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

                                                                 K. 'It@ 90 - -,!;. .2


        Rockingham
        Planning                        121 Water Street, Exeter, N.H. 03833 (603)-778-0885
        Commission


  PI9



                                     Preliminary Study of
                           Coastal Submergence and Sea Level Rise
                             in Selected Areas of New Hampshire


                                        September 1991






















                                                            .j
                                                                REGIONAL
                                                                PLANNING
                                                        0
                                                        0          0 00



















                                                 Preliminary Study of
                                   Coastal Submergence and Sea Level Rise
                                      in Selected Areas of New Hampshire


                                                     September 1991


















                                                     Prepared by the
                                           Rockingham Planning Commission
                                                     121 Water Street
                                                    Exeter, NH 03833
          \J-'                                        (603) 778-0885






            This report was financed in part by funds provided by the New Hampshire Office of State Planning Coastal
            Program, through the Coastal Zone Management Act of 1972, as amended, administered by the Office of
            Coastal Resources Management, National Oceanic and Atmospheric Administration.
















                                      TABLE OF CONTENTS




               SECTION                                                           PAGE



         I.    Introduction   ..............................................      1


                    Purpose and Scope    ....................................     2
                    Study Area   ...........................................      3
         II. Methodology     ................................................     7
                    Data Sources   .......................... ; ...............   7
                    Interpolation    ........................................     7
                    USGS Depiction of Low Lying Areas      ....................  12

         III. Sea  Level Rise   ............................................     13


                    Causes   ...............................................     13
                    Current Projections    ...................................   15
                    Potential Land Use and Natural Resource Impacts      ....... 17

         IV. Identification of Potentially Threatened Areas        ............  19


                    Data Sources    .........................................    19
                    Preliminary Results    ...................................   20
                    Land Use Impacts    .....................................    23
                    Natural Resource Impacts -Wetlands        .................  31


         V.    conclusion   ................................................     32



               Bibliography














                                      LIST OF MAPS      FIGURES



          FIGURE/MAP        TITLE                                                        PAGE



          Figure 1          Sea Level Change For the Past 35,000 Years         .......    14

          Figure 2          Relationship of Vertical Datum and Sea Level          ....    19

          Table I           EPA Sea Level Rise Projections        ..................      16

          Map I             Study Area Locus     ................................           5

          Map 2             USGS Topo Maps, Study Area Sections         .............       6

          Maps 3A & 3B      Elevation Map, No. Hampton & Exeter        .............     9-10

          Map 4             Elevation Map, 2 Foot Contours-No. Hampton          ......    11

          Maps 5A & 5B      Submergence Risk Areas, No. Hampton & Exeter         ..... 21-22

          Maps 6A & 6B      Flood Hazards, No. Hampton & Exeter        .............   24-25

          Maps 7A & 7B      Existing Land Use, No. Hampton & Exeter         .........  26-27

          Maps 8A & 8B      Risk Areas & Land Use, No. Hampton & Exeter          ..... 28-29












          I.   INTRODUCTION


               Coastal shoreline erosion and recession are well known environmen-
               tal hazards in the Seacoast region of New Hampshire. The Blizzard
               of 1978 and more recent coastal storms serve as reminders of the
               hazards that natural storm events pose to low lying doastal areas.
               Coastal erosion and recession are caused by the combined effects
               of wave and wind erosion and by very gradual land submergence
               caused by geologic processes.' Within the past decade increasing
               concern has focused on the possibility that global climatic
               warming will cause a relatively rapid rise in sea level and result
               in greatly increased hazards from coastal erosion       and flooding.

               An increasing body of evidence suggests that the ef f ects of global
               warming expected to appear within the next 50 to 100 years will
               cause a significant rise in sea level. The EPA, for example, has
               projected global sea level rise to be in the range of 1.8 to 11.3
                                        2
               feet by the year 2100.      Measured sea level rise during the past
               decade indicates that the upper range of these projects are
               unlikely. However, even a small rise can have a major effect in
               low lying coastal areas. Since 1929, relative sea level has risen
               nearly 0.5 feet in some areas of New England. (Giese, Aubrey,
               1987)

               Although the effects of cl imatic- induced sea level rise may not be
               felt in New Hampshire for several decades, it is not too early to
               begin examining the scope of the. problem they may cause. Some of
               the most cost-effective solution@; to property losses that could
               arise take several decades to implement. Future dislocations of
               development can be greatly lessened -by directing development away
               from areas that lie within the range of likely sea level rise.

               Over the next decade and beyond it will be important to carefully
               assess and quantify the threat that.sea level rise will pose to
               New Hampshirel's coastal communities.        To do this accurately,
               detailed elevation data will eventually be needed in order to
               determine the precise land submergence patterns that should be
               anticipated.     To date the evidence supporting any specific



               'Passive Retreat of Massachusetts Coastal Upland Due to Relative
          Sea Level Rise, G.S. Giese, D.G. Aubrey, Mass. Coastal Zone Management,
          1987.

               2Projecting Future Sea Level Rise, J.S. Hoffman, D. Keyes, J.G.
          Titus, EPA 1983

                                                1









              estimate of sea level rise is not strong enough to justify the
              large expenditure of funds needed to develop such data.        Until
              this evidence exists it is appropriate to attempt to use existing
              elevation and map sources to identify the general     location and
              magnitude of coastal upland inundation.


              PurROse and Scope                         C   -    . -.-_

              The purpose of this study is to evaluate, within   a confined study
              area, the use of existing map sources to identify  areas potential-
              ly at risk from projected sea level rise. Secondary purposes of
              the study are to assess, in qualitative terms, the magnitude of
              potential damage to facilities and property that could result from
              passive sea level rise and to begin to identify some of the long
              term planning and public policy issues that arise from this
              problem.

              Specific objectives include:

                   to apply and evaluate methods for estimating coastal upland
                   submergence using existing USGS topographic maps;

                   to test methods for interpolating one or more contour
                   intervals between stated USGS contours based on site-specif ic
                   elevation maps, and, to use this information to depict the
                   extent of vulnerable areas under several sea level rise
                   scenarios;

                   to evaluate the applicability of the methods employed for use
                   in other areas of New Hampshire's coastal zone;

                   to assess the need to develop higher accuracy elevation data
                   for the NH Coastal Zone and identify other related research
                   needs.


              Due to a number of problems encountered in using available site-
              specific elevation maps, it was not possible to achieve a usable
              result for the second of these objectives. Specifically, it was
              not possible to develop verifiable interpolations of USGS contour
              intervals against which different sea level rise scenarios could
              be applied.    Nonetheless, it was possible to create a useful
              depiction of areas generally vulnerable to submergence using
              existing USGS contours (see Section IV).



                                             2









               Study Area

               Three relatively small areas were originally planned to be
               included in the study: one on the Atlantic coast and two along
               the Squamscott River. Two of the three areas are covered by the
               Exeter and Hampton USGS metric series (1:25,000) qdadrangle maps
               (quads).   These maps feature 3 meter (about 11 feet) contour
               intervals. The third area was to be loc&ted- within- the Newmarket
               standard series (1:24,000) quad which has 20 foot contour inter-
               vals, or half the vertical resolution of the metric series quads
               used.


               During the initial project investigation it became obvious that
               the Newmarket quad did not provide sufficient elevation resolution
               to depict areas at risk from coastal submergence. The third area
               was therefore dropped from the study and the others were expanded
               in size.


               The study areas selected (see Maps 1 and 2) cover the coastal
               section of North Hampton (including tidal rivers/estuaries) and
               the portion of the Squamscott River (including tidal tributaries)
               located in Exeter.     The North Hampton study area was selected
               because it contains all the features characteristic of the
               Atlantic coast in New Hampshire- rocky shore, sandy beach and
               tidal marsh/estuary.      It was also selected because detailed
               engineering plans were available (complete with two foot contour
               elevation data)@ which cover much of the immediate coastal area.
               These plans were developed by the Kimball Chase Co. in 1990 for
               the Rye Beach-to-Hampton Forced Main sewer project. They cover a
               several-hundred-foot wide corridor centered along Route IA.

               The study area in Exeter was selected because it is characteristic
               of the numerous tidal rivers in the New Hampshire coastal zone
               which may also be affected by sea level rise. The specific
               location was chosen because several GIS data layers useable in
               this study had already been developed in conjunction with a
               separate Coastal Program project (Inventory and Analysis of the
               Sauamscott River Corridor, Rockingham Planning Commission, June
               1991).

               cautiongry Note

               The USGS-based maps contained in this report are not designed to
               show site or parcel-specific information. The source map scale
               (1:25,000) makes them inappropriate for such use.        They are not
               intended for use in identifying individual properties that may be

                                               3










              at risk in the future but rather to show general areas that would
              be affected under the stated sea level rise scenario. Within the
              general areas identified, it is likely that smaller tracts of
              higher (and saf er) elevation exist which do not appear separately
              due to the lack of elevation detail.


              Further, the reader should recognize that the submergence risk
              areas shown are hypothetical in the senae that they-are based on
              the assumption that a significant rise in sea level will occur.










































                                            4




































                                                                                                                              41


                                                                               GREE       D
                                                                                                                                                                             MAP 1
                                                        @THATHAM
                                                                                                           RYE
                              EXE R                                                                                                                 Coastal Subme
                                                                                                                                                             Study Area
                                                                                           TON






                                                                                                                                                    Study Areas                  Primary


               E                     KENSIN                                                                                                         Ocean                        Secondar
                                                             UPTON F                                                                                                     FNI

                                                                                                                                                    Rivers                      Town Bo


                                                                                                                                                    Lakes  & Ponds



                                                                                                                                                    Reservoirs





                                                                                                                                             Source: USGS 1:100,000 DLG Data digitized
                                                                                                                                             by Complex Systems.

                                                                                                                                             Map prepared by the Rockingham Planni
                                                                                                                                             October 1991.





                                                                                           MAP 2
                                                             North Hampton Study Area - USGS Map

                                                                                                                            0
                                                                                                                                                             .4
                                                                                                  N                     C   rse


                                                                                                                                         Francis
                                                                                                                                        liege
                                                                                                                                             Jenni     de

                                                             -7                                                             rse
                                    0



                                                                                                                                                                                    _0
                                                                                                                                                                                   e


                                                                                                                          ric





                                                                                         CHAF@
                                                                                                                    \@ O@e                     Fox Hill,
                                                                                                                                               Point                    13             15

                         ot
                                                                                                                                                     2
                               0

                                                                                                                                                                                   13


                                                                                                                                   Boars Head




                                                                                                                                                       7



                       Exeter/Squamscott River Study Area - USGS Map


                                                                  e        I     a I
                                                                                d
                                                                                                                                                                  N

                              0
                                                                                                                              &



                                                                                      in

                                                                                           f            1         1-3
                                                                                       tir e

                                                                                                                          00
                                                                                                       D
                                                                Ind rial,                                                                       SCALE: 1"                25,000"

                                                                   VVU
                                                                   in




                                                                                                              S
                                                                                                                                                             SOURCE.
                                                       S
                                                                                                                                               Exeter New Hampshire/Mass.
                                                                                                                                         1:25,000-scale metric topographic map
                                                                                                          W                                                USGS, 1985


                                                                                                             6












              METHODOLOGY


              Data Sources


              As proposed, the focus of this study was to use exist    ing, readily
              available data sources to identify the lowest of low"lying coastal
              areas. Three primary mapped sources were used:

                    Exeter, New Hampshire, USGS metric series quadrangle map at
                    1:25,000 scale, 7 1/2 x 15 minute coverage, 3 meter contour
                    interval, published in 1985.

                    Preliminary Engq@neering Plans (Draft), 1990, Forced Main
                    Sewer Project - Rye. NH - Hampton, NH; prepared by Kimball
                    Chase Co., Portsmouth, NH.

                    Flood Insurance Rate Map, North Hampton, NH (1986) and
                    Exeter, NH (1982 ) FEMA, Scale: 1:4800.

              The  first two sources were used to identify elevation, the FIRM
              maps were used only to compare the low elevation areas as
              identif ied f rom the USGS map to the Federally def ined f lood hazard
              areas (100 and 500 year frequency floods).

              Absent from the list of mapped sources is the USGS Digital
              Elevation Model (DEM) "map" f or the study area.          As of this
              writing, DEMs which cover the New Hampshire Coastal Zone are not
              yet available, except for the Haifipton quad.

              Important non-map data sources included a number of articles and
              papers from which sea level rise estimates were obtained. These
              sources are listed in the Bibliography included at the end of this
              report.


              interpolation

              The object of interpolating between existing contour lines on the
              USGS map is to. artificially create a higher resolution of
              elevation data--i.e., to improve upon the elevation detail
              contained on available USGS maps. A simple linear interpolation
              between existing contours (drawing a new contour line halfway
              distant between two existing contours) would, by itself, be
              invalid and unusable for the purpose intended. The concept tested
              here was to use elevations shown on a site-level engineering plan
              as a guide with which to produce interpolated contours on the USGS

                                              7












               map

               To assist in both the interpolation and comparison, the USGS
               contour intervals (three meter resolution) were digitized from
               mylar quads (see Maps 3A & 3B) and plotted at a greatly expanded
               scale.   Similarly, two-foot intervals were digitized from the
               sewer project engineering site plans (see Map 4). . On the USGS
               plot a manual, linear interpolatioil betweeh--the indicated
               shoreline and the three meter contour was drawn (i.e. a 111.5 meter
               contour").

               Unfortunately, it was not possible to rectify, within acceptable
               limits, the engineering plans to the USGS maps.-., Therefore, no
               GIS-based comparison between the contours could be made and no
               usable interpolation could be produced.

               We were unsuccessful in applying the proposed method for two
               reasons. First and most important, the maps were not spatially
               compatible.    After both USGS and Site Plan study areas were
               digitized, attempts were made to combine the coverages using the
               RPCfs GIS system. This proved to be impossible because the site
               plan was not referenced to the State Plane Coordinate System, or
               any other spatial reference system (UTM, Lat-Long, etc.). Efforts
               to "force" the site plan into - a common reference system were
               unsuccessful due to apparent distortions in the site plans
               relative to the USGS maps. It is evident that the site plan maps
               were not prepared from an orthophoto base. Failing this, the USGS
               and site plan coverages were plotted at a common scale (approxi-
               mately 1:2400) and physically overlaid.        This allowed limited
               manual comparisons for small segments of the study, one area at a
               time (by manual "rubber sheeting   11).

               Comparing these limited areas revealed the second reason why
               elevation contours could not be interpolated. The large differ-
               ence in scale and detail of the source maps (one order of
               magnitude) resulted in elevation data that was too dissimilar to
               be used as intended.     The detailed contour shapes shown on the
               site plan were, in most cases, absent from the low resolution
               contours on the USGS map. In other words, the detailed land forms
               which show up on the site map are lost on the smaller scale USGS
               maps. This makes the transfer of information from one map scale
               to another impossible to do by any consistent and reproducible
               method.    This somewhat unexpected result was explained in the
               written report of a moreextensive submergence study prepared for



                                               8















                                                                               N







                                                                                                                                 Bass Beach                               MA
                                                                                                             Philbrj@ ck Pond               Coastal             Subm
                                                                                                                                               North Hampt
                                                                                                                                                    Contours/

                                                      A IOID
                                                                                                              -----------



                                                                                                                                            Mean High Water- VV       Primar
                                                                                                                                            3 Metres


                                                                                                                                            3-6 Metres                Seconds



                                                                                                                                            6-9 Metres                Road o

                                                              Little RjW S,,,V
                                                                                                           Little Boar's Head               9-12 Metres               Stream


                                                                                                                                            12-15 Metres              latermi



                                                                                                                                                                      Town B


                                                                                                                                     Sour a: USGS 7.5' and 15' Quadrangles,
                                                                                                                                     bY Ccomplex Systems and   RPC.

                                                                                                                                     Map prepared by the Rockingham Plaon
                                                                                                                                     October 1991.
                                                         9

























                                                                                                                                                                         MAP

                                                                                                                                              Coastal Subme
                                                                                                                                                            Exeter S
                                                                                                                                                       Contours/E



                                                                                                                                              Mean High Water-           Primary
                                                                                                                                              3 Metres            N

                                                                                                                                              3-6 Metres                 Secondary


                                                                                                                                              6-9 Metres                 Road or S


                                                                                                                                              9-12 Metres                Streams a


                                                                                                                                              12-15 Hetres               Intermitt


                                                                                                                                                                         Town Bou
                                                                                                                                       S;UTce: USGS 7.5' and 15'  Quadrangles, dig
                                                                                                                                       b C 0 mplex Systems- and  RPC.

                                                                                                                                       I(ap prepared by the Rockingham Plannin
                                                                                                                                       October 1991.

                                                         10

























                                                                                                                        MAP 4

                                                                                                                    Coastal Submergence Pr
                                                                                                                       North Hampton Study
                                                                                                                             Engineering Plan --
                                                                                                                          Contour/Elevation Ma

                        --4

                                                                                                                                              0-4 feet                   12-14 F


                                                                                                                                              4-6 Feet                   14 -16 F



                                                                                                                                              6-8 Feet                   16-18 F

                          Q0
                          @7-@                                                                                                          E     B-10 feet                  18-20 F
                        QC4
                                                                                                                                              10-12 Feet                 20-22 F





                                                                                                                                        Source: Kimball Chase Engineering Plans
                                                                                                                                        by the RPC.

                                                                                                                                        Map prepared by the Rockingham Plann
                                                                                                                                        October 1991,









              the Massachusetts Coastal Zone Program (Giese and Aubrey/Woods
              Hole 1987). As explained in that report, the complexity of land
              forms   does not simplify as smaller and smaller segments are
              analyzed. Although the size of the area covered changes with the
              scale of he map, the complexity of the land forms shown remains
              more or less constant.      This means that the contour shapes
              representing land forms at a small scale are not necessarily
              consistent with those at a large scale -- therefore-,'large scale
              contours cannot be used to "fill-in" contours at a small scale.


              Despite the problems associated with creating a corrected
              interpolated contour, a qualitative assessment of the linearly
              interpolated 111.5 meter" contour was made. A manual comparison of
              the USGS- interpolated and site plan-derived contours suggests some
              general conclusions about the interpolated contour. In relatively
              straight shoreline sections and in areas where vertical relief is
              pronounced (such as Little Boars Head and other rocky shore
              sections) the interpolated contours appear reasonably accurate.
              In areas with low and irregular relief such as the tidal marshes
              and surrounding uplands, the interpolations appeared -much less
              accurate. It is in these flatter areas, unfortunately, that the
              greatest accuracy is needed.

              USGS Depiction of Low Lying Areas

              Despite the failure in generating interpolated contours on the
              USGS map, a reasonable depiction of sections vulnerable to sea
              level rise is possible using USG8 maps alone.

              During the course of this study, research was conducted into the
              relationship between USGS-depicted contours, the shoreline
              elevation, and tide elevations.: Based on the results of this
              research, it appears that the three meter contour interval can
              serve as a reasonable demarcation of the upland extent of risk
              from coastal submergence. This finding is significant in that it
              suggests that a readily available data source already exists which
              can be used to map, for general planning purposes, the areas that
              are potentially at risk.

              As is more fully explained in Section IV of this report, the three
              meter contour is equivalent to an elevation of approximately 5.3
              feet above mean high tide.     This elevation is within the upper
              range of sea level rise projected to occur within the next 50 to
              100 years.




                                            12











         III. SEA LEVEL RISE


              Causes


              As brief ly described in the Introduction Section, the apparent
              rise in sea level has two components: the very gradual sinking or
              subsidence of the land surface (Ilisostatic" change) occurring
              along the New England coast and the actual- rise in'average sea
              level (Ileustatic change").    The land surface and sea level
              elevations change independently of one another -- hence the terms
              "relative" and "absolute" sea level rise.

              Land subsidence is the result of vertical movement- in the earth's
              crust caused by geologic processes.       Isostatid changes vary
              greatly throughout coastal areas of the U.S.       Some areas are
              undergoing subsidence while others experience uplifting. In the
              New England coastal area the land is sinking (as documented in
              local tide-gauge data in Massachusetts) at a rate estimated to be
              1.9 mm/year.3

              Absolute sea level rise is caused by a long term, natural climatic
              warming which began at the end of the Pleistocene era (Ice-Age),
              approximately 15,000 years ago. Most geologists agree that the
              ocean level reached a low of about 130 meters below its present
              position at about that time, and rose rapidly toward its current
              level by about 5,000 years ago...,

              Since then it has risen very sl6wly (see Figure 1)       In recent
              studies of sea level rise in Massachusetts, the absolute sea level
              rise was estimated to be.1 mm/year (Aubrey and Emery, 1983).

              Changes in absolute sea level cause a change in ocean elevations
              with respect to a-reference point on land. Since the land may be
              sinking or emerging as well, change in the relative sea level is
              what must be considered in evaluating potential risks to the
              environment. Isostatic and eustatic changes are combined to yield
              the current rate of relative sea level rise -- approximately 2.9
              mm per year. Two-thirds of the change is due to subsidence and
              one-third to ocean level change. Since 1929, the reference year
              of the National Geodetic Vertical Datum (NGVD), mean sea level in
              our area has risen by 0.17 meters or 0.5 feet. Projecting this
              rate into the future, relative sea level rise in New England can


              3Eigenanalysis of Recent United States Sea Levels, D. Aubrey and
         K. Emery Continental Shelf Research, Vol. 2, No. 1, 1983.

                                           13









                 be expected to rise 0.75 feet above the existing levels over the
                 next 100 years, excluding any rise caused by the af f ects of global
                 warming.


                                                  Figure 1
                               Sea Level Change Over the Past 35,000 Years


                                               THOUSANDS OF YEARS AGO
                       0        5       10       Is      20       2S       30      35
                          -r-7- -T                                                  I






                    W
                    W 50-
                                    5\ 'S           /0     0/
                           s shells           _0%.0
                                              910
                           0cotites       A
                    WX     Acoraltine otgae % T                       Schott and Stuiver;
                    1-100 -psall-morsh peat A                           Redfield (14)
                    W      abeachrock      X.         I               Emery and Garrison (15)
                                                                      This paper (Table 1)


                      1501

                           Sea level curve for the past 35,000 years, showing a low stand about 15,000 years
                    .B.P., with a rapid rise until about 5000 years B.P. and a more gradual rise since then.
                    (From Milliman and Emery 1968)

                      SOURCE. Barrier Island Ecolog Godfrey and Godfrey,
                        National Park Service Monograph No. 9, 19 76.


                 A growing body of-scientific evidence suggests that an accumula-
                 tion of "greenhouse gases" (Mostly C02) in the atmosphere will
                 result in relatively rapid global: warming. Meteorological records
                 'indicate that global mean temperatures        were warmer in the 1980's
                 than at any previous decade for which           data exists.     one of the
                 many effects of this change will be a           relatively rapid rise in
                 absolute sea level.          Therefore, in     addition to the natural
                 relative sea level rise occurring in            New England, a f ar more
                 significant rise could occur causing an accelerated landward
                 migration of the existing shoreline.

                 It should be noted that the scientific community is not unanimous
                 in the opinion that an era of accelerated global warming has
                 begun. over the past several years a number of studies have been
                 published which refute the hypothesis. Not in dispute, however,
                 is the fact that the proportion of greenhouse gases in the
                 atmosphere has grown significantly since the mid 1800's. it is
                                         't
                                              "@o




























                                                    14









              inevitable that greenhouse gases will continue to accumulate so
              long as fossil fuels provide the greatest share of energy supply
              f or the developed world.   Although trends showing increases in
              average temperatures have been observed, some scientists maintain
              that it is too early to say with certainty that these increases
              are part of . a warming trend induced by the greenhouse ef f ect.
              Most believe that by the end of the century enough time will have
              elapsed to reveal with relative certainty whether sigfiificant and
              permanent global warming is occurring.     Even then, uncertainty
              will remain as to the magnitude of the warming and how it will
              translate into sea level rise.


              The consensus   of the scientific community is that, based on
              observed trends in C02 accumulation, global warming will result in
              an increase in average atmosphere temperatures of 30 to 50C in the
              next century -- as much warming as has occurred since the last Ice
              Age. Regardless of how successful mankind is in curbing future
              emissions of greenhouse gases, most climatologists have concluded
              that it is too late to prevent a 10 to 20C warming."

              Atmospheric warming will translate into rising sea levels through
              several mechanisms including ocean water expansion, the melting of
              mountain glaciers and the eventual disintegration of polar ice
              sheets. In addition to causing sea levels to rise, global warming
              is also expected to modify climate patterns.        Of particular
              importance to coastal area is .,the prediction that large ocean
              storms will tend to increase in.frequency and intensity, thereby
              increasing the vulnerability of 'low-lying areas to storm-driven
              erosion and flooding.



              current Proiections


              Projecting future sea level rise is very uncertain business. In
              developing the analytical tools with which to forecast sea level,
              many assumptions and variables must be considered including:
              world population, economic growth, C02 emissions, C02 absorption in
              the oceans, heat dispersion in the ocean and atmosphere, effect of
              cloud cover, melting of polar ice, etc.






              4Strategies for Adapting to the Greenhouse Effect, James G. Titus,
        APA Journal, Summer 1990.

                                            15









               One of the earliest comprehensive attempts to project sea level
               rise was made by the EPA in 19835 That effort took into account
               many of the factors listed above and resulted in the following low
               and high ranges of sea level rise:


                                           TABLE 1


                            ABSOLUTE SEA LEVEL RISE PROJECTIONS
                                (Hoffman, et al. (EPA) 1983)


                    Year                  Low Estimate                High Estimate
                                             (in feet)                  (in feet)
                    2000                        0.16                       0.56
                    2025                        0.42                       1.80
                    2050                        0.79                       3.84
                    2075                        1.25                       6.96
                    2100                        1.84                       11.32



               Now, eight years later, it can be said that the high estimate
               projections for the year 2000 appear to be over-stated. Based on
               observed rates of sea level rise (1 to 2 mm/yr), it would appear
               that less than 25% of the high estimate will be reached by the
               year 20006.

               More recent predictions have tended to exclude or diminish the
               disintegration of polar ice sheets as a major factor in sea level
               rise.    This has had the effe@t of reducing sea level rise
               estimates significantly. Recent studies suggest that a one foot
               rise by 2050 is more likely than EPAIs original "high" estimate of
               3.8 feet. This estimate would be more consistent with a 3 to 6
               foot rise by 2100 -- as opposed to the EPA "high" estimate of 11.3
               feet.   The area mapped as "submergence risk" for this study is
               def ined by a 5. 3 foot rise in sea level -"- an elevation within the
               range of current estimates for 100 years hence.

               These estimates represent absolute sea level change only. The
               local rate of subsidence must be added in order to obtain the
               relative sea level rise estimate. As discussed in Section III,



               5Projectinct Future Sea Level Rise, Methodology, Estimates to the
         Year  2100, Hoffman, Keyes, and Titus, U.S. EPA 1983.

               6Contemporary Climate Change and its Related Effects on Global
         Shorelines, F. Gable, Woods Hole Oceanographic Institute, 1989.

                                              16









               over the past 60 years, the Massachusetts coast has been sinking
               at 1.9 mm/year. If the subsidence rate for New Hampshire is the
               same as that of Massachusetts, then an additional 0.2luL.    " or 0.69
               feet in local sea level rise can be expected by 2100    and ",ould be
               added to the absolute sea level rise estimates for that year.

               Potential Land Use and Natgral Resource Impacts

               It is estimated that, nationwide, a one meter (3.28     foot) rise   in
               sea level will cause the submergence of about 7,000 square miles
               of dry land in the U. S. (an area roughly the size of Massachu-
               setts), (Titus, 1990).      Shorelines in many locations would be
               severely impacted, retreating hundreds of feet landward. A recent
               study of the impacts of sea level rise on wetlands showed that a
               rise of 2 to 7 feet could result in the loss of 50% to 90% the
               tidal marshes in the U. S. (assuming no inland migration of the
               marshes).

               An earlier N.H. Coastal Program study on sea level rise described
               extensively the kinds of impacts that can be expected along a
                                                  7
               coastal area like New Hampshire's      Several types of impacts were
               identified in that report which are briefly summarized here:
               Inundation, Adjustment of Baselevel, Erosion, and Current
               velocities.


                    Inundation of Land

                    Rising sea level will cause iand that is currently above the
                    high tide line to be submerged at high tide.          As the sea
                    level rises, coastal wetlands will migrate landward if there
                    are no obstructions (i.e. road berms, bulkheads, etc.) to
                    this movement.      Low marsh areas will be destroyed and
                    replaced with open water or mud flats.           Some f reshwater
                    marshes may become brackish or salt water marsh (assuming no
                    tidal flushing restrictions).        Very low lying roads and
                    developed land may be submerged at highest tides.           Actual
                    impacts from inundation will be determined by the'extent of
                    sea level rise, the topography of the upland and the extent
                    to which the current shorefront is displaced.





               7Rise in Sea Level and Coastal Zone Planning, Shevenell Gallen and
         Assoc./N.H. Office of State Planning, 1987.

                                              17










                     Adjustment of Baselevel

                     A rise in sea level will change surf ace and groundwater
                     flows.   For example, the slope of tidal stream beds will
                     change and tend to increase in the deposition -6f sediment -in
                     stream channels. Storm drainage in very low lying areas will
                     fail as high tide levels exceed'drain elevations.            The
                     freshwater/saltwater interface in the groundwater will
                     migrate landward, possibly contaminating near shore wells
                     with salt or brackish water.


                     Erosion


                     The impact of sea level rise on the shorefront will be
                     determined from topography.     In low lying coastal beaches,
                     the whole beach profile will tend to migrate landward if not
                     obstructed by attempts to save the existing shoreline and
                     avoid property losses.     This migration will be caused by
                     severe wave erosion of the existing beach, especially during
                     storm events. In areas of rocky and steeply sloping shore-
                     lines, minimal changes will occur. Average water depths in
                     intertidal zones will increase, allowing longer wind driven
                     waves to form and cause more erosion of bottom sediments.


                     Current Velocities

                     Tidal currents in constric'ted tidal rivers, streams and
                     culverts will increase in velocity as a result of higher
                     tides and the larger volume of water which flow in and out
                     with each tide cycle. Culverts that are not now constricted
                     may become so, and the flushing of wetlands will be altered.

               In summary, a wide variety of impacts to the coastal environment
               can be expected from rising sea levels as the various natural
               systems attempt to maintain a dynamic equilibrium with the
               changing conditions.

               Impacts from passive (meaning not caused by wave erosion) land
               submergence are the simplest to predict and evaluate and they are
               the only ones considered in the remaining sections of this report.






                                              18











                    IV.           IDENTIFICATION OF POTENTIALLY THREATENED AREAS


                                  Data Sources


                                  As explained in Section II - Methodology, the three meter contour
                                  line which appears on the USGS metric series quad ma"ps (1:25,000)
                                  is approximately 5.3 feet above the mean high tide line. The mean
                                  high tide line is represented by the shorrelifie on these maps. The
                                  shoreline contour is not, as is commonly assumed, the "zero"
                                  elevation.                  Rather it is equivalent to "mean high tide".                                                                         The
                                  relationship between the various vertical datum references shown
                                  in Figure 2.

                                  Although the                 average vertical distance between the shoreline and
                                  the three meter contour is 5.3 feet, the USGS cautions that this
                                  relationship may vary from place to place. The USGS contours use
                                  1929 NGVD (mean tide in 1929) as their zero vertical datum,
                                  however, the shoreline shown on the map is from a different source
                                       the NOAA Nautical charts. The shoreline is noted on the USGS
                                  maps as indicating the "approximate line of mean high water."


                                                                                                Figure 2
                                                              Differences in Vertical Datum and Sea Level
                                                                      (based on New Hampshire tide ranges)


                               3-Meter Contour - USGS Map
                                                                10         . ......... .. - ---- ------------- - - - ------------------------ --- ------------------------------------------- - - ---------------- -- -13.61 ft.
                                                            Highest                                                                                                   13.00 ft.
                                                            Recorded Tide


                                           5.3 Ft-
                                  (A vg. Verdcal
                            distance between
                                  shoreline and
                             3 meter contour)                -0. Mean High Tide                                                  .... . ................ .......I............. ............... 8.30 ft.
                                                                       (Shoreline on USGS Map)





                                                                                                Mean Tide                           ------ - --------- ------------------------------------ - 4.15 ft.
                                                                                                NGVD 1929                                   - --------------------------- ----------- 3.77 ft.






                                                                                                Mean Low Water (Tide)                                                 0.00 ft.




                                                                                                     19










              Because the shoreline is f rom a dif f erent source and uses mean low
              water as its datum rather than the NGVD of 1929, USGS cannot
              certify that the elevation accuracy is consistent with national
              mapping standards. For our purposes however, we have assumed that
              vertical distance is constant at 5.3 feet.


              Based on our understanding of the datum references, and of current
              sea level rise estimates, it appears that the three meter contour
              elevation adequately serves as a reasonable boundary of the upland
              extent of sea level submergence projected for the next century.
              This assumes that a sea level rise of slightly more than five feet
              will occur in this timeframe -- probably close to a "worst case
              scenario".



              Preliminary Results


              Maps 5A and 5B depict the land area in each study area which has
              an elevation of three meters (NGVD) or less. This area is labeled
              "Potential Submergence Risk Areas" and indicates those places
              which would be inundated when the mean high tide rises to a level
              approximately 5.3 feet higher than present levels. It indicates
              only areas influenced by passive submergence, not areas which may
              be affected by erosion and storm-damage.

              Approximately 340 acres in the North Hampton study area would be
              affected. This represents approximately 20% of the defined study
              area and 3.9% of the total land @rea of North Hampton. The area
              described is nearly identical in shape and size to the tidal marsh
              soils shown on the SCSINCSS Soil Survey Map for that area of North
              Hampton. Virtually all of the Little River Swamp, as well as the
              marshes in the vicinity of Philbrick Pond, would become open water
              for more than half the tide cycle. Inland of the Woodland Road/
              Route 111 intersection, the Little River would become ponded at
              high tide. Also, it appears f rom the maps that Old Locke Road
              would be submerged at high tide in several locations adjacent to
              Philbrook Swamp.    However, field observations show that the road
              itself is elevated above the surrounding area and would probably
              not be flooded at mean high tide.

              In Exeter the area below three meters is much less extensive due
              to relatively conf ined f loodplain of the river. Approximately 81
              acres would be af f ected. This represents less than one percent of
              the Town"s total land area. As with the North Hampton study area,
              there is a strong correlation between tidal marsh soil types and
              the submergence area. The submergence area generally remains

                                             20










                                                                                                                                          'INES, %01'0\;@



                                                                                                                                               Bass Reach                                   MAP


                                                                                                                                  Pond
                                                                                                             ow                                            Coastal Subme
                                                                                                                                                               North Hampt(
                                                                                                                                                                  Potential Su
                                                           R1. 10,p,                                                                                                              Risk           A


                                                                                                                                                           Potential Submer-             Primary
                                                                                                                                                           gence Risk Areas
                                                                                                                                                                                  FNI    Secondary
                                                                                                                                                                                  VA     Road or S
                                                                                                                      Link Boar's Head                                              2    Streams a
                                                                                                                                                                                  FN


                                                                                                                                                                                         lutermitt



                                                                                                                                                                                         Town Ron


                                                                                                                                                    Source: USGS 7.5' and 15'     Quadrangles, dig
                                                                                                                                                    by  Complex Systems and       RPC.

                                                                                                                                                    Map prepared by the Rockingham Plannin
                                                                                                                                                    October 1991.
                                                              121

























                                                                                                                                                                         MAP

                                                                                                                                          Coastal Subme
                                                                                                                                                        Exeter St
                                                                                                                                                   Potential S
                                                                                                                                                              Risk A



                                                                                                                                          Potential Submer-          Primary R
                                                                                                                                          gence Risk Areas

                                                                                                                                                                     Secondary


                                                                                                                                                                     Road or S



                                                                                                                                                                     Streams a


                                                                                                                                                              F/_\ 11 Intermitt

                                                                                                                                                                     Town Bou


                                                                                                                                    Source: USGS 7.5' and 15' Quadrangles, dig
                                                                                                                                    by Complex Systems and    RPC.
                                                                                                                                    Map prepared by the Rockingbam Plaunin
                                                                                                                                    October 1991.

                                                        22










              within 100-200 feet of the river except at the lower end of Swasey
              Park and along sections of Wheelright Creek, particularly at the
              Stratham/Exeter town line. The map indicates that Swasey Parkway
              is sufficiently above the three meter level to avoid flooding at
              mean high tide, however, field observations show the road to be
              nearly level with the ground on either side. Currently, extreme
              high tides have been observed to flood 15ortions of the Parkway.

              Maps 6A and 6B plot flood hazard areas defined in FEMA Flood
              Insurance Rate Maps (FIRMs). In North Hampton (1986 FIRM) a very
              close correlation can be observed between the potential submerged
              area and the 100-year frequency flood hazard area.-. In the Exeter
              study area the correlation is not as close; the 100 year flood
              correlates more closely with the area below the six meter
              elevation area than to the three meter area. The flood stage of
              the Squamscott is affected not only by tide but by the inflow from
              the Exeter River.     The higher apparent flood stage may be
              explained by the contributing influence of the Exeter River --
              which ends just upstream of the study area.

              The 100 year flood stage for the tidal marshes in North Hampton is
              indicated on the FIRM Map as IIEL 911 meaning nine feet above 1929
              NGVD. This is equivalent to a height above mean low tide of 12.8
              feet, or 0.8 feet lower than the elevation encompassed by the
              three meter contour.    Given this small differencel it is not
              surprising that the land areas -they describe are so similar in
              size and shape.

              The FIRM maps which cover the Exeter study area (dated May 1982)
              indicate a 100 year flood stage elevation of IIEL 811.   The lower
              flood elevation is consistent with the fact the tidal range of the
              Squamscott is smaller than that of tidal marshes directly adjacent
              to the ocean.



              Land Use Igpacts

              The final maps in the report show generalized land uses in the two
              study areas (Maps 7A and 7B), and a combination of submergence
              risk areas with land uses (Maps 8A and 8B) .    The North Hampton
              study area shows 10 to 12 areas where existing development is
              located within the submergence areas. A further evaluation was
              made based on the Town's land use map and on the USGS map. Based




                                           23




























                                                                                                                                                                         MAP
                                                                                                                                    Bass Beach

                                                                                                                Philbrick Pond                 Coastal            Subme
                                                                                                                                                 North Hampt(
                                                                                                                                                         Flood Haz

                                                            Rr. 101D





                                                                                                                                               50
                                                                                                                                                   Year                  Primary
                                                                                                                                               F  d Zone
                                                                                                                                               100 Year           FNI    Secondary
                                                                                                                                               Flood Zone

                                                                                                                                                                         Road or S

                                                              Linle Ri@,r
                                                                                                                                                                         Streams a
                                                                  ME                                         Linle Boar's Head

                                                                                                                                                                  F/\I/  Intermitt

                                                                                                                                                                         Town Bou


                                                                                                                                       Source: USGS 7.5' and 15'  Quadrangles, dig
                                                                                                                                       CSRC. FEWA Flood Hazard maps digitized

                                                                                                                                       Map prepared b  y the Rockingham Plannin
                                                                                                                                       October 1991.
                                                         24



















                                                                                                           NI                                                                  MAP 6

                                                                                                                                                   Coastal Subme
                                                                                                                                                               Exeter Stt
                                                                                                                                                               Flood Haz





                                                                                                                                                   500 Year                    Primary R
                                                                                                                                                   Flood Zone


                                                                                                                                                   100 Year                    Secondary
                                                                                                                                                   Flo od Zone

                                                                                                                                                                               Road or S



                                                                                                                                                                               Streams a


                                                              W.,                                                                                                              Intermitte
                                                                                                 Ih                                                                            Town Bon

                                                                                                                                           Source: USGS 7.5' and 15'    Quadrangles, dig
                                                                                                                                           CSRC.   FEMA Flood Hazard maps digitized

                                                                                                                                           Map prepared by the Rockingham Planning
                                                                                                                                           October 1991.
                                                           25





















     A








                                                                                                                                          Bam Beach                                  MAP
                                                                                                                             101
                                                                                                                                                     Coastal Subme
                                                                                                                                                        North Hampto
                                                                                                                                                                      Developec

                                                             Rt. 101D




                                                                                                                                                     Developed Land               Primary R


                                                                                                                                                                                  Secondary
                                                                Little River Swamp                                                                                                Road or S
                                                                                                               Little Boar's Head                                          FNI    Streams a

                                                                                                                                                                           F/I    Intermitte

                                                                                                                                                                           F/ 11  Town Bon

                                                                                                                                              Source: USGS 7.5' and 15'    Quadrangles, dig
                                                                                                                                              CSRC. Land Use Map, North Hampton Vast

                                                                                                                                              gap prepared by the Rockingham Planning
                                                                                                                                              October 1991.
                                                            26





























                                                                                                         NI                                                              MAP

                                                                                                                                             Coastal Subme
                                            -Ile
                                                                                                                                                        Exeter Stt
                                                                                                                                                            Developec
                                                                 X



                                                                                                                                             Developed Land      VV     Primary R

                                                                                                                                                                        Secondary


                                                                                                                                                                        Road or S


                                                                                                                                                                 FNI    Streams a

                                                                                                                                                                        Intermitte



                                                                                                                                                                        Town Bou


                                                                                                                                      Source: USGS 7.5' and 15'  Quadrangles, dig
                                                                                                                                      CSRc.  Land Use Map, Squamscott River St

                                                                                                                                      Map prepared by the Rockingbam Planning
                                                                                                                                      October 1991.

                                                         27




















                                                                                                                                                         Bass Beach                                     MA

                                                                                                                                Philb rick Pond                           Coastal Sub
                                                                                                                                         'M                                   North Ham
                                                                                                                                                                                 Potential
                                                                 Fj. iOID                                                                                           Risk           Areas               wi


                                     ;9                                                                                                                             Potential Submer-              Primary
                                                                                                                                                                    gence Risk Areas

                                                                                                                                                                    Developed Land                 Seconder


                                                                          ----------                                                                                                               Road or



                                                                                                                                                                                                   Streams
                                                                                                                              Linle Boar's Read


                                                                                                                                                                                                   Intermit



                                                                                                                                                                                                   Town Bo


                                                                                                                                                             Source: USGS 7.5' and 15'     Quadrangles, di
                                                                                                                                                             by Complex Systems and       RPC. North Ham

                                                                                                                                                             Map prepared by the Rockingham Planni
                                                                                                                                                             October 1991.

                                                                   28


























                                                                                                                                                                            MAP

                                                                                                                                                Coastal Subm
                                                                                                                                                              Exeter
                                                                                                                                                        Potential
                                                                                                                                             Risk         Areas wit


                                                                                                                                      90     P:teatial Submer-          Primary
                                                                                                                                             g uce Risk Areas
                                                                                           t                                                 Developed Land             Secondary


                                                                                                                                                                        Road or



                                                                                                                                                                        Streams


                                                                                 4 Z
                                                                                                                                                                        Intermitt



                                                                                                                                                                        Town Bou


                                                                                                                                      Sour ca: USGS 7.5' and 15' Quadrangles, dig
                                                                                                                                      by Complex Systems and RPC. Squamscott

                                                                                                                                      Map prepared by the Rockingham Plannin
                                                                                                                                      October 1991.

                                                          29









               on this evaluation it appears that approximately 24 of 196
               structures (12%) within the study area are located at or below the
               submergence risk elevation.      In addition, it appears that Old
               Locke Rd., as well as segments of Route 1A near the Hampton line
               and segments of Rt. ill and Woodland Road near their intersection
               will be partially submerged during normal tidal cydles. (See Map
               8A)

               The Exeter study area shows less impact. Only four small areas of
               existing development appear located within a submergence risk
               area:    Water Street - only the waterfront itself (from the
               Waterfront Park to the dam, the parking area and access road
               appears vulnerable) ; building on the Swasey Park side of the Water
               St./Swasey Parkway intersection;      a portion of the residential
               area below Jady Hill Rd., and development immediately adjacent to
               Wheelright Creek on Portsmouth Ave. With the possible exception
               of Swasey Parkway, no public streets appear to be affected.

               overall, the direct land use impacts of passive submergence from
               a sea level rise of 5 feet appear relatively minor in both study
               areas. This conclusion is not unexpected given the fact that the
               submergence risk areas are nearly the same as the areas defined as
               tidal marshes and flood hazard areas.           For the most part,
               structures within the submergence areas are already at risk from
               storm driven flooding.


               It should be noted that some of the structures identified as
               located below the 3 meter contoui may, if fact, be slightly above
               it. The USGS maps do not have sufficient vertical resolution to
               pick-up minor elevation variations that often exist around homes
               and along roads in low lying areas.            Field investigations
               revealed, for example, that the structures along Old Locke Rd. and
               the Road itself are elevated several feet above the nearby tidal
               marsh.


               While the direct impacts from passive submergence may be low, a
               sea level rise of this magnitude will expose many developed areas
               to increased risks from flooding, erosion and salt water intru-
               sion. For example, higher sea levels will expand existing flood
               hazard areas; some structures that are now safely outside flood
               hazard areas may well be within them after a significant rise in
               sea level occurs. An assessment of these additional risks will
               require further study.





                                              30










              Natural Resource Imnact -- Wetlands,

              one of most serious environmental impacts that is expected to
              arise from sea level rise is the destruction of coastal wetlands.
              Recent EPA research on the subject concluded that wetlands losses
              in the range of 26% to 82% would accompany a sea level rise of-1
              meter' The role of coastal wetlands in providing fishery nursing
              grounds, habitat for migratory and nestirrg birds and biher crucial
              ecological functions is well understood. A significant loss of
              coastal wetlands is cause for great concern.

              The natural impact of a rising sea is to cause the entire wetland
              system to migrate landward (Titus, 1991). Under -.natural condi-
              tions, rising sea levels will cause the conversion of low marsh
              into open water or tidal flats, the conversion of high marsh to
              low marsh and the conversion of adjacent low lying uplands to high
              marsh.   This is the process that enables the wetland system to
              migrate landward. If sea level changes occur slowly enough, and
              if adjacent uplands are of gradual slope, then it is possible for
              the migration to occur with little net change in wetland acreage
              or productivity. After all, coastal wetlands have been migrating
              "inland" for thousands of years as the sea level has slowly risen.

              Unfortunately, there is good reason to believe that this kind of
              gradual migration will be disrupted in the future. one reason is
              that the projected rapid rate of. sea level rise may overwhelm the
              ability of the wetland ecosystem to keep pace. A second problem
              is that much of the upland immediately adjacent to tidal marshes
              is developed.      Landowners will surely resist the wetlands
              migration by erecting berms or bulkheads to stave off the advance.
              This will effectively halt wetland migration in such areas and
              contribute to the permanent loss of coastal wetlands. According
              to EPA estimates, eliminating migration obstructions (i.e
              preventing property protecting structures) can cut in half the
              total potential wetland loss due to sea level rise.

              If coastal wetland losses are to be minimized it will be crucial
              for federal, state and local policy makers to devise fair and
              equitable ways to abandon development that is in the path of
              wetland migration.





              "Greenhouse Effect and Coastal Wetland Policy... 11, J.G. Titus, US
                    EPA, Environmental Management Vol. 15 No. 1, 1991, Table 1

                                             31









              Such approaches might include:      acting now to limit future
              development in areas where wetlands are likely to migrate to;
              allowing development in sensitive areas only on the condition that
              no attempt will be made to protect the property (via bulkheads,
              seawalls, etc.) from advancing wetlands, and modifying the federal
              flood insurance program to greatly discourage--.     or disallow
              reconstruction of structures damaged as a consequence of sea level
              rise.




















































                                           32














                                                BIBLIOGRAPHY




           Cooke, R.U. and Doornkamp, J.C., Geomor-phology in Environmental Management, An
                 Introduction, Oxford University Press, Great Britain, 1977

           Federal Emergency Management Agency, Flood InsuranceStudy, Town-of-North Hampton,
                 New Hampshire, Rockingham County, Federal Emergency Management Agency, 1984

           Gable, Frank, Contemporary Climate Change and its Related Effects on Global
                 Shorelines, Coastal Research Center, Woods Hole Oceanographic Institution,
                 Woods Hole, MA

           Giese, G.S. and Aubrey, D.G. and Zeeb, P., Passive Retreat of Massachusetts Coastal
                 Upland Due to Relative Sea-Level Rise, Woods Hole Oceanographic Institution,
                 Woods Hole, MA, 1987

           Godfrey, Paul J..and Godfrey, Melinda M., Barrier Island Ecolocry of Cape Lookout
                 National Seashore and Vicinity, North Carolina, National Park Service
                 Scientific   Monograph Series Number Nine, U.S. Government Printing Office,
                 Washington, D.C., 1976

           Gornitz, Vivien and Kanciruk, Paul, ABsessment of Global Coastal Hazards from Sea
                 Level Rise, NASA GSFC. Institute for Space Studies and Columbia University, New
                 York, NY and Oak Ridge National Laboratory, Oak Ridge, TN, 1987

           ICF, Incorporated, Developing Policies to Improve the Effectiveness of Coastal Flood
                 Plain Management, ICF Incorporated, Fairfax, Virginia, July 1989

           Shevenell Gallen and Associates, Inc., Technical Report: Rise in Sea Level and Coastal
                 zone Planning, Shevenell Gallen and Associates, Inc., 314 South Main Street,
                 Concord, NH, October 1987


           Titus, James G., Greenhouse Effect and Coastal Wetland Policy: How Americans Could
                 Abandon an Area the Size of LlaBsachUBetts at Minimum Cost, Environmental
                 Management, Vol. 15, No. 1, Springer-Veriag New York Inc., 1991

           Titus, James G., Greenhouse Effect, Sea Level Rise, and Barrier Islands: Case Study
                 of Long Beach Island, New Jersey, Coastal Management, Vol. 18, United Kingdom

           Titus, James G., Strategies for Adapting to the Greenhouse Effect, APA Journal,
                 Summer 1990










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