain
              some coarse layers of mixed and more or less well-rounded pebbles.

                   The beach is about 10 m wide and is generally accompanied by a small
              foredune (1-2 m high and 10-30 m wide). Dunes are much more prevalent on Tunis's
              eastern coast than on its northern coast. An example is the small dunefield of
              Borj Cedria-Soliman, which is partly covered by a planted forest.         The land
              immediately behind the foredune, is almost everywhere, swampy and colonized by
              salt plants.
                      A straight coast with @ctive streams, narrow alluvial glain, broad sandy
                      beaches, extensive dunefields. and absence of major human settlements.

                   These characteristics are prevalent along the coast between Wadi el Abdi and
              Wadi el Mgaiez on the northwestern face of the Cap Bon peninsula.        The plain,
              averaging 800 m wide and 5-10 m high, is limited landward by a dead cliff. Its
              deposits are generally made of sand and silt and often lie on a bedrock platform
              inherited from the Tyrrhenian transgression. This coastal type is prominent only
              around the mouth of wadis that in their higher and middle courses drain steep
              slopes across Miocene marls and sandstones. The beach is generally 10-15 m wide,
              but can stretch 50 m wide in some river mouths. The dune fields are sometimes
              very extensive and often cover late Quaternary eolianites.

                      An alluvial plain at an inland margin of a large gulf intersected by
                      active wadis. The shore is characterized by a broad sandy beach, with
                      localized development, and a lagoonal landscape.


                                                      218











                                                                                       Oueslati

                This is the case of a large part of Hammamet Gulf, especially northern
           Hergla and southern Sousse.    The plain covers about 150 km'; its height varies
           from 2 to 10 m. The seaward parts of the coast are often swampy and saline.
           The beach is generally well developed, stretching into 40 m wide in many places.
           But foredunes are large in only two cases:       in Skanes and between Hergla and
           Selloum, where it is largely wooded.       Lagoons characterize segments of the
           northern Hergla and southern Sousse coasts. Except for the area between Hergla
           and Bou Ficha, the Hammamet Gulf coast has been subjected to extensive human
           development, particularly hotel construction in Hammamet, Monastir, and
           especially Sousse.

                   A relatively straight coast devoid of active wadis and characterized by
                   a narrow coastal plain and wide sandy beach.       The human installations
                   vary from one region to another.

                In four main regions -- Mahdia, Chebba, northeast Jerba, and Zarzis -- the
           coastal plain is sometimes only a few hundred meters wide. Its altitude may be,
           such as at Mahdia, less than 3 m above sea level, where there is extensive
           swampland.    Generally this plain is situated downdrift from a consolidated
           coastal barrier or a dead cliff dating back to the Tyrrhenian stage.

                At Mahdia the beach is about 10-15 m wide, and the foredune is always small
           (2-3 m high) and discontinuous. The coast is partly developed, especially in the
           segment next to the city of Mahdia (residences, industries, and hotels).          At
           Chebba the beach is wider and is sometimes punctuated by Pliocene sandstone
           outcrops. It is also has an extensive dunefield inland, now artificially fixed,
           and the coast is still unoccupied.

                The beach of Jerba, extending almost 20 km, is frequently wide (7-20 m) and
           is also punctuated by rocky outcrops (marine limestones, eolianites, and
           calcretes). It is not continuous, forming elongated spits at three sites. The
           foredune is locally well developed. Sand dunes, sometimes covering large areas
           are often occupied by orchards and dwellings. The major part of this coast is
           occupied by hotels often built close to the shoreline.

                At Zarzis, the coast is largely developed, especially with tourist
           facilities. The beach resembles that of Jerba in its width and its outcrops of
           rocky material. But the foredune is relatively smaller.

                   A coast marked by a sebkha landscape fringed by a microcliff or a sandy
                   6-each, especially at the mouth of active wadis.

                These characteristics predominate along a large part of the coast of the
           Gulf of Gabes. The lowlands, composed mainly of fine sandy and silty materials,
           are generally 5-10 m high. The most important of them are linked to relatively
           large wadis and are 2-10 km wide. In some cases, such as at Kerkna and Jerba,
           the sandy and silty material is thin (50 cm-1 m) and covers a marine limestone
           dating back to the Tyrrhenian.



                                                   219










              Mediterranean

                   Sebkhas', salt marshes found in northern Africa, are a major feature of the
              coastline. The largest sebkhas are inherited from Holocene eustatic.sea level
              oscillations and occupy the position of ancient lagoons or bays that have been
              filled by continental deposits.

                   Beaches occupying the mouth of wadis are relatively wide (10-20 m) and are
              accompanied by small (2-5 m) but sometimes well-defined foredunes. In s     *ome cases
              the beach forms a spit.      Except for the coasts at Gabes and Chaffar, these
              beaches are still unoccupied.

              Wetlands,

                   Wetlands occupy the seaward parts of the alluvial plains (Medjeida, Miliane,
              Gulf of Hammamet, Mahdia) and can be associated with sebkhas. The'most important
              wetlands exist along the southern coast (Gulf of Gabes and its surroundings) and
              correspond to typical tidal marshes favored by the low energy of the coast and
              the high tides. Such tidal marshes occupy different positions (behind spits and
              capes, bottoms of creeks, mouths of wadis) and have a low vegetation dominated
              by Salicornia.   They also present some particularities in comparison to tidal
              marshes of other climate zones. They are always characterized by the existence
              of dunes and plants adapted to the aridity, and they often extend landward into
              the sebkhas and alluvial plains.

              Lagoons
                   Lagoons are numero.us and varied along the Tunisian coasts. gut according
              to their morphology, hydrology, and position in comparison with the sea, they can
              be classified into two main categories:          (1) wide lagoons. with   , continued
              communication with the sea and (2) those isolated from the sea with a sandy bar,
              and lagoons invaded only during the stormy season.

                   Four main lagoons belong to the first category:

                   *  The Lagoon of Bizerte covers about 15,000 ha and connects         to the sea
                      through a large channel, now partly developed.

                   *  The Lagoon of Ichkeul (12,000 ha) is linked to the Bizerte Lagoon through
                      the Tinga emissary and responds to an important seasonal variation. It
                      is occupied by marine water only during the dry season. In the winter
                      it is the recipient of considerable continental discharge because of the
                      large wadis that divert into it.

                   * The Lagoons of Ghar el Melah (3,000 ha) and Tunis (4,000 ha) are cut off
                      from the sea by a sandy coastal bar, but connected to the sea by dredged
                      inlets.



                'An arabic term for a flat area, close to the water table and characterized
              by a salt material.

                                                       220











                                                                                    Oueslati

                  The Lagoon of Bhiref el Bibane, situated near the Libyan border, has a
                  surface of about 30,000 ha.    It is bordered on the seaward side by a
                  consolidated littoral bar dating back to the Tyrrhenian. Connection with
                  the sea is possible through some natural inlets, among which the inlet
                  of S. Mohamed Chaouth is the most important.

               Lagoons of the second category are connected to the sea only through natural
          inlets that generally open only during storms. These lagoons are numerous and
          exist in the Gulf of Tunis (St. Sidi Bakhoun, St. Ariana), in the eastern coast
          of the Cap Bon peninsula (St. Bouzid, St. Klibia), in the Gulf of Hammamet (St.
          Assa Jiriba, St. Halk el Mungil), and in the Sahel (St. Skanes, St. Dimass).

               In all of these situations, the inland area is often swampy. The salinity
          of the lagoons and the temperatures are often higher than in the open sea. They
          also increase toward the south. In the Bhiret el Bibane Lagoon, for instance,
          the temperature can climb as high as 40*C, and the salinity increases in the
          summer when sirocco winds blow.



          CONCLUSION

               Given our inability to effectively address problems due to current relative
          sea level rise, one might pessimistically assume that coping effectively with
          accelerated sea level rise will be close to impossible.      But there may be a
          positive aspect: As late as 1983, for example, the United States was failing to
          address current trends of sea level rise, but widespread public attention to the
          greenhouse effect prompted officials to look into the issue of sea level rise and
          to direct their staffs to at least take current trends into account. As the
          paper by Klarin and Hershman (Legal and Institutional Implications, Volume 1)
          illustrates, five years later officials were preparing for an accelerated rise.
          The same thing could happen here.     In Tunisia, there is sufficient technical
          expertise to begin preparing for a rise in sea level, but neither the public
          awareness nor the official recognition necessary to start the process.

















                                                 221











               Mediterranean

                       APPENDIX: ADDITIONAL DETAILS ON THE CLINATE OF COASTAL TUNISIA


                    Some very important regional differences can be observed between the
               northern and the eastern coasts, particularly in the rainfall volume and wind
               characteristics.    The mean annual rainfall is often higher than 500 mm and
               sometimes reaches I m in the northern coast, whereas it is generally less that
               300 mm in the major part of the eastern coast.         Moreover, the rain average
               diminishes rapidly toward the south. Near the Libyan border it is only about 100-
               150 mm/yr. Rain is often torrential and falls in concentrated patterns of a few
               days.

                    During the summer, the mean monthly temperature everywhere is greater than
               20*C.  The average daily maximum temperature during July and August is always
               higher than 30% and can reach 400C when southern winds, the sirocco, are
               prevailing.    During the winter, the mean temperature of the coldest month
               (January) is higher than 100C almost everywhere along the coast.            The mean
               minimum temperature generally oscillates between 6* and 8*C. Temperatures are
               rarely below OOC.

                    The strongest and most frequent winds generally blow from the northwestern
               direction and occur mainly in winter. Nevertheless, differences exist according.
               to seasons and the coastline orientation. On the northern coast, western and
               northwestern winds prevail occurring approximately 35% of the time.           On the
               eastern and especially on the southern coasts, the gentler eastern and
               northeastern winds dominate.

                    The contrast between the northern and the eastern coasts of Tunisia appears
               also in the hydrodynamic and the marine water characteristics. Because of its
               exposure to northern winds and its relatively deep water, the northern coast has
               cooler, less saline, and rougher and larger waters than the eastern coast. At
               the end of the hot season, water temperatures are about 21-220C, and the salinity
               is about 37 0/00 (parts per thousand).           At the end of the winter, the
               temperatures vary between 15 and 160C, but the salinity is still almost unaltered
               (36 to 37 0/00) except in the inner portion of the Gulf of Tunis. Unless there
               is an exceptional storm, wave height along the northern coast rarely exceeds 6
               m. In the Gulf of Tunis, waves of 1.5 m and higher represent only 6% of the
               observed cases. Tides constitute a secondary phenomenon as their range is, at
               spring tides, about 0.20 to 0.30 m.

                    Along the eastern coats, waves are mainly generated by the eastern and the
               northeastern winds. They are generally characterized by a low energy. The most
               important waves rarely exceed 1.20 m in height. From 1954 to 1961, the largest
               wave registered at Sousse was only 3.5 m in height. The eastern coasts have a
               broad shelf.   The southern part (Gulf of Gabes) is characterized by important
               tides. Here, the tidal range is often higher than 0.70 m and may reach 2 m at
               spring tides. Water temperatures of the eastern coasts are always more than 160C
               and increase southward, where they are about 16-190C and 220C, respectively, at
               the end of winter and summer. However, the salinity change is less perceptible
               -- 37.1 and 37.2 0/00, respectively, at the end of the cool and the hot seasons.

                                                       222











                                                                                 Oueslati

        ACKNOWLEDGENENTS

             The author is greatly indebted to Prof. R. Paskoff and Prof. N. Psuty for
        their help.    J. Titus has revised and improved the text and proposed some
        modifications in the English text. All of them are sincerely acknowledged.


        BIBLIOGRAPHY

        Oueslati, A. 1986. Jerba et Kerkna (iles de la cote orientale de la Tunisie):
        leur evolution geomorphologique au cours du quaternaire. Publ . Univ. Tunis, 210
        P.

        Oueslati, A., R. Paskoff, H. Slim, and P. Trousset. 1987. Deplacements de la
        ligne de rivage en Tunisie d'aprea les donnees de l'archeologie a 1'epoque
        historique. Coll. Intern. C.N.R.S. Paris, 67-85.

        Oueslati, A. 1989. Les cotes de la Tunisie, recherches geomorphologiques. Th.
        d'Btat, University of Tunis, 680 p.

        Paskoff, R. 1985. Les plages de Tunisie. BDITEC, Caen. 198 p.

        Paskoff, R., and A. Oueslati. Modifications of coastal conditions in the gulf
        of Cabes (southern Tunisia) since classical antiquity. In: Journal of Coastal
        Research (in press).

        Pirazzoli, P.A. 1986. Secular trends of relative sea level (R.S.L.) changes
        indicated by tide gauge record. In: Journal of Coastal Research, Special Issue
        1:1-26.


























                                               223












            RESPONSES TO THE IMPACTS OF GREENHOUSE-INDUCED
                              SEA LEVEL RISE ON EGYPT



                                          M. EL-RAEY
                          Department of Environmental Studies
                                 University of Alexandria
                                      Al exandri a, Egypt





        ABSTRACT

             The projected sea level rise of I meter in the next century from greenhouse-
        induced global warming is a serious concern to deltaic countries such as Egypt.
        Deltas are particularly susceptible to sea level rise because the delicate
        balance at the river-ocean interface produces land that is inherently just above
        sea level. Deltas depend on new sediment delivered by rivers to enable them to
        keep pace with sea level rise.      Sea level rise will exacerbate the erosion
        already present in the Nile River delta caused by dams upstream that have reduced
        the sediment supply.

             The population of Egypt is clustered along the banks of the Nile River and
        within the delta.   Only 3.5% of the one million square kilometer area of the
        country is cultivated and settled (Quarterly Economic Review of Egypt, 1985).
        The nation's coastline has experienced severe erosion in the last 100 years.
        Reduction in the supply of sediment to the delta started with the construction
        of delta barrages in 1881. Since then, the situation has become progressively
        worse with construction of new dams. The 1964 construction of the Aswan High
        Dam has completely stopped the supply of sediment to the delta; since that
        time, many areas on the delta coast have been eroding I meter every year.        In
        some areas, erosion rates have jumped to more than 100 meters per year.

             The impacts of global warming on the Nile delta are taken seriously by
        concerned authorities in Egypt.    A basic survey of available information and
        implications has been compiled by Broadus et al. (1986) and Sestini (1989).
        Sestini and others anticipated that a relative rise of I meter could submerge
        lowlands 30 km inland of the coast or more, which accounts for 12-15% of Egypt's
        arable land, 8 million people, and 10:-15% of the country's gross national
        product.     Salt intrusion will also contaminate water used for drinking
        and agricultural purposes.    Many people have called for a national policy of
        response to these anticipated changes.


                                               225











               Mediterranean

                    Responding to sea level rise in Egypt will be difficult because most of
               the arable land is along the Nile River or within the Nile delta. Therefore, when
               this area becomes uninhabitable, moving to higher ground will not solve all the
               problems, because this land will be inadequate for growing enough food to support
               the displaced population. Other possible responses include building a dike along
               the delta coastline or bypassing sediment around Aswan High Dam.       This study
               investigates the impacts of a 1-meter sea level rise on Egypt, assesses what is
               at risk along Egypt's coastline, and discusses possible responses.


               INTRODUCTION

                    Technological developments and the conversion of agricultural communities to
               industrial communities have resulted in excessive use of energy resources. As
               energy use is necessarily associated with waste in the form of materials and
               heat, this waste has increased dramatically in the last few decades to the extent
               that it has become a major threat to the environment.    In particular, a gradual
               increase of greenhouse gases (CO,, CFCs, 031 CH,, and OH) in the environment has
               resulted in a measurable warming of the atmosphere with anticipated changes in
               climate,  and additional     effects such as sea level rise and changes          in
               precipitation patterns.

                    The impact of these climate changes on the ecosystem, human activities,
               health, and welfare should be carefully assessed before a policy for
               countering those impacts is developed. National and international organizations
               have coordinated efforts to develop measures to adapt to these climate changes.

                    Models have predicted that the temperature rise associatedwith accumulation
               of greenhouse gases may range from 2.50C to 50C by the middle of the
               next century.   The associated rise in sea level, due to both ocean thermal
               expansion and melting of polar glaciers and ice caps, is anticipated to range
               from 30 cm to 150 cm (Titus, 1986; UNEP, 1987, 1989).

                    Egypt's Nile delta, in particular, will be adversely affected because its
               northern region is entirely less than 1 meter above sea level. It is already
               subject to a great deal of environmental changes due to severe reduction of
               sediment delivery after construction of the Aswan High Dam.

                    This paper outlines the impact of various environmental changes over the
               northern Egyptian coasts, directs attention to areas of potential risk from the
               effects of climate change, and recommends a policy by which government agencies
               could reduce losses and help Egypt adapt to global warming.


               IMPACTS ON THE NORTH COAST OF EGYPT

                    No formal multidisciplinary team has investigated the detailed impacts of
               climate change on the Egyptian delta. However, a number of research centers have
               studied one aspect or another of the problem and have accumulated valuable
               information.    These groups include the Institute of Coastal Research, the

                                                      226










                                                                                  E7 -Raey

         Institute of Oceanography, the Suez Canal Authority, the Environment Affairs
         Authority,a nd the University of Alexandria research groups. A number of United
         Nations Environment Programme meetings have also stressed the seriousness of the
         impact of global warming, especially sea level rise.

              An assessment of the impacts of climate changes on the northern Egyptian
         coasts requires the documentation of detailed information on land use,
         topographic variations, population distribution, soil characteristics, coastal
         erosion, and socioeconomic distribution parameters.         Unfortunately, the
         information already available is outdated, intermittent, and, in many cases,
         inconsistent. In addition, large uncertainties exist regarding the accuracy of
         important variables, such as regional subsidence rates, elevation, and the
         distribution of economic activities.      Nevertheless, available information
         provides a general account of the likely impacts.

              A I-meter interval elevation contour map of the Nile Delta and vicinity
         (Figure 1) shows that the area below the 1-meter contour extends inland as much
         as 30 km south of Alexandria city and south of Lake Manzala (Sestini, 1987).
         Because about 40% of Egyptian industry is located near and around Alexandria,
         we can infer that serious damage could result from a I-meter rise in sea level.
         In addition, because of the sandy and porous nature of the soil in this area,
         waterlogging resulting from saltwater intrusion may affect the fertility of the
         arable land below the 2-meter or perhaps the 3-meter contour. Considering the
         relatively high population density and extensive resources of the area, a
         tremendous socioeconomic impact would be likely.

              Recent analysis of erosion and accretion patterns (Frihy et al., 1989) has
         also shown large changes over the northern Egyptian coasts. Hence, many tourist,
         recreational, and economic sites will be subjected to considerable stress. In
         addition, this area is generally subsiding.     Based on these results and on
         consideration of economic development axes in both vertical and horizontal
         directions on the north coast (ARICON, 1988), we conclude that sea level rise
         will pose major risks to three areas: the Alexandria region west of the Rosetta
         branch, Lake Burullus and vicinity, and the Lake Manzala region.

              1.  Alexandria rgqjo: The region at risk includes residential areas in
                  several localities, in addition to industrial sections west and east
                  of the city.    A large part of the area south of Alexandria city
                  (Amerya) is also below the I-m contour level.         These areas are
                  presently under extensive development. Plans for development-in this
                  area should be carefully revised.        Some tourist sites west of
                  Alexandria are also built between the    first ridge and the sea (at
                  localities below the I-meter contour), which puts them at risk. This
                  region hosts about 40% of Egypt's industry, as well as many historical
                  and tourist sites.

              2.  Lake Burullus:   This area is already subject to serious erosion and
                  accretion problems.    Rising sea level will increase this rate and
                  destroy beaches and resort villages in the area. In addition, the lake
                  is under consideration for a water storage project. The environmental

                                               227











                 Mediterranean







                                                  UEDITER RAN EAN SEA



                                                   BALTIM

                                    ROSETTA                                DAMIETTA




                                                                                                 PORT SAID
           ALEXANDRIA                                               2

                                                                                                                               BARDAWIL
                                                                                                           TINEH



                                                   NILE RIVER
                                                  ROSETTA
                                                  BRANCH
                                    s
                                10                                                                                   S I N A I
                                                       ti TANTA     NILE RIVE              5
                                                                    DAMIETT,
                                                                    BRANCH
                                                        to
                                                                                                      ISMAILIA
                                                                                          20



                       N I L E D E L T A                                                               F7_1 Wetlands (0 rn above sea level)
                                                                                                       L@J

                                                                                                           Sand dunes. average heights
                              0     Is  30                                                                 2 to 10m above sea level
                                                                 CARIO
                                   km



                 Figure 1.       Contour map of the Nile delta and vicinity (Sestini, 1989).                                  In
                 addition to     inundating land below 1-meter elevation, a 1-meter rise in sea level
                 would waterlog land up to 2 and possibly 3 meters.


                              impact assessment of this project should take sea level rise into
                              consideration.

                       3.     Lake Manzala region: The area at risk is extensive and includes the
                              cities of Damietta and Port-Said, and extends south of Lake Manzala
                              to include a large part of the Suez Canal on both sides.                             This area
                              hosts a large harbor at Damietta in addition to many fishing and
                              industrial centers.

                       A question may also arise here on the discharges of the Nile River necessary
                 to counter the effects of sea level rise at the promontories.                               Although such
                 discharges would assist land creation, they would adversely affect bridges,
                 water supply, and perhaps some land along the Nile.

                                                                      228










                                                                                    EI-Raey

              A detailed quantitative environmental impact assessment should be carried
         out based on use of geographical information systems, making use of the
         information on the northern coasts already existing at the University of
         Alexandria and other research centers.     A multistage technique in which the
         impact could be calculated by an interaction matrix for each 0.25 meter of sea
         level rise is suggested. An interaction matrix with elements of the "magnitude"
         and "importance" of the impact should be calculated for each area. The elements
         of such a matrix could be estimated from accurate analysis of geographic
         information systems based on recent data of the area.


         ADAPTIVE OPTIONS

              If sea level rises, Egypt has only three options:

              ï¿½    Withdraw from coastal areas;

              ï¿½    Build walls around limited areas to protect valuable lowlands or
                   industrial complexes from inundation; or

              ï¿½    Adjust to expected changes, and perhaps take advantage of them by
                   appropriately changing land use (e.g., shifting to crops that tolerate
                   flooding).

              Because of the variable environmental and economic conditions in the
         vulnerable areas, the choice of any of these options will greatly depend on the
         area under consideration.     A detailed study of each area is, therefore,
         necessary.

              Alexandria city is built over a number of relatively high hills or dunes
         separated by narrow "tunnels" (Figure 2).     It may be possible to protect the
         urban and industrial areas against rising seas by building a number of walls
         to protect the southern parts of the city. However, such a response must await
         accurate analysis of data and studies of geological structure and elevation of
         these hills.

              In general, any policy that would be of interest for future development in
         the area must be of the type that will help whether or not climate changes --
         i.e., it must a two-sided policy.    Conserving energy and water resources and
         converting to salt-tolerant agriculture are policies of this type.         Broadly
         speaking, response strategies fall into two categories: limiting global warming
         and adapting to its consequences.

         Limiting Global Warming

              This approach is intended mainly to buy time:

              1.   Limit the production and emission of C02, CFCs, and other greenhouse
                   gases. Enforce air pollution control measures. Apply the Clean Air


                                                229











                          Mediterranean




                                                                                                 29-150'                                       30-1
                                   Alexandrla Topography                                                                                                           Abu-Qir


                                   Hills or Dunes                                                                                                                    Abu-Oir Gulf
                                   Delta Deposits                                                                                    Al-Montazah
                                   Present Borders of Lake Mariut                         MEDITERRANEAN SEA
                                   Regions From Lake Marlul That
                                   Have Been Drained

                                          0   2   4    6
                                               krn                                                           East Harbor
                                              290 40'                                                Qayetbaj
                                                                                                      Citadel

                                                                                          Raas-EI-Teen                                                                         N
                                                                                Alexandria Harbor

                                                                                    Breakwater
                        310
                        10,


                                                                 Raas-El-Agami      Sea Gulf                Lake Marlut

                                                                                                                                                   Abis Area
                                                                                                                                                                    Kafr-El-Dawar



                                      Madut Valley                                                sop                                A/
                         AI-Mex-Abu-Sir Dunes

                         Om-Gaghyu Island

                                                                                              Mariut Plains



                                          0
                                    .0 ,        /-?                           A]-Amereya aq@,so,

                         Figure 2. Alexandria outskirts showing ridges over which the city is built.


                                           Act in Cairo, Alexandria, and Tanta, at least, and enforce it by
                                           efficient monitoring networks.

                                   2.      Develop and enforce the operation of more energy-efficient engines.
                                           Increasing engine efficiency is found to be one of the most important
                                           factors in reducing greenhouse emissions (Lashof and Tirpak, 1989).
                                           Include a social impact tax in the price of polluting fuels to limit
                                           their excessive use.

                                   3.      Work on planting greenbelts, and increase the awareness and perception
                                           of the public concerning overuse of fertilizers. Encourage and support
                                           programs for environmental education and research;

                                   4.      Increase the proportion of solar energy use and/or other renewable
                                           energy sources, such as wind energy.                                       Support programs for studying
                                           and implementing energy conservation techniques.

                                                                                                 230










                                                                                       EI-Raey

          Adaptation

                Adapting to global warming involves long-range planning.       For instance,
          one of the most important problems developing countries are expected to face in
          the near future, with special reference to Egypt, is the availability of
          freshwater.   With a population growth rate of 2.89ol per year, future domestic
          water use is expected to consume a large part of Egypt's fixed water budget
          (55 million cubic meters per year). In view of the projected global warming,
          water conservation programs must start -- the sooner the better -- whether we
          have climate changes or not. Other adaptation policies for Egypt include the
          following:

                1.   Adopting new agricultural practices with improved efficiencies for
                     using freshwater resources.

                2.   Encouraging and developing multidisciplinary institutions concerned
                     with the reallocation and use of scarce freshwater supplies, such as
                     groundwater resources. Developing techniques for rainfed (as opposed
                     to irrigated) agriculture. Supporting projects based on rainfall along
                     the north coast.

                3.   Strengthening mechanisms for converting land and other resources into
                     and out of agriculture in response to climate change.

                4.   Adopting a new policy for urban development of coastal regions based
                     on predicted sea level rise for the next 40 or 50 years. For instance,
                     resort villages with massive foundations are currently built on ridges
                     parallel to the shore. In the future, only transportable wooden cabins
                     should be allowed near shores.

                Special policy recommendations for the northern coastal region include the
          following:

                1.   Plans for building an international road along the north coast consider
                     enforcing road foundations to act as a wall for protecting the Nile
                     delta in case of sea level rise.       The same could be extended to
                     vulnerable areas west of Alexandria.

                2.   Reevaluate the Alexandria and Damietta master plans, based on new
                     predictions. Build future massive beach resorts on the ridges at least
                     I meter above sea level.

                3.   Launch a socioeconomic program directed toward increasing public
                     awareness  that   rainfall    patterns   may   change.      Use    recent
                     biotechnological capabilities of saltwater-tolerant plants.

                4.   Develop and implement techniques for reducing water table levels over
                     existing lowlands and human settlements near the coastal regions.
                     Develop windmill techniques of water pumping, and test capabilities
                     in pumping already waterlogged areas in Agamy west of Alexandria.

                                                  231











                Mediterranean

                     5.   Control the overexploitation of quarries along the coasts west of
                          Alexandria.

                     6.   Relocate waste dumping to suitable sites to reduce future risk of water
                          pollution.,

                     7.   Investigate the technical and economic possibilities of protecting
                          Alexandria city by building a number of discontinuous walls over
                          "tunnels," and using local natural rocks, such as granite, basalt,
                          dolomite, and diorite.

                     8.   Delineate and study regions of erosion and accretion for better
                          evaluation of conditions along the northern coasts and identification
                          of areas most vulnerable to sea level rise.

                     9.   Encourage the reclamation projects to take place in areas with greater
                          elevation. Extend public services to newly developing communities in
                          the highlands, giving first priority to people from vulnerable areas
                          to move to these newly developed lands.

                    10.   Explore the technical and economic feasibility and impact assessment
                          of bypassing Nile River sediments from Aswan High Dam.

                     As a first step, a multidisciplinary team of experts should be formed to
                carry out a detailed environmental impact assessment of the effects of sea level
                rise and to recommend specific measures to counter these effects.            The same
                exercise should then be carried out for other effects of climate change.


                ACKNOWLEDGMENTS

                     The author acknowledges valuable discussions with Dr. S. Nasr from the
                Department of Environmental Studies, and with Dr. 0. Frihy from the Institute
                of Coastal Research.



                BIBLIOGRAPHY

                ARICON.      1988.    Master    plan   for   development     of   the   north     delta
                region and international road. Cairo, Egypt: Ministry of Reconstruction, New
                Communities and Infrastructure.

                Broadus, J., J. Millman, S. Edwards, D. Aubrey and F. Gable. 1986. Rising sea
                level and damming of rivers:     Possible effects in Egypt and Bangladesh.          In:
                Effects of Changes in Stratospheric Ozone and Global Climate, Vol 4: Sea Level
                Rise. J.G. Titus, ed. Washington, DC: U.S. Environmental Protection Agency and
                United Nations Environment Program.




                                                         232










                                                                                           El -Raey

           Frihy, O.E., S.M. Nasr, M.H. Ahmed, and M. EI-Raey.           Long term shoreline and
           bottom changes of the inner continental shelf off the Nile Delta, Egypt.
           (Submitted).

           Lashof, D.A., and D.A. Tirpak.       1989.   Policy Options for Stabilizing Global
           Climate. Washington, DC: U.S. Environmental Protection Agency.

           Quarterly Economic Review of Egypt.       1985.    Annual Supplement.     London:     The
           Economist Publications Ltd.

           Sestini, G.    1989.   The implications of climatic changes for the Nile Delta.
           Report WG 2/14. Nairobi, Kenya: United Nations Environment Program/OCA.

           UNEP.   1987.   United Nations Environment Program.       Environment Library No. 1.
           Geneva: United Nations Environment Program.

           UNIEP. 1989. United Nations Environment Program. The Full Range of Responses
           to Anticipated Climatic Change. Geneva: United Nations Environment Program.
           April.






























                                                     233











                       IMPACTS OF SEA LEVEL RISE ON PORTS AND
                        OTHER COASTAL DEVELOPMENT IN ALGERIA


                                         EL-HAFID TABET-AOUL
                                 Laboratorire d'Etudes Maritimes
                                    30 Rue Asselah Hocine Alger
                                           Algiers, Algeria





           INTRODUCTION

                More and more, the public is recognizing that global warming due to the
           "greenhouse effect" will increase the mass and volume of the water in the oceans
           and will thereby accelerate the rate of sea level rise during the next few
           decades. Such a rise would increase coastal erosion and other hazards of coastal
           life.

                Due to the seaward advance of deserts and rising sea level, the coastal
           zone of North Africa is becoming narrower. At the same time, population growth
           is causing rapid urbanization. Thus, it is important today to create strategies
           for adapting to the global warming of tomorrow.


           SEA LEVEL TRENDS IN THE MEDITERRANEAN SEA

                The Mediterranean shore has been populated since the beginning of recorded
           history. Ancient civilizations have left a great number of remains on the coast,
           which can be very helpful in addressing the impacts of sea level rise. As early
           as 1934, His Highness Prince Omar Toussoun ordered a study to determine how much
           the sea level had risen in the port of Alexandria, Egypt.

                Most people along the Mediterranean coast have not noticed the sea rising,
           but that does not mean it is not occurring. Tidal gauge records in Marseilles
           show that the sea level has been rising 1 mm per year there for the last century
           (Bruun, 1987). This rise may be limited by the region's climate. For example,
           the Mediterranean Sea is already an area of net evaporation, which tends to lower
           sea level. Moreover, seasonal variations may obscure the sea level. As Figure
           I shows, seasonal variations can be 100 times the annual rise.





                                                    235











               Mediterranean





                             E
                             E

                       -0-100

                          50

                        :t 0.0
                          50     IT I V1    1171      11111 @t@ I           I I
                          100    11111,11H.11111111111                      I- I , ,.
                                        1960     1965      1970      1975     1960

                                                        DATE


               Figure 1. Yearly evolution of mean sea level in Trieste, Italy, which is a good
               approximation of trends on the Algerian Coast.


               POSSIBLE IMPACTS ON ALGERIA

                    For Algeria, the most important problems resulting from sea level rise are
               likely to be the loss of usable land, damage to port facilities, and pollution
               of groundwater.

               Loss of Usable Land

                    The continental shelves in the western part of the Mediterranean Sea are
               rather narrow -- less than 25 miles wide -- and are cut by numerous canyons.
               Along the Moroccan and Algerian coasts, the shelf slopes an average of
               approximately 10%.

                    Above the sea, the limited width of the vital belt confined between the
               desert and the sea implies that national population growth will increase the
               urbanization of the coastal zone. In Algeria, more than 50% of the population
               lives within 50 kilometers of the sea (Figure 2).

                    Park et al. (1986) forecast that 40 to 75% of existing U.S. coastal wetlands
               could be lost by 2100. A similar impact can be expected in Algeria.

                      n
               Quays a d Port Facilities

                    Given the low tidal range (less than 50 cm) in the Mediterranean Sea, port
               facilities have been designed with levels close to sea level. In Algeria, ports
               are designed with quays up to 2.0 m above sea level. A rise in sea level would
               flood these structures as well as the operational land behind.

                                                      236











                                                                                                            Tabet-Aoul


                     Because of the importance of maritime trade, which represents more than
              90% of the total amount of the Algerian trade exchange, port designers should
              bear in mind the possible effects of sea level rise in future port construction.
              Fortunately, existing structures can be elevated as the sea rises.

              Groundwater Pollution

                     Most of the cities on the North African coast are supplied by groundwater.
              A rise in sea level will cause saltwater to contaminate the groundwater.
              Regarding soil permeability and smooth groundwater table slope near the shore,
              large quantities of freshwater will be lost, proportional to the rise in sea
              level.



              WHAT CAN BE DONE

                     Along the North African coast, both structural and planning measures will
              be necessary.

                     Rigid structures, such as breakwaters, seawalls, and groins, can protect
              urban areas.          However, given their high cost, these structures would be
              appropriate only where there are valuable buildings or land.                        If structures are
              destroyed by storms or other phenomena, they should not be rebuilt.

                                              MEDITERRANEE                   I&    Annaba
                                                               Chels
                                                        Ora                         na antine
                                                          0    .5..     satnao    0 T-Bbessa
                                                           Takemeen     'r,
                                                                       0o 06. s k


                                                        054kchar




                                                           -A -L & IF- It JE JIL




                                                            SAHARA
                                   @21PULATION
                                       0    1507241
                                        0   628S58
                                        0 305526
                                         0 107311

                                        2A   AV JWAW


                                    STATISTIOLIES 0. N-S N2 21   ALGERIA
              Figure 2. Algerian cities with more than 100,000 inhabitants.

                                                                  237











               Mediterranean

                     In rural areas, rigid solutions would not usually be justified economically.
               More flexible measures may be appropriate such as setback lines that prohibit
               construction in areas likely to be inundated within a specified period of time
               (up to 100 years). New construction criteria should be defined. However, the
               difficulty will be to convince officials to accept the loss of
               precious land today to prevent the consequences of something that will happen
               in the 21st century.


               BIBLIOGRAPHY

               Bruun, P. 1987. The effects of changing the atmosphere on the stability of sea
               level and shore stability. PIANC 58:129-132.

               Bruun, P. 1989. Coastal engineering and the use of the littoral zone. Ocean
               and Shoreline Management 12(5) and (6).

               Lamy, A., and C. Millot. 1981. Bottom pressure and sea level measures in the
               Gulf of Lions. Journal of Physical Oceanography 11:394-410.

               Park, R., T.V. Armentano and C.L. Cloonan.         1986.   Predicting the effects of
               sea level rise on coastal wetlands. In: Effects of Changes in Stratospheric
               Ozone and Global Climate.        Vol ume 4:     Sea Level Ri se.     J.G. Titus, ed.
               Washington, DC: United Nations Environment      Programme and the U.S. Environmental
               Protection Agency. October.

               Sharaf el Din, S.H., and Z.A. Moursy.         1977.   Tide and storm surges on the
               Egyptian Mediterranean coast. Rapp. Comm. Inter. Mer Medit. 24:2.

               Vignal, J.    1935.   Les changements du niveau moyen des mers le long des cotes
               en Mediterranee. Annales des Ponts et Chaussees 28.

               Weaver, D.F., and D.L. Hayes. 1989. Proposed response to sea level rise by a
               local government. In: Coastal Zone 189. New York: American Society of Civil
               Engineers, pp. 2490-2501.















                                                         238






















                NORTH AND WEST EUROPE











                THE VULNERABILITY OF EUROPEAN COASTAL LOWLANDS
                     ALONG THE NORTH SEA AND ATLANTIC COASTS
                                   TO A RISE IN SEA LEVEL


                                        DR. SASKIA JELGERSMA
                              Geological Survey of The Netherlands
                                              P.O. Box 157
                                2000 AD Haarlem, The Netherlands






          ABSTRACT

                The European coastal lowlands comprise deltas and plains including wetlands
          and natural areas at low altitudes that encompass extensive zones of densely
          populated, intense economic and agricultural activity. Around the southern North
          Sea Basin alone, the coastal plains area is the home of more than 200 million
          people who live close to present sea level and are already at risk from
          inundation as a consequence of coastal erosion, storm surge, and the current
          trend of sea level rise of I to 1.5 mm per year.

                During a session on the impact of a future rise in sea level, part of the
          European Workshop on Interrelated Bioclimatic and Land Use Changes, 12 papers
          presented case histories on the present situation of the shoreline.                  The
          consensus was that European coastal lowlands are already experiencing damage from
          erosion, inundation during storm surges, storm waves, subsidence, and saltwater
          intrusion as the consequence of sea level rise, increased incidence of
          storminess, and human activities.

                Moreover, many human activities are increasing the vulnerability of coastal
          areas to a ri se i n sea I evel .   These activities include sand extraction from
          beaches and offshore areas for reclamation and the construction industry; the
          destruction of natural shoreline defenses, such as sand dunes, to provide hotel
          accommodations and amenities for the tourist industry; the interruption and
          diversion of longshore sediment transport by groins, jetties, and harbors; the
          reduction of the sediment load of rivers by water management in drainage basins
          and the construction of dams and reservoirs, cutting sediment supply to nourish
          beaches and deltas; the canalization of rivers for navigational purposes; the
          reclamation of coastal lowlands for agricultural, industrialization, and
          residential development; and the extraction of groundwater for drinking water and
          irrigation, which has led to subsidence and the penetration of saltwater.



                                                    241









              North and West Europe

                   The maximum rise of sea level during the recent geological past did not
              exceed 2.2 m/100 years. During the past 4,000 years, when the rate of rise was
              considerably less, sedimentation has kept up with and locally exceeded sea level
              rise. In natural areas, where human activities are not pre-eminent, such as the
              Dutch, German, and Danish Wadden Sea, sedimentation has kept up with the present
              rise of sea level of 10 to 15 cm/100 years. Investigations of the sediments of
              the coastal lowlands indicate that, given a natural sediment budget, these areas
              responded and adjusted to a range of rates of sea level change and climatic
              change in the past.

                   The coastal lowlands of Europe have a good infrastructure.       Accordingly,
              they will be able to address future sea level rise more easily than countries
              that have none, e.g., the Third World.      Nevertheless, in both rich and poor
              nations, the socioeconomic impacts of a future sea level rise will be profound
              and widespread.


              INTRODUCTION

                   As the report of the Miami conference note      's, people have always been
              concentrated near the coast.        Although the general lack of topographic
              information has made it impossible  so far to estimate how many people live within
              one or two meters of sea level ,    we do know that about half of the world's
              population lives in deltas and other coastal lowlands. In most cases, deltas are
              entirely less than ten meters above sea level; and in many cases at least half
              the delta is within one or two meters of sea level.    Even for the portions with
              greater elevations, life is affected by sea level because the heights of river
              and storm surges are influenced by the base level of the sea.

                    For purposes of this paper, we define coastal lowlands as areas that are
              within coastal floodplains or would be without manmade coastal protection
              structures. Besides flooding, most of these areas are already subject to erosion
              and saltwater intrusion because of rising sea level and, mainly, as a result of
              human interference with the natural flow of rivers to the sea and sediment along
              the coast.

                   Even a large part of relative sea level rise stems from subsidence induced
              by human activities, such as withdrawals of groundwater, oil, and gas, and
              drainage of land and the resulting compaction of peat and clay underlying it.
              In some cases -- such as the Netherlands -- the fact that relative sea level rise
              and its consequences are already being faced would make communities less
              vulnerable to global warming because physical and political infrastructures to
              address the problem already exist.     In other cases, existing subsidence has
              eliminated the safety margin that might otherwise have allowed communities to
              tolerate the projected rise in sea level over the next 50-100 years.

                   This paper summarizes the implications of sea level rise for low-lying
              coastal areas around the North Sea and the Atlantic coast of Europe.



                                                     242










                                                                                       Jelgersma

          ENVIRONMENTAL CONDITIONS

                Coastal lowlands comprise the lands where sediments are deposited by tides,
          storm surges, and some areas flooded by river water -- namely, those in which
          flooding results because of the backwater effect from the sea.           The sediment
          deposited includes peats, clays, silts, and sands generally lying below the
          pre sent spri ng t i de 1 evel ; at s 1 i ghtl y h i gher al t i tudes, they al so 1 i e al ong the
          inland margins of the coastal lowlands. Although coastal lowlands are usually
          within a few meters of sea level in the case of coastal dunes they can accumulate
          to several tens of meters above sea level.

                The coastal lowland itself shows a great variety of morphology and
          lithology. Rivers entering the sea can have deltas that show great variation due
          to dominant processes of waves, currents, and fluvial input.        If river input is
          low and/or the tide ranges are relatively great, estuaries are found instead.
          Inland from the shoreline, there are generally coastal wetlands, with zonations
          primarily dependent on the vegetations' tolerance of salinity and frequent
          flooding.

                Along certain coasts, coastal barriers with dunes on top of them and barrier
          islands can occur with coastal wetlands in the hinterland. During the Holocene
          rise in sea level, these zones of different environments have shifted landward;
          if sea level rise accelerates, their landward migration will do likewise.

                There are no important deltas in northern and western Europe. Most of the
          rivers end in estuaries, like the Elbe, Weser, and Ems estuaries in Germany; the
          Rhine and the Meuse Scheldt estuary in the southwestern Netherlands; the Severn
          and Thames in England; the Somme, Seine, and Gironde estuaries in France; the
          Tajo estuary in Portugal; and the Guadalquivir estuary in Spain.

                In large measure because of the configuration of the southern North Sea
          Basin, storms from the north and west can produce extremely high tides, which
          have caused severe flooding many times throughout the last several centuries.
          This configuration also contributes to large tidal ranges: macrotidal (>4 m)
          conditions prevail along the English Channel, along the Strait of Dover, and in
          the Bristol channel. The highest tidal range of Europe can be found in the Bay
          of Mont-Saint-Michel (12 m) in France. Figure I roughly indicates the coastal
          lowlands, the river estuaries, and the delta.


          LAND USE

                For centuries,     Europeans   have drained and reclaimed wetlands for
          agriculture, industry, and housing of large cities. The draining has caused land
          subsidence through compaction of peat and clay soils; moreover, land surfaces
          have also been lowered because the compaction of unconsolidated sediments --
          which would be occurring even without human interference -- is no longer offset
          by the deposition of sediment from floods. In many areas, compaction has been
          so great that these soi 1 s are now lyi ng bel ow mean sea 1 evel . Accordi ngly, they
          have to be drained by pumping, and many areas are protected by dikes against

                                                    243









               North and West Europe

               storm surges and high tides. The only extensive natural areas left are the tidal
               flats of the Dutch, German, and Danish Wadden Sea.

                    An important side effect of this intense drainage is the intrusion of
               saltwater.   The damming of rivers diminishes the freshwater flows that would
               otherwise push saltwater back toward the sea.      Dredging in the estuaries and
               deltas in the interest of port development has also caused saltwater intrusion
               farther upstream. This shift of saline water has affected the. intake of water
               from the river for irrigation and other water supplies. Yet another side effect
               is saltwater, intrusion in coastal aquifers (see Titus in the section on Problem
               Identification).

                    The coastal lowlands of Europe, especially the river estuaries and deltas,
               are areas of dense population and heavy industrial activity. More details about
               human activities, land use, and vulnerability to flooding, especially by a rise
               in sea level, should be given on smaller scale maps by the European countries
               involved.   An example is the maps of the southern North Sea Basin.         In the
               region, about 20 million people live below the high-tide level. The economic
               value of these low-lying areas is enormous. These areas are also gateways to
               industrial areas in the hinterland as well as oil and gas fields; there is a
               heavy concentration of pipelines, refineries, and oil harbors in the southern
               North Sea.    The population density and important industries in the coastal
               lowlands surrounding the southern North Sea Basin make them very vulnerable to
               sea level rise.



               EFFECTS OF A FUTURE RISE IN SEA LEVEL

                    An accelerated rise in sea level would (1) increase the risk that reclaimed
               lowlands will be inundated; (2) accelerate coastal erosion, threatening both
               structures and recreational beaches; (3) increase the risk of flood disasters;
               (4) impair the effectiveness of drainage systems; (5) increase saltwater
               intrusion into groundwater, rivers, bays, and farmland; (6) damage port
               facilities; (7) threaten the wetland habitats of birds, fish, and wildlife; (8)
               shift sedimentation in rivers farther upstream, hampering shipping; and (9) alter
               tidal ranges, which might exacerbate many of the other effects.

                    Other impacts of global warming could also be important.     If wind patterns
               and climate change, the runoff from rivers will increase in winter and decrease
               in summer. The increased runoff can create problems for the embankments, and a
               decreased runoff can cause extensive saltwater intrusion upstream.        Increased
               storminess could be even more important:        the most significant damages on
               coastlines occur during storm surges at the time of high tide. If this increase
               in storminess should occur along the coasts of the southern bight of the North
               Sea, the highly populated, industrialized coastal lowlands would suffer
               disastrous losses.






                                                      244










                                                                                   delgersma

          RESPONSE TO SEA LEVEL RISE

               How can the coastal lowlands of Europe respond to the predicted rise in sea
          level? They can either try to defend the lowlands or move present activities and
          development landward.    The land can be protected by dikes, seawalls, beach
          nourishment, and other engineering solutions, but economic and environmental
          impacts can make such a protection strategy unacceptable.      On the other hand,
          moving present activities landward also will have serious economic and social
          effects.   Well-developed countries such as a united Europe will have the
          organization, the technology, and the resources to make these tradeoffs, unlike
          less developed countries, which lack the above-mentioned infrastructure.

               Sea level rise and the implementation of response strategies will have
          serious effects on individual, regional, and national economic levels. Impacts
          on real income include the loss of production from land and seas as well as the
          effects of employment changes from reconstruction.       Migration of people and
          enterprises will disrupt existing economic and social structures.

               Many European coastal lowlands are in critical balance with the present sea
          level and are in great danger of flooding if storm surges occur. Important parts
          of the shorelines are affected by erosion, especially during storm surges. At
          places where shorelines are eroding, stone jetties and concrete or wooden groins
          are built to lessen sand draft. This method is disputable because it seems to
          be causing more erosion on the rest of the unprotected shoreline.             Beach
          nourishment seems to be a more successful method of protection.

               But a strategy is more than a set of physical structures or laws governing
          what and where people can build. We need to systematically analyze which areas
          are vulnerable, as well as the legal, environmental, economic, and cultural
          implications of each of the possible responses. Only then will it be possible
          to rationally respond to the risks of accelerated sea level rise.



















                                                 245











                   IMPACT OF A FUTURE SEA LEVEL RISE IN THE
                              POLISH BALTIC COASTAL ZONE


                            KAROL ROTNICKI & RYSZARD K. BOROWKA
                                Department of Paleogeography
                                Quaternary Research Institute
                                  Adam Mickiewicz University
                              Fredry 10, 61-701 Poznan, Poland






         ABSTRACT

              About 3,645 square kilometers of land (1.2% of the total area) in Poland are
         less than 20 feet above mean sea level. The area at greatest risk, located below
         1 m above sea level, is 1,550 square kilometers, of which 70% lies in the delta
         of the Vistula and 12% lies in the lower Odra valley and around Szczecin Bay.
         The remaining 18% below 1 m elevation is in a 300-km section of the coast between
         Wolin Island Hel (at the end of the Hel Spit). These areas have 1.80/0 of Poland's
         population.

              In the area at risk, there are four large shipyards with capacity equal to
         2% of world production, a large chemical plant at Police, an oil refinery in
         Gdansk (processing 6 million tons/year), railway junctions, plants of the
         machine-building industry, the lower Odra power plant, and the whole of the old
         city of Gdansk, a priceless cultural center. Within the low-lying area, there
         are 28 holiday resorts and sandy beaches. Eighteen holiday resorts are situated
         above the cliffed-coast and are exposed to erosion rates of 40-150 cm/yr.

              At present, the awareness of the impacts of sea level rise is low, both in
         society in general and in the administrative units.


         INTRODUCTION

              Intensive emission of C02 induces the so-called greenhouse effect.        This
         will increase global temperature, which will bring about a faster melting of
         glaciers and inland ices, as well as thermal expansion of the ocean water.
         Forecasts indicate that during the next 100 years, these factors may cause sea
         level to rise from 50 to 200 cm. This rise will pose a number of threats to the
         natural and cultural environments of the coastal zones of maritime nations.




                                                247









               North and West Europe

               NATURAL FEATURES OF THE POLISH COASTAL ZONE

               Sea Level Changes and Storm Surges

                    Changes in coastal water levels in Poland have been recorded by 21
               marigraphic and gauging stations (Figure 1), many of which have been operating
               for the last century. A clear cycle of changes in the sea level can be observed
               in periods of 19-20, 7-11, and 3-5 years. The first two are connected with
               changes in the activity of the sun; the origin of the last cycle is obscure
               (Jednoral, 1984; Dziadziuszko and Jednoral, 1987). The regression lines and
               equations show that there has also been a gradual rise in sea level over the last
               hundred years (Figure 2). The tendency has accelerated markedly in recent years.
               The mean annual sea level rise over more than a hundred years amounts to +0.7
               mm/yr in Swinoujscie, +1.1 mm/yr in Kolobrzeg, and +1.2 mm/yr in Gdansk. For
               the last 35 years (1951-85), the rate of rise is generally higher, reaching +1.4
               mm/yr in Swinoujscie and +2.9 mm/yr in Gdansk.

                    Poland experiences severe storm surges. Surges greater than 570 cm have
               a probability of 0.75% in any given year. From 1951 to 1975, storm surges
               occurred very irregularly, from none to seven in a year (Majewski et al., 1983)
               (Figure 3). Over the last 700 years, 82 storm surges have exceeded 1.2-1.5 m.
               In 31 of these cases, sea level rose by more than 2.5 m (maximum <3.0 m),
               exceeded 600 cm, and none was higher than 650 cm (Jednoral, 1984). During the
               period of systematic observations, the highest intensity of storm surges took







                                                                        

                                            
                                                                           Puck
                                         W         Ustka                        Hal

                                            S                             Gdynia         Krynica
                                              AVe'lowo                      Gdeh9kV twibno MQ,Sko
                                                                                    a     0.,
                                                                  .......                   Tolkmicko

                                                                                           EqM49
                                                    
                                   
                                                          

                       
                        
                                                                                                                                                                                         





               
                                        ..........



                                
                                                                                              

                 
                                                   
                                                       
               Figure 1. Wind conditions, air temperature and precipitation (A), directions of
               longshore currents (B) along the Polish coast.

                                                     248
 




                                    520-     twinoujdcie                                              Rotnicki and Borowka

                                                                                                            0
                              E     Soo                                           of 0    0 %00 .00,
                                             0.0     0.0 0 0 0        0 00 0 00 40000 0we 0.        0 of 0   Ip 0 So
                                                             90 00
                                            0         0 0    90       00                  0-0   0
                                               0
                                    480-


                                       Isso          Isso             1900    192e        1940        1960          w




                                    520-
                                             Kolobrzeg
                                                                                                         0           00
                                    500-                                  0     :go 0     0 00  e0 00   0 gft,o
                                                 0                                                           0 "00 a
                                                                      0So %o                              0
                                                 0           00            0               -o       o
                                                                      0000    0%          o :0    0
                                                         o 09
                                    480-        00 o     &
                                       1860          1@80             1@00    1920        19,40       1940          19,80



                                    520-
                                             Ustka

                                                                                                            0
                                                                          0     0000      .0 so 0  0 0%       0 O'e. 0 0
                                    500-                                        0             0 0
                                                                             or        @ooo         ,6         '-oeo
                                                                               %



                                    480-
                                       18"Go         480              19,00   420         440         1100          1900



                                    520-
                                             Gdahsk                                                                  0

                                                                                                                0
                                                                                                               0
                                                                                       0         0 0 Soo
                              E     500-                      a          0.       00 %      00      0 0 0       0
                                                                      0 "   0 0                 0
                                                                      000       0         000           0     0
                                                           goo        0


                                    480-
                                       Isso          1"o              400     420         19'40       469           "so
                                                                                                -0
                                                                          0       o       0 `W@w - -
                                                     0                0  0 0- -0 00 00
                                                     0                 -     so 0      - @-..-o
                                                                % @0---











                                                                      @
                                                                      0                      o
                                                                      -o              %         .09 0 @0-0- -- - 7oo
                                                                      0     or, @



                                                                            years
            Figure 2. Sea level rise during the last century in the Polish coastal zone.
            (Czekanska, 1948). From 1951 through 1980, 88 storm surges occurred; 15 of these

                                                                       249







              North and West Europe
                                     RECURRENCE INTERVAL (YEARS)

                       CM    1.01      1.5 2        5   10   20    50   100      500
                       700-       1  1 1.I i I      i

                                PROBABILITY OF
                                A STORM SURGE
                                HEIGHT


                       650---

                                   Swinouj6cie

                                   Gdahsk
                                   Wladyslawowo -                                      10 W
                                                                                          0
                                                                                          cc
                       600--                    X..

                    W                                                                     cc
                                                                                          0

                                                                                          co
                                                                                        5 U.
                                                                                          0
                                                                  PROBABILITY OF
                       550-                                       A STORM SURGE           Uj
                                                                  NUMBER PER YEAR
                                                                                        0 Z
                             .99  .9  .7   .5   .3       .1  .05   .02 .01           .001

                                   PROBABILITY OF BEING EXCEEDED IN ONE YEAR


              Figure 3. Probability of storm-surge height and of number of storms per year
              in the Polish Baltic coastal zone. Probability curves counted on the ground of
              data published in Majewski et al. (1983).


              pl ace at the turn of the 19th century.      About 55% of storm surges develop
              withwinds from the north, 31% from the northwest, and 14% from the northeast.
              The northeast wind creates the highest and most dangerous storm surges.

                   River mouths are important sources of longshore material and are also zones
              of discontinuity in the dune belt. Therefore, they are places where storm surges
              can penetrate the coastal barriers onto usually low-lying areas behind them.
              On the Polish coast of the Baltic are the mouths of two rivers with drainage
              basins exceeding 100,000 kM2  (the Vistula and Odra Rivers) and six rivers with
              basin areas of 1,000 to 3,000 km' (Figure 3).

              Geomorphology

                   The 493-km Polish coast consists of alternating cliffed (105 km) and barrier
              beach sections (373 km). Swampy coastal sections occupy about 15 km (Figure 4).
              The cliffs are 15-40 m high, with a maximum of 90 m; 45 km of cliffs are
              retreating between 0.4 and 2.3 meters per year.      At the cliff base one can
              observe low beaches (0.4-0.8 m) with one or no submerged sandbars in the breaker
              zone (Rosa, 1984). A striking example of coastal erosion is the ruins of the
              church at Trzesacz, which was built in the 12th century about 1,800 m from the

                                                     250









                                                                   Rotnicki and Borowka








               Olt @-
           C@


                                                            so
                                                0



                                             SM2                  =3

                                                                      8
                        ;jM6                 P;@@iJ7

        Figure 4. Geomorphology of the Polish coastal zone. I    ground moraine plateau,
        2 - end  moraine hills, 3 - alluvial and glaciofluvial plains, 4 - glacio-
        lacustrine plains, 5 - swampy plains, 6 - cliffed coasts, 7 - barrier coasts,
        8 - mean annual rate of the cliff abrasion (meters per year - in numerator) and
        cliff height (in meters - in denominator).


        coast. Figure 5 shows the church and other areas threatened by erosion. Figure
        6 illustrates structural response to this erosion.

             Coastal barriers are especially well developed in the eastern and middle
        parts of the Polish coast. They separate old marginal valleys and terminal
        depressions of the last inland ice from the sea, allowing coastal lakes and
        swampy plains to form.    On the Polish coast three types of barriers can be
        distinguished:

             1. Barriers of a modest width (<0.5 km) occupied by a single row of dunes
                3-6 m high.    They are already susceptible to destruction by storm
                surges, especially because the adjacent beaches are low (0.6-0.8 m).

             2. Wide barriers (<2.0 km) occupied by several rows of dunes with heights
                up to 20 m. Beaches extend up to about 1.0-1.2 m above sea level.

             3. Wide barriers (about 2 km) occupied by complexes of parabolic and
                barkhan dunes that are 20-50 m high.    Foredunes can be found only near
                the beach, and their heights vary from 3 to 10 m. On the Leba Barrier,
                for example, there are also fields of migrating dunes with barkhans
                shifting east by about 10 meters per year.

                                              251



























                                  4L
                                                                                                      Y             12*








                                                                              A




          UI







                                                                                   Figure 5. Coastal erosion in Poland.
                                                                                   (A) Ruin of the church at Trzesacz (middle
                                                                                   coast), which was 1.8 km from the Baltic coast
                                                                                   when it was built in the 12th century.
                                                                                   Tetapads have subsequently been installed
                                                                                   to slow cliff erosion.

                                                                                   (B)  The town of Ustronie Morskie (middle
                                                                                   coast) is also threatened by cliff erosion.








                                                                                           (C) Swimmers and sunbathers at Wolin Island
                                                                                           (western coast) where the cl if f has been cut
                                                                                           i nto gl aci al and f 1 uvi al gl aci al Pl ei stocene
                                                                                           deposits.







                                                               Ilk-











           Na   (D)   Leba Barrier (middle coast)
           Ln   when erosion of foredunes has
                exposed underlying peat.










                                                                                                                       Mo
                                                                                            " A@7' -W-
                                                                                                                               P"M









              A                                                                 B







                                                                                                                           7t.,











                                                                                aim                                                   L&


                                                                                          Figure 6.   Erosion protection    in Poland.

                                                                                          (A) Sarbinowo (middle coast). Concrete block
                                                                                          and concrete band protect the    cliff against
                                                                                          erosion.
              Ji  J,11,11,@@"-@
                                                                                   ANI,
                                                                                          (B) Fishing village Kuznica on the Hel spit
                                                                                          (eastern coast. ) Boul der and cl ay ri dge and
                                                                                          p
                                                                                           Hes of concrete sleepers protect the coast
                                                                                          where foredunes have been destroyed by storm
                                                                                          surges.

                                                                                          (C)     Hel   Spit near village Kuznica.
                                                                                          Artificial beach built of sand pumped from
                                                                                          the bottom of the Puck Bay.








                                                                       Rotnicki and Borowka

              There are also well-developed spits.         Hel Spit is being intensively
         destroyed by erosion at present, especially in its western part. This process
         started with the construction of the harbor breakwaters of Wladyslawowo in 1938,
         located at the base of the spit.
              Along the Polish coast are two large estuaries: Szczecin Estuary (687 km'),
         the Vistula Estuary (838 kM2) , and some coastal lakes with a total area of about
         196 km.    Low-lying wetlands behind barriers are commonplace (Figure 4),
         particularly in the deltas of the Vistula (ca. 1,650 kM2    ) and Odra Rivers (ca.
         300 kM2 ) as well as numerous late glacial marginal valleys. A substantial part
         of these areas, especially on the Vistula Delta, are depressions with an
         elevation of -1.8 m below sea level.        Since the 15th century, people have
         controlled the hydrologic conditions of the wetlands; hence a rise in sea level
         would not necessarily inundate them, but it would require increased pumping.


         CULTURAL AND ECONOMIC FEATURES OF THE POLISH COASTAL ZONE

         Land Use of the Low-lying Areas

              The Szczecin Estuarine area and the lower Odra valley areas lie less than
         1 m above sea level .    These areas are mainly wet meadows and grazing land,
         similar to areas on Poland's middle coast.      Areas between 2 and 5 m above sea
         level are mostly arable land.     In the Vistula Delta (1,653 km'), embracing 47%
         of the low-lying areas of the Polish coastal zone, agricultural land takes up
         77%, and nonagricultural land, 23%.       Of the agricultural land, 62.5% is in
         cultivated fields and 37.5% is in meadows and pastures (Matusik and Szczesny,
         1976).

              The Vistula Delta has very good soils that have facilitated the development
         of intensive agricultural production. A substantial part of the low-lying areas
         of the Polish coastal zone (1,835 km') is in polders, of which 555 kM2        are in
         depressions (Cebulak, 1976, 1984). About 67% of the polders are in the Vistula
         Delta, 18% on the middle coast, and 15% in   the Szczecin region. The polders are
         protected by a system of dikes: 975 km of dikes in the Vistula Delta, 22 km on
         the middle coast, and about 250 km in the    Szczecin area (Cebulak, 1984).

         Population

              The Polish coastal zone comprises 28    towns, which in 1985, were inhabited
         by 4.2% of the total population of Poland (i.e., 1.6 million people); of this
         total , 83% 1 ive in six towns: Gdansk, Szczecin, Gdyni a, El bl ag, Swinoujscie, and
         Sopot (Figure 7).   In 13 of these towns, 50-100% of the land is 0-5 m above sea
         level . Only 5-40% of the remaining towns 1 ie less than 5 meters above sea I evel .
              Jointly, the low-lying areas of the Polish coast are inhabi       ,ied by about
         680,000 people -- i.e., 1.8% of Poland's population. Approximately 52% live in
         the Gdansk-Gdynia-Sopot agglomeration, 23.5% in the Szczecin region, and 13.6%
         in the Vistula Delta. The remaining 11% are dispersed along a 300-km-long coast
         between Wolin Island and the tip of Hel Spit. The density of the population of
         the coastal belt lying less than 5 m above sea level is 193 persons/km', of which
         25-26 persons/km' live in rural settlements.

                                                  255







                                    North and West Europe

                                                                                                                                                                                             48.0
                                                                                                                                                                 5,4            44@     4 W=>o
                                                                                                                                                                                               @MLADYSLAWOWO

                                                                                                                                      29,0                         LEBA
                                                                                                                                                                                   238
                                                                                                                                                                            14.5                                 23.0
                                                                                                                                            USTKA                                                   232.0   H'EL
                                                                                                                                                                                                   ,U=,q
                                                                                                                29,0                                                                                GDYNIA
                                                                                                                            DARLOWO                                            27     SOPOT
                                                                                                                                                                                      98


                                                                   4.1
                                               203.0                                              KOtOBRZEG                                                                        GDANSK
                                         10 '@<                  14.@

                                                                                                                                                                                                                       ELEIL@kG


                                         @WINO    J@CIE



                                                                                                                                                                           areas lying below
                                              POL iICE                                                               0.000       cities                                           2 m a.s.t.
                                                                                                                   100.000
                                                  7!0             16.6  148                                         10,000
                                                                                                                                                                     holiday resorts with sandy beaches:
                                                                                                       12   annual trans-shipment in ports                           4@       situated on a cl iffed coast
                                                               SZCZECIN                                     in million tons (in 1979)

                                                                                                       151
                                                                                                            annual ship production                                   A        situated on a dune coast
                                                                                                            in thousand DWT (in 1979)

                                                                                                     go 1   fishing ports and annual fish
                                                                                                            discharging in thousand tons                                                     45 km
                                                                                                            (in 1976)



                                    Figure 7.                   Cities, ports, shipyards, and holiday resorts at                                                                               the Polish Baltic
                                    coast. Black sector in the circle marks the part of the city threatened by a
                                    future sea level rise.


                                    Ports and Industry

                                               The largest Polish port is Goteborg, which lies on the Baltic. Poland has
                                    four other large ports: Szczecin and Swinoujscie on the west coast, and Gdansk
                                    and Gdynia on the east coast (Figure 7). The joint annual transshipment of the
                                    four smaller ports amounted to 60 to 70 million tons in 1979. The old harbor
                                    in Gdansk and those in Szczecin and Swinoujscie are natural, situated in the
                                    river mouths; the Gdynia harbor and the North harbor in Gdansk are artificial.
                                    In addition, three small natural harbors are situated in the river mouths on the
                                    middle coast.

                                               The coastal zone has a well-developed shipbuilding industry.                                                                                                        There are
                                    several shipyards, including                                              three large ones in the ports of Gdansk, Gdynia,
                                    and Szczecin with an annual productive capacity of about 2% of the world
                                    production. The harbors and                                               shipyards have a developed industrial hinterland,
                                    which also is the location of the electromechanical, electronic, and food
                                    industries.                     Also located in                           this area are the Lower Odra power-plant, an oil
                                    refinery in Gdansk, a large                                               chemical plant at Police with a new harbor for
                                    handling chemical cargo located on the Odra River, railway junctions, and
                                    numerous architectural monuments (e.g., the Old Town in Gdansk, a priceless
                                    monument of culture).

                                                                                                                                  256








                                                                        Rotnicki and Borowka

         Tourism

               Almost the entire coastal zone has spectacular landscapes, which are valued
         by tourists. It has two national parks, on Wolin Island and on the Leba Barrier,
         and a coastal landscape park at Hel Spit. The coastal zone boasts a combination
         of sandy beaches (3 ha/km of beach), cliffs, forested and partly active dunes,
         large coastal lakes behind narrow barriers, and architectural monuments
         (Andrzejewski, 1984).

               In 1980, 14.5 million tourists visited the Polish coastal zones, which has
         138,000 beds for tourists, mostly in small localities of up to 1,000 inhabitants.
         There are also accommodations at camping grounds, of which about 50% are up to
         500 m from the beach (Andrzejewski, 1984).

         Shore Protection

               Of the 39 holiday resorts and sandy beaches (Figure 7), 16 are on cliffed
         coasts that are eroding 0.4-2.3 m/yr. As a result, a variety of shore protection
         structures have been erected on the Polish coast. The most expensive concrete
         seawalls protect about 20 km of the shoreline. Wooden and concrete groins are
         1-ocated along 58 km of the coast, but they often do not really protect the shore
         against erosion; they merely slow erosion and in so doing, create a problem
         elsewhere.    Most of the low unconsolidated dune coast is only protected with
         the help of low fences.

               In recent years, especially after storms of the 1980s when erosion caused
         the shore of the narrow Hel Spit to shrink by 50-80 m at some places and the
         water washed over in other places, boulder-and-clay ridges are being built, and
         piles of  concrete sleepers are being dumped along a 4-km section of the shore.
         However,  these are destroyed too.    In 1989,  at two points of Hel Spit, the sand
         from the  bottom of Puck Bay was pumped onto    the seashore to create a 50-m beach
         belt 2-3  m in height.
               The entrances to all the harbors      are protected against storm waves by
         jetties, usually running parallel to each       other and confining the navigable
         channels.    There is sand accumulation on      the updrift (western) side of the
         jetties, and erosion and landward shoreline movement on the downdrift side.


         IMPACT OF A FUTURE SEA LEVEL RISE

               Accelerated rise in sea level will pose direct and indirect threats to the
         low-lying areas. Direct inundation will confront the lowest areas, which will
         be below the new sea level.      Indirect threats such as flooding will face the
         adjoining, slightly higher, areas.       The natural, economic, demographic, and
         cultural resources of Poland's coastal will be seriously jeopardized.

         Impacts of a 0.5-m Sea Level Rise

               The areas lying less than 0.5 m above sea level will be inundated by a
         number of processes:      (1) the narrow, sandy coastal barriers separating the
         low-lying areas from the sea could erode, exposing inland areas to the sea; (2)

                                                  257







               North and West Europe

               river valleys will drown; and (3) groundwater tables will rise. Several other
               effects will be evident with a 0.5-m rise in sea level. Other impacts include
               cliff erosion and higher lake levels.

               Increased Cliff Erosion and Landward Movement of the Beach

                    With a 0.5-m rise in sea level, the probability of particular levels of the
               sea being exceeded during storm surges will increase markedly. Flood levels that
               today occur only once in a hundred years will recur every 3.5 to 5 years. Based
               on the cliffs that are currently exposed to similar levels of wave attack, we
               estimate that most cliffs will erode 2.3 m/yr.

               Accelerated Sediment Transport by the Longshore Current

                   The higher levels attained by storm surges will destroy foredunes and erode
               barrier islands and spits.   The lowered barriers will then be susceptible to
               storm washover, which will lead to inlet     breaches and sedimentation on the
               backside of barriers. The sedimentation will encroach either upon coastal lakes
               or upon the meadows and pastures of peat plains. As a result, the coast will
               recede and the barriers will shift landward. Especially threatened are the
               narrow barriers of the middle coast separating Lakes Jamno, Bukowo, and Kopan
               from the sea and Hel Spit.

               Higher Coastal Lake Levels

                   Coastal lakes are connected with the sea through canals or rivers.         The
               coastal barriers along the Polish coast have enclosed depressions and valleys
               of the late glacial age, forming coastal lakes and peaty marsh plains.
               Theoretically, a sea level rise of 0.5 m should increase the area of these lakes
               by 10-30%.  This, however, depends on (1) how fast sea level rises, and (2)
               whether other geological and biological processes adjust to the rate of the rise.

                   Over the last few decades, no increase in the area of these lakes has been
               observed, despite the accelerated rate of sea level rise.      On the contrary,
               because of their intensive eutrophication, the lakes tend to be overgrown, and
               their area is dwindling.   The rise in water level would have to be very rapid
               to change this tendency. Hence, a rise in the level of the lakes will probably
               enlarge the area of swamps and young peat bogs surrounding the lakes and situated
               on valley floors and low-lying plains. The sediment transported by.rivers into
               the lakes, the shift of coastal barriers southward through overwash and inlet-fan
               sedimentation, the rapid growth of vegetation on the lake sides, and biogenic
               sedimentation controlled by eutrophication are all likely to transform the
               coastal lakes to land, thus gradually destroying a zone of great landscape value.
               However, theoretically the whole of the lacustrine-barrier zone could shift
               south.

               Expanded Depression Areas and Higher Groundwater Levels

                   A sea level rise of 0.5 m will enlarge the area of depressions from 555
               km' to 1,720 km', with 63% of the increased area in the Vistula Delta, 23% in the
               Szczecin Haff region, 13% on the middle coast, and 1% in the Gdansk-Gdynia-Sopot
               agglomeration (mostly in Gdansk). These areas will probably be inundated by the

                                                     258









                                                                        Rotnicki and Borowka

         groundwater level rise; however, this too depends on the adjustment of natural
         processes to (1) the rate of sea level rise and its ingression through the
         valleys, and (2) the rate of groundwater level rise.        Most probably this sea
         level rise will make these areas swampy and will cause the development of peat
         bogs and the accumulation of phytogenic layers. Thus swamps and wet grassland
         will greatly increase in area.      The rise in sea level may even affect areas
         situated 1-2 m above sea level today.       The range of this process will depend
         primarily on (1) the intensity of the inflow of groundwaters from morainic
         plateaus onto the low-lying areas, and (2) the initial depth of the groundwater
         level.

               In polders, primarily in the Vistula Delta       (1,135 km), (1) groundwater
         will rise more rapidly; (2) the probability of particular areas being flooded
         will increase, as will the breaching of dikes due to increased infiltration of
         water during high stages; and (3) the dikes already built will be too low for
         the new hydrological conditions. The probability that the dikes already built
         in the Vistula Delta will be unable to protect polders against water is today
         less than 0.1% (i.e., a recurrence interval of 1,000 years). However, dikes can
         be disrupted because of their excessive permeability or by an ice jam at the
         mouth of a river.

               The height of the dikes is 2.2-2.3 m because Polish regulations require
         them to be 70 cm higher than the 50-year storm (i.e., annual probability of
         0.02), although sea level has risen 10 cm since some of them were built
         (Krzesniak, 1976).    If the sea rises another 50 cm, then the water level during'
         the 50-year storm will only be 10-20 cm below the dikes, 50-60 cm too low for
         comfort.

               Thus, it will probably be necessary to (1) upgrade the capacities of
         intermediate pumping stations; (2) rebuild and increase the height of dikes; and
         possibly (3) raise polder bottoms.      These problems would face polders with a
         combined area of 1,500 square kilometers, their surrounding dikes (some 1,300
         km long), and 120-200 intermediate pumping stations.        It is possible that new
         polders will have to be built on waterlogged land that will keep expanding in
         area. Given the possibility of a one- meter rise in sea level, the new dikes
         should be 3.2-3.3 m above sea level.

         Inundation of the Lower Reaches of River Valleys

               Several changes will take place in the lower reaches of river valleys,
         depending on the ability of a particular river to adjust to the rate of the
         anticipated sea level rise.

               In the Odra valley, a sea level rise of 0.5 m would increase the frequency
         of flooding over an area 3-4 km wide that extends 50 km upstream, due to both
         higher storms surge levels and the backwater effect on river surges. Near the
         coast, flood levels will generally rise 50 cm; upstream, the rise in flood levels
         will be somewhat less but still significant.         In some cases, the increased
         flooding may be mitigated if global warming reduces ice jams, which currently
         are responsible for some floods. Sedimentation from floods will tend to shift
         upstream, perhaps increasing the ability of a few undeveloped areas to keep pace
         with the rising sea -- at the expense of increased inundation downstream.

                                                  259







              North and West Europe

                   These effects will necessitate rebuilding the facilities currently
              protecting the polders, such as dikes and possibly also intermediate pumping
              stations.   In the lower Odra valley, harbor facilities and low-lying industrial
              plants in Szczecin and in Police will be threatened. Similar threats will emerge
              in the lower Vistula valley and the valleys of the lesser rivers (the Rega,
              Wieprza, Parseta, and Slupia), at the mouths of which are located harbors,
              industrial buildings, and parts of residential buildings.

              Increased Estuarine Salinity

                   The lakes will grow more saline as a result of more frequent inflows of
              Baltic waters into them through river mouths and overwash breaches of barriers.
              Moreover, a rise in sea level will facilitate contact between the Baltic and
              Atlantic through the Danish Straits. We may anticipate more frequent and massive
              storm inflows of the more saline and oxygenated Atlantic waters into the Baltic,
              which will benefit the biological life of this sea.

              Increased Groundwater Salinity

                   Higher sea level will hinder the seaward flow of groundwater and allow the
              water table to rise in the coastal zone.     Higher groundwater levels will also
              increase seawater infiltration.       This will be - reinforced further by an
              accelerated water circulation in polders and an excessive exploitation of fresh
              waters on barriers, where the drawing of freshwater from near-surface lenses
              may cause a rise in the saline water table.

              Summary of the Impacts of a 0.5-m Rise

                   Because of physiographic conditions, the zones of the contemporary landscape
              and land use probably could not shift inland.       It is imperative to keep the
              present agricultural, use of the Vistula Delta and the lower Odra Valley,
              especially in the polder areas.     Giving it up would mean tremendous economic
              losses.

                   All the ports and shipyards as well as a part of the industry and railway
              junctions located in the low-lying areas will suffer damage with a future rise
              in sea level. The extent of the danger will vary from port to port, depending
              on the following factors:

                   1.  The degree of exposure of the ports and their facilities and
                       infrastructure to waves and storm surges.     Thus, the North Harbor in
                       Gdansk and the fishing harbor in Wladyslawowo, both projecting into the
                       sea, will be most threatened by exposure, whereas the harbor in
                       Swinoujscie, situated on the west coast, will be more threatened by
                       higher storm surges in this part of the Baltic.

                   2.  The altitude above sea level of wharves, jetties, breakwaters, and other
                       facilities.

                   3.  The probability of simultaneous impacts of the rising sea level and
                       floods caused by ice jams at the mouths of the rivers on which some


                                                     260








                                                                     Rotnicki and Borowka

                 harbors are located -- e.g., in Szczecin, Police, Darlowo, Kolobrzeg,
                 and Ustka.

             4.  An increase in sediment transport by longshore currents. This, in turn,
                 will cause a more intensive alluviation of the entrances to the harbors
                 in Swinoujscie, Ustka, Darlowo, Kolobrzeg and Wladyslawowo, as well as
                 of the fairways leading to the harbors -- e.g., the 30-km long fairway
                 in the Pomeranian Gulf leading to the harbors in Swinoujscie and
                 Szczecin.

             5.  The kind, height, strength, and technical condition of the storm
                 protection structures in the harbors.     They are built to accommodate
                 the probability of storm surges of various heights. However, the rise
                 in sea level will increase the probability of storm surges that will be
                 higher than those currently planned for. As a result, various technical
                 equipment in the harbors and their storm protection structures may prove
                 to be too low and too weak. They may stop fulfilling their function and
                 may suffer more rapid destruction. A general answer to the question of
                 whether harbor facilities and storm protection structures would suffer
                 destruction in case of a sea level rise is impossible at this stage of
                 the analysis of the problem.   It requires detailed analyses for each of
                 the harbors.

        Impacts of a I- to 2-Meter Rise in Sea Level

             Such a rise would inundate another 1,200 kM2     of land (Figure 8); a much
        larger area would experience increased flooding.     The processes and phenomena
        triggered by the rise of 0.5 m will continue and intensify, but their spatial
        range will expand, and the threat they will pose to urban, industrial, and
        agricultural areas with a high capital investment level will be greater. The
        A                 B








           1 2..           a i-a 8







        Figure 8.    Location of low-lying areas along the Polish Baltic coast.

                                               261







               North and West Europe

               steep slopes along the morainic plateaus would prevent the beach -barri er- lake
               zones from shifting inland by more than 1 to 4 km.

                     Lakes will change shape, unless peat formation              and sedimentation
               accelerate.    Some lakes will unite; and cultivated fields, with the exception
               of polders, will practically disappear from the low-lying areas of the coastal
               zone.   There will be an increase in the area of peat bogs and water-logged
               meadows.    In the Odra valley, the narrow strip of the floodplain in danger
               stretches 80 km south of Szczecin; in the Vistula delta, the endangered area
               includes 1,560 km, or 94% of the delta area less than 5 m above sea level.

                     Rural settlement will have to be moved to altitudes higher than the 2-m
               contour lines. Agricultural use of this land will be possible only through         the
               building of polders in an ever-increasing area. A part of the settlements          and
               tourist accommodations on the low sandy coast will be destroyed or will have to
               move onto newly developed accretionary lands on the inner parts of barriers.
               Threatened with direct inundation will be parts of towns located less than 2 m
               above sea level and inhabited today by about 360,000 people -- mainly parts of
               Gdansk, Szczecin, Swinoujscie, and Elblag. Higher situated areas of towns will
               be threatened indirectly by flooding.-


               CONCLUSIONS

                     It is difficult to make a complete list of threats to urbanized, harbor,
               industrial, and historical areas. We can only draw attention to the main sources
               of danger. The danger starts today and will grow with the rise of sea level.
               Its main sources are (1) the insufficient height and strength of harbor
               protection facilities; (2) the increased filling up of the entrances to harbors
               and navigable channel ways; (3) the destructive action of storm surges of a
               higher frequency of given stages and ever higher; (4) a rise in groundwater
               level posing a threat to (a) the strength of foundations and grounds under
               houses, industrial buildings, railway junctions, and communication routes, and
               (b) the functioning of the urban underground infrastructure with such
               installations as stormwater drains, telecommunications, and power cables; (5)
               the appearance of groundwater on the surface of low-lying parts of towns; and
               (6) the insufficient height of artificial dikes and the possibility of a flood.

                    The Central Marine Office is responsible for planning and implementing the
               protection of Poland's seashores. The existing plans consider current erosion
               rates but would not accommodate an accelerated rise in sea level.         Also, they
               concern only the shoreline, not the entire coastal zone.           Awareness of the
               dangers from future rise in sea level is low, both among the public and within
               the administrative units. It is highly probable, however, that with the changes
               taking place in Poland today, the message of this report will get through to the
               new decisionmakers and managers in the state administration.

                    The processes already started by the rising sea will require town planners,
               designers, planning offices, economists, engineers, and decisionmakers to adopt
               a totally different approach and philosophy that will accommodate the analysis
               of the costs, risks, and effects of sea level rise. They must learn to view the
               coastal zone as a dynamic system that undergoes continual adjustment.

                                                        262








                                                                            Rotnicki and Borowka


           BIBLIOGRAPHY

           Andrzejewski , E.     1984.   Turystyka (Sum.:Tourism). In:        Pobrzexe Bal tyku.
           Augustowski, B., ed. Wroclaw: Ossolineum.

           Cebulak,   K.   1976.    System wodno-melioracyjny (Sum.:The water and drainage
           system). In: Xulawy Wislane. Augustowski, B., ed. Wroclaw: Ossolineum.

           Cebulak,  K. 1984. Gospodarka polderowa (Sum.: Polder economy).           In: Pobrzexe
           Baltyku. Augustowski, B., ed. Wroclaw: Ossolineum.

           Cieslak,   K., and W. Subotowicz, eds.       1986.    Stan wiedzy o hydrodynamice i
           litdynamice oraz ochronie brzegu morskiego.

           Czekanska, M. 1948. Fale burzowe na poludniowym wybrzexu Baltyku (Sum.: Flood
           raised by storm on the southern shores of the Baltic Sea), Badania Fizjograficzne
           nad Polska Zachodnia 11:58-96.

           Dziadziuszko, Z., and T. Jednoral.        1987.   Wahania poziomow morza na polskim
           wybrzexu Baltyku (Sum.: Variation of sea level at the Polish Baltic coast),
           Studia i Materialy Oceanologiczne 52:215-238.

           Jednoral, T.    1984.   Spietrzenia sztormowe wzdlux polskiego wybrzexa. Slupsk:
           Instytut Morski, Archives Reports., Jednoral, T.          1985.   Fale wiatrowe Morza
           Baltyckiego w swietle badan empirycznych. Slupsk: Instytut Morski, Archives
           Reports.

           Kwiecien, K.     1987.   Warunki    klimatyczne    (Sum.:Climatic conditions).        In:
           Baltyk Poludniowy. Augustowski, B., ed. Wroclaw: Ossolineum.

           Majewski, A. 1987. Charakterystyka. wod (Sum.: Characteristic of the Southern
           Baltic waters).      In:    Baltyk Poludniowy.      Augustowski, B., ed.        Wroclaw:
           Ossolineum.

           Majewski, A., Z. Dziadziuszko, and A.         Wisniewski 1983.     Monografia Powodzi
           Sztormowych 1951-1975, Warszawa: Wydawnictwa Komunikacji i Lacznosci.

           Matusik, M. 1984. Gospodarka rolna (Sum.: Agricultural economy). In: Pobrzexe
           Baltyku. Augustowski, B., ed. Wroclaw: Ossolineum.

           Rosa, B. 1984. Rozwoj brzegu i jego odci nki akumul acyjne (Sum.: The development
           of the shore and its accumulation sections).                In:     Pobrzexe Baltyku.
           Augustowski, B., ed. Wroclaw: Ossolineum.

           Slupsk: Instytut Morski, Archives Reports., Costa, J.R.,        and V.R. Baker. 1981.
           Surficial Geology Building With the Earth. Chichester:         John Wiley and Sons.

           Subotowicz, W. 1982. Litodynamika brzegow klifowych.           Gdansk: Ossolineum.





                                                      263







              North and West Europe

                               APPENDIX: CLINATE AND HYDRODYNANICS OF POLAND


              Climate

                   The climate of the Polish coast is characterized by highly variable weather
              conditions because the southern Baltic is on the path of very active cyclones.
              Moreover, it is an area of a frequent exchange of air masses advancing almost
              freely from different directions. The prevailing masses are polar-maritime air
              from the west (60.4%). Much less frequently the area comes under the influence
              of polar-continental air masses from eastern Europe (15.5%) and arctic air from
              the Norwegian Sea (9%).     The least frequent are tropical air masses (1.5%)
              (Kwiecien, 1987). The mean annual temperature of the Polish coast varies between
              7.10C at Cape Rozewie and 8.0*C in Swinoujscie. The coldest months are January
              and February, with mean temperatures from -0.60C in the west to -2.40C in the
              east (see Figure 1). The warmest months are July and August (16.1-17.20C). The
              mean precipitation depends on the degree of exposure of the coastline to
              rain-bringing westerly winds. Thus, the highest mean annual rainfall is recorded
              on the middle coast between Darlowo and Leba (650-700 mm), while the remaining
              areas receive much less rainfall (550-570 mm).    The highest mean monthly wind
              velocities (5-7 m/sec) are characteristic of the autumn-winter months, whereas
              the lowest are recorded from May to August (2.5-3.5 m/sec). The autumn-winter
              season contains the greatest number of days with strong winds (29 days: 6-70C)
              and storm winds (18 days: >80C).

              Hydrodynamics

                   The direction of the longshore current is controlled by prevailing winds,
              and sediment in the littoral zone is generally transported from the west to the
              east (see Figure 1). It is only between Kolobrzeg and Swinoujscie that westward
              sediment transport can sometimes prevail. During storms, rip currents 50-200
              m apart appear that are almost perpendicular to the coastline. In the deep-water
              zone, about 85% of waves are not higher than 3 m or longer than 7 sec. As much
              as 95% of the waves are not higher than 4 m or longer than 8 sec.         In the
              offshore zone, storm waves attain a height of I m above the current mean sea
              level, and reach 2 m only in the zone of a steeply sloping coast (Jednoral,
              1984).















                                                     264











                       ADAPTIVE OPTIONS AND IMPLICATIONS OF
                       SEA LEVEL RISE IN ENGLAND AND WALES



                        IAN R. WHITTLE, CHIEF ENGINEER, MICE FIWEM
                                     Flood Defense Manager
                                   National Rivers Authority
                                         London, England






          ABSTRACT

               On July 10, 1989, the National Rivers Authority was established as the major
          flood defense agency for England and Wales, with the regionally based staff
          transferred from the regional Water Authorities.        One of the Authority's
          principal roles is to coordinate and plan flood defense strategies and to
          undertake appropriate defense programs.

               As an island nation, the United Kingdom has a significantly high percentage
          of low-lying land already at risk; rising sea levels will increase that risk.
          Coastal land use is a mix of rural, urban, residential, commercial, and
          industrial zones. This paper identifies the location of flood-prone areas and
          refers to some of the socioeconomic aspects of those unprotected areas.
          Reference will be made to the storm of 1953 and the defense systems constructed
          subsequently around the coast and along the river networks.

               The principles used to develop the design defense level for the Thames
          Barrier is also summarized.   We review the present policies for flood defense
          and the short-term interim approach needed to respond to any additional threat
          from sea level rise.

               Long-term strategies cannot be developed until predictions from global
          circulation models become more reliable. This paper refers to current research
          programs to analyze the effectiveness of the present generation of defense
          structures and identifies some of the constructional adaptations that would
          increase their effectiveness.

               Some reference is made to the implications for agricultural lands if the
          rainfall patterns deviate from those of the present day. Rising sea levels may
          preclude the use of gravity outfalls and low-head pumping stations.

               The United Kingdom has an extensive data-gathering network to aid the
          monitoring of rainfall, river flows, and'river levels in real time. Tidal and

                                                 265









               North and West Europe

               storm-surge forecasts can be undertaken with a considerable degree of accuracy.
               The tidal gauge network can be monitored, again, in real time, to check these
               predictions.   This paper shows that the United Kingdom's ability to issue
               reliable flood warnings to inhabitants in urban and coastal areas is well
               advanced.

                    Finally, this paper comments on the use of benefit/cost analyses to support
               policies, as well as the effects of the new European Community Directives for
               environmental and wildlife protection as a component of the flood defense
               policies.


               INTRODUCTION

               Legislation

                    The government departments responsible for flood defense policy are, in
               England, the Ministry of Agriculture, Fisheries, and Food, and, in Wales, the
               Welsh Office.   The 1989 Water Act established the National Rivers Authority.
               This act transferred to the new Authority from the former regional water
               authorities responsibility for supervising all matters relating to flood defense,
               and for undertaking functions set out in the 1976 Land Drainage Act. Among other
               things, the new act gave the National Rivers Authority responsibility for
               safeguarding the water environment; for improving water quality and resources;
               for enhancing the environment, amenities, and recreation facilities; and for
               developing, in conjunction with the Ministry of Agriculture, Fisheries, and Food,
               strategies for flood defense and flood warning systems. The act also provided
               for the establishment of utility companies to deal with water supply, sewer
               systems, and sewage treatment.    (Scotland and Northern Ireland have separate
               legislation, so policies and practices in these two countries are excluded from
               this paper.)

                   The powers to deal with problems of erosion of coastal land not subject to
               flooding are exercised by 88 Maritime Councils in England and Wales under the
               Coast Protection Act of 1949. As in the case of flood defense, the government
               departments that have overall responsibility are the Ministry of Agriculture,
               Fisheries, and Food in England and the Welsh Office in Wales.       The National
               Rivers Authority has no responsibility for this area of activity; thus, no
               further reference will be made in this paper.

                   The National Rivers Authorities exercises its functions through nine regions
               in England and one region in Wales (Figure 1).    Before the new act's passage,
               ten regional water authorities managed all aspects of the water cycle.

                   As the principal flood defense agency in England and Wales, the National
               Rivers Authority not only has powers to construct all types of flood defense
               works and land drainage works, both on statutory main rivers and on the coast,




                                                     266










                                                                                Whittle


                              National Rivers Authority
                                   Regional Boundaries





                                              North-
                                             umbria

                                     North
                                      West


                                                   Yorkshire









                                          Severn Trent
                                                                Anglian
                             Welsh




                                                      Thames



                                         Wessex
                                                             Southern
                         South West







         Figure 1. The ten regions of the National Rivers Authority.

                                               267









              North and West Europe

              but also has general oversight of 250 Internal Drainage Boards and the county,
              district, and metropolitan borough councils.

                   Within the ten regidns, flood defense functions are carried out by Regional
              Flood Defense Committees, each under a chairman appointed by the Minister of
              Agriculture, Fisheries, and Food. Four of the regional committees have developed
              their functions to local flood defense committees. The boundaries of the areas
              of regional and local committees are "river catchment based" and have evolved
              over a 50-year period as* a consequence of the various land drainage acts
              preceding today's statutes.     These four regions share a total of 18 local
              districts.

              Funding of Flood Defense Works

                   Any of the above flood defense agencies undertaking improvement works that
              can be regarded as a capital investment may be eligible for funding from the
              national government. The level of the grant may range from 15 to 55%, with the
              actual rate depending on the type of flood defense agency and, in the case of
              the National Rivers Authority, the scale of local district programs and the
              ability of the local population to pay for them.      Sea defense works or river
              works to protect against tidal flooding attract a 20% supplement added to the
              above rates.

                   The balance of the cost of the capital works, together with the costs of
              all maintenance works, staff costs, all overhead costs, equipment costs, etc.,
              are met out of revenue raised individually within the local districts.

                   The National Rivers Authority is currently spending some E67m (over 100
              million U.S. dollars) per annum on capital works. The majority of this amount
              goes toward building or reconstructing flood defenses. This level of investment
              is expected to increases, in real terms, over the next decade by as much as 50%.
              Through grants, the Ministry of Agriculture, Fisheries, and Food provides
              approximately 30% of the cost of the capital works program; this contribution
              also will increase. Finally, almost as much is being spent on the maintenance
              of existing structures, defenses, and water courses.


              SEA LEVEL RISE - PROTECTIVE MEASURES


              Historical

                   Until some 8,000-10,000 years ago, much of Great Britain was covered with
              a deep ice sheet. The northern part of England and Wales was covered by thick
              ice, while land to the south of this sheet suffered varying intensities of ground
              freezing.  At this time, the sea level would have been up to 100 meters (330
              feet) lower than today, and the present sea bed of the English Channel and
              southern North Sea was exposed as dry land. Thus, Great Britain was apparently
              part of the European continent (Brunsden, et al., 1989).



                                                     268








                                                                                        Whittle

                As a consequence of a gradual rise in global temperature, this ice sheet
           melted and sea level rose. Over time, the ancient deep river valleys and lakes
           gradually silted up and the layers of the superficial deposits became
           interspersed with layers of vegetation, resulting in a complex, stratified
           arrangement of organic and inorganic materials.

                Despite the silting processes, much of this land still lies below present-
           day sea 1 evel . Some of it i s as 1 ow as 7 meters bel ow the sea, but the majority
           lies between 0 and +5 meters (Figure 2).       These areas have a high level of
           natural fertility, and, over many centuries, inhabitants have raised embankments
           to exclude either seawater or riverwater.     These embankments were constructed
           at what was the edge of the sea.       Gradually, the lower lying land that was
           seaward of the defenses was covered and raised by further deposits of marine
           sediments. As the resulting salt marsh grew, new defenses were constructed at
           the new seaward limit. Each of these successive embankments was constructed to
           a much larger cross-section and to a higher level than the earlier ones.

                These progressively larger defenses were needed because the sea and river
           levels were rising relative to the land and because higher standards of defense
           were required to protect the increasingly larger areas of land carrying the ever-
           increasing valuable agricultural and horticultural industries.

                England and Wales cover an area of approximately 15 million hectares.
           Agricultural land is graded using a five-category land classification system.
           The Ministry of Agriculture, Fisheries, and Food has conducted some work on
           identifying areas at risk, and a paper on this subject was presented at the 1989
           Loughborough Conference (Whittle, 1989).      About three-quarters of a million
           hectares of land lie below +5 meters Ordnance Datum Newlyn (ODN). (Note: ODN,
           similar to NGVD in the United States, refers to a fixed elevation that was at
           sea level when the datum was established.) Within this lie some 640,000 ha of
           land, (8%), Grades 1-3, of which nearly 200,000 hectares are classed as Grade
           1 land.

                In the early days, these lowlands were frequently inundated and,
           consequently, not conducive to occupancy by settlers.       So for the most part,
           settlements developed along river estuaries, especially where a high-level spit
           or area of land was free from frequent inundation. Today, many of these early
           settlements alongside rivers have become established as major commercial and
           industrial zones supported by the necessary infrastructure and residential areas.
           Progressively, demand for developable land has meant extension into zones where
           risk of flooding is high. Thus, higher standards of defense have been demanded.
           In common with many developed countries, the United Kingdom now has billions of
           pounds of real estate investments in rural and urban zones--to say nothing of
           the hundreds of thousands of people, protected from sea and tidal flooding, all
           of which will require continued protection against a rising sea level.

           Post-1953 Tidal Surge

                A major tidal surge struck along the east coast of England in 1953. Some
           300 people died, thousands of hectares of land were inundated with saltwater,



                                                   269






                         North and West Europe
                                                        ride Game                                                           F1        Land below 5 metres AOD
                                                                41W               "Will
                                                                      1.7         nktra III                                           Land between 5 & 10
                                                            3.2              1" W doom
                                                                                                                            M         metres AOD
                                             loWdomwo         -      10.2  SMW ww d
                                             MW Will
                                             MM

                                      The boxed infonnation on thi's map - supplied by the
                                  Proudman Ocew"mphic Laboratory - s@owvrece. t trends                                       th Shield
                                     in as W491 computed from records at eighttide quages                                 3757
                                          in the national network maintained bV MAFA


                                                                                              Y.,








                                                                                                                                      M
                                                                                                                                    MR.


                                                                                                                                                         Imm' h
                                                                                                                                                              Ina am
                                                                                                                                                                .!.o
                                                                                                                                                         3-
















                                                                               M. M,
                                                                                                                                   @4,
                                                                                                       -wo
                                                                                                  M



                                                                                                                                                                                Sh     on
                                    KAM@fcrdHs"nl                                                                                                                            LL
                                                                                                                                                                                .69j 1204
                                      4.491112.4
                                                                                                                                                                                2.8
                                    [@3.3





                                                                                                                                      Part       h




                                                           I Devonport I
                                                           LLO-9i !.0.68 1
                                                              2. 1 ft I
                                                                     n
                                                                8 +
                                                               6













































































                                             +1.7

                                      2_


                        Figure         2. Low-lying land in England and Wales.

                                                                                                       270











                                                                                         Whitt I e

            and vast urban areas were demolished or seriously damaged. Many kilometers of
            sea defense were breached, demolished, washed away, or overtopped.         The surge
            caused a tide-lock condition in many rivers, causing them to overflow their banks
            and flood low-lying lands.

                 Since that storm, at that time the worst recorded in living memory, the
            catchment boards and their successors (river boards, followed by river
            authorities, water authorities, and the National Rivers Authority) have
            reconstructed, raised, or constructed most of the 1,000 km of sea defenses and
            the many thousands of kilometers of tidal defenses.         However, many of those
            defenses have reached the end of their useful lives.        Earthen embankments may
            have a life of only 25 years and are being reconstructed, and some hard sea
            defenses, which appear to have led to increased beach erosion, need either
            complete reconstruction or, at least, a new and deeper foundation at the front
            toe.

                 The surge of 1953 threatened the center of London (Figure 3). The decision
            was taken then to implement a long-standing proposal to protect London:            the
            Thames Barrier.

            The Thames Barrier

                 The Thames Barrier is unique in concept.     It consists of a series of gates
            that are rotated upwards out of cills set into the river bed (Figure 4). The
            Barrier has been designed to afford a standard of protection against a one-in-
            one-thousand year storm surge, including sea level rise expected through the year
            2030.

                 The level of the top of the gate was determined as follows:

                 1.  Tide levels at Southend, the mouth of the estuary, were analyzed to
                     determine the one-in-one-thousand year return period.

                 2.  The hydrodynamics of the river were analyzed to translate the Southend
                     data of tide levels to the Barrier site.

                 3.  The trend line of the rise in river levels at a location near the
                     Barrier site was analyzed to establish the relative rise in water level,
                     and then extrapolated to the year 2030 (i.e., 50 years following the
                     completion date of the structure).

                 4.  The Barrier structure and gates are designed to resist a static force
                     from some 9 meters (29 feet) of water.

                 The Barrier has been designed to permit water to spill over the top of the
            gates.   Upstream of the Barrier, the river extends for a tidal length of 40
            kilometers (28 miles).     If the Barrier is operated sufficiently early in the
            tidal cycle, a "reservoir" of this length, and 9 meters deep, has little chance
            of being filled on any one extreme event.         Furthermore, the gates could be
            rotated further to gain another 2 meters (6.5 feet) in height, provided that

                                                     271







              North and West Europe







                            't' 0
                                                        JR


                                               7

                                  OWN















                                               .............







                                                        Ut








                                                                               ... ..........
              Figure 3. What London would have    looked like if the flood had been just a bit
              higher.


              minor alterations are made to the cills (Figure 4). Thus, the Barrier is capable
              of modification to effectively protect London well into the next century against
              the worst case predictions of sea level rise (at least given current storm
              severities) (Kelly, 1989).     In 1982, the Barrier and associated riverside
              defenses from Southend, at the river mouth, to Teddington, at the tidal limit,
              were tested when the Barrier, although not quite complete, was closed against
              a high-surge tide. The Barrier has been operated against adverse conditions on
              four occasions.

              Other Structures Along the Thames

                   Besides the Thames Barrier itself, other rivers and creeks have been given
              protection by new barrier structures. Most of these consist of drop-leaf gates
              set between towers.   Those and other gated structures along the Thames would
              probably need structural reanalysis to determine their suitability for
              modification.


                                                     272







                                                    Whittle
                                             Design flood level


                               @WST
                                             1953 flood level

                               LWST
                               - --  -= =-=i == Z@@ @5-6 Pk.
                              Riv r bed
                           0               0

                      open position  Flo od control position






                                               HWST








                     0

                     Undershot ow position Maintenance position
                           HWST-high water, spring tides
                           LWST-low water. spring tides

                  Barrier gate in four positions





                         7-77;,





                                             13


                                     N
      'OW






      Z







                 t

                         'P.





                                                           7,
                                                        4,

                                               N@-
                                              31-




      Figure 4. (A) The Thames Barrier concept and (B) barrier in pl ace on Thames
                                             195311,
                  -ZOO              0

                                               H,















































      River.


                              273








              North and West Europe

                    Barriers apart, many of the remaining defenses along the Thames consist of
              conventional hard defenses of varying design. Some may have adequate foundations
              and stability to receive an additional crest to gain extra height.             Other
              defenses, such as soft earthen embankments with protected front face, may also
              be capable of being raised merely by the addition of extra material. Elsewhere,
              however, where the foundations and subfoundations consist of soft alluvial soils,
              it is unlikely that additional weight can be added to these structures.           An
              extensive program of geotechnical investigation will be required to find the
              optimal solution.

              Other Defenses in England

                   The areas of land in England and Wales at risk are protected by a variety
              of defenses.    In the main, these defenses have been constructed from soft
              materials excavated from adjacent lands, but some occur naturally, such as sand
              dunes.   Soft, artificial defenses have a short life,     and many of those built
              since 1953 are now showing signs of stress and are being rebuilt, often by
              substituting a concrete or stone structure to meet the higher standards needed
              for the future.

                   Some navigable rivers within the United Kingdom      have been supplied with
              barrier structures, particularly the river at Hull and    the Fosse River at York.
              These structures have been designed with significant      "air draught" to permit
              navigation.

              Lowering Beach Levels

                   The United Kingdom, in common with other parts of the world, is experiencing
              a general lowering of beach levels and, frequently, loss of the protective
              foreshore and salt marsh in front of the soft defenses.         The cause of this
              decline is alleged to be inability of the surf zone to move shoreward because
              of the presence of some obstructing defense. Accordingly, it has been shown that
              foreshores are becoming steeper (Halcrow, 1989), which will aggravate problems
              associated with defense management policies.

                   It can be shown through experimental work that the rate at which the beach
              level is being reduced is affected by the type of obstructing defense.             A
              vertical profile wall creates reflective waves, which aggravate beach scour,
              although these damaging effects may be reduced by a "stepped" profile.           An
              alternative profile to combat the adverse effect of walls is to use an embankment
              that permits waves to "run up" the face of the structure and thus dissipate wave
              energy.


              OPTIONS FOR COMBATING SEA LEVEL RISE

              Allowances in Design of Sea Defenses

                   It has been recognized for many decades that as a result of the retreat of
              the ice sheet, northern England is rising and southeastern England is sinking.

                                                     274











                                                                                             Whitt 7e

           This isostatic change has contributed to a relative rise in sea level in southern
           Engl and.   An overall allowance on the order of 3 millimeters per year has,
           therefore, been included in the recent designs for sea defenses.

                 Most of the defenses along the east coast of England are open to a long
           fetch to the Continent and can experience severe wave action. An allowance of
           up to 2 meters may be provided.        Soft defenses built from marine alluvium and
           clay soils suffer from shrinkage in the upper drying zone. An allowance of up
           to 1 meter for this effect is added to the design still-water level. Obviously,
           concrete walls do not have this component of safety, so crest levels of such
           defenses are lower. These allowances, together with any additional allowances
           that appear pertinent, are added to the basic still-water level (tide plus
           surge).    The base still-water level is that for 1953 or any later event that
           resulted in a higher level.

                 It is appropriate to consider the allowances that should be included in
           the design of new flood defense works for sea level rise.              There i s so much
           uncertainty about future storm patterns, rainfall changes, and evapotranspiration
           changes that any allowance must be regarded as a "first guess."                Some have
           suggested that an allowance of about 6 millimeters per year, including the
           existing isostatic change, could be prudent for short-life structures pending
           improved estimates of the consequences of climate change. Design concepts of
           structures should ideally permit easy modification to meet longer term needs.

                 The Ministry of Agriculture, Fisheries, and Food has estimated that the
           cost of constructing a defense suitable for currently projected sea level rise
           in England and Wales could amount to between 5 and 8 billion pounds (7 and 12
           billion U.S. dollars).      Within this budget figure is an allowance for new and
           replacement pumping stations, new drainage outfall systems, and at least two new
           tide-exclusion barriers.

           Alternative Solutions

                 The opportunity for reconstructing soft defenses is diminishing. In many
           instances, this may be due to the need to provide increasingly large structures,
           the difficulty of obtaining a cheap supply of material from nearshore or inland
           sources, or the need to avoid damage caused to the environment by digging "borrow
           pits."    Similarly, hard defenses are becoming more expensive, costing 3 to
           5 million pounds per kilometer. With an appreciation of the damage that the hard
           structure can cause to the environment, there is a gradual change in the
           engineering attitudes toward seeking equally efficient alternative solutions.

                 Engineers in Great Britain are gaining experience with schemes that involve
           raising beach levels using material dredged from sources in stable, offshore
           zones. The specification for this material is usually for a coarser grading than
           that already on the beach; thus, longer term stability is anticipated.                This
           material may be further stabilized and protected by the construction of large
           terminal groins built from imported rock.



                                                      275








               North and West Europe

                    The design of these structures is complex.       A core of lighter weight
               material is protected by layers of rock of increasing mass.       Further, in an
               attempt to overcome the adverse effect associated with -terminal structures, the
               "plan shape" is built to resemble a "fish tail," and it may be curvilinear on
               plan; the crest level at the seaward end may be higher than that at the landward
               connection to encourage the littoral drift processes (Barber, 1988).

                    Thus, if the "soft" solutions being constructed to date are shown to be
               reasonably stable, we may see an extension of this engineering concept for future
               capital schemes.   In engineering terms, the choice of this solution is sound,
               and it really only represents a reversal of natural trends through the use of
               energy-dissipating structures.

                    A natural feature to which much attention is being paid is the salt marshes
               found frequently to the seaward side of defenses. These marshes are often found
               at a level of about high spring tide.       In addition to their environmental
               benefits, they are able to dissipate wave energy and allow only small, depth-
               limited waves to reach the defense structure.

                    Many of these marches are in decline because the seaward edge is being
               eroded or the vegetative cover is dying back, thus leaving only mud patches.
               Engineering solutions are being sought to reverse these trends so as to preserve
               these valuable components of a defense system.

                    The behavior and performance of marshes outline in other recent papers
               (e.g., Titus, 1988) confirms that experienced in the United Kingdom. There is
               a need, therefore, for an international approach to optimize the ability of this
               natural type of defense to respond to future sea level rise.


               RESEARCH

               Bodies Commissioning Research

                    The National Rivers Authority is continuing research previously carried
               out by water authorities and will be expanding its program to complement research
               already undertaken by the Ministry of Agriculture, Fisheries, and Food. Other
               complementary research is commissioned by organizations such as the oil industry,
               firms of consulting engineers, or intergovernmental agencies in conjunction with
               other government departments using research facilities at the numerous
               universities, research laboratories, and specialist consultants.

                    One area of research of specific interest to the National Rivers Authority
               is the work undertaken by the Ministry of Agriculture, Fisheries, and Food on
               the collection and analysis of tidal data from its system of tidal gauges around
               the coast of the United Kingdom (Figure 5). Data from some of these gauges are
               used in connection with the Storm Tide Warning Service (see the following
               section).   The program of analysis feeds into other worldwide scientific
               programs.


                                                     276







                                                                                                                    Whittle





                                                                                       LERWICK (89)






                                                                          ft



                                                            SCRABSTER
                                                                          wiCK
                                          TORHOWAY

                                                            ULLAPOOL






                                                                                 ABERDEEN



                                           OBER ORY




                                                               M.ILLPORT LEITH (88



                                                                                     NORTH SHIELOS
                                          LqAT.f&ILRICK (59)             qU1t1LRLA (90)
                                                                                           WHITBY (59)
                                                   ISLE OF.M4(00) HEYSHAM

                                                                   HILBRE           immiHGHAM
                                                    HOLYHEAD              LI ERPOOL (99)

                                                                                                          CROMER (961


                                                                                                             LOWESTOFT


                                              FISHGUARD (68)                                               FELIXSTOWE (55)
                                                                   MUMBLES (56)
                                                                            AVONMOUTH      TILBURY     SHE RNESS
                                                       ILFRACOMB          HIEKLEY (891                      OVER
                                                                                        PORTSMOUTH
                                                                                                  EWHAVEN
                                                                 OEVOHPORT     ORTLAND           BRIGHTON (90)

                                              NEWLY

                                                ST MARYS


                  Figure 5.        Tide gauges of the national network                    December 1988 (modernized
                  installations are underlined).

                                                                      277







               North and West Europe

                     Another strategic research effort is being directed toward finding ways in
               which existing defenses can be modified to improve their effectiveness.           The
               findings from this program are equally important when considering designs for
               new defenses. At present, there is much uncertainty about both the timing and
               the extent of sea level rise. Until some of these uncertainties are removed,
               it is prudent to build defenses to deal only with known situations but, equally
               so, to build in provisions for easy modification when the need arises.

               Research Programs

                     For many years, the Ministry   of Agriculture, Fisheries, and Food has been
               funding applied research and development programs. The principal areas of marine
               research have centered around the interaction of tides, surges, and waves. These
               dynamic forces have effects on sediment transport processes which greatly affect
               the foreshore, surf zone, and stability of estuaries. Many other aspects of the
               program are set out in the annual report (MAFF, 1988).

                     The former water authorities and now the National Rivers Authority also
               undertake complementary research programs.         At present, the Authority is
               concerned with developmental research into the performance of embankments. The
               Authority will also include some research into the use of new materials and
               systems to facilitate a rapid response to be made to structures should the need
               arise.



               STORM TIDE FORECAST SERVICES

               East Coast Storm Tide Warning Service

                     Following the 1953 storm event, the government set up a review committee
               to report on the event and to make recommendations.         The Waverley Committee
               recommended the establishment of a warning service for the east coast. Today,
               the service is administered by the Ministry of Agriculture, Fisheries, and Food
               and is run from the United Kingdom's Met Office.

                     Atmospheric and tidal data are fed into a numerical surge model to provide
               hourly sea level forecasts up to 36 hours ahead.     If it appears that a critical
               level could be reached at any of the reference ports (Figure 6), checks are made
               about 12 hours before high water, using real-time tidal and wind data.           This
               critical level, known as Danger Level, is predetermined and related to some
               crucial defense within the relevant Division.          The Met Office will issue
               preliminary warning notices to the relevant police force, the National Rivers
               Authority region, the local authorities, the Ministry of Agriculture, Fisheries,
               and Food, and other interested parties during this period, and it will issue a
               metric confirmation or cancellation of that preliminary warning some 4 hours
               before expected high water.

                     The National Rivers Authority will open up its relevant flood control
               center, either upon receiving a warning or whenever it perceives that
               meteorological conditions could lead to a storm. The Authority has access not
               only to this principal tidal gauge network but also to local gauges, and it will
               monitor all of these as part of its flood forecasting procedure.

                                                       278








                                                                 C%                                          EAST COAST
                                                                   0
                                                                 101P              STORM TIDE WARNING SERVICE
                                                                   0 1P                                        Police
                                         NORTHUMBRIA
                               ,-'@,NORTHUMIIIIRIAN                                                            Boundaries
                                                                                                               Force                          01011"
                                                                                                               H.Q.

                                                                                                               National Rivers' Authority
                                                                                                               Boundary
                                                                                                                   Ion                       ANGLIAN
                                               DURHAM                                                          :."Clonal H.O.              P      , 0
                                                                                                               Recelving Come
                                                             CL. E    0                                        coastal owon Boundary
                                                                                                               Port With t1do q#UQ@
                                                                                                      C%
                                                                                                     1-0
                                                  NORTH YORKSHIRE

                                                     YORKSHIRE.                                           0


                                                                           HUMBERSIDE


                                               WEST YORKSHIRE



                                                       OUT YORK IRE




                                                                                 0 Lb..h



                                                                              LINCOLNSHIRE



                                                                                                                                                0
                                                                                                     -0@     NORFOLK
                                                                                                                          0 N.-ich
                                         SEVERN -TRENT                                          ANGLIAN
                                                                                       O*Pa.b                                         -      Z

                                                                                      CAMBRIDGESHIRE
                                                                                      .0...                   SUFFOLK



                                                                                                        ESS

                                                                                                                             COASTALI
                                                                 THAMES              METROPOLITAN                          DIVISION 51

                                                                                           T
                                                                                                            Wd@                        V
                                                                                                                                       I ;
                                                                                                                                       49 0
                                                                                                           K I N T

                                                                                                                                     0 -
                                                                                                                                    0
                                                                                      SOUTHERN                                         4(@

                                                                                     www"





                                                                                           Mass
                                                                                    30    10



                            @W"             C-",W@     INM FU AD" M"F                                                            CUKIDOWM    cc-c"wio"I"s

                Figure 6. The Storm Tide Warning Service and the east coast reference ports.

                                                                                         279









             North and West Europe

                  Throughout any event, the Authority maintains close liaison with the police
             forces and local emergency services and others as needed. The National Rivers
             Authority work force and other private and public work forces, including military
             personnel, may be called on in an extreme event.     The police, as the law and
             order enforcement agency, will, in liaison with the National Rivers Authority,
             issue any notice to the public.     They will coordinate the evacuation of the
             public from any threatened zone. Following any event that entailed the issuance
             of a warning, there is an intense inquiry both to validate the quality of the
             warning and, if necessary, to evaluate the return period of the event.

                  The performance of the warning service has been progressively improving.
             This has been made possible by the new computers that can handle greater inputs
             of data; by improvements funded by the Ministry of Agriculture, Fisheries, and
             Food to the data-gathering systems at the tidal gauges; and by modifications to
             the numerical models. The detailed analysis of the tidal data is undertaken by
             the Proudman Oceanographic Laboratory at Bidston, near Liverpool, under contract
             to the Ministry of Agriculture, Fisheries, and Food.

                  The warning service outlined above applies only to the east coast.        The
             remainder of England and Wales receives only the output from the numerical surge
             model on a twice-daily basis.    A full warning system depends on refining the
             models for the south and west coasts and on having better real-time data from
             the eastern Atlantic and Western Approaches to the United Kingdom. Much of these
             data are exchanged with similar agencies on the Continent, thus ensuring their
             optimum use within international forecasting systems.


             SUMMARY

                  Land in England and Wales lying less than 5 meters above sea level must be
             protected from flooding.    Some of this land is below the sea level and has to
             be pump drained. In the main, this low-lying land is backed by a scarp-face,
             with land rising rapidly up to the +10.0 meter contour. Much of the lowest lying
             land is used for agricultural production, but the higher ridges have been
             developed for urban, commercial, and industrial use.

                  A rise in sea level will necessitate a review of present defense design
             standards. In the absence of a definitive statement on timing or amount of rise,
             designers in the National Rivers Authority are contemplating increasing the
             defense allowances and are adopting designs that are flexible enough to permit
             easy modification.    Through close contact with research bodies, the National
             Rivers Authority will develop strategies appropriate to the needs to meet
             changing circumstances.

                  It has been suggested that defenses that may have only a short life,
             approximately 25-50 years, be designed to incorporate an allowance of not less
             than 6 millimeters per year, which includes 3 millimeters per year for the
             isostatic movement in southeast England (Figure 7) (Whittle, 1989).



                                                    280











                                                                                                                                       Whittle






                                        4.0 -


                                                                       6mm/year
                                                                       High
                                        3.5                .........   Medium

                                                           - - -       Low




                                        3.0







                                        2.5






                                        2.0


                                                    Suggested maximum design
                                 >                     life for new structures
                                .2      1.5            based upon a constant
                                                              allowance





                                        1.0-






                                        0.5






                                           0

                                                  2000                           2060                           2100


                                                                                 Year



                Figure 7.           Range of predictions for an east coast port and compared to an
               allowance of 6 mm per year.

                                                                               281









               North and West Europe

                    Options for raising defenses should not be implemented unless they are cost
               effective. Decisions, however unpalatable, may have to be taken not to
               reconstruct some defenses. Present-day solutions favor the environment by
               artificially raising the beach levels. The evaluation of benefits for coastal
               defense includes components for environmental, recreational, and amenity
               benefits. -It may be appropriate to include within the benefits assessment those
               benefits that will accrue to planned future development, so that developers are
               prepared to make appropriate contributions.

                    Research into climate change, global warming, and sea level rise is
               essential to develop financially sound defense and land drainage strategies.
               The National Rivers Authority is conducting research on the use of newer
               materials and new proprietary systems to protect defenses.


               ACKNOWLEDGMENT

                    The author acknowledges the assistance given by colleagues in the National
               Rivers Authority and the Ministry of Agriculture, Fisheries, and Food in the
               preparation of this paper, and the permission of the Ministry to use material
               assembled by the author while employed there as Chief Engineer.             The views
               expressed are those of the author and do not represent the views of the Ministry
               of Agriculture, Fisheries, and Food or of the National Rivers Authority.


               BIBLIOGRAPHY

               Brunsden, D., E. Gardner, and A. Goudie A. 1989. Landshapes. London: David
               and Charles.

               Barber, P. 1988. Sea Defense at Jaywick. Report to Anglian Region, National
               Rivers Authority.

               Halcrow, Sir William and Partners.       1989.   Report on Coastal Management for
               Anglian Region. London, England: National Rivers Authority.

               Kelly, P.M.   1989.   Global Warming and the Thames Barrier.        London, England:
               London Emergency Planning Information Center, University of East Anglia.

               MAFF. 1988. Ministry of Agriculture, Fisheries, and Food. River and Coastal
               Engineering Report. London, England: MAFF.

               Titus, J.G., ed. 1988. Greenhouse Effect, Sea Level Rise, and Coastal Wetlands.
               Washington, DC: U.S. Environmental Protection Agency.

               Whittle, I.R.   1989.   The Greenhouse Effect:      London at Risk.    Conference of
               River and Coastal Engineers.     Loughborough, England: Ministry of Agriculture,
               Fisheries, and Food.



                                                        282










                   POLICY ANALYSES OF SEA LEVEL RISE IN THE
                                         NETHERLANDS



                                          J. G. DE RONDE
                           Ministry of Transport and Public Works
                           Rijkswaterstaat, Tidal Waters Division
                              P.O. Box 20907. 2500 EX Den Haag
                                         The Netherlands






          INTRODUCTION

               In the Netherlands, politicians are becoming more and more aware of the
          potential problems that could be caused by climate change. Rijkswaterstaat, a
          part of the Ministry of Public Works and Transport, started some smaller studies
          on this topic in 1985 (De Ronde, 1989; De Ronde and De Ruijter, 1986).


          THE COASTAL PROTECTION STUDY

               In 1989, an extensive policy analysis was completed on the future management
          of our sandy coast with regard to present erosion problems and the expected
          increase in sea level rise (Rijkswaterstaat, 1989). The analysis was based on
          morphological predictions of coastal development (erosion and accretion) for
          every kilometer of the 254-km length of our dune coast. The total length of the
          Dutch coast without estuaries is 353 km. The predictions were made for the years
          2000, 2020, and 2090 for three scenarios:

               Scenario A   --   present sea level rise of 20 cm per century,
               Scenario B        sea level rise of 60 cm, and
               Scenario C        sea level rise of 60 cm plus an increased wind velocity
                                 of 10%.

               Impacts like loss of safety and loss of (dune) area were compared with such
          measures as beach nourishment, groins, and dikes. An inventory was made of the
          whole coastline with a width of 500 m, and this was entered into a GIS system.
          The grid used was 1,000 by 50 m; the 50 m was perpendicular to the coastline.
          The predictions of coastal erosion/accretion together with the GIS system could
          be visualized, and totals could be made of lost areas.         The areas can be
          subdivided into different types, such as nature, nature with a high ecological
          value, housing, industry, and areas used for drinking water.


                                                 283









              North and West Europe

                   Figure 1 gives an example of the results, showing the predicted total losses
              of dune area in hectares up to the year 2090. The lower line depicts the
              predicted losses if the present sea level rise of 20 cm per century were to
              continue, and the upper line depicts the predicted losses if the expected sea
              level rise of 60 cm up to 2090 were to occur. In the case of scenario C, the
              lost area in 2090 is expected to be about 5,000 hectares. It can be concluded
              from these predictions that, in the case of the sandy coast of the Netherlands,
              the expected future sea level rise is worsening the erosion problems, but present
              erosion is the main problem.










                         hectares


                                            LOST DUNE AREA
                                                                                 0,6 meter

                    3000
                                                                       .01
                                                                      .-0

                                                                  .00

                                                                                0.1
                    2000                                  de .' .0e oo'          0,2 meter
                                                 le J-0   .00,

                                                      oe


                                            01 op
                    1000--                 loe






                             A
                       1990  2000         2020                                   2090
                                                     YEAR


              Figure 1. Predicted loss of dune area up to 2090 in the case of present sea
              level rise of 20 cm per century (scenario A) and in the case of the expected sea
              level rise of 60 cm for the next 100 years (scenario B).

                                                     284











                                                                                 De Ronde

              It is believed that present sea level rise is only a minor cause of this
         present erosion.    It is thought that this erosion is partly a late coastal
         response to more severe sea level rise in the past and partly due to sediment
         moving from the coqst into the estuaries.

              Concerning dikes, the story is of course different. Here, present problems
         consist of just maintenance plus minor adaptations, while in the case of future
         sea level rise, the necessary adaptations are much greater.

              The length of dune coast where measures like beach nourishment are
         necessary, in the case of scenarios A and B, can be found in Figure 2.         The
         large increase in the beginning is due to the fact that up to 1990, many beaches
         already will have  been nourished. So in 1990, the length of "unsafe" dunes is
         zero. If nothing is done, this length will increase rapidly in the beginning
         until the effect of past nourishments will have been diminished after roughly
         10 years. At present, about 15 km of beach needs to be kept in place by beach
         nourishment.   This area will increase to 45, 60, or 80 km (of a total of 254
         km) up to 2090 for scenarios A, B, and C. At other parts of the coast, where
         safety is not at stake, erosion will still occur.

         Future Policies

              During the coming year, politicians will have to decide what kind of policy
         will be followed in the near future.     This study describes and compares four
         possible future policies:

              ï¿½   RETREAT -- At all places where safety is not a problem, nothing will
                  done, and these parts of the coastline may retreat. Everywhere where
                  safety is at stake, the coast will be defended.

              ï¿½   SELECTIVE DEFENSE -- In addition to the actions described above, the
                  most valuable areas (e.g., dunes with a high ecological value) will also
                  be defended as well.


              ï¿½   TOTAL DEFENSE -- No retreat at all will be tolerated.

              ï¿½   SEAWARD DEFENSE -- "Weak parts of the coast" will be strengthened.

              Examples of the necessary measures for retreat and selective defense are
         shown in Figure 3. Here the planned beach nourishments are given over the period
         1990-2000 in the case of present sea level rise of 20 cm per century.

              The expected costs for the four possible policies over the coming 10 years
         are given in Table 1. Especially during the first 10 years, seaward defense is
         very expensive.   The "cheapest" policy is, of course, retreat.    The costs for
         scenario B are nearly the same as those for scenario A. For scenario C, the
         costs are again a lot higher, due to the 10% increase of the wind, with great
         effect on dike height and dune strength.     In the long run, however, seaward
         defense is only a bit more expensive than the other policies. In the case of


                                                285








             North and West Europe

                                kilometers


                            so..
                            701, -            UNSAFE DUNE COAqT

                            so..                                              0.6 meter



                            50..


                                                                              0.2 moteir
                            40--



                            30--



                            20--



                            JO..




                                                                                   A
                              1990 2000     2020                              2090

                                                      YEAR
             Figure 2. Predicted length of unsafe dune coast in the case of present sea level
             rise of 20 cm per century (scenario A) and in the case of the expected sea level
             rise of 60 cm for the next 100 years (scenario B).
                  N   Wadden                             N   Wadden

                    z@              Central                                Central
                                    Coast                                  Coast





                 Delta                                  Delta













                                                  A                                      B
             Figure 3.   Parts of the coast where beach nourishments are planned during     the
             period 1990-2000 with policy RETREAT (A) and with policy SELECTIVE DEFENSE     (B)
                                sent sea level
             in the case of pre                rise.

                                                    286








                                                                                     De Ronde

         Tabl e 1. The Expected Costs Over the Comi ng 10 Years for Four Pol i ci es and Three
                   Scenarios (millions of U.S. dollars per year)


                                                Sea level rise scenario:
                                           A                 B                 C
                                        20 cm             60 cm             85 cm
                  Policy                                                (plus 10% wind)


                 Retreat                 15                 17                 26

                 Selective
                  defense                19                 20                 31

                 Total
                  defense                25                 28                 43

                 Seaward
                  defense                30                 33                 55



         a sea level rise  of 20 cm per century, the average    costs over 100 years are 16,
         18, 21, and 23     million U.S. dollars per year,      respectively, for the four
         policies.

                 The Minister of Transport and Public Works recently advised policy makers
         to use the policy of total defense.


         THE ISOS STUDY

                 Another policy analysis will be finished at the beginning of 1990. This
         so-called Impact of Sea Level Rise on Society (ISOS) study is being conducted
         in cooperation with the United Nations Environment Programme and Delft
         Hydraulics.

                 This study focuses on the impacts of and possible responses to sea level
         rise.   It also examines other effects of climate change, including shifts in
         storms, river discharges, precipitation, and evapotranspiration.          Storms may
         become more severe or more frequent, having great consequences for the design
         of coastal structures. River discharges may increase and cause more frequent
         flooding during the winter season, or may decrease during summer and cause
         shortages of water needed for agriculture or drinking. These impacts and the
         possible measures against them will also be studied, but more along the lines
         of a sensitivity analysis.

                 The ISOS study will include the entire Netherlands. Besides the coast,
         it will look at 3,000 km of dikes along estuaries, rivers, and lakes. Further,



                                                  287








               North and West Europe

               it will analyze the impacts of sea level rise on the ecology and water management
               of the Netherlands. Table 2 shows some of the scenarios that will be used in
               this study.

                      Of course, looking at only impacts is insufficient when discussing sea
               level rise. Equally (or even more) important are the possible measures to be
               taken and when they should be taken.


               Table 2. Main Scenarios of the ISOS Study         Changes Between 1990 and 2090


                                           Favorable             Mean           Unfavorable
                                           Scenario           Scenario            Scenario
                         Parameter             A                   B                 C



                     Mean sea level rise    + 35 cm           +  60 cm            + 85-cm

                     Wind force             - 10%                0%               + 10%

                     Wind direction         - 100                00               + 100

                     Mean rise of design
                       level                - 20  cm          +  65 cm            + 150 cm

                     Precipitation
                         Summer             + 20%             +  10%                  0%
                         Winter                0%             +  10%              + 20%

                     Evapotranspiration
                         Summer             +  0%             +  10%              +*20%
                         Winter             +  0%             +  10%              + 20%

                     River discharge
                         Summer             +  10%                0%              - 10%
                         Winter             -  10%            +   0%              + 10%



                    First of all, impacts with the so-called To alternative (no measures taken)
               will have to be quantified, starting with the changes in hydraulic conditions;
               the effects on morphology; and the consequences for safety, water management,
               environmental management, and costs. With this knowledge, alternative measures
               and constructions can be designed. Given a certain measure or set of measures,
               the impacts on hydraulic conditions, morphology, etc., must be studied.          When
               this has been done, the different alternatives can be evaluated and compared.

                   With the ISOS study for the Netherlands, it will be possible to answer
               questions such as the following:


                                                       288











                                                                                     De Ronde

               ï¿½  Depending on the rate of acceleration of sea level rise, what measures
                  should be taken, and when should we initiate them? (or: How long can we
                  wait before we have to do something?)

               ï¿½  If not only relative sea level rise is changing, but also storm
                  frequency as well as river discharges, then how important are the
                  various impacts compared to each other? In other words, should we not
                  be as worried about these other changes   as we are about sea level rise?
                  For example, in the case of the Dutch      coast, a 10% increase in wind
                  force has about the same influence as a 60-cm rise in sea level.

               The results of the first phase of the ISOS study, with an inventory of all
          important relations between -- on the one hand -- sea level rise, changes of
          storm surges, and changes of river discharges, and -- on the other hand -- the
          impacts, were published in 1988 (Rijkswaterstaat and Delft Hydraulics, 1988).
          The second phase of the study is not yet finished.             Here, though, some
          preliminary results will be given for dikes only.

               The 3,000 km of primary dikes in the Netherlands were divided into about 50
          so-called dike-rings, each with its own safety standard and subdivided into
          about 150 dike-parts.     For each dike-part, cost functions were calculated,
          depending on the amount of heightening of the dike, the dike's construction, and
          the extension of buildings along and on the dike. The raising of a dike within
          a town with many houses in and on the dike is many times more expensive than the
          raising of a simple dike in the countryside. On the other hand, the model can
          calculate for every dike-part the necessary raising, depending on sea level rise,
          changes in storminess, changes in river discharges, and changes in management
          (e.g., the management of the IJssel Lake).

               In the case of the expected sea level rise of 60 cm for the coming 100
          years, total costs for dikes will amount to about $7.5 billion U.S. dollars
          (Figure 4).   In the case of the unfavorable scenario, where besides the 60-cm
          sea level rise an increase of the wind of 10% and an increase of winter river
          discharges of 10% were considered, the total costs increase to $14 billion U.S.
          dollars.

               Within the model, the number of dike heightenings during the coming 100
          years and the amount of heightening can be differed. When the dikes are raised
          in small steps, the costs will be incurred as late as possible in time, but the
          total costs will be greater because of the initial costs that occur at every step
          of raising. On the other hand, when they are raised in one or two big steps,
          the initial costs will occur only once or twice, but the relatively high costs
          of the first raising will occur early in the heightening.          These different
          strategies can be worked out with the model, and an optimal strategy can be
          found.

               Given a certain scenario (e.g., 60-cm sea level rise), finding an optimal
          strategy will not be difficult. The target in the ISOS study will be to find
          an optimal strategy, given all possible scenarios with their chance of


                                                  289









                North and West Europe







                              INTEGRATED COSTS OF DIXE RAISING         NEDERL-T


                                  SCE: ONG       MSR: STRATEGO
                                  SCE: Zfia      MSR: STRATEGS





                                    2.90





                                    2.10





                                    1.40
                             q4











                                        ji

                                       .00        .20       .40        .68        .88       1.00

                                                                               2
                                                     t irn ei, nyears X (10


                          1 IPOSZ 1.00                 4elft h9draulics (c)



               Figure 4.     Integrated costs of dike raising for the scenarios.            Expected sea
               level rise   of 60 cm and the unfavorable scenario with 85-cm sea level rise plus
               10% wind and 10% river discharge.

                                                            290











                                                                                        De Ronde

         occurrence. This will be much more difficult. On the one hand, one will try
         to minimize the chance of being in an unsafe situation (when real changes will
         be greater than expected), while on the other hand, extensive measures might be
         overdone when changes will be smaller than expected.


         BIBLIOGRAPHY

         De Ronde, J.G. and W.P.M. De Ruijter, eds. 1986. Zeespiegelrijzing, worstelen
         met wassend water.         Report GWAO-86.002.        The Hague, the Netherlands:
         Rijkswaterstaat, Tidal Waters Division (in Dutch).

         De Ronde, J.G.      1989.    Past and future sea level rise in the Netherlands,
         Proceedings of the Workshop on Sea Level Rise and Coastal Processes, Florida,
         March 9-11, 1989.

         Rijkswaterstaat and Delft Hydraulics.         1988.    Impact of Sea Level Rise on
         Society: A Case Study for the Netherlands, phase I. The Hague, The Netherlands:
         Rijkswaterstaat.

         Rijkswaterstaat. 1989. Kustverdediging na 1990, discussienota.            (In Dutch, an
         English version of this report will appear in 1990.)

























                                                    291











       IMPACTS OF AND RESPONSES TO SEA LEVEL RISE IN PORTUGAL



                         MARIA EUGENIA S. DE ALBERGARIA MOREIRA
                               Centro de Estudos Geograficos
                                    University of Lisbon
                                       Lisbon, Portugal






        ABSTRACT

             Because of the physiographic characteristics of the Portuguese coast and its
        population distribution, the main potential impacts of sea level rise will occur
        in the estuaries and coastal lagoons, on the barrier islands, and along the
        active sandstone cliffs.    The large estuaries and coastal lagoon systems will
        be the most severely affected areas because they are densely populated and are
        the sites of extensive economic activity.     Approximately 70% to 95% of their
        intertidal areas, 0.5 m to 2.0 m in elevation, are reclaimed or used in their
        natural capacity. These reclaimed lands are occupied by salines (salt pans) and
        aquacultural ponds (40%), agricultural fields (34%, primarily rice) associated
        with extensive pasture land (2%), port development (12%), urban and industrial
        development (8%), and airports (1%).

             Among the impacts already being observed as a result of sea level rise are
        damage to    several artificial coastal structures, beach erosion, retreat of
        sandstone cliffs, salt marsh retreat, and salinization of the reclaimed
        agricultural soils.     The first two and the last of these impacts require
        immediate responses from the responsible central and local government agencies.

             Wherever harbors and tourist beaches are affected by erosion, the
        institutional reaction has been, and will be in the near future, to rely on
        technology to repair or reinforce the existing development.

             Regarding the impacts on the agricultural soils (rice fields), the responses
        of the agencies to the current situation have been to build freshwater reservoirs
        along the freshwater fluvial systems to assist in flushing the fields. Future
        responses to the increasing salinity in the soils and in the water table, and
        also to the submergence (up to 2 m), will need to be different from current
        responses.   The initial reaction by central governmental bodies to the soil
        salinization probably will be to shift the main crop from rice to more salt-
        tolerant plants (e.g., barley or sugarbeets), or more probably to shift the use
        of these reclaimed areas from agriculture to some sort of development. At the


                                               293









             North and West Europe

             municipal level, agencies will probably rely on technological improvements and
             will continue to produce rice.


             INTRODUCTION

                 This paper briefly lays out the climate, hydrology, and coastal
             geomorphology of Portugal .   It then discusses potential impacts of sea level
             rise and summarizes our discussions with officials of Portuguese agencies that
             must respond to sea level rise.

             Climate and Hydrology

                 The Portuguese coast is in the subtropics, on the boundary between the
             Atlantic temperate climate and the Mediterranean climate (Figure 1).         This
             geographical position explains the different climate regimes that can be found
             along the coast, which contributes to the different local geomorphological
             processes.                                I

                 All of the western coast is exposed to the influence of the Westerlies that
             dominate the annual and the seasonal wind      regime blowing from the north,
             northwest, and west. Strong storm winds blow from the southwest in the winter,
             associated with tropical depressions.

                 Wave heights vary: the annual mean wave     height is 2.9 m on the northern
             sector (Leixoes), 2.3 m on the central sector  from Aveiro to Cabo da Roca, 1.0
             m on the southwestern sector, and 1.1-1.4 m on the southern coast of the Algarve



                                                                                            C.-

                        Xw





                                            - - ---------                                . .........


                                                                                   ---------------------- dd@-

                                                                                             20-






             ... ........




                                                             .........................






             Figure 1. Location of   Portugal in the subtropical zone.

                                                    294











                                                                                        Moreira

           (Figure 2).    The greatest wave heights, observed in Sines on the           western
           Portuguese coast in 1978, were around 16-17 m; they originated from the southwest
           during a 100-year storm that destroyed the jetties of the harbor of Sines (Feio,
           1980). On the southern coast, the calm seas dominate and the infrequent high
           waves very seldom reach 5 m. They occur when the strong Levante wind blows from
           the Gulf of Gibraltar, usually in winter but also in spring or in autumn.

                On the western coast, calm seas   (wave height less than I m) are infrequent,
           as are extreme storm waves (higher than 6 m, Figure 2). The storm waves do not
           occur every year, but they are more frequent in the northern region, occurring
           every winter.

                As a consequence of the wave regime, a general longshore current is
           generated from north to south on the western coast (Ferreira, 1981; Ribeiro et
           al., 1987).   Deflected and refracted by the capes, the current can reach the
           coast from opposite directions, from the west, the west-southwest, and the
           southwest.   A strong littoral current from the southwest also occurs when the
           waves run from the southwest.       The morphodynamic effects of both of these
           littoral transport directions can be seen on the growth and migration of the
           spits and barrier islands along all of the coast.

                The tidal regime on the Portuguese coast is semi-diurnal and mesotidal . The
           tidal range is around 3.8 m along the western coast, 3.4 m on the southern coast
           during the spring tides, and between 0.9 m and 1.2 m during neap tides.       In the
           estuaries, the tidal range is 60-80 cm higher during spring tides. In time of
           the fluvial floods, or even during the high fluvial water flow, these values can
           increase a few centimeters. The spring tide level reaches 2 m above mean sea
           level on the open coast, if the sea is calm.


           THE COASTAL GEOMORPHOLOGIC CHARACTERISTICS

                The Portuguese coast (excluding the islands) is around 870 km long and
           presents a great variety of geomorphologic features, as shown         in Figure 3.
           According to the published geomorphologic map (Ferreira, 1981) and measurements
           taken from the 1:50,000 national topographic maps, sandy beaches       occupy 37.5%
           of the total length of the coastline; coastal wetlands, 36.9%; and cliffs, 25.6%
           (Figure 3).

                Excluding the beaches located near the main estuaries, which     are nourished
           by the fluvial sediments, the beaches of the western coast are narrow (70 to 150
           m) -- even those with dunes.      The widest beaches have gentle slopes and are
           located along the spits, or on the coastal sectors sheltered from the waves by
           prominent capes.

                On the southern coast, the beaches are narrow with gentle slopes. On the
           western side, there are pocket beaches interconnecting through the karst caves
           and galleries cut into the calcareous sandstone of the cliffs. Along the eastern
           sector, there are linear beaches extending along a cliff face or in the form of
           barrier islands and barrier spits.

                                                   295









                North and West Europe

                                                                                          4 2'.

                                   Northern coast


                        JO


                        0                                     Leix8es








                                         Central Coast


                                                                                          4 0%








                                                      Peniche










                                                                                       IOOK:r



                      Southwestern Coast
                                                             S in e s                     3





                                                                              14onte Gordo
                                                              Rocha
                                N
                                 i i


                              0    10M,



                                            st
                                   to     Southern Coast      to     East Southern Coast


                                                               0 1  2 3 4 8 0

               Figure 2. Spectra of the annual mean wave directions along the Portuguese coast
               (1974-1978). Frequency distribution of the annual mean wave height. Data from
               I.N.M.G.


                                                        296










           A                                               B
                                                                                                         A W


                            RON""





                                                                             "sob-




                                                     N-
                                                                           IWM
                                        -jog

                                                       ''NAW"T

                                                                                                A



           C






                                                                  Figure 3. The coast of Portugal.

                               j
                                                                  (A)  The rocky, sourthern Algarve
                                                                  coast of Portugal.

                                                                  (B) A combination f ishing and tourist
                                                                  village on the Algarve coast.
                  .Ar







                                                                  (C) A highly-populated tourist beach
                                                                  in Nazare.

                                                                  (All photos by Karen Clemens)









              North and West Europe

                    Excluding the beaches located near the main estuaries, which are nourished
              by the fluvial sediments, the beaches of the western coast are narrow (70 to 150
              m) -- even those with dunes.       The widest beaches have gentle slopes and are
              located along the spits, or on the coastal sectors sheltered from the waves by
              prominent capes.

                    On the southern coast, the beaches are narrow with gentle slopes. On the
              western side, there are pocket beaches interconnecting through the karst caves
              and galleries cut into the calcareous sandstone of the cliffs. Along the eastern
              sector, there are linear beaches extending along a cliff face or in the form of
              barrier islands and barrier spits.

                    Most of the western Algarve beaches are almost completely submerged during
              the high spring tides. This feature and the retreat of the cliffs (Dias, 1988)
              are already serious problems to the tourist industry there.

                    The coastal wetlands include the low tidal platforms, which are sandy or
              muddy, and the upper tidal platforms covered by salt marsh vegetation. They have
              developed on the sheltered estuarine margins, along the creeks, and around the
              lagoons between 1.5 m below sea level and 2 m above sea level (Figure 3). They
              represent 70% of the total intertidal area of the Portuguese coast.

                    Approximately 70-95% of the nation's salt marshes have been reclaimed
              (Moreira, 1986).     The land is defended from tidal submergence by dikes or
              embankments.    The remaining marsh is characterized by a flat surface and is
              pocked by tidal pans and by a dense network of creeks. The microcliff of the
              vegetated salt marsh almost always shows a tendency to retreat, being undercut
              by the currents and collapsing afterwards.       The resulting silty sediments are
              accumulating on the tidal platforms where they are stabilized by the low salt-
              marsh vegetation. The platform is sandy and muddy, with layers of broken shells,
              and cut by the creeks that are more deeply excavated into the mud than into the
              sand.

                    The tidal platforms developed in the Ria Formosa (Faro) lagoonal system are
              sheltered by the barrier islands (Figure 3). They are essentially sandy, with
              layers of clay and silt (Granja, 1984), and form islands that are colonized by
              a Mediterranean type of salt marsh.       The creeks are not very deep, and their
              margins evolve mostly by the sliding of the sandy layers that overlay the silt.
              Here, as well as in Aveiro and in the Sado, the salt marsh is being covered by
              the sand coming from the transgressive dunes (on the spits and barrier islands)
              and from the beach ridges, blown by the wind, or carried by overwash events.

                    The cliffs differ in height, profile, and lithological composition (Figure
              3).   The highest cliffs (more than 50 m) are cut into hard rock, granite, and
              metamorphic rock on the northern coast, compact calcareous formations and schists
              on the southwestern coast, and interbanded limestone-mudstone-sandstone in the
              central coast, north of Serra de Sintra. They are connected to abrasive rocky
              platforms that have a lot of stacks, especially when cut into granite.             The
              processes of retreat, consisting of large rotational landslides, are evident on
              the limestone and the mudstone cliffs.

                                                       298










                                                                                            Moreira

               Low cliffs, around 10 m, also can be found cut into granite in the north,
          and into calcareous formations such as at Cabo Raso on the central portion of
          the coast.    Low cliffs, 15-20 m high, cut into the Miocene and the Pliocene
          sandstones are very frequent on the central and the southwest coast, and the
          Algarve coast between Sagres and Quarteira.            They are connected to narrow
          limestone platforms with abundant stacks and patches of sandy accumulations that
          form several pocket beaches.       These cliffs retreat by collapsing after being
          undercut at the base. Cliff retreat rates of 2 m/year due to human effects and
          a sea level rise were measured by Dias (1988).


          COASTAL LAND USE

               The coastal fringe in Portugal is largely natural. Intertidal areas and
          adjacent land within the public maritime domain are administered by the Navy and
          by the municipalities. No construction is allowed there, and even the public
          infrastructure for sanitary facilities, safety, and leisure is regulated and
          needs special authorization. These laws, the tidal range, and the annual storm
          waves of 5 m to 7 m discourage permanent human occupation of the very low coastal
          fringe. There is a strong contrast between the modest human occupation of the
          low coastal fringe and the very high population density of the coastal
          municipalities (Figure 4).

               Among the coastal natural systems, the dunes and the estuarine and lagoonal
          wetlands are the most disturbed systems due to the permanent human occupation.
          The dunes are inhabited along most of the coast, except in the natural protected
          areas that occupy 25% of the total coastal area.           Major tourist settlements
          occupy 29% of the secondary dunes, and some are even found on the primary dune
          (foredune), as occurs on the northern sandy coast and on the eastern Algarve
          coast, including the Ria Formosa barrier islands (Figure 5).

               The traditional fishing settlements, located on the beach and in the
          foredunes, are now quite scarce (4% of the dune area) because they have been
          transformed into tourist villages or modern fishing ports. The most important
          traditional fishing settlements that are permanently occupied are found on the
          barrier islands of the Algarve and are dispersed on the central coast.

               Other  artificial structures, such as harbors and military airports, have
          been built on the dune fringe (Figure 5). In general, the foredune is occupied
          by natural  vegetation that is regenerated or planted to minimize the migration
          of the sand inland. Forty-two percent of the total coastal dune area is planted
          with pines  (primarily maritime pine), acacia, and eucalyptus. The coastal dune
          areas have high concentrations of tourism, but the highest concentration of
          population  (Figure 4) is along the estuarine margins and the coastal fringe from
          Cascais to  Li sbon (the Costa do Sol , the f i rst touri st area of Portugal ) (Cavaco,
          1983).

               The coastal fringe of Alentejo, from Troia (Setubal) to Sagres, shows very
          low population densities, and some places are deserted. The sector near Sines
          is an exception, due to the industrial complex and harbor of Sines, and also to
          the increasing tourist demand on this coast.

                                                    299








                   North and West Europe





                                                                                         ::UU
                                                                       . .........










                                                                                                ;Jr












                                                      L
                                                                       ................
                                                                        ...............
                                                                        ...................
                                                                  .......................















                                                          ..........               . ........



                                                          . .. . ............



                                                                        ..............
                                                                       ................ ..








                                                        . ........ .............


                                                                                                 20-SO

                                       0          50 km                                          so-=

                                                                                                 M-200


                                                        AL.                   .... ..




                  Figure 4.          Distribution of the population density in Portugal (1981) by
                  municipality       (Concelho) (E.P.R.U., 1988).

                                                                       300










                                                                                             Moreira
                                                                                       42t




















                                                     AVEIRO





                                                  FIGUEIRA
                                                  DA FOZ





                                                        Tojo R.
                                             BIDOS




                                                                                       39t.


                                        BOA

                                                SET68AL


                     L %



                                                SAWTQ
                          3                                                           38t
                                                ANDRE


                          4


                                                                           0      100 km
                                                               CASTRO
                          6                      ALVOR          MARIM
                                                             FARO
                          7                                                           37

                 L

            Figure 5. Principal types of land use on the coastal zone: (1) planted forest
            (pinelands); (2) natural coastal shrubland; (3) urban and tourist occupation;
            (4) cultivated areas; (5) natural reserves and protected areas; (6) harbors; and
            (7) airports.

                                                      301








                North and West Europe

                     The coastal wetlands, which have developed on the intertidal platforms of
                the estuaries and lagoons (Figure 3), have been hurt by human activities more
                than any other part of the coastal zone. The salt marsh, as a natural system,
                occupies only around 10% of its original area,      where it is protected as Natural
                Reserves or Parks due to its ecological value. More than 90% of the total area
                of the salt marshes are reclaimed; of thisi 40% is totally or partly transformed
                into salt works and fish ponds.       Agri cul tural fields (especially rice fields)
                represent 34% of the land use in association        with pastures or grazing fields
                (2%).    Harbors (commercial, fisheries, and        leisure) occupy 12%; urban and
                industrial areas (8%) and airports (1%) form the remainder of the land use.

                     The salt works are on the high tida      1 mudflat, after building dikes that
                are more or less. 0.5 m to I m above the spring high tide water level.              Very
                often the dikes need to be repaired, and some of them are permanently reinforced
                by rock embankments or by wooden bulkheads that try to avoid or to minimize the
                erosive effects of the storms or the fluvial floods.

                     In most of the rice fields, the drainage water is discharged through gates
                into the estuarine deep channels during the low tides. In a very few cases is
                this drainage water pumped from the rice field drains to be discharged into the
                estuary, because the rice fields occupy the surface of the upper mudflat (1-3
                m above sea level).

                     Salinization of the rice field soils occurs in summer owing to the dryness
                of the climate (Daveau et al., 1977). This situation happens frequently on the
                southern estuaries during the dry years, when the evapotranspiration is very high
                and there is insufficient freshwater to inundate the rice fields and to reduce
                the salinity of the water table.

                     The urban and industrial areas, as well as the harbors, represent the
                highest investment on the reclaimed areas. The most important towns and harbors
                of Portugal are located on the estuarine or on the lagoonal margins, and their
                artificial structures, such as harbor platforms, roads, and railways, are 2-4
                m above sea I evel . It i s the same wi th the ai rports that were bui 1 t on the upper
                mudflat, as the airport of Faro, whose runways have cracked as the underlying
                muds settled.



                THE IMPACTS OF POTENTIAL SEA LEVEL RISE

                     Some of the impacts the Portuguese coast could suffer from sea level rise
                will affect all of the coast, independent of its morphology.           The erosion and
                submergence (partial or total) of the former intertidal area will increase, and
                the extent of other impacts will depend upon the coastal morphology, the rate
                of the sea level rise, the topography, and the resistance of the lithologic
                materials against the erosion.         Therefore, the impacts in this paper are
                presented relative to the coastal morphology, classified as estuaries and coastal
                lagoons, beaches, and cliffs.

                     In the estuaries and coastal lagoons, the consequences of a 2-m rise in sea
                level  (Figure 6c) will be the great enlargement of the estuarine area,

                                                          302










                                                                                     Moreira

           penetrating into the fluvial system; the increase of the salinity into the
           estuaries and aquifers; the salinization of the soil water table in the fluvial
           plains and in the reclaimed lowlands; the submergence of part of the salines,
           the fish ponds, and the rice fields; the submergence of the total tidal platform
           ("slikke") and the low salt marsh; the retreat and disappearance of the salt
           marsh area; a great risk of erosion and flooding of the harbors and the low
           coastal urban areas; the submergence of the Faro airport; and the increasing risk
           of flooding and backup in the urban waste drains.

                On the beaches, the main impacts will be the narrowing of the beach by
           about 50% and the retreat of the foredune; the disappearance of the pocket
           beaches; and new pocket beach formation close to the eroding sandstone cliffs.
           The Ria Formosa barrier islands will lose more than 50% of their area.         New
           inlets will form, and washover will increase.

                On the cliffs, the impacts of sea level rise will be the submergence of the
           abrasion platforms and the increasing retreat of the sandstone cliffs, of the
           limestone cliffs, and even of the hard-rock cliffs (especially in the active
           tectonic areas).

                From the listed impacts, the more important will be those affecting the
           estuaries (low coastal wetlands and estuarine waters) and the lagoons, because
           they are both the most vulnerable and the most populated.

                In the case of a sea level rise of 1 m (Figure 6B), the greatest economic
           impact will be the investment associated with coastal tourism.          The most
           important tourist beaches of the country will disappear. On the coast of the
           Algarve, this problem will be in addition to the retreat of the cliffs, whose
           tops are very often highly developed.

                For a sea level rise of 0.5 m (Figure 6A), the increased salinity of the
           estuarine waters, aquifers, and soils will be economically more important than
           the submergence of the lower tidal flats, or the erosive effects on the salt
           marsh not offset by accumulation of peat and sediment. Salinization will affect
           the freshwater supplies for domestic and industrial uses and the water table of
           the agricultural soils, especially in the rice fields. Sea level rise will also
           be costly for rice agriculture because of the need to pump drainage water from
           the rice fields before discharging it into the creeks.

                Because of the reclamation of the salt marshes, this ecosystem will not
           migrate on the inland boundaries because they are formed of dikes or very steep
           dune slopes. In some places, the dikes are less than 50 cm higher than the
           spring high tide water level. Here, the erosive effects will be considerable
           because they already are a real problem to the owners of the rice fields.


           RESPONSES TO SEA LEVEL RISE

                The responsibility for managing the coastal zone rests with several entities
           of the central, regional, and local administrative authorities.         The most
           important decisionmakers are the Navy (central administration) and the

                                                  303








              North and West Europe

              municipalities (local administration). The Department of the Environment must
              be consulted, as well as the other agencies that are related to the spatial
              organization of this zone.

                   Among the several organizations and services that take care of the coastal
              zonels protection and management are those that should be involved with the main
              problems concerning the impacts of sea level rise on the coastal lowlands. To
              some of these agencies, the impacts of sea level rise constitute surprising news,
              first because they had never considered it, and second because they thought that,
              it was not so urgent a problem.      To other agencies, the impacts are a real
              problem and they have been applying the classic engineering solutions to protect
              the coastline. We briefly summarize what officials in various agencies think
              about sea level rise.

              National Navy

                   As the coastal fringe is a public domain, the national navy is responsible
              for managing the coastal margin that occupies the space between the high spring
              tides and a line located 50 m inland.

                   The Hydrographic Institute is the Navy surveying department with an interest
              in coastal dynamics. It produces the cartography of the sea bottom and does the
              research for controlling and monitoring all the conditions related to
              navigability. The phenomenon of sea level rise is, actually, one of the research
              programs partly supported by the Institute.     Although the results demonstrate
              that sea level is rising between 1.27 mm and 1.54 mm per year (Taborda and Dias,
              1989), the consequent impacts have not been viewed as a problem. Naval officials
              generally believe that protection structures should be built.

              Municipalities

                   The response of the municipalities where tourism is the main economic source
              is to keep the beach as large as possible. They will rely on technology (coastal
              engineering structures, nourishment).     Some municipal officials suggest that
              swimming pools be built at seaside as an insurance in case beaches are lost.

              State Secretary of the Environment

                   The impacts on the natural systems will be controlled by several
              organizations connected to the environment:      the General Directorate of the
              Environment (DGA); the General Directorate of the Quality of the Environment
              (DGQA); the General Directorate of Natural       Resources (DGRN); the General
              Directorate of Hydraulic Resources (DGRH); and  the General Directorate of Parks
              and Natural Reserves (DGPRN).    These organizations, which report to the State
              Secretary of the Environment, are responsible for all aspects of environmental
              protection at this time. There is no Ministry  of the Environment currently, and
              thus there is no cabinet-level representation   for the environment in Portugal.

                   To some of these entities, the sea level  rise issue was surprising, as was
              the evidence that it could have such severe impacts on the natural coastal
              systems, as well as on the economic systems. DGQA is developing some research

                                                     304










                                                                                                                                                     poke




                                                                                                                                                 VI*

                                                                                                                            40








                                  fle"t",
                                                                                                       it.
                                            ft.
                               VEIRO                                                     At EIRO                                                      It! I



                           FIGUEIPA                                                     IGUEIRA                                                    IGUEI
                           DA rOZ                                                      DA fOZ
                                                                                                                                                  DA roz










             LISWA-                                                     L I S 1300V                                                LISOO













                                      PARO                                                      ..VAWO@



                   Figure 6. Location and             relative importance of the impacts                   of potential sea level rises o
                   m; (C) 2 m.        1, 2, and 3 - increasing erosion; 4 - submergence; 5 - salinization.







              North and West Europe

              projects about climate change due to the greenhouse effect and the consequent
              warming of the atmosphere.

                   The discussion of the impacts of sea level rise on the coastal hydraulic
              systems will continue in the near future, although these agencies have a very
              small capacity of direct intervention. Clearly, they must advise the private
              owners and other official entities about the risks of certain investments.

                   Some impacts that have been controlled are those affecting the natural parks
              and reserves (DGPRN), especially on the coastal wetlands (Natural Reserves of
              Pancas-Tejo estuary, estuary of Sado, Ria Formosa, and Castro Marin-Guadiana),
              because the salt marshes will retreat and disappear as a result of the erosion
              and the submergence. A solution that must be considered is to allow marshes to
              migrate inland, replacing the existing estuarine brackish marshes, which are
              not very extensive because of the reclamation of the low fluvial plain and the
              channelization of the river courses.

              General Directorate of Harbors

                  The potential impacts on harbors, and on other structures, of coastal
              engineering to protect beaches, such as avoiding the infilling of the estuarine
              navigation channels, monitoring the growing of the bars, and dredging, will be
              controlled by the General Directorate of Harbors (DGP).    This agency controls
              the national and regional management of the harbors and other coastal protection
              structures, according to the regional and local civil administration (Commissions
              of Regional Coordination and Municipalities).

                  This office is not very      concerned about sea level rise because the
              consequences will unfold slowly.   They need to rebuild the coastal structures
              anyway, from time to time, so sea level rise can be incorporated gradually. The
              reinforcement of structures whose effective lifetime will be decreased and the
              building of new structures are the solutions most commonly suggested.

              National Survey for Civil Protection

                  The National Survey for Civil Protection is part of the Ministry of Defense
              and protects the people against natural hazards.      It is concerned with the
              impacts of a sea level rise of I m and 2 m because    of the increased flooding
              risks in the urban drainage systems and the risk to   buildings affected by the
              storm waves.  They told us that they have no immediate answer to the problem,
              but they will,consider it.

              General Directorate of Agricultural Resources

                  The General Directorate of Agricultural Resources is responsible for the
              study of soils and the coordination of agricultural productivity.     It is very
              concerned about the problem of salinization of the reclaimed estuarine soils and
              the alluvial soils.   The subject is being studied, and several solutions and
              their economic feasibility are being considered, especially because of the
              potential for decreased rice productivity. At the same time, the cost of rice
              production will increase because of the cost of energy to pump the water from

                                                    306










                                                                                           Moreira

           the drainage channels of the rice fields. One of the possible solutions may be
           to substitute other crops (oats, barley, or sugarbeets) for rice or to use the
           land for purposes other than agriculture.

           General Directorate of Tourism

                The Directorate of Tourism is one of the organizations connected to coastal
           management and planning.      It is very concerned with the impacts of sea level
           rise on the coast, mostly on the beaches. Together with other agencies, it will
           try to find options that can provide practical solutions, such as jetties or
           artificial nourishment of the beach. A proposed solution to decrease the tourist
           pressure on the coastal fringe will be accepted with very great difficulty.

                The impacts of the possible sea level rise will be controlled by several of
           these organizations as well as by the owners of the land. Very seldom will such
           impacts be responded to by only one agency.


           CONCLUSION

                One of the few conclusions we are able to draw is that the solutions will
           appear gradually as sea level rises. Neither structural solutions nor land use
           changes are yet part of the planning process in Portugal.             This is hardly
           surprising given the recent nature of the issue. Nevertheless, because sea level
           rise could have important impacts, the time to start planning is now.


           BIBLIOGRAPHY

           Cavaco, C.    1983.  A Costa do Estoril.     Esboco Geografico.     Ciencia e Tecnica
           6, Lisboa, Ed. Progresso Social e Demografia:261.

           Carvalho, J.R.R., and J.P. Barcelo. 1966. Agitacao maritima na Costa Oeste de
           Portugal Metropolitano. Lisboa, Laboratorio Nacional de Engenharia Civil, Mem.
           290:63.

           Daveau, S. , et al. 1977. Repartition et rythme des precipitations au Portugal.
           Lisboa, Centro de Estudos Geograficos, Mem. 3:184.

           Dias, J.M.A.   1988. Aspectos geologicos do Litoral Algario. Geonovas, 10:113-
           128.

           E.P.R.U.    1988.    Portugal em Mapas e Numeros.        Lisboa, Centro de Estudos
           Geograficos, Rel. 28.

           Feio, M. 1980. 0 Porto de Sines: prejuizos e reparacoes. Finisterra 15(29):74-
           84.

           Ferreira, D.B.    1981.   Carte Geomorphologique du Portugal.       Lisboa, Centro de
           Estudos Geograficos, Mem. 6.


                                                     307








               North and West Europe

               Granja, H.M. 1984. Etude geomorphologique, sedimentologique et geochimique de
               la Ria Formosa (Portugal). These de 3, troisiemme cycle, Univ. Bordeaux 1:254.

               Instituto Hidrografico.      1978, 1988.     Tabel a de Mares, 1979 and 1989 - 1,
               Portugal, Lisboa.

               Instituto Nacional de Meteorologia e Geofisica.                1974-1978.       Anuario
               Climatologico de Portugal, Lisboa, 1974, 1975, 1976, 1977, and 1978.

               Moreira, M.E.S.A.     1986.    Man made disturbances of Portuguese salt-marshes.
               Thalassas 4(l):43-47.

               Moreira, M.E.S.A. 1989. Geomorphology and sedimentation rates of the tidal mud
               flats of the Sado estuary. IGU-CCE Annual Regional Symposium Guide Book, Lisboa,
               130 p.

               Psuty, N.P. 1986. Impact of impending sea-level rise scenarios: the New Jersey
               barrier island responses. Bull. New Jersey Academy of Science 31(2):29-36.

               Ribeiro, 0., H. Lautensach, and S. Daveau. 1987. Geografia de Portugal I. A
               Posicao Geografica e o Territorio. Lisboa: Sada Costa, 334 p.

               Servico Meteorologico Nacional. 1970. 0 Clima de Portugal. Fasciculo XII -
               Normais climatologicas do Continente, Acores e Madeira, correspondentes a 1931-
               1960, Lisboa.

               Taborda, R., and J.M.A. Dias. 1989. Tide-gauge data in deducing sea level rise
               and crustal movements rate: the Portuguese case.            IGU-CCE Annual Regional
               Symposium Guide Book, Lisboa. 130 p.

               Titus, J.G.     1986.    Greenhouse effect, sea level rise, and coastal zone
               management. Coastal Zone Management Journal 14(3):147-171.


















                                                        308























              CENTRAL AND SOUTH AMERICA











            POTENTIAL IMPACTS OF SEA LEVEL RISE ON THE COAST
                                          OF BRAZIL



                                        DIETER MUEHE
                                 Departamento de Geografia
                                  Instituto de Geociencias
                         Universidade Federal do Rio de Janeiro
                             Rio de Janeiro, RJ 21945, Brazil

                                       CLAUDIO F. NEVES
                         Programa de Engenharia Oceanica, Coppe
                         Universidade Federal do Rio de Janeiro
                                      Caixa Postal 68508
                             Rio de Janeiro, RJ 21945, Brazil




         EXECUTIVE SUMMARY

             The impact of sea level rise on Brazil would be similar to the impacts on
         other nations: Wetlands and lowlands would be inundated, beaches would erode,
         coastal areas would flood more frequently, and saltwater would encroach inland.
         But the question remains: How severe will the effects be, how much will they
         cost, and what should we do?

             Because Brazilians have only recently begun to ask these questions and
         almost no research has been done to answer them, we can not yet provide
         quantitative estimates of the impacts. Thus, it has not yet been possible to
         demonstrate the significance of the issue to public officials, which will be
         necessary before we can confidently recommend policy responses.

             What we can offer is the perspective of scientists who are beginning
         preliminary assessments which we hope will eventually assist policy makers in
         the decision process.

             We are persuaded by the point of view that the primary responsibility of
         researchers is to gradually develop an understanding of the implications of sea
         level rise in one's own country and develop recommendations based on that
         research, not on the results of analysis in other countries. Because serious
         analysis has not been undertaken, we would rather simply tell the IPCC that this
         is so than speculate on the implications of response strategies. We are pleased
         that our point of view is reflected in the conference report's section on South
         America.


                                               311










              Central and South America

                   Simply put, our strategic response to sea level rise at this time is to
              understand the problem so that in a couple of years we will have useful
              information for policy makers. This will require us to develop a comprehensive
              understanding of the coast of Brazil, then estimate inundation, erosion,
              flooding, and other effects, then evaluate the costs of alternative responses,
              and only then, recommend policies.    Accordingly, the bulk of this paper is on
              the first step -- understanding the coast.


              INTRODUCTION

                   Brazil is divided into five major geographic regions, according to
              geological, climatic, and economic characteristics (Figure 1).      Four of these
              regions border the Atlantic Ocean (North, Northeast, Southeast, and South) and
              the coastline has an approximate length of 7,400 km, without considering the
              contour of bays and islands. Extending from latitude 4* north to 34* south, with
              climates ranging from tropical to subtropical, within each region the coastline
              may be further divided into different segments according to the geomorphological
              features or processes.

                   In Brazil, erosion problems have not been generally considered as caused by
              sea level rise, although a few reports (e.g., Muehe, 1989; Tomazelli and
              Villwock, 1989) have addressed this issue very recently. Frequently, the idea
              that sea level is dropping stil,l persists.     In fact, the relative sea level
              curves established for several sectors of the Southeast and South regions for
              the last 7,000 years (Delibrias and Laborel, 1971; Suguio et al ., 1985), indicate
              that during two or three occasions, sea level has been up to 5 m higher than at
              present.

                   Despite the continuous drop in relative sea level during the last 2,300
              years, evidence of coastal erosion begin to be noticed at different parts of the
              coastline. Lack of sediment supply, increase of storm intensity, local tectonic
              movements, and human interference may all contribute to this erosion.          The
              absence of long-term tidal data and also the scarcity of topographic and
              cartographic material makes it difficult to follow coastal changes for a longer
              time span into the past. Most of the studies about coastline changes have been
              limited to typically unstable areas such as tidal inlets and river mouth bars,
              and therefore cannot be considered as evidence of erosion due to a marine
              transgression.    Nevertheless, there is an increasing feeling, among some
              researchers, that a rise in sea level may also be responsible for some of the
              detected erosion.

                   In a shorter time scale, though, there might be a trend for a sea level
              rise. Pirazolli (1986) presented relative sea level curves for six locations
              in Brazil during the period 1950-1970. There was a rise at rates varying between
              5 cm/century to 35 cm/century, except for one location near the mouth of the
              Amazon River, which showed a trend for decreasing sea level. This subject is
              further discussed in the section about tidal information. Although the time span
              of observation was too short to derive a definite conclusion, it is strong enough


                                                     312










                                                                            muehe and Neves



                                                                           N



                     EQUATOR




                                                                          NORTHEAST






                           NORTH




                                   CENTRAL-WEST
                     TROPIC OF CAPRICORN                              SOUTHEAST





                                                         SOUTH


















                                      BRAZIL
                                                      ;so




















          Figure 1. Geographic regions of Brazil.

                                                   313











               Central and South America

               to justify the beginning of comprehensive studies about the subject in Brazil,
               as well as special care in obtaining tidal data.

               IMPACTS ON THE COASTLINE

                    The coast of Brazil was divided into five sectors, and for each of them the
               geomorphologic characteristics and the population distribution were presented.
               It is reasonable to assume that places with higher numbers of inhabitants per
               kilometer of coastline would be more susceptible to the impacts from a one-meter
               rise in 'sea 1 evel . Therefore, i t can be deri ved f rom maps that the major impacts
               would be limited to the neighborhood of about fifteen coastal cities where the
               den.4 .1@ty'is higher than 5,000 inhabitants per kilometer of coastline.

                   ':,As a guide for evaluating these impacts, five areas are suggested for study
               in each of the sectors owing to their geomorphologic and socioeconomic
               characteristics.    From North to South, these areas are Salinopolis (PA), near
               the mouth of the Amazon; Fortaleza (CE); Recife (PE); Rio de Janeiro.(.RJ); and
               Rio Grande (RS).

                    We briefly   summarize concerns for four coastal regions:        the Nqrth,   the
               Northeast, the Southeast, and the South.

               The North

                    The most important impact here would be the rising water levels in tidal
               rivers. Flooding of river valleys will confined to a fairly narrow area due the
               presence of high ground somewhat inland. Low-lying alluvial areas such as in
               the Marajo Island at, the river mouth, however, might be inundated. Because the
               low-lying areas in northern Brazil are now sparsely populated, major consequences
               for the economy can be avoided as long as future development in the regions
               occurs takes sea level rise into account.

               The Northeast

                    In this region, low-lying deltaic areas such as the Sao Francisco Delta will
               suffer an expansion of the mangroves into and used today for temporary housing
               and agriculture. A more serious problem will face coastal cities like Recife,
               Aracaju, and part of Maceio, where low-lying areas are flooded when heavy rains
               coincide with spring tides (Nou et al., 1983); with-50-cm rise in sea level the
               same effect would occur even during neap tides. Drainage problems and flooding
               will probably also confront the low-lying areas of the coastal plains of the
               Todos of Santos Bay in Bahia. These problems could be particularly severe in
               the heavily populated city of Recife, where urbanization has expanded throughout
               the floodplain the Capibaribe and Beberibe Rivers, exacerbating flooding and
               drainage problems (Figure 2).

               The Southeast

                    The diverse types of coasts in this region (barrier beaches, pocket beaches,
               rocky shores, coastal lagoons, bays, estuaries) will respond in different ways

                                                        314










                                                                            Muehe and Neves










                                           ar,






                                                                   '-K 4y,'














          Figure 2. Retreating   bluffs  on the coast  of Paraiba (northeast region); note
          a tree at the edge of  the bluff  (center).


          to a sea level rise.     Some areas are already eroding -- even though human
          interference is negligible -- suggesting that these areas are already exhibiting
          some of the signs of rising sea level.

              For example, during the last fifteen years, the mouth of Paraiba do Sul
          River has seen extensive beach erosion with a resulting loss of valuable property
          (Argento, 1989). On the southern part of the delta, grayish black sandstone has
          been exposed, indicating that shores are retreating. Similar processes have been
          identified by Muehe (1984, 1989) at the barrier beaches between Cape Frio and
          Guanabara Bay, -and the back side of the barrier that faces Araruama Lagoon
          appears to be eroding.

              Another area in the State of Rio de Janeiro that may suffer from a rise in
          sea level is the fluvial-marine plain along the estuary of Sao Joao River located
          about 200 km south of Paraiba do Sul River.      Currently, rice is extensively
          cultivated along the valley, using river water for irrigation.        Besides the
          potential of flooding, sea level rise could threaten the water supply as
          saltwater advances farther upstream, a process that has already been observed.

              Finally, the flat areas around Guanabara Bay appear to be vulnerable. These
          areas currently flood during heavy rains, especially along rivers and drainage
          canals.  The combined effects of a rise in sea level and siltation of those
          canals will aggravate the flooding.    Moreover, because the relative sea level
          was 5 m higher during the Holocene than today (Amador, 1974), the terrain in

                                                 315









               Central and South America

               this area is very flat and hence extensive areas are vulnerable to flooding from
               storm surges. Similar problems seem likely to afflict other coastal plains and
               river valleys in the region (Figure 3).

               The South

                    Little data have been collected on current shoreline changes. However, in
               Santa Catarina peat has emerged near the scarps of coastal barriers, indicating
               that shores are retreating.     Similarly, peat is present on the foreshore and
               along the base of the foredunes along the beaches of Rio Grande do Sul. Erosion
               along the margin of Patos Lagoon also appears to be another           indication of
               relative sea level rise. All of these trends would be exacerbated if sea level
               rise accelerated.



               OCCUPATION OF THE COASTLINE

                    A study of the impacts of sea level rise must consider not only the
               geomorphological features of the coast, but also the economic impact it would
               have on the population.     Due to the fact that no detailed assessment of the
               entire coastal zone of Brazil has ever been conducted, and also because it is
               always assumed that the population is not evenly distributed along the coast,
               the authors chose to characterize the human occupation of the coastline (measured
               in terms of inhabitants/km of coastline). This parameter is used to identify
               areas where potential impacts   would be stronger for the following reason:        an











                                                       -art -t





                                                          At-
                   fir'.





              Figure  3.  Barrier  island  of Ipanema  -Leblon, city of Rio de Janiero.     Erosive
              Processes  have been observed on Leblon Beach (top) and   waves reach the longshore
              avenue during storms.

                                                       316











                                                                              Nuehe and Neves

         area with a higher degree of occupation would most likely have more diversified
         activities (e.g., housing, water supply needs, waste disposal, harbors and
         marinas, tourism, agriculture), that would ultimately be affected by sea level
         rise.   The cost for facing the adverse impact would probably be divided among
         all local residents in the form of increased taxes, reduced revenues or
         reallocated funds, even though the population might not be at risk of flooding
         (which is the first thought of impact).

              Micro-regions, established by the Instituto Brasileiro de Geografia e
         Estatistica (IBGE), as a group of counties with homogeneous geographical
         characteristics, were chosen as the basic unit of the coastline. Then, for each
         micro-region located on the coast, only those counties that have a coastline were
         considered in this study, measuring the length of its coast and its population
         (based on 1980 census). The towns would be located at most 30 km from the coast.

              First, a comparison was made between the population living in those coastal
         counties and the population of the state (figures are presented in Table 1).
         For the country as a whole, about 20.4% of the population might be potentially
         affected by the consequences of sea level rise (not necessarily flooding). In
         the north region, both states, Amapa (AP) and Para (PA), show a high
         concentration of population near the coast, respectively 82.9% and 50.7%, even
         though their total population is not significant compared to other states. This
         is because they are both located in the Amazon region, and their capitals are
         are located on the margins of the Amazon delta.           In the northeast region,
         Pernambuco (PE) has the highest percentage (38.5%) which is explained by the dry
         weather in the interior and by its historical development since the 1600s as an
         important area of sugarcane plantations. In the southeast region, Rio de Janeiro
         (RJ) shows a percentage of 68.6%, which is a high figure. The reason is because
         the capital, the City of Rio de Janeiro, and its metropolitan region are located
         around two bays and represent the second largest urban center in the country.
         Finally, in the south region, Rio Grande do Sul (RS) is the state with the
         highest percentage of population (28.7%) in the coastal zone, mostly concentrated
         around Patos Lagoon, which has an area of 10,000 km' and whose coastline will be
         affected by sea level rise.

              A second study was conducted in order to quantify the population density per
         unit length of coastline. Four classes were identified: those where the density
         was less than 1,000 hab/km, which characterizes remote areas; those where the
         density was between 1,000 and 5,000 hab/km, characteristic of most urbanized
         areas, where the economical activities should be more important; those with a
         density between 5,000 and 10,000 hab/km, typical of medium size cities, usually
         around state capitals; and, finally, above 10,000 hab/km, typical of large
         cities.

              It was observed that 47.4% of the coastline has very low occupation (a
         weighted average value of 522 hab/km). These localities, include preservation
         areas, small towns without appropriate surveying, or areas where data about
         coastline evolution would not be available at all. Consequently, it is difficult
         to make an assessment of impacts of sea level variations. On the other hand,
         it also suggests that a planned occupation -- which should take into account

                                                  317










              Central and South America


                       Table 1. Population Living in the Coastal Zone (1980 Census)

                                                     Population                      Percentage
              Region         State         In the state       On the Coast              M


                I              AP              175,257           145,313                82.9

                               PA          3,403,391           1,726,131                50.7


                2              MA          3,996,404           1,024,148                25.6

                               PI          2,139,021             127,798                 6.0

                               CE          5,288,253           1,869,026                35.3

                               RN          1,898,172             634,906                33.4

                               PB          2,770,176             400,831                14.5

                               PE          6,141,993           2,367,686                38.5

                               AL          1,982,591             644,720                32.5

                               SE          1,140,12  1           435,985                38.2

                               BA          9,454,346           2,622,432                27.7


                3              ES          2,023,340             845,546                41.8

                               RJ          11,291,520          7,748,200                68.6

                               SP          25,040,712            826,490                 3.3


                4              PR          7,629,392             101,804                 1.3

                               SC          3,627,933             877,168                24.2

                               RS          7,773,837           2,234,681                28.7

                            Brazil        119,001,427          24,232,034               20.4

              NOTE: Region -- 1       North; 2 = Northeast;   3 = Southeast; 4     South.




                                                      318











                                                                         Muehe and Neves

        data about sea level trends in neighboring areas -- would be the "best
        response"to avoid future problems.

             In other areas, which amount to fifteen cities and 12.7% of the coastline,
        the population has already been established.    Usual coastal engineering works
        for shore protection would be feasible there and detailed studies (for past
        evolution and future observations) are economically justifiable.

        TIDAL INFORMATION

             Tide data in Brazil has usually been obtained by the port authorities and
        by the Navy for navigation purposes.      For various reasons -- like cost of
        maintenance and repair of equipment -- the time series has many gaps; this
        prevents a study of long-term variations.

             As a rough guide of the tidal variation along the coast of Brazil, Table 2
        presents figures obtained from the 1989 Tide Table published by the Diretoria
        de Hidrografia e Navegacao (DHN) for different ports along the coast.       It is
        interesting to observe the decrease in tidal range, from 5.0 m near the Equator
        to 0.5 in Rio Grande, at the southern part of the country.

             Studies conducted by Pirazolli (1986), including six locations in Brazil
        during the period 1950 through 1970, indicated a trend for sea level rise in four
        stations (Recife (PE), 27 cm/century; Salvador (BA), 16 cm/century; Canavieiras
        (BA), 31 cm/century; and Imbituba (SQ, 5.5 cm/century; in Fortaleza (CE), the
        sea level has oscillated by an amount of 6.6 cm in fifteen years, showing a trend
        for rise at the end of the period of observation; in Belem (PA), there was an
        oscillation of 2.2 cm in twenty years, with a trend for decreasing in the last
        seven years of observation.       This data justified    the need for further
        investigation. Currently, groups of researchers at the Universidade Federal do
        Rio de Janeiro (UFRJ) and at the Instituto Oceanografico da Universidade de Sao
        Paulo (IOUSP) are studying long-term sea level variations at various points along
        the coast.  The work, which should be completed by the    end of 1990, includes:
        retrieval of tide data from graphs to digital format; correction for changes in
        datum; verification of errors and gaps; and determination of daily, monthly, and
        yearly mean sea level curves.

             Brazil already participates in the GLOSS program of the Intergovernmental
        Oceanographic Commission (UNESCO), and the DHN of the Brazilian Navy is
        responsible for the installation of ten permanent tide gauges in the country,
        including three stations at oceanic islands. The IOUSP and the Brazilian Port
        Authority holding company (PORTOBRAS) also participate in this effort being
        responsible for two stations. Combining the data already available for the past
        twenty years with the data to be obtained during the next twenty years will
        enable us to have a clear picture of relative sea level changes at the beginning
        of next century.





                                               319










                  Central and South America


                                       Table 2. Tidal Range Along the Coast of Brazil


                                                                                            Spri',ng  tide
                    Region'       State           Location                Type              HW'  ' LW'; AH"

                        1            AP           Barra Norte              E              4.16    0.37    3.79
                                     PA           Salinopolis              M              5@08    0.36-   4.72

                        2a           MA           Itaqui                   B              6.28   -0.44    51* 84
                                     PI           Luis Correia             M              3.27    0.20    3.07
                                     CE           Mucuripe                 01             .2* -93 0*  17  2.76
                                     RN           Areia Branca             0              3.-50   0.24    3.26

                        2b           RN           Natal                    E              2.12.  @0.11    2.01
                                     PB           Cabedelo                 E              2.36    0-.08   2,.28
                                     PE           Recife                   M              2.33    0.10    2.23
                                     AL           Maceio                   E              2.34   -0.01    2.35
                                     SE           Aracaju                  E              2.64   .0.06    1.98
                                     BA           Salvador                 B            1 2.52   10.18    :2.34
                                     BA           Ilheus                   0              2.20    0.19    2.01

                       3             ES           Barra do    Riacho       0              1.60    0.08    1.52
                                     ES           Tubarao                  0              .1.50   0.04    1.46
                                     RJ           Cabo Frio                .0             1,26-   0.09    1.17
                                     RJI          Rio de Janeiro           B              1.29    0.12@   1.17
                                                                                          .1.19'.0.03     1.16
                                     SP           Sao Sebastiao            0                     i
                                     SP           Santos                   E              1.50-  '0.04    1.;46

                       4             PR           Paranagua                M              1.64    0.07    1.57
                                     SC           Itajai                   E              1.13    0.12    1.01
                                     SC           Imbituba                 0              0.72    0.01    0.71
                                     RS           Rio Grande               M              0.431   0..05   0.38

                  a Region: I = north;         2a = northeast, from          Maranhao     to,.Cape Calcanhar; 2b
                    northeast, from Cape Calcanhar to Bahia; 3                  southeast; 4 = south
                  b Type of location of the tidal stations: 0                   open coast; B =,inside bay; E
                    in estuaries; M = at the mouth of the estuary or bay ",
                  c HW = mean values of        high water spring tide (elevation in meters relative to
                  d local datum).
                    LW = mean values of         low water spring tide (elevation in meters relative to
                    local datum).
                   AH = HW - LW.
                  Source: Values from 1989 Tide Table.







                                                                   320










                                                                          Muehe and Neves

        INSTITUTIONS INVOLVED IN ENVIRONMENTAL NANAGENENT

             The Constitution of 1988 and the state Constitutions that followed brought
        the environmental issues into a legal framework by declaring in one of its
        chapters that "all have the right to an environment that is in ecological
        balance."   It also includes the coastal zone among the areas classified as
        "national heritage."

             Brazil's National Coastal Zone Management Plan (PNGQ was established in May
        1988. The Comissao Interministerial para os Recursos do Mar -- the government
        agency for sea resources -- is responsible, through its Secretary for Coastal
        Zone Management, for establishing general goals and common policies, and for
        giving technical and financial support to state and municipal agencies. However,
        each State is responsible for developing its own Coastal Management Plan. Each
        plan is supposed to include "macro-zoning" of the coast, the monitoring program,
        and a geographical information system. Because the program is new, macro-zoning
        is progressing in only six states, including Rio de Janeiro.

             The various consequences of sea level rise -- erosion, flooding, and
        saltwater intrusion -- are intrinsic  to any management plan. However, officials
        are not yet convinced that there is   a problem. Many researchers still believe
        that sea level is falling around the  coast of Brazil; and information on current
        sea level and even shoreline trends   is unavailable for most of the coast.

             Regarding the climate changes issue, the Brazilian government took an
        important step in October 1989 by     enacting a law that creates the Comissao
        Interministerial sobre Alteracoes Climaticas -- an interministerial committee
        for climate changes, which includes the Secretaries of eight federal ministries,
        the Secretary of the Comissao Interministerial para os Recursos do Mar, and the
        directors of seven institutions related to research on meteorology, space
        science, environment, and agro-sciences.

             Finally, studies are currently being developed in Congress in order to
        establish a national management plan for water resources. Dams for irrigation,
        water supply, and hydroelectric power plants can alter the balance of estuaries
        downstream; The significance of these impacts may be much greater than currently
        anticipated if sea level rise accelerates; and transition to a drier climate
        could further amplify the interactions between water resources and coastal
        management.   Thus, these two programs need to work together to ensure that
        solutions to one type of problem (e.g., increased water supply needs to
        counteract increasing droughts) do not create other problems downstream (e.g.,
        increased saltwater intrusion and loss of sediment in deltas).

             The results of the new programs will not be known for many years. Whether
        they are going to work depends mostly on the amount of funds and effort that will
        be invested in environmental education.






                                               321











               Central and South America

               MANAGEMENT PROGRAMS

                   The National Coastal Zone Management Plan was established in Brazil
               according to the Federal Law No. 7661 on May 16, 1988.     It is made up of the
               National Policy for the Environment and the National Policy for Sea Resources.
               The Comissao Interministerial para os Recursos do Mar -- the government agency
               for sea resources -- is responsible, through its Secretary for Coastal Zone
               Management, for establishing general goals and common policies, and for giving
               technical and financial support to state and municipal agencies. However, each
               state is responsible for developing its own Coastal Management Plan. Each plan
               should include the macro-zoning of the coast (which is summarized in twelve
               thematic maps), the monitoring program, and the Geographical System of
               Information. A detailed explanation of PNGC can be found in Frischeisen et al.
               (1989) and Azevedo et al. (1989).

                   The PNGC is still in its infancy: the macro-zoning program is in progress
               in only six states (Rio Grande do Sul and Santa Catarina in the south region,
               Sao Paulo and Rio de Janeiro in the southeast region, and Bahia and Rio Grande
               do Norte in the northeast region) and it is expected to be completed by 1992.
               The concerns about a possible sea level rise are intrinsic to any management
               plan. However, in practice, it becomes very difficult to consider relative sea
               level variations either because tidal data are not available, or because there
               is no reference line that can be used to control erosion along unpopulated
               stretches of the coast.

                   Regarding climate changes, the Brazilian government took an important step
               by passing Federal Law No. 98352 on October 31, 1989.      This law created the
               Comissao Interministerial sobre Alteracoes Climaticas -- an interministerial
               committee for climate changes. The committee includes the Secretaries of eight
               federal ministries, the Secretary of the Comissao Interministerial para os
               Recursos do Mar, and the directors of seven institutions related to research on
               meteorology, space science, environment, and agro-sciences.

                   Finally, studies are currently being developed in Congress in order to
               establish a national management plan for water resources.         The Brazilian
               Association for Water Resources (ABRH), an association of engineers and other
               professionals who deal with hydraulic engineering and water resources,
               contributes to this plan by forwarding several proposals to the Congress
               committee.   Multiple uses of water resources (irrigation, water supply,
               hydroelectric power plants, construction of dams) cause changes in river
               discharge, which alter the environment of estuaries downstream. The significance
               of these impacts may be much greater than currently anticipated if the climate
               becomes drier and sea level rise accelerates. Thus, it is desirable that the
               management plans for water resources and for the coastal zone work together to
               ensure that solutions to one type of problem (e.g., increased needs for water
               supply) does not create other problems downstream (e.g., increased saltwater
               intrusion and loss of sediment in deltas).

                   Perhaps the most difficult part is to establish stations and routines for
               collecting data, which is usually a very expensive task. Taking into account

                                                     322











                                                                          Nuehe and Neves

         all regional differences in socioeconomic needs and priorities, as well as those
         differences in impacts due to global weather and oceanographic changes, the
         establishment of those national committees gives a promising perspective.

              The results of all these plans will be felt in the future, though. Whether
         they are going to work depends mostly on the amount of funds and effort that will
         be invested in environmental education.


         ENVIRONMENTAL LEGISLATION FOR THE COASTAL ZONE

              The most important step in environmental legislation, with consequences yet
         to be perceived, was given by the Brazilian Constitution of 1988 and the State
         Constitutions which followed.    Environmental issues were brought into a legal
         framework by the declaration in one of its chapters that "all have the right to
         an environment which is in ecological balance." It also includes the coastal
         zone among the areas classified as "national heritage."

              Since 1934, the "Code of Water Resources" has been the basic law which
         regulates the uses of water resources, the occupation of the margins of rivers
         and lakes, and the occupation of the coastal area.   It establishes that a strip
         of land 33 m wide, inland from a specific high-water line, belongs to the Union.
         Together with a resolution of the Brazilian Navy, public access to the shore is
         granted.

              The National Policy for the Environment (1981) established the creation of
         a National Committee for the Environment (CONAMA) including representatives from
         federal ministries and civil organizations.     CONAMA has since then approved
         several resolutions for protection of sensitive areas and for establishment of
         ecological stations. The following areas are included among those of permanent
         protection (Resolution 004, 1985): barrier islands, spits, and barrier beaches
         up to 300 m inland from the highest water line; mangroves; vegetation for fixing
         dunes; wetlands and other areas used by migrating birds; and land up to 100 m
         around lakes, lagoons, and reservoirs.    As a matter of fact, since 1965, the
         "Forest Code" had considered mangroves    and vegetation on dunes as being of
         permanent protection

              The legal framework which grants a balanced use of the environment is
         essentially established.    In addition to the federal laws listed above, each
         state has its own regulations and policies.   In a scenario of sea level rise and
         climate changes, some of these legislations may need to be reviewed in face of
         scientific studies. However, the most urgent problem for the country seems to
         be how to enforce these laws, in such a vast area, with very limited resources.
         Furthermore, without the social and educational development of a large percentage
         of the population, it is extremely hard to achieve the goal of living in an
         ecologically balanced environment.





                                                323











              Central and South America

              CONCLUSION

                   We have only begun to assess the implications of sea level rise and the
              greenhouse effect. Upon further investigation, we may find that we have been
              overlooking impacts that are more important than those described here; and some
              of the impacts that now seem serious may prove to be manageable. Any conclusions
              thus must be viewed as tentative and illustrative hypotheses necessary to guide
              future research.

                   In our view, the expected global rise in sea level implies that municipal,
              state, and federal authorities should take a preventive approach when selecting
              sites for urban expansion and location of industries. Due to the high cost of
              protecting developed areas from such a rise, this "preventive approach" includes
              the following steps:

                   1.  Enforce coastal management programs, as the one currently in progress,
                       and establish urbanization plans according to those programs;

                   2.  Install long-term tidal gauges in order to furnish, twenty years from
                       now, reliable data for inferring sea level trends;

                   3.  Establish a methodology for observing (and quantifying) the evolution
                       of shoreline, mangrove areas, and other coastal features;

                   4.  Maintain a systematic data bank for oceanographic and meteorologic
                       information according to international standards;

                   5.  Incorporate the results of scientific assessments into coastal
                       development plans, for example, by requiring construction to be set back
                       from the shore;

                   6.  Adopt flexible criteria for designing harbors and coastal structures,
                       which take into account all the information available for the site and,
                       at least, a "lower expectation" of sea level rise; and
                   7.  Formulate educational programs about environmental (particularly
                       coastal) protection and global climatic effects, addressed to different
                       levels of the population.

                   The costs involved in these cautious measures could bring significant
              benefits in the future and could avoid greater socioeconomic impacts.


              BIBLIOGRAPHY

              Amador, E.S. 1974. Praias fosseis do reconcavo da baia de Guanabara. An. Acad.
              Brasil. Cienc. 46(2): 253-262.




                                                    324











                                                                                Nuehe and Neves

         Angulo, R.J. 1989. Variacoes na configuracao da linha de costa no Parana nas
         ultimas quatro decadas. II Cong. da Assoc. Bras. de Estudos do Quaternario. Rio
         de Janeiro, July 10-16, 1989. (in press).

         Argento, M.      1989.     The Paraiba do Sul retrogradation and the Atafona
         environmental impact.      In: Neves, C. and Magoon. O.T. (ed.) Coastline of Brazil.
         American Society of Civil Engineers, New York. p. 267-277.

         Azevedo, L.H., D.M.W. See, and D.R. Tenenbaum.         1989.   Coastal zone planning.
         In: Neves, C. and Magoon, O.T. (ed.) Coastline of Brazil. American Society of
         Civil Engineers, New York. p. 70-83.

         Bandeira Jr., A.N.; S. Petri, and K. Suguio. 1975. Projecto Rio Doce: Petroleo
         Brasileiro S.A., Internal Report, 203 p.


         Cruz, 0., P.da N. Coutinho, G.M. Duarte, A.M.B. Gomes, and D. Muehe.               1985.
         Brazil.   In: Bird E.C.F. and M.L. Schwartz (ed.), The World's Coastline.            Van
         Nostrand Reinhold Co., New York. p. 85-91.

         Delibrias, C., and J. Laborel. 1971. R ecent variations of the sea level along
         the Brazilian coast. Quaternaria, XIV: 45-49.

         Dias, G.T.M.    1981.   0 complexo deltaico do Rio Paraiba do Sul.         IV simposio
         Quaternario no Brasil. Publ. Especial. 2:35-74. Rio de Janeiro.

         Dias, G.T.M., and M.A. Gorini. 1979. Morfologia e dinamica da evolucao do delta
         atual do rio Paraiba do Sul. Anais da V Semana de Geologia, UFRJ. Rio de Janeiro.

         Dias, G.T.M., and C.G. Silva. 1984. G eologia de depositos arenosos costeiros
         emersos -- exemplos ao longo do litoral fluminense.            In: Lacerda, L.D. de,
         Araujo, D.S.D. de, Cerqueira, R. and Turcq, B. (ed.)               Restingas: Origem,
         Estrutura, Processos. CEUFF, Niteroi. p. 47-60.

         Dominguez, J.M.L. 1989. Ontogeny of a strandplain: Evolving concepts on the
         evolution of the Doce river beach-ridge plain (East coast of Brazil).
         International Symposium on Global Changes in South America during the Quaternary:
         Past -- Present -- Future. Sao Paulo, May 8-12. Special Publication 1:235-240.

         Dominguez, J.M.L., L. Maratin, A.C.S.P. Bittencourt, Y. de A. Ferreira, and J.-
         M. Flexor. 1982. Sobre a validade da utilizacao do termo delta para designar
         planicies costeiras associadas as desembocaduras dos grandes rio brasileiros.
         32 Congr. Bras. Geol., 2 (Breves Comunicacoes): 92, Salvador.

         Franzinelli, E. 1982. Contribuicao a geologia da costa do Estado do Para (entre
         a baia de Curaca e Maiau). In: K. Suguio, M.R.M. de Meis, and M.G. Tessler (ed.)
         Atas IV Simposio do Quaternario no Brasil. Rio de Janeiro, July, 27-31. p. 305-
         322.




                                                   325










               Centra7 and South America

               Frischeisen, E.R., M.S.F. Argento, R. Herz, and R.P. Carneiro.              1989.    The
               Coastal Management Program in Brazil. In: Neves, C. and Magoon,.            O.T. (ed.)
               Coastline of Brazil. American Society of Civil Engineers, New York. p. 1-9.
               Marques, R.C.C. 1987. Geomorfologia e evolucao da regiao costeira          do complexo
               estuarino lagunar Mundau-Manguaba. M.Sc. thesis, Departamento de Geografia,
               Universidade Federal do Rio de Janeiro. Rio de Janeiro. 152 p.

               Martin. L.., and K. Suguio.      1989.   Excursion route along the Brazilian coast
               between Santo (State of Sao Paulo) and Campos (North of State of Rio de Janeiro).
               International Symposium on Global Changes in South America during the Quaternary.
               Sao Paulo, May 8-12, 1989. 136 p.

               Martins, L.R., and J.A. Villwock.         1987.   Eastern South America Quaternary
               coastal and marine geology: A synthesis. In: Quaternary coastal geology of West
               Africa and South America. INQUA-ASEQUA Symposium, Dakar,' April 1986. p. 28-96.

               Muehe, D.    1984.    Evidencias de recuo dos cordoes litoraneos em direcao ao
               continente no litoral do Rio de Janeiro. In: Lacerda, L.D. de, Araugo, D.S.D.
               de, Cerqueira, R. and Turcq, B. (ed.) Restingas: Origem, Estrutura, Processos.
               CEUFF, Niteroi. p. 75-80.

               Muehe, D., and C.H.T. Correa. 1989.       The coastline between Rio de Janeiro and
               Cabo Frio. In: Neves, C. and Magoon,      O.T. (ed.) Coastline of Brazil. American
               Society of Civil Engineers, New York.     p. 110-123.

               Nou, E.A.V., L.M. de M. Bezerra, and M. Dantas.          1983.    Geomorfologia.     In:
               Projeto Radam Brasil. Levantamento de     Recursos Naturais V. 30, Folhas SC 24/25,
               Aracaju/Recife. Ministerio das Minas      e Energia. Rio de Janeiro.

               Nunes, T. de AX, V.L. de S. Ramos, and A.M.S. Dillinger. 1981. Geomorfologia.
               In: Projeto Radam Brasil . Levantamento de Recursos Naturai s V. 24, Fol ha SD 24,
               Salvador. Ministerio das Minas e Energia. Rio de Janeiro.

               Pirazolli, P.A.     1986.    Secular trends of relative sea level (RSL) changes
               indicated by tide-gauge records. Journal of Coastal Research, SI, 1:1-26.

               Prates, M., L.C.S. Gatto, and M.I.P. Costa. 1981. Geomorfologia. In: Projeto
               Radam Brasil.     Levantamento de Recursos Naturais V. 23, Folhas SB 24/25,
               Jaguaribe/Natal. Ministerio das Minas e Energia. Rio de Janeiro.

               Prost, M.T., M. Lintier, and B. Barthes.        1988.    Evolution cotiere en Guyane
               Francaise: La Zone de Sinnamary.           35 Congr. Bras. Geol . and 7 Congr.
               Latinoamericano Geol. Abstracts. Belem,        Brazil, Nov 6-13, 1988, p. 407.

               Silveira, J.D. da 1964. Morfologia do litoral. In: Azevedo, A. de. ed. Brasil
               a terra e o homem. Sao Paulo, Cia. Editora Nacional. p. 253-305.




                                                         326











                                                                                  Muehe and Neves

           Suguio, K. and L. Martin. 1976. Brazilian coastline Quaternary formations -
           The State of Sao Paulo and Bahia littoral zone evolUtive schemes.            An. Acad.
           Bras. Cienc., 48 (Suplemento): 325-334.

           Suguio, K., and L. Martin. 1981. Progress in research on Quaternary sea level
           changes and coastal 'evolution in Brazil.        Proc. Symp. on Holocene Sea Level
           Fluctuations, Magnitude and Causes, 1981, Dept. Geology, USC: 166-181.

           Suguio, K., L. Martin, A.C.S.P. Bittencourt, J.M.L. Dominques, J.-M. Flexor, and
           A.E.G.de Azevedo.      1985.    Flutuacoes do nivel relativo do mar durante o
           Quaternario Superior ao longo do litoral brasileiro e suas implicacoes na
           sedimentaca costeira. Rev. Bras. Geoc., 15 (4): 273-286.

           Tomazelli, L.J., and A. Villwock.       1989.   Brasil: evidencias de uma provavel
           tendencia contemporahea de elevacao do nivel relativo do mar. II Cong. da Assoc.
           Bras. de Estudos do Quaternario. Rio de Janeiro, July 10-16, 1989 (in press).
































                                                     327











               Centra7 and South America

                             APPENDIX: GEONORPHOLOGICAL DESCRIPTION OF THE COAST


                    General classifications of the main features of the Brazilian coastline have
               been presented by Silveira (1964) and by Cruz et al. (1984).            Martins and
               Villwock (1987) presented a modified version based on the other two
               classifications. In the present paper, a similar pattern is followed with a few
               modifications.

                    The Barreiras group, which is mentioned in this classification          scheme,
               represents tertiary sedimentary accumulations of varied composition and      extends
               from the North up to the Southeast Region.     Its flat-topped, table-like   surface
               was deeply incised by the drainage system during the Pleistocene             climate
               fluctuations. At the coast these deposits occur in the form of active        or dead
               bluffs, several tens of meters high, carved by the action of waves. Lateritic
               concretions, found inside the deposits in the zone of the groundwater table
               fluctuation, are frequently preserved at the inner shelf, indicating the
               amplitude of coastal recession.

               The North Region

                    The North Region extends from Cape Orange in Amapa (AP), at the border
               between Brazil and French Guyana, up to the south of the State of Para (PA)
               (Figure A-1). The 1,080-km-long coastline is strongly influenced by the sediment
               discharge of the Amazon, which is responsible for the enormous enlargement of
               the continental shelf. In front of and northward from the river mouth, the 10-
               and 50-m isobaths occur, respectively, at distances of about 100 and 150 km from
               the coast. The influence of the Amazon sediments could be followed, during the
               recent AMASED expedition, up to about 200 km offshore, where a sharp boundary
               between turbid and clear ocean water marked the distal influence of the river.
               Southward from the river mouth, the distances of the 10- and 50-m isobaths reduce
               to respectively 10 to 80 km.     Both the north and south segments, the coast is
               characterized by a fringe of muddy sediments, deposited in front of a Barreiras-
               like hinterland and covered by mangroves.         The south segment presents an
               irregular coastline, while the northern segment presents a smoother shoreline.
               These differences are obviously due to the large amounts of sediments from the
               Amazon River transported to the north.

                    Due to a tidal range of more than 3 m (reaching 10 m at some locations),
               erosive processes are strong.     The low gradients of the rivers allow a wide
               penetration of tides.      Problems have not been reported so far, but large
               destruction of mangroves at the ocean front occurs at the north sector (Dias,
               personal communication).    Naturally, without long-term observation it is not
               possible to know if this is a general trend or only a cyclic phenomenon, as
               related by Prost et al. (1988) for the mangrove coast of French Guyana. For the
               south sector Franzinelli (1982) described the presence of active bluffs at
               Atalaia beach in Salinopolis, where the sediments of the Barreiras group lie on
               top of the calcareous sediments of the Pirabas Formation (Figure A-2).           Dead
               bluffs, 7 m high, are also found at distances of about 100 m from the shoreline,
               in places where the Barreiras group has been eroded by a higher sea level.

                                                       328











                                                                                                                                                Muehe and Neves
















                      NORTH REGION

                                                                                                                                                           AP





                                                                               I CIA
                                                     OIAPOGIN

                                                                                                                                                       BRAZIL














                                                                                MARAjO6 is


                                            -AZ AS





                                                                                                                                                     MUD DEPOSITS. BARREIRAS GROUP


                                                                                   TOCANTINS RWEF1            "UPI RIVER                             BARREIRAS GROUPRLAS.MANGROVES







                                                                                                                                                                SCALE
                                                                                                                                                            5?5r@@O Mi,,
                                                                                                                                                           AP








                                                                                                                                                          ZfL
                                                                                                                                                       @RA






















                     Figure A-1.                Classification of main physiographic features of the Brazilian
                     coastline: North Region.

                                                                                               329










                     Central and South America



                                    ALGO   L   I T                                         0 J7



                                                                                                                      ATALAIA
                                                                                                                             IONT
                                                                                                    SA M6POUS

                                                          Ma racand

                                                             Boy




                                0'40'
                                                                                ........  ....






                                                                                     ........                             .....



                                                                                                                          X.



                                                                                                               ...........  ............
                                                                           MiAACANi
                                             ......... ......                                             ......
                                           ..........                                              L02-1
                                                                                                             -X
                                                                                                              .............
                                                                               7..:
                                       MAGA-1  ES BARATA



                                                                                               . . ........
                                                                                                     ...........


                                                                                                           .... ......



                                                                                                        ............
                                                                              X






                                       LEGEND


                                               Mangrove deposits                             $CA L


                                               Tidal flat deposits.
                                                     Sand and Silty send
                                               BarreifG5 Group
                                                                               GEOLOGIC MAP OF PARA STATE COAST
                                               Li.thologic Contact             NEAR MARACANZ AND SALINdPOLIS
                                               Clif f 5                        Afodifled from F.-onzinelli, 1982

                                               Beach   ridges


                                               Cities




                     Figure A-2. Geologic map of part of the ria coast of Para, between Maracana and
                     Salinopolis. (Frazinelli, 1982; Martins and Villwock, 1987).

                                                                               330











                                                                            Muehe and Neves

               For the whole region, a sea level rise will significantly increase the
          penetration of the tidal wave into the rivers. Flooding along the river valleys
          will be laterally confined by the higher areas of the Tertiary and Pleistocene
          sedimentary deposits.    Depending on the sediment budget, low-lying alluvial
          areas such as in the Marajo Island at the river mouth, will be inundated.

          The Northeast Region

               The Northeast Region consists of nine states: Maranhao (MA), Piaui (PI),
          Ceara (CE), Rio Grande do Norte (RN), Paraiba (PB), Pernambuco (PE), Alagoas
          (AL), Sergipe (SE), and Bahia (BA) (Figures A-3 and A-4).

               With a length of about 2,480 km, the coast can be divided into two distinct
          sections. The first has a coastline 1,540 km long, roughly aligned in the east-
          west direction; the climate is dry and consequently extensive dune fields extend
          from the State of Maranhao up to Cape Calcanhar. The other section, southward
          from Cape Calcanhar up to the State of Bahia in the vicinity of Abrolhos plateau,
          has a coastline 1,940 km long, is aligned in the general north-south direction,
          and is subject to a humid climate.

               The shelf width is narrow when compared to that of the North Region. The
          width of the inner shelf, roughly based on the 50-m isobath, decreases from up
          to 70 km, in the northern sector of the region, to only 25 km in the south, with
          a new enlargement to more than 100 km at the Abrolhos plateau in the southern
          extremity of the State of Bahia.

               Deposits of the Barreiras group are typical for the whole region, as are the
          alignments of beach rocks ("recifes") in front of the shoreline (Silveira, 1964).
          The recifes frequently provide an important protection against the action of
          waves.

               Coastal plains   are generally narrow, depending on the distance of the
          retreat of the front  scarp of the Barreiras group, but increase their extension
          by penetration along  the lower courses of the river valleys (Nunes et al., 1981;
          Prates et al., 1981;  Nou et al., 1983). In some places bluffs are still under
          the action of waves. In others, the coastal plain enlarges in front of major
          rivers and at the deltas of the Parnaiba River (at the border between Maranhao
          and Piaui), Sao Francisco River, at the border of the States of Alagoas and
          Sergipe, and in front of the Pardo and Jequitinhonha Rivers in the southern
          State of Bahia.

               A large number of estuaries are found inside or in the proximity of the
          Todos os Santos Bay in Bahia.

               As in the North Region, very few studies are available about recent coastal
          evolution. Marques (1987), in her study about the barrier beach in front of the
          Mundau-Manguaba estuarine lagoonal complex in Alagoas, showed a continuous
          lateral progradation of the barrier northeast from the tidal inlet during the



                                                 331









                            Central and South America













                            NORTHEAST REGION: FROM MARANHAO TO CAPE CALCANHAR                                                                                             A





                                                                                                                                                                   BRAZIL





                                                                          SAO MARCOS DAY


                                                OUAUPI ROWR


                                                                                                     -A

                                                                                          M"M I  RIVER




                  L


                                                                                                                                    xWER.                           CAPE &1.CVWk






                                                                                                                                                                   BARI&INAS GROUNW,M)IM04I)YES


                                                                                                                                                          17-77'.1 D0NES.BARREIIFtAt,6W0Lr








                                                                                                                                                                               SCALE








                         Figure A-3.                  Classification of main physiographic fea                                               tures of the Brazilian
                         coastline: Northeast Region from Maranhao to Cape Calcanhar.

                                                                                                        332











                                                                                                                       Muehe and Neves





                             NORTHEAST REGION: FROM CAPE CALCANHM TO SAWA




                                                                            CAM                                            P9
                                                                                                          Q

                                                                                                         BRAZIL

































                                                     T   0$ zoom "Y







                                                   ta




                              JIMW
                                M"M
                                                                                                        BARREIRAS GROUP, DUMMAEACH ROCKS


                                                                                                        SARREIRASGROUPAELTAWACH      pq












                                                                                                                  SCALE
                                                                                                                              Km



                 Figure A-4.           Classification of main physiographic features of the Brazilian
                coastline: Northeast Region from Cape Calcanhar to Bahia.

                                                                             333











              Central and South America

              period 1956 to 1984 and a net erosion, during the same period, at the southwest
              segment. But these changes may reflect only a local instability of a naturally
              unstable coastal segment and not a consequence of a sea-level rise (Figure
              A-5).

                   Flooding in most of the coastal area due to sea level rise will be limited
              in extension by the scarps of the Barreiras group.         Low-lying areas of the
              deltas, like the Sao Francisco Delta, may show changes in mangroves (both in area
              and in species of trees) and a possible limitation         of the areas used for
              temporary cultures. A more serious problem will arise in coastal cities like
              Recife, Aracaju, and Maceio, where the expansion of urbanization into low-lying
              areas actually provokes inundations when heavy rains coincide with spring tides
              (Nou et al., 1983); with a 50-100 centimeter rise in sea level the same effect
              would occur even during neap tides.       Drainage problems and inundations will
              probably also affect the low-lying areas of the coastal plains in the confluence
              of the Todos os Santos Bay in Bahia. These problems will become critical in the
              heavily populated city of Recife, where urbanization has expanded over the valley
              floor of the rivers Capibaribe and Beberibe, and where drainage problems and
              floodings very often occur.

                   Just north of the mouth of these rivers, a long and severe history of
              erosion has been recorded in the nearby historical town of Olinda. The causes
              of erosion are not completely clear yet.        The area suffered subsidence in
              geological time.     However, several engineering works. -- groins, detached
              breakwaters, dredging -- that have been built might have accelerated the eroding
              process.   A rise in sea level will strongly affect this area, and further
              problems will arise due to an intensification of erosion.

              The Southeast Region

                   The 1,530-km-long coastline of the Southeast Region consists of the States
              of Espirito Santo (ES), Rio de Janeiro (RJ), and Sao Paulo (SP) (Figure A-6).
              Like the other regions examined, the table-like Barreiras group is still present,
              governing the width of the coastal plains up to the northern part of the State
              of Rio de Janeiro. An increase in the width of the coastal plains is due to the
              Rio Doce Delta in Espirito Santo State and the 'Paraiba do Sul Delta in the
              northern part of Rio de Janeiro State (Figure A-7). The adequacy of the term
              "delta" for both of these depositional features has been questioned by Dominguez
              et al. (1982), based on the argument that the progradation in front of the river
              mouth is a result of longshore drift of sediments derived from the inner shelf
              and not of fluvial sediment accumulation, as assumed by Bandeira et al. (1975)
              for the Doce River Delta and by Dias et al. (1979) and Dias (1981) for the
              Paraiba Delta. More recently, Dominguez (1989) changed his interpretation about
              the Doce river delta or strandplain, attributing a more significant role to the
              river as a sediment supplier than in his earlier model.

                   Southward from the Paraiba Delta, at Cape Frio, the coastline changes from
              northeast-southwest to an east-west direction. This stretch ends at Marambaia
              Island and is formed by barrier beaches, the only interruption being the rocky
              coast near the mouth of Guanabara Bay. The barriers may occur as either single

                                                      334











                                                                                                                         Nuehe and Neves












                                                                  V








                                                                                                                                1956








                                                                                                                      --7


                                                                                                                               Zz_
                                                                                                                                 1965














                                                                                                                                 1977

                                                    SANTA RITA 13. IL                                        PERREXIL IS.

                                                                          GIBOIA
                                                                  =59

                                                                                                                  SPIT



                                                                                                                               11984-85
                                            0                    2 Km
                               >4,q
                                  'O.q













                 Figure A-5. Shoreline modifications of the barrier beach in front of the Mundau-
                 Manguaba lagoonal-estuarine complex in Maceio, Alagoas (Marques, 1987).

                                                                               335










                                  Central and South America


















                            SOUTHEAST REGION








                                                                                                                                                                                               DRAZIL



                                                                                                                                                                                                             sp












                                                                                                             PAPAIIA 00
                                                                                                             PJL


                                                                                                                                   /*                                                          DARHE IkA!; bH01 11'. 81 ACH RJVL",
                                                                                                                        19 1 10                                                                DELTA
                                                                                         ILMA OPANDE                                                                                           ItAkkil It WAcWf5,W4cW fXCIPS.
                                                                                            94Y


                                                                                                                                                                                               NOCK f 5(^FkPS.j5t.ANpSJKACN WpM
                                                                                                                                                                                               MANGROVES
                                                   CANNIZA/111UNq         I/                                                                                                                   BEAC.Ii k1r)GI.';,8*V5,.MAWAVVE5
                                                                                                                                                                                    End






                                                                                                                                                                                                              SCALE









                               Figure A-6.                        Classificat                 ion of main physiographic features of the Brazilian
                               coastline:                    Southeast Region.

                                                                                                                             336










                                                                                                                                                    Nuehe and Neves

                                           41640'                              41*30'                4r2d                       41*10'                          41*00
                                                       (1) EMO                    @(3)
                                                                                                             40
                                                                                                     If
                                                       (4) r;___7 (5)
                                                                                                         (8) 1-*111

                                                                     +         + +
                                           t
                                         + J                                                                                                                        11030'
                                       4- 4-
                                       +               ++
                                       + +' + + + + +                4 4-               +
                                         +             ++ +   +  +   +. +
                                       +++
                                                              +                +                                            NP k
                                       -t    + 4       4      +      + +                                                         ... ...              G a r  a
                                       +4+ + 4         +44+4 +++ +
                                       ++ +                                    ++
                                       +     + +                               + 4
                                       + + +                  +
                                                       + 4 +                                                                      T-j
                                                                                                                                                             Atafona
                                                       +4 4
                                                                   +
                                             + +                     +
                                                                               i
                                       + 4             + +                                                                                                           2f*4d
                                                       +                       +                                                                        4-
                                           4 4
                                       + +                                     -
                                         +   +.        t.+ 4- +t     +                                                                                      Grussol'
                                                       +
                                       4-++ 4.                     4-          +
                                             +         -t- + ++

                                                        +        +
                                         +   +         4 4
                                       + + +                  +
                                                                                            p 0 s
                                       4-              44
                                       ++4+            + +
                                       + 4- +          ++
                                       + +- +                                  + +
                                                                                                X_
                                       4- + + +
                                                                                                                                             A
                                                       a      'cut   +         +
                                       +                                                                                                                             21*5d
                                       4- 4                          +         t,
                                       4                      +                +. +
                                                                     +
                                                                   +
                                                              +                +
                                                                   +
                                                                                                                               S
                                             4.        +
                                                       +
                                                        +
                                                       4- 4- +t-
                                         + 4- +        +
                                                                                1 2
                                       + + +. +        +
                                       * + + + "I                                 A-,
                                       4 4- +          + +    4
                                         + +           f- +                    " 1,1"1                                                                          .    WOO
                                           + + + +                              it. I., I Lawa Feic
                                         + + t + t            +    ';III       OM IIj.jI - ---------  tw,_VF=w-
                                       +t+ + 4- -f-
                                       +
                                                                                                        A
                                                                                                                                                      boo lorne
                                                                                     MI.
                                           +
                                                                                                         _A:                             Furodo oullef



                                                                                                                                                                     22nd

                                       6 0







                                                       0      10
                                                              I    I           f
                                                              km
                                                       (1) Holocene marine terraces.(Z) Lagoonal deposits. (3) Fluvial
                                                       deposits Ontraiagoonal delta), (4) Pleistocene marine ter-
                                                       raC03, (5) Barreiras Formation (Tertiary), (6) Crystalline base-
                                                       ment (Pre@cambrion), (7) Beach-ridges alignments). (8) Fluvial
                                                       paleachannels , (9) Lake&
                       Figure A-7. Geologic map of the Paraiba do Sul Delta or coastal plain. (Martin
                       and Suguio,                     1989).

                                                                                                    337










              Central and South America

              or double alignment, with a sequence of coastal lagoons at their backside.
              Araruama is the largest of these lagoons, with its mouth near the town of Cabo
              Frio. The barrier beaches follow the west direction up to the bay of Sepetiba
              near the border with the State of Sao Paulo. From this point on, and along the
              whole State of Sao Paulo, the coastline returns to its northeast- southwest
              direction, with submergence characteristics in its northern part and emergence
              characteristics in the south.     The transition between the drowned, indented
              coast, with its steep crystalline promontories, and few, narrow coastal plains,
              like Ubatuba and Caraguatatuba, and the emergence southern sector, with large
              plains up to 40 km wide (for instance, the southernmost Cananeia-Iguape plain)
              is very gradual.   The region of Sao Sebastiao forms approximately the limit
              between these zones. The width of the inner shelf also follows the trend with
              the isobath of 50 m situated at a distance of 8 km from the coastline in front
              of Santos estuary and at 50 km in front of Iguape (Suguio and Martin, 1976)
              These authors explained that such phenomenon are due to a continental flexur@
              where the inflexion axis strikes asymmetrically to the coastline.

                  The geomorphology of this region presents many diversified features (barrier
              beaches, pocket beaches, rocky shores, coastal lagoons, bays, estuaries) that
              will respond in different ways to a sea level rise.       Some locations already
              present signs of erosion, even though human interference has been minimal.

                  The mouth of Paraiba do Sul River has shown strong instability in the past
              fifteen years, with extensive erosion of the adjacent beaches and loss of valued
              property (Argento, 1989). On the southern part of the delta, the coastal plain
              shows a sequence of ridges; at the beach face, formations of grayish black
              sandstone -- humic material cemented with ferruginous oxides -- have been
              exposed, indicating a process of erosion or retrogradation. This same process
              becomes also evident by the truncated configuration of coastal lagoons on the
              back side of transgressive barriers (Dias and Silva, 1984). Similar processes
              have been identified by Muehe (1984, 1989) at the barrier beaches between Cape
              Frio and Guanabara Bay, besides evidence of erosion along the back side of the
              barrier that faces Araruama Lagoon.

                  Another point in the State of Rio de Janeiro that may suffer from a rise in
              sea level is the fluvial-marine plain along the estuary of Sao Joao River,
              located about 200 km south of Paraiba do Sul River.     At present, there is an
              extensive culture of rice along the valley, which uses the water from the river
              for irrigation purposes. Besides potential risks of flooding, the rise of sea
              level will cause a stronger saline intrusion, which has already been observed.

                  The flat areas around Guanabara Bay have flooded very often during heavy
              rains, especially along rivers and drainage canals. The combined effects of a
              rise in sea level and siltation of those canals will enhance the problem of
              flooding.  On the other hand, because the relative sea level was 5 m higher
              during the Holocene than at present, not only were beach sediments deposited
              far from the present coastline (Amador, 1974) but the terrain also became very
              flat and appropriate for marine flooding of extensive areas. Similar problems
              should affect all low-lying areas of coastal plains and river valleys.


                                                     338











                                                                           Muehe and Neves

         The South Region

              This region is formed by the States of Parana (PR), Santa Catarina (SQ, and
         Rio Grande do Sul (PS) (Figure A-8). The coastline is 1,310 km long. Along its
         northern portion, the coastal plains are narrow and less significant, having
         pocket beaches separated by rocky headlands. Paranagua Bay is the most important
         feature of this segment. Toward the south, the coastal plains gradually become
         wider, and important estuaries appear, like Guaratuba Bay (PR), the Itajai River
         (SC), and Laguna (SC), although along the coast of Santa Catarina, pocket beaches
         are very frequent.

              Reaching the State of Rio Grande do Sul, though, the coastal plain widens
         considerably, reaching 120 km for an extension of almost 520 km, being the
         largest coastal plain in the country.    This is where Patos Lagoon is located,
         which has an area of 10,000 sq. km and an average depth of 4 m, and is connected
         to the ocean through a single inlet at Rio Grande. The mild slope of the coastal
         plain extends offshore:    the 50-m deep contour is about 30 km away from the
         beach, twice as far as in Santa Catarina.

              Processes of erosion and accumulation have been reported by Angulo (1989)
         for the littoral of Parana, but observations of coastline changes were restricted
         to typically unstable areas like mouths of estuaries (a similar comment has been
         made already for Maceio, in the Northeast region).        In Santa Catarina, the
         emergence of peat at the backshore near the scarp of the barrier indicates a
         trend of retrogradation.    Tomazelli and Villwock (1989) present well-defined
         information about the presence of peat on the foreshore and along the base of
         foredunes along the beaches in Rio Grande do Sul. Erosion along the margin of
         Patos Lagoon is also interpreted by these authors as an indication of relative
         sea level rise. Due to the dominant onshore direction of local winds, a dune
         field tends to be built with sand removed from the beach. The erosive effects
         already observed might be intensified if this dune field is removed.



















                                                339










                         Central and South Awrica




                                       SOUTH REGION









                                                                                                                        BRAZIL





                                                                                                                                 PR
                                                                                                                                 sc
                                                                                    t

























                                                                  PATOS













                                                                                                                        SLAND3.111FACH RIOKSAIMES.M0004S


                                                                                                                        BEAM PONSAARIM 8EWH,0JNES,SALT
                                                                                                                        MARS"









                                                                                                                                  SCALIE
                                                                                                                                              KM



                        Figure A-8.             Classification of main physiographic features of the Brazilian
                        coastline: South Region.


                                                                                        340











       POTENTIAL IMPACTS OF SEA LEVEL RISE ON THE GUIANA COAST:
                        GUYANA, SURINAM, AND FRENCH GUIANA


                                          J.R.K. DANIEL
                                      University of Guyana
                                       Georgetown, Guyana






         ABSTRACT

              The northeastern coastal zone of the South American continent, known as the
         Guiana coast, stretches between the estuaries of the Amazon and the Orinoco
         Rivers and forms the coastline of Guyana, Surinam, French Guiana, and parts of
         Brazil and Venezuela.    The coastal strip is of varying width and is below sea
         level at high tide in most places. As a result, extensive areas are covered with
         swamps, mangrove forests, and tidal and mud flats.

              Early colonizers managed to establish plantations by draining the land.
         Because agricultural development has taken place in this zone, today over 90%
         of the population of Guyana, Surinam, and French Guiana live on the Guiana Coast.
         Therefore, most of the urban centers and communication lines are concentrated
         on the coastal zone in the three countries.

              A rise in sea     level would have serious economic and environmental
         consequences for the    Guiana coast.    The coastal stretch that is naturally
         protected by cheniers  and shell beaches is likely to recede with the rising sea
         level. Much of Guyana  and Surinam will be inundated, even if the sea level rises,
         by as little as 30 cm.

              Mechanisms are in place in both Guyana and Surinam to construct and maintain
         sea defense structures and to take emergency measures in case of breaches.     But
         long-term plans to counter the consequences of sea level rise are nonexistent
         in the three countries. The governments concerned have not taken the possible
         threat of sea level rise seriously, and the coastal communities are mostly
         unaware of the possible danger.


         INTRODUCTION

              Along the northeastern coast of South America between the mouths of the
         Amazon and the Orinoco Rivers lies a 1,600-km-long, low coast dominated by
         swamps, mangrove forests, tidal flats, mud banks, and flat coastal plains. This


                                                341











               Central and South America

               Guiana coast forms the coastline for Guyana, Surinam, French Guiana, and parts
               of Venezuela and Brazil.

                   More than 90% of the population of the Guianas live on the coastal plain.
               As a result, most of the urban centers, including the capitals, communication
               networks, and industries are concentrated there.

                   A rapid rise in sea level would inundate low-lying areas, erode the
               coastline, increase salinity of the lower courses of the rivers, disrupt coastal
               wetlands, and raise the water table. Although the heavy sedimentation that takes
               place on the Guiana coast may offset some of the erosion and wetland loss from
               a rapid sea level rise, it would do little to mitigate the other problems.

                   About 50% of the coast of Guyana is protected by sea defense structures, and
               provisions exist to take emergency measures in case of major breeches or failure
               of the sea defense system.    However, the entire coast of Surinam and French
               Guiana, and the western portion of the Guyana coast, remain in their natural
               state.



               PHYSICAL CHARACTERISTICS

               The Coastal Plain

                   The coastal plain forms a distinct geomorphological region in the Guianas.
               It occupies only a small percentage of land in each country but is considered
               an important economic zone.    It can be subdivided into two geomorphological
               regions: the young and the old coastal plains (Figure 1). The former does not
               rise more than 2.5 m above mean sea level and in places lies 1.5 m below high
               tide; the old coastal plain has an average elevation of 3 m rising to 8 m near
               its southern border. Both are underlain by clays of different periods.


               CLIMATIC CHARACTERISTICS

                   The Guiana coast has a humid tropical climate with its characteristic high
               rainfall and high temperatures. Two distinct wet periods can be recognized in
               the rainfall pattern: the first lasts from mid-May to July, and the second from
               November to January, with the former having the most rainfall.

               Marine Environment

                   The waves, in accordance with the wind direction, are northeasterly, and
               they meet the shoreline at an oblique angle. The coast may be considered as a
               low-moderate energy coast.   Unlike the Caribbean islands, the Guiana coast is
               not subjected to hurricanes and storm waves. Wave energy is considerably reduced
               off the coast of Guiana because of the presence of fine sediments, which remain
               in suspension in the near coastal area. The tide is semi-diurnal and its effects
               are felt far inland along major rivers.


                                                     342







                                                                                                                                                                                                           Daniel











                                                                                                                                                                                                     ... ...           .... ..





                         A. Guyana



                                                           Jr.



                                                       U


                                                                                                                                                                                     s







                                                                              .......           .......          ...
                                                                              .... ..           ......
                                                                                                               ....    . .......





                             B. Surinam











                                                                                                                                                                                             MOMETRES                    1 0





                                                       C.French Guiana



                                 SURFACE MATERIALS                                   FORMATION                 PERIOD


                                          Swamp


                                          Estuarine and Riverain deposits                                      HOLOCENE
                                          Solins marine clay sediments
                                          Desolinised marine cloy sediments
                                          P goes ( Pool growing above S.L. )  -
                                          M:ttledecloy sediments                     COROPINA                  PLEISTOCENE
                         2'&L    S @i@    Remnonts of old choniers I sand)    J

                                          White sands                           - BERBICE                      PLIOCENE- PLEISTOCENE
                                 7__
                                          Crystalline basement complex          -                              PRE -CAMBRIAN

                                          Coastal Plain

                      Figure 1. Geomorphology of the Guiana coast.

                                                                                                                     343








              Centra7 and South America

              Sediment Transportation and Deposition

                   It is estimated that 100 million tons of sediment are transported westward
              every year by the ocean currents. A large proportion is kept in suspension by
              the changing tidal conditions, waves, and currents.

                   When the concentration of sediment in the water exceeds a critical level,
              it flocculates to form a coherent mass of viscous mud known as sling mud, and
              settles to form mudflats on the shoreline and mudshoals in the offshore region
              (NEDECO, 1972).

                   The mudshoals influence the development of the coastline of the Guianas.
              The coast that lies directly opposite the mudshoal is protected from wave action
              because the viscous nature of the mud damps out the waves. This coast may be
              designated as an accretionary coast.     A coast that lies directly opposite a
              trough (between two mudshoals) is subject to wave erosion and may be designated
              as an erosional coast (Augustinus, 1978).   It has been shown that the mud shoals
              migrate westward at an average rate of 125 m/month and the recurrence interval
              of a mudshoal is approximately 30 years (NEDECO, 1972). Thus, at any one point,
              the coast is subjected to either accretion or erosion.

              Accretionary Coasts

                   An accretionary coast begins as a tidal flat at the landward end of a shoal
              and can extend as far as 0.8 km.     As soon as the tidal flat begins to emerge
              above the high-water level, mangrove establishes itself and stabilizes the flat.
              The mud that emerges above the high-water level is subjected to physical,
              chemical, and biological ripening, leading to soil formation favoring other
              vegetation types in addition to mangrove.

                   Sand accretionary coasts are rare, and where they do occur, they are not
              as extensive as the clay accretionary coasts. Cheniers are -extensively developed
              on the Guiana coast. Stretches of beaches entirely composed of shell fragments
              occur in several places along the northwestern coast of Guyana.

              Erosional Coasts

                   Erosional coasts lie opposite a trough (between two mudshoals). When the
              eastern end of a mudshoal is eroded, the coast directly opposite it increasingly
              comes under wave action. Erosion on the shoreline begins at the edge of the mud
              flat. As the mud flat is gradually eroded, waves are able to come closer to the
              coast.  The removal of mud exposes the root system of the mangrove to wave
              action, which eventually destroys the vegetation. Since the seedlings of the
              mangrove are not adapted to development under continuous inundation they are not
              replenished.    Once mangrove is destroyed, erosion of the coast proceeds
              unhindered.

              Vegetation and Fauna

                   Mangrove vegetation fringes the shoreline of the Guiana coast. Either a
              herbaceous swamp or a swamp forest occurs behind the mangrove.        The largest
              swamp is located between the Pomoroon and Orinoco Rivers.

                                                     344









                                                                                      Danie7

              The wetlands on the Guiana coast have an exotic variety of animals, birds,
         insects, and marine life. The northwest coast is one of the breeding grounds
         for the scarlet ibis and many other birds.      In the nearshore region, several
         shrimp species and two species of crabs are common. The northwestern coast is
         the annual nesting grounds for at least four types of giant sea turtles
         considered to be endangered species:        greens,   hawksbills,   Ridleys,    and
         leatherbacks.   In the numerous canals and drainage ditches, freshwater fish
         abound.

         Groundwater Resources

              The geologic formation of the Guiana Shield favors the occurrence of
         groundwater on the coastal plain.    More than 90% of the potable water on the
         Guyana coast is obtained from two aquifers that occur at two levels.            The
         groundwater recharge area is the exposed portion of the white sand that underlies
         the rolling hills south of the coastal plain.


         AGRICULTURAL AND ECONOMIC DEVELOPMENT

         Agriculture

              The predominant economic activity on the Guiana coast is agriculture,
         followed by fishing. The coastal belt has favorable soil and climate for lowland
         crops, such as sugarcane and rice. Among the three countries, Guyana has the
         most cultivated land (Figure 2).       In both Guyana and Surinam, almost all
         agricultural activities are confined to the coastal belt.       Apart from market
         gardening near large cities, agriculture is insignificant in French Guiana.

              Agriculture is the major source of employment, economic growth, and foreign
         exchange in the Guyanese economy (Table 1).     Most of the irrigation and land
         development programs are geared to two major crops, sugarcane and rice. Since
         fertile agricultural land is located very close to the coast, large sums of funds
         are allocated for drainage, irrigation, and sea defense works.

              The,land use pattern on the coastal belt of Surinam is similar to that of
         Guyana, but in Surinam agriculture contributes only 9.1% of the Gross Domestic
         Product (GDP).

              In French Guiana, the main occupation on the coast is fishing, which
         constitutes 59.3% of all exports.    Very few food crops are produced in French
         Guiana. Being an overseas territory of France, most of its food is imported.


         POPULATION DISTRIBUTION

              Over 90% of the population of the three countries live on the Guiana coast
         (Table 2). The capitals are also located on the coast, as are major towns and
         urban centers.

              The main communication lines of the three countries are along the coast.
         Since most of the rivers on the Guiana Shield flow in a south to north direction,

                                                345












                                                                                                                            A
                                                                                                             ww@
                                  01
                                 'Ir
                               t

                                                                                                                              4r



                                                          V..


                           A. Guyana




                                                             N' KERIE


                                                                                                                                        A 190
                                                                             AGE
                                                                                RINGER
                                                                                                                    L FRANCOM
                                                                                                        JERRY.





                                                                                                                                           ZANDERIJ





                                                                            NO."

                                                                                                                                                    BROKOPONDO



                             B. Surinam






                                                                            Wft@ R,w,.


                                                                                                          IRACOU110
                                                                        S, LAURENT








                                                                                                                                                CAYENK


                                                     C. French Guiana



                                  CULTIVATED LAND                            S       AIRPORT/ AIRSTRIP                                                        RAW.

                                  BAUXITE PRODUCING AREA                             FISHERIES

                                  COMMERCIAL TIMBER PRODUCTION                       TOURISM
                                  GOLD PRODUCING AREA                                :PACE CENTRE
                                  MANGANESE DEPOSIT                                  IL WELL                   0     PUL?METRES   50
                                  GOLD EXPLOITATION                                  ROAD

                                  BAUXITE EXPLOITATION                               RAILWAY

                                  REFORESTATION                                      DISUSED RAILWAY

                                  LIVESTOC
                                  NATURE R:SERVE
                          Figure 2. Land use of                             the      Guiana coast.


                                                                                                           346









                                                                                      Daniel

                                Table 1. Agricultural Development


             Component                 Guyana         Surinam       French Guiana


        Total population               756,000        354,860           85,700

        Area (km')                     214,969        163,265           90,000

        Agriculture contribution
          to GDP(%)                      29.0           9.1              N.A.

        Total cultivated land (ha)     242,817          36,000           3,000

        Irrigated land (ha)            161,818          20,000           N.A.

        Sugarcane (metric tons)      3,520,000        150,000            5,000

        Rice (metric tons)             300,000        270,000            7,790

        Fish catches                     27,600          3,600           1,400

        N.A. = Not available.


        ferry service and other forms of river transportation are provided at major river
        crossings.

             With the exception of the bauxite processing industry in Linden (Guyana)
        and Brokopondo (Surinam), all the major industries and factories are located on
        the coastal belt, particularly in the capitals and port cities.


        EFFECTS OF SEA LEVEL RISE

        Methodology

             To estimate erosion from 50-, 100-, and 200-cm sea level rise scenarios,
        we used the Bruun Rule:

                                                             al
                                                       S I -
                                                              h

        where S = approximation of shoreline movement, a = rise in sea level, h = maximum
        depth of exchange of material between the nearshore and the offshore, and I
        length of the profile of exchange.

             On the Guiana coast, the sea bottom profile in the nearshore zone is shaped
        by the wave action to a depth of 2 meters (NEDECO, 1972). The orbital motion
        of waves is reduced to an almost horizontal to-and-fro movement. Wave velocity

                                                347








             Central and South America

                     Table 2. Population of Cities/Towns Located on the Guiana Coast

                                                                            Distance from
                City/Town                     Population                    the coast (km)


             Georgetown'                        56,095                              0

             New Amsterdam                      19,287                              8

             Rose Hall                            3,167                             0

             Corriverton                        18,617                              0

             Paramaribo (1987)                  68,617                              7.5

             Nickerie                            8,000                              11

             Cayenne (1988)                     19,688                              0

             St. Laurent                         3,486                              27

             aUnless otherwise noted all values are for 1981.


             exceeds 0.70 m/sec, a critical velocity that is required to initiate erosion on
             the sea bottom (Augustinus, 1978). Therefore for convenience, the maximum depth
             of exchange of material between the nearshore and offshore (h) is taken as 2
             meters.

                  The average distance between the 2-meter bathymetry. and the shoreline is
             about 300 meters, but it varies according to the position of the mudshoals. To
             determine the length of the profile of exchange (1), distances between the
             2-meter bathymetry and the shoreline were measured at intervals of 20 kilometers
             along the coastline on the map (scale 1:1,000,000).


             RESULTS

             Scenarios

                  Projected coastline positions for a 50-, 100- and 200-cm rise in sea level
             are shown in Figure 3(A-C).        The future coastline shown here is highly
             generalized because of the small scale (1:1,000,000) of the map. Based on the
             EPA study of sea level rise (Titus, 1985), two scenarios, the mid-range high and
             mid-range low -- henceforth simply referred to as high and low, respectively -
             - were selected. Measurements taken from the map were compiled under the two
             scenarios to show the future rate of coastal erosion. They were also compared
             with both short-term and long-term historical rates of erosion (Table 3). The
             latest available maps were published in 1980.      Therefore, 1980 was considered
             the baseline.


                                                     348



























                        %00

                                                                ... .......
                                                                                                                                                ----------












             (A)
             4@b                             U
             to








                                                               1 Orn Depth Contour (Closure Point)

                                                    Change in Sea Level

                                                       .......... 50cm Rise
                                                               100cm Rise
                                                       ------- 200cm Rise





                       Figure 3A. Scenarios of sea level rise for Guyana.











                                            L  . . . . . ......


                                                                              Ilk .......... ..










                                                                          U R      I N






                                                     lorn Depth Contour (Closure Point)

                                            Change in Sea Level

                                               .......... 50cm Rise

                                               ------ I 00cm Rise

                                               ------- 200cm Rise





                     Figure 3B.     Scenarios of sea level rise for Surinam.











                                                                                                  GU/41V
                                                                                                             4










                                                     10m Depth Contour (Closure Point)

                                           Change in Sea Level

                                              .......... 50cm Rise
                                              ------ 1 00cm Rise
                                              ------- 200cm Rise




                   Figure 3C. Scenarios of sea level rise for French Guiana.









                      Centra7 and South America

           Table 3. Projected Recession on the Guiana Coast (Meters of shoreline retreat relative to its
                          current position)

                                                                                                                Historical records
                                       50 cm                100 cm               200 cm
                                 Total shoreline      Total shoreline      Total shoreline       Mid-term           Long-term
                                    retreat (m)         retreat (m)          retreat (m)        @,historical        historical       Historical
                                                                                                record (m/y)      record (shill) record (shiU)
                  Coasts                                                                           1942-49           1942-66          1830-1980



           Wainini-Pomoroon            1200                 2400                 4800


           Pomoroon-
             Essequibo Estuary         2500                 5200                 10300              12                10-15

           Essequibo Estuary*          --------------- sea  defense -------------------7              5

           Essequibo-Demerara*         --------------- sea  defense --------------------              5

           Demerara-Mahaica*           --------------- sea  defense --------------------            10-20


           Mahaica-Berbice             1100                 2200                 4300               28                15-25              6.2

           Berbice-Corentyne           900                  1800                 3660               27                 8-15

           Corentyne-
             Coppename                 350                  700                  1400               20

           Coppename-
             Surinam                   1200                 2300                 4600                 4               15


           Surinam-Maroni              900                  1800                 3600


           Maroni-Sinnemary            500                  1100                 2200

           Sinnemary-Cayenne           400                  900                  1750

           Cayenne-Oyapock             600                  1200                 2400

             We assume no erosion in   areas that already   have sea defenses.


                             Since     the erosional environment on the coast varies significantly, each
                      coastal segment between the major rivers is treated separately. A 50-cm scenario
                      forecast would affect almost the entire coast. Further rise in sea level would
                      only exacerbate the situation. Therefore, the scenario for a 50-cm rise in sea
                      level is considered in detail.


                      50-cm Scenario

                             For a 50-cm rise in sea level, it is estimated that the wetland loss would
                      be highest along the northwestern coast of Guyana. Several factors lead to this
                      conclusion.          The tidal range is very low in this area, which implies that
                      existing wetlands are at low elevations. The area is also very flat and has many
                      water courses. Above all, the area is subject to subsidence. Despite the high
                      rate of peat growth and sedimentation, until recently the relative rate of sea
                      level has been rising in the area (Brinkman and.Pons, 1968).


                                                                              352











                                                                                    Daniel


             Being sparsely populated with little or no development or infrastructure,
        the effects of sea level rise would be minimal compared to the densely populated
        coasts. The wetlands would simply migrate landward, as the coastland is very
        low and occupies a large area.

             Saltwater intrusion would also disrupt the swamps since they lie at the
        same elevation as the mangrove. A rise in the water table would convert most
        of the low-lying swamps to brackish, open-water environments.

             The estuaries generally have maintained a fairly stable shoreline on the
        Guiana coast (NEDECO, 1972). The estuarine areas receive much more sediment than
        the coasts. Erosion is balanced by sedimentation on the larger islands in the
        estuary (Daniel, 1984). However, the estuarine coasts facing the northeastern
        direction would be affected by the increased wave velocity when sea level rises
        to 50 cm.

             Wetland loss would be greater along the coast where sea defenses exist.
        With the erosion of the mangrove and the tidal flats, large waves would be able
        to approach the seawall more frequently, thereby increasing the pressure on the
        seawall and increasing the incidents of overtopping.     Laboratory studies have
        indicated that if the sea level rises by as little as 30 cm, overtopping would
        increase threefold (NEDECO, 1972). Saltwater intrusion in the rivers and creeks
        is also likely to increase with rising sea level.

             Western Surinam, particularly the area adjacent to the mouth of the
        Corentyne River, has development similar to the eastern coast of Guyana. Rice
        cultivation is extensive and, with improvement of drainage and irrigation, is
        expanding.   Several acres of swamps have been drained and converted to rice
        cultivation.

             Most of the urban and agricultural development in Surinam is located on a
        chain of cheniers that occurs farther inland. The vast swamp that exists between
        the cheniers and the coast is undisturbed. Furthermore, several hectares of land
        on the coast are preserved as nature reserves. Therefore higher sea levels would
        simply cause the wetland to migrate inland.

             In French Guiana, a 50-cm rise in sea level implies a very low erosion rate.
        This area experienced a slight uplift in the past (Brinkman and Pons, 1968).
        A few islands that lie in the offshore area are underlain by resistant
        crystalline basement rocks. Since the extent of the lowland is limited by the
        rapidly rising land southward, wetland loss would be proportionately higher on
        this coast than elsewhere. Initial sea level rise is likely to affect only the
        mangrove-fringed coast. Other problems associated with sea level rise, such as
        higher water table and increased salinity in the surface and groundwater, can
        also be expected, although economic loss is not likely to be significant.

             A slightly higher erosion rate is forecast for the coast east of Cayenne,
        an area also subject to subsidence (Brinkman and Pons, 1968). If the subsidence


                                               353











              Central and South America

              continues, erosion is likely to be greater. Because of sparse settlements in
              the region, very little economic development has taken place.

              100-cm Scenario

                   A 100-cm rise in sea level for a high scenario would occur by the year 2062
              according to the EPA estimates, and a low scenario as interpolated from the EPA
              estimate would occur by the year 2080.     On the northwestern coast of Guyana,
              further encroachment of swamps by mangrove vegetation can be expected.

                   Total land loss would be great (over 5,000 M)*; Along the eastern part of
              the Guyana coast and parts of Surinam coast, land loss would be considerable
              (over 2,000 m) and much farmland would be affected.'

                   The area most affected would invariably be the coast that is protected,
              unless foreshore erosion is prevented. Mangrove in the foreshore area in front
              of the sea defense structures will be completely wiped out by the rising sea
              level. Georgetown, a city that is well fortified against sea erosion, is likely
              to come under increasing pressure as the sea level rises.

              200-cm Scenario

                   A 200-cm rise in sea level for a high scenario would occur by the year 2095
              and for a low scenario in 220 years' time, as interpolated from the EPA
              estimates. The effects of a sea level rise of this magnitude are difficult to
              determine at this time.    On a few unprotected coasts, strips of land up to a
              kilometer wide would be permanently inundated, forcing the mangrove to migrate
              landward, and swamp vegetation would be drastically changed. The lower courses
              of several rivers that flow parallel to the coast would be altered as the land
              separating the river channels from the  coast is eroded away. Urban development
              and roadways previously located on the unprotected sections of the coast would
              have been relocated on the old coastal plain.

                   Major cities and towns protected against sea erosion would have embarked
              on a beach fill program, and perhaps a few kilometers of breakwater would have
              been built, but the costs of such       programs would be prohibitively high.
              Increasing problems in sewage disposal, stormwater disposal, rising water table,
              and saltwater intrusion in the cities   would be enormous.    The effects of sea
              level rise described previously would be exacerbated. Some coastal settlements
              have already experienced some of these effects, although not necessarily due to
              rising sea level.

                   Sedimentation along the coast may partially offset the effects of wetland
              loss, but sedimentation occurs unevenly along the coast and is influenced by a
              cyclic pattern, resulting in net decrease of land area. The scenarios forecast
              in this study do not take into consideration the possible effects of
              sedimentation.   Calmer sea conditions have caused heavy sedimentation on the
              Guiana coast in the past.     Furthermore, at the mouth of the Amazon River,
              suspended solids increase as much as fivefold during the wet period compared with
              the dry period (Gibbs, 1967).     Thus, an increase in discharge in the Amazon

                                                     354











                                                                                    Daniel

         system through increased rainfall or increased deforestation and runoff could
         supply more sediments.


         PAST TRENDS IN RECESSION

             Contradictory views have been expressed on the severity of erosion on the
         Guiana coast. NEDECO (1972) concluded that there had been a net erosion on the
         Guiana coast.   On the other hand, the Hydraulics Research Station (HRS) at
         Wallingford refuted this claim. In a recent study, Augustinus and Mees (1984)
         claimed that the coast of Guiana has been receding.

             Based on the positions of cheniers, NEDECO (1972) calculated that the coast
         of Guyana was receding at the rate of 20 m/year and the Surinam coast was
         receding at the rate of 12 m/year between 1947/48 and 1957, and 8.5 m/year
         between the years 1957 and 1966. Augustinus and Mees (1982) also observed that
         on the Surinam coast, erosion has diminished and accretion has taken place. On
         the whole, recession has averaged 10-30 m/year on the Guiana coast.        NEDECO
         (1972) observed that with the rise of sea level in the past century, the 10-30
         m/year historical rate of erosion has accelerated in recent years. Various rates
         of erosion calculated by NEDECO are given in Table 3.

             Historical records also show that the shore has advanced along some coasts.
         For example, at Pt. Isere (French Guiana) and Totness (Surinam), rapid accretion
         has taken place.

             Seawalls do not always prevent erosion.      Although the coast may appear
         visibly stabilized after the construction of a seawall, erosion can continue in
         the foreshore area. NEDECO demonstrated that the foreshore area is oversteepened
         where sea defense structures exist. Augustinus and Mees (1984) attributed the
         receding shoreline in Guyana to the lack of mangrove development.

             Seawalls without adequate toe slope protection are particularly prone to
         oversteepening of the foreshore and the eventual collapse of the seawall itself.
         This happened in Clonbrook near the Mahaica River mouth, where a 152-meter
         section of seawall sank more than 0.6 meters after the foundation collapsed into
         the sea (Starbroek News, 1989a).


         RESPONSES

         Guyana

             In Guyana, settlement has meant a constant battle against the sea.        The
         settlers built artificial dams and sluice gates between the naturally occurring
         cheniers to form a defense against erosion.

             Because of the complexity of the coastal processes and their effect on the
         low-lying areas for the past four decades, successive governments in Guyana have
         sought the help of international consultants to study the coast.        Two such

                                               355











              Centra7 and South America

              consultants, NEDECO and HRS, made in-depth studies of the coastal problems. The
              former also studied Surinam's coastal problems. The two consultants perceived
              the coastal problems differently and suggested conflicting strategies (Daniel,
              1988).

                  NEDECO's model for the Guiana coast predicted a 30-year cycle of erosion
              and accretion with a net land loss of 10-30 meters annually. They observed that
              strengthening the seawall at the present site would not help, because the
              accelerated erosion in the foreshore region would eventually undermine the sea-
              wall . They recommended a seawall of a different design for the priority areas,
              such as Georgetown and its environs. The priority areas were determined on the
              basis of a cost-benefit analysis.    In the low-priority areas, such as rural
              areas, a new seawall several meters inland from the present sea defense system
              was suggested.     This simply means abandoning several acres of valuable
              agricultural land fronting the coast.

                  Based on economic, statistical, and historical data, HRS suggested that
              Guyana should be prepared to respond to emergencies rather than build a strong
              sea defense system and supported the present policy of strengthening the sea
              defense as and when necessary.

                  Comparing the two reports, it is clear that NEDECO'S suggestions are valid
              in light of the accelerated sea level rise.     HRS's report is based on more
              conservative estimates and does not take into consideration the possibility of
              future sea level rise.

                  The seawall has to be considerably strengthened and raised to counter the
              effect of rising sea level. Other defensive measures would include increasing
              the toe slope on the seaward side and systematic beach filling.         On some
              vulnerable coasts these measures have already been taken. The present height
              and width of seawalls is determined according to the cost factor. Overtopping,
              even at present levels, is not desirable, but because of the high costs, they
              are so designed. Raising the seawall by as little as 30 cm would increase the
              cost so exorbitantly that a country like Guyana could ill afford it.

                  A plan proposed by NEDECO (1972) to build a breakwater to the city's
              coastline may have to be implemented. A beach fill scheme would also lessen the
              problem.

                  Disposal of sewage in densely populated urban centers would pose severe
              probl ems when the water tabl e ri ses al ong wi th the ri s i ng sea 1 evel . At present,
              a majority of houses are equipped with septic tanks. A rise in the water table
              would render most of them useless, unless drainage is drastically improved.

                  In the eastern part of Guyana, where most of the agricultural land is
              located, a well-integrated plan will have to be implemented to counter the
              effects of sea level rise. Sections of seawall will have to be rehabilitated
              and drainage facilities improved.



                                                    356











                                                                                   Daniel

            At present, Guyana is equipped to take emergency measures in the event of
        breaches in the sea defense system. The Hydraulics Division of the Ministry of
        Agriculture is responsible for the maintenance of the sea defense system. It can
        obtain resources from the government and the private sector without legislative
        approval to incur expenses under "force account" to repair seawalls and contain
        flow whenever necessary.

            Routine surveillance and maintenance work is carried out by the regional
        councils, but they do not carry out major repairs.          Increasing problems
        associated with shortages of manpower, materials, machinery, and funds have
        prompted the government to reconsider centralization of sea defense.

            Although the government is prepared to take emergency measures for sea
        defense, a rapid sea level rise in the future and its potential impact are not
        envisaged by the engineers. The problem of coastal erosion is perceived simply
        as a cycle of erosion and accretion associated with the movement of mudshoals
        in the nearshore region.

            The Ministry of Housing, which regulates land use and implements housing
        policies, does not restrict the construction of buildings near the seawall.    In
        Georgetown, some houses are less than 15 meters from the seawall.           Major
        government and private housing developments are located close to the seawall in
        Enterprise, Nuitenzuil, Success, Lusignan, and along many parts of the coast.
        The Ministry does not perceive the possible sea level rise to be an immediate
        threat and has no policies to curb the construction of buildings close to the
        seawall.

            Similarly, the Guyana Water Authority (GUYWA), which controls the
        distribution of potable water in Guyana, does not have a policy to deal with the
        impact of future sea level rise on water resources.       Even records of water
        quality, transmissivity, recharge rates, and discharge rates of each well site
        are not kept. Such data are obtained only when major surveys are carried out.
        The last major survey was carried out by Worts in 1958.

            Mining of sand from the cheniers is prohibited by law, a measure that would
        prevent accelerated erosion. Similarly, several species of animals and birds
        that take sanctuary in the coastal swamps and forests are included among the
        endangered species specified in the Guyana Wild Life Preservation Act.        The
        recently formed Guyana Agency for Health Education and Food Policy is required
        to review all.development projects and submit environmental impact reports. Its
        function is similar to that of the U.S. Environmental Protection Agency. Despite
        all of these developments, there is no coherent policy to take countermeasures
        against the possible rise of sea level in the future.

            Coastal dwellers who live in areas that are repeatedly affected by erosion
        and flooding are fully aware of the implications of a failure in the sea defense
        system, but are unable to perceive the larger problem of sea level rise because
        of lack of information. Recently, the possible threat of sea level rise and its
        possible consequences were mentioned at two regional conferences held in Guyana.
        The Commonwealth Secretariat also has completed a study on Guyana's coast and

                                              357











              Central and South America

              has warned the government of the possible consequences of sea level rise. These
              recent developments have helped the government to perceive more clearly the
              problem of sea level rise.

              Surinam

                  Surinam's land development on the coast has followed a pattern similar to
              that of Guyana.    Most of its agricultural land is restricted to the coastal
              plain.   But unlike Guyana, it is not close to the coastline.            Therefore,
              extensive flood control and sea defense were unnecessary. In addition, Surinam's
              coast is fairly stable, and coastal erosion is not,as-acute as on the coast of
              Guyana.

                  The western Surinam coast, east of the Corentyne River where a large area
              i-s under rice cultivation, is considered a stable area. The small farmers who
              hold less then 4 hectares of land are mostly located along the rivers in
              Comowijne and Surinam. Therefore, farmers in Surinam do not encounter erosion
              and flooding as frequently as their Guyanese counterparts.      They are not used
              to perceiving the sea as a threat. However, an increase in sea level may cause
              the rivers to overflow and damage low-lying rice farms.

                  Because large areas along the coast have been preserved as nature reserves
              and Paramaribo is located several kilometers from the coast, the Surinamese do
              not seriously consider the effects of sea level rise.           Nevertheless, the
              administration in Surinam commissioned NEDECO (1968) to study erosion along the
              coast. NEDECO later conducted a more elaborate survey of the entire Guiana coast
              (1972).

                  Surinam follows a vigorous environmental policy. Several organizations in
              Surinam have carried out joint surveys with their Dutch counterparts on various
              aspects of the environment.     The Soil Survey Department of the Ministry of
              Natural Resources has carried out research in collaboration with the Soil Survey
              Laboratory of Wageningen, the Netherlands, on soil and erosion along the coast.
              The Dutch navy has conducted hydrographic.surveys off the coast of Surinam and
              a Dutch engineering firm has been dredging the rivers frequently.               The
              International Maritime Organization (IMO) has also been conducting studies in
              Surinam waters, as well as in Guyana and French Guiana. The Department of Lands
              and Surveys and Aerial Photography has compiled maps of the coastal area based
              on aerial photographs taken at regular intervals, and the Ministry of Agriculture
              and Fisheries and the Department of Surveys of Waterways and Water Courses have
              also tarried out several hydrologic studies.

                  Since the coastal problem in Surinam is not as acute as in Guyana, there
              is hardly any awareness among the coastal dwellers about the possible danger of
              sea level rise.     Because Surinam collaborates closely with several Dutch
              organizations, it would not be difficult for the' government to take
              countermeasures against the impacts of sea level rise when the need arises.




                                                     358











                                                                                     DanW

          French Guiana

              Economically, French Guiana would be least affected by a future rise in sea
          level. But physically it could suffer extensive losses of wetland areas.

              The coastal area is included in the Cayenne arrondissement (district)
          according to administrative divisions. It is subdivided into 14 communes, the
          smallest French division.   Each commune is no more than a village with basic
          facilities, such as running water. Most decisions are made in Cayenne, if not
          in Paris.   Being an Overseas Department of France, French Guiana is totally
          dependent on the metropole. Modern ideas on the environment, greenhouse effect,
          future rise in sea level, etc., hardly trickle down to Cayenne. It still remains
          in its colonial lassitude. The only modern development has been the construction
          of a space center at Korou.

              Few studies of the environment have been carried out in French Guiana.
          Studies conducted along the Guiana coast by international consulting firms have
          included the offshore region of French Guiana.        The French navy also has
          conducted regular hydrographic surveys off the coast of French Guiana. Any long-
          term plan of action to counter the effects of sea level rise would have to
          originate from France.    Unless urban centers along the coast are seriously
          threatened, responses from the administration in French Guiana are unlikely.


          CONCLUSION

              A rise in sea level, predicted as a result of global warming processes,
          would severely affect the low-lying areas of the Guiana coast. They would be
          affected by wetland losses, coastal erosion, a rise in the water table, and
          saltwater intrusion into surface water and groundwater resources.

              These impacts would vary along the entire length of the coast. Most parts
          of Guyana would be affected because its coast lies below high water level. The
          northwestern coast would be the most affected because of subsidence. The area
          east of the Essequibo River, where most of the cultivation takes place, is
          protected against wave erosion by some form of sea defense, ranging from concrete
          seawalls to the naturally occurring cheniers.     Wetland loss in the foreshore
          area of this coast would be considerable, and the pressure on manmade sea defense
          structures would increase even under a low scenario forecast for a 50-cm rise
          in sea level.

              Most of Surinam's coast is fringed by mangrove, and parts of it are formal
          nature reserves.   Furthermore, erosion is not as severe as on the coast of
          Guyana. Under a low scenario forecast for a 50-cm rise, wetlands would migrate
          inland. Wetland losses in French Guiana would be higher because low-lying areas
          are limited.   But economic losses would be minimal because its coast remains
          largely undeveloped.

              In general, the responses to the accelerated sea level rise in the region
          are poor. Although Guyana's coastal dwellers have been battling the sea since

                                                359











                Central and South America

                the colonial period, such problems as erosion and flooding are perceived as local
                phenomena. Few government organizations or local inhabitants consider the future
                rise of sea level to be a serious threat. Recently, however, concern about the
                consequences of future sea level rise has been shown at higher government levels.
                Nevertheless, no efforts have been made to restrict developments along the
                coastal highway.

                    In Surinam and French Guiana, the possible effects of sea level rise are
                not seriously considered because most economic development, with few exceptions,
                has largely taken place away from the coastline. Coastal dwellers in both these
                countries do not endure as many problems as their Guyanese counterparts, and are
                therefore less vulnerable.



                BIBLIOGRAPHY

                Augustinus, P.G.E.F. 1978. The changing shoreline of Surinam (South America).
                Ph.D. Thesis Publication No. 95, Foundation for Scientific Research in Surinam
                and The Netherlands Antilles, The Netherlands: University of Utrecht, 232p.

                Augustinus, P.G.E.F. 1982. Coastal changes in Surinam since 1948. Proceedings
                Furoris Congress on Future of Roads and Rivers in Surinam and Neighbouring
                Region.   University of Surinam.        The Netherlands: The Delft University of
                Technology, pp. 329-338.

                Augustinus, R.G.F.G., and R.P.R. Mees.         1984.   Coastal erosion and coastal
                accretion between the estuaries of the Corentyne and the Essequibo Rivers: A
                contribution to the coastal defense in the Republic of Guyana. The Netherlands:
                State University of Utrecht, Laboratory for Physical Geography.

                Brinkman, R., and L.J. Pons. 1968. A pedo-geomorphological classification and
                map of the Holocene sediments in the coastal plain of the three Guianas. Paper
                No. 4. Wageni-ngen, The Netherlands: The Soil Survey Institute.

                Daniel, J.R.K.    1984.   Geomorphology of Guyana.      Occasional paper.     Dept. of
                Geography, University of Guyana. Release Books, 72p.

                Daniel, J.R.K. 1988. Sea defense strategies and their impact on a coast subject
                to a cyclic pattern of erosion and accretion. Ocean and Shoreline Management
                2:159-175.

                Gibbs, R.J. 1967. The geochemistry of the Amazon River System: Part 1. The
                factors that control the salinity and the composition and concentration of the
                suspended solids. Bull. Geol. Soc. Am. 78:1203-1232.

                NEDECO. 1968. Surinam transportation study. Report on hydraulic investigation.
                The Hague, The Netherlands:      Netherlands Engineering Development Consultants,
                293 p.



                                                         360











                                                                                           Daniel

           NEDECO.   1972.   Report on sea defence studies.       The Hague, The Netherlands:
           Netherlands Engineering Development Consultants,

           Starbroek News. 1989a. News item, May 3, 1989. Guyana Publications Ltd.

           Titus, J.G.    1985.   Sea level rise and the Maryland coast.         In:    Potential
           Impacts of Sea Level Rise on the Beach at Ocean City, Maryland. J.G. Titus et
           al., eds. Washington, DC: U.S. Environmental Protection Agency, p. 1-32.








































                                                    361










               IMPACTS OF SEA LEVEL RISE ON THE ARGENTINE COAST


                                          ENRIQUE J. SCHNACK
                              Laboratorio de Oceanografia Costera
                                  Facultad de Ciencias Naturales
                                C.C. 45, 1900 La Plata, Argentina

                                           JORGE L. FASANO
                   CIC y Centro de Geologia de Costas y del Cuaternario
                             Universidad Nacional de Mar del Plata
                          Funes 3350, 7600 Mar del Plata, Argentina

                                                   and


                                         NESTOR W. LANFREDI
                                            JORGE L. POUSA
                        CIC y Facultad de Ciencias Naturales y Museo
                                Universidad Nacional de La Plata
                          Paseo del Bosque, 1900 La Plata, Argentina




           ABSTRACT

                The Argentine coast exhibits a variety of environmental settings, including
           estuarine and deltaic areas, marshes, sandy and pebbly shores, and cliff
           exposures. Different wave and tide regimes operate along the coast.

                Although erosion typifies much of the nation's 5,000-kilometer coastline,
           these problems are particularly severe in the Province of Buenos Aires with 40%
           of the country's total population and one third of its coastline. The main urban
           developments, harbors, industrial complexes, and tourist resorts are located in
           this province.    Floods are very dramatic on the Rio de la Plata shores, which
           have the highest population density. Here the water level rose 4.75 m in 1940
           and 3.85 m in 1958.    In the latter case, more than a half million inhabitants
           were affected in different ways.      The Coriolis effect has been regarded as a
           major cause for the storm surges on the Argentine side of the Rio de la Plata.

                South of the Rio de la Plata, the oceanic shorelines show dissipative
           characteristics with a significant littoral drift (between 400,000 and I million
           m3/year).  There is high erosion in many areas; for exdmple, the Mar Chiquita
           beach has been retreating more than 5 m/year during the last three decades.
           Beach-sand mining for construction also contributes to erosion. Unplanned urban


                                                   363











              Centra7 and South America

              development can also account for property loss and damage. At Mar del Plata, the
              main tourist resort in Argentina, groins, jetties, and seawalls have been
              constructed since the beginning of the century without the utilization of basic
              geomorphological information, thereby partially solving local problems but
              increasing erosion along downdrift areas.

                   Fifteen tide-gauge stations, a few of them with extensive records, are
              distributed along the Argentine coast. The 64-year record of Puerto Quequen,
              located 120 km southwest of Mar del Plata, shows a rise in sea level of 16.09
              cm/100 years.   This locality seems to be the most reliable, in terms of both
              historic data and tectonic stability.

                   Coastal plain flooding is also critical in areas such as the Rio Salado
              Basin, where topographic gradients are extremely low and the phreatic surface is
              very shallow. In addition, salt intrusion of coastal aquifers can be predicted
              as a combined result of sea level rise and coastal retreat.      Overpumping has
              already created this type of problem in the city of Mar del Plata.

                   Urban development on the sandy coastline of the northern Buenos Aires
              Province has caused the elimination of extensive sand dunes, which are the only
              available storage bodies for groundwater. Beach erosion in this area is partly
              due to the restriction in sediment supply from the sand dunes.

                   The accelerated rate in sea level rise predicted for the next century will
              exacerbate the described processes. Although several impacts can be predicted
              for the Patagonian coast, they are far less dramatic than those in the northern
              coast because of the much lower population density and urban/industrial
              development.

                   In the absence of a general legal/organizational framework, institutional
              responses to coastal problems are limited to specifically oriented government
              offices, mostly at the provincial level (e.g., hydraulic departments, water
              resources agencies). Some municipal counties backed by community organizations
              are i nvol ved i n deal i ng wi th the devel opment and management of coastal resources ,
              although they usually lack expertise. It is expected that future efforts, based
              upon scientific evidence, will result in the adoption of legal and administrative
              procedures for proper use and protection of the coastal zone.


              INTRODUCTION

                   In recent years, increasing atmospheric concentrations of CO, and other
              greenhouse gases is producing a global warming, which could expand ocean water
              and melt polar ice sheets. Predictions of future sea level rise suggest a 1-m
              rise within the next 60 to.150 years (Hoffman, 1984). Estimates of future sea
              level rise vary according to the relative contribution of different factors
              involved (thermal expansion, retreat of alpine glaciers, melting of the Greenland
              and Antarctic ice-sheets). Gornitz et al. (1982) established that "eustatic" sea
              level is presently rising at a rate that exceeds 1 mm/year.


                                                    364










                                                                                Schnack, et al.

                Lanfredi et al. (1988) have estimated that sea level is currently rising
          1.6-mm/year in Puerto Quequen, which probably has the only reliable tide-gauge
          station in Argentina.     This station has a 64-year record and is located in a
          tectonically stable area, which allows for a true eustatic component to be
          considered.

                Even without considering the present or predicted rates in sea level rise,
          the Argentine coastal areas are undergoing several impacts (shore erosion, salt
          intrusion, pollution, etc.) as a response to both natural and predominantly
          human-induced processes. If the rate of sea level rise were to accelerate as
          predicted, it would be necessary to adopt policies and management regulations to
          adequately deal with it.       Government and community structures would play an
          important role in this regard.


          CHARACTERIZATION


          Natural Features

                According to the Koeppen climatic system, the Argentine coast is temperate
          from the Parana Delta down to 40 km SW of the Rio Negro, arid from there to Rio
          Gallegos, and "cold humid" to the south of that location.

                The coastline of Argentina is about 5,700 km long (Figure 1), not including
          the Malvinas and Antartica.        (Note:   While Argentina claims both of these
          sectors, the United Kingdom currently administers the Malvinas (Falkland Islands)
          and Argentine ownership of the Antarctica sector is not universally recognized.)
          A very wide continental shelf extends offshore, reaching in some places, over 800
          km in width. Main coastal landforms (Figure 1) are deltas, estuaries, marshes,
          cliffs and wave-cut terraces, sandy and pebbly shores, and ice-fringed coastlines
          (Antarctic area). Sandy coastlines are typical along the strip extending from
          Cabo San Antonio to Mar Chiquita Lagoon, in northeastern Argentina, where a 150-
          km-long barrier develops.        In this area, the shoreline shows dissipative
          characteristics with a significant littoral drift (between 400,000 and I million
          m'/year). Figure 2 illustrates a number of coastal features.

                Pebbles are a typical component of the Patagonian shores. They originate
          in the reworking of mainly Quaternary pebbly substrates from continental
          terraces, pediments, and fluvial deposits. Wave and tidal action at different
          sea level positions resulted in several raised shorelines of Pleistocene and
          Holocene age, which are a typical feature on the coastal plain. These high sea
          level stands are also well represented in the Mampas coastal plains.            In all
          cases, fossil molluscs are present in the sediments; these constitute the best
          tools for correlation and dating (Feruglio, 1950; Rutter et al., 1989).

                It is known that sea level was higher than today at least three times
          during the Quaternary: (1) during the Holocene (maximum sea level about 6,000
          years ago), (2) during the last interglacial (120,000 years ago), and (3) during
          a previous interglacial.     On the Argentine shelf, the Wisconsin shoreline was
          dated in about 18,000 years ago, at depths beyond 100 m (Fray and Ewing, 1963)

                                                    365










                        Centra7 and South America








                                                                                                 URUGUAY
                                                                                           E
                                                                                         AIRES





                                                    .360s.
                                                                                                        WAMOrd,


                                                                          MMACA                    MAR  OCL
                                                                                                     PLATA



                                                      4009Q@            0
                                                                          b"

                                                                    dwft.
                                                                    SM Aft*J0

                                                            PUE     4



                                                    -440s





                                                          MIVAOAVIA
                                                          001fe saw wpr



                                                                 0-
                                                    -480s



                                                          .-I




                                                                             ISLAJ, MAILVIN
                                                       RIO
                                                      qALLEGM
                                                    ...520s




                                                                           0 160 200 3w kM
                                                               IA        OiSTOMOS


                                                    @Oow         66OW       62OW         5L11   1     1.41        5@1*




                       Figure 1. Distribution of predominant geomorphic features along the Argentine
                                                    F
                                                          -Q@
                                                    -7 -























                       coast (Schnack, 1985).

                                                                                     366










                                                                               Schnack, et al.

                Brackish and saltwater marshes are present along the coast, the former
           mainly in the northeastern sector of Buenos Aires Province (Samborombon, Mar
           Chiquita) and also in Bahia Blanca and further southward (Figure 1). The latter
           are predominant in Patagonia, where macrotidal environments prevail. The
           Patagonian coast is predominantly rocky, and cliffy, whereas the Buenos Aires
           (Pampas) coastline alternates between extensive low-lying and cliffy areas.

                Cliffs in the Province of Buenos Aires are generally composed of
           semi -consol i dated, deposits of the Plio-Pleistocene age, reaching their maximum
           altitude (25 m) in the vicinities of Mar del Plata. Only in this city, an old,
           lower Paleozoic quartzite outcrops at the sea.      The Patagonian coast exhibits
           mainly Tertiary sediments, both of marine and continental origin.            Lastly,
           Quaternary, glacially derived sediments outcrop in eastern Tierra del Fuego, and
           Cretaceous marine rocks are the main feature on the Beagle Channel area.

                Although there are several embayments along the whole Argentine coast, Mar
           Chiquita Lagoon inlet is the only one that has the proper attributes of such a
           feature. At a typical microtidal setting, the Mar Chiquita inlet (less than 100
           m wide and less than 3 m deep in the channel axis) shows both seasonal (or
           storm-driven) and historic shifting. As can be seen in Figure 3 (for location
           see Figures 1 and 4), the inlet has a historic trend of northward shifting
           coincidental with the regional net littoral drift. However, engineering works
           have modified the natural adjustment of the inlet.          In the tide-dominated
           Patagonian coast, a few embayments exhibit some features that are common
           attributes of tidal inlets. At San Antonio Bay, in northern Patagonia (Figure
           1), a well-developed flood-ebb delta is active, but no freshwater inflow exists
           in the area.

                Wetlands are distributed all along the Argentine coast. The most typical
           and extensive are those in Bahia Samborombon, where muddy, tidal flats develop
           along 100 km of coastline, at the Salado Basin depression (Figures 1 and 4).
           Also, tidal flats and marshes are present from Bahia Blanca southward. Wetlands
           along the Patagonian coast are not so extensive.      They are more restricted to
           low-lying areas at the several embayments. In all cases, marshes are temperate
           and show the presence of typical vegetation (Spartina, Salicornia). The general
           topography at low-lying areas would allow marsh and vegetation to shift inland
           if a rapid sea level rise occurred.    In some cases, e.g., restricted marshes in
           Patagonia, where a rocky slope borders a narrow coastal plain, migration would
           be limited to a few hundred meters, thus causing marshes to disappear.

                The most prominent estuarine environment is the Rio de la Plata, a water
           body shared by Argentina and Uruguay.      As a continuation of the Parana River
           Delta, the Rio de la Plata has a submerged deltaic front composed of silt-clay,
           but sand banks also occur. The main body is freshwater, but the outer part is
           brackish.   Although no river discharge occurs at present, Bahia Blanca, a
           brackish-water environment with mesotidal action, hosts one of the most important
           harbors. Here, muddy environments and suspended materialls, as well as drifting
           sandwaves and channels, are driven by tidal currents.



                                                   367










   A                                                                 B








                                                                                                   AQ



                                                                                                ;W












   00
                ... . .......... ... .............. ..... .......... . ... ... ..... . . .. .....


                                                                    Figure 2 (A-C)   Coastal features of Argentina.

                                                                    (A) Erosive coastline at the edge of the Pampas plain,
                                                                    looking north.     In the background is Mar Chiquita
                                                                   -Lagoon, where a sandy barrier develops to the north.
                                                                   -The coastal plain has an extremely low topographic
                                                                    gradient.     A sea level     rise makes this region
                                                                    vulnerable, both to beach erosion (dune destruction) and
                                                                    to flooding. Both processes are al.ready occurring to a
                                                             @.Vzan high degree because of human influence.
                                     .@A
                                                                    (B) Low (<2 m) eroding cliffs approximately 20 km north
                                                                    of the Mar del Plata. Beach sediments are scarce. Note
                                                                    the coastal road.

                                                                    (C)   Protected beach (see groins) at Santa Clara, a
                                                                    resort town 18 km north of Mar del Plata.
                          mzll'l




                 . . ..........






     D                                                                E












                                                   77"',

              16
                                                                                                                          I ISM


                                                                                                  41


                                                                                                                                  N@


                                                                                                                                AUA





                                                                                              .......... .


     F                                                              Figure 2 (D-F).

                                                                         Stone defense to rebuild beaches at Mar del Plata
                                                                    (constructed in the early 1980s) . By the 1970s, beaches
                                           I. . . . . . .           in this area were lost.        Many other beaches are
                                                                    protected by groin systems.

                                                                    (E)    15 km south of Mar del Plata center, eroding
                                                                    beaches in an area where sand mining for construction is
                                                                    doen. Note the improverished dune "relicts" resting on
                                                                    an approximately 10 m high cliff which now is being
                                                                    reactivated by dune disappearance.

                                                                    (F)   Part of a tidal salt marsh in Coleta Mabespina
                                                                    (Patagonia). Many similar environments of varying area
                                                                    (usually small in Patagonia and lareger in Buenos Aires
                                                                    Province) are distributed along the Argentine coast.
                                                                    Some may not migrate landward as sea level rises because
                                                                    of topographic (hills) or human barriers, hence, a
                                                                    significant wetland loss may result.













                                          - - - - - - - - - - - - -


                                                      JANUARY 10415
                                         9W  900          X=   20W 0119TER9









                                                              Igo?



                                          MW Soo  0       I=   20M













                                                     cur In JANUARY 1904 OBSTRUCTION
                                                                  In 1904
                                                           ----------- 2W
                                                                   MITERS









                                                       -----------------
                                                                    1900
                                          low Wo  0              2= METERS


             Figure 3. Historic migration of Mar   Chiquita  Lagoon inlet.


                   Several other estuaries are represented  in the coast of Patagonia by the
             river outlets under macrotidal conditions, but few detailed studies have been
             done in relation to water chemistry and dynamics. Bottom sediments are variable,
             with gravels, sands, and muds in different proportions according to the source
             and dynamics.    In this macrotidal setting, most of the fine sediments are
             transported in suspension. Because of the large tidal amplitudes, some of these
             estuaries have extensive uncovered areas during the ebb tide. One such areas is
             the Rio Gallegos outlet, where tidal ranges reach 12 m (Figure 1).

             Cultural and Economic Features

                  According to Brandani and Schnack (1987), human activities along the
             coastal zone of Argentina include urban development and recreation; industry and
             commerce; port activities; fishing, military and naval bases; research; and
             conservation of natural resources. In certain areas, beach sand is mined for
             building purposes.   Other activities include:    mining of coastal gravels and
             shells (from Quaternary deposits), offshore oil exploration and extraction, and
             algae exploitation.   The general features of the major Argentine harbors are
             shown in Table 1.

                                                    370










                                                                                              Schnack, et al.









                  -340S
                                                                                  "P/O


                                                                         R-MOM"





                                                                                         0    Bode
                                                                                   lik       Samborombdn
                                                          12 100            7n 100
                                           A[sin        140
                           LdelM                      NO()
                       L.Ep4cuk




                                          44
                   380S














                                                            Y@
                                                      C)()

                                                                              0     50    100   150 Km
                                                                               I     I           I

                                                                                    SCALE
                  Cart, Mdnica Tomds     6120W                 61OOW

           Figure 4.        General topography of the Province of Buenos Aires.                        Note the
           extremely gentle slope in the Salado Basin depression and in the Rio Colorado-Rio
           Negro region.



                                                             371











                          Centra7 and South America

                                     Table 1. General Characteristics of the Main Harbors in Argentina



                                                                                                                               ANCILLARY                 ECON0141C
                               PORT                        LOCATION              PURPOSE                FACILITIES             FACILITIES              ACTIVITIES


                          Buenos Aires                0 =  34* 341 S         General cargo,         Wharves, berths,           Dockyards,             UwMcaL, textile,
                                                                             bulk and con-          cranes, ware-              shipyards              wtaLLurgical, and
                                                      Q =  58* 231 W         tainer bulk            houses, sheds,                                    food industries
                                                                             terminaL               grain elevators


                          Mar del Plata               0 =  38* 031 S         Fishing port           Wharves, berths,           Dockyards              Fishing inistries,
                                                                             and bulk               cranes, ware-                                     packing houses,
                                                      a =  57* 33, W         terminal               houses, sheds,                                    agricultural and
                                                                                                    grain elevators                                   cattte-raisfng
                                                                                                                                                      activities


                          Quequen and                 0 = 38* 351 S          Grain in bulk          Wharves, berths,           Workshops              Fishing and food
                            Necochea                                         terminal and           grain elevators,           and small              i ndust r i es (meat
                                                      0 = 58* 421 W          fishing port           warehouses                 dockyards              and f I our), agr i -
                                                                                                                                                      cultural and
                                                                                                                                                      cattLe-raising
                                                                                                                                                      activities


                          Bahia Blanca                0 = 38* 47, S          General cargo,         Wharves, berths,           Workshops              Agricultural and
                                                                             grain in bulk          cranes, grain              and sma t t            cattte-raising
                                                      12 = 62* 16, W         terminal, and          elevators, ware-           dockyards              activities
                                                                             fishing port           houses, sheds                                     petrochemical
                                                                                                                                                      industries



                          Puerto Madryn               0 = 42* 46, S          General cargo          Wharves, berths,           Small                  Atunirun factory,
                                                                                                    cranes, ware-              dockyard               fishing indus-
                                                      0 = 65* 021 W                                 houses                                            tries, and sheep-
                                                                                                                                                      raising activities


                          Zone of Comodoro            0 = 45* 52, S          Oil terminal           Wharves, berths,           Workshops              Oil fields, sheep-
                          Rivadavia                                          and fishing            cranes                                            raising activi-
                                                      2 =  67*   291  W      port                                                                     ties, and fishing


                          Puerto Deseado              0 =  47*   45,  S      Fishing port           Wharves, berths,           Workshops              Sheep-raising
                                                                                                    cranes, ware-                                     activities, and
                                                      a =  65*   551  W                             houses                                            food industries


                          Ushuaia                     0 =  54*   49,  S      Fishing port           Wharves, berths            SmalL                  Fishing
                                                                             and general                                       dockyard               activities
                                                      11=  68*   131  W      cargo













                                                                                                372










                                                                           Schnack, et al.

          Demography

               In Argentina, over 41% of the population inhabits the coastal zone.
          Population densities vary along the coast.     A general gradient develops from
          north to south, with the greatest population numbers and densities in the
          nation's capitol, Buenos Aires city, and associated urban centers. The lowest
          population concentrations and variety of activities are found in Patagonia, south
          of the Colorado and Negro Rivers, where a few small urban centers support most
          of the regional population and activities.

               Most of the largest urban centers and 25% of its urban centers with more
          than 5,000 inhabitants are coastal. However, the fact that the federal capital
          (Buenos Aires city), with only 17 km of coastline along the Rio de la Plata,
          contains 10% of the country's total population must be considered. Buenos Aires,
          together with its suburbs (Greater Buenos Aires) is estimated to have ten million
          inhabitants (30% of the national population).

               The continuing historical pattern of population migration to the city
          (averaging a yearly growth rate of 47% between 1869 and 1980, against 13% for the
          national population growth) has been caused by mutually reinforcing factors: the
          Port of Buenos Aires handling 90% of the total waterborne transit and commerce
          of the country; the siting around the city of many of the nation's industrial and
          productive activities; and the concentration of a strongly centralized federal
          government.

               The Province of Buenos Aires, with more than 1,500 km of coastline and
          nearly 12 million people (40% of the national population) is by far the most
          important coastal province (state) of Argentina. The average density is 35.3
          people/km' and over 90% of the population lives in urban centers, the largest of
          which are all coastal (Figure 5): La Plata with 460,000 people, followed by Mar
          del Plata with 410,000 people, and Bahia Blanca with over 220,000 inhabitants.
          Rural areas are dominant along most of the coastline. It is here -- not the
          cities -- where the topography is vulnerable to major inundation from sea level
          rise, as can be observed in the Salado Basin depression with extremely low
          topographic gradients (Figure 4).

               The Patagonian region varies in population distribution according to the
          specific province.  In Rio Negro Province, only 12.5% of the population live in
          coastal centers. This is due to the strong economic influence of the Rio Negro
          Basin and the city of San Carlos de Bariloche, at the foot of the Andes. Farther
          south, in Chubut, more than 80% of the 263,000 inhabitants live in coastal urban
          centers. Santa Cruz Province, the third largest in Argentina, has only 114,900
          people and its density is correspondingly very low:    only 0.5 people/km'.    The
          National Territory of Tierra del Fuego has only 40,549 inhabitants with 38,515
          people living in just two coastal cities: Rio Grande (21,969) in the north, and
          the capital of Ushuaia in the south (16,546).





                                                 373













                                                                                              URUGUAY
                                     -340                                    BUENOS
                                                                            AIRES

                                                                              LA PLATA





                                     -380                   BAHIA BLANCA                  MAR DEL PLATA



                                                SAN ANTONIO
                                                OESTE



                                                             VIEDMA



                                      420 PUERTO
                                            MADRYN





                                                                                         0    1000-5000


                                                                                         0    5000-20000


                                             COMODORO                                    0    20000 - 100000
                                             RIVADAVIA                                   0    100000 - 500000
                                     -460                                   (j

                                                                                              >500000
                                                    Puerto Deseado





                                             Puerto
                                             San Julian


                                           Puerto
                                     -500 Santa Cruz                     ISLAS MALVINAS

                                           RIO                                                     Ile,
                                           GALLE.GOS                                                    Antarctic
                                                                                                         Peninsula


                                           I



                                                                       0    100 200 3OOkm

                                           1USHUA1
                                     P540                  ISLA DE LOS
                                                            ESTADOS                                             South


                                     700            660          620           580            540           500


                    Figure 5. Population of urban centers on the Argentine coast.
                                           R
                                           G
                                           '0
                                           ALL
                                               EGOS
                                                                         .0



                                                               COO














                                           JUSHUAIA
                                           0
                                     @54
                                                                                                                South
                                                                                                                Pole








                                                                           374










                                                                            Schnack, et al.

         Land Use

              Low-lying coastal lands are mainly rural and are found mostly in the
         Province of Buenos Aires (Salado Basin in the north, and the southern tip of the
         state, from Bahia Blanca to Bahia Anegada).      The Salado Basin coastal plain,
         facing Samborombon Bay, is largely devoted to agriculture (mainly cattle).
         Because this is a flood-exposed area, activities are somewhat restricted.

              The area immediately above the highest tide levels in Bahia Blanca is partly
         occupied by housing developments related to the various industries established
         nearby; much of this area is subsiding. South of Bahia Blanca, the coastal area
         is mainly devoted to agriculture. In the northern, sandy belt of Buenos Aires
         Province (Figure 1), and extending southward to Mar del Plata and Miramar,
         tourism is the main land use.

              At the Salado Basin, the recurrence of historic floods led the Public Works
         authorities to construct drainage canals toward Samborombon Bay at the beginning
         of the 20th century.    However, results have not been optimal, as floods have
         occurred ever since.

              As a general case, the Patagonian coastal lands are mainly devoted to sheep
         raising; a very localized algae farming also takes place.

         Fisheries

              Most Argentine fisheries are export -oriented.        In 1981, the country
         contributed 1.69% of the world exports (Espoz, 1985). Fisheries are mainly found
         in shelf waters.     Fish catches are by far predominant, but molluscs and
         crustaceans are also important resources. Oyster and scallop beds are present
         in shallow waters in northern Patagonia. Crustaceans (e.g., prawn, king crab)
         represent typical catches in Patagonia and Tierra del Fuego.

              Commercial sea-farming is not commonplace along the Argentine coast. Only
         a few oyster and mussel farming projects are being carried out in San Antonio
         Oeste, and crustaceans projects in Mar del Plata and Puerto Madryn.         In all
         cases, they are only at the experimental stage.

              The main fishing activities are centered in the ports of Mar del Plata, with
         most of the fishing fleet and processing installations, and more than 70% of the
         total yearly catch.     Other important harbors are:      Ingeniero White (Bahia
         Blanca), San Antonio Este, San Antonio Oeste, Puerto Madryn (Figure 4).
         Additional small harbors are distributed along the Patagonian coast.


         IMPACTS OF SEA LEVEL RISE

              Considering the variety of environments and the socioeconomic importance of
         certain regions of Argentina, a rapid sea level rise, as predicted for high and
         low scenarios (Hoffman, 1984), would result in major damage to coastal areas in
         low-lying, flood-exposed plains and in open marine beaches and cliffs.

                                                375










              Central and South America

              Beach Erosion

                   Erosion is an ongoing process, even at the present rate of sea level rise
              which' has been estimated for the region as 1.6 mm/y (Lanfredi et al., 1988). The
              coastline between Cabo San Antonio and Mar del Plata is undergoing severe
              erosion, partly due to natural causes (e.g., lack of fluvial sediment input, sea
              level rise) and mainly because beach-sand mining and dune urbanization take place
              without any planning or environmental assessment. Engineering structures have
              been installed to protect the shore, but in many cases they operate locally and
              cause downdrift erosion by trapping the transported sediments. At Mar del Plata
              (Figure 6) several groins and jetties have been installed throughout this
              century.   Also, Mar del Plata harbor certainly influences erosion in the
              downdrift direction (northward in the whole region) by breakwaters at its
              entrance.

                   Since erosion is a typical problem of the sandy shoreline and of the cliff
              exposures of Buenos Aires Province, sea level rise should only exacerbate the
              existing problems. At Mar Chiquita beach (Figures 4 and 7), a shore retreat of
              more than 5 mly has been determined (Schnack, 1985), causing land losses and
              property destruction. This is the highest rate in shoreline retreat established
              for the whole coast of Argentina. Many other localities north of Mar Chiquita
              also show increasing erosion as a consequence of human intervention.

                   In a well-known paper,   Bruun (1962) describes a method for determining
              shoreline retreat produced by sea level rise. He assumes that after a sea level
              rise the beach profile will    simultaneously undergo an upward and a landward
              shift, though retaining its    original shape.    Thus, the final beach profile
              displacement can be considered as the result of two rigid translations:            a
              vertical one and a horizontal one, the latter being the shoreline retreat.

                   For the given scenario (Hoffman, 1984), considering a 0.50-, 1.00-, and
              2.00-m sea level rise to take place in a period of 50 years, a beach profile at
              Punta Medanos (Figure 4) would undergo a retreat of 1.93, 3.86, and 7.73 m/yr,
              respectively. These estimates show the dramatic impacts of predicted, rapid sea
              level rise. Furthermore, human-induced erosion represents a major factor that
              must be considered at least as effective as sea level rise itself.

              Hydrologica] Impacts

                   Although hydrological problems along most of the Argentine coast may be
              foreseen as a direct consequence of sea level rise, the Buenos Aires Province
              shows most clearly the effects of anthropogenic activities due to its high
              population density, despite the fact that this population is concentrated at very
              specific points. These activities are responsible for the shifting or breakdown
              of the natural equilibrium. This is particularly true when dealing with
              groundwater resources, for processes operate at different intensities and time
              scales.   Moreover, as groundwater motion is slow, thus hindering direct
              observation, the consequences arising from management decisions may not be
              noticed for several years, and so the results could be irreversible when
              detected.

                                                     376







                          _-22.6                 21)                                                                                         Schnack, et al.

                                                                                  re ALTO
                                                                                      CAMET

                                                                                                                  1978



                               Z3.4                                                                                 -
                                                                                                          1971,1972
                                                                                                                               LOCATKW MAP
                             23.0
                             z                                        .14.0               110





                                                                                                        -;952 1950-modified in 1980
                                                                  ISO.                           1930-1936

                                                                                        SAN
                                                                                          E      Punta 19lesio
                                                                                                  -4931-1935
                                                                                                  -1924-1926                                     WWII-

                                                                                                   1930-1932
                                                                                                        Punta Piedras
                                                                                                          (Toffedn del ManiO
                                                                                                                1924 -modified In 1981
                                                                                                                 1982
                                                                                                                   Cabo
                                                                   0                                  E
                                                                                                                   Corrientes



                                                                                              no

                                                     ZZ-9



                                                               LAS AVEMOAS                                        1919

                                          L MARTI                 13.1





                                                                                                              -1914



                                     so



                                                                                                 J        Net Littoral
                                                                                                      fED r i ft

                                                                                                                                0932 Groin construction'

                                                                                                                                Contour interval: torn

                                                                                                                               0            1        2krn


                             I. Mdrice L       57 3eW
                  Figure 6. Engineering structures                                  at    Mar    del Plata. Except for                        the    harbor, all
                  the structures have been installed to protect the shore from erosion.

                                                                                           377











              Centra7 and South America












                                                                            Mar ChIquito
                                                                              Lagoon


                     1979

                     1970 .......j



                     1957 -------


                               SOUrN ArLANTIC OCEAN


                                                                                  N



                 0    1Q0 200 WOmeters




              Figure 7. Shore retreat at Mar Chiquita beach. Note the land losses, including
              property.


                   Besides the highly disturbed deltaic area, on which little, if any,
              background information is available, three main coastal environments can be
              considered in the province: cliffed, sandy, and marshy shores. As a result of
              sea level rise, saltwater encroachment can take place, the impacts being mainly
              dependent on the physical coastal setting, climatic variation, and human
              factors.

                   A common feature of the three environments is the lack of sufficient
              available data, with the exception of some urban areas.      This poses serious
              restrictions on the reliability of numerical solutions, for they depend upon both
              the quality and quantity of the input data.

                   In Mar del Plata, located at the easternmost extreme of the Tandilia Sierra,
              the aqui fer consi sts of parti al ly reworked Pl i o-Pl ei stocene 1 oess-1 i ke sediments,
                                     L- UL I
                                qN F







                                                     378










                                                                            Schnack, et al.

         with an average depth of 100 m.    It had undergone over-pumping until the 1960s.
         As a result, seawater intrusion was detected, and nearly all the pumping wells
         located within the city and close to the coast were abandoned. The exploitation
         zone had to be shifted to the north.        This action led to a restoration of
         groundwater tables which had flooded buildings, and has acted as a hydraulic
         barrier preventing a landward migration of the freshwater/saltwater interface.
         Today the situation in the well field can be considered at equilibrium. Hence,
         in Mar del Plata the landward migration of the saltwater front due to sea level
         rise would be negligible when compared with the human-induced migration.

              A different situation can be observed toward the north of Mar Chiquita (a
         small town located about 30 km north of Mar del Plata). A sand dune barrier,
         which extends for more than 150 km and becomes progressively wider northward,
         overlies marine-estuarine sediments of Holocene and Pleistocene age (Fasano et
         al., 1982; Parker, 1980). At the low-lying coastal plain of Samborombon Bay,
         sand dunes are replaced by shelly beach ridges (Sala et al., 1977). Both sand
         dunes and shelly ridges are the only available freshwater storage bodies. These
         storage bodies can be idealized as if they were an elongated island surrounded
         by seawater on the east and brackish-to-salty continental waters on the west.
         Because of this, the sandy barrier could be largely influenced by a eustatic sea
         level rise.    According to the erosion rate measurements, e.g., 5 mly at Mar
         Chiquita (Schnack, 1985) (Figure 6), the horizontal component exceeds in orders
         of magnitude the rise in sea level (1.6 mm/y) in the vulnerable sandy coastline.
         The landward migration of the interface would be largely controlled by the beach
         retreat. Changes in altitude of the base level play a minor role. In fact, as
         stated by Urish and Ozbilgin (1989), the groundwater/free seawater interface is
         a highly dynamic boundary. On sandy sloping beaches, tidal fluctuations and wave
         run-up cause an effective mean sea level generally higher than free-water mean
         sea level.

              Kana et al. (1984) summarizes the different opinions about the effect of sea
         level rise on the position of the freshwater/saltwater interface in a water table
         aquifer.   Some state that the whole system would shift upward and landward
         proportionally to sea level rise and shoreline retreat, respectively.        Others
         consider that freshwater rise would not follow sea level rise at the same rate,
         but would be some fraction of it as a consequence of decreasing recharge and
         increasing discharge.

              Under nondeveloped conditions, the lens-shaped groundwater reservoir can be
         regarded as being in dynamic equilibrium by direct recharge from precipitation
         and discharge to the sea.     It seems reasonable that a sea level rise of the
         magnitude considered here is sufficiently slow to allow groundwater to reach a
         new equilibrium position.

              Floods are very dramatic on the Rio de la Plata shores, with the highest
         population density. Here the water level rose 4.75 m over datum in 1940 and 3.85
         m i n 1958.    In the latter case, more than a half million inhabitants were
         affected by property losses and other damages.



                                                 379










              Central and South America

                   The marshy areas of Buenos Aires Province extend mainly south of Bahia
              Blanca and also border Samborombon Bay. In these environments, erosion does not
              seem to be a dominant process. Due to the extremely gentle topographic gradient,
              minor positive variation in sea level causes the flooding of extensive areas with
              consequent land loss (Figure 3).       This would allow an inland movement of
              seawater, resulting in its intrusion into the groundwater system. Additional
              effects, such as longer-lasting floods are linked to higher water tables, which
              inhibit the infiltration process during precipitation. From the point of view
              of groundwater as a resource, these effects would not pose a severe risk because
              brackish-to-salt water dominates.

              Other Impagts

                   A rapid sea level rise would result in several disturbances of various
              degrees of importance, depending on the urban development, industries, general
              resources, and installations.

                   Impact on harbors (Table 1), in any of the predicted scenarios, would be
              high in Buenos Aires and Bahia Blanca because of the flat, low-lying terrain of
              the surrounding areas where very important economic activities take place. At
              Mar del Plata, Quequen, Puerto Madryn, and Comodoro Rivadavia the impact would
              be only moderate and the affected areas would be those next to the shoreline.
              Landscape damage and pollution effects can be predicted. At Puerto Deseado and
              Ushuaia the impact would be low, mainly restricted to the port facilities and
              their adjacent areas.

                   Wetlands would also be affected, either by migration and recolonization or
              by disappearance when migration is restricted by highlands or hard substrates.
              As we consider a rapid sea level rise, it is likely that inland migration of
              wetlands would keep pace in vertical growth relative to the rate of sea level
              rise. Under these conditions, a rough estimate suggests an average loss of 50%
              of the wetlands area.

                   The inland transportation of pollutants would also be a direct effect of a
              rising sea level.   This would be particularly important in heavily populated,
              industrial, and harbor areas (Buenos Aires, Mar del Plata, Bahia Blanca), as well
              as in Patagonia, where oil spills maybe transported inland (Comodoro Rivadavia).
              Although they are not yet in existence, sea-farming establishments may also be
              affected to some extent.



              RESPONSES

              Institutional Background

                   Government and legal instruments for coastal planning and protection are
              dispersed and no specific framework for coasts is available.       A document on
              national priorities for marine and coastal research (SECYT, 1983) identified the
              lack of properly trained personnel and of coordination between research and
              management activities as significant issues.

                                                     380










                                                                            Schnack, et al.

              At present, coastal issues show several problems related to organizational
         levels: lack of coordination and overlapping among public agencies; confusing
         and contradictory laws and regulations, and insufficient resources for adequate
         coastal zone management.

              The conflicts between pollution, recreation, and coastal protection, for
         instance, are significant in the larger summer resorts of Buenos Aires Province,
         such as Mar del Plata. Coastal erosion has led to the construction of a variety
         of costly defenses in order to prevent the disappearance of beach resources and
         to reverse the destructive tendencies caused by sand-trapping devices (mainly
         groins).    These defenses produce the desired effect in one place, i.e.,
         accumulation of sand, but at the expense of other beaches, which end up being
         heavily eroded, as is the case between Mar Chiquita and Miramar (Figures 4 and
         6). These conflicting activities in Buenos Aires Province have an institutional
         background.    Construction of coastal defenses is the responsibility of a
         Directorate of the Provincial Ministry of Public Works, and a separate
         Directorate of the same Ministry grants permits for sand extraction from beaches
         and dunes, an erosion-triggering activity.     No integrated planning procedures
         exist among the Directorates within the Ministry. Moreover, while tourist use
         and exploitation of the shore are the domain of municipal governments, port
         activities (a major source of pollution and erosion in Buenos Aires and Mar del
         Plata, among others) are under federal government jurisdiction.

              Table 2 presents a summary of governmental units related to functional or
         sectorial aspects of marine and coastal zone management. The hierarchical level
         for each government unit (whether national or provincial) is shown in Roman
         numerals (I  is the highest and corresponds to the chief executive's office,
         whether the nation's president or the governors).       When some sector is al so
         represented   within the government structures of coastal provinces, its
         hierarchical level is    indicated.  Only names of the federal institutions are
         listed under  the "nation" heading. Provinces are, from north to south: BA ,
         Buenos Aires; RN, Rio Negro; Ch, Chubut; SC, Santa Cruz, and TF, Tierra del
         Fuego.

              Table 2 lists only those sectors currently related to coastal zones for
         which some governmental unit exists.      For farming, ranching, education, and
         forestry, no special orientation to coasts is found within governmental
         structures.   For the last sector, this is understandable since the Argentine
         shoreline is essentially a treeless corridor (Brandani and Schnack, 1987).
         However, farming practices affect estuaries and coastal wetlands through the
         concentration of runoff products, agrochemicals, and sediments.

              Defense and production are concentrated in units of relatively high
         hierarchical level within the federal government.       Development and wildlife
         management have a higher priority in the provinces than at the national level.
         Development is mostly industrial in nature, and ecological management emphasizes
         the exploitation of specific renewable resources for production or consumption,
         rather than the conservation of integrated environmental systems.



                                                 381










                  Central and South America

                  Table 2. Argentine Governmental Organizations With Primary Policy Authority
                              for Marine and Coastal Resources


                                                                                              Provinces
                                                                          HierarchicaL
                         Sector                     Name                     Level      BA        RN       Ch     Sc      TF


                  Defense operations   Armada                                           ne        ne       ne     ne      ne
                  Foreign policy       Ministerio de ReLaciones Exteriores;    11       ne        ne       ne     ne      ne
                  Customs              Direccion de Aduanas                    IV       ne        ne       ne     ne      ne
                  Port ackninistra-
                   tion                Ackninistracion General de Puertos      IV       ne        ne       ne     ne      ne
                  Port activities      Capitania General de Puertos              V      ne        ne       ne     ne      ne
                  Port maintenance     Direccion de Construcciones
                           b             Portuarias y Vias NavegabLes            V      ne        ne       ne     IV      ne
                  Navigation           Prefectura Naval                        IV       ne        ne       ne     ne      ne
                  Fisheries control    Direccion de Pesca                     III       III       III      IV     IV      IV
                  Coastal tourismd     Subsecretaria de Turismo                IV       III       III      IV     III     III
                  Research (civil-
                   ian)c               Conselo Investigaciones Cientificas
                                         y Tecnicas             d              IV       IVe       IVe      nee    IV      nee
                                       Universidades NacionaLes'               IV                          Ive    ne      ne
                                       Instituto de Investigaciones
                                         Pesqueras                             IV       ne        ne       ne     ne      ne
                                       Direccion del Antartico                 IV       ne        ne       ne     ne      ne
                  Research (mili-      Direccion de Investigacion y
                   tary)c                DesarroLLo                           III       ne        ne       ne     ne      ne
                                       Servicio Hidrografia Naval             III       ne        ne       ne     ne      ne
                  Shore protection                                             ne       III       III      IV     III     ne
                  Wildlife manage-
                   ment                Direccion de Fauna SiLvestre            VI       IV        III      III    III     IV
                  Parks--conserva-
                   tion                                                        ne       IV        III      IV     IV      IV
                  Zoning--PolLu-
                   tion controLa       Direccion de Ordenamiento AmbientaL       V      IIIt      III      IV     IV      IV
                  Waterworks           obras Sanitarias de La Nacion           IV       IV,       ne       ne     ne      ne
                  oil and gas ab
                   development         Secretaria de Energia                  III       ne        ne       ne     ne      ne
                                       Yacimientos PetroLiferos Fiscates       IV       ne        ne       ne     ne      ne
                                       Gas del Estado                          IV       ne        ne       ne     ne      ne
                  Mining               Secretaria de Mineria                  III       III       III      IV     IV      IV
                  Industrial
                   development         Secretaria de DesarroLLo Regional       IV       IV        IV       III    III     III

                  dMore than one governmentat unit deals with sector.
                  bIn addition to several governmental units, national companies participate in sector.
                  cSeparate units are dedicated to sector with different objectives.
                  dUniversity research is actually carried out by Departments or Institutes, with Lower hierarchy than
                  indicated.
                  eLocated in coastal provinces where they research according to regional needs.
                  fSome coastal cities may have a company providing primary services.
                  ne = Non existing.
                  Source: Brandani and Schnack (1987).


                        There is no specific legal framework for coastal issues at either the
                  national or provincial level in Argentina.                     Some legislation related to other
                  aspects (e.g., control of pollution by naval vessels, fisheries, etc.) considers
                  a few coastal aspects. Also, a number of provincial decrees (e.g., to prevent
                  sand mining on beaches) and municipal resolutions provide some approaches to
                  solving coastal problems from a legal point of view.


                                                                      382






                                                                                 Schnack, et al.

          Expected Responses to a Sea Level Rise

               If we consider the preceding paragraphs, it is clear that sea level rise is
          not an issue at the institutional or the general public levels. Only a small
          part of the scientific population regards this as an important problem.                In
          addition, there is insufficient evidence, from an observational basis, to really
          evaluate if a true sea level rise is occurring throughout the entire coastline.
          Most of the erosion and environmental disturbances are due to human intervention
          on coastal areas. Moreover, it must be considered that other hazards, such as
          inland flooding, earthquakes, landslides, and other phenomena, seem to have more
          dramatic effects and general concern among the public and institutions because
          they tend to affect the economy more noticeably.

               However, if an integrated, environmental policy is established, the coastal
          issue may become progressively more important.          Coastal protection would be
          seriously considered and sea level rise properly regarded as an important factor.

               Based upon scientific evidence, future efforts should result in the adoption
          of legal and administrative procedures for proper use and protection of the
          coastal zone.



          BIBLIOGRAPHY

          Brandani, A.A. and E.J. Schnack.          1987.    The Coastal Zone of Argentina:
          Environmental, Governmental and Institutional Features.          Journal of Shoreline
          Management 3:191-214.

          Bruun, P.     1962.   Sea Level Rise as a Cause of Shore erosion.           Journal of
          Waterways and Harbors Div. 88:117-130.

          Caviglia,  F.J. 1988. Intrusion salina en el Rio de la Plata. I.T.B.A., Buenos
          Aires, 38  p.

          Espoz Espoz, M. 1985. Introduccion a la Pesca Argentina. Fundacion Atlantica,
          Mar del Plata, 336 p.

          Fasano, J.L., Hernandez, M.A., Isla, F.I. and E.J. Schnack.            1982.    Aspectos
          evolutivos y ambientales de la laguna Mar Chiquita, Provincia de Buenos Aires,
          Argentina. Oceanologica Acta No. Esp., 285-292.

          Feruglio, F. 1950. Descripcion geologica de la Patagonia. Y.P.F.

          Fray, C. and M. Ewing.        1963.   Pleistocene sedimentation and fauna of the
          Argentine Shelf. In: Wisconsin Sea Level as Indicated in Argentine Continental
          Shelf Sediments.. Proceedings of the Academy of Natural Sciences of Philadelphia.
          115:113-126.

          Hoffman, J.S. 1984. Estimates of future sea level rise. In: Greenhouse Effect
          and Sea Level Rise. M. Barth & J. Titus, eds. Van Nostrand Reinhold Co., New
          York. 79-103.




                                                    383






              Central and South America

              Kana, T.W., Michel, J., Hayes, M.O. and J.R. Jensen. 1984. The physical impact
              of sea level rise in the area of Charleston, South Carolina. In: Greenhouse
              Effect and Sea Level Rise. Van Nostrand Reinhold Co., New York, 105-150.

              Lanfredi, N.W., D'Onofrio, E.E. and C.A. Mazio. 1988. Variations of the mean
              sea level in the southwest Atlantic Ocean.       Continental Shelf Research.
              8(11):1211-1220.

              Parker, G. 1980 Estratigrafia y evolucion morfologica,durante el Holoceno en
              Punta Medanos (Planicie costera y plataforma interior).   Provincia de Buenos
              Aires. Simp. sobre Problemas Geologicos del Litoral Atlantico Bonaerense, Com.
              de Inv. Cient. de la Provincia de Buenos Aires. Resumenes (La Plata). 205-224.

              Rutter, N., Schnack, E., del Rio, J., Fasano, J. Isla, F. and U. Radtke. 1989.
              Correlation and dating of quaternary littoral zones along the Patagonian Coast,
              Argentina. Quaternary Science Reviews 8:213-234.

              Sala, J.M., Gonzalez, N. and M. Hernandez.     1977.   Efectos de la barrera
              hidraulica natural en las aguas subterraneas del litoral de Bahia Samborombon.
              Obra del Centenario del Museo de La Plata. t. IV, Geologia. La Plata, 153-166.

              Schnack, E.J. 1985. Argentina. In: The World'    s Coastlines. E. Bird and M.
              Schwartz, eds. Van Nostrand Reinhold Co., New York, 69-78.

              SECYT (Secretaria de Ciencia y Tecnica).   1983.  Programa de investigacion y
              desarrollo en Pecursos Marinos Costerns y lagunares de la Provincia de Buenos
              Aires. Buenos Aires. 30 p.

              Urish, D.W. and M.M. Ozbilgin.     1989.   The coastal groundwater boundary.
              Groundwater 27(3):310-315.























                                                   384











            REGIONAL IMPLICATIONS OF RELATIVE SEA LEVEL RISE
                     AND GLOBAL CLIMATE CHANGE ALONG THE
                          MARINE BOUNDARIES OF VENEZUELA


                                    RUBEN APARICIO-CASTRO
                                       JULIAN CASTANEDA
                           Instituto Oceanografico de Venezuela
                                    Universidad de Oriente
                                   Cumana-Sucre, Venezuela

                                         MARTHA PERDOMO
                             Ministerio del Ambiente y de los
                               Recursos Naturales Renovables
                                   Caracas 1010, Venezuela






         ABSTRACT

              Sea level data on the marine boundaries of Venezuela have been analyzed
         using several tidal-gauge stations with continuous records ranging from 21 to 36
         years. The rates of change in sea level have been highly variable. All of the
         time series examined, except two, show a tendency toward increase in sea level,
         with values ranging from 3.26 mm/year in Maracaibo Lake (an area of remarkable
         petroleum and groundwater extraction during the last 50 years) to 0.91 mm/year
         at Amuay. The easternmost tidal-gauge stations, located on Carupano and Puerto
         Hierro, exhibit a lowering trend, which can be explained in terms of tectonically
         induced uplift of this regional land mass due to its proximity to the boundary
         between the Caribbean and the South American tectonic plates.
              In an attempt to determine the Venezuelan coastal zone's vulnerability, this
         paper indicates the lowland areas likely to be affected by this phenomenon and
         discuss the resulting environmental, social, economical, and geopolitical
         implications of these changes.     Among other factors associated with global
         climate change, the frequent occurrence of tropical storms and hurricanes in the
         Caribbean Basin, and the changes in their track and destructive potential, emerge
         as some of the most negative effects influencing the Venezuelan coastal zone in
         the near future.





                                                385










               Central and South America

               INTRODUCTION

                     Global warming could disrupt environmental conditions and political
               institutions throughout the world.         In the recent past, the threat of a
               greenhouse warming has been studied by the United Nations Environment Programme
               (UNEP) through its Regional Seas Action Plans, in conjunction with the World
               Meteorological Organization (WMO) and the Intergovernmental Oceanographic
               Commission of UNESCO.

                     A 1988 UNEP study of the Wider Caribbean Region (including the Caribbean
               Sea, the Gulf of Mexico, and the Florida-Bahamas area of the Atlantic Ocean)
               emphasized the marine and coastal environment and addressed the implications of
               climate changes in that region.      That research served as a starting point to
               initiate local scientific concern about anthropogenically induced global climate
               changes in Venezuela.

                     This paper characterizes the Venezuelan coastal zone and summarizes its main
               geodynamic and geomorphological features, its typical ecosystems, and its
               socioeconomic importance.      It presents some evidence of local variations in
               climate conditions along the marine boundaries of Venezuela, examines the local
               signal of relative mean sea level variability from tidal-gauge records, and
               di scusses the resul tant envi ronmental , soci al , geopol i ti cal , 1 egal , and economi c
               implications of the regional pattern of alterations in climate conditions.
               Finally, it presents, for the consideration of Venezuelan authorities, a set of
               recommendations of domestic importance toward implementing an effective national
               response policy.


               NATURAL CHARACTERISTICS OF THE VENEZUELAN COASTAL ZONE

                     Venezuela's coastline constitutes approximately 52% of the southern coastal
               boundary of the Caribbean Sea and an appreciable portion of shoreline on the
               Atlantic Ocean. Many types of coastal environmental stages are exposed along the
               approximately 4,000 kilometers of the Venezuelan shoreline: sandy marshland,
               beaches, cliffs, deltaic plans, coastal lagoons, barrier islands, estuaries, and
               bays.   These environments are distributed on both Venezuela's Caribbean Sea
               boundary (2,720 kilometers) and its Atlantic Ocean border (1,300 kilometers).
               In addition, its 200 nautical miles of Exclusive Economic Zone (EEZ), with an
               area of 630,000 square kilometers, comprises around 300 islands, islets, and
               keys.

                     While sandy shorelines and beaches appear frequently along the Caribbean Sea
               border, sandy marshlands are confined to the Peninsula of the Paraguana at the
               western section. The presence of cliffed coastal portions is clearly evident.
               Deltaic zones are few, with the Orinoco Delta, on the Atlantic margin, emerging
               as the most extensive one, occupying 88,000 square kilometers in its drainage
               basin and 22,500 square kilometers in its receiving basin. The Unare Delta, in
               the central section of the Caribbean boundary, with a drainage basin of 22,300
               square kilometers and only 28 square kilometers of area in its receiving basin,
               consists of two big coastal lagoons (Unare and Piritu) separated from the sea by

                                                        386









                                                                   Aparicio-Castro, et al.

         very low-lying sandy barriers and partly protected by a mangrove forest of
         limited extent.

              Any general attempt to summarize a broad geodynamic characterization of the
         Venezuelan coastal area should consider the following features:

              4    It lies on a very tectonically active zone.          Located along the
                   country's easternmost coastal section is a significant proportion of
                   present-day global seismicity (see Figure 1).

              4    The local surface wind field presents a remarkable persistency in its
                   mean directional distribution, reflecting the regional predominance of
                   easterly winds and implying favorable conditions for coastal upwelling
                   throughout the whole year. However, with regard to the wind field's
                   strength,  a   notable   westward   intensification   is  evident,    and
                   consequently, the local rate of evaporation on the western Venezuelan
                   coastline is enhanced.

              0    The seasonal fluctuation of the Intertropical Convergence Zone is
                   usually thought to be the most important factor controlling the local
                   rainfall pattern.

              6    The local tidal regime presents a microtidal mean range and gradual
                   westward increase of the form number, implying the occurrence of mixed,
                   mainly semidiurnal, tides at the easternmost section; mixed, mainly
                   diurnal tides at the central part; and diurnal tides at the westernmost
                   portion.

              0    Tropical cyclone activity has not been significant in the past.
                   Specifically, up to 1972, only three tropical storms occurring over the
                   southern coastal boundary of the Caribbean Sea had reached the category
                   of "hurricane" during the entire century.

              0    The coastline along the marine boundaries of Venezuela shows clear
                   signs of geomorphological changes.     Table 1 shows the area of the
                   Venezuelan shoreline where coastline changes have been well documented
                   (see, for example, Bird, 1985).


         VAST RESOURCES OF THE VENEZUELAN COASTAL ZONE

              The socioeconomic and ecological importance of the Venezuelan coastal area
         is well established.

         Oil Resources

              About 50% of the total population of Venezuela, estimated to be 20 million
         people for 1990, resides in the coastal zone. Additionally, the oil industry,
         which is the primary resource for national income, bases its operations on
         structures located mainly on the coastal margin. In particular, these structures

                                                387








              Central and South America



                           85*W       80*W        75*W       70*W       65*W        60*W



                                                 t4                                           25*N



                                CO


            20*N                                                                              204





                                                                                a GUADALOUPE


           15* N                      CARIBBEAN SEA                                           15*N
                         r.j*                                           50QOOO Km  0


            101H                                        i/*                         TRINIDAD  104

                                                                 VENEZUELA


                                                               N






                           85*W        801W       75*W       70*W       65 *w       60 *W


              Figure 1. Venezuelan marine territory   in the Caribbean Sea.


              are located on the westernmost portion. They include the estuarine system formed
              by the Lake of Maracaibo, the connecting waterways of El Tablazo Bay, and the
              Maracaibo Straits. Expansion of the national oil industry implies, in addition,
              the establishment of macro-facilities on the easternmost section of the
              Venezuelan coastal margin (Araya and Paria Peninsulas) during the next five
              years.

              Fishery Resources

                  The entire coastal zone of Venezuela possesses valuable fishery resources
              that have the potential of continuous production if they are efficiently used.
              The wind-induced coastal upwelling observed in the area is the key physical
              mechanism responsible for the high biological production characterizing local
                             es.
              fishery activiti

                  The northeastern section of the country has been an important fishing area
              for a wide variety of pelagic and demersal species. Specifically, the Gulf of
              Cariaco, the western coast of the Araya Peninsula, and the southern and

                                                    388









                                                                    Aparicio-Castro, et al.

                               Table 1. Venezuelan Coastline Changes


         1.    Orinoco Delta                    Progradational long-term trend

         2.    Gulf of Paria                    Encroaching of swampy shores at the north

         3.    Western shore  of the            Sea gaining
                 Araya Peninsula

         4.    Coastal boundary of the          Erosion
                 Unare Bay

         5.    Tucacas                          Beach erosion

         6.    Eastern shore of the             Extensive beach erosion
                 Medanus Isthmus

         7.    Falcon Province on the           Active cliffing
                 Paraguana Peninsula

         8.    Mitare Delta                     Progradation

         9.    Southern side of the             Active cliffing
                 Guajira Peninsula

         10.   Western coast of the             General recession os sandy coastline
                 Gulf of Venezuela

         11.   Swampy southern shore of         Progradation
                 the landlocked embayment
                 of Lake Maracaibo




                                            CARIBBEAN SEA


              10           T
                      6


                                                         C1          3

                                                           4


                                           VENEZUELA




                                                 389







              Centra7 and South America

              northeastern coasts of the Island of Marg4rita are zones of above-average sardine
              fishing (Sardinella anchovia). The northwestern coastal portion, including the
              Maracaibo estuarine system and the Gulf of Venezuela, has been the source of the
              large increase in the total Venezuelan production of shrimp. Additionally, the
              central and eastern   areas of the Venezuelan coast present a set of marine
              physical conditions   favorable to surface catches of Atlantic skipjack and
              yellowfin tuna. This has been extremely beneficial to the local economy during
              the last five years.

              Marine Ecosystems

                   Some of-the most productive and biologically complex marine ecosystems in
              the world, such as coral reefs, seagrass beds, and mangrove forests, are present
              along the Venezuelan coastal zone (see Figure 2).

                   Coral reefs, consisting of the consolidated skeletons of corals, accumulate
              rapidly in geological time and constitute the basis of many coastal fisheries.
              They provide food, shelter, and nursery areas for commercially valuable fishes
              and crustacean species. In addition, the reef forms breakwaters, which protect
              harbors and bays, and limit coastal erosion.

                   Mangrove forests, a coastal feature of tropical regions, develop in low-
              lying coastal areas where freshwater is supplied by rivers or terrestrial runoff.
              The forests provide, through their prop roots, a surface to which marine
              organisms can become attached. This, in turn, reduces tidal and wave energy.

              150   720   710   700   690   680   670   660   650   640   63*   620   610     150


              140-                            CARIBBEAN SEA                                   140


              130 -                                                                           130



              12* -                                                                           120



              110 -                                                                           110



              100                                                                             100



              90                                                                              90



              80                                                                              80
                     720   71*   700   690   68'   670   65P   W     640   630   62*   610
              Figure 2.  Spatial distribution of mangrove forests (n) and seagrass beds
              along Venezuelan marine boundaries.

                                                     390










                                                                   Aparicio-Castro, et al.

               Seagrass beds, which cover the bottoms of coastal bays, provide sediment
          retention and stabilization processes that are very important for adjacent coral
          reefs. The beds prevent the abrasion and burial of the reefs during conditions
          involving high wave energy. Additionally, seagrasses serve as nurseries for the
          Juvenile populations of commercially important species, including fishes and
          invertebrates (lobsters, conches, bivalves, etc.).


          EVIDENCE OF CLINATE CHANGE ALONG THE COASTAL AREA OF VENEZUELA

               Evidence of long-term climate variations along the coastal margin of
          Venezuela in recent decades has been reported by Aparicio (1988).        The main
          qualitative findings of that study, based on data records no older than 35 years,
          are summarized in Table 2.

               The pattern of variability in relative mean sea level along the Venezuelan
          marine boundary, extracted from tidal -gauge stations, shows strong local tectonic
          signals at the easternmost zone (see Table 3). In fact, signals given by sensors
          located on Puerto Hierro and Carupano reflect a clearly tectonically induced
          uplift of this local land mass, which can be explained in terms of the proximity
          of this zone to the boundary between the Caribbean and the South American
          tectonic plates. The global signals of sea level rise seem to be present along
          the central part of the Venezuelan coastal margin, such as is evidenced by
          examination of the records at Cumana and La Guaira. Another strong local signal
          can be seen by examining sea level data from the Maracaibo tidal-gauge station.
          A clearly anthropogenically induced local subsidence characterizes that signal,
          due to petroleum/groundwater extraction activities in the area during the last
          50 years.


          IMPACTS OF GLOBAL CLIMATE CHANGE

               The most obvious negative effect is submersion due to mean sea level rise
          and loss of low-lying lands. The areas that seem to be particularly vulnerable


          Table 2. Long-Term Temporal Variability of Climatological and Surface
                    Oceanographical Conditions Along the Marine Margin of Venezuela'


          Parameters                                  Long-term linear trend


          Air Temperature                             Increase
          Evaporation                                 Increase
          Precipitation                               No significant change
          Zonal Wind Stress                           Decrease
          Sea Surface Salinity                        Increase

          'Based on data collected on land site coastal weather stations.

                                                 391












                Central and South America

                Table 3. Relative mean Sea Level Variability Along the Venezuelan Coast Long-
                           Term Linear Trend

                                                                              Linear       Standard
                Station                                         Record       trend         deviation
                Code      Location       Lat.        Long.      length      (mm/year)      (mm/year)


                   I  Puerto Hierro     10*37'N   62*05'W    1955-1963          -4.36          3.26

                   2  Carupano          10040'N   63015'W    1967-1987          -2.12          1.07

                   3  Cumana            10028'N   64012'W    1953-1976          1.92           0.59

                   4  La Guaira         10028'N   66056'W    1953-1989          2.24           0.41

                   5  Amuay             11045'N   70013'W    1953-1985          0.91           0.61

                   6  Maracaibo         10041'N   71035'W    1964-1989          3.26           0.61




                                                  CARIBBEAN SEA



                             5


                   6                                 4




                                                    VENEZUELA






                are the most external portion of the Orinoco Delta, the easternmost area of the
                Peninsula of Paria, and the region enclosing the small Unare Delta and the Unare
                and Piritu lagoons, which constitutes, perhaps, the Venezuelan coastal area that
                may have received the most negative influences from human activities in recent
                years. Specifically, this region is experiencing (1) erosion, mainly induced by
                deforestation and industrial and urban development, and (2) salinization of the
                Piritu Lagoon, which is due, in part, to restriction of the freshwater supply
                (gradual damming of the Unare River) and to uncontrolled use of chemicals in
                certain agricultural processes.


                                                          392








                                                                   Aparicio-Castro, et a7.

               Saline intrusion in local groundwater resources is another negative effect
          produced by sea level rise that will affect the Venezuelan coastal area --
          specifically, those coastal aquifers located in the Peninsula of Paraguana
          region, which, in turn, have been under indiscriminate exploitation during the
          last 25 years. Surely, a sea level rise will worsen the actual water quality of
          these aquifers, with negative consequences to local agricultural resources
          (Alvarado, personal communication, 1989).

               Coastal erosion of beaches will have a tremendous impact on national efforts
          to develop the tourism industry. The most vulnerable areas seem to be Tucacas,
          on the Falcon Province; beaches on the Mochima National Park, which is located
          in the country's eastern coastal region; and Margarita Island, which has very
          high economic activity along its margin.

               A particular case to be considered concerns the geopolitical implications
          for Venezuela derived from the reduction in area affecting Aves Island, which is
          the only outcrop of the Aves Ridge above sea level into the Venezuelan Basin of
          the Caribbean Sea. This island constitutes a large portion (about 135,000 square
          kilometers) of Venezuelan marine territory (see Figure 3).       A comparison of
          geological surveys of Aves Island, which is only 3.7 meters above sea level at
          its highest point, reveals that the island has been progressively reduced in size
          during the last 30 years. Probably the factors responsible for this reduction
          are mainly local erosional processes and the subsidence rate of the Aves Ridge
          (Schubert and Laredo, 1984). Sea level rise in the Caribbean Sea, which has been
          actually estimated to average approximately 4 mm/year (Maul and Hanson, 1988),
          could exacerbate the present-day erosional instability of Aves Island with
          unpredictable consequences for Venezuela from a legal point of view.








                           CARIBBEAN SEA


                                                                       AV ESISLAND

                                                    "VZLA


                                                                   VENEZUELA





                                                               Waco
                                                                                        VZLA/
                                                              VENEZUELA

                                                                                        %)

          Figure 3. Aves Island generates approximately 135,000 Ke of marine territory
          for Venezuela.

                                                 393











              Central and South America

                   Displacement of traditional fishing, sites, even on a relatively small
              spatial scale, could emerge as a consequence of the alteration of the
              thermohaline structure of the coastal marine surface layer along the Venezuelan
              shoreline. This could harm local artisanal fisheries, with a negative effect on
              domestic economies, especially those located along the eastern section of the
              country.

                   Sea surface temperature (SST) in the Atlantic Ocean/Caribbean Basin is
              supposed to increase in response to global warming of the lower atmosphere. As
              a result, this part of the world would present, in the near future, better
              thermal conditions for the genesis of hurricanes and tropical storms. A recent
              work (Emanuel, 1987) reports that an increase in SST of 1.5*C would enhance the
              potential maximum hurricane wind by about 8%.    It also has been reported that
              more frequent intensification of tropical systems to tropical storms could be
              expected (Shapiro, 1988).    As has been mentioned previously, the Venezuelan
              marine margin has been out of the standard track of hurricanes during this
              century. However, two recent facts related to cyclonic activity in the Caribbean
              region deserve special consideration: (1) the strongest recorded hurricane of
              this century, Hurricane Gilbert, beat the Caribbean Sea in 1988, and (2) a
              hurricane (Hurricane Joan) hit the Venezuelan coastal territory for the first
              time during this century in 1989 (see Figure 4).      Changes induced by global
              climate variations in the location of the geographical area favorable to the
              genesis of hurricanes and tropical storms on the tropical Atlantic Ocean are,
              then, of crucial importance for Venezuela.


              RESPONSE POLICY

                   Despite the efforts of the local scientific community, the need to adopt
              strategies to manage the impact of global climate changes on the Venezuelan
              coastal geography has not yet been clearly understood by national authorities.
              This seems to be a logical consequence of the considerable uncertainty
              characterizing technical reports regarding the magnitude of future alterations
              of global lower atmospheric and surface marine conditions typifying regional
              climate.

                   Actually, Venezuelan scientists involved in this problem face the task of
              motivating official decision-making agencies. In this sense, the international
              pressure placed on the Venezuelan government, which has been recently invited to
              subscribe to global agreements related to the matter (The Montreal Protocol, The
              Hague Declaration), has been considerably beneficial.

                   Arrangements are being made to form a local technical committee that would
              have as its primary task the preparation of a government response to the
              implications of global climate changes on Venezuela's geography. In this sense,
              local official agencies dealing with environmental policy, and Venezuelan
              scientists related to the earth sciences, are being encouraged to initiate a work
              platform on the basis of collective action and shared efforts.



                                                    394









                                                                  Aparicio-Castro, et a7.

                                                                                        30'


                                \HUGO (1989)                        \HELENA 1988
                                                      GABRIELLE                         25*
                                                       (1989)



                                                                                        20'





                                                     IN.
                            'CARIBBEAN SEA    /98                                       15'


                ,,,,J OAN (1988)

                                                                                         10,


                                         vENEZUELA


                                                                      ATLANTIC OCEAN     5.


           6                                                          a        1
           85:     810.     75*     70,     65*      60*     55*      50*     45*     40*

         Figure 4.    Track of the most destructive     hurricanes affecting the greater
         Caribbean  Sea region during 1988 and 1989.


               This committee will be sponsored by the Ministerio del Ambiente y de los
         Recursos Naturales Renovable (MARNR), which is the national agency responsible
         for environmental policy in Venezuela. The following specific objectives are to
         be addressed by that committee in the immediate future:

               4   Coordinate national activities related to research and monitoring of
                   meteorological and oceanographic surface conditions among all regional
                   institutions charged with the responsibility of studying climate
                   variability and its local impact.

               0   Expand the actual tidal-gauge network operating on the Venezuelan
                   coastal boundary, taking advantage of our participation in the Global
                   Observer System (GLOSS).
                            '1AR1111
            J@AN ('1'988@
                                         IIEN*EZUELA










                   Evaluate  the   feasibility of establishing      onshore  and   offshore
                   structures on critical coastal areas facing high risks due to sea level
                   increases.



                                                 395











              Centra7 and South America

                    0  Coordinate a long-term policy for reducing and reversing the ongoing
                       deforestation of Venezuelan territory.

                    0  Establish public education plans to promote better understanding of the
                       topic of climate change and to assess its potential impacts on society.

                    0  Motivate regional scientific centers related to environmental research
                       to establish studies that will address and identify the degree of
                       vul nerabi 1 i ty of  particular   geographical   areas    to    specific
                       climatological anomalies.

                    0  Stimulate research on alternate, nonconventional energy sources as part
                       of a long-term policy devoted to reducing the use of fossil fuels,
                       combined with more efficient use of energy, over the next few decades.

                    6  Organize the Venezuelan contributions to global research programs about
                       climatic changes and their implications, such as the World Ocean
                       Circulation Experiment, Tropical Ocean Global Atmosphere Programs and
                       the International Geosphere/Biosphere Program.


              CONCLUSION

                    In view of the clear evidence that climatological anomalies on the coastal
              area of Venezuela have the potential to induce serious social, economical, and
              ecological implications, the Venezuelan government should consider this topic to
              be a matter of urgency.    The need to compile inventories of natural coastal
              resources and existing environmental information must receive first priority, so
              that a worst - case cl i matol og i cal scenari o can be devel oped for the country. Th i s
              could provide an impact analysis that would facilitate the early implementation
              of an effective national policy.


              ACKNOWLEDGMENTS

                    Without the cooperation of the following members of the Venezuelan
              scientific community, it would not have been possible to produce this report.

                    Beatriz Vera (Universidad Central de Venezuela), Carlos Carmona (Universidad
              Nacional Experimental Francisco de Miranda), Jorge Alvarado (Ministerio del
              Ambiente y de los Recursos Naturales Renovables), Teniente Mario Capaldo
              (Direccion de Hidrografia y Navegacion), and Jose Luis Naveira (FUNDAOCEANO).

                    Also highly appreciated are data records provided by the Venezuelan Air
              Forces, Venezuelan Navy, and MARNR.






                                                    396










                                                                   Aparicio-Castro, et al.

          BIBLIOGRAPHY

          Aparicio, R. 1988. Some meteorological and oceanographic conditions along the
          southern coastal boundary of the Caribbean Sea (1951-1986). In: UNEP(OCA)/CAR
          WG.1 Report Implications of Climate Changes in the Wider Caribbean Region (in
          press).

          Bird, E.C. 1985. Coastline Changes. A Global Review. New York: John Wiley
          & Sons.

          Emanuel, K.A. 1987. The dependence of hurricane intensity on climate. Nature
          326(2):483-85.

          Maul, G.A., and K. Hanson.. 1988. Sea level variability in the intraamerican sea
          with concentration on Key West as a regional example. In: UNEP(OCA)/CAR WG.I
          Report Implications of Climate Changes in the Wider Caribbean Region (in press).

          Schubert, C., and M. Laredo.     1984.  Geology of Aves Island (Venezuela) and
          subsidence of Aves Ridge, Caribbean Sea.    Marine Geology 59:305-18.

          Shapiro, L.J. 1988. Impact of climate change on hurricanes. In: UNEP(OCA)/CAR
          WG.1 Report Implications of Climate Changes in the Wider Caribbean Region (in
          press).


























                                                 397











            IMPACTS OF AND RESPONSES TO SEA LEVEL RISE IN CHILE


                                         BELISARIO ANDRADE
                                          CONSUELO CASTRO
                                      Instituto de Geografia
                                Pontificia Universidad Catolica
                                           Santiago, Chile






           INTRODUCTION

                The latitudinal extent of Chile's Pacific coastline offers a wide variety
           of geomorphological and oceanographic situations. The coast extends from 180 to
           560 south, roughly equivalent to the latitudinal difference between Mexico's
           border with Guatemala and the Alaskan/Canadian border. If the indentation of the
           coast is taken into consideration, as well as the perimeter of numerous islands
           situated in the fiords region, the length of Chile's coastline is greater than
           25,000 km. Figure I shows the variation of Chile's coast.


           CHARACTERIZATION


           Natural Features

           Coastal Climatology

                The Chilean coast is under the influence of tropical, subtropical, and
           temperate climates of western continental margins. The ocean has an important
           moderating influence upon the temperatures. As Fuenzalida (1971) points out, the
           temperatures between 200 S and 300 S are 2.80C colder than the latitudes would
           suggest; between 50* S and 60* S they are 4.60C warmer.        Therefore, despite
           having a difference of almost 37 degrees of latitude, the difference of the mean
           temperature is only 12.80C. By contrast, there is a marked difference in the
           total amount of precipitation. In Arica at 180281 S, the total amount is 1.1 mm;
           on the other hand, in San Pedro at 47*431 S, the total annual amount is 4,076.1
           mm (Figure 2).

           Tides and Waves

                Tides in Chile are generally mixed-semidiurnal ; that is, two high waters and
           two low waters during a tidal day, with a diurnal difference.


                                                   399











              Central and   South America


                        A





                            . . . . . . . . . . .

































                        B















                                                                             SWUM*" -













              Figure IA-B.    Chile's 25,000-km coast varies considerably.         (A) Ritoque (32*
              481S) -- artificial foredune; and (B) Longotoma (320 221S)           sandy coastline.

                                                        400











                                                                         Andrade and Castro


                   C




























                    D















                                            flft-
                                     liar'.









           Figure 1C-D.    (C) Papudo (320 301S)       storm surge effect.    Beach is now
           replenished with dune sediments. '(D) Punta Con Con (32* 55'S)      Rocky coast,
           high terraces, with old stabilized dunes. By human interference, these dunes
           have been reactivated.

                                                 401











                                                                            ARICA                                                     LA SERENA                                                        VALPARAISO
                                                            Lat. IS 28'S Long. 70 20' W                                      Lat 29 64'S Long. 71 16-W                                       Lat. 33 01-S Long. 71 38-W
                                                                      altitude 6 mts.                                                 altitude 32 flits.                                               altitude 41 Mto.
                                                            40  1"*. 1 Cl             Prodo. IM"I   400                      40 Taw. I C1             PrecilL b"Ml      400                  40 1Tem. I Cl             pmew l"wq       400
                                                                                                    380                      351                                        350                  35t                                       .350
                                                                                                    300                      30@                                        .300                 30[                                       @300
                                                            25                                      @250                     20                                         -250                 25t                                       .250
                                                            201                                     200                      got                                        .200                 20L                                       @200
                                                                1                                                            at                                         loo                  151                                       .160
                                                            16  ,                                   150                      1                                                                                                         100
                                                            lot                                     100                      lot                                        100                  lot.
                                                                                                    so                       at                                         0                    5                                         60
                                                                                                    1                                                                   6                    . pri                             041,
                                                                                        --0                                  0  M                                       a                                                      A       10
                                                                j A 8 0 N 0 j F        M A M J                                  J A'S 0 N 0 J F M A M J                                         j A 9 0 N      0 j F M A'M

                                                                      TEMP. 90 PRECIP.                                                TEMP. -M PRECIP.                                                 TEMP. M! PRwv-





                        40b
                        CD


                                           CONSTITUCION                                                          VALDIVIA                                                 PUERTO AISEN                                                 CABO SAN ISIDRO
                                   Lat 36 20-S Long. 72 26-W                                        Lat. 39 48'S LoM. 73 WW                                             LaL 46 24'S Long. 72 42W                                       Lat. 53 47S Long. 70 68'W
                                              altitude 2 mts.                                                altitude 6 mt&                                                 altitude 10 111te.                                              aititude 20 mt&
                                   40  Tom. I Cl            Pffeim          400                       Ibwv I Cl              Pro= IMMI                                  40 TWW. I C1         PnP61L DMI   400                          40 ibm I Cl           P        IMM! 400
                                                                                                    40.                                    400                          so                                .350                         36                                 .350
                                   35@                                      350                     35                                     360                          30                                -300                         30@
                                   30t,                                     300
                                                                                                    Sol                                    Soo                          go                                250                          25
                                                                         1250                       26                                     250                          to                                200                          20.                                .200
                                   20.                                      200                     20                                     200                                                            160                          to.                                .160
                                                                            150                     is.                                    150                                                            100                          10,                                too
                                                                            too                     to                                     100                                                                                         @-!?"                           E160
                                                                                                                                           50                                                             so
                                                                            so                      6
                                                                            a                       0                                M j   0                            01 A80NDJFMAMJ                                                 J A 6 0 N      0 J F       A
                                       JAa0NDJFMA J


                                             TEMP. EM PRECIP.                                                TEMP.           PRECIP.                                        TEMP. M PRECIP.                                                  TEW EM PF1EW-
                                                                     M






                              Figure 2. Chilean coastal climatic types. Note the great pluviometric contrast and thermic homogeneity.











                                                                            Andrade and Castro

               The tidal ranges vary.       Between 180 and 410 S latitude, the maximum
          amplitude is between 1.5 and 1.9 m, respectively. Within the fiords region to
          the south, especially between the Gulfs of Ancud and Corcovado, tides are 5 to
          8 m because of a resonance effect. South of this sector, down to Punta Arenas
          at 520 S, the amplitudes vary between 1.8 and 2.5 m. There is a great contrast
          between the west and east entrances of the Straight of Magellan.            At Punta
          Dungeness, the easternmost point, the amplitude reaches 10 m, while at the
          western entrance of the straight the amplitude is only about 2 meters. At the
          Tierra del Fuego islands to Cape Horn, the range is between 1.5 and 3 meters.

               The information about waves on the coast, especially that collected with
          instruments, is scarce.      Data exist primarily for the central area of the
          country, where there seems   to be good correlation between wind patterns and wave
          patterns (see Appendix 1: Waves of Chile).

               Surges

               Storm surges occur occasionally on the Chilean coast; these are caused by
          large and intense atmospheric perturbances in the South Pacific, known as
          "Bravezas" in Chile.      According to Paskoff (1970), they progress along the
          coastline from south to north in the form of great waves, many meters above the
          usual height reached by the storm waves, and linger 24 to 48 hours' (see
          Appendix 1).

               Tsunamis

               Since 1652, over 30 tsunamis have been recorded on the Chilean coast
          (I.H.A.,   1982).    With an expected I-m rise, surges will          increase their
          penetration inland. Generated by earthquakes and submarine movement, these have
          devastating effects. As an example, on 13 August 1868, the tsunami that affected
          the Port of Arica dragged the North American ship Wateree for more than 2 miles
          from its anchoring ground and finally deposited it 400 m inland over the coastal
          dunes.




               'This author's description of the morphologic effects and the wave levels
          reached during an event that occurred in 1968, which affected a coastal sector
          of approximately 2,500 km between Arica and Talcahuano, coincides with one
          presented by Araya-Vergara (1979). In 1968, a number of roads located more than
          5 m above sea level were destroyed by waves, as were hotels, houses, and
          restaurants, which had foundations 5-7 m above sea level. In general, all points
          near the coastline situated at the holocene level "La Vega" (1-2 m) were affected
          by the "Bravezas," and various points situated above the Pleistocene level
          "Cachagua" (5-7 m) were also affected (for example, the airstrip of the naval
          aviation base at Quintero). The foredunes of various beaches of central Chile
          were eroded.     The effects produced by these spasmodic phenomena, not very
          frequent, are long lasting and much more notorious than the effects of continuous
          wave action related to the usual storms occurring over several years.

                                                   403











              Central and South America

              Coastal Geomorphology

                   The Chilean coast between 18* S and W S is dominated by marine processes,
              acting under hyperarid, semiarid, Mediterranean, and oceanic temperate climates,
              with rocky coasts and pocket beaches dominating. To the south of this sector,
              oceanic temperate climate dominates, with domination by marine processes along
              the open coast to the west and fluvial domination in the inland fiords (Figure
              3) (Appendix 2 provides more detail).

              Neotectonics

                   A particular characteristic of the Chilean coastline is its great vertical
              mobility, the result of its location in a plate convergence zone. Because of
              this, strong movements of uplifting and sinking occur with magnitudes that
              surpass those expected from a sea level rise induced by the greenhouse effect.
              For more than a century, the data of various authors have shown that the
              magnitude of the vertical movements can frequently exceed 150 cm (Meneses Toro,
              1897; Vidal Gormaz, 1901; Saint Amand, 1963; Pflaker and Savage, 1970; Fuenzalida
              and Harambour, 1984; Gonzalez, 1985).

                   It cannot be clearly distinguished whether the tendency is toward downfall
              or uplifting, because in some latitudes the coast has moved in both directions.
              However, there seems to be a slight predominance of uplifting north of 390 S and
              sinking south of this latitude.

                   The most recent movements have been determined by I.G.M. (1985), who found
              a mean uplift of 33 cm in the coastal sector of San Anton i o-Al garrobo
              (33-20'-33030' S) due  to the earthquake of March 3, 1985.     Barrientos et al.
              (1981), using the tide  gauge of Puerto Montt (41* S), indicated an uplifting of
              the region of about 4.7 cm/year between 1964 and 1973, diminishing to 2.4 cm/year
              between 1980 and 1985; this same site sank 200 cm during the May 1960 earthquake.

              Cities and Population

                   The population of Chile is approximately 12.5 million, 80% of which is urban
              and mainly concentrated in Santiago. The urban coastal population represents 21%
              of the total population, and a large part of it resides in urban areas of more
              than 100,000 inhabitants. The regions of Valparaiso and Bio-Bio together contain
              55.35% of the total urban coastal population of the country.

                   The main coastal cities are located on coastal stepped plains separated by
              dead coastal cliffs. At first, the cities were located over the low (between 5
              and 20 m) and narrow marine terraces but later they grew toward the higher
              terraces (Figure 4).

                   The main tourist centers are the sandy coasts of Coquimbo Bay (29* S) and
              the central coast (33030' S).    The bathing resorts extend over coastal dunes,
              including the foredune. Protection structures for wave action are infrequent,
              except in places where adequate structures for ports have been built, e.g.,


                                                     404








                                                                                                                                                           Andrade and Castro


                                                                                                                              .0
                                                                                     100              010




























                                                                                                                                                                 500












                                                                                                               lio ClIdene
                                                                                                               Milillco


                                                                                                 36.-




                                                                                                                                                                  40




                                                                                                                                                             SCn Kin
                                                                                (Simplified after Ki mer


                                                                       Older resistant                                    Sand beach or barrier island


                                                                       Low resistant                                      Packet beach
                                                                       Glacial and glacial fluviol         E.-            Rock
                                                         ff-f High relief              cliffed                            Regme

                                                                       Low relief      cliffed                            Subregirne


                       Figure 3. Coastal landform types.

                                                                                                            405








                         Central and South America                                  ANTOFAGASTA         230 39' S.)








                                                                                                                                  LA SERENA (29054' S.)
                                      IQUKM (200 12' S.)

                                                                                                                 @250                       ry

                                         P A C I F I C



                                                                                                                                              to
                                          0 C CAN                                                                                                              115



                                                                                                                                                         2w


                                                                                                 4@


                                                                                             IWI
                                                                                                 900                                              $57
                                       URBAN AREA                                    URBAN AlK                                    U     ANNE
                                             less       em         R"s             IM 1904   a     filso -ftws                        1093 ff@ ffft         R"ds



                                      'VALPARAISO C,33002'S.)

                                                                       PACIFIC    OCEAN
                                                                                                                             PUNTA ARENAS (53010'S.)

                                                                                                 foo


                                                                                                 150




                                                                                                 200
                                                                                                                                                            ow

                                                                                                 250


                                       MEAN AN A
                                           11097 6 1977                                                                                                 srffAir
                                                                                                                                                          or

                                                                                                                                                    UAGALLANES



                                      PUERTO MONTT
                                      (41029'S.)                                                                                                   IF

                                                                                                                              URBAN AREA
                                                                                so                                                t900      197-5 -Reads
                                                        W9




                                                                         UNO
                                               DO                         cc
                                                              77,41.  119LONCAVI

                                          URBAN AREA
                                             9S
                                                MO
                                                    NrT











                                               .0                         0.
                                                                 I. R'LONCAv,
                                            -   @.@A
                                           M   goo EM 1979 -ftesift


                        Figure 4. Some Chilean cities located over marine terraces.

                                                                                               406










                                                                        Andrade and Castro

          docks, marinas. With a sea level rise of about 1-2 m, these bathing resorts will
          be only somewhat affected.

          Economic AsRects

               The National Accounts give an idea of the relative importance of some
          economic activities held in the coastal zone.     The Gross Domestic Product was
          $18.5 billion (U.S. dollars).    Tourism (primarily coastal, but incorporating
          activity from all over the country) accounted for 0.94% of this total, and
          fishing accounted for 0.88%.


          IMPACTS OF SEA LEVEL RISE

               The existing coastal national maps of Chile do not permit a quantitative
          evaluation of the area affected by a sea level rise of 20 and 200 cm, given that
          maps have contour intervals of 25 m or greater.

          The Rocky Coastline

               Considering the steepness of the rocky coast along its 30,000 km, a sea
          level rise of 20 cm will not have any noticeable effect. A 50- to 100-cm sea
          level rise would probably affect scarce coastal tourist installations, but only
          during storms.

               A rise of 200 cm would produce effects on harbor structures, requiring their
          redevelopment, as happened in the tectonic sinking of 1960. A sea level rise of
          100 to 200 cm would accelerate the recess of cliffs in soft rocks (sandstone) of
          the central zone of Chile, affecting populated centers, essentially tourist
          centers.

               South of 410 S, the attacking of the cliffs created in soft glacial outwash,
          will affect a great number of populated centers of the eastern coast of Chiloe.
          Coastal protection works would be necessary in this sector.     We estimate that
          over 60 km of seawall will be necessary to shelter the threatened areas.

          The Sandy Coastline

               Although they constitute only 2.1% of the total coast, sandy shorelines
          support important economic activities (tourist and industrial as well as
          residential). All the pocket beaches are located in front of cliffy landscapes,
          so they cannot migrate inland in the eventual case of a sea level rise.

               A sea level rise of 50 cm or more will substantially diminish the area of
          pocket beaches. A rise of 2 meters would eliminate them completely.

               The sandy shorelines associated with dune fields have an important sediment
          supply from the rivers and enough space to shift inland.     In this case, a sea
          level rise of 50 cm or more will affect the foredune, making it retreat inland.
          Important industrial facilities would be affected, particularly those at Quintero

                                                 407









              Central and South America

              Bay (32*46' S), San Antonio (33033' S), Constitucion (350181 S), and Talcahuano
              (360421 S). Approximately two-thirds of all the coastal bathing resorts would
              be partially inundated.


              RESPONSES

              Institutions and Agencies Associated With the Coastal Zone

                   The national administrative organizations related to the coastal zone are
              within three independent ministries:

                   1. Ministry of National Defense, Marine Subsecretary, which consists of

                       a.  General Office of the Marine Territory and Merchant Marine. This
                           organization has the control and monetary responsibility for the
                           entire coast, territorial sea, and exclusive economic zone of the
                           Republic.    Its inland jurisdiction extends 80 m inland, starting
                           at the limit of the spring high tide line. The essential mechanism
                           for control of the coastal area lies with the members of this
                           office, who permit the particular use in any form of beaches, beach
                           lots, the sea floor, portions of water, and rocks within and/or out
                           of the bays.     The agency also has responsibility for       issuing
                           permits for extraction of sediments and landfill for          coastal
                           engineering.

                       b.  Navy Hydrographical Institute.     This agency is in charge of all
                           studies and preparation of documents for navigational aid,    such as
                           tide tables, marine navigational charts, and navigational     tracks.
                           It is also in charge of meteorological forecasting and doing basic
                           research in oceanic and coastal physical oceanography.        It is a
                           member of the International Tsumani Alarm System of the Pacific.

                   2.  Ministry of Public Works, Harbor Works Office.        This agency is in
                       charge of the design, calculation, and studies of harbor works, and
                       conducts research in coastal oceanography.

                   3.  Ministry of Economy, National Fishery Service. Administers the fishery
                       sector, promotes and coordinates investigation in this domain. This
                       office is in charge of the methods and installations of aquaculture,
                       fishing quotas, and extraction of live products from the littoral zone.

                   The previously named institutions, together with other institutions from a
              group of Chilean universities, form the CONA or "Comite Oceanografico Nacional"
              (National Oceanographic Committee).

                   The CONA has prepared a National Oceanographic Plan for the period 1987-97,
              which is based on a four-year survey of national institutions concerned with



                                                     408











                                                                            Andrade and Castro

          oceanic scientific technological work. Five research programs are proposed to
          investigate the structure and interrelationships of ecosystems within Chilean
          seas.

          Agency Perceptions About Greenhouse-Induced Sea Level Rise

               Conversations held with members of some of the relevant agencies suggest
          that a sea level rise of 20-50 cm is not perceived as a problem. Because there
          is a lack of awareness concerning a greenhouse effect-induced sea level rise, no
          one is planning a response to it.        Local planners are more concerned about
          solving current problems; nevertheless, they indicate that when it becomes
          necessary to protect small fishery facilities or installations in contact with
          the beach, they will support solutions based on seawall tetrapods.

               Also, due to the effects of strong winter storms, some tourist beaches have
          been nourished with sand.     The filling is done with sediments extracted from
          inland deposits. In some cases, the foredune has been elevated using mechanical
          and vegetational methods. This is done because of dune management and not as a
          response to a marine erosion.

               Frequently, local planners have been forced to respond to tectonic sea level
          rising, but this is not predictable and for this reason they do not consider a
          slow sea level rise of 20 to 50 cm over many years to be an emergency.

               Chilean government agencies will be able, from a technological point of
          view, to apply protective actions in critical areas when the problem is
          adequately evaluated.























                                                   409










               Central and South America


                                           APPENDIX 1: WAVES OF CHILE


                    The reports that give the most adequate synthetic view are those of
               Araya-Vergara (1971, 1979); both are on central Chile. The information provided
               by Davies (1980) based on the works of Holcombe (1958) and Meisburger (1962)
               gives a very useful integrated view.

                    Holcombe (1958) concluded that in the Southern Hemisphere, the mean latitude
               of the zone of maximum value of gale force winds oscillates only between 540 S
               and 56* S during the winter-summer period. Because of this persistence of high-
               frequency gale-force winds and the length of the fetch, the southern storm belt
               is the most evident and important wave-generating area in the world and produces
               a high proportion of the world's ocean swell (Davies, 1980).

                    The path followed by the swell generated at latitude 55' S in front of the
               Chilean coast produces wave trains with a west and southwest component from 410
               S toward the north. This pattern of waves makes the coast of      Patagonia the most
               attacked by storm waves during the year.

                    With the data compiled by Meisburger (1962), Davies presents various
               synthesis charts in which it is possible to appreciate that for the Chilean
               coasts the frequency of occurrence, in at least half the year, of waves of 2 m
               or higher is as follows:

                                       South Latitude                    %

                                       380 - 560 ..................     > 40
                                       380 - 300 .................. 30 - 40
                                       300 - 250 .................. 20 - 30
                                       250 - 180 ..................  10 - 20

                    The greatest height reached by waves occurring with a frequency of 3% or
               greater in at least half the year is as follows:

                                       South Latitude       Height (m)

                                       560 - 450 ...........     > 6.0
                                       450 - 400 ........... 6.0 - 5.0
                                       400 - 220 ........... 5.0 - 3.7
                                       220 - 180 ........... 3.7 - 2.2

                    In   a   more   detailed   scale,    Araya-Vergara    (1971)   shows   the    wave
               characteristics in Chile, according to the works of D.O.P.-Tudor Eng. Co. (1965),
               as well as the unedited reports of the Laboratoire Central d'Hydraulique de
               France, for Constitucion (35*18' S) and San Antonio (330351 S). The results of
               his analysis indicate that the origin of the most frequent waves is from the
               southwest, which coincides with the prevailing winds.



                                                        410











                                                                      Andrade and Castro

              In Arica in December 1975 and July 1977, with a total of over 3,396 waves
        recorded, the mean period during the summer had a value of 12 seconds and a
        significant height of 1.15 m; during winter the mean period was 9 seconds and the
        significant height was 1.3 m.

              In Iquique there are only data for the month of June 1987. Using 1,336
        waves, the mean period was 11.02 seconds with a significance height of 1.08 m.

              The wave data are scarce and discontinuous. They refer only to a sector
        of the coast dominated by the southern west coast swell environment.

              There are no automatic wave records situated along the coast dominated by
        the southern storm wave environment, especially south of 410 S.

              Important differences between the coast facing directly the open Pacific
        and those of the interior waters of the fiord coast probably exist.
































                                               411










             Central and South America

                                    APPENDIX 2: GEONORPHOLOGY OF CHILE



             Distribution of Cliffed Coasts

                   According to Araya-Vergara (1982), the length of the cliffed and rocky
             coastline is 33,711 km; 700 km of the northern region of Chile correspond to the
             mega-cliff described by Paskoff (1978), along which can be distinguished four
             sections. The first section, between 18*28' S and 20*13' S, is an active cliff
             with unevenness between 400 and 1,000 m; a second section between 20*13' S and
             21'24' S is a dead cliff behind a terrace 2 to 3 km wide;          a third section
             between 21*24' S and 23*28' S, with unevenness between 500 and 1,200 m, is also
             a dead cliff with a terrace in front, composed of marine Miocene deposits,
             sculpted by the sea; the fourth section, which reaches 25*22' S, presents active
             and dead sectors, with mean heights of 500 m, but in some places it can reach an
             altitude of 2,000 m. This is a major feature of the north coast of Chile. In
             general, in this sector hard rocks appear on the surface, giving a stable
             appearance.

                   South of 250 to 33044'S there are predominantly cliffs and bluffs in
             essentially igneous formations. Another section also with predominance of cliffs
             but in tertiary soft sedimentary rocks as well, is developed to 36*30'S. From
             this sector to 43*30'S are hard cliffs sculpted in micha-schists alternating with
             soft tertiary sandstone.    It is also possible to distinguish an internal sector
             between 410 S and 430 S with soft cliffs sculpted essentially in glacial outwash,
             but in sheltered environments. From 430 S to 560 S, hard rock cliffs and bluffs
             dominate with some morainic intercalations.

             Distribution of Low Unconsolidated Coasts

                   The lower coasts, including the deltas, constitute 2.1% of the total;
             according to Araya-Vergara (1982) they add up to 580 km. They are discontinuous
             and concentrated in groups related with the existence of fluvial sedimentary
             sources and with a minor association, to soft sedimentary rocks at the shoreline.
             The main groups of beaches   which can be distinguished are the following:

                                  290 S - 300 S ........... Coquimbo   La Serena
                                  320 S - 330 S ........... Longotoma   Concon
                                  330 S - 370 S ........... Chile Central
                                  380 S - 430 S ........... Arauco - Chiloe

                   In general they are    in dynamic equilibrium, with not much evidence of
             retreat or advance in the long range. However, Andrade (1985) has found evidence
             of recession in the Chiloe coast, in the internal sector. It may be explained
             by a relative sea level rise due to recent subsidence movements and applications
             of the Bruun rule.

                   Most of the constructed coasts correspond to beach ridges, composed of
             sand. In the interior coast of Chile spits and hooks are very frequent, formed
             by sand and gravel that the sea extracts from the cliffs sculpted in glacial

                                                     412










                                                                         Andrade and Castro

         outwash. At Tierra del Fuego it is common to find beaches supplied by morainic
         deposits.

               A great number of beaches along Chile correspond to pocket beaches, which
         are located over rocky platforms between resistant rocky promontories. Although
         data are scarce, our observations from fieldwork in central Chile indicate that
         they have a general thickness less than 4 m at the backshore.

               A frequent phenomenon in central Chile is the development of coastal dunes,
         associated with beaches which are generally located north of the river inlets.
         This ensures a good sedimentary supply because of the longshore drift generated
         by waves mainly from the southwest, which coincides with the prevailing winds and
         which also transports the sand inland.

               The principal coastal dunes are located between 290 S and 420 S.          They
         cover approximately 131,000 hectares, according to the inventory made by
         IREN-CORFO (1966). Most of the modern active dunes are located between 330 S and
         380 S according to Castro (1985).

               Castro (1985) provided a synthesis of the different morphologic elements
         found in the coastal dunes, distinguishing:

               a) The foredune.

               Located in contact with the backshore forming a parallel band to the beach,
         its width is variable between 50 to 200 m; the average height is 5 m. There is
         a close association between the morphologic aspect of the dune and the vegetation
         found on it.    Thus in central Chile, the foredune is composed of a group of
         hummocky dunes, elongated in the direction of the wind, with a pointed tail to
         leeward. They are separated by deflation corridors.      There are obstacle dunes
         produced by the capture of sand by vegetation . The most frequent species is
         Ambrosia chamissonis, which possesses a radicular system which develops to great
         depth; it is an accidentally introduced species from California (Kohler, 1970),
         which apparently is substituting for the native species Carpobrotus chilensis,
         which helps form lower dune hummocks.

               The Chilean foredune does not have the aspect of a continuous wall as in
         North America or the northwest coast of Europe, colonized by Ammophila arenaria,
         but has aspects of a nebkha field.     In some places where dune control has been
         applied with Ammophila arenaria, the foredune gives a massive appearance as in
         the case of Chanco (350 S).

               b) Interdune depression.

               A depression separates the foredune from the moving sand ridges of the
         interior.   It has a variable width; its major axis is parallel to the beach,
         frequently comprising an active deflation area and sand transportation area. But
         on occasions, it may be occupied by a coastal lagoon or a marsh.    In this sector
         the water table is very close to the surface, so it has vegetation adapted to


                                                 413









             Central and South America

             these conditions such as Scirpus nodosus. The depression may also develop by the
             deflation of old coastal ridges.

                   c) Moving sand ridges.

                   These occupy the greatest area within the dune field. They have a variety
             of forms, in which we can distinguish some individuals, such as barkhans. The
             coalescence of barkhans leads to transverse dunes which are organized as waves
             moving to the interior many hundreds of meters, invading agricultural lands and
             villages. They do not have vegetation cover.

                   d) Stabilized dunes.

                   Frequently in contact with active dune fields are various    generations of
             dunes stabilized by natural vegetation.       A variety of this    group are the
             longitudinal dunes, which appear within this axis in the same direction as the
             prevailing wind. They present associations of Paya chilensis and Cereus sp.

                   Other morphological types are the undulated dunes.       Their vegetational
             layer is composed by low gramineous and bushes such as Baccharis concava.

                   Both of the described stabilized dune forms are dated as Holocene (Paskoff.,
             1970; Caviedes, 1972). Holocene dune reactivation can be verified in many places
             starting as blowouts, evolving on occasion as parabolic dunes. The origin of the
             reactivation is normally because of human interference.

                   A third variety of stabilized dunes corresponds to hills which are smoothly
             undulating and which have not lost totally their original form due to natural and
             anthropic causes. Paskoff (1970) assigns them a Pleistocene age. They may be
             covered by mesomorphic scrub bush more or less dense.

                   A sea level rise of 1 m could affect rapidly the foredune, but the Holocene
             dunes would not be affected immediately.

             Distribution of Aquatic Features

             Wetlands

                   Although there has been no inventory of wetlands in the country, or
             estimates as to the dimension or nationwide distribution of wetlands, a few
             reports give us a general idea of their morphology and their floristic
             composition.

                   Geomorphologically, Andrade (1985) described some tidal marshes on the Gulf
             of Ancud showing morphological patterns similar to those of the temperate zone
             of the Northern Hemisphere. In this study area they show evidence of erosion by
             the sea due to a tectonically induced sea level rise caused by crustal
             subsidence.




                                                    414










                                                                       Andrade and Castro

              In relation to their requirements of low wave energy and great tidal range,
         they tend to develop better between 400 and 430 S in protected positions in
         estuaries or behind sand barriers. In the botanic studies done by Ramirez et al.
         (1988), Schwaar (1978), and Reiche (1934), some of the halophytes described are
         Triglochin maritimun, Cotula coronopifolia, Eleocharis melanostachys, Selliera
         radicans, Spartina densiflora, and Sal icornia sp. In general, the tidal marshes
         develop adjacent to a cliffed landscape in the Gulf of Ancud. A rapid sea level
         rise would probably endanger the permanency of these intertidal ecosystems, since
         in many cases they do not have space to migrate upslope because they are bounded
         by bluff coasts.







































                                               415









                                                                91t

                                      2                00012     :  I
                                      E                000't     :  I              oz              ooolos        :  I
                                      03               000's     :  1              9               000,09        :  I
                                      s                00019     :  I              I               000IS9        :  I
                                      I                009'L        I              E               000'OL        :  I
                                      oz               00018        1              1               000'GL        :  1
                                      V6               000,01       1              z               000,08        :  I
                                      9                ooo,zI       I              El              000,001       :  I
                                      I                00SIZI       I              I               oooIszI       :  I
                                      ES               0001ST       I              I               00010cl       :  I
                                      z                000,91    :  1              8               ooolosi       :  I
                                      U                0001oz    :  I              I               ooo,sqI       :  I
                                      I                oooltz    :  1              91              00010oz       :  1
                                      61               ooolsz    :  1              3               ooolosz       :  I
                                      ot               00010E    :  I              1               000,093       :  I
                                      t                oooIzc    :  1              01              oooloos       :  I
                                      s                ooo,sc    :  I              z               000,00011     :  I
                                      SE               00010V    :  I              z               000,0001Z     :  I
                                      z                0001st    :  1              3               000,0001C     :  I

                               SPP40 10 'ON               OLP:)s           SPR43     10 -ON              OLRDS

                                                                           -aLPOs  43EB JOJ sjjp4D jo jaqwnu
               944 94POLPUL SLUO Mm 9m OJOIOJB44 !kja[JeA OLPOS J84PBJB P SL BJ944 lasodind
               3LItoads s4i o4 ana         *,kLMjjed kj4unoD 841 JOA03 's4JP4:) W91' 844 se LLOm sP
               1641 *SAaj,8W UL       eleP 3P48wk44eq ROO apnPUL           S4.Ae4:) LeUOLje6LAeU VHJ 841

                                         W os V sz                         s  lot
                                         W os I sz                         S    LE
                                           os                              s  .1c
                                         W OTIV sz                         s  10E                         ooolsz:l
                                         w 'OSIV! SZ             S  oLt -  S    81                        00010s:1

                                         W 001 V os              S  oLZ -  S  oSI                        0001001:1
                                              kosz                         s  AS
                                              W; osz                       s  ocs
                                              tu 093             S  oLZ -  S  o8f                        00010SZ:1
                                         8Ajn3:wjqj              s  09S -  s  081                        000,00s:1

                                 LeA.AOIUI ano4uqjj@            J0430S Le4seoj                                ale:)s

                                                                :8Le3s 844   04 BULPJO33e XLP[4jed Xj4unoo
               B44 ABAO:) PUe 'SUOL4:)aCo.Ad pue s8Le:)s snOL.AeA U[ 4s@xB sWeV W9I a4i
               -sWeV LeUOL            AeU sanpo@d kwaft puoaas a44 pue 'S4Je43 3L4dej6odo4 soonpoad
                               .46L
               9:)U96e 4SALJ                                    8P 0:)Lje.A60.Ap!H o4n4[
                                  841    '(VHI) ePew-AV eL                                 4suI 844 Pup (W91)
               Je4[L[W 03[jeJ6009 o4n4@4suj aq4 :8SUaj8a JO ka4SLULW 844 JO SB[3ua6e om4 kq
               pa4nqJ4SLP PUe poongoad:aup s4uawnoop OL4deaft4jeo OWBM kLM43e 841


                                                  viva DlHdVHSOIOHd IVIH3V
                                         aNY 3IHdVHSOIHV3 31BY11VAV :E XlaN3ddV

                                                                                   eaijetuV qjnoS pup 1piluej











                                                                            Andrade and Castro

              There are various vertical aerial photo missions.            The Photogrametric
         Service of the Air Force (SAF) is officially in charge of producing this type of
         document. However, many other missions produced by other agencies in the past
         are available.


                Year             Approx. Scale              Latitude              Agency

                1942-45           1  : 30,000                   ?                 USAF
                1955              1  : 70,000            17030'- 37010'S          HYCON
                1961              1  : 20,000                370- 38*20'S         HYCON
                1961              1  : 50,000                370- 43030'          OEA
                1974-75           1  : 55,000           32015 -  340              SUSAF
                                                        43030 -  510
                1978-80           1  : 30,000             330 -  410S             SAF
                1978-80           1  : 60,000              180 - 560S             SAF


                On occasion, other   charts and aerial photographs,   which were produced for
         specific uses, can be obtained through public and private organizations. These
         documents are not standard issues; therefore, there are no general indices for
         them.


































                                                  417











                Central and South America

                BIBLIOGRAPHY

                Andrade, B. 1985. Estudio morfosedimentologico de marismas del Golfo de Ancud,
                Chile. Revista de Geografia Norte Grande 12:27-33.

                Araya-Vergara, J.F. 1971. Determinacion preliminar del las caractersticas del
                oleaje en Chile central.        Not Mens. Museo Nac. Hist. Nat. Santiago, Chile
                15(174):8-11.

                Araya-Vergara, J.F. 1972. Bases geomorfologicas para una division de las costas
                de Chile. Informaciones Geograficas 22:5-36.

                Araya-Vergara, J.F. 1976. Reconocimiento de tipos e individuos geomorfologicos
                regionales de la costa de Chile. Informaciones Geograficas 26:9-30.

                Araya-Vergara, J.F. 1979. Las incidencias cataclismaticas de la bravezas en la
                evolucion de la costa de Chile. Informaciones Geograficas 26:19-42.

                Araya-Vergara, J.F. 1982. Analisis de la localization de los procesos y formas
                predominantes de la linea. litoral de Chile: Observacion Preliminar.
                Informaciones Geograficas 29:35-55.

                Barrientos, S., S.N. Ward, and E. Lorca.      1981. El terremoto de 1960 en el sur
                de Chile y sus deformaciones cuasi-permanentes. Comunicaciones 39:158.

                Canon, J.R., and E. Morales.        1985.    Geografia del Mar Chileno.         Colecion
                Geografia de Chile. Santiago, Chile: I.G.M. Vol. IX., 244 p.

                Castro, C.     1985.    Resena del estado actual de conocimiento de las dunas
                litorales en Chile.    Rev. de Geografia de Chile Terra Australis 28:12-32.

                Castro, C. 1988. The Artificial Construction of foredunes and the interference
                of dune-beach interaction. Journal of Coastal Research (Special Issue No. 3).

                Caviedes, C. 1972. Geomorfologia, del cuaternario del Valle del Aconcagua. Chile
                Central. Cuad. Geogr. Friburg No. 11.

                Davies, J.L.    1964.    A morphogenic approach to world shorelines.         Zeit. fur
                Geomorph. 8:127-142.

                Davies,   J.L.      1980.     Geographical    variation    in   coastal    development.
                Geomorphology Texts No. 4. London: Longman. 212 p.

                D.N.H.A.    1961.   El maremoto del 22 de Mayo de 1960 en las costas de Chile.
                Publicacion No. 3012. Valparaiso, Chile: Departmento de Navegacion e Hidrografia
                de la Armada. 129 p.

                Fuenzalida, R., and S. Harambour.            1984.    Evidencias de subsidencia. y
                solevatamiento en la peninsula de Brunswick, Magallanes. Comunicaciones No. 34.
                Sanitago, Chile: Universidad De Chile, p. 117-120.

                                                          418











                                                                               Andrade and Castro

           Fuenzal i da- Ponce, H. 1971. Climatlogia de Chile. Santiago,      Chile: Universidad
           de Chile, Departmento de Geofisica y Geodesia. Publicacion Interna de la Seccion
           Meteorologia. 73 p.(

           Gonzalez, O.M. 1985. Mapa neotectonico preliminar de America del Sur. Ceresis.
           Santiago, Chile: I.G.M.

           Holcombe. 1958. Similarities and contrasts between the Arctic and the Antarctic
           marine climates. In Polar Atmosphere Symposium. Part 1. Metheorology. London:

           I.G.M. 1985. El terremoto del 3 de Marzo de 1985 y los desplazamientos de la
           corteza terrestre. Rev. Geog. de Chile Terra Australis 28:7-12.

           Inman, D.L., and C.E. Nordstrom.          1971.    On the tectonic and morphogenic
           classification of coasts. Journal of Geology 79:1-21.

           I.H.A. 1982. Instituto Hidrografico de la Armada. Maremotos en la costa de
           Chile. Publicacion 3016. Valparaiso, Chile: I.H.A. 48 p.

           IREN-CORFO. 1966. Inventario de dunas en Chile (29* 48' - W 50' Lat. sur).
           Publicacion No. 4.     Instituto de Investogaciones de Recursos Naturales CORFO.
           20 p. July.

           King, C.A. 1977.     Classification and morphometry of the coast between 200 S and
           420 S. Rev. Geog. Valparaiso 8:27-57.

           Kohler, A. 1970. Geobotanische untersuchungen ankustendunen Chileswischen 27
           and 42 Grad. Sud. Breite. Bot. Jahrb 30:50-200.

           Kohler, A. 1967. Die entwicklung der vegetation auf kustendunen mitelchiles.
           Umschau in Wissenschaft und Technik. 20/67:666-667.

           Meisburger, E.P. 1962. Frequency of occurrence of the ocean surface waves in
           various height categories for coastal areas.        U.S. Army Engineer Research and
           Development Laboratories. Report 1719-RR.

           Meneses, T.J.N.     1897.    Jeografia de Chile.      Santiago, Chile:     Imprents El
           Comercio. 159 p.

           Orson, et al. 1985. Response of tidal salt marshes of U.S. Atlantic and Gulf
           coast to rising sea level.       Journal of Coastal Research l(l):19-37.

           Paskoff,  R.   1970.    Le Chili semi-aride.     In:   Recherches Geomorphologiques.
           Bordeau,  France: Biscaye Freres. 420 p.

           Paskoff,  R. 1978. Sur 1 'evolution geomorphologique du grand escarpement cotier
           du Desert Chilien. Geogr. Phys. Quat. 32(4):351-360.

           Pflaker, G., and J.C. Savage. 1970. Mechanism of the Chilean earthquakes of May
           21 and 22, 1960. Geol. Soc. Amer. Bull. 81:1001-1030.

                                                     419











              Central and South America

              Ramirez, C. et al. 1988. Estudio vegetacional de una marisma del centro-sur de
              Chile. Medio Ambiente 9(2):21-30.

              Reiche, C.    1934.   Geografia botanica de Chile.       Santiago, Chile:       Imprenta
              Universitaria.

              Saint-Amand, P.    1963. The Great Earthquakes of May 1960 in Chile. Washington,
              DC: Smithsonian Institution. pp. 337-363.

              Schwaar, J.    1978.   Halophyten-gesellschaften in Sudchile.       Verhandlungen der
              Gesellschaft fur Okologie Kiel 1:409-411.

              Tudor Eng. Co. 1965. Report for a Waterfront Facility. Constitucion, Chile.
              San Francisco, CA: Tudor Eng. Co. 276 p.

              Vidal Gormaz, F.     1901.    Hundimientos i solevantamientos verificados en las
              costas Chilenas.     Revista Chilena Hist. Nat. (Valparaiso) 5(10):213-224.
































                                                        420









                         LIVING STRATEGIES AND RELOCATION
                                       IN LATIN AMERICA



                                          CRISTINA MASSEI
                          Fundacion Ambiente y Recursos Naturales
                         Moreno 2142, 1428 Buenos Aires, Argentina






          ABSTRACT

               Accelerated sea level rise will produce multiple and irreversible
          transformations locally, regionally, and nationally in Latin America.          Such
          changes will not only involve geographic and economic aspects of the countries,
          but also will produce irreparable losses to their historical and sociocultural
          inheritance, particularly in the affected communities.

               This paper focuses on how to study the implications of relocation, not the
          implications themselves, with particular emphasis on "strategies for living" with
          the relocation of affected communities, which is at present a well-known concept
          in the Latin American social sciences field. This criterion makes it possible
          to account for all the dimensions of social effects -- i.e., demographic,
          socioeconomic, or cultural.    It is defined as "the way in which the community
          is organized and uses its environment." The family group is the primary unit
          of analysis; the local community is also considered.

               Because most inhabitants near the shore are subjected to marginal economies
          bordering on poverty, such "strategies for living" may be little more than
          strategies for survival.


          INTRODUCTION

               In Latin America, sea level rise will have multiple and irreversible social,
          economic, and cultural effects locally, regionally, and nationally.           These
          effects will be so extensive that even the interior provinces will be affected,
          because national transport, services, trade, and production centers are located
          on the coast. Direct damages to these centers will affect national activities
          and will bring about new physical, social, economic, and cultural configurations,
          significantly restructuring communities and the future historical process.

               The resettlement process is a social process that frequently is overlooked
          in favor of the costs of flood damages, coastal defense, and other physical
          effects of flooding.    Frequently, poor families settle in coastal areas near
          cities because urban centers supply services, consumer goods, and transitory and

                                                 421








              Central and South America

              informal work sources. Consequently, we must design a relocation policy that
              takes into account not only the losses of goods and dwellings, but also the
              disruptions in the formal and informal links of the local community at all
              levels.

                   We have developed a "living strategies" concept for the population in
              general and "survival strategies"    for the most impoverished sectors.       These
              strategies account for all the       demographic, socioeconomic, and cultural
              dimensions that must be considered   when relocating communities.    According to
              Cernea (1989), in general, previous efforts to relocate communities have often
              failed because people focused on     physical logistics and underestimated the
              social, cultural, political, and labor-market effects.

                   This paper lays out an analytic structure by which one could analyze the
              social effects of relocation strategies.     We warn the reader at the outset,
              however, that the paper does not specifically address the effects themselves.


              THE RESETTLEMENT PROBLEM

                   Involuntary displacements of population due to sea level rise would cause
              economic and cultural shocks to many communities and destroy production goods,
              valuable natural resources, and the local environment. Such displacements would
              also create problems in areas that receive the transplanted population, because
              if vacant land were scarce, the available natural resources would be severely
              taxed (Cernea, 1989). Partridge (1983) wrote "the relocation process destroys
              a pre-existent form of life."    It transforms "every form of life, in all its
              different aspects, such as institutional and social ones, economic systems,
              guidelines to the community organization, power structures', everyday activities,
              or the cultural tradition."

                   Because having one's hometown destroyed can give people a feeling of
              helplessness, relocation strategies should focus on returning to the people some
              control over their own lives, similar to the control they previously had. (It
              cannot be exactly like the original          control,  because the preexisting
              socioeconomic organization will not exist after the resettlement.) In addition,
              officials in Latin America must take three important factors into account:      (1)
              the characteristics of the people to be relocated:       in general these people
              belong to the lowest socioeconomic stratum, which is why the relocation problem
              is inseparably linked to the survival of these sectors; (2) the sociocultural
              identity crisis, which makes people question the efficiency and validity of their
              traditional strategies and survival schemes and increases their uncertainty to
              such an extent that it immobilizes their capacity to respond; and (3) the impact
              produced on social relations networks, on the existing leadership structure, and
              on the behavioral guidelines.


              METHODOLOGICAL APPROACH

                   Analyses of resettlement strategies should follow three guidelines:         Do
              not collect socioeconomic and cultural data without taking into account the model
              of possible relocation policy. On the contrary, put the data in the order of

                                                     422









                                                                                      Massei

           the model from the precise moment of their recollection, description, and
           analysis. Otherwise, the data will not be read in their proper context. The
           model must consider the specific characteristics of the flooded area (which are
           seldom included), and its type of links with the affected population. Finally,
           the scheme must carry out an analysis in a more complex field than that of the
           usual socioeconomic descriptions. Actually, sudden relocation basically affects
           the population living strategies that include a number of relationships -- e.g.,
           economic cooperation, neighboring links -- the modification of which gives rise
           to the main social and economic cost that we are trying to reduce.

               Defining this theoretical scheme is necessary for creating living strategies
           that are equivalent to the present ones, so as to satisfy the needs of the
           transplanted population.   This "equivalent reposition" not only refers to the
           replacement of affected dwellings and goods but also to the possibility of
           obtaining work and earnings.


           UNIVERSE OF ANALYSIS

               According to the previous scheme, we define as "universe under study" the
           population whose link to the area represents a significant component to its
           living strategies.  That is, not only are the residents in the area included,
           but also the nonresidents who maintain ties (of labor, patrimony, etc.) with that
           area, developing in this way some aspect of their overall living strategy. Then,
           the main question is, Which are the modalities of that link between the
           population and the affected area? These relations occur at different dimensions
           (demographic, social, cultural, and economic) and result from the particular
           historic development of the area, from its cultural reality, from its regional
           economic institutions, and from its physical features (COMIP, 1984). It is also
           necessary to analyze the compulsory vs. uncompulsory character of that link.
           Among all the possible modalities, the most essential is that of the compulsory
           link on an economic basis. This category includes the economic activities that
           require the concurrence of some of the features of the area, such as obtaining
           the area's raw materials (ichthyic fauna, soil materials, etc.) and food
           (fishing), using its water for transport, using the area's coastal features or
           its proximity to urban centers and ports for supplies and services, and using
           its resorts for recreational activities and its land for production or dwelling.
           The uncomgulsory link, which can be easily reproduced in another area, will
           include agricultural activities that are not inherent to the area, industrial
           and commercial activities that do not require the area's raw materials, community
           servi ces (heal th, educati on, dwel I i ng, etc. ) , and the f ami 1 i ar or commun i ty 1 i nks
           (cultural, religious, political, ethnic, etc.).


           LIVING AND/OR SURVIVAL STRATEGIES

                In developing relocation strategies, we are not dealing with good or bad
           players who follow strategies either to win or to lose. Rather, we are concerned
           with human beings who are doing their best to survive (Bartolome, 1983). Also,
           the unit of analysis is not the individual, but rather the family, since people
           organize themselves in families so as to face the problem of living.


                                                 423








              Central and South America

                   First of all, the survival strategies concept is used to study the
              implications between the population factors (fertility, and familiar structures
              and types) and a community's economic structure (productive patterns, labor
              markets, etc.).    Later on, the concept is enlarged to include politics and
              organizing behavior, provided the basic needs are satisfied not only in the area
              of economics but also the areas of the society and politics.        First, of the
              strategies the poor social groups or sectors were analyzed.        Then, with the
              prompt diffusion of the concept, the middle and even the most privileged layers
              of society were investigated.     This approach allowed for the literature to
              include generic definitions as well as more restricted and specific formulations.

                   As an example of the first type, it is worth mentioning the definition that
              describes the survival strategies "as the attitudes or arrangements that take
              place in the family to face the problem of existence or living, which in many
              cases does not surpass the survival level" (Rodriguez, 1981). Consequently, any
              type of family belonging to any social group or stratum can be the subject of
              a strategy. Because of this definition, the living strategies notion has been
              adopted.

                   In contrast, among other authors who use restricted formulations are Duque-
              Pastrana (1973), who introduced this concept to the social sciences. They have
              sustained that in order to ensure the family income, the survival strategies
              must delineate the economic roles of every member of the family, even extended
              family members. From this point of view, the subjects are exclusively families
              belonging to the impoverished sector of society, and the strategies are only of
              an economic sort. Aside from their discrepancies, the different approaches have
              overlapped on the following items:

                      the unit of analysis is the family instead of the individual;
                      the survival or living strategies vary according to social strata; and
                      the strategies are subjected to the prevailing "economic structure."

                   In this work we will define the "living strategies" concept as the modality
              in which the unit organizes itself and makes use of its resources to reproduce
              and/or optimize its material and nonmaterial conditions of existence; "survival
              strategies" has a corollary definition, applied to the poorest social strata.
              This definition is chosen because the problem of relocation involves all the
              social sectors of the area to be flooded and these people are affected not only
              economically but also socially, demographically, and culturally.

                  Groups who develop the living strategies consist of individuals who are
              linked to one another by bonds that admit a common past and that jointly project
              toward the future. The living strategy they use assigns the participatory roles
              to each member of the group. The strongest group is the family, the fundamental
              unit of analysis. We define this group as people whose association is based on
              sharing a residence; being linked by blood or marriage; interacting daily,
              regularly, and permanently; and tending jointly to the reproduction and/or
              optimization of their material and nonmaterial conditions of existence.





                                                     424









                                                                                          Massei

           THE ENDOGENOUS CONPONENTS OF THE STRATEGIES

                 Because of the complexity of the problem of relocating, it is not easy to
           delimit precisely the components of the living strategies, at least at the level
           of those categories and variables that constitute them. Nevertheless, advances
           provided by the specialized literature define a basic group of aspects or
           dimensions of them that can be arranged according to different fields in which
           they appear.

                 For example, in the socioeconomic field, the relevant elements are connected
           with activities that involve obtaining goods and services to fulfill the unit's
           basic needs. They include ways of being part of the productive structure, such
           as in the employment arena; how the work is organized within the unit; ways and
           sources for consuming goods and services; the network of interchanging goods and
           services; and the network of mutual aid or extrafamiliar cooperation.

                 In the cultural field, special relevance is acquired by the values and the
           rules put into practice in the acquisition and preservation of goods and services
           (e.g., attitudes toward the role of women).          These habits, attitudes, and
           behavior are passed on through social inheritance (Bartolome, 1983). In fact,
           they become such a part of the culture that they can obstruct the possibility
           of improvement of the survival condition (Arguello, 1981).

                 The demographic field includes the considerations of the structure of the
           units and their characterization in terms of sex, age, fertility, construction
           ways of unions, mortality, migrations (especially those of a labor sort), the
           familiar living cycle stages (initial, expansion, and fission), duration of said
           stages, etc. These aspects are important to plan resettlement policies that may
           take into account the family requirements in the long run.

                 Many variables have ambiguous implications according to the context in
           which they appear. For example, in the demographic factors case, theJact that
           a farming couple has many children could be considered as a survival strategy,
           based on the reasoning that the more children they have, the more manpower they
           can count on, and consequently the better resources they can have to fulfill
           their needs. However, the large number of offspring can be a burden and, as a
           result, a conditioning could occur that could influence negatively, because they
           are in the family cycle's first stages and they have scarce productive resources.


           CONTEXTUAL FACTORS

                 Table 1 lists a number of contextual factors that must be taken into account
           for an exhaustive understanding of the strategies.

           Local Level

                 The local level or the immediate social environment is where we find the
           articulation of relationship or neighboring links that form the basis of
           sociocultural identities and informal economic relations. In many cases, these
           links contribute more to the support of the family than the monetary or formal
           income.   To know these links is very important because, apart from having an

                                                    425








             Central and South America

                   Table 1. Factors That Should Be Considered in Evaluating Relocation


                          Contextual factors             Endogenous characteristics


                          - Access to the land                  -Demographic
                          - Social organization                 -Migratory
                          - Work market                         -Occupational
                          - Productive organization             -Educational
                          - Goods market                        -Sociocultural
                          - Goods and services offered          -Consumption
                          - Public policies
                          - Development projects

             Source: COMIP - Precensus Tasks (1985).


             effect on the strategies, they determine   the behavior of population in social
             processes, such as resettlement.

             Regional/Subregional Level

                   This leads to a careful consideration of the surrounding regions or
             subregions and of the area's interactions with them, even beyond the frontiers
             among countries, surpassing the reductions to both the ecological and the
             political administrative aspects.   It is at this level where we will detect, on
             the one hand, the structure of production and employment and, on the other hand,
             the mechanisms to obtain goods and services through the so-called "needs
             fulfillment circuits." The analysis of these circuits allows us to know the type
             of needs to be fulfilled, to what extent they are fulfilled (especially the basic
             needs), the area (space) where the goods and services are acquired, and the way
             of approaching them.

             National Level

                   The national level determines the historic and cultural context of
             development.   It is also at the national level where it would appear to be
             convenient to evaluate the public policies that could affect the living
             strategies and, above all, the scope and covering of the actions arising from
             such policies in the regional field of the affected area, provided that process
            .will affect said field.



             PROOF OF CONSISTENCY

                   A specific census was carried out according to this conceptual scheme for
             the relocation policy of an Argent i ne- Paraguayan multipurpose hydroenergetic
             project in the Parana River, Corpus Christi.       Contrary to the conventional
             census, it accounted for strategies, sociocultural components, and the formal
             and informal links that exist in the affected area, apart from the demographic
             and economic components.

                                                    426








                                                                                     Massei

               The same proof also verified the methodology's consistency and the
         relevance of the constitutive variables.      The typology elaborated on these
         variables and on the previous knowledge about the population. These variables
         appeared to be effectively discriminating, despite the fact that some "mixed"
         productive insertion strategies were detected together with the cyclic character
         of some of them, whiA revealed the necessity of incorporating the historic
         prospect to achieve their adequate characterization. The important fact here
         is that an exploratory proof has been carried out. This census does not rule
         out the necessity of using other types of instruments and careful studies to
         become more knowledgeable as regards cultural rules and values and the circuits
         that lead us to fulfill the needs of people being relocated.


         CONCLUSIONS

               Resettlement is not simply physical evacuation, but a complex social
         process. The following criteria are essential to a successful resettlement:

               1. To fix as an aim of the policy that the whole of the affected population
                   could reconstruct its living strategies, generally improving its
                   conditions of existence. This reconstitution would consist of:

                   ï¿½  keeping or substituting its resources and their optimization
                      modalities;

                   ï¿½  keeping its social articulations and the cultural components of its
                      lifestyle;

                   ï¿½  introducing in its strategies changes positively valued by the people
                      in terms of their life projects; and

                   ï¿½  obtaining the recognition of the involved actors that the subject
                      of this process is the population at an individual level as well as
                      under the different associative forms.      Involved actors include
                      agency, the affected people, and the authorities.

               2.  To define as policy subjects all those who might be linked to the
                   affected area and whose link might constitute a significant component
                   of their living strategy (residents or nonresidents).

               3.  To define the living strategies as an affected object, because the
                   disruption between the units and the particular field where they develop
                   basically affects them.    Consequently, they also appear to be the
                   replacement object -- that is to say, what the relocation policy must
                   restore to the population.    This strategy's reconstruction will not
                   imply a mechanical transposition, but rather a functional replacement
                   equal to the economic and social conditions that are necessary to carry
                   out the strategies. This implies that other aspects, positively valued
                   by the people, could be generated functioning as alternatives of those
                   that cannot be reconstructed.




                                                427








              Central and South America

                     4.  It is not likely that the replacement can be carried out at comparable
                         levels, especially for those sectors whose conditions of existence are
                         definitely inferior to the socially accepted minimum standards of
                         existence.    As a result, we will aim to generally improve those
                         conditions.

                     5.  To encourage the people's participation in relocation decisions, both
                         direct and channeled through the different associative forms (either
                         formal or informal). The policy's formulation and its application will
                         grow out of that participation, positive modalities valued by the
                         affected people, and from specific modalities for each social sector.

                     6.  To set the relocation units on two levels:       one based on family, and
                         the other based on customs for the preservation of links and networks
                         among units.

                     7.  To contemplate the reconstruction of the community's structure, and
                         the integration of the relocated people among each other and with the
                         receiving population.

                     8.  To aim at establishing the new settlements in places as near as possible
                         to the former location, so as to maintain most of the preexisting links
                         and to count on circuits to obtain resources and to fulfill needs
                         already proved and recognized.

                     9.  To include all the aspects -- social, economic, judicio-legal,
                         technical, etc. -- to guarantee the integral management of such
                         resettlement.



              BIBLIOGRAPHY

              Arguello, 0. 1981. Estrategias de supervivencia: un concepto en busca de su
              contenido. Economia y Demografia XV. Buenos Aires.

              Bartolome, L.J.     Estrategias adaptativas de los pobres urbanos:        El elemento
              entropico de la  relocalizacion compulsiva. Entidad Binacional Yacyreta y Depto.
              de Antropologia, Social, Universidad Nacional de Misiones, Argentina.

              Bartolome, L.J.    1983. Aspectos sociales de la relocalizacion de la poblacion
              afectada por la   construccion de grandes presas. UN-OEA. Buenos Aires.

              Borsotti, C.A.      La organization social de la reproduccion de los agentes
              sociales, las unidades familiares y sus estrategias.           Demografia. Economica.
              Mexico.

              Cernea, M.    1989.   Relocalizaciones involuntarias en proyectos de Desarrollo.
              Banco Mundial, Report No. 805, Washington.

              COMIP. 1984. Tareas precensales, primera etapa. Buenos Aires-Asuncion.

              COMIP. 1985. Tareas prcensales, segunda etapa. Buenos Aires-Asuncion.

                                                        428









                                                                                               Nassei


            COMIP. 1986. Formulation preliminar de al Politica de Relocalizacion. Buenos
            Aires-Asuncion.

            Duque-Pastrana, E.      1973.   Las estrategias de supervivencia economica de las
            unidades familiares del    sector popular urbano: una investigacion exploratoria.
            PROELCE. Chile.

            Jelin, E. 1983. Familia, unidad domestica y division del trabajo (que sabemos,
            hacia donde vamos). CEDES. 'Buenos Aires.

            Massei, C.     1983.   Methodologia general para el analisis socio-economico del
            emprendimiento en la zona de Corpus. Efectos sociales de las grandes presas de
            America Latina, Seminar. UN-OEA. Buenos Aires.

            Massei, C., and G. Borches. 1983. Evaluacion y planificacion regional de una
            obra publica de-propositos multiples de gran envergadura. Buenos Aires.

            Massei, C., and G. Borches.         1984.    Concepto de estrategias de vida y su
            inclusion en la elaboracion de politicas de relocalizacion, Seminar. UN-OEA.
            Posadas, Argentina.

            Partridge, W. 1983. Relocalizaciones en las distintas etapas de desarrollo de
            los emprendimientos hidroelectricos. UN-OEA. Buenos Aires.

            Rodriguez, D.       1981.    Discusion en torno al concepto de estrategias de
            supervivencial.      Relatorio del taller sobre estrategias de supervivencia.
            Demografia y Economica, Nro. 46. Mexico.
            Torrado, S. 1981. Sobre los conceptos de estrategias familiares de vida and
            proceso de reproduccion de al fuerza de trabajo: Notas teoricas-metodologicas."
            Demografia y Economica, Nro. 46. Mexico.

            Torrado, S.    1983. La familia como unidad de analisis en censos y encuestas de
            hogares. CEUR. Argentina.


















                                                      429























                    NORTH AMERICA










             RESPONDING TO GLOBAL WARMING ALONG THE U.S. COAST


                                          JAMES G. TITUS
                                   Office of Policy Analysis
                            U.S. Environmental Protection Agency
                                      Washington, DC 20460






           INTRODUCTION

               The process of responding to accelerated sea level rise in the United States
           is well under way,  at least for a phenomenon that is not expected for several
           decades. Over the  last seven years, almost all of the coastal states have held
           at least one major conference on the subject, and a few of them have altered
           coastal development policies to accommodate a future rise. Public officials are
           generally familiar with the issue, as are representatives of the press,
           nongovernmental organizations, and coastal investors. The federal government has
           conducted assessments of possible nationwide responses, and of implications for
           specific types of decisions, such as the design of coastal drainage systems,
           maintenance of recreational beaches, and protection of coastal wetlands.

               This paper examines possible responses to sea level rise in the United
           States. Because the most important question is what should we actually do in
           response to rising sea level, we focus primarily on the planning and engineering
           strategies that will determine how activities on the coast eventually change.
           Nevertheless, because the process by which society comes to understand the need
           for action is also important, we conclude with a brief summary of the evolution
           of U.S. sea level rise studies in the 1980s.



           FUTURE RESPONSES: SHORELINE RETREAT AND FLOODING

               The most important responses to sea level rise in the United States can be
           broadly classified as responses to shoreline retreat, increased flooding, and
           saltwater intrusion.    In each case, the fundamental question is whether to
           retreat or to hold back the sea.

               Shoreline retreat has received by far the greatest attention; nevertheless,
           because flooding involves the same strategic questions, we combine the
           discussion. Because there is a general consensus in the United States to "let
           nature take its   course" in national parks and other undeveloped areas, we
           examine only developed areas. We divide our discussion of this impact into two


                                                 433








             North America

             parts: barrier islands and the open coast, and sheltered areas. We conclude the
             section by discussing when action is likely to be necessary.

             Barrier Islands and the Open Coast

                  Oceanfront communities could respond to sea level rise by protecting
             developed areas with dikes, pumping sand onto beaches and other low areas, or
             retreating from the shore.     Along mainland beaches, the last option generally
             implies no coastal protection; in barrier islands, however, it would also be
             possible to engineer a landward retreat of the entire island, creating new land
             on the bayside to offset that lost to oceanside erosion. The four options are
             illustrated in Figure 1.

                  To obtain a rough understanding of the relative costs of these options, we
             examined Long Beach Island -- a long, narrow barrier island developed with
             single-family homes and one- and two-story businesses (see Figure 2). Table 1



             Table 1.     Cost of Sea Level Rise for Four Alternative Options for Long Beach
                      Island, New Jersey (millions of U.S. dollars)

             Sea level           Levee with          Raise        Island                 No
               rise                beach             island       retreat            protection
               (cm)


                                                  Total Cost

                 30                  52               105             41                    55
                 60                434                285            109                        462
                 90                509                522            178                        843
               120                 584                786            247                 1548
               150                 659               1048            308                 1740
               180                 734               1310            371                 1932
               210                 809               1574            431              total loss
               240                 884               1835            492              total loss

                                               Incremental Cost

                               Levee     Sand

               30                0       52          105              41                    55
               60               330      52          180              68                  407
               90                0       75          237              69                  381
              120                0       75          264              69                  705
              150                0      103          262              61                  190
              180                0      103          262              61              total loss
              210                0      110          262              61              total loss
              240                0      110          258              61              total loss

             Source: Weggel et al.     (1989) (dike  cost); Yohe (1989) (no protection).

                                                      434








                                                                                          Titus



                            Initial CaSe

                            --%VWMft'







                            No Protection


                            -------                           -------------------








                            Engineered Retreat




                                                              -------------------








                            Island Raisina



                                 - - -                        - - - - - - - - - - - - - -








                            Levee



                                                                ------------------






          Figure 1. Responses to sea level rise for developed barrier islands.


          illustrates the costs of the four options for a rise in sea level between 30 and
          240 cm. For a rise greater than 50 cm, any of the protection options would be
          less expensive than allowing the sea to reclaim the valuable resort property.
          Although surrounding the entire island with a dike would be less expensive than
          raising the island, it would be culturally unacceptable because             it would
                                 @,ed Retea,




                            @_ev e






          interfere with access to the beach, and people would lose their views of    the bay.

                Engineering a retreat would also be much less expensive than raising the
          island in place, because the latter option would require more (and higher


                                                   435








                                                                North America




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    ............


                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ...........
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      ....................
                                                                                                                                                                                                                                                                                                                                                                                                                                                                       ....................
                                                                                                                                                                                            Vetlands
                                                                                                                                                                                                                                                                                                                     Wetlands
                                   ...........
                                                                             . . .. .......



                                                                                                                                                                                                                                                                                                                                                                                                                                                              ..........
                                                                                                                                                                                                         @j               j                                                                                                                                                                                                                                   ..........
                                                                                                                                                                                                                                                                                                                                                                              -4
                                                                                                                                                                                                                                                                                                                                                                                                                                                                         ..........


                                                                                                                                                                                                                                                                                .....      .......

                                                                                                                                                                                                                                                                                                                                                                                                        ... ..........
                                                                                                                                                                                                                                                                             ......                                                                                                                           ..........
                                                                                                                                                                                                                                                                                                                                                                                                        ............
                                                                                                                                                                                                                                                                                                                                                                                                        .... ...........
                                                                                                                                                                                                                                                                                                                                                                                ..........
                                                                                                                                                                                                                                                                                                                                                                              ...............
                                                                                                                                                                                                                                                                          ........                                                                                               ...........
                                                                                                                                                  .....                                                                                                                                                                                                                                                 ... .......

                                                                                                                                                                                                                                                                                                                                                                                                                                                                 ............
                                                                                                                                                                                                                                                                                                                                                        ....                                                                                                        ......


                                                                                                                                                                                                                                                                                                                            ...........................
                                                                                                              ............... ..........                             .....
                                                                                                                                                                                                                                                                                                                          .........................                                                                                            ......         ... ....
                                                                                                                                                                                                                                                                                                               .. ............
                                                                                                                                                                                                                                                                                                                                                                                                                                              . ....          .....                    ....
                                                                                                                                                                                                                                                                                                                         .............

                                                                                                                                                                                                                                                                                                                                                                                        ........ ..
                                                                                                                           . ...........                          .. L                                                                                                                                                                                                     . . . . ......                                                                                        ..............

                                                                                                                                                                                                                                                                                    ...........                                                                                                                                                               ..........................
                                   ..........
                                                                                                                                                                                                                                                                     ........           ........... . .                                                                                                                                                                     .................
                                                                                                                                                                                                                                                                                                                                                                                        ...........
                                                                                                                                                                                                                                                                                                                                                                                        ...........
                                                                                                                                                                                                                                                                       A          I                                                                                                     .............
                                   ..................                                                         ....... ... ..                                 ................           -
                                                                                                          . ...........                                      .......
                                                       i@ Nil
                                                                                                                                                                                                                                                                                           . . ....                                                                                                     ....
                                                                                                                                                                                       ..................
                                                                                                          . . .........
                                                                                                          ...............
                                                                                                          .. . ..........
                                                                                                                                                                                                  ...........
                                                                RKIMM        ......
                                   ................
                                                   ....                                         ... ....................                                                                                                                                                                             ......
                                                                                                                                                                                                                                                                               ............         ....                                                                                ...........
                                                                                                                                                                                                                                                                                        ............
                                                                                                                                                                                         ... ..                                                                                                        ....                                                                                             ...
                                                                                                                                                                                      .. . ..........
                                                                                          ..........                                                                                    .................
                                                                                                                                               .... .            .....
                                                                ........                                  .... .           .....
                                                                                                          ..........
                                   ...                          .......                                                                                                                           .......
                                                                ..............                            ...... ..               ..
                                                                ...............                           .......          .. .
                                                                ...............                           ....I    ......
                                                                ........ . ..                             ........ .
                                                                ..............                            ....     ... .
                                                                .........    --           . ..... ................                                                                                                                                                                             ..........                                                                                               ...
                                   ...                          .............. ..........                                                                                                 .................
                                                                                                                                                                                                                                                                                                                                                                                                        x. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .
                                                                                                                                                                                                                                                                                                                                                                                                                                          ... .......
                                                    ..... . . . . . . . . . . . . . . . . .               . . . . . . . . . . . . .                                                                                                                                                                                                                                                     . . . . . . . . . .. . . . . . .
                                                                .. . . . . . . .. . . . . . .
                                                        . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .
                                                  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .



                                                                                          - - - - - - - - - - -                      - - - - - - - -----
                                                                                                                           . . . . . . . . . . . . .
                                                                                                                                  X. :K-';Kg - : --K.



                                                                                                                                                                                            R, -k:






                                                                                                                                                                                                               OK
                                                                                                                                                                                         .........
                                                                                          Jersey                                                                                  -M,

                                                                                                                                               jM
                                                                                                                                                                  ew Yor"                                                                   A
                                                                                          'nk




                                                  ZK-X@





                                                                                                                                                                                                                                                                                                 A
                                                                                                                                                             Long Beach
                                                                                                                                                             Island


                                                                                                          r,;@             'Atiantlc City                                                                                                                                                                                              @7-

                                   ZZ:'.. kk









                                                                Figure 2. Long Beach Island, New Jersey.

                                                                                                                                                                                                                                                           436











                                                                                                  Titus

           quality) sand.       However, this option would be vigorously opposed by the
           oceanfront owners who would have to move their houses to the bay side, as well
           as by bayfront owners who might lose their access to the water.                   Moreover,
           filling new bayside land would disrupt back-bay ecosystems unless the estuary
           were also allowed to migrate landward onto the mainland (which we discuss below).
           As Table 2 shows, island raising would cost less than $600 per house per year
           (U.S. dollars) until after sea level had risen more than 60 cm; this would be
           less than the rent for one week. Thus, we suspect that the more expensive but
           less disruptive approach of pumping sand onto beaches and the low bay sides of
           barrier islands would be the most commonplace, at least in the beginning.

                  Table 3 compares the ability of the four options to satisfy various
           desirable criteria. (Most of the rationale for this table is found in Titus,
           1990.) An important lesson from the Long Beach Island study is that the least
           expensive solutions are not always the most likely; dikes are culturally
           unacceptable,     and an engineered retreat           is administratively difficult.
           Nevertheless, the noneconomic criteria should not always outweigh economics.

                  Leatherman (1989) estimated the quantity of sand necessary to hold back the
           sea for every coastal state but Alaska, and estimated the cost assuming that sand
           does not become more expensive.            Titus et al . (1990) adjusted those cost
           estimates on the assumption that as least-cost supplies are exhausted, it will



           Table 2.      Evolution Over Time of the Relative Costs of Retreat Island Raising
                          (Long Beach Island, New Jersey)


           Sea level                        Years before Cost (millions) Cost (U.S. $/Yr/housel
           above 1986                       sea will                   Raise                  Raise
              (cm)              Year*       rise  15  cm      Retreat island     Retreat       island


              15                2013              18           20        57           77        219
              30                2031              14           34        85         168         420
              45                2045              12           34        95         196         548
              60                2057              11           34      110          214         692
              75                2068              10           34      127          235         879
              90                2078               9           34      132          261        1015
              105               2087               9           34      132          261        1015
              120               2096               8           34      132          294        1142
              150               2112               7           30      132          296        1305
              180               2126              6.5          30      132          319        1406
              210               2139               6           30      132          346        1523

               Assuming global sea    level rises one meter by the year 2100.
           NOTE:    All costs assume that until the particular year, the community has
           responded to sea level rise by raising the island in place.
           Source: Titus (1990)

                                                       437











               North America

               Table 3. Ability of Alternative Responses to Satisfy Desirable Criteria, Long
                         Beach Island, New Jersey (assuming 1 m rise by 2100)


                Policy:                  Dikes     Raise       Engineered           Abandonment
                                         Islands Retreat                         Forced    Unplanned

               Criteria

               Social Cost
                  Cumulative             584           786     247                 1548       1548
                  ($millions)
                  Present Value
                  ($millions, 3%)        115           130     46                  170        170

               Environmentally           No        Usually     Usually              Yes        Yes
                Acceptable
               Culturally                No        Yes         Yes                  No       Maybe
                Acceptable

               Legal                     Yes       Yes         Maybe               Maybe      Yes

               Constitutional            Yes       Yes         Yes                 Maybe      Yes

               Institutionally           Yes       Yes         Maybe               Maybe      Yes
                Feasible

               Performs Under            Poor      Good        Good                Good       Good
                Uncertainty

               Immmune to                Yes       Mostly      Somewhat             No        Mostly
                Backsliding

               Source: Titus (1990).


               be necessary to go farther out to sea for suitable sand. Table 4 'illustrates the
               resulting estimates of dredging costs for current trends and rises in sea level
               of 50, 100, and 200 cm.     Titus et    al. also estimated the cost of elevating
               buildings and utilities as sea level    rises.

                    These calculations are only        rough estimates.       Leatherman probably
               underestimated total sand requirements by assuming that beaches would be designed
               only for a one-year storm; designing them for a 100-year storm would increase the
               cost by 50-100 percent. Moreover, Titus et al. ignored the cost of elevating
               multifamily buildings, and sea level rise would be factored into               routine
               reconstruction of water and sewer liines at no incremental cost. On the other
               hand, our calculations assume that all        developed areas will be protected.
               Although this is a reasonable assumption for Long Beach Island and similar areas,
               it would be less expensive to abandon more lightly developed islands. Moreover,

                                                       438











                                                                                          Titus

                Table 4.    Nationwide Impact of Sea Level Rise on the United States


               Trend                          50 cm            100 cm             200 cm

          If No Shores Are Protected

          Dryland lost (sq mi)            3,315-7,311        5,123-10,330       8,191-15,394
          Wetlands lost (%)                   17-43             26-66              29-76

          If Developed Areas Are Protected

          Dryland lost (sq mi)            2,200-6,100        4,100-9,200        6,400-13,500
          Wetlands lost (%)                   20-45             29-69              33-80
          Cost of coastal defense
          (billions of 1988 dollars):         32-43             73-111             169-309
            Open coast:
              Sand                            15-20             27-41              58-100
              Elevate structures                9-13            21-57              75-115
            Sheltered shores                    5-13            11-33              30-101

          If All Shores Are Protected

          Wetlands lost (%)                   38-61             50-82              66-90

          Source: Titus et   al. (1989).


          a number of states have already required construction to be set back from
          theshore a few hundred meters, suggesting that no protection would be required
          for the first 50 cm of sea level rise.

          Sheltered Waters

                Americans' affinity for beaches and concern for the environment have
          created a strong constituency against holding back the sea with dikes and
          seawalls, counterbalancing the natural tendency of all landowners to protect
          their property.    Along the open coast, both interests can be accommodated,
          because beach nourishment protects property by maintaining the natural
          shoreline.    Along sheltered waters, however, the prospects for avoiding a
          conflict are not as great. As Figure 3 shows, protecting property with dikes and
          bulkheads would prevent wetlands from migrating inland and could eventually
          result in their complete loss in some places.

                In a recent EPA report to Congress on the implications of global warming,
          Park et al. (1989) examined the potential loss of wetlands and dryland for a
          sample of 46 sites comprising 10 percent of the U.S. coastal zone, for three
          alternative responses:      no protection, protecting areas that are densely
          developed today with dikes and bulkheads, and protecting all shores.       For each
          site, Weggel et al. (1989) estimated the cost of protecting developed areas from

                                                   439










                      North America







                                              5000 YEARS AGO                                                           TODAY




                                                                     SEA LEVEL                                                                    CURRENT
                                                                                                                                                  SEA LEVEL
                                                                                       SEDIMENTATION AND                                          PAST
                                                                                       PEAT FORMATION                                             SEA LEVEL



                                                                             FUTURE

                                                                                                    COMPLETE WETLAND LOSS WHERE HOUSE IS PROTECTED
                    SUBSTANTIAL WETLAND LOSS WHERE THERE IS VACANT UPLAND                           IN RESPONSE TO RISE IN SEA LEVEL


                                                                         FUTURE                                                                  FUTURE
                                                                         SEA LEVEL                                                              SEA LEVEL
                                                                         CURRENT
                                                                         SEA LEVEL                                 P.. ----------CURRENT
                                                                                                                   N.;                          SEA LEVEL



                             PEAT ACCUMULATION




                      Figure 3. Evolution of a marsh as sea level rises (Titus, 1986).


                      a 2-meter rise. Titus et al. (1990) used cost functions suggested by Weggel et
                      al. and estimates of inundated land from Park et al. to interpolate the cost
                      estimates, and developed confidence intervals for the estimates of lost land.

                               Table 4 illustrates the nationwide results (the source studies provide
                      regional detail). For a one-meter rise, the cost of protecting the most densely
                      developed 1,000 square miles of coastal lowlands would work out to $3,000 per
                      acre per year, which would generally warrant protection.                                                  However, such
                      protection would increase the loss of wetlands by 300-500 square miles, and would
                      reduce the area of shallow water for submerged vegetation by another 500-700
                      square miles. Moreover, many vacant areas are being rapidly developed. If all
                      areas must be protected, the additional loss of wetlands would be 1,800-2,700
                      square miles, and another 3,000-7,000 square miles of shallow waters would be
                      lost.

                               The political process will have to decide whether to abandon coastal
                      lowlands to protect the environment. To help the necessary discussions get under
                      way we are circulating a draft that investigates seven options for enabling
                      coastal wetlands to migrate landward (Titus, 1989). The first two apply only to
                      undeveloped areas: prohibiting development and purchasing coastal lowlands. The
                      next three involve doing nothing today and purchasing land and structures when

                                                                                    440











                                                                                         Titus

          inundation is imminent; forcing people to move out when inundation is imminent;
          or hoping that protection will prove to be uneconomic. The final two options,
          which we call "presumed mobility," allow people to use their property as they
          choose, but on the conoition that they eventually will abandon it if and when sea
          level rise threatens it with inundation; presumed mobility could be implemented,
          whether by prohibiting construction of bulkheads and levees or by converting
          property ownership to long-term or conditional leases that expire when sea level
          rises a particular amount.

                Table 5 summarizes our assessment of each option to satisfy various
          desirable criteria, including low social cost, low cost to taxpayers, performance
          under uncertainty, equity, constitutionality, political feasibility, and the risk
          of backsliding.   Unlike the table for barrier islands, we omit environmental
          criteria because each of these options is each designed to achieve roughly the
          same level of environmental protection.

                Our overall assessment is that presumed mobility would be the best general
          approach.   A general prohibition of development would probably violate the
          takings clause of the Bill of Rights; buying 20,000 square kilometers of land
          would be expensive, and in any event, these options apply only to areas that have
          not yet been developed. Doing nothing today seems unlikely to protect wetlands
          because (1) purchasing property in the future would be even more expensive if it
          is developed; (2) forcing people to move out of their homes would be
          politically impossible if they are willing to tax themselves to pay for the
          necessary protection; and (3) economics alone is unlikely to motivate people to
          abandon developed areas.

                One of the most overlooked but important criteria is performance under
          uncertainty. No one knows how much sea level will rise in the future; only rough
          estimates are available. Thus, policies likely to succeed for a rise anywhere
          between 0 and 3 meters should be preferred over those that might be superior for
          a particular scenario but might fail if other scenarios unfold.           For this
          criterion, the approach of presumed mobility is clearly superior: ecosystems will
          be protected no matter how much sea level rises; real estate markets will be able
          to efficiently incorporate new information on sea level trends; and if the sea
          does not rise significantly, the policy costs nothing.        By contrast, buying
          coastal lowlands or prohibiting development requires policy makers to draw a
          (disputable) line on a map above which the policy does not apply.     If sea level
          rises more than assumed, ecosystems eventually will be lost; if it rises less,
          society will have unnecessarily forfeited the use of valuable coastal land.

          When Will a Response Be Necessary?

                A recent study by the National Research Council (Dean et al., 1987)
          concluded that because dikes can be erected in a relatively short period of time,
          no action is necessary today. This argument also applies for beach nourishment
          on the open coast. However, our analysis of wetland-protection options suggests




                                                  441









        Table 5. Alternative Strategies for Protecting Natural Shorelines: Areas That Have Not Yet Been Developed


                                                 Social Cost                                Performance under       Consti-              Political                    New
                         Cost               (vs. no sea Level, rise)          Economic        uncertainty:         tutionat              fessi-      Risk of     institutional        Likelihood of
        Policy              to public          Present value      CumuLative       Efficiency    See Level Economics               Equitable     bitity backsliding        requirements        success


        1. Prohibit    None              speculative         Land                Poor       No            Yes          No      No           None     Possible      Regulatory         Almost certain
            Deve I opment                premium +0%                                                                                                                                  at first, un-
                                         of base value                                                                                                                                likely in Long
                                                                                                                                                                                      run

        2. Buy         Speculative       Speculative         Land                Poor       No            Yes           Yes    Yes          None     Possible      Park Service       Almost certain
            coastal    premium           premium + 0%                                                                                                              aquisition         at first,
            Lard                         of base value                                                                                                                                unlikely in
                                                                                                                                                                                      tong run
        Defer Acti
        3.  order      None              0% of land          Land and            Fair       Yes           Perhaps    Maybe     Doubtful     Low      Very          Police             Unlikely
            people out                   and structures      structures                                                                              likely
            later
        4.  Buy        land and          0% of Land          Land and            Fair       Yes           No         Yes       Yes          Low      Very          Park Service
            out Later  structures        and structures      structures                                                                              Likely        Aquisition         Unlikely


        S.  Rely on    None              0% of land          Land and            Fair       Yes           Useless    Yes       Yes          Good     Low           Hazard             Unlikely
            elements/                    and structures      structures          (if it                                                                            Mitigation
            economics                                                            works)


        Presumed mobility
        6. No          None              0% of IBM           Land + residual     optimal    Yes           Yes        Probably               Good     Likely        Regulatory         Very Likely
            bulkheads                    value               value of                                                          usually
                                                             structures


        7. Leases      0% of Land &      <1% of land         Land + residual     Optimal    Yes           Yes        Yes       Yes          fair     Very          Change in          Almost
                       residual value    value               value of                                                                                unlikely      titles of          certain


         .0b
         4b












                                                                                               Titus

           that these measures are likely to be effective only if they are implemented
           several decades in advance: people would need several decades to depreciate
           structures and to become accustomed to      the idea that property must be abandoned
           to the sea to protect the environment.

                  A number of planning mechanisms are in place along the ocean coast to
           foster a retreat. North Carolina and a      number of other states require houses to
           be set a few hundred meters back from       the beach and prohibit hard engineering
           structures along the beach.          South Carolina prohibits reconstruction of
           storm-damaged property if such property is too close to the shore.

                  Along wetland shores, however, only Maine has implemented planning measures
           to allow ecosystems to migrate inland. That state has explicitly incorporated
           presumed mobility into its development regulations, which state that structures
           are presumed to be movable; in the case of apartments that are clearly not
           movable, the regulations state that if the buildings would block the landward
           migration of wetlands and dunes resulting from a one-meter rise in sea level, the
           developer must supply the state with a demolition plan. Although other states
           require construction to be set back somewhat from the wetlands, the setbacks are
           small compared with the inland migration of wetlands that would accompany a one-
           meter rise in sea level.



           FUTURE RESPONSES: MISSISSIPPI DELTA

                  Louisiana is currently losing over 100 square kilometers of land per year
           because human activities are thwarting the processes that once enabled the
           Mississippi Delta to expand into the Gulf of Mexico. For thousands of years, the
           annual river flooding would deposit enough sediment to enable the delta to more
           than keep pace with sea level rise and its own tendency to subside.         In the last
           century, however, the federal government has built dikes along the river and has
           sealed off "distributaries" to prevent flooding and to maintain a sufficiently
           rapid riverflow to prevent sedimentation in the shipping lanes.            As a result,
           sediment and nutrients from the river no longer reach most of the wetlands, and
           they are being rapidly submerged. Moreover, with flows in distributaries cut
           off, saltwater is penetrating inland, converting cypress swamps to open water
           lakes and otherwise disrupting wetlands.         If sea level rise accelerates, the
           already rapid disintegration of coastal Louisiana would follow suit.

                  As with other coastal areas, both dikes and abandonment are possible.
           However, there is a general consensus that these options should be avoided if
           possible, because in either event, most of the delta's wetlands would be lost,
           and those wetlands support 50 percent of the nation's shellfish and 25 percent
           of its fish catch. Thus, federal and state officials are focusing primarily on
           options to restore natural processes that would enable at least a large fraction
           of the del ta to survi ve even an accel erated ri se i n sea I evel . The U. S. Congress
           has authorized a number of projects to divert freshwater and sediment to wetlands
           by effectively cutting holes in the dikes. Under current policies, however, such
           projects will likely divert only a small fraction of the river water to avoid
           siltation of shipping lanes.

                                                      443










            North America

                   In the long run, protecting Louisiana's wetlands would require people to
            allow the vast majority of the river's discharge to reac      'h the wetlands.    This
            would be possible if navigation were separated from the streamflow of the river.
            One way to do this would be to construct a series of canals with locks.between
            New Orleans and the Gulf of Mexico, and to completely restore the natural flow
            of water to the delta below the canal. Unfortunately, re@quiring ships to pass
            through locks would hurt the economic viability of the Port of New Orleans.
            Another option would be to build a new deep-water port 10-20 miles to the east.

                   Perhaps the far-reaching response, one that has been advocated by the
            state's Secretary for Environmental Protection, would be to allow the river to
            change course and flow down the Atchafalaya River. Without a $1 billion river
            control structure, the river would already have done so., Al.though from a purely
            environmental perspective this option is most appea         'ling, 'it wbuld further
            accelerate the loss of wetlands in the eastern part of the state and would enable
            saltwater to back up to New Orleans, requiring the city to find a new water
            supply.

                   It is somewhat ironic that human activities designed to prevent flooding
            may leave the entire area permanently below sea level in the long run. There may
            be a lesson for Bangladesh and other nations who are considering flood-protection
            dikes to protect land from surges in river levels:         build dikes around a few
            cities, but make sure the river is still able to flood enough areas for the flow
            of water to slow sufficiently to deposit sediment onto farmland and wetlands,
            rather than washing sediment out to sea where it will benefit no one.


            FUTURE RESPONSE: SALTWATER    INTRUSION

                   Responses to saltwater intrusion, like shoreline    retreat and flooding, can
            involve either holding back the sea or adapting to a landward encroachment.
            Preventing Salinity Increases

                   Figures 4 and 5 illustrate why sea level rise      increases the salinity of
            estuaries and aquifers, respectively. In the former       case, a rise in sea level
            increases the cross-sectional area of the estuary, slowing the average flow of
            water to the sea, the major process that keeps the estuary from having the same
            salinity as the ocean. Assuming that the tides continue to carry the same amount
            of water and that mixing stays constant, salinity will. increase because the force
            of freshwater is reduced while the saltwater force is, increased. Moreover, if
            the bay becomes wider, the tidal exchange of water will increase, further
            increasing the freshwater force.        (Because it is difficult to graphically
            represent the previous explanation, Figure 4 expresses it in a different fashion
            by comparing the amount of freshwater entering the estuary with the amount of
            seawater from the tides.)

                   Salinity increases can be prevented either by impeding the ability of
            saltwater to migrate upstream or by increasing the amount of freshwater entering
            the estuary. During the drought of 1988, the New Orleans District of the Corps
            of Engineers designed a barrier across the bottom of the Mississippi River that

                                                     444












                                                                                       Titus

          blocked saltwater on the bottom while allowing the ships and freshwater to pass
          on the top. In many cases where human withdrawals of freshwater have increased
          estuarine salinity 4nough to have adverse environmental consequences, water
          resource agencies have constructed projects to divert freshwater into estuaries.
          Elsewhere in Louisiana, the Corps has designed projects to divert water from the
          Mississippi River to wetlands that are suffering adverse effects of saltwater
          intrusion; and Everglades National Park has long had a similar arrangement with
          the Corps of Engineers and the South FLorida Water Management District.

               The Delaware River Basin Commission (DRBC) releases water from its system
          of reservoirs whenever salinity reaches undesirable levels, to protect
          Philadelphia's freshwater intake and aquifers in New Jersey that are recharged
          by the (usually) fresh part of the river. Hull and Tortoriello (1979) estimated
          that a 13-cm rise in sea level would require an increase in reservoir capacity
          of 57 million cubic meters (46,000 acre-feet), while Hull and Titus (1986)
          suggested that a 30-cm rise would require about 140 million cubic meters, about
          one-fourth the capacity that would be provided by the proposed Tocks Island
          reservoir.  Hull and Titus also noted that the DRBC has identified reservoir
          sites sufficient to offset salinity increases from sea level rise and economic


          Initial Condition













                                                    . . . . . . . . . . .
                                                                     EJ Freshwater

                                                                        Saltwater



          After Sea Level Rise

















          Figure 4. Increasing bay salinity due to sea level rise.

                                                 445










             North America
                            A

                                                                         Upper limit of
                                                                         water tabi



























                                Operating
                                Well

                                Abandoned
                                Well



















             Figure 5.   Impacts of sea level rise  on groundwater tables.   According to the
             Ghyben-Herzberg relation,  the freshwater/saltwater interface is 40 cm below sea
             level for every cm by which the top of the water table lies above sea level.
             When water tables are well below the surface, a rise in sea level simply raises
             the water table and the fresh/salt interface by an equal amount (A-B).       Where
             water tables are near the surface, however, drainage and evapotranspiration may
             prevent the water table from rising. In such a case (C), the freshwater table
             cour narrow greatly with a rise in sea level: for every I-cm rise in sea level,
             the fresh/salt interface would rise 41 cm.

                                                    446











                                                                                      Titus

        growth well into the 21st century. Williams (1989) conducted a similar analysis
        of the impacts of and responses to sea level rise in the Sacramento Delta in
        California.

              Although dams can be useful, one must understand their limitations. Most
        important, there is a finite amount of water flowing in the typical river; dams
        can increase the freshwater flow during the dry season because they reduce the
        flow during the wet season. Because droughts are generally the only time when
        high salinity is a concern, the impact on salinity during the wet season is
        generally not a problem.     Dams also reduce flooding, which (as we discussed
        above) can be viewed as a benefit by people who might otherwise lose property (or
        drown) in a flood; but this is a liability to the extent that flood prevention
        keeps sediment from reaching wetlands and enabling them to keep pace with sea
        level. A final problem is that if climate change makes droughts more severe in
        the future, it may be difficult to find sufficient reservoir capacity to offset
        the resulting reductions in riverflow, let alone increase riverflow enough to
        offset sea level rise. Salinity increases in aquifers can also be prevented by
        either increasing the force of freshwater or by decreasing the force of
        saltwater. The most notable application of the former approach is in southern
        Florida, where water managers maintain a series of freshwater canals whose
        primary purpose is to recharge the Biscayne Aquifer with freshwater. Various
        types of barriers have also been identified for blocking saltwater intruding into
        the estuary (Sorensen et al., 1984).

              Decreasing depletive uses of water can help to offset salinity increases.
        For example, during droughts the Delaware River Basin Commission has the power
        to curtail diversions of water to New York City. Reducing water consumption
        within the basin is a critical component of water management strategies in this
        and many other regions.

        Adapting to Salinity Increases

              If measures are not undertaken to prevent increase of salinity, people will
        have to adapt to it. Some cities could respond by moving their intakes upstream.
        Note that this appears to be the only response to increased salinity that would
        work with sea level rise but (at least in many cases) not with decreased
        riverflow. In the case of sea level rise, moving the uptake upstream the same
        distance as salinity advanced would leave the public (and if ecosystems were able
        to migrate upstream and inland, the environment) in roughly the same condition
        as before the sea level rose. By contrast, if less freshwater is flowing into
        an estuary, there may no longer be enough freshwater to supply the previous level
        of consumption.

              Another response is to shift to alternative supplies.      For example, if
        flows in the Mississippi River decline, or if wetland loss motivates policy
        makers to allow the river to change course, New Orleans would have to abandon the
        river as a supply of freshwater. Many argue that the river is polluted enough
        to view such a situation as a "blessing in disguise," and have suggested that the
        groundwater under Lake Ponchartraine would be a suitable source (Louisiana
        Wetland Protection Panel, 1987). Nevertheless, alternative supplies are finite

                                               447











              North America

              and may become increasingly scarce as the economy grows, especially in areas
              where the greenhouse effect fails to increase precipitatibn enough to offset the
              increased evaporation that warmer temperatures invariably imply.

                    Water conservation is likely to play an increasingly important role in
              efforts to adapt to reduced availability of freshwater.          Many jurisdictions
              already place restrictions on depletive uses, such as watering lawns and washing
              cars.   Officials in New Jersey are planning to ration*,'tho water that farmers
              withdraw from the Potomac - Raritan -Magothy Aquifer, which is recharged by the
              Delaware River. Nevertheless, regulations of water use are difficult to enforce
              and generally apply only to a limited number of visibl;e,activities.

                    In our view, the best long-term response would.be to treat water like any
              other scarce commodity: sell water at a market-clearing price, rather than at
              a price based on cost. There is an emerging trend in this direction among large
              water users in the western United States, but the ftinciple is likely to face
              severe cultural and institutional barriers. Firstl Americans generally believe
              that water should be as free as the air we breathe.! Second, public utilities
              generally are not allowed to make a profit.         'Nevertheless, with increasing
              government deficits and a gradual acceptance of the scarcity,'of water, the public
              would probably learn to accept water markets.

              The Need for Near-Term Action

                    As with dikes built to prevent inundation, there is'no need to build dams
              or canals to counteract future saltwater intrusion. . Nevertheless, setting aside
              sufficient land for future dam sites is similar to allowing wetlands to migrate
              landward: it will be less expensive to prevent peopl:6 from developing the land
              today than to buy people out later. Accordingly, to the extent that regions will
              rely on dams in the future, it would be best to identify those sites today and
              implement policies that will keep options open for future reservoir construction.

                    The matter of reserving land for dams or wetlands illustrates a principle
              that may apply to other commodities: even when a particular action will not be
              necessary for a few decades, it is best to establish the "rules of the game" in
              advance so that people can gradually take whatever measures are necessary based
              on how they perceive the probability and eventuality of the particular situation
              that is anticipated.      If we want to use water efficiently, its price will
              eventually have to rise. Political realities prevent a substantial rise today,
              but if the government put everyone on notice that it would-charge a fair-market
              price beginning in the year 2030, the public would probably accept such a policy.
              It is easier to agree on what is fair when no one is immediately threatened, and
              honorable people do not object to fulfilling the conditions of treaties,
              contracts, and other arrangements made by a previous generation.


              EVOLUTION OF THE U.S. RESPONSE: 1982-1989

                    For most practical purposes, the United States began to seriously examine
              potential responses to accelerated sea level rise in the summer of 1982. Two

                                                       448











                                                                                       Titus

         officials of the U.S. Environmental Protection Agency (EPA), John Hoffman and the
         head of his office,    Joseph Cannon, were troubled by an apparent failure in
         information transfer.    For several years, climatologists had      warned that a
         global warming due to,the greenhouse effect was likely (NAS, 1979, 1982). Yet
         federal, state, and local officials responsible for coastal decision making
         either were generally  unaware of this prospect or viewed it as mere speculation.

               No one had estimated the likely rise in sea level for specific years, and
         even if they had, the EPA officials were not sufficiently familiar with coastal
         activities to know whether consideration of a possible rise would warrant changes
         in current decision making. But Hoffman had    a hunch that sea level rise would
         justify changes in at least some decisions, and convinced Cannon to initiate a
         small program to begin the process by which   the United States prepared to live
         with a rising sea on a warmer planet.

               In retrospect, it may seem strange that EPA, a regulatory agency
         responsible for controlling pollution, first addressed the greenhouse effect
         issue by initiating a program to adapt to a global warming, rather than a program
         to reduce emissions of greenhouse gases into the atmosphere. Even then, a number
         of environmental groups were initially suspicious that the Agency was effectively
         "throwing in the towel."       But in the context of what could actually be
         accomplished at the time, the strategic decision Cannon made was perfectly
         rational. The nation had just elected a new president who had promised to relax
         environmental regulations; nonregulatory approaches to protecting the environment
         seemed to have more promise. The planned sea level rise project would encourage
         state and local officials to anticipate sea level rise,         with the hope of
         averting situations that would otherwise eventually necessitate regulations.
         Moreover, there was no public consensus to reduce global warming; a project aimed
         at increasing awareness would help create the political conditions necessary for
         policy makers to consider reducing emissions of CO, and other greenhouse gases.

               The first major activity of the Sea Level Rise Project was an
         interdisciplinary study in which Hoffman et al. (1983) estimated the range of
         future sea level rise; Leatherman (1984) and Kana et al. (1984) used those
         scenarios to estimate the physical effects on Galveston, Texas, and Charleston,
         South Carolina; Sorensen et al. (1984) provided rough cost estimates for
         engineering responses to sea level rise; and Gibbs (1984) and Titus (1984)
         performed economic analyses using the information provided by the other
         researchers. The results were presented at a conference in Washington in 1983
         and were published the following year (Barth and Titus 1984).

               The initial effort was only partly successful.       On the positive side,
         Hoffman's study estimating sea level rise prompted the National Academy of
         Sciences to prepare their own estimate (Revelle 1983), so that by the end of the
         first year, there were two available studies, both of which suggested that a
         substantial rise in the next century was likely.      We were also successful in
         making officials and coastal scientists aware of the  potential for a significant
         rise: (1) our reports were written for the layman -- no matter how technical the
         subject matter of a study, they always included an overview chapter that
         explained the contents; (2) we sent out form letters  to most of the people in the

                                                 449











               North America

               country working on coastal issues, telling them how to obtain our reports, and
               about one-third of them responded by requesting at least one document; and (3)
               we gave about 50 speeches and briefings every year on the subject to government
               offices and public meetings.

                     However, we failed to obtain our most important objectives. By 1984, we
               had identified only a handful of issues where we could make a case that sea level
               rise required changes in current practices.     Moreover, while we continued to
               study the issue, we were generally unable to convince federal and state agencies
               with a stake in sea level rise to undertake efforts themselves to address the
               issue. There were four notable exceptions: (1) the National Academy of Sciences
               formed panels to (a) estimate the future contributions of glaciers to sea level
               rise (Meier et al., 1985) and (b) assess the engineering implications of a
               possible rise (Dean et al., 1987); (2) Orrin Pilkey, the most prominent
               environmental activist on coastal matters, began to incorporate global warming
               into his many speeches to civic groups on the need for coastal development to
               be more sensitive to environmental processes; (3) the Army Corps of Engineers
               agreed to cofund with EPA a $25,000 study on the implications of sea level rise
               for coastal protection works (Kyper and Sorensen, 1985); and finally (4) the
               legislature of Terrebonne Parish, a local government in Louisiana, passed a
               resolution calling on Congress to improve estimates of future sea level rise and
               initiated a $100,000 study on response strategies for their community, which was
               already facing substantial erosion due to subsidence (see Edmonson, Volume 1).

                     It was clear that we were doing something wrong, so in mid-1984 we changed
               the focus of our studies. From then on, we decided to fund studies only after
               we had internally developed a specific hypothesis demonstrating that a
               consideration of sea level rise would alter decisions people make today. In the
               ensuing two years, we commenced studies to investigate the following hypotheses:
               (1) sea level rise would destroy a large fraction of our coastal wetlands unless
               planning solutions were soon implemented to require development to be abandoned
               to allowwetlands to migrate inland (Titus et al., 1984); (2) because groins help
               to control erosion due to alongshore transport but not the offshore erosion from
               sea level rise, a consideration of the issue would prompt the State of Maryland
               to drop its plans to build more groins at Ocean City, Maryland, and instead
               employ beach nourishment; (3) because it is much easier to put slightly larger
               pipes in a coastal drainage system during construction than subsequently to add
               new pipes, it would be rational to design new coastal drainage systems with an
               allowance for sea level rise; (4) sea level rise would accelerate the already
               alarming rate of land loss in Louisiana, and hence, imply that action is much
               more urgent than currently assumed; and (5) increased salinity in the Delaware
               Estuary might    eventually   necessitate   additional   reservoirs   to   protect
               Philadelphia's water supplies, and although they need not be built today, the
               risk of this eventually happening warrants land use planning to ensure that all
               the suitable sites are not developed.

                     Because we had conducted "back of the envelope" assessments that
               demonstrated the need to consider sea level rise before funding them, all of the
               studies turned out to demonstrate that even a 50-50 chance of accelerated sea
               level rise would warrant changes in current decision making. Although sea level

                                                      450











                                                                                         Titus

          rise was probably not the only reason, within a month of the Ocean City study's
          (Titus et al., 1985) release, the State of Maryland announced that it would shift
          its erosion-control strategy from groins to beach nourishment (Associated Press,
          1985). (The wetland study (Titus, 1988) was not released until much later, but
          even while it was still in draft, the State of Maine responded by issuing
          regulations requiring that structures be removed if necessary to enable wetlands
          and dune ecosystems to migrate landward.)

                Although the other studies (Titus et al.,          1987; Louisiana Wetland
          Protection Panel, 1987; Wilcoxen, 1986) did not precipitate specific actions,
          they provided additional examples to buttress our claim that people should begin
          preparing for sea level rise, even though it is uncertain. We continued to give
          about 30 speeches a year on the subject to various communities and professional
          organizations, trying where possible to talk to enough people beforehand to
          develop a hypothetical example relevant to their own activities where planning
          for sea level rise today would be warranted. The fact that we could cite studies
          demonstrating the rationality of planning today increased the credibility of our
          assertion that the particular audience should consider it as well; and the fact
          that Maryland and later Maine had made a decision based on sea level rise helped
          convince people that policy makers are capable of planning for the long-term
          future.

                Although many scientists, reporters, low-level officials, and members of
          the public continued to request our reports, in the beginning of 1986 we knew
          that we had failed to achieve our primary goal of motivating people to prepare
          for sea level rise.    We had the sense that we were fulfilling a need to have
          someone thinking and telling people about the long-term implications of current
          activities, but that for most people, our activities were little more than a
          curiosity; practical people could safely ignore the issue of sea level rise.

                But then the British Antarctic Survey discovered an emerging hole in the
          ozone over the South Pole.       This seemingly unrelated event attracted the
          attention of several U.S. Senators, who held hearings on the subject and decided
          to include the related issue of global warming.       Suddenly, widespread public
          attention was focused on the greenhouse effect and its impact on sea level. The
          unusually hot year of 1988 further increased public awareness. For the first
          five years of our project, we were able to motivate only a few agencies to
          undertake any substantive efforts; in the last two years, the momentum of the
          issue has motivated dozens of initiatives, as Klarin and Hershman (Volume 1)
          discusses.

                We would like to think that our initial efforts laid the groundwork for the
          emerging response to sea level rise, even though at the time our efforts seemed
          futile.   By this line of reasoning, our initial reports explaining the issue
          convinced low-level officials, low-level environmental spokesmen, and coastal
          scientists that sea level rise is important, but failed to convince high-level
          officials, heads of nongovernmental organizations, or prominent scientists that
          the time was ripe for addressing the issue. When the ozone hole and hot year of
          1988 convinced leaders that global warming is a serious issue, their lower-level
          counterparts were already informed and ready to recommend action.

                                                  451











              North America

                    We will never know whether our efforts made much of a difference in the
              final analysis. Nevertheless, on the assumption that they did, we briefly offer
              a few lessons that may be useful for nations beginning to prepare for future sea
              level rise. First, it is important to designate an individual to work full time
              on the issue. A key to the success of the EPA project is that Hoffman was able
              to find someone who was sufficiently interested in the issue to stay with it for
              the better part of a decade. It takes time to develop expertise
              when a new issue emerges: much of the relevant informatfon is unpublished, and
              disciplines ranging from law and economics to biology and engineering must be
              synthesized.

                    Second, because responding to sea level rise is likely to be decentralized,
              public information is sufficiently important to warrant 10-20 percent of the
              total budget and 25 percent of the project manager's time. Thousands of one-hour
              conversations with reporters and professionals working on related issues will be
              necessary, as well as many shorter conversations with curious citizens. Anyone
              who views their time as too valuable to completely satisfy all inquiries is
              doomed to failure.     College students and low-level assistants who have the
              initiative to question the project manager about the implications of future sea
              level rise often surface later as influential researchers or directors of
              organizations. Although the typical conversation on the subject may accomplish
              little, the totality of thousands of conversations over the course of several
              years produces a critical mass by which people begin to talk to each other about
              the issue and spend their own time investigating its implications.

                    If the need to satisfy all inquiries is recognized, the project manager
              will find that he or she can save time by preparing summary reports that explain
              the issue to someone with no background in the issue. Managers of government
              projects often commission numerous studies, and in their own minds, develop a
              broad vision of the issue.     But while they make the studies available, they
              rarely prepare reports summarizing their perspective. This is unfortunate both
              because preparing such reports disciplines one to examine the weaknesses in their
              opinions, and because their overviews of the issue would correspond more closely
              to what the public needs to know than would the reports prepared by specialists
              in particular disciplines.

                    Finally, studies should begin with a socially relevant hypothesis before
              being funded.    In our case, the hypothesis was that a particular change in
              current activities was warranted even if one allows for the possibility that sea
              level might not rise. In some cases, it is worth examining an issue just to make
              sure that no action is yet necessary. However, any project manager unable to
              present a cost-benefit argument in favor of action today in at least a few cases
              should be criticized for, at best, a lack of imagination and for, at worst,
              directing resources to the wrong issues and thereby forfeiting any savings that
              might be  realized from preparing for sea level rise in other ares.             Such
              criticism may not always be fair, but the fear of receiving it will be a powerful
              incentive to ensure that "no stones go unturned."




                                                      452











                                                                                             Titus

          CONCLUSION

                No one would accuse the United States of overreacting to the prospect of
          a rise in sea level, from the greenhouse effect; the process has been slow, but
          steady.    After seven years, we have reached the point where the relevant
          disciplines and the relevant government agencies are considering the issue and
          looking for opportunities to respond. Everyone realizes that it is difficult to
          convince politicians to make short-term sacrifices for the long-term good, but
          we have a public that is concerned about environmental quality in general and
          the greenhouse effect in particular.

                We understand that many of the assumptions American researchers take for
          granted would not apply in other nations.         Nevertheless, we believe that two
          recommendations are universally appropriate for any foreign colleague who decides
          to dedicate a number of years helping a nation prepare for rising seas. Focus
          your efforts on identifying actions that need to be taken today and make sure
          that no one ever considers you an expert on the issue. What you learn will be
          important only if its knowledge becomes commonplace.


          BIBLIOGRAPHY

          Armentano, T.V., R.A. Park, and C.L. Cloonan. 1988. Impacts on coastal wetlands
          throughout the United States.        In:   Greenhouse Effect, Sea Level Rise, and
          Coastal Wetlands.      Titus, J.G., ed.       Washington, DC:      U.S. Environmental
          Protection Agency.

          Associated Press. 1985. Doubled erosion       seen for Ocean City. Washington Post,
          November 14th. (Maryland Section).

          Barth, M.C., and J.G. Titus, eds. 1984.       Greenhouse effect and sea level rise:
          A challenge for this generation. New York: Van Nostrand Reinhold.

          Broadus, J.M., J.D. Milliman, S.F. Edwards, D.G. Aubrey, and F. Gable.             1986.
          Rising sea level and damming of rivers:             Possible effects in Egypt and
          Bangladesh. In: Effects of Changes in Stratospheric Ozone and Global Climate.
          Titus, J.G., ed.     Washington, DC:     U.S. Environmental Protection Agency and
          United Nations Environment Program.

          Dean, R.G., et al. 1987. Responding to changes in sea level. Washington, DC:
          National Academy Press.

          Everts, C.H.     1985.   Effect of sea level rise and net sand volume change on
          shoreline position at Ocean City, Maryland. In: Potential Impacts of Sea Level
          Rise on the Beach at Ocean City, Maryland. Washington, DC: U.S. Environmental
          Protection Agency.

          Gibbs, M. 1984. Economic analysis of sea level rise: Methods and results. In:
          Greenhouse effect and sea level rise: A challenge for this generation. Barth,
          M.C., and J.G. Titus, eds. New York: Van Nostrand Reinhold.

                                                    453









               North America

               Hoffman, J.S., D. Keyes, and J. G. Titus. 1983. Projecting future sea level
               rise. Washington, DC: Government Printing Office.

               Hul 1 , C. H. J. , and J. G. Ti tus, eds. 1986. Greenhouse effect, sea level rise, and
               salinity in the Delaware Estuary. Washington, DC: U.S. Environmental Protection
               Agency and Delaware River Basin Commission.

               Kana, T.W., J Michel, M.O. Hayes, and J.R. Jensen. 1984. The physical impact
               of sea level rise in the area of Charleston, South Carolina.            In:   Greenhouse
               effect and sea level rise: A challenge for this generation. Barth, M.C., and
               J.G. Titus, eds. New York: Van Nostrand Reinhold.

               Kana, T.W. , et al. 1986. Potential impacts of sea level rise on wetlands around
               Charleston, South Carolina.       Washington, DC:      U.S. Environmental Protection
               Agency.

               Kana, T.W., W.C. Eiser, B.J. Baca, and M.L. Williams           1988.   New Jersey case
               study. In: Greenhouse Effect, Sea Level Rise, and Coastal Wetlands. Titus,
               J.G., ed. Washington, DC: U.S. Environmental Protection Agency.

               Kyper, T., and R. Sorensen. 1985. Potential impacts of selected sea level rise
               scenarios on the beach and coastal works at Sea Bright, New Jersey. In: Coastal
               Zone '85.    Magoon, O.T., et al., eds.       New York:    American Society of Civil
               Engineers.

               Leatherman, S. P.     1984.    Coastal geomorphic responses to sea level rise:
               Galveston Bay, Texas. In:      Greenhouse effect and sea level rise: A challenge
               for this generation. Barth, M.C., and J.G. Titus, eds. New York: Van Nostrand
               Reinhold.

               Louisiana Wetland Protection Panel.       1987.   Saving Louisiana's wetlands:        The
               need for   a long-term plan of action.         Washington, DC:     U.S. Environmental
               Protection Agency.

               Meier, M.F., et al. 1985. Glaciers, Ice Sheets, and Sea Level. Washington, DC:
               National Academy Press.

               National Academy   of Sciences. 1979. CO, and Climate: A Scientific Assessment.
               Washington, DC:    National Academy Press.

               National Academy of Sciences.       1982.   CO, and Climate:     A Second Assessment.
               Washington, DC:    National Academy Press.

               Park, R.A., M.S.  Treehan, P.W. Mausel, and R.C. Howe. 1989. The effects of sea
               level rise on U.S. coastal wetlands.         In:    The Potential Effects of Global
               Climate Change on the United States.       Volume B: Sea Level Rise. Smith, J. and
               D. Tirpak, eds. Washington, DC: U.S.-Environmental Protection Agency.

               Revelle, R. 1983. Probable future changes in sea level resulting from increased
               atmospheric carbon dioxide. In: Changing Climate. Washington, DC: National
               Academy Press.


                                                         454












                                                                                              Titus

           Sorensen, R.M., R.N. Weisman, and G.P. Lennon.           1984.   Control of erosion,
           inundation, and salinity intrusion. In: Greenhouse effect and sea level rise:
           A challenge for this generation. Barth, M.C., and J.G. Titus, eds. New York:
           Van Nostrand Reinhold.

           Titus, J.G.     1984.   Planning for sea level rise before and after a coastal
           disaster.     In:  Greenhouse effect and sea level rise:        A challenge for this
           generation. Barth, M.C., and J.G. Titus, eds. New York: Van Nostrand Reinhold.

           Titus, J.G, S.P. leatherman, C. Everts, 0. Kriebel, and R.G. Dean.                 1985.
           Potential impacts of sea level rise on the          beach at Ocean City, Maryland.
           Washington, DC: U.S. Environmental Protection Agency.

           Titus, J.G.      1986.    Greenhouse effect, sea     level rise, 7@nd coastal zone
           managment.   Coastal Management 14:3.

           Titus, J.G., ed. 1988. Greenhouse effect, sea level rise, and coastal wetlands.
           Washington,  DC: U.S. Environmental Protection Agency.

           Titus, J.G. 1989. Greenhouse effect, sea level rise, and wetland policy: will
           Americans have to abandon an area the size of Massachusetts?             Submitted to
           Environmental Management (draft).

           Titus, J.G.     1990.   Greenhouse effect, sea level rise, and barrier islands.
           Coastal Management 18:1.

           Titus, J.G., T. Henderson, and J.M. Teal.        1984.   Sea level rise and wetlands
           loss in the United States. National Wetlands Newsletter 6:4.

           Titus, J.G., C.Y. Kuo, M.J. Gibbs, T.B. LaRoche, M.K. Webb, and J.0. Waddell.
           1987. Greenhouse effect, sea level rise, and coastal drainage systems. Journal
           of Water Resources Planning and Management 113:2.

           Titus, J.G., R.A. Park, S. Leatherman, R. Weggel, M.S. Greene, M. Treehan, S.
           Brown, and C. Gaunt. 1989. Greenhouse effect and sea level rise: Loss of land
           and the cost of holding back the sea. Submitted to Natural Resources Journal
           (draft).

           Wilcoxen, P.J.      1986.  Coastal erosion and sea level rise:       Implications for
           Ocean Beach and San Francisco's Westside Transport Project.              Coastal Zone
           Management Journal 14:3.

           Will iams, P.    1989.    The impacts of climate change on the salinity of San
           Francisco Bay. In: The Potential Effects of Global Climate Change on the United
           States.    Volume A: Water Resources. Smith, J. and D. Tirpak, eds. Washington,
           DC: U.S. Environmental Protection Agency.





                                                     455












             SEA LEVEL RISE: CANADIAN CONCERNS AND STRATEGIES


                                              K. B. YUEN
                                        Assistant Director
                            Oceanography and Contaminants Branch
                         Physical and Chemical Sciences Directorate
                              Department of Fisheries and Oceans
                                          200 Kent Street
                               Ottawa, Ontario, Canada, KlA OE6




          INTRODUCTION: THE CANADIAN CONTEXT

               Canada is a coastal nation bordering on three oceans and possessing over
          244,000 kilometers of coastline -- the longest of any nation in the world. A.
          number of major cities and highways border on the ocean. There are also hundreds
          of fishing villages, over one thousand small-craft harbors, and numerous fishing
          plants. Many native communities are also located close to the shore, near the
          marine natural resources upon which they traditionally depend for food. Various
          industries, such as pulp and paper mills, coastal shipping, container ports, and
          oil refineries, are also located at the shore for obvious marine transportation
          advantages.

               A rise in mean sea level is expected to have major impacts upon Canada's
          coastal resources and infrastructure. Fortunately for Canada, a large proportion
          of the coastline rises fairly steeply out of the sea, in the form of rocky shores
          and fjords, and is thus not at risk of flooding and erosion. Much of Canada is
          also remote. As a consequence of Canada's particular geography and relatively
          low population densities, the potential impacts in Canada of rising sea level,
          while expected to be of substantial significance and requiring specific policies
          and strategies for adaptation, are not expected to be catastrophic or even
          severe.   This is very much in contrast to countries that possess much more
          exposed coastal lowlands or that simply do not have the physical space to
          consider alternatives for human resettlement, even if they wanted to do so.

               In much of Canada, coastal impacts arising from higher ocean temperatures,
          changes to river runoff, and related changes to the oceanography, circulation
          patterns, ice cover, and hydrological cycle may be more important than those
          resulting from sea level rise.      For example, Pacific cod are already at the
          southern limit of their distribution and may move north if water temperatures
          increase substantially. Canadians are generally more concerned with noncoastal
          impacts, such as potential shifts in agricultural and forestry patterns,

                                                  457











              North America

              hydroelectric power generation and lower water levels in the Great Lakes. (These
              impacts are addressed by the "RUMS" subgroup of IPLC work group 3.)

                   In Canada, the assessment of sea level rise and the development of adaptive
              options is still in its infancy.   In the context of climate change, four recent
              studies have been carried out: three relate to the impacts of sea level arise
              on specific coastal cities (Charlottetown, Prince Edward Island; St. John, New
              Brunswick; and Vancouver, British Columbia), and the fourth provides an overview
              of impacts in Atlantic Canada. Generally, these studies have been based on the
              hypothetical scenario of a one-meter rise, which is then superimposed upon the
              20- and 100-year flood levels. This information is then superimposed on maps
              of coastal resources to estimate the resources at risk. The Vancouver study also
              looked at scenarios of 2- and 3-meter rises in sea level (Figure 1).     It can be
              concluded from these studies that the economic impacts of sea level rise can be
              estimated reasonably well . However, the ability to predict the impacts on natural
              ecosystems generally, and on marine ecosystems in particular, has not yet
              advanced very far, which reflects the complexities of those systems and the level
              of scientific ignorance.


              POTENTIAL IMPACTS AND POSSIBLE ADAPTIVE OPTIONS

                   To review some of the specific impacts that might occur in Canada and some
              of the potential adaptive options, it is useful to adopt a general hypothesis
              of a one-meter rise in sea level (as opposed to looking at a 5-meter rise) over
              the next 50 years. Based on present trends and predictions, a change of this
              magnitude is a useful starting point for examining the need for coastal zone
              management decisions over the next 10-25 years.

                   We caution that Canadian studies have not yet considered the vertical
              movement of the Earth's crust.      Data for the east coast show considerable
              spatial variability.    For example, in the Gaspe Peninsula, land is rising as
              much as 40 centimeters per century; while in southern Newfoundland (400
              kilometers to the east), land is subsiding about 50 centimeters per century; and
              at the northern tip of    Newfoundland (a further 400 kilometers north), it is
              rising at 100 centimeters per century (Figure 2).      Thus a rise in global sea
              level would not necessarily imply a relative rise in sea level at all locations;
              it might simply decrease the current rate at which sea level is falling. Similar
              spatial variability has been observed on the west coast, where both tectonic
              processes and glacio-isostatic rebound contribute to sea level change.          The
              removal of groundwater and the extraction of offshore and nearshore hydrocarbon
              resources may also cause subsidence and compaction. The key points are that all
              of the contributing processes have to be integrated to arrive at the overall net
              change of mean sea level, and that these changes will vary from place to place.

                   Following are some of the key impacts expected in Canada and the adaptive
              options to deal with them.




                                                     458








                                                                                                                               Yuen



                                                      ..... . ....
                                                                                                                 silt &
                                                                                                  LAND            clayon
                                                                                                               swamp
                                                                                                                 & bog
                                                      VANCOUVER                                                    salt
                                                                                                                 marshrm
                                                                                                  SEA            silt &
                                                      4#1              0                 5                        clayF--]
                                   0
                                                                                                                 sandE3
                                                                              (km)
                                                                                                                 dyke
                                          Is
                                      lovis
                                             %q
                                      Ir
                                      7                  Sea
                                                    1    @4

                                    'STURGEON
                                         BANK
                                o.o      TIDAL
                                                                           bog
                                         FLAT
                                                                            L.Uiu                             4P

                                                                                    island


                                    Ic
                                     (b
                             j
                                                                                                              bog


                                 To*




                                                                           Nz,

                                                                                   ilt
                                                                                                                     13
                                                                                                      @.7
                                               Oki
                                            00    ON

                                                                                         ilk

                                               ioi   oit
                                                                      Sri
                                                                                                              ean    rl
                                                     10                                                          water



                                                                                                     .4k
                                                                                        Point
                                                                                          Roberts
                                                                                         Peninsula
                              STRAIT
                               OF
                           GEORGIA


               Figure 1. Geologic map of the low-lying Fraser River Delta region of heavily
               populated Greater Vancouver, B.C. Map shows the location of dykes to prevent
               flooding of deltaic islands.                    Broken line marks seaward limit of the delta
               foreshore. Arrows indicate direction of present advance or retreat of the delta
               front, solid bars denote no change (R.E. Thomson, personal communication).

                                                                        459











             North America


                                           HALIFAX TIDE GAUGE
                          1.3-




                          1.2-
                       rr
                       LLJ
                       I---
                       LU



                          1.0 r
                              1900        1920        1940        1960       1980

                                                     YEAR

             Figure 2.   Sea level at Halifax, Nova Scotia is already rising at the rate of
             0.3 meters per century.    This is thought to be post-glacial adjustment, the
             greenhouse effect could greatly accelerate the trend.


             Coastal Infrastructure

                  With a rise in sea level, coastal infrastructure related to human settlement
             and industrial development on all coasts will be subjected to some level of
             increased flooding. In some cases, this risk will be new; in others, existing
             flood risks will     be exacerbated by increased water levels.             Coastal
             infrastructure so affected may be grouped into three general categories, namely:

                  ï¿½   existing permanent structurgs that would suffer loss or damage solely
                      attributable to a rise in sea level.       Replacement or preventive
                      strategies,   including   resettlement,   would   require    major    new
                      expenditures.   However, depending on the magnitude of the potential
                      loss or damage, investment in adaptive options may be unavoidable. The
                      loss of valuable waterfront land would also fall into this category, but
                      it might be offset by reclamation/landfill projects.

                  ï¿½   existing nonpermanent structures with finite life expectancies, which
                      would normally need to be replaced within the next 50-75 years anyway.
                      With careful planning, the incremental cost of taking sea level rise
                      into account when structures are replaced may be negligible in these
                      cases.

                  ï¿½   new or planned infrastructures. The opportunity exists now to design
                      such structures to avoid or minimize the impact of sea level rise, also
                      at minimal cost.

                  In  short, advance planning taking sea level rise into account before
             construction is the most intelligent and cost-effective approach to the
                                            440e@




                                                    460











                                                                                           Yuen

           development of new coastal infrastructure. Based on the studies to date, the
           cost of replacing or modifying coastal infrastructures in Canada in response to
           sea level rise could be in the range of U.S. $3-4 billion or more.         A large
           fraction of this cost could be avoided by incorporating sea level rise into
           routine maintenance and reconstruction costs.

           Homes, Buildings, and Roads

                In most coastal cities, a number of waterfront properties and structures
           will be subject to flooding from a one-meter rise in sea level. Higher levels
           will increase the risks posed by surface waves, tides, ice jams, storm surges,
           river runoff, and sea ice. Accurate risk assessment will require detailed data
           compilation and flood zone mapping at the local level.

                The mitigative options range from permanent floodproofing of individual
           structures frequently subjected to flooding to temporary protective measures
           for areas subject to infrequent flooding.     Where there are extensive lowlands
           and the value of the affected infrastructure justifies it, a system of protective
           dikes may be created. In the residential area of Richmond, British Columbia,
           south of Vancouver, which constitutes high-price real estate located on a delta,
           a diking system already exists. However, it would need to be topped off to allow
           for higher sea levels, storm surges, and waves. Further new diking would be
           needed if flooding threatens other farmlands within the river valley. In the case
           of much less valuable property, such as the Village of Tuktoyaktuk (comprising
           Inuit homes, oil company exploration shorebases, and an airport) located on the
           shores of the Beaufort Sea and Arctic Ocean, it may be more cost-effective to
           actually move the location of the town, or at least the flood-prone sections,
           to higher ground. Fortunately for Canada, few situations will actually require
           large-scale human resettlement.

                Finally, new development on the waterfronts of Canada's major cities (for
           residential, commercial, industrial, transportation, and recreational purposes)
           continues to draw considerable business investment, simply because the waterfront
           is one of the most desirable places to be.   Property zoning, construction codes
           and standards, and coastal zone planning processes need to take into account
           the explicit possibilities of sea level rise.

           Municipal Sewers and Water Supplies

                A rise in sea level will affect the operation of sewer outfalls.             In
           addition, there will be flooding of existing storm and sanitary sewers located
           near the water, which will result in either corrosion of the sewer pipes or a
           backing up of the sewer systems resulting from inhibited outflows from the higher
           sea levels at the outfall to the sea. Such flooding will in turn cause property
           damage and create a health risk, including possible contamination of the drinking
           water system.    In light of the overriding public health considerations, a
           modification of the affected sewage and water supply systems is inevitable.       In
           many communities, new sewers and sewage treatment systems are being planned at
           a cost of billions of dollars. To protect those investments, it is essential
           to design now for higher sea levels in the future.

                                                  461











             North America

             Ports, Small-Craft Harbors, Breakwaters, and Fish Processing Plants

                  By their very nature, such facilities need to be located near the water's
             edge. In Atlantic Canada alone, there are over 1,000 small-craft harbors, over
             100 federal government wharves, 13 ferry terminals, 21 marine service centers,
             and over 500 fish-processing plants.

                  The routine maintenance and replacement of wharves probably could be planned
             to take into account higher sea level.      Wharves will definitely need to be
             raised. Old Federal wharves, for example, are only 1 meter above normal high
             tides, but newer wharves are meters higher. Fish plants would ha   ,ve to be'moved
             further inland or somehow modified to keep the work areas dry. For small-craft
             harbors, a rising sea would (at least slightly) reduce maintenance dredging
             requirements.

                  On the other hand, changes in currents, circulation, wave and ice patterns,
             river deposition, and the resulting changes in shoreline erosion patterns could
             more than offset such savings. Site-specific assessments and engineering studies
             would be needed. Not only might breakwaters have to be raised to afford better
             storm protection from higher seas, but their location and configuration might

             need to be changed to adapt to new wave refraction patterns and changes in the
             way rivers deposit sediment.

             Roads, Bridges and Causeways

                  Canada has an extensive network of roads, small bridges, and causeways
             throughout its coastal region. Many of these structures would be vulnerable to
             a one-meter sea level rise.    The corrective measures would include relocating
             or raising roads, reinforcing and raising causeways, and raising bridges -- all
             at a cost significantly greater than normal maintenance costs. Some major new
             causeways are at the planning stage -- e.g, the causeway to Prince Edward Island
             -- but proper planning can allow for higher sea level and changing ice regimes.

             Erosion

                  Coastal erosion is a problem in many parts of Canada, especially on the
             east coast (Figure 3). In some cases, shores are retreating as much as 5 meters
             each year. Sea level rise is generally expected to aggravate the problem.
             However, the actual response of vulnerable shorelines will also depend on changes
             to wind and wave patterns, currents, the geology and geomorphology, the ice
             regime, local land subsidence, and sediment supply limitations. Our ability to
             predict the timing and magnitude of changes to erosion patterns will require
             further research on a site-specific basis.         Realistically, however, the
             implementation of shoreline protection measures will only be economically
             feasible for those areas where the val tue of the shoreline investment is
             sufficiently high, such as residential and recreational developments, harbors,
             power plants, and other infrastructure.



                                                    462














                                                                       IN
                                                                                         Yuen




















          Figure 3.   Accelerated erosion  can be expected   in places where an  increase in
          mean sea level would allow wave-induced erosion to attack vulnerable cliffs
          instead of dissipating on the beach, as in this area at the head of the Bay of
          Fundy.


          Tidal Power

               One of the more interesting coastal development concepts in Canada is that
          of tidal power in the Bay of Fundy, where the tidal range is as much as 10-12
          meters in some locations. From numerical models, it has been calculated that
          an increase of 1 meter in sea level at the ocean entrance (Georges Bank) would
          increase the tidal range at the head of the bay by about 1.7% -- that is, by 20
          centimeters. Therefore, the height of the tidal power barrage would need to be
          raised by about 1.2 meters.      Fortunately, the increase in tidal range also
          results in greater power output, so that if development proceeds, the increased
          cost of engineering and construction will be roughly balanced by the increased
          revenues from power generation.

          Estuaries

               The question of impacts in our estuaries has not generally been resolved
          and requires further research and site-specific studies. In general, one would
          expect a rise in sea level to extend partway upstream, which would raise water
          levels and salinities. However, water levels will also be directly controlled
          by the extent of river outflows and ice cover. Outflows will vary from one part
          of the country to another and require accurate predictions of temperature and
          precipitation.

                In the St. Lawrence River, a related concern is the expected lowering of
          water levels in the Lower Great Lakes by 30-80 centimeters, which would decrease
          the outflow of the St. Lawrence River by 20%. This, in turn, would not likely

                                                  463











               North America

               decrease water levels in the river.       The net result of these complexities,
               including crustal movements, is considerable uncertainty in the expected rise
               or fall of sea level in our estuaries, and it is too soon to design adaptive
               strategies. Much more basic and site-specific hydraulic research needs to be
               conducted before we even know what conditions we need to adapt to. (Note: The
               drop in lake levels is independent of sea level rise, and is generally, expected
               to result from increased.evaporation at higher temperatures).

               Agricultural Lowlands

                   A small percentage of Canada's agricultural production takes place near
               the ocean shoreline, primarily inthe Fraser River delta and in low-lying lands
               on the east coast. Many of these areas are already diked, and they also have
               "aboiteaux," which are essentially tidal gates that allow water to drain from
               these lands during low tide. The solution to combat sea level rise will be to
               gradually increase the height and extent of these structures.        Moreover, new
               dikes and weirs may need to be built along the shores of the Fraser and St.
               Lawrence Rivers as rises in sea level extend farther upstream.

               Marshes, Wetlands, and Wildlife Habitat

                   The key areas that may be affected are easy to identify and are located
               mainly in the major estuaries and deltas (the Fraser, St. Lawrence, MacKenzie
               Rivers) and low-lying lands along the southern shores of Hudson Bay and on the
               east coast. However, the impacts are not so easy to predict.

                   No doubt, a sea level rise will inundate parts of these habitats.             But
               where topographic gradients permit, and if sea level changes slowly enough, these
               productive systems will hopefully reestablish themselves farther up the
               shoreline, and various biological species and their food supplies will recolonize
               or adapt to their new surroundings. It is also possible that such habitat may
               not be reestablished.   For large remote areas, such as Hudson Bay, it is very
               likely that no adaptive options are practical, except to allow nature to run
               its course. For less remote areas, critical habitat might be replaced by manmade
               development of new habitat at nearby locations, but at considerable effort and
               cost.

                   For some fish and. other species of economic importance, new habitat is
               already being created as part of a Fish Habitat Management Policy, which strives
               to achieve no net loss of natural habitat. On the west coast of Canada,
               significant amounts of new habitat for salmon have been created by planting eel
               grass in several major salmon estuaries. Further habitat development is a
               practical means of mitigating losses of salmon and trout habitat from sea level
               rise in estuaries and rivers.

                   Econom 'ic approaches also exist to replace lost production of certain
               economically valuable fish species that spawn or grow in estuaries and the
               nearshore.   Salmon are being produced on a large scale through artificial
               enhancement, in which eggs from wild fish are recovered during the spawning
               season and grown in temperature -control led hatcheries to an appropriate size

                                                       464











                                                                                              Yuen

           before being released to the sea.      This approach does not resolve the habitat
           problem per se, but it does contribute to sustainable development and economics.

                 Another solution to the economic problem is commercial aquaculture. In
           Canada, a considerable aquaculture industry has developed over the past decade,
           mainly for salmon, oysters, and mussels. The industry's value has grown from
           $13 million in 1982 to $100 million in 1988, mainly on the Pacific coast, and
           further major expansion, especially to the east coast, is projected. Clearly,
           there is an economic opportunity here that can also assist in mitigating the
           effects of rising sea level.

                 Finally, it must be noted that the key climate issue facing fisheries in
           Canada is not sea level rise, but the changes in water temperatures, circulation
           patterns, wind-induced upwelling, and other factors that will          determine the
           future distribution, recruitment, and production of fish. This              has major
           implications for national and international resource management strategies and
           agreements, fishing industrial strategies, and regional            economics.      (See
           Everett, Volume 1, for additional discussion of response strategies to protect
           fisheries).


           FUTURE ACTION

                 From a coastal zone management point of view, a considerable degree of
           skepticism exists in Canada regarding the risk of sea level rise over the next
           few decades and beyond.         It must be recognized that while research and
           understanding of climate change takes place at national and international levels,
           a large part of the decision making to mitigate local and regional effects takes
           place at the local or regional level of government. At what stage of research
           and assessment will there be sufficient knowledge and understanding to encourage
           or persuade natural resource managers and local officials to actually allow for
           higher sea levels in planning for habitat management and protection; for the
           owners of real estate and infrastructure in the coastal zone to actually spend
           money to floodproof     existing buildings or to invest in diking and other
           protective measures,    or to make the increased investment in planned coastal
           works needed to avoid    future flooding, or even to ensure that rising sea level
           is taken into account in existing coastal planning and decision making processes?
           Whatever that point of credibility may be, it is clear that we are still far from
           reaching that point.

                 Where, then, do we go from here? I believe that the following actions are
           needed:

                 ï¿½   Continue   research on global       climate change to      reduce current
                     uncertainties in the prediction of sea level rise resulting from global
                     warming.

                 ï¿½   Encourage further research and monitoring related to sea level change,
                     which must include the contribution of vertical movements of the Earth's


                                                     465










             North America

                      crust and groundwater depletion to relative sea level change as well as
                      global warming effects.

                   ï¿½  Develop   regional  models   for  climate   change,   and  carry   out
                      multidisciplinary site-specific studies that integrate all the factors
                      that influence net changes to water levels in estuarine and coastal
                      areas, including interactions among precipitation and runoff, tides, ice
                      cover, crustal movements, erosion, sedimentation, storm surges, and
                      waves.

                   ï¿½  Improve the scientific understanding of marine coastal ecosystems in
                      order to conduct ecological impact assessments related to rising sea
                      level.

                   ï¿½  Develop detailed inventories and mapping of coastal infrastructure and
                      natural resources in areas potentially affected by changes in sea level,
                      in order to facilitate improved impact assessments.

                   ï¿½  Continue research into coastal geomorphology and sedimentology in order
                      to understand coastal erosion processes, to predict the impacts of
                      higher sea levels, and to develop adaptive strategies.

                   ï¿½  Encourage multidisciplinary impacts research related to sea level.

                   ï¿½  Encourage the innovation and development of adaptive options.

                   ï¿½  Facilitate the public dissemination of information and research results
                      relating to sea level rise.

                   ï¿½  Encourage those involved with coastal zone management, building
                      standards/codes, property zoning, and sustainable development planning
                      to take into account the future possibilities for rising sea levels.
                      Development of flood-prone lands must be discouraged, by legal
                      prohibition if necessary.


             BIBLIOGRAPHY

             Anon. 1989. The full ra nge of responses to anticipated climatic change. United
             Nations Environment Program and Beijer Institute, April.

             Forbes, L.B., R.B. Taylor, and J. Shaw. 1989. Shorelines and rising sea levels
             in eastern Canada," EPISODES, Vol. 12, No. 1, p. 23-28.

             Lane, P. et al. 1988. Preliminary study of the possible impacts of a one-meter
             rise in sea level at Charlottetown, Prince Edward Island. Climate Change Digest,
             Report No. CCD 88-02, Environment Canada, Ottawa, Canada.

             Martec Limited. 1987. Effects of a one-meter rise iii mean sea level at Saint
             John, New Brunswick and the lower reaches of the Saint John River.         Climate

                                                    466











                                                                                                Yuen

            Change Digest, Report No. CCD 87-04, Environment Canada, Ottawa, Canada.

            Sanderson, M. 1987. Implications of climatic change for navigation and power
            generation in the Great Lakes.       Climate Change Digest, Report No. CCD 87-03,
            Environment Canada, Ottawa, Canada.

            Scott, D.B., and D.A. Greenberg.        1983.    Relative sea level rise and tidal
            development in the Fundy Tidal System.         Canadian Journal of Earth Sciences,
            20(10):1554-1564.

            Smith, J.V.   1989. Possible impacts of mean sea level rise scenarios on downtown
            Vancouver. Unpublished manuscript prepared for Atmospheric Environment Service,
            University  of Waterloo, Ontario, Canada.

            Stokoe, P.     1988.   Socioeconomic assessment of the physical and ecological
            impacts of  climate change on the marine environment of the Atlantic region of
            Canada - Phase 1.     Climate Change Digest, Report No. CCD 88-07, Environment
            Canada, Ottawa, Canada.
































                                                      467











                    THE LOWLANDS OF THE MEXICAN GULF COAST



                                  MARIO ARTURO ORTIZ PEREZ
                                        CARMEN VALVERDE
                                    Instituto de Geografia
                         Universidad Nacional Autonoma de Mexico
                                     Mexico City, Mexico

                                       NORBERT P. PSUTY
                       Center for Coastal & Environmental Studies
                      Rutgers - The State University of New Jersey
                                  New Brunswick, New Jersey

                                         LUIS M. MITRE
                                    Instituto de Geologia
                         Universidad Nacional Autonoma de Mexico
                                     Mexico City, Mexico






         ABSTRACT

              Mexico's Gulf of Mexico coast is largely lowland subject to a large range
         of marine influences. Of six large lowland areas that are subject to relative
         widespread flooding, four are within deltaic systems.

              The coastal zone has been undergoing considerable change as a result of port
         development related to the extraction of oil and to the concentration of oil
         refineries and petrochemical plants.     This area has also undergone a great
         expansion of commercial agriculture, cattle ranching, and high-cost tourist
         development.

              There are, at present, many conflicts between the development interests and
         the local economies based on the coastal resources.            The intensity of
         exploitation is currently causing serious deterioration of the environment, which
         is produced by a combination of the cultural processes superimposed on the
         natural changes. The losses of marshlands, mangroves, and other aspects of the
         coastal aquatic system are problems that need to be addressed. Although attempts
         have been made to control some of the changes by constructing coastal protection
         devices, these "solutions" have been neither well-planned nor successful. An
         awareness of the dynamics of the coastal system and the changes driven by a
         rising sea level must be introduced into the decisionmaking process.

                                                469










               North America

               INTRODUCTION

                    Approximately two million Mexicans live within five meters above sea level.
               Although a one-meter rise would inundate only a fraction of the nation's coastal
               zone, it would threaten some of the most valuable land, including tourist
               resorts, port facilities, and the wetlands that support an important fishing
               industry.

                    The intent of this paper is to summarize the present state of knowledge
               concerning   the   physiographic   information,   the wetland     areas,   and   the
               socioeconomic aspects of the Mexican Gulf Coast and to identify some of the
               impacts to the system as a result of a future sea level rise.


               IMPACTS OF SEA LEVEL RISE

               Physical Effects

                    Sea level rise particularly threatens the barrier islands along the Gulf of
               Mexico; as sea level rises, they will gradually narrow and some will shift
               inland. The islands in front of the southern portion of the Laguna Madre will
               certainly shift landward, and additional inlets are likely to form, further
               segmenting these islands.     On the other hand, the barrier in front of the
               Tamiahua Lagoon will narrow at first, although it will eventually break up as
               well.

                    The high, dune-lined barrier islands near Veracruz, Alvarado, and
               Coatzacoalcos have sufficient size and mass to resist erosion, at least in the
               early years.   There will be some loss of sediment and there will be a slight
               shift of the beach into the dune zone, but the effects will be limited. Along
               the Tabasco -Campeche barrier system, the effects will vary:   In western Tabasco,
               the barriers in front of most of the smaller lagoons will be   removed by overwash
               and breaching, creating a very indented shoreline.        The  area from Tupilco,
               Tabasco, to Champoton, Campeche, is very low but very wide.    Along this segment,
               the coast will erode at a very rapid rate as sea level reaches to higher levels
               and removes sediment from the low-lying beach ridges. The oil port of Dos Bocas
               will be increasingly exposed to storm effects and breaching of the jetties and
               shore protection structures.

                    The very narrow barrier along the Yucatan Peninsula will diminish greatly
               in size and probably break up. The salt-evaporation ponds at Progresso will be
               threatened as they are initially overtopped by inundation with higher sea level
               and then erosion as they become exposed to wave attack. The barrier island at
               Cancun will become every narrower and more liable to storm damage as sea level
               rises, thus threatening all existing and future infrastructure.

                    Mexico's wetlands would also be vulnerable to a rise in sea level,
               especially given the impacts of economic development. Their inundation would
               normally be balanced by an upward growth as organic and inorganic matter
               accumulates to a new level.     The problem of sea level rise is compounded in

                                                      470










                                                                              Ortiz, et al.

          Mexico because nearly all of the major rivers leading to the vast wetland areas
          are dammed and the sediment supply has been attenuated for decades. The product
          of the sea level rise and a decreasing sediment supply will lead to a loss of
          wetland area and a loss of primary productivity of the wetlands, the estuaries,
          and the adjacent nearshore areas. This could lead to serious deterioration of
          the local fisheries industries, independent of problems of pollution and
          overfishing.

               The wetlands of Laguna Madre and the Tamiahua Lagoon have already shown the
          effects of a limited sediment supply. Their bordering wetlands are very narrow.
          The Alvarado Lagoon and the Papaloapan lowlands will show a cons i derabl e'change
          both as a result of the higher water level and the severe loss of sediment supply
          coming into the estuary.

               The Grijalva lowlands will be the most seriously affected because it is the
          largest wetland area in Mexico and because of local subsidence and sediment
          starvation associated with the Malpaso Dam. Wetlands are already migrating onto
          the slightly higher coastal beach ridges and sand dune topography, while the
          bodies of open water are increasing and the shoreline is migration inland. The
          new population centers there and the petroleum industry will be affected as the
          water table rises and it becomes more difficult to drain the surface water off
          the land and lead the sewage away.

          Socioeconomic Implications

               Port activity could be affected by the sea level rise, especially in areas
          where the infrastructure is essentially at beach level, such as at Campeche,
          Ciudad del Carmen, Frontera, Dos Bocas, and parts of Coatzacoalcos and Veracruz.
          In Carmen, Frontera, and Dos Bocas, there is no higher ground to accommodate a
          landward retreat. The landscape is only a few meters above sea level and any
          increase will expose these sites to greater storm damage.

               Much of the lowland is used for some type of economic activity.           Oil
          exploration is certainly a common use throughout much of the coastal plain, and
          it is especially prevalent in the Tabasco lowlands. In addition, cattle pasture,
          coconut plantations, cacao, maize, sugarcane, lumbering, and fishing are
          important economic pursuits.   With the exception of fishing, all of the other
          economic activities will be adversely affected by a higher sea level because of
          the changing salinities and water table. Whereas the entire area will not be
          affected uniformly, the net effect will be a loss of surface area where each of
          these economic activities can be practiced. The petroleum industry will be able
          to conduct its exploration phase despite sea level rise. However, some of the
          stationary infrastructure may be negatively affected as shoreline erosion or
          higher water levels begin to encroach upon these structures.

          Responses

               One can reasonably expect that revenue-producing activities such as tourist
          beaches, ports, and petroleum activities will be protected with traditional
          coastal engineering measures. The casualties in this process will almost

                                                 471










              North America

              certainly be the environment and people pursuing traditional activities who lack
              the necessary resources to hold back the sea.

                   The coastal environment in Mexico is currently being exploited in manners
              likely to have an adverse impact in the long run. If we are unable to adequately
              address current environmental problems, how can we prepare for consequences of
              a rise in sea level that is still decades away?

                   Nevertheless, Mexico does have institutions that are capable of planning for
              the future, provided that the actions do not substantially undermine economic
              growth. In this regard, it seems wise to direct future coastal development to
              areas that are at least three meters above sea I evel ; not only would th is prevent
              future environmental impacts, but it would leave these areas less vulnerable to
              flooding even in the short term.      Similarly, along the ocean coasts, tourist
              facilities should be set back from the shore; this would make them less
              vulnerable to hurricanes and would enable the beach to survive       accelerated sea
              level rise.

                   But perhaps the most important first step in planning for sea level rise
              would be increased awareness on the part of the public in general and
              governmental officials in particular. Information transfer is a slow process.
              This is an area where researchers and universities can play an important role,
              rather than being outside observers and critics of governmental processes. The
              scientists and economists in Mexico need to begin discussing the implications
              of global climate change, so that we can better inform the policy makers of
              possible responses.

                   We note in particular that the Sea Grant College programs of California and
              Texas are interested in collaboration with Mexican scientists. We strongly urge
              these organizations to collaborate with the relevant Mexican Universities on the
              issue of sea level rise, with the goal of a bilateral conference on sea level
              rise similar to the Miami conference but focused on the common coastal problems
              facing states on either side of the U.S./Mexican border.


              THE COASTAL ENVIRONMENT OF MEXICO

              Coastal Geomorphology

                   The Mexican coast on the Gulf of Mexico has a length of approximately 2,500
              km. The coastal pl ai n has a wi dth varyi ng from 30 to 150 km. The coastal rel i ef
              generally is even and low, being traversed by more than 25 important rivers and
              incorporating 23 coastal lagoons of very different sizes. The coastal inlets
              are very important owing to the different transitions between the barrier
              i sl ands, ri ver mouths, and del tas, 1 i nki ng f 1 oodpl ai ns, 1 agoons, marshes, swamps ,
              and mangroves.

                   The rocky coasts appear in short sections and are of low altitude; some
              are composed of compact volcanic rocks forming isolated promontories on the
              general coastal outline. On the Caribbean margin, the coast is rectilinear and

                                                      472










                                                                              Ortiz, et al.

         rocky with short sections of indented configuration.      Escarpments are low and
         formed in calcareous rocks incorporating a narrow abrasion and accumulation
         platform, isolated from the open sea by a coral barrier.

              The predominant types of coast are sandy beaches (1,629 km), followed by the
         swampy coast and marshes (389 km), very important around the estuaries and
         lagoons; the rocky coast has a length of 382 km.

         Climate

              The regional climatic characteristics of the Mexican Gulf Coast are the
         dominant pluviometric system and the yearly temperature distribution (Garcia,
         1989). Garcia divides these elements into three broad zones that from north to
         south are as follows:

              ï¿½  The Tamaulipas northern coast, which is hot and arid, characterized by
                 temperatures higher than 18*C during all the year, with a yearly rainfall
                 of less than 800 km.     Seasonally, it has an extreme climate, with a
                 yearly thermal range of more than 140C. During the winter it receives
                 cold wind masses and during summer torrential rains associated with
                 cyclones or tropical storms.

              ï¿½  The central.part of the littoral is subhumid toward the north and humid
                 at the south, with an average yearly temperature that varies from 220C
                 to 26*C and a yearly rainfall between 1,000 and 1,500 mm, increasing to
                 the south. During the winter the coast receives north winds, that is,
                 cold wind masses, and during autumn, the easterly tropical waves are
                 common. The rest of the year the trade winds are dominant.

              ï¿½  The southeast section comprises the complete Yucatan Peninsula. It has
                 a circulation system similar to the above, with the exception of the
                 temporary stationary high pressure cell over the south-central section
                 of the gulf.    The high pressure cell is responsible for a series of
                 climatic zones that vary from a dry semiarid condition at the northwest
                 end of the peninsula to a subhumid climate toward the south and
                 southwest interior.

              The gulf is a favorable area for tropical cyclones and their accompanying
         floods and storm tides (Jauregui, 1967). Almost 35% of the cyclones originating
         in the Caribbean Sea touch or cross the Mexican coasts. Winters contribute storm
         waves caused by the north winds, in addition to the frontal rains and orographic
         rainfall created when the humid air masses collide with the slope of the Sierra
         Madre.

         Waves and Currents

              Three types of wave regimes are found at the Gulf of Mexico and the
         Caribbean coast (Lankford, 1977):

                 waves and storm surge associated with the tropical cyclones;

                                                 473










              North America

                   ï¿½ waves and storm surge associated with the movement of polar wind masses
                     known in Mexico as north winds (Nortes); and

                   ï¿½ waves and wind surge that is generated within the limited fetch of the
                     gulf basin.

                   The dominant winds show a preference for directions from the northeast,
              east, and southeast quadrants. The wind waves typically have short periods of
              between 5 and 7 seconds, and the average heights are of 2.3, 2.3, and 1.4 m from
              the northwest, north, and northeast, respectively (Lankford, 1977). In general
              terms they can be considered as intermediate to low energy waves, except for the
              north wind and hurricane situations, where waves of more than 4.5 m have been
              observed.

                   The hurricanes occur in the summer, causing intense storms. The cyclonic
              paths show a preference in their course for the Yucatan Peninsula and its
              platform, crossing it, and more frequently approaching the northwest coast than
              the southwest coast.

                   The Nortes develop between October and February. Each year between 15 and
              20 Norte events occur, each one with a duration of 1 to 5 days. It is frequent
              that they exceed 100 km/hr, creating storm tides that inundate lowlands, erode
              the shores, and transfer sediment in numerous directions. There is a movement
              of sands in the dune fields, with an orientation from north to south, prograding
              the coastal lagoons to the lee.

              Cultural and Economic Features

              Demography

                   The coastal zone of the Gulf of Mexico is shared by six states of the
              Federation: Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan, and Quintana Roo,
              with a total of 57 municipalities which together in 1980 had a population of 2.8
              million, representing the 4.1% of the total population of the country (Table 1).

                   Even though the Gulf of Mexico coastal zone has a long tradition of human
              settlement, at present it does not have a dense population. In recent decades
              there is a slight tendency toward an increasing population, especially in the
              urban areas. In the year 2000, it is estimated that the coastal zone will record
              a population of 4.5 million inhabitants, that is, 4.7% of the total population
              of the country.

              Distribution of Human Settlements

                   Of the 2.8 million coastal inhabitants in 1980, 70% lived at an altitude
              between I m and 5 m, mainly along the coast or at river borders very near their
              mouths. About 60% of the coastal population reside in cities (Table 2); 44.9%
              live in cities with more than 100,000 inhabitants.




                                                    474










                                                                                    Ortiz, et al.

          Table 1. Total Population of Mexico and the Gulf of Mexico Coastal States and
                     of the Coastal Zone, 1960-2000


                Area                   1960          1970        1980           1990       2000


          Country                    34,923,129    48,377,363  66,846,833    78,140,006   1,802,174
          Coastal  States             5,080,858     7,138,668  10,090,396     1,244,617  14,950,947
          % Total  Country                14.55          14.76        15.09       15.93       16.29
          Coastal  Zone               1,236,269     1,864,189    2,792,613    3,526,055   41-303,529
          % Total  Country                  3.54          3.85        4.18          4.51       4.69
          % Total  Coastal  States        24.33         26.11-       27.68        28.33       28.78

          Source: Censos    Generales de Poblacion (1960,      1970, 1980).



          Table 2.' Distribution of the Coastal Zone Population by Size of the Settlement,
                      1980 (Size of the settlement by number of inhabitants)


                                  1-999    1,000-    15,000-   20,000-    more than       Total
                                          14,999     19,999    99,999      100,000


          No. of villages         5,129       194          3          8           6        5,341
          N                        96.0       3.6       0.06      0.02         0.1         100.0
          Total Population      572,937  540,510     54,391    345,597   1,236,337     2,749,772
          M                        20.8      19.7        2.0       12.6       44.9         100.0

          Source: General Population Census (1980).


          Cities

               In general, all the states that constitute the gulf coastal zone have
          important cities (Table 3). There are other smaller cities that during the last
          decades have obtained great importance, registering a high rate of demographic
          growth, such as Ciudad del Carmen in Campeche and Cancun in Quintana Roo.

               Most of the cities with more than 15,000 inhabitants perform harbor
          functions; included here are the largest with the exception of Matamoros.

          Port Facilities

               The region has 56 ports, of which 17 are sea ports and the rest are fluvial
          ports. Major ports are located in the States of Tamaulipas, Veracruz, Tabasco,



                                                     475











               North America

               Table 3. Population of the Cities With More Than 15,000 Inhabitants, 1960-2000


                    City            1950     1960        1970      1980     1990      2000


               Campeche             31272    43874       69506   128434 147551       179263
               Carmen               11603    21164       34656     72489    84016    103631
               Cancun"                                             33273(5)
               Chetumal              7247    12855       23685     56709    64928     80850
               Cozumel               2332      2915        5858    19044    20807     26115
               Tampico              94345    124894     185059   267957    313314    371414
               Matamoros            45846    92327      137749   188745    234697    282108
               Veracruz             101221   153705     230220   305456    415456    511678
               Coatzacoalcos        19501    37300       69753   186129    211255    264489
               Minatitlan           22455    34350       68397   145268    168239    208388
               Tuxpan               16096    23262       33901     56037.   64940     77986
               Alvarado              8840    12548       15792     22633    26109     30571
               Panuco                6615      8818      14277     26652    30483     37040
               Gtz. Zamora           4480      6518        9099    15037    17347     20772
               Progreso             13339    17060       21352     30183    34190     39672

               Source: General Population    Census  (1950, 1960, 1970,   1980).
               4It was not possible to make a projection of the Cancun population, because it
               is of recent creation and has no population register for the period 1950-1970.



               and on the coast of the Yucatan Peninsula. The gulf coastal zone is important
               because of the petroleum industry, both in production as well as in processing.
               From the coastal zone of Tamaulipas, Veracruz, Tabasco, and Campeche is extracted
               most of the Mexican oil. In 1985 the zone had 370 fields (S.P.P. 1986, p. 88-
               110). The processing industry is represented by petrochemical refineries. The
               most important petrochemical complex is Coatzacoalcos-Pajaritos-Minatitlan-
               Cosoleacaque-Cangrejera; it is primarily located along the lower Coatzacoalcos
               River.   The complex has 33 petrochemical plants:         12 in Cosoleacaque, 11 in
               Minatitlan, 13 in Pajaritos, and 21 in Cangrejera.        It also has a refinery in
               Minatitlan, with a capacity of 258 thousand barrels per day.

                   In 1985, this complex, together with the one at Ciudad Madero, also located
               in the gulf coastal zone, had the highest production in the country.                The
               production obtained was 968 million barrels of crude oil and 1,186,667 million
               cubic feet of natural gas (S.P.P. 1986, p.47), representing 98.1% and 90.2%,
               respectively, of the total production         in the country.        With regard to
               petrochemicals, in 1984 the production of refined oil was 200 million barrels
               and petrochemicals amounted to 8.5 million metric tons; that is 41% and 74% of
               the yield in the country.

                   Equally important is the oil-line and gas-line net in the State of Tabasco
               that starts at the Sonda de Campeche with a terminal at the port of Dos Bocas.

                                                        476










                                                                            Ortiz, et al.

         Also, Campeche has the majority of maritime production platforms in the Gulf of
         Mexico, with a total of 48 (Ecodevelopment, 1988).

             Recently the first nuclear electric plant at Laguna Verde started to
         function. It is located on the Veracruz coast 70 km northeast of Veracruz. The
         plant has two units, each one with a capacity of 654,000 kilowatts.

             Even though the gulf coastal zone and the Mexican Caribbean have had an
         uneven touristic development, it is important to point out the touristic
         installations exist in some points of this region.    Located in the Caribbean,
         Cancun is the principal touristic node.    In only one decade it has risen to
         become the most important tourist site in the country. Its development has been
         totally planned. It was principally created to satisfy an international demand.
         In 1988 it was able to offer lodging in 9,520 rooms.

             Veracruz and Cozumel are also considered to be important touristic centers.
         In 1988 they were able to offer 4,400 and 2,320 rooms respectively.      Veracruz
         covers principally the demand for national tourism, while Cozumel is important
         for international tourism.

             The ports and installations mentioned having the greatest exposure to
         effects caused by the sea level increase are Tampico, Alvarado, Coatzacoalcos,
         Dos Bocas, Frontera, and Ciudad del Carmen.    Each has an altitude that varies
         between 0 and 3 meters.



         LAND USE

             At the coastal zone, the combination of different elements of the hydrologic
         cycle creates two great natural systems: (1) the coastal lands system and (2)
         the coastal waters system (Toledo, 1984); both are highly productive.

         Use of the Land of the Coastal System

             The use of the land (Table 4) of the first mentioned systems, the coastal
         lands, can also be divided in two:  (1) one of natural origin and (2) the other
         introduced by man.

             In the Tamaulipas coastal strip, dry shrub vegetation is dominant. Forest
         cover is located in wel.1-defined areas, presenting some variants depending of
         the rainfall requirements. A small portion at the northwest and north of the
         Yucatan Peninsula completely lacks vegetation.

             Among the land uses introduced by man, one is extensive cattle raising that
         takes great advantage of the natural pasture characteristic of the zones. New
         pastures that have technically modified some ecosystems as the forest have also
         been introduced. The use of the land for natural and induced pasture covers the
         largest surface area (25%) of the coastal zone. Most of the cattle production
         in the zone is destined for the internal market, principally in the central part
         of the country.

                                               477










               North America

                     Table 4. Use of the Land in the Coastal Zone of the Gulf of Mexico


                 Use of the Land                 Surface in kM2                    Percentage

                                          Partial             Total             Partial   Total


               Pasture ground                                  12167                      25.0

               Bush                          6257                                         12.9
                 Tamaulipas Bush              375                                0.8
                 Mesquite                    1278                                2.6
                 Rosettophyle Bush           1809                                3.8
                 Cacicuale Bush              2795                                5.7

               Forest                                          10011                      22.5
                 Low Perennifoil              979                                2.0
                 High Subperennifoil         7335                               15.0
                 Medium Subperennifoil       1118                                2.3
                 Low Subperennifoil          1558                                3.2

               Savanna                                        4365                         8.9

               Mangrove                                       4504                         9.2

               Tular and popal                                5685                        11.6

               Agriculture                                    4542                         9.3
                 Temporal                    3472                               7.1
                 Irrigation                  1070                               2.2

               Without irrigation             316                                          0.6

               Total                        48826                                         100.0



                   Of less importance is the use of the agricultural land in its two forms,
               natural and irrigated. For the latter, the most important zone is located at
               the north of the coastal region (Tamaulipas) near the U.S. border, principally
               dedicated to the cultivation of cereals.       In non-irrigated agriculture, the
               commercial monocultivation plantings (sugarcane and bananas) are located
               principally in Veracruz and Tabasco.

               Use of the Coastal Waters System

                   The water system is one of the most important systems in the coastal zone
               for its fragility as well as for its ecologic conditions, and because it is
               highly productive. It can be divided into two subsystems, both intimately tied

                                                       478










                                                                             Ortiz, et al.

         through physiographic and ecologic processes in a way that -- on one hand --
         there is the vegetation typical of the system (mangrove, Tular, and Popal) and
            on the other hand -- there are the waters.

             The mangrove is principally limited at the border of the coastal lagoons and
         in the mouths of the rivers. The most important associations are located in the
         Tabasco and Campeche littorals.     The red mangrove is characteristic of this
         community, reaching heights up to 25 meters; it is used for marine construction
         and in the manufacture of charcoal (Ecodevelopment Center, 1988).

             The Popal, or marsh, consists of an association of hydrophyte    *s, including
         Thalia, Cyperus, Colathea, and Heliconia. Very often, it is found together with
         tulares. The greatest extension of this type of vegetation is located at the
         south of Veracruz and in Tabasco. Commonly it is burned during the dry season
         to take advantage of the land for cultivation.

         Economic Importance of the Coastal Zone

             The Gulf of Mexico coastal zone has played an important part in the
         development of the country.     At the beginning of the 20th century, it was
         distinguished for plantation agriculture (sugarcane, banana, and sisal, among
         others).    Later, it acquired importance for commercial cattle raising,
         principally for the internal markets. During the last decades, the oil industry
         has become the most relevant economic activity.     It is important to point out
         that the coastal states (Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan, and
         Quintana Roo) contribute 14.7% of the gross internal product of the country, and
         the coastal zone contributes 3.9%.

             At present, plantation agriculture is still the most important in the
         coastal zone (INEGI, 1985). The region contributes 47.3% of the sugar production
         in the country. Of importance is the irrigation agriculture, especially in the
         coastal plain of the State of Tamaulipas that produced 41.5% of the national
         sorghum that year.

             Cattle raising has been acquiring great importance, principally the breeding
         of bovine cattle. The region had 26.4% of the national production of this type
         of cattle in 1983. But, undoubtedly, the oil industry has distinguished this
         region for its crude production as well as for petrochemicals (see industrial
         installations).


         FISHING

             The Gulf of Mexico and the Caribbean coastal zone with its 2805 km of
         coastline, its 771,500 km2 of exclusive economic zone, and a broad continental
         shelf, represent a significant fishing zone, even though not the most important
         in the country. Outstanding within the region are the Campeche sound and some
         tropical fisheries.



                                                479











             North America

                  Fishing in the region, even though limited prjnc,@pally to the littoral zone,
             including the coastal lagoon systems, is also carried out in the shelf.         The
             State of Campeche has excelled in this type of fishing. As a whole, the zone
             had a 1983 production' of 275,493 tons (INEGI, 1985).
                  When studying the fisheries of the region,      'reat differences are noted
                                                                 9
             between the Gulf of Mexico and the Caribbean.. The-first presents a sustained
             production, carried out principally on the continental platform. In 1983, it
             registered a value of production of 3,842,141 million pesos. The most important
             species captured are shrimp, oyster, clam, crab,, sea fish, mullet, and snook.
             In the Caribbean zone, even though the fishing activity is not so important, some
             fisheries have developed that have economic importance (snail and lobster). The
             value of the fishing production of the zone represented in 1983 a value of 7576.5
             million pesos. Among the fisheries of the region, the most important are the
             following:

             Shrimp

                  Shrimp represent a great economic value,,,and    a considerable part of the
             production is exported. Shrimp from the Gulf of Mexico have a benthic habitat;
             they are distributed from the littoral lagoons up to, 200 meters depth on the
             continental platform    (Ecodevelopment, 1988).   According to the catch figures
             for 1985, the Gulf of Mexico littoral contributed 25,149 ton ,s, which represented
             33.8% of the national production (Secretaria & -Pesca, 1977).        In 1984, 100
             shrimp cooperatives were registered, with bigger vessels destined to catch shrimp
             in the open sea.     Seventy-nine cooperatives , shrimped in the estuaries and
             lagoons. The former reported 76.9% of the shrimp production and the latter 23.1%
             (op.cit.). Most of the estuary shrimp are obtained at Laguna Madre and Tamiahua
             Lagoon (97.2%).

             Oysters

                  The oyster resource commercially exploited in-the Gulf of Mexico's littoral
             is principally the sand bank oyster or American.oyster (Crassostrea virginica)
             and, of less importance, the mangle oyster (Crassostrea rhizophora).

                  The oyster fisheries that have developed in the Gulf of Mexico's littoral
             are the most important in the country; 96% of the national production originates
             from them. The principal oyster fisheries are located in the following coastal
             lagoons:   Laguna Madre, Laguna de Pueblo Viejo, Tamiahua, Lagunas Carmen and
             Machona, and Laguna de Terminos.

                  In the Gulf of Mexico, 52 cooperative societies exploit the oyster, but only
             11 of them register 80% of the total production. Together, the 52 cooperatives
             employ approximately 15,000 fishermen.






                                                    480.










                                                                             Ortiz, et al.

         GOVERNMENTAL RESPONSES TO COASTAL ENVIRONMENTAL PROBLEMS

         Social Context

              The developing countries present numerous problems, which in some instances
         become more serious because of the inadequate handling of the resources they
         have. A clear example of this situation are the Mexican shores of the Gulf of
         Mexico and the Caribbean.

              Recently, the region has registered a remarkable economic growth.       Going
         from an almost isolated rural region, commercial cattle raising, tropical
         plantations, the petroleum activity, and tourism have dramatically altered the
         landscape.

              One can question whether these changes have been for the better.          The
         development of the region has often proceeded as if the only objective is to
         maximize current revenues without regard for the future. The economic growth
         of the region has had high social and environmental costs. Toledo (1984), for
         example, argues that petroleum exploitation is responsible for a substantial
         degradation of the environment.      Similarly, the extensive growth of cattle
         raising and agriculture has been at the expense of the natural vegetation.

              Even though the area has registered an accelerated economic growth, much of
         the population receives no benefit; many people are economically marginal,
         performing economic activities in the traditional way, in large part because the
         people inhabiting the coastal regions are not trained to compete within the new
         labor markets. Yet the introduction of the new economical activities has greatly
         altered their standard of living.

              Another aspect that characterizes the urban development of the region is
         the spontaneous settlements, principally inhabited by people left behind by
         economic development.     Nolasco (1979) estimates that for the year 1990,
         Coatzacoalcos and Minatitlan will have a "marginal." population of 182,488 and
         123,931 inhabitants, respectively, representing 86% and 73% of the total
         population.    This enormous population is not only marginal socially and
         economically within the urban space, but it is spatially relegated to those
         places with the most adverse physical conditions for urbanization, potentially
         the most exposed to the negative effects of sea level rise.

         Environmental Regulation

              Given the threat to coastal environments, Mexico has taken some measures
         -- but because they were started too late, they have a corrective more than a
         preventive character.

              One of the first actions was the Federal Law to Prevent and Control
         Environmental Pollution, issued in 1971.       For the first time, the Mexican
         Legislature considered the importance of controlling the environmental
         deterioration and created offices to enforce environmental laws.


                                                481











             North America

                  However, it was not until 1980 that important steps were taken to protect
             the environment. In 1981, the Public Works Law was issued, which required those
             planning the construction of buildings to consider the environmental impact.

                  In 1982, the Federal Protection of the Environment Law entered into effect
             and with it important advances were obtained, even though the scope was confined
             to controlling air and water pollution.     In 1988, the General Law of Ecologic
             Balance and Environmental Protection brought remarkable changes in how Mexican
             institutions conceptualized problem.      Under this law, regulations have been
             developed that focus on the entire ecology, considering conservation,
             restoration, and improvement of the environment, as well as on the protection
             of natural areas, flora, and fauna (wild and aquatic). Also, the new law refers
             to the reasonable utilization of the natural elements, encouraging estimates of
             the economic benefits of protecting ecosystems and preventing air, water, and
             soil pollution.                                      I

                  This  law   defines   "environmental   impact"   to   include    environmental
             modification caused by human or natural action. Thus it would appear to require
             consideration of sea level rise due both  to natural factors and to the greenhouse
             effect.   Currently, implementation has centered only on the impacts of human
             activities.     Even under this more restrictive interpretation, however,
             considering sea level rise appears to be required, since the environmental
             implications of new projects will be different if sea level rises.               The
             Secretaria de Desarrollo Urbano y Ecologia (SEDUE)-Urban Development Ecology
             Department is currently in charge of evaluating the environmental pollution.

                  At this point, one might ask who makes the decisions in the management of
             the Mexican littoral zone.     In accordance with Merino and Sorensen (1988), a
             great number of jurisdictions and powers on the littoral are identified, but
             unfortunately there is no integrating program for the coast.

                  Table 5 shows the many agencies involved in coastal zone management; the
             vast majority of these offices are managed by the federal government.           This
             condition is one of the main difficulties confronted within a coastal zone in
             carrying out integrated planning.     Although the Committees in Charge of the
             Planning and Development of the States (Coplades) theoretically carry out a
             coordinated effort, a lack of administrative coordination is observed in
             practice. The same condition is also observed among the federal agencies.

                  According to Merino (1988), there are five types of impediments to an
             integrated management of the coast: (1) lack of proper identification of the
             problem; (2) scant coordination among government agencies; (3) lack of economic
             means; (4) lack of continuity and governmental inefficiency; and (5) improper
             knowledge of resources and ecosystems. These problems apply to sea level rise
             as well as to other coastal problems.

                  We would add two other impediments to that list. First, like most of the
             other countries represented in this report, there is a lack of environmental
             education and public awareness in Mexico of the implications of the many threats
             to the ecology. Moreover, one must consider the environment within the context

                                                     482.










                                                                                                                     Ortiz, et al.

              Table 5. Government Agencies With Powers or Mandates Over the Coastal Zone
          ----------------------------------------------                                                   -------------------- ---
          Government         Government                                                                   Attributes
          Level              Agency                       Abbreviation        English Name                and Functions

          ---------------------------------------                                                             ----------------------
          Federal            Secretaria de                SPP                 Budget and Programming      Approval of plans and
                             Programaci6n y                                   Ministry                    budgets of other ministeries
                             Presupuesto
          Federal            Secretarfa de Desarrollo     SEDUE               Urban Development and       Control of urban centers,
                             Urbano y Ecologia                                Ecology Ministry            environmental regulations,
                                                                                                          creation and management of
                                                                                                          park and reserves, control over
                                                                                                          the ZFIVIT-


          Federal            Secretaria de Energia        SEMIP               Energy, Mines and           Control over oil and mineral
                             Minus e Industria                                State Industries            extraction.
                             Paraestatal                                      Ministry

          Federal            Secretaria de Pesca          SEPES               Fishing Industry            Fisheries regulation and
                                                                                                          promotion.

          Federal            Secretaria de Marina         SM                  Marine Ministry             Coastal and oceanic surveillance.
                                                                                                          Contingency facing management.

          Federal            Secretarfa de Turismo        SECTUR              Tourism Ministry            Tourism promotion and
                                                                                                          development plans in touristic
                                                                                                          areas.


          Federal            Secretaria de                SCT                 Communications              Construction and operation
                             Comunicaci6n y                                   Transport Ministry          of ports and navigation
                             Transporte                                                                   services.

          Federal            Secretaria de                SG                  Ministry of the Interior    Control over islands and their
                             Gobernaci6n                                                                  underwater platforms.

          Federal            Secretaria de Relaciones     SRE                 Ministry of Foreign         Pennits and concessions on
                                                                              Affairs                     foreign activities on the coastal
                                                                                                          and Exclusive Economic Zones.


          Federal            SecretarfadeAgricultura SARH                     Agriculture and Hydraulic   Control over fresh waters, dumps,
                             y Recursos Hidrdulicos                           Resources Ministry          and river discharge.

          State              Comit6s de Plancaci6n        COPLADE             State Development           Development planning for
          Federal            del los Estados                                  Planning Committees         the state, coordination between
                                                                              (one for each State)        federal and state governments.

          State              Gobiernos de los Estados                         State Governments           General planning and definition
                                                                                                          of the state priorities.

          Municipal          Gobierno Municipal                               Municipal Governments       Local actions and powers.

          ------------------------
                                                                          483
          Table taken from Merino (1987).











              North America

              of other priorities. Mexico has serious economic problems, and the attention
              of policy makers is focused on activities that generate foreign exchange such
              as oil production.      Although this is a reasonable response to the financial
              crisis, one must hot lose sight of the fact that people's well-being does not
              depend on economic activities alone.


              CONCLUSION

                   The gulf coastal plain is a very important part of the cultural, natural,
              and economic base of the Mexican nation. It is already being affected by the
              encroachment of the sea into the coastal plain. Some of the features can absorb
              the changes and retain most of their characteristics, albeit after a landward
              migration. However, many other features are suffering the many impacts of human
              interference with natural processes, with pollution, and a deteriorating natural
              system. The impacts of a rising sea level are yet another negative element that
              has to be absorbed along with the others. The combination of sediment deficits,
              subsidence, and coastal pollution is magnifying the effects of sea level rise.

                  The causes of the problem are not simple, nor will the solution be simple.
              It will be difficult to command the attention of policy makers faced with more
              pressing economic and social problems. Nevertheless, some preparation of sea
              level rise and other consequences of global warming are clearly warranted. The
              general history of environmental protection suggests that a problem must be
              studies for years, sometimes decades, before governments can implement solutions.
              Accordingly, the highest-priority response in Mexico should be for coastal
              environmental scientists and engineers to begin exploring the possible
              consequences. A major conference in Mexico on the topic is clearly warranted.


              BIBLIOGRAPHY

              Contreras, F y L.M. Zabalegui.       1988.   Aprovechamiento del litoral mexicano,
              Centro de Econdesarrollo y Secretaria de Pesca, Mexico.

              Garcia, E.     1988.   Modificaciones al sistema de clasificacion climatica de
              Koppen. Offset Larios, Mexico.

              Garcia, E.    1989.   Mapa de climas, Clave IV-4-10, Atlas Nacional de Mexico,
              Instituto de Geografia, UNAM, Mexico.

              Instituto Nacional de Estadistica Geografia e Informatica. 1985. Anuario de
              Estadisticas Estatales, Mexico.

              Jaurequi, E.    1967.   Las ondas del este y los ciclones tropicales en Mexico,
              Revista de Ingenieria Hidraulica, Vol. XXI, Num 3, Mexico.

              Lankford, R.    1977.   Coastal Lagoons:     Their origin and classification.        In:
              Estuarine Processes.    Wiley, M., ed. New York: Academic Press, pp- 182-215.


                                                        484










                                                                                   Ortiz, et al.

          Merino, M. 1987. The coastal zone of Mexico. Coastal Management 15:27-42.

          Merino, M. and J. Soremsen.         1988.   La zona costera mexicana:         recursos,
          problemas e instituciones, En Ecologia y Conservacion del Delta de los rios
          Usumacinta y Grijalva, Memorias, INIREB, 91-110, Mexico.

          Nolasco, M.       1979.     Ciudades Perdidas de Coatzacoalcos, Minatitlan y
          Cosoleacaque, Centro de Ecodesarrollo, Mexico.

          Psuty, N.P. 1967. The Geomorphology of Beach Ridges in Tabasco, Mexico. Coastal
          Studies Series. Baton Rouge, LA: Louisiana State University Press.

          Secretaria de Pesca.       1987.     Pesquerias Mexicanas:       Estrategias para su
          Administration, Mexico.

          Secretaria de Programacion y Presupuesto.          1981.   Atlas Nacional del Medio
          Fisico, Mexico.

          Secretaria de Programacion y Presupuesto. 1982. X Censo General de Poblacion
          y Vivienda   del Estado de Campeche, Mexico.

          Secretaria   de Programacion y Presupuesto. 1982. X Censo General de Poblacion
          y Vivienda   del Estado de Quintana Roo, Mexico.

          Secretaria   de Programacion y Presupuesto. 1983. X Censo General de Poblacion
          y Vivienda   del Estado de Tabasco, Mexico.

          Secretaria   de Programacion y Presupuesto. 1983. X Censo General de Poblacion
          y Vivienda   del Estado de Tamaulipas, Mexico.

          Secretaria   de Programacion y Presupuesto. 1983. X Censo General de Poblacion
          y Vivienda   del Estado de Veracruz, Mexico.

          Secretaria   de Programacion y Presupuesto. 1983. X Censo General de Poblacion
          y Vivienda   del Estado de Yucatan, Mexico.

          Secretaria   de Programacion y Presupuesto.       1986.   La Industria Petrolera en
          Mexico, Mexico.

          Toledo, Alejandro. 1984. Como destruir el paraiso, El desastre ecologico del
          Sureste, Centro de Ecodesarrollo, Mexico.

          West, R.C., N.P. Psuty, and B.G. Thom.            1969.    The Tabasco Lowlands of
          Southeastern Mexico. Coastal Studies Series. Baton Rouge, LA: Louisiana State
          Univeristy Press.

          Zavala, J.    1988.   Regional izacion. natural   de la zona petrolera de Tabasco,
          Casos de Estudio, INEREB, Mexico.



                                                    485











                   RAISING MIAMI -- A TEST OF POLITICAL WILL



                                            TED MILLER
                                                and
                                          WILLIAM HYMAN
                                      The Urban Institute
                                          Washington, DC




          ABSTRACT

               Miami and the remainder of metropolitan Dade County are built on
          extraordinarily porous water-bearing rock and sand, which lies 1.6 meters below
          the surface, extends down to a depth of 45 meters, and extends out under the
          ocean. Shallow dikes with supplemental pumping will not keep out a rising sea,
          which simply would float the freshwater table up from below. Even though fill
          can be strip-mined on publicly held local lands and transported to the area by
          barge, if the sea level rose one meter, more than $600 million of public
          investment would be required in Dade County to raise streets and improve canals,
          drainage, and pumping, a sum equal to a 1% rise in the local capital budget for
          the next 100 years. Landowners might incur additional costs to raise buildings.
          Even if the investment were made, the county might be more vulnerable to
          hurricane damage.

               The cost estimates given here assume the streets will be raised as they
          are reconstructed, roughly at 35-year intervals. If the county does not raise
          streets in advance of sea level rise, costs incurred as a result of sea level
          rise might be an order of magnitude higher. Increasing construction costs today
          to raise streets above the levels of adjoining lots, however, for the sake of
          future sea level rise will require a good deal of public education and foresight
          from policymakers.


          INTRODUCTION

               This paper uses a case study of Miami to illustrate the likely impacts of
          sea level rise on a major city. Specifically, we examine the impacts that global
          climate change, coupled with sea level rise, could have on Dade County's water
          control and drainage systems, building foundations, roads, bridges, airports,
          sewage transport and treatment systems, and water supply.

               Although it varies in actual practice, the nominal replacement cycle for
          most infrastructure is 30 to 50 years; some water supply investments have 100-


                                                 487











             North America

             year lives. Because communities are essentially locked into capital stock for
             a relatively long time, much of the present infrastructure could be vulnerable
             to rapid climate change.    Sea level rise, temperature change, and changes in
             precipitation patterns, for example, all could alter the balance between water
             supply and demand before much of a community's capital stock is due to be
             replaced.    The nature and pattern of precipitation could affect drainage
             requirements, as well as highway design and maintenance. In addition, household
             relocation in response to climate change could radically alter the population
             growth projections on which capacity decisions about water, highway, and
             wastewater treatment systems are based.
                  The uncertain, yet potentially imminent, impact of global climate change
             already has increased the riskiness of infrastructure investment.          Applying
             design standards and extrapolating from historical data still might not provide
             reasonable assurance that water and power supply, dam strength and capacity,
             bridge underclearances, or storm sewerage capacity will be adequate given the
             long lives of these facilities.

                  The National Flood Insurance Program's maps identifying the 100-year
             floodplain and 500-year floodway will no longer be reliable as a basis for local
             building and zoning ordinances designed to minimize flood losses.

                  Especially in coastal areas, the possibility of accelerated change in global
             climate may soon require careful decisions regarding how and when to adapt the
             infrastructure.      Emphasizing   life-cycle   costing   and   upgrading    during
             reconstruction, in anticipation of future changes,. could yield large, long-term
             cost savings.

                  Corporate investment analysts have developed methods, including decision
             theory, portfolio analysis, and chance-constrained programming, to guide
             decisionmaking under uncertainty.     Infrastructure analysts at all levels of
             government might be wise to adapt these methods to their work.

                  Growing uncertainty about future temperature, precipitation, and sea levels
             might dictate a reassessment of existing standards and safety factors for
             ventilation, drainage, flood protection, facility siting, expansion capability,
             and resistance to corrosion, among others. Prompt identification of inevitable
             changes could allow communities time to adjust design standards based on
             geographic location -- for example, on roadbed depth and home insulation levels
             -- and thus realize significant savings.


             THE METHODOLOGY AND ASSUMPTIONS

                  We assumed that a gradual sea level rise would be managed through strategies
             such as raising the land in low-lying areas, upgrading levees and dikes with
             pumped outflows, retreating selectively from some areas, and increasing the
             freshwater head, roughly in proportion to sea level rise, to prevent saltwater
             intrusion into the aquifer. The case study does not examine how climate change
             might affect beach erosion or discuss related actions that might protect the

                                                    488









                                                                             Miller and Hyman

          developed barrier islands of Miami Beach and Key Biscayne, which largely lie
          within 1 meter of sea level.

               Preliminary analyses and estimates by local engineers and planners,
          undertaken at our req6est, formed the primary basis for the case study. Further
          information was drawn from Rhoads et al. (1987) and from the Comprehensive
          Development Master Plan for Dade County (Metropolitan Dade County Planning
          Department, 1979, 1988).

               Our analyses assumed a I-meter rise in sea level.         The temperature and
          precipitation impacts of global climate change were estimated by applying the
          percentage changes, by season, indicated by two climate change models (Jenne,
          1988), to historical climate data from 1950 to 1980.        The models examine the
          weather changes that might result from an effective doubling in carbon dioxide
          levels. Both the Goddard Institute for Space Studies (GISS) and the Geophysical
          Fluid Dynamics Laboratory (GFDL) models suggest Greater Miami's (essentially Dade
          County's) average temperature could rise from 26*C to 290C (750F to 800F). Both
          models suggest the precipitation level might remain reasonably constant.


          DADE COUNTY'S WATER SUPPLY INFRASTRUCTURE

               Greater Miami exists within an unusually complex environmental setting.
          An intricate water management system already has evolved to protect the area
          against flooding, to provide freshwater, to irrigate nearby agricultural lands,
          and to limit saltwater intrusion, which could harm the Everglades National Park
          and contaminate much of the potable water supply.             The effects on the
          infrastructure of an effective doubling in carbon dioxide will be shaped by the
          hydrology and existing water management system.

               Miami is a hydrologic masterwork, a densely populated area bounded by water
          from below and on all sides.      When the city was first developed, the entire
          southern tip of Florida was a mangrove swamp called the Everglades or River of
          Grass.   The Everglades often was awash in freshwater.      The initial settlement
          was built on local high points of the Atlantic Coastal Ridge, 10 to 23 feet
          above sea level, and immediately adjacent to Biscayne Bay and the Atlantic Ocean.

               Today, most of Greater Miami is on lower ground.        It was made habitable
          through drainage and reclamation (Metropolitan    Dade County Planning Department,
          1979). Water drainage from the Kissimmee River    Basin and Lake Okeechobee begins
          northwest of Miami and runs through canals to     Miami and other coastal cities.
          To the northwest are three water conservation     areas used in the South Florida
          water management system. South and west of the    inhabited area is the Everglades
          National Park, a unique ecology. On the east,     Miami is bounded by the Biscayne
          Bay and the Atlantic Ocean.

               Just a few feet below Miami's surface lies the Biscayne Aquifer, the major
          freshwater supply for the area. Maps in the Dade County Comprehensive Plan show
          that the height of the water table varies by about 3 feet between seasons, but
          exceeds sea level in most of the aquifer. The water table is very close to the

                                                  489










              North America

              surface except along the high points of the Atlantic Ridge.    In the wet season,
              water flows less than 5 feet below 34% of Miami streets (measured by Dan Brenner,
              Assistant Highway Engineer, City of Miami Department of Public Works, 1986).

                   The Biscayne Aquifer is wedge-shaped.     It is 100 to 200 feet deep along
              and below Biscayne Bay and averages 100 feet in depth in the developed area.
              West of the city, it falls off rapidly and ends near the Dade County line.
              Because of the aquifer's shape, much of the water can be tapped only by wells
              dug in or just west of Miami.

                   The seaward edge of the aquifer is saltwater. In many cases, the cone of
              depression for the wells comes close to the salt line in the dry season. Since
              the 1940s, Miami has used freshwater pressure to prevent further saltwater
              intrusion into the aquifer. Currently, control structures and canals are used
              to create a 2- to 3-foot head differential (Metropolitan Dade County Planning
              Department, 1979).   As a result, there is saltwater intrusion from 0.25 to 2
              miles inland in the developed areas and about 5 miles in the Everglades National
              Park where the aquifer is shallower.

                   The Biscayne Aquifer is one of the most permeable in the world, an
              extraordinarily transmissive layering of sand, solution-riddled limestone, and
              sandy limestone roughly 100 times more permeable than packed sand (Metropolitan
              Dade County Planning Department, 1979).     Wellfields are recharged simply by
              channeling water across the aquifer and letting it percolate down (South Florida
              Water Management District, 1987). The height above sea level and groundwater
              discharge areas of the aquifer change constantly in response to such relatively
              minor factors as rainfall and tides (Metropolitan Dade County Planning
              Department, 1979).

                   Because of Miami's high temperatures7, reduced evaporation loss makes the
              Biscayne Aquifer a much better place than shallow surface lakes to store water
              for use in the dry season (Metropolitan Dade County Planning Department, 1979).
              Furthermore, overuse of surface storage would destroy the unique Everglades
              ecology, which requires cyclic drying.

                   In the remainder of this paper, we present the case study results.
              Specifically, we discuss Dade County's possible responses to sea level rise; how
              the various parts of the infrastructure could expect to fare and what
              improvements might have to be made; and what the costs of climate change/sea
              level rise are likely to be.


              HOW WILL DADE COUNTY RESPOND TO SEA LEVEL RISE?

              Because of the Porous Aquifer, Diking Alone Will Not Control Sea Level Rise

                   In most.coastal communities, the major challenge of a I-meter rise in sea
              level would be to control surface inundation. The solution in both New Orleans
              and the Netherlands has been to dike the water at the surface and pump out the
              modest seepage into ditches behind the dikes.

                                                     490









                                                                            Miller and Hyman

                To apply this approach in Miami would require building a dike that holds
           water back for the entire depth of the Biscayne Aquifer. Essentially, a water-
           impermeable barrier would be needed along the length of Broward and Dade Counties
           to a depth of 100 to 150 feet. Otherwise, the pressure of the seawater would
           cause it to rush into the aquifer below the surface and push the freshwater in
           the aquifer up more than 3 feet, raising it very close to the surface. If the
           freshwater were pumped out, it gradually would be replaced by saltwater and the
           freshwater storage capacity of the aquifer would be lost.

           Raising Land and Increasing the Freshwater Head Might Be Primary Responses

                A very preliminary analysis suggests two primary responses to sea level
           rise. First, raise the land in low areas rather than trying to dike. Second,
           increase the freshwater head roughly in proportion to sea level rise, thus
           maintaining the freshwater storage capacity of the aquifer. The latter method
           will not raise the water table notably more than sea level rise alone.

                Thus, if sea level rose 3.3 feet, Miami might raise its freshwater head by
           2 to 3 feet to control the infiltration of subsurface seawater into the aquifer,
           as well as raise or build surface levees and add pumping capacity in developed
           low-lying sections.   Even this approach might not work because the necessary
           water may not be available, especially during droughts. According to the Dade
           County master planning staff, Miami could face a water supply deficit in the 21st
           century. The most practical solution to the shortage would be to purify sewage
           effluent for use in cooling towers and for lawn watering, or to desalinate water
           at three times the cost.

                  For the purposes of this report, consistent with Rhoads (1987), we have
           assumed that selective retreat, levees with pumped outflows in selected low-
           lying areas, and elevation of some facilities and structures, as well as an
           increase in the freshwater head to protect the aquifer, would be the most cost-
           effective combination solution on the mainland.        For a discussion of the
           appropriate intervention for Miami Beach and other developed barrier islands,
           primarily beach nourishment, consult Leatherman (1989).

           Sea Level Rise May Necessitate Increased Coastal Defense

                In coastal communities such as Miami, sea level rise could stimulate
           extensive upgrading of coastal defense structures such as dikes, saltwater guard
           locks, and pumping systems to prevent inundation, erosion, storm surges, and
           reduce saltwater intrusion into aquifers and rivers. Currently, these structures
           are such a minor category of infrastructure that they are not inventoried or
           included in needs assessments.

                A 1-meter rise in sea level would not inundate much of the developed Miami
           mainland, although it would increase considerably the risk of flooding,
           especially during hurricanes. One area at risk of inundation is the large, low-
           lying area south of Miami, a low-density residential area built on land reclaimed
           by adding fill. Levees and water control structures used for flood protection
           in these areas should prevent inundation if they are upgraded. Structures in

                                                  491











              North America

              these areas generally sit on piles and fill already raised 1 to 1.5 meters above
              the land surface to reduce flood risks.

                   Dade County's water management system includes about 1,000 kilometers of
              canals, 400 kilometers of levees, and 30 control structures (Metropolitan Dade
              County Planning Department, 1979).     It seems unlikely that the canals would
              require rebuilding, but they might have to be dredged more frequently.          The
              levees (dikes) probably would be raised in selected areas, which can only be
              identified through detailed studies. Robert Hamrick at the South Florida Water
              Management District estimates it could cost approximately $7,000 per linear
              kilometer to raise the levees 60 centimeters with mounds of crushed limestone,
              which is extensively quarried in local open pits. The fill is scooped from a
              copious supply that lies virtually at the surface on public lands, and then is
              loaded on flat-bottomed barges and sprayed onto the tops of the levees.
              Interpolating from the analysis in Weggel (1989), we estimate that $60 million
              could be spent on canal and levee improvements if sea level rose 1 meter over
              the next 100 years. Hamrick also suspects that the 30 control structures in Dade
              County would be redesigned and replaced at an estimated cost of $1.6 million
              each, a total of $48 million in 1988 dollars.

                   The current water management system relies mainly on gravity drainage.
              With sea level rise, much pumping capacity might have to be added to prevent
              subsurface saltwater intrusion.. Both the capital and operating costs could be
              large.


              HOW WILL THE PRESENT INFRASTRUCTURE FARE?

              Building Foundations Are Adequate

                   A preliminary examination of the structural stability of footings and
              pilings suggests that buildings are not likely to suffer structural instability
              from a 1-meter rise in the water table.     When a building is on coral rock or
              I imestone, concrete footings with reinforcing steel frequently provide structural
              support. A monolithic slab with flared ends to a depth of 45 to 60 centimeters
              is a typical foundation for a residence, since most residential structures and
              commercial buildings are too close to the water table to have basements. Larger
              residences might have both seatings and footings.      Tall buildings, including
              residential condos, are most likely to rest on piles, although other techniques,
              including spread footings and compacting, are used to provide structural support.

                   Flooding raises little possibility of structural instability due to settling
              or foundation cracking, for example, because the foundations are overdesigned
              by a factor of 1.5 to 2.0, according to engineers at Florida Atlantic University.
              Currently, regulations and permitting procedures, including Dade County Flood
              Criteria and criteria of the National Flood Insurance Program, require most new
              construction to be on raised lots to prevent flood damage.




                                                      492









                                                                             Miller and Hyman

           One-Third of the Streets Might Need To Be Raised

                A typical city street consists of a 4-centimeter layer of asphalt
           constructed over a 20-centimeter lime rock base. Beneath the base is a subgrade,
           with its top 15 centimeters compacted to a minimum of 95% of its maximum density.
           If the sea level and water table rose roughly 1 meter, given the annual
           fluctuations in the water table and its proximity to the surface, the subgrade
           and base of many city streets would be subject to a certain amount of saturation.
           Complete structural failure would occur if a heavy load were to pass over the
           surface. To prevent collapse, vulnerable streets would have to be raised by 1
           meter.

                Dan Brenner of the City of Miami Department of Public Works estimates that
           approximately 34% of street and highway mileage -- 400 kilometers -- is 1.5
           meters or less above the water table.        Raising streets by I meter during
           reconstruction, according to the Department of Public Works, would cost between
           $450 and $55 per linear meter (remember that fill is cheap) with minimally
           improved transitions to adjacent properties. Reconstructing the 400 kilometers
           to adjust for a I-meter rise in sea level could add roughly $237 million to the
           $1.4 billion reconstruction cost of these projects. If a 2.5% rate were used
           to compute further costs, expected costs would be minimized by raising a Miami
           street even though the subbase clearly would not be affected by sea level rise
           in the next 10 years, but as long as there were a 38% or greater chance that sea
           level rise would be substantial enough to affect the subbase after 10 years.
           (This cost estimate for raising streets omits substantial private costs for
           better drainage, raising of some yards (especially at newer buildings where the
           structure itself already is raised), raising lots at reconstruction, and positive
           sewage pumping from the houses to the mains in some areas.)

                If sea level rise required streets and buildings to be raised, the
           connectors from buildings to the sewer interceptors also would have to be
           rebuilt.   Pump stations also might have to be raised and modified to maintain
           the same driving force (differential in inside versus outside pressure), and
           overflow structures might need to be improved.

                In the City of Miami, the costs of adapting elevated houses and other
           building connections to existing sewer lines would be the responsibility of
           private property owners. The remainder of the costs would be public. The Miami
           Department of Public Works estimates that the costs to raise and modify pump
           stations, modify overflow structures and miscellaneous appurtenances, and raise
           manholes alone could be $8 million.

                The aesthetic and drainage impacts of raising streets could be dramatic.
           Except for recently constructed houses (which often are raised to meet flood
           ordinances), people's houses, yards, and garages would be 1 meter below the
           streets (and canals), a situation strongly reminiscent of the Dutch countryside.
           Some yards and houses surely might be raised when they are reconstructed, and
           yards might be raised or flanked by covered exfiltration trenches. Fortunately,
           there are no basements.



                                                  493











              North America

              Many Causeways and Bridges Could Be Raised at Reconstruction

                   The causeways running from Miami across Biscayne Bay to Miami Beach are
              between 1.5 and 3 meters above sea level and might be at risk of structural
              weakening and failure.      They also would be Vulnerable if higher sea level
              increased hurricane storm surges. These potential impacts could be avoided if
              reconstruction* over the next 100 years used design features to mitigate the
              effects of sea level rise. On the other hand, if modifications were not made
              during    reconstruction, the cost of retrofitting the bridges could be
              substantially higher.

                   Except for steel drawbridges, most bridges in Miami are constructed of
              concrete and steel, with a life expectancy of 50 years.        Only those near the
              coast have epoxy-coated reinforcing bars, a practice introduced in 1970 to fight
              corrosion. Without remedial action, the effects of sea level rise might include
              the following:

                   ï¿½  Pavement failure in low-elevation bridge approaches.

                   ï¿½  Erosion beneath low-lying bridge abutments and consequent differential
                      settlement, stresses, and strains.

                   ï¿½  Potential lifting of corrugated steel and box culverts.

                   ï¿½  A drop in the elevation of fenders on the piers over navigable waters.
                      (Fenders  protect   against damage- from vessels        bumping   into    the
                      substructure.)

                   ï¿½  Reduced underclearances on navigable waterways.

                   ï¿½  Reduced accessibility inhibiting proper inspection and maintenance.

                   ï¿½  Added wave "slapping action."

                   ï¿½  Increased likelihood of flood   backwaters, particularly for bridges     that
                      have underclearances of 3 to 6 feet over non-navigable waters.

                   Regardless of improvements over   the next 100 years, bridges with piers and
              piles in both Biscayne Bay and in      rivers could experience deeper scouring,
              although the waterflow velocity under non-storm conditions would decrease because
              of the increased water depth. Scouring also could increase if storms became more
              frequent or severe.

              Airports Night Need Better Drainage

                   Miami International Airport is a major international hub.           Located i n
              northwest Miami, its airfields and aprons cover 20 square kilometers. Unlike
              the majority of major commercial airports, most of the surface area is asphalt
              pavement. The aprons are concrete. The asphalt varies in thickness from 5 to
              40 centimeters depending on the base. An extensive drainage system allows storm

                                                      494









                                                                            Ni77er and Hyman

            runoff to empty into ditches by the airfield, then into the Blue Lagoon and the
            Tamiami Canal.  The groundwater elevation ranges from 60-90 centimeters to 1
            meter, runways 2.7 to 3.0 meters, and taxiways and aprons 24 to 27 meters. A
            1-meter rise in groundwater would not flood the pavement or base, but would
            affect drainage retention capacity and exfiltration during a storm. If several
            large pumping stations were constructed to draw down the airport water table at
            the onset of a storm, acceptable operating conditions could be maintained.
            Drainage interconnections and related improvements such as pump stations, dikes,
            and culverts might cost $30 million (Tripp, 1989).

                 The likely impact of sea level rise on one of Miami's wastewater treatment
            facilities, located on Virginia Key, also was assessed. Since Virginia Key has
            no freshwater beneath the surface, intrusion is not an issue.      The treatment
            plants are approximately 3 meters above sea level.       Berms and dikes reach
            elevations of approximately 4 meters, while sterile fill material from the sludge
            plants has accumulated to elevations around 30 feet.        A severe hurricane
            producing higher storm surges still could wash out portions of the island. If
            the activated sludge treatment plants were still in operation as sea level rise
            accelerated, the berms and dikes on the island might have to be raised to prevent
            processed sludge from being washed into Biscayne Bay. Another possible effect
            of a hurricane is that dirt beneath the plant could be washed out, causing the
            piping to collapse.

            Storm Sewers and Drainage Trenches Might Require Major Upgrading

                 Miami relies primarily on localized drainage and canal systems, involving
            exfiltration that carries surface storm water to subsurface groundwater. Highly
            permeable soils make this a cost-effective form of stormwater drainage, except
            in low-lying areas where there are fine soils that do not drain well.       Where
            natural drainage systems are not effective, or tidewaters and easterly winds
            increase the water head pressure at discharge outlets to the bay, a positive
            drainage pipe system is used.

                 Standards for storm sewers vary at the federal, state, and local levels.
            Interstate highway storm sewers are designed for 10-year storms. On arterial
            streets in areas of high population density, 3-year storms serve as the design
            standard. On local streets, Miami's system is designed for a rainfall rate of
            3.75 centimeters per hour. Ponding occurs three or four times per year on local
            streets with this type of storm drainage (City of Miami Department of Public
            Works, 1986).

                 In 1988, Miami started a 12-year, $267 million program to reduce flooding
            and ponding. This program includes constructing 225 kilometers of exfiltration
            trenches at a cost of $105 million, as well as positive drainage construction
            at a cost of $55 million.    These systems are designed to provide protection
            against flooding from 25-year storms (City of Miami Department of Public Works,
            1986).

                 Even with these planned improvements, if sea level rises 1 meter, flooding
            and ponding problems could be worse than they are today, especially because the

                                                   495










              North America

              water table will be closer to the surface. The costs of adequate future flood
              protection almost certainly would be several hundred million dollars.

              Water Supply Might Be Reduced Unless Hurricanes Increase and Demand for
              Electricity Could Increase

                   Miami's water supply could be reduced by water used to prevent saltwater
              infiltration.   Some wellfields almost certainly would have to be relocated
              farther inland. Potentially more important than the actual water expenditure,
              sea level rise would raise the aquifer closer to the surface, putting it within
              easy reach of the roots of more pl ants.     Using evapotranspiration and soil
              moisture models, Rhoads (1987) estimates that soil moisture deficiency
              probabilities could double, assuming no change in rainfall.

                   The warmer temperatures also could raise water demand, most notably for
              commercial cooling towers. Indeed, Linder et al. (1987) project that increased
              air-conditioning needs in south Florida could raise peak electricity demand by
              2 Me.

                   Although the solution to these problems will require detailed study, one
              alternative is to increase capacity to produce desalinated water -- e.g.,       by
              boiling and cooling, reverse osmosis filtration, or some new technology -- or
              to use purified effluent as a backup supply for drought periods.       Full cost
              pricing of this water would encourage greater conservation and thus reduce
              demand. Another complexity requiring study is the need to maintain some water
              in the water conservation areas, since the water containments are designed to
              function with a vegetative lining.

                   The largest uncertainty about water supply is the impact that climate change
              will have on hurricanes. Hurricanes historically have contributed substantially
              to aquifer recharge (Metropolitan Dade County Planning Department, 1979). Rising
              temperatures coul d i ncrease. hurri cane frequency and i ntens i ty - - a mi xed bl ess i ng
              that would ensure an adequate waterl.supply but inflict billions of dollars in
              wind and flood damage.


              POTENTIAL COSTS OF CLIMATE CHANGE30 MIAMI

                   Table I shows that the total costs to make the improvements and repairs
              discussed in the previous section of this paper could easily exceed $600 million.
              The costs could be.much higher if changes in sea level or global climate came
              through abrupt "sawtooth" shifts, making it difficult to adapt infrastructure
              primarily during normal-repair and replacement.

                   The infrastructure costs suggested here are large but not unmanageable.
              We estimate that the costs could be accommodated by increasing annual capital
              spending by I to 2% for the next 100 years.




                                                    496









                                                                              N177er and Hyman

           Table 1.     Probable Infrastructure Needs and Investment in Miami in Response
                        to a Doubling of CO, (millions of 1987 U.S. dollars)


           Infrastructure Needs                         Costs


           Raising canals/levees                        $60
           Canal control structures                     $50
           Pumping                                      not estimated
           Raising streets*                             $250 extra reconstruction cost
           Raising yards                                not estimated
           Pumped sewer connections                     not estimated
           Raising lots at reconstruction               not estimated
           Drainage                                     $200-300
           Airport                                      $30 not estimated; retrofit costs more
                                                        than raising at reconstruction
           Sewer pipe corrosion                         minimal
           Water supply                                 not estimated

               Total                                    $600+


           *Assumes streets will be raised as they are reconstructed, roughly at 35-year
           intervals. If the county does not raise     streets in advance of sea level rise,
           the cost may be an order of magnitude higher.


           THE POLITICS OF ANTICIPATING SEA LEVEL RISE

                Cost-effective adaptation to global climate change will require complex,
           careful decisions about how and when to adapt the infrastructure.         Life-cycle
           costing and expensive upgrading in anticipation of future changes will be
           essential.   To accomplish this will require strong leadership.        It will also
           require careful examination of the available options for controlling the sea.
           Hard political decisions will need to be made concerning how well Dade County
           can afford to protect its coastal exposures and how the costs will be split among
           affected property owners, local governments, the Metropolitan Dade County
           government, the State of Florida, and the Federal Government.

                The economic cost of climate change is not the only expense Miami faces.
           However, local officials also will incur substantial political costs as they
           attempt to meet the impending infrastructure crisis. Suppose Miami chooses the
           most cost-effective course and acts in anticipation of a rising sea. Bridges
           and roads could be raised as they come due for reconstruction.        Water, sewer,
           and drainage facilities could be modified to counteract the effects of an
           anticipated rise in sea level. City officials might have to educate the bond
           market. Raising bridges or streets, for example, could be viewed as
           overbuilding. It could be an uphill battle to convince bond underwriters that
           the city actually was pursuing a strategy that protects investors.

                                                    497










              North America

                   Even if no extra costs were involved, raising streets could prove quite
              controversial. Few people will like looking up at the street from their living
              room windows.   Worse, no one will feel comfortable the first time runoff from
              a hurricane pours down the edge of the streets into drainage ditches in their
              yards. Imagine the hue and cry when some of those ditches overflow.

                   The political price of such pre-emptive action could be high.       Taxpayers
              would be asked to pay extra taxes to help underwrite infrastructure improvements
              because sea level might rise at some uncertain future date.        Given voters'
              general aversion to tax increase of any kind, candidates or elected officials
              pursuing, such a strategy could face problems at the polls.          There would
              undoubtedly be considerable political debate over spending money in anticipation
              of an uncertain event versus using that money to address known current problems.

                   Opposition to anticipatory action might not be the only political reaction.
              Lobbying and political organizing could focus on location issues, that is, what
              parts of the city will be considered priority areas and thus will be the first
              to be protected.

                   Inaction also is politically risky. Imagine voter reaction if nothing is
              done in advance of sea level rise until the transportation system is affected.
              Road collapses make headlines, especially if people are killed as a result.
              Emergency repairs to roads and bridges, even if undertaken before any damage
              occurs, can cause massive traffic delays.      That kind of spending can break
              budgets, as outside contractors are needed to do work that normally would be done
              locally. Emergency raising and rebuilding of the lowest 5% of the streets, one
              seventh of those that might need to be raised before the rise in sea level
              reaches one meter, could cost $240 million at normal construction prices, about
              half the total amount the city spends currently on capital construction. Bridges
              and bridge approaches *would have to be reconstructed simultaneously, adding
              further costs. Raising streets during normal reconstruction would be far less
              disruptive.   Again, unduly massive hurricane damage really could generate
              controversy.

                   Miami officials seem unlikely to take any major anticipatory action on
              global climate change until some precipitating event, possibly a direct hit by
              a major hurricane. Other possible incentives might be revision of engineering
              design standards to require consideration of possible sea level rise, or the
              availability of federal matching funds for planning responses to global climate
              change or for risk-reduction activities.

                   Regardless of the approach Miami officials choose, much public education,
              campaigning, and political acumen will be required. The city faces a long, hard
              row to high ground.







                                                    498









                                                                                 Miller and Hyman

            BIBLIOGRAPHY

            City of Miami Department of Public Works. 1986. Storm Drainage Master Plan,
            Executive Summary, Miami, FL:        City of Miami Department of Public Works,
            September.

            Jenne, R.    1988.   GISS and GFDL Climate Projections.        Denver, CO:     National
            Center for Atmospheric Research.

            Leatherman, S. 1989.     Cost of Defending U.S. Open Coast from Rising Sea Level.
            College Park, MD: University of Maryland.

            Linder, K.P., M.J. Gibbs, and M.R. Inglis. 1987. Potential Impacts of Global
            Climate Change on Electric Utilities. Fairfax, VA: ICF Incorporated.           824-CON-
            AEP-86. December.

            Metropolitan Dade County Planning Department. 1988. Comprehensive Development
            Master Plan for Dade County, Florida.        Miami, FL:    Metropolitan Dade County
            Planning Department. April.

            Metropolitan Dade County Planning Department. 1979. Comprehensive Master Plan
            for Dade County, Florida.         Miami, FL:    Metropolitan Dade County Planning
            Department. July.

            Rhoads, P.B., C.C. Shih, and R.L. Hamrick.          1987.   Water Resource Planning
            Concerns and Changing Climate: A South Florida Perspective.         In Proceedings of
            the Symposium on Climate Change in the Southern United States: Future Impacts
            and Present Policy Issues, conducted by the Science and Public Policy Program,
            University of Oklahoma. Washington, DC: U.S. Environmental Protection Agency,
            pp. 348-363.

            South Florida Water Management District. 1987. Water Resources Data and Related
            Technical Information to Assist Local Government Planning in Dade County. West
            Palm Beach, FL: South Florida Water Management District.

            Tripp, R.    1989.  Personnal communication to the Urban Institute from Howard,
            Needles, Tammen and Bergendoff, 1989.

            Weggel, J.R., S. Brown, J.C. Escajadillo, P. Breen, and E.L. Doheny. 1989. The
            Cost of Defending Developed Shorelines along Sheltered Waters of the United
            States from a Two-Meter Rise in Mean Sea Level. In: The Potential Effects of
            Global Climate Change on the United States.          J. Smith and D. Tirpak, eds.
            Washington, DC: U.S. Environmental Protection Agency.








                                                      499










                ACCOMMODATING SEA LEVEL RISE IN DEVELOPING WATER
                                          RESOURCE PROJECTS


                                        ROBERT H. SCHROEDER, JR.
                                        Chief, Planning Division
                                      U.S. Army Corps of Engineers
                                           New Orleans District
                                          New Orleans, Louisiana




            ABSTRACT

                  Apparent sea level rise along the Gulf of Mexico coast varies from about 3
            to 35 millimeters per year. In developing civil works projects, this factor must
            be accommodated. Much of the central coastal area consists of marshlands that
            are about 25 to 50 cm above see 1 evel . Smal I ri ses i n sea I evel therefore can,
            inundate large areas. Changes in sea level can also cause saltwater to intrude
            i nto bracki sh estuari es, ki 11 i ng the marsh grasses and converti ng marshl ands i nto
            open water.     These marshes are valuable for the production of fish and fur
            bearers, for recreation, and for their social attributes. Several projects and
            studies under way are aimed at reducing the rate of loss occurring at present-
            -estimated to be about 100 square kilometers per year.           Sea level rise is one
            of several variables being considered in developing plans to save this coastal
            area.



            INTRODUCTION

                  Sea level rise is one of the many factors that influence the planning and
            development of federal water resource projects in coastal areas of the United
            States.    It affects both sides of the scale used by planners attempting to
            balance development with environmental preservation.

                  Federal participation in a water resource development project results from
            congressional action based on impartial studies by the U.S. Army Corps of
            Engineers.     The process begins when a local government seeks congressional
            assistance in solving a specific water-related problem.               The U.S. Congress
            responds by asking the Corps of Engineers to determine the economic,
            environmental, and social feasibility of a project to solve the problem and the
            appropriate level of federal participation.

                  The U.S. Army Corps of Engineers is the largest engineering organization
            in the United States.       The U.S. Congress has given the Corps the mandate to

                                                        501










              North America

              provide engineering services in times of both war and of peace. The Civil Works
              elements of the Corps of Engineers are concerned with the development of water
              resource projects. Military officers fill the top leadership position in the
              Corps; the staff consists of primarily civilian professionals.        In the New
              Orleans District in @ouisiana, for example, 7 military officers and over 1,300
              civilians work with the Corps of Engineers. The Corps works closely with many
              other federal agencies, including the Environmental Protection Agency, the Fish
              and Wildlife Service,    the National Marine Fisheries Service, and the Soil
              Conservation Service.   It also works with many state and local agencies.      The
              costs of Corps projects are generally shared with a local or state government.

                   Corps regulations (Engineering Circular 1105-2-186) concerning future sea
              level rise require that a sensitivity analysis be done to determine if whether
              and how potential projects would be affected.    That determination is based on
              an extrapolation of historic local sea level rise as the minimum level and curve
              I I I (i . e. , 1. 5-meter ri se by 2700) of the Nati onal Research Counci 1 report (1987)
              as the high level (see Figure I in Titus paper on effects of sea level rise).
              Since it may be 25-35 years before we can determine which sea level rise scenerio
              is appropriate, projects sensitive to sea level rise should be designed to allow
              for future modification should it become necessary.


              EFFECTS OF SEA LEVEL CHANGE

                   The impact of changing sea level on the development of water resource
              projects depends on the project. We examine several examples.

              Navigation Channel.Projects

                   For channel projects, rising sea level would increase available depth,
              assuming no change in sedimentation which would have a small but positive effect
              on shipping. On the other hand, onshore facilities built at or near historice
              sea level could be damanged. In developing projects of this type, planners must
              provide for sea level rise in the design of onshore facilities and should
              recognize that future channel maintenance costs may be less than current ones.

              Navigation Locks

                   This paper defines navigation locks as structures designed to raise vessels
              from waterways that are tidal to water surfaces at higher (nontidal) elevations
              (see Figure 1). Because the height of the gates and walls of these structures
              is a function of the higher elevations, sea level rise should have little impact
              on their design.   Again, as sea level rises, the required lift will decrease,
              resulting in slightly lowered operating costs.

              Saltwater Guard Locks

                   These locks designed to prevent saltwater intrusion into freshwater basins
              that are at or near sea level. During high tides, the oceanside water levels
              exceed those on the inside (Figure 2). For this type of structure, any increase

                                                     502











                                                                                Schroeder



                   OCEAN SIDE                                           LAND SIDE


                                                                        ....... X7
                                                              11111 RRIII RM NORM: :I:r
                                                                                HUHIM,
                    .M.                           imp.:
                     M                                                    17, 717
                                                    @ 1i
                                                11  E M.
            MSL                                _M:
                                                                         P-7 . . . . . . .-1-7
                                Navigatiom Lock

         Figure 1. Diagram of navigation lock.




                    OCEAN SIDE                                          LAND SIDE
                     Y'Z  11111111111-PT.
                                      u.11 4, @t! 1
                                   zzi-UMI RM: M M1-Bg =M: t IMMM:-W :-mm
                                                          0   1
                                  MR! 1.          N MHU. ""1           2
                                                                 IN . . .... 11111IM: M. 1: ng
                                               :MI:-
                                      It 1;      "M MM @@qz
                                       1 1 N 1illkHM" '11h .1 M
                                   EMPI.M. i          5
                      -    MW's      ! .1 t:
                                                         ; ;:;
                    1! 1110- @10 1 "M2
             MSL        AM.


                         salt                  r Guard Lock


         Figure 2. Diagram of a saltwater guard lock.


         in sea level will require a like increase in the height of the walls and gates.
         This can be accomplished by either building the structure initially to
         accommodate future sea level rises or constructing the lock so that it can be
         added to in the future.

         Food Control Channels and Levees

             As sea level rises, the effective carrying capacity of a channel dike
         (leveed) decreases. The only way to make up for such a decrease is to add to
         the heights of the dikes. To accommodate future increases in sea level, it is
         usually prudent to acquire the necessary real estate when the original dike is
         built, and to do any necessary relocation of utilities to conform with future
         conditions. The dike itself can be raised in the future as conditions change.

         Hurricane Protection Dike

             This special type of levee is one of the public works structures most
         sensitive to changes in sea level.   Typically, a hurricane protection dike is
         built to encircle a major populated area. That area is often at or below sea

                                               503










               North America

               level.   These dikes are usually built to protect against the most severe
               meteorological events possible for the area (the Standard Project Flood). As
               shown in Figure 3, the populated area is, in effect, a bowl, and any overtopping
               of the dikes would cause water to pond and flood the city. It is imperative that
               these dikes be upgraded as sea level rises. As with other types of dikes, it
               is prudent to acquire sufficient rights-of-way and perform all utility
               relocations to conform to future changes.


               LAND LOSS IN LOUISIANA

                    Projects designed to protect barrier islands or coastal marshes are
               particularly vulnerable to changes in sea level. To illustrate the problem of
               developing this particular type of project to accommodate future sea level
               changes, an area along the central Gulf of Mexico will be used.

                    Located in the State of Louisiana, the coastal area consists mostly of low-
               lying marshlands less than I or 2 meters above sea level. As a result, small
               changes in sea level inundate large areas of the coastal marsh.           This area
               contains 407* of the coastal marshes of the United States and is suffering 80Y.
               of the national coastal marsh loss. These marshes were formed over geologic time
               as the Mississippi River migrated across the coastal area following natural
               geologic processes.     Today, those lands   are under attack from a number of
               sources. No single cause can be pointed to    as the culprit. Coastal and deltaic
               processes are too complex to permit easy      answers.   Each force - natural and
               human-induced   -  acts upon the other,        synergistically   intensifying    and
               accelerating each effect.




               HURRICANE TIDE


                                                              son


                              Hu.-                  anvem"', Levee

               Figure 3.   A hurricane protection dike used to surround a populated area and
               protect it from the most severe meteorological events.
               lmiig@

                                                       504











                                                                                   Schroeder

          Causes of Land Loss

               Nature is responsible for a share of the marsh loss. The long-term forces
          of sea level rise, subsidence, compaction, saltwater intrusion, and erosion have
          caused significant changes in the relative land and water surface elevations.

               Compaction and subsidence together are estimated to average 0.6 meters per
          century, but the rate ranges from about 4 meters at the mouth of the active delta
          of the Mississippi River to 1 meter at Grand Isle to less than 1/2 meter in the
          western portion of the state. Historical data indicated that sea level rise is
          an additional 0.15 meters per century.     Accordingly, changes in eustatic sea
          level forecast by many investigators (Boesch, 1983; Hoffman, 1983; Nummendal
          1983: Templet, 1985) are currently being exceeded by relative sea level rise
          along the Louisiana coast.

               Both sea level rise and subsidence accelerate saltwater intrusion and
          erosion, changing the marsh habitat.    Erosion eats away at Louisiana's 70,000
          kilometers of tidal shoreline and at the barrier islands. The erosion causes
          the shore and barrier beaches to retreat from 3 to 12 meters each year.

               The gradual erosive effect of daily natural forces on the barrier islands
          is dramatically accelerated by hurricanes and storm tides.       Big storms cause
          massive damage by cutting through islands and widening and deepening passes, such
          as that which occurred on one of the Chandeleur Islands that was widened during
          Hurricane Juan.

               Though natural forces play an important role in coastal land loss, the
          activities of people are also a major cause. Flood control is indispensable in
          the floodplain of the Mississippi River and its tributaries.           This flood
          protection and the economic development in Louisiana's coastal wetlands have
          caused much of the marsh loss.

               Flood control dikes on the rives have changed the annual hydrologic regime.
          In a natural hydrologic cycle, the swollen Mississippi and Atchafalaya Rivers
          would overflow their banks every spring, flooding the marshes with nutrient-and
          sediment-rich water. The sediments and nutrients would build and sustain the
          natural diversity of the marsh. Since dikes were built for flood control and
          protection of national and international navigation, the only water that flows
          into the marshes is rainfall.     Each year, 183 million tons of sediment are
          carried down the river. This material is not building new marsh as it did prior
          to the levee construction; rather, it is dropping off the edge of the Continental
          Shelf into the deep waters of the Gulf of Mexico.

               In this fragile coastal environment, activities in the interest of economic
          development interact with and intensify the natural processes.            Leveeing,
          channelization, oil exploration, and agricultural, urban, and industrial
          expansion have accelerated the rate of marsh loss. The marshes are laced with
          13,300 kilometers of navigation, drainage, and petroleum access canals that
          segment the marsh.


                                                 505











             North America

                  With no annual flood of fresh water to hold back intruding saltwater, the
             marshes and cypress swamps that are not tolerant to salt are being destroyed and
             replaced with open-water ponds. These open-water areas increase the interface
             between water and marsh, causing more erosion. Across the Louisiana coast, one
             hundred square kilometers of marshlands are lost each year.

             Effects of Land Loss

                  What will this loss of a half million hectares of Louisiana's coastal marsh
             mean to the economy of the nation, to the development of the state, and to the
             people who live, work, and play in the coastal marshes?

                  About $300 million in marsh real estate value will be lost by 2040.
             Moreover, as marshes are lost, the Gulf of Mexico's estuarine -dependent fishery
             will decline. By the year 2040, commercial and recreational fish and wildlife
             harvests will be down to about 70 percent of the present harvest. The impact
             on the nation's economy will be an annual loss of $114 million. Sport fishermen
             and hunters will lose 4 million activity-days of recreation by 2040 as compared
             with today.    The annual economic impact of this to the nation will be $19
             million.

                  Loss of the coastal marshes threatens most of the national, state, and
             local development investment in the coast. This includes about 250 kilometers
             in portions of major waterways built by federal and state governments. The banks
             of these waterways will be lost to erosion.          The cost of the increased
             maintenance dredging that will be required in these waterways could exceed $50
             million a year.

                  Hurricane protection dikes will have to be enlarged and shielded from
             erosion. About 90 kilometers of federal hurricane protection projects, including
             the "Lake Pontchartrain and Vicinity," the New Orleans to Venice," and the
             "Larose to Golden Meadow" projects, will have to be protected to maintain the
             current level of protection. The estimated coasts could exceed $38 million.

                  Roads, pipelines, and utilities will require relocation.         Nearly 160
             kilometers of federal and state highways, about 44 kilometers of railroad tracks,
             2,500 kilometers of oil and gas pipelines, and 620 kilometers of utilities and
             telephone lines will have to be relocated. These relocations would cost billions
             of dollars.

                  Property will be lost or will have to be protected at great expense. About
             1,800 business, residences, camps, schools, electric power substations, water
             control structures, pumping stations for gas, oil, and water, and storage tanks
             will have to be protected or relocated.

             Ongoing Projects

                  Land loss is a significant national problem, and the U.S. Army Corps of
             Engineers has several projects and studies that specifically address this
             problem. Protecting people along the Mississippi River from flooding requires

                                                    506











                                                                                   Schroeder

          a system of river dikes which confine the water that historically flooded the
          marshes adjacent to the river and prevent the annual nourishment of those marshes
          essential for their maintenance.

              The Corps of Engineers and the State of Louisiana plan to restore a portion
          of the marsh flooding cycle in a way compatible with flood protection.       Three
          freshwater diversion projects are scheduled for implementation in the Louisiana
          coastal areas. Those projects will introduce fresh water from the Mississippi
          River into the adjacent marshes and estuaries.     Fresh water diverted through
          these structures will restore and enhance wetland vegetative growth by
          establishing desirable salinities. These salinities and much-needed nutrients
          carried by fresh water will increase the productivity of the marshes' fish and
          wildlife.

              Another tool to help offset coastal land loss is the use of dredged material
          to build new or restore sinking marshes. Over 1,200 hectares have been created
          through the Corps of Engineers' maintenance dredging program.        Creation of
          another 7,500 hectares through the future enlargement of the Mississippi River
          is planned.

              Diverting sediment to create new lands has also helped to mitigate some of
          the ongoing losses.    In addition to those already constructed, the Corps of
          Engineers is studying the cost-effectiveness of a system of uncontrolled sediment
          diversions within the active delta of the Mississippi River.

              The Corps of Engineers' regulatory program has been a major influence on
          human activity in the coastal zone. Each year the Corps' New Orleans District
          issues between 1,500 and 2,000 permits, and processes between 2,000 and 2,500
          permit applications. Permitted work is inspected to ensure that it conforms to
          Corps criteria, which include measures designed to prevent as much damage to
          marshes and other wetlands as possible. For example, the permit applicants are
          required in some cases to construct a wooden road over the marshes, rather than
          dredging an access canal.

          Louisiana Coastal Area Studies

              Several ongoing studies are attempting to develop long-term solutions to
          the coastal loss problems. The costs of these studies are being shared by the
          federal government and the State of Louisiana. In these studies, specific areas
          will be targeted for preservation or enhancement. Obviously, every acre of the
          coastal marshes cannot be saved, but many acres can.

              Many factors will be used to determine which area exhibit the highest
          likelihood of success. Topography will play a major role -- shallow water areas
          not subject to high wave energy would be a prime location. Other factors would
          include cost, proximity to populated areas, availability of a sediment supply,
          and environmental considerations.   The Corps/state study is using a variation
          on the usual federal benefit-to-cost evaluation methodology.      In this study,
          alternatives will be compared based on cost-effectiveness. A full array of both
          structural and nonstructural solutions will be analyzed.

                                                507










               North America

                    Sea level rise will complicate this already complex situation. Since many
               of the solutions being considered do not involve hard structures, but rather
               include such approaches as freshwater diversion, sediment diversion, dredge spoil
               placement, and regulatory control, it is likely that sea level rise can be
               accommodated.



               BIBLIOGRAPHY

               Boesch, D.F., Levin, D., Nummendal, D., and Bowles, K. 1983.           Subsidence in
               Coastal Louisiana:    Causes, Rates, and Effects on Wetlands.        Washington, DC:
               U.S. Fish and Wildlife Service, Division of Biological Services.

               Hoffman, J., D. Keyes, and J. Titus. 1983. Projecting Sea Level Rise to the
               Year 2100. Washington, DC: U.S. Environmental Protection Agency.

               Nummendal, D.   1983.   Future sea level rise along the Louisiana coast.         Shore
               and Beach, April.

               Templ et, P.   1985.   Land loss in' Louisiana:      A White Paper.     Zachary, LA:
               Templet Resources.

               U.S. A m@y, Corps of Engineers. 1988. Guidance on the Incorporation of Sea Level
               Rise Possibilities in Feasibility Studies. Engineering Circular 1105-2-186 Draft
               V 1.31, 20, Washington, DC: U.S. Corps of Engineers























                                                       508



                                                        *U.S. GOVERNMENT PRINTING OFFICE: 9 9 02 6 76 6 Y





























































































                                                                                                 I















                                         I

                                            3 6668 00000 5373