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                                                           HISTORICAL TRENDS

                                  WATER QUALITY AND FISHERIES:
                                    ALBEMARLE-PAMLICO SOUNDS

                                                                 With Emphasis on the
                                                                Pamlico River Estuary

                                         .A Report to the
                                National Ocean Pollution Program
                                              and the
                               National Sea Grant College Program

                                       Donald W. Stanley
                                Institute for Coastal and Marine Resources
                                       East Carolina University
                                      Greenville, NC 27858-4353

                                          September 1992

                                 U.S. DEPARTMENT OF COMMERCE
                                   Barbara Hackman Franklin, Secretary
                             National Oceanic and Atmospheric Administration
                                      John A. Knauss, Under Secretary
                                      COASTAL OCEAN OFFICE
                                        Donald E. Scavia, Director
          Cn
          Cn                         National Ocean Pollution Program
              A"

                                       W. Lawrence Pugh, Director  LIBRARy
                                                                 NOAA/CCEH
                                                              1990 HOBSON AVE.
                                                             CFIAS. SC 29408
                                                                           -2623

                    H

                    This publication is sponsored by the National Ocean Pollution Program, National
                    Oceanic and Atmospheric Administration, U.S. Department of Commerce. The project
                    was administered under grant NA86AA-D-SGO46 as project R/SF-2 through the UNC
                    Sea Grant College Program, North Carolina State University, Raleigh, NC. Additional
                    support came from Texasgulf Chemicals, Inc., and from East Carolina University.

                    Additional copies ofthis publication are available from UNC Sea Grant, Box 8605, North
                    Carolina State University, Raleigh, NC 27695-8605. Order UNC-SG-92-04.

                    This document should be referenced as:
                    Stanley, Donald W. 1992. HistoricalTrends: Water Quality and Fisheries, Albemarle-
                    Pamlico Sounds, With Emphasis on the Pamlico River Estuary. University of North
                    Carolina Sea Grant College Program Publication UNC-SG-92-04. Institute for Coastal
                    and Marine Resources, East Carolina University, Greenville, NC. 215 pp.

                    Cover Illustration: Drawn by Steve Daniels, and reproduced from Doug Young (editor).
                    1980. North Carolina and the Sea, prepared by the North Carolina Marine Science
                    Council,N.C. Office ofMarineAffairs, N.C. Department ofAdministration, Raleigh, NC.

                       Contents

                       Preface / v
                       Chapter 1: Profile of the Al bema rle- Pamlico System
                              The Physical-Chemical Environment / I
                                     Geological Origin and Evolution / Climate / Freshwater Inflows / Tidal
                                     Exchange, Circulation, and Flushing / Salinity and Nutrients
                              Principal Uses / 8
                                     Settlement and Population Growth / Land Use / Commercial Fisheries
                                     / Recreation / Industry and Ports
                       Chapter 2: Major Environmental Concerns
                              Eutrophication -- As Evidenced by Blue-Green Algal Blooms / 15
                              Wetlands Loss / 16
                              Loss of Submerged Aquatic Vegetation / 18
                              Declines in Fisheries / 18
                              Fish Diseases and Kills / 19
                              Impairment of Nursery Area Function / 19
                              Shellfish Closures / 20
                              Toxicant Effects / 20
                       Chapter 3: Trends in Nutrient Production: An Estimate Based on
                                     Changing Land Use and Population
                              Methods / 24
                              Results / 29
                                     Land Use / Harvested Cr-opland Nutrient Mass Balance / Farm
                                     Animals Inventory and Nutrient Production / Point Source Nutrient
                                     Production / Trends in Nutrient Production by All Sources
                              Discussion / 46
                       Chapter 4: Pamlico River Estuary Water Quality Trends
                              History of Water Quality Studies in the A/P System / 53
                              Methods / 54
                                     DataSources / Changes inAnalyticalMethods / TrendAnalysis Techniques
                              Results and Discussion / 58
                                     Climatic Factors and River Flow / Water Temperature, Salinity, andpH

                    IV                                                                         Contents

                                  Nitrogen / Phosphorus / Nutrient Limitation in the Pamlico / Dissolved
                                  Oxygen / Chlorophyll a / Phytoplankton Species Composition and
                                  Biomass
                    Chapter 5: Stratification and Bottom Water Hypoxia in the Pamlico
                                  River Estuary
                           Introduction / 78
                           Methods / 79
                           Results and Discussion / 81
                                  Seasonal and Spatial Variability / Short-Ter7n Variability / Spear7nan
                                  Correlation Results / Interannual Trends / Event Frequency / Effects of
                                  Hypoxia on Pamlico Biota
                           Conclusions / 88
                    Chapter 6: The Pamlico River: Comparison with Other Estuaries
                           Introduction / 92
                           Nutrients / 92
                           Dissolved Oxygen / 95
                           Chlorophyll a and Phytoplankton Biomass / 97
                    Chapter 7: Trends in the Sounds' Fisheries
                           Commercial Fisheries / 103
                                  The Database / Edible Finfish   Blue Crabs    Shrimp    Oysters
                           Recreational Fisheries/ 115
                    References/ 117
                    Appendices / 133

                         Preface

                            Despite great interest in - and large       many stations in Galveston Bay and along
                         expenditures for -estuarine water quality      the Houston Ship Channel since the late
                         and fisheries management, there have not       1960s. Likewise, there is a twenty-rive
                         been evaluations of long-term trends in        year record of water quality from 20-30
                         conditions of most of our estuaries. Conse-    stations in the Pamlico River Estuary in
                         quently, little is known about the effective-  North Carolina. In the third estuary,
                         ness of past and present management            Narragansett Bay, no routine monitoring
                         programs.                                      program has been carried out, but enough
                            This is one of several products of a        independent studies have incorporated
                         study of long-term trends in water quality     water quality parameters to permit con-
                         and fishery resources in three important       struction of a comparable long-term data
                         U.S. estuaries: 1) Narragansett Bay, Rhode     set. In addition to water quality data
                         Island, 2) the Albemarle-Pamlico Sound         bases, there are catch statistics and records
                         system in North Carolina, and 3) Galveston     of management efforts for important fish-
                         Bay, Texas. The project had four specific      eries in each bay.
                         objectives:                                        These estuaries are characterized by a
                            1. To document long-term trends in          range of pollution problems, some of which
                         water quality and, where possible, identify    are unique to each, while others are shared
                         causes, consequences and significance.         by all. Narragansett Bay and Galveston
                            2. To assess whether problems are           Bayrepresent heavily industrialized, urban
                         similar or unique to each estuary.             estuaries with a long history of pollution.
                            3. To assess whether progress is being      They are subjected to intense port and
                         made in improving conditions in water          shipping activities, massive industrial dis-
                         quality and fishery resources and whether      charges and major domestic sewage load-
                         there are examples of success that would       ings from urbanized centers of population:
                         be useful for estuarine managers and           Houston in Galveston Bay; and Providence,
                         researchers elsewhere.                         Central Falls and East Providence in Nar-
                            4. To glean examples of the useful inte-    ragansett Bay. In contrast, the Albemarle-
                         gration of research and policy.                Pamlico Sound system is a relatively un-
                            The three estuaries chosen for this         developed estuary without major shipping
                         study have sufficient long-term data to        lanes, industrial activity ora denselyurban-
                         permit trend analyses and inter-estuarine      ized coastline. Instead, it is characterized
                         comparisons. In two of them, monitoring        by extensive wetlands along its shoreline
                         programs have been carried out for at least    with agriculture and forests as the major
                         two decades. The Texas Department of           land use types within its watershed. Yet it
                         Health and the Texas Water Commission          also is perceived as having a history of
                         and its predecessors, the Water Quality        water quality problems.
                         Board and the Department of Water Re-              This is one of three separate - but
                         sources, have been monitoring dissolved        comparable - reports that have been pre-
                         oxygen, nutrients, metals and bacteria at      pared on trends in pollutant loadings, water

                       V!                                                                                   Preface
                       quality and pertinent fisheries for each of     Pamlico River, has been sampled inten-
                       the estuaries. The other two are:               sively on a continuous basis over the past
                                                                       two decades. Two others, the lower Chowan
                       Stanley, Donald W. 1992. Historical Trends:     River and the Neuse River, have been
                          Water Quality and Fisheries, Galveston       sampled intensively during studies lasting
                          Bay. University of North Carolina Sea        2-to-5 years, and infrequently at other
                          Grant College Program Publication UNC-       times. The open waters ofAlbemarle Sound
                          SG-92-03. Institute for Coastal and Marine   were sampled intensively for a two-year
                          Resources, East Carolina University,         period in the early 1970s, but there has
                          Greenville, NC. 100 pp.                      never been an intensive water quality sam-
                       Desbonnet, A. and V. Lee. 1991. Historical      pling for the open waters of Pamlico Sound.
                          Trends: Water Quality and Fisheries,         Because the Pamlico River data set is, by
                          Narragansett Bay. The University ofRhode     far, the most comprehensive, I have decided
                          Island Coastal Resources Center              to restrict my analysis of trends in water
                          Contribution No. 100 and National Sea        quality to this sub-estuary.
                          Grant Publication #RIU-T-91-001.                 One ofthe most widely-held perceptions
                          Graduate School of Oceanography,             about the Pamlico River is that it has
                          Narragansett, RI. 101 pp.                    worse bottom-water dissolved "problems"
                          Three major topics are covered in this       now than in the past, and that this is
                       report: 1) nutrient production in the drain-    adversely impacting the estuary's fishery
                       age basin, 2) estuarine water quality, and      resources. Hence, Chapter 5 addresses the
                       3) fisheries. Preceding the first of these are  factors responsible for low dissolved oxygen
                       two introductory chapters. The first gives      episodes in the estuary. Chapter 6 sum-
                       some basic information about the physical       marizes some information about compari-
                       setting, hydrology, uses, and living re-        sons between the Pamlico River and other
                       sources oftheAlbemarle-Pamlic6 estuarine        estuaries, in terms of nutrient and phyto-
                       system. Chapter 2 briefly summarizes the        plankton concentrations.
                       major environmental issues for the estuary.         Historical records of commercial land-
                       In Chapter 3 1 attempt to develop an esti-      ings offinfish and shellfish are available on
                       mate of changes in potential point and          a county-by county basis for all of the
                       nonpoint source nutrient loading to the         Albemarle-Pamlico region. Unfortunately,
                       estuary over the past century. Actually,        however, the data reflect where the fish
                       this part of the study was not included in      were brought to shore, not where they
                       the original research plan. Rather, it          were caught, so that it is impossible to
                       evolved from a combination of my curiosity      equate landings in counties around the
                       about what nutrient loading rates to the        Pamlico River Estuary to catch in the
                       estuary might have been in the past, before     estuary. Thus, in Chapter 7 report, which
                       "cultural" eutrophication, and my frustra-      examines trends in fisheries, I was forced
                       tion resulting from the lack of adequate        into looking at the Albemarle-Pamlico re-
                       riverine nutrient concentration data upon       gion as a whole, rather than focusing on
                       which to base a direct estimate of historical   individual sub-estuaries.
                       loading trends.                                    Primary funding for this research was
                          Chapter 4 deals with historical trends       provided by the National Ocean Pollution
                       in water quality within the estuary. For a      Program Office of the National Oceanic
                       number ofreasons, water quality sampling        and Atmospheric Administration, U.S.
                       in the Albemarle-Pamlico region has been        Department of Commerce. The         *  project
                       very uneven. Only one sub-estuary, the          was administered as Grant R/SF-2 through
                                                                       the UNC Sea Grant College Program, North

                        Preface                                                                                    V11
                        Carolina State University, Raleigh, NC.         Community Development, Morehead City;
                        Additional support came from Texasgulf             Ms. KatyWest, Division ofMarine Fish-
                        Chemicals, Inc. and from East Carolina          eries, North Carolina Department of Natu-
                        University.                                     ral Resources and Community Develop-
                            Several persons in North Carolina and       ment, Morehead City;
                        Virginia state agencies provided courteous         Staff of the U.S. Government Docu-
                        and friendly assistance as I collected the      ments Section of the North Carolina State
                        information needed for the study. They          University Library, Raleigh;
                        include:                                           Staff of the Virginia State Library,
                            Mr. David Clawson, District Sanitarian,     Richmond; and
                        Shellfish Sanitation Program, Division of          Ms. Renee Hawkins of the Virginia
                        Marine Fisheries, North Carolina Depart-        State Water Control Board, Richmond.
                        ment ofNatural Resources and Community             Many hundreds of hours were spent
                        Development, Morehead City;                     transcribing data from the printed records
                            Mr. George Gilbert, Assistant Super-        into computer files. East Carolina Univer-
                        visor, Shellfish Sanitation Program, Divi-      sity students and staff involved in this task
                        sion of Marine Fisheries, North Carolina        included Ray Taft, Jeff Taft, Sharon Reid,
                        Department of Natural Resources and             Colleen Reid, Deborah Daniel, Anne
                        Community Development, Morehead City;           Anderson and Kay Evans. I thank M.
                            Mr. JeffFrench, Marine Biologist, Divi-     Brinson, J. Dorney, and K. Evans for re-
                        sion of Marine Fisheries, North Carolina        viewing an earlier draft. Mark Hollings-
                        Department of Natural Resources and             worth provided invaluable assistance in
                                                                        the preparation of the final draft.

                                                                        Greenville, North Carolina            D.W.S.
                                                                        December, 1991

                          CHAPTER

                          Profile of the
                          Albemarle-Pamlico Estuarine System

                              It is not the purpose of this chapter to             Say "coast" in North Carolina, and
                          provide a comprehensive analysis of the              everybody thinks beach, specifically the
                          ecology of the Albemarle-Pamlico Estuary.            broad, sandy aprons of the barrier islands.
                          Rather, it is a briefsketch intended to focus        Everything west of the beach is merely
                          the reader's attention on the system's               something through which to pass en route to
                          features which are most relevant to the              the water. And there is plenty of water.
                          water quality and fisheries data that will               It sometimes seems as if nature created
                          be presented below. Details of the ecology           the Coastal Plain so water would have
                          of the Pamlico River Estuary and Albe-               something to lap against and sky would have
                          marle Sound can be found in two Estuarine            something to rest upon. The Coastal Plain is
                          Profiles by Copeland et al. (1983; 1984).            a beautiful mosaic: sun-bleached tidal marsh
                          Giese et al. (1979) provide details of the           as broad as the eye can follow; level beach
                          hydrology ofeach ofthe major sub-estuaries           planing into the surf; mullet skipping on the
                          in the Albemarle-Pamlico Sound system.               water of the sound; boats of every size,
                                                                               shape and design; and magnificentflights of
                          The Physical-Chemical                                ducks and geese. Arrow-straight highways
                          Environment                                          where rows of crops flicker past the window
                              The Pamlico Sound covers an area of              like pickets on a fence. You can plow it,
                          about 5,335 kM2, making it the largest               graze it, till it, timber it, fish it, trap it, swim
                          sound formed behind the barrier beaches              it, and sail it. Bask in its warmth, boat it,
                          along the Atlantic Coast of the United               run it, drive it and follow it through
                          States. Giese et al. (1979) estimate that            centuries by reading its history in church
                          the total volume of water in the sound               graveyards.
                          averages about 26 billion m, or about 21                 It is, above all, a land in community with
                          million acre-feet. The average depth is              water and plow, where the good earth and
                          only about 4.9 m, and the maximum depth              bountiful sea provide all the rewards needed
                          is only 7.3 m (Figure 1.1 and Table 1.1).            to those who spill their sweat.
                              There are numerous tributaries and                                            G. Morris (1985)
                          embayments along the western shore of              River are one in the same. The Tar River
                          the Pamlico Sound. Two of these - the              is the major freshwater source for the
                          Tar-Pamlico River Estuary and the Neuse            estuary, but downstream from Washing-
                          River Estuary - are by far the largest.            ton, the name Pamlico River has tradi-
                          The Tar-Pamlico extends approximately              tionally been used. The combined surface
                          65 krn from near the town of Washington,           area of the Tar-Pamlico Estuary and its
                          NC to its confluence with Pamlico Sound.           sub-tributaries is about 582 kM2    . However,
                          Actually, the Tar River and the Pamlico

                                                                                                  Chapter I

                                   CHOWAN

                                                               ALBEMARLE SOUND

                    ROANOKE

                             R-PAMLICO

                                                                                      PAMLICO
                                                                                     SOUND

                                                                                                                    7

                                 NEUSE

                             Ch.                                                 ATLANTIC OCEAN

                                                                                    KM
                                                                        0    10   20   30   40                      7
                                                        Ce                      10      20      30
                                                                        0
                                                                                   MILES

                    Figure 1.1. Map of the Albemarle-Pamlico Estuarine System.

                                    Profile of the Albemarle-Pamllco Estuarine System                                                                                           3
                                    depths are shallow, averaging only about                                  than 5.5 m deep. Its volume is about
                                    3.4 m. The other important Pamlico Sound                                  5,310,000 acre feet (Giese et al. 1979).
                                    tributary embayment is the Neuse River
                                    Estuary. Beginning near the confluence of                                 Geological Origin and Evolution
                                    the Neuse River and the smaller Trent                                          The Albemarle-Pamlico system began
                                    River at New Bern, NC, the Neuse River                                    to form sometime after 17,000 years BP,
                                    Estuary extends 65 km to the mouth in the                                 when the last major glacial ice advance
                                    southwest corner of Pamlico Sound, only a                                 reached its maximum development. At
                                    short distance south of the mouth of the                                  that time sea level was as much as 130-160
                                    Tar-Pamlico River estuary. The Neuse                                      m lower than today. Consequently, the
                                    Estuary is similar in size and depth to the                               shoreline was far out on the continental
                                    Tar-Pamlico. The Neuse covers approxi-                                    shelf. Sand dunes were built up along the
                                    mately 394 kM2, and averages 3.6 m in                                     shore by winds blowing toward the land.
                                    depth.                                                                    As the ice melted and sea level rose again,
                                      The Albemarle Sound, extending about                                    between 17 thousand and 5 thousand years
                                    88 km from the mouths of the Roanoke and                                  ago, these dunes were separated from the
                                    Chowan Rivers eastward to the outer                                       shore in places, thus forming a string of
                                    banks, covers an area of about 2,419 kM2                              .   barrier islands. Breaching during storms
                                    It averages about 11 km wide, and has a                                   caused inlets to develop and lagoons to be
                                    maximum depth of nearly 9 m, but most of                                  flooded and eventually become wide, shal-
                                    the central area of the bay is little more                                low sounds. Further sea level rise, as well
                                                                                                              as continual wave action, caused the islands
                                                                                                              to migrate toward the land (Gade and
                                    Table 1.1. Hydrologic datafor Albemarle and                               Stillwell 1986). Today some of these barrier
                                    Pamlico Sounds (fi-om, Giese et al. 1979).                                islands (popularly known as the Outer
                                    A. Drainage area                                                          Banks) are moving landward each year at
                                        Albemarle Sound                17,879   mi"       46,309     kin'     up to 3 m, while sea level is risingabout 0.3
                                            Chowan River                4,943   mi"       12,802     kin      cm per year (Pilkey et al. 1978).
                                            Roanoke River               9,666   mil       25,035     km'
                                            Other                       3,288   mil        8,516     km'            The sounds are underlain with sedi-
                                        Pamlico Sound                  10,460   mil       27,092     kin      ments and sedimentary rock of marine
                                            Tar-Pamlico River           4,300   m?        11,137     km:
                                            Neuse River                 5,598   Mi2       14,499     km'      origin. These sediments were deposited
                                            Other                         562   mi"        1,456     km'
                                        Total                          28,357   mP        73,445     km,      over at least the past 100 million years
                                    B.  Surface area                                                          while the ocean covered portions of the
                                        Albemarle Sound &                                                     coastal plain (Brown et al. 1972). The
                                        tributaries                       934   Mi2        2,419     kin'     uppermost veneer of unconsolidated sedi-
                                        Pamlico.Sound &                                                                                                                           -s
                                        tributaries                     2,064   Mi2        5,335     km'      ments were laid down 25 to 1 million year
                                            Pamlico River estuary         225   mi'           582    kM2      ago in the Miocene and Pliocene epochs.
                                            Neuse River estuary           152   Mill          394    kM2
                                        Total                           2,998   m P        7,765     kmg      These are extremely varied and include
                                    C. Volurne                                                                gravels, sands, clays, peats, and all possible
                                        Albemarle Sound            5,310,000    acre-ft          6.5 kM3      combinations (Copeland et al. 1984). The
                                        Pamlico Sound              21,000,000   acre-ft        26    kM3      present day surface sediments of the estu-
                                            Pamlico River
                                            estuary                   662,308   acre-ft          o.82 km'     aries are composed primarily of fine sand,
                                            Neuse River
                                            estuary                1,082,306    acre-ft          1.34 kins    silts and clays. Pickett (1965) noted that
                                                                                                              fine sand covers most of the bottom of
                                    D. Avercige Depth                                                         Pamlico Sound, with silt present primarily
                                        Albemarle Sound                    16   ft               4.6 in
                                        Pamlico Sound                      16   It               4.9 in       in the deep areas of the northern basin and
                                            Pamlico  River estuary         11   ft               3.4 in       in the channels extending into the sound
                                            Neuse River estuary            12   ft               3.6 in

                        4                                                                                           Chapter I

                        from the mouths of the Neuse and Pamlico              Climate
                        rivers. Medium sand covers the higher                      North Carolina lies within a general
                        energy areas near shoals and the tidal                climatic region known as Humid Sub-
                        inlets from the ocean. Similarly, Pels (1967)         tropical. Moisture is adequate throughout
                        found the bottom sediments of Albemarle               the year to support forest as well as a
                        Sound to consist mainly of fine-to-medium             variety of agricultural crops, with only
                        sand around the margins of the sound,                 limited, localized needs for irrigation or
                        with a gradation southward to silt and clay           artificial drainage. Temperatures are
                        in the deepest areas.                                 moderate with long summers and brief
                                                                              winters. An extended summer drought
                                                                              may result from dominance ofthe Bermuda
                                                                              high pressure off the east coast. Warm,
                                                                              moist air from the tropics dominates sum-
                        Table 1.2. Water Budget for the Albemarle-            mer conditions while cooler, drier conti-
                        Pamlico Soundsystem (from Giese etal. 1979).          nental polar air controls winter weather
                                                                              (Gade and -Stillwell 1986).
                               Process                            Value            Dailymean air temperatures overmost
                                                                              ofeastern North Carolina and southeastern
                        Albemarle Sound                                       Virginia range between 5*C and 10*C in
                        A. Freshwater Inflow                                  January, the coldest month, and between
                             Chowan River                       4,600 cfs;    24'C and 270C in July, the warmest month.
                             Roanoke River                      8,900 cfs
                             Other                              2,900 cfs     Annual precipitation averages about 127
                             Total                             16,400 cfs     Cm/year throughout the basin, but in some
                        B. Precipitation on Albemarle                         years it may be very much lower or higher
                           Sound and associated open-                         than this. For example, at New Bern, NC,
                           water areas                          3,400 efs     the annual precipitation over the past 100
                                                                              years has ranged between 88 and 203 em/
                        C. Evaporation from Albemarle                         year (Wilder et al. 1978). In northeastern
                           Sound and associated open-                         North Carolina, evapotranspiration aver-
                           water areas                          2,600 cfs     ages about 86 em per year, and results in
                        D. Total outflow of Albemarle                         the return of roughly two thirds of the
                           Sound into Pamlico Sound:                          rainfall back to the atmosphere. Generally,
                           D=A+B-C                             17,200 efs     except in spring and early summer,
                        Pamlico Sound                                         precipitation exceeds evapotranspiration
                        A. Freshwater Inflow                                  (Wilder et al, 1978).
                             Tar-Pan-Aico River                 5,400 cfs
                             Neuse River                        6,100   cfs   Freshwater Inflows
                             Other                                 500  cfs       Mostofthe freshwater for the Albemarle
                           Total                               12,000   cfs   and Pamlico Sounds comes from four large
                        B. Inflow from Albemarle Sound                        rivers: the Chowan, Roanoke, Tar, and
                           to Pamlico Sound                    17,200   cf1s  Neuse. The Roanoke and Chowan, which
                                                                              are the two major rivers in the Albemarle
                        C. Precipitation on Pamlico Sound       8,250   cfs   basin, drain 25,035 kM2        and 12,802 kM2,
                        D. Evaporation from Pamlico Sound       5,740   cf.,  respectively, in northeastern North Caro-
                                                                              lina and southern Virginia. The Roanoke
                        E. Net inflow to Pamlico Sound:                       basin extends to the foothills of the Appala-
                           E=A+B+C-D                           31,710   cfs   chian Mountains. The Tar and Neuse

                         Profile of the Albemarle-Pamlico Estuarine System                                         5
                         Rivers, which supply most of the freshwater     Ocracoke, Hatteras, and Oregon Inlets.
                         to the Pamlico Sound, have watershed            This limited access, in combination with
                         areas equal to 11, 13 7 kM2 and 14,499 kM2'     the broad expanse of the sound, results in
                         respectively.                                   ocean tides being dampened to less than 6
                            The total freshwater discharge from          cm, except near the inlets (Roelofs and
                         theserivers into the Albemarle and Pamlico      Bumpus, 1953; Giese et al. 1979). Often,
                         Sounds cannot be measured, because the          wind-driven tides are dominant over lunar
                         low stream slopes and tidal influence near      tides in both the sound and adjoining trib-
                         the river mouths make measurement of            utary estuaries. The large size of Pamlico
                         stream flow by conventional techniques          Sound allows ample opportunity for wind
                         impossible in these areas. Consequently,        setup over long fetches. U.S. Geological
                         the most downstream gauging stations            studies in the Neuse and Tar-Pamlico estu-
                         operated by the U.S. Geological Survey lie      aries, summarized in Giese et al. (1979),
                         in the higher areas to the west. Wilder et      indicate these wind tides are normally in
                         al. (1978) showed that the data that are        the range of 0.3 to 0.6 m.
                         available from the gauging stations can be         The Albemarle Sound system has no
                         extrapolated to give reasonably accurate        direct outlet to the ocean. Instead, it
                         estimates of runoff from the whole              connects to Pamlico Sound and Oregon
                         Albemarle-Pamlico watershed. They found         Inlet through Croatan and Roanoke
                         that on a long-term basis, average flows on     Sounds; hence, dampeningof lunar tides is
                         a unit basis through all of the major rivers    even greater in the Albemarle than in the
                         are within narrow limits, ranging from          Pamlico. Normal wind tides in the sound
                         0.80 cubic feet per second (CFS) perMi2for      average about the same as in Pamlico
                         the Roanoke River to 1.05 CFS/mi2for the        Sound, and the water level can change
                         Neuse River. Thus, multiplication of these      relatively rapidly with shifting wind
                         unit discharge rates times the total basin      directions and velocities accompanying
                         area yields estimates ofthe total freshwater    frontal storm passage (Giese et al. 1979).
                         input.                                             On a short-term basis, wind driven
                             Giese et al. (1979) presented estimates     currents are often dominant over riverine
                         of inflow calculated by this method, along      flows in both the sounds and adjoining
                         with data on precipitation and evaporation,     estuaries. Within the estuaries, the velocity
                         in their detailed monthly and annual gross      of wind-driven currents may be increased
                         water budgets for the two sounds (Table         because of funneling effects. A second
                         1.2). The runoff is highest in the late         factor which contributes to the relative
                         winter and lowest in the late summer and        importance of wind-driven currents in the
                         fall. This is out of phase with the annual      system is that velocities due to freshwater
                         precipitation cycle described earlier (higher   inflow are low. Pamlico Sound and its
                         rainfall in the summer than in the winter).     estuaries are drowned river valleys. Con-
                         The explanation for the discrepancy is that     sequently, the river channels are oversized
                         evapotranspiration rates are much higher        for the amount of water they now carry,
                         in the summertime than in winter.               resulting in low velocities. In the long
                                                                         term, however, freshwater inflow is more
                         Tidal Exchange, Circulation, and                important than wind in affecting net flow
                         Flushing                                        because the effects of winds blowing from
                             Pamlico Sound is connected with the         various directions tend to cancel each other
                         ocean through several relativelysmall open-     over time. This is true throughout the
                         ings in the Outer Banks, primarily              Albemarle-Pamlico system (Giese et al.
                                                                         1979).

                       6                                                                                   Chapter I

                                                                         up to around 100 days for low flow condi-
                          180                                            tions (Figure 1.2). The average flushing
                          160                                            time, based on long-term flow data, is
                          140
                                                                         about 24 days for the Tar-Pamlico.
                          120-

                       2  100-1
                          So-                                            Salinity and Nutrients
                       z  60                                                 Salinities are generally lower in the
                       CO 40
                                                                         Albemarle system than in the Pamlico
                          20
                       L
                                                                         system for two reasons. First, the fresh-
                          0
                           0    2    4    6    8   10 12 14      16      water input:sound volume ratio for Albe-
                               FRESHWATER INFLOW (CFS X 1000)            marle Sound is larger than that for Pamlico
                       Figure 1.2.    Flushing times for the      Tar-   Sound. The higher current strength result-
                       Pamlico estuary as a function of river flow. Tar  ing from this more effectively blocks saline
                       River flow gauged at Tarboro, NC.                 water intrusion. Secondly, seawater that
                                                                         does reach Albemarle Sound has already
                                                                         been diluted in Pamlico Sound (Giese et al.
                          Giese et al. (1979) computed estimates         1979). Consequently, western Albemarle
                       of the replacement time for freshwater in         Sound is essentially a freshwater system,
                       the Albemarle and Pamlico Sounds by               and even the eastern-most areas of the
                       comparing the estimated freshwater input          sound typically have salinities less than 5
                       per month with the volumes of the sounds.         ppt. Pamlico Sound salinities decrease
                       On average, it would take about 11 months         from around 30 ppt near the barrier island
                       for the flow into Pamlico Sound to equal          inlets to approximately 15 ppt at the
                       the volume of the sound. Based on their           Pamlico River and Neuse River sub-estuary
                       monthly inflow estimates, the water               mouths (Giese et al. 1979; Stanley 1988b).
                       replacement times would vary between 19           Giese et al. (1979) contend that wind
                       and 6 months. Actually, the range is              velocity and direction are the dominant
                       greater than this because of extremes in          short-term influences on salinity in the
                       inflow that occur in some years. Similar          sounds, whereas variations in freshwater
                       estimates for Albemarle Sound range               inflows are the primary influence on the
                       between 9 and 3.5 months with a mean of           seasonal salinity patterns.
                       about 5.5 months. These estimates suggest            Salinity in turn influences to some
                       that the Albemarle flushes about twice as         extent the concentrations ofdissolved plant-
                       rapidly as the Pamlico.                           growth nutrients in the estuary. For
                          A more realistic estimate of estuarine         example, in the lower freshwater tidal
                       residence times requires taking into account      areas of the rivers, nitrate nitrogen (NO     3-
                       tidal exchange effects. To do so, one may         N) generally exceeds 20 AM, but decreases
                       use the method of Ketchum (1950) to calcu-        rapidly downstream with increasing
                       late the amount offreshwater in the estuary       salinity. Part of this decrease is due simply
                       based on the salinity of the system. One          to dilution by low-nitrate ocean water, so
                       then computes the amount of freshwater it         that in the open areas of Pamlico Sound,
                       would take to flush that freshwater from          the nitrate concentrations are probably
                       the system (Pilson 1985). Using this proce-       less than 1 AM most of the time. Other
                       dure, I calculated flushing times for the         forms of nitrogen and phosphorus also are
                       Tar-Pamlico River estuary as a function of        generally most concentrated in the upper
                       freshwater inflow. The results are that the       ends of the estuaries (Stanley 1988b;
                       residence times for this estuary range from       Bowden and Hobbie 1977; Hobbie and the
                       around 10 days under high flow conditions

                             Profile of the Albemarle-Pamlico Estuarine System                                                        7

                             Smith 1975). Of course, rates of biological            budgets, several general conclusions seem
                             uptake and remineralization, and rates of              obvious (Table 1.3). First, there are not
                             input from the watershed also are factors              drastic differences in the nonpoint areal N
                             regulating the estuarine nutrient concen-              and P loading rates from one basin to
                             trations. Because there are so many                    another. For N the range is from 216 kg/
                             dynamic processes affecting estuarine                  square km in the Tar-Pamlico to 365 kg/
                             nutrients, their concentrations vary widely,           square km in the Neuse. The nonpoint P
                             both spatially and temporally, and it is               loadingvaries from 21 kg/square km in the
                             difficult to generalize.                               Chowan to 33 kg/square km in the Neuse.
                                 Annual nutrient loading rates have                 Second, point-source N loading (on an areal
                             beenestimated forseveral oftheAlbemarle-               basis) is highest in the Neuse and lowest in
                             Pamlico sub-estuaries (NCDNRCD 1982,                   the Tar-Pamlico, but in all cases is only
                             1983,1987b). While detailed comparisons                about 20% of the total N load. Point
                             mustbe made with caution, since no uniform             sources contribute about half the total P
                             methodology was used to construct the                  loading, except in the Pamlico where they

                                         Table 1.3. Nutrient loading estimates for sub-basins of the Albemarle-
                                         Pamlico Sound system.

                                                                             N             N            P            P
                                         Basin                Land Area      Annual        Annual       Annual       Annual
                                                              (kM2)          Loading       Loading      Loading      Loading
                                                                             (kg/sq. km)   (kg x 10')   (kgtsq. km)  (kg x 101)

                                         Chowan               12,673                         4,197                       443
                                              Point                                            881                       165
                                              Nonpoint                         261           3,316          21           278

                                         Roanoke              25,063                         5,436                       486
                                              R.R. Res.       21,780                         3,845                       279
                                              Bel. Res.         3,283
                                                Point                                          593                       133
                                                Nonpoint                       303             998          22             73

                                         Tar-Pan-ilico        11,650                         3,223                       933
                                              Point                                            625                       201
                                              Nonpoint                         216           2,522          26           312
                                              Texasgulf                                          76                      419

                                         Neuse                15,979                         7,358                       962
                                              Point                                          1,513                       430
                                              Nonpoint                         365           5,845          33           532

                                         Total                65,365                       20,214                      2,824
                                              Point
                                              Nonpoint                         290                          27

                                         Notes:
                                         1. Roanoke and Chowan data from NCDNRCD (1982)
                                         2. Tar-Pamlico dat from NCDNRCD (1987)
                                         3. Neuse data from NCDNRCD (1983)
                                         4. "R.R. Res." refers to the Roanoke River Reservoir
                                         5. 'rexasgulF refers to discharge from the Texasgulf phosphate mining facility

                       8                                                                                        Chapter 1

                       are two-thirds of the total because of the           The population was overwhelmingly rural
                       large input from Texasgulf Chemicals,                at this time. There were only two small
                       which accounts for about one-half the total          urban areas, New Bern at the head of the
                       P going into the Tar-Pamlico. Finally,               Neuse River estuary and Raleigh in the
                       except for the Tar-Pamlico phosphorus load-          upper Neuse basin. Each had about 4,500
                       ing, none of the Albemarle-Pamlico tribu-            inhabitants.
                       tary areal loading rates are unusually high               Since 1850 there has been only modest
                       in comparison to other U.S. river basins for         population growth in the Chowan Basin,
                       which estimates have been made (e.g.,                but much more rapid growth in the
                       Clesceri et al. 1986; Rast and Lee 1983).            Roanoke, Tar-Pamlico, and Neuse basins
                                                                            (Figure.1.3). In 1987, it was estimated that
                       Principal Uses                                       2.37 million persons lived in the Albemarle-
                       Settlement and Population Growth                     Pamlico basin, with most of these in the
                           The Albemarle-Pamlico region was the
                       first area of North Carolina to be settled by        to 2500 - -------- ------- ---
                                                                            a
                       Europeans, but the development proceeded             z
                                                                            9  20M -
                       slowly until recent times, so that at present        5
                                                                            0  1500-
                       the area remains one of the State's most             I
                       rural. Sir Walter Raleigh explored the               z
                                                                            0
                       Pamlico Sound, landing at Roanoke Island
                       in 1584. In 1587, Raleigh appointed John                  0           Will                MR  MR MR
                                                                            0     1790 1810 1830 1850 1870 1890 1910 1930 1950 1970 1087
                       White governor of what was to become the             a'
                       "Lost Colony" on Roanoke Island. Settle-                                     YEAR
                       ments in the Jamestown, Virginia area                           Chowan       Roanoke M Tar
                       after 1607 became the nucleus for the                           Neuse        Coastai
                       colonization of northeastern North Caro-
                       lina. Early communities began north of               Figure 1.3. Growth ofhumanpopulation in each
                       Albemarle Sound in the mid and late 1600s,           ofthe mcjorAlbemarle-Pamlico estuarine system
                       and migration farther south led to the               sub-basins.
                       establishment of the town of Bath on the
                       Pamlico River estuary in 1704. At the time
                       of the first United States census in 1790,
                       the total basin population was about                                                 Roanoke
                       380,000. The Roanoke and Chowan sub-                                     --           24796
                       basins in the northeastern part of North                                        36%
                       Carolina and southern Virginia contained                Neuse
                       about three-fourths of the total, with                  14306     21%
                       140,000 and 100,000 inhabitants, respec-
                       tively (Figure 1.3).                                                                 10%
                          Southern and western migration con-                                18%       15%          Coastal
                       tinued with the founding of New Bern at                                                       7025
                       the head of the Neuse estuary in the early
                       18th century (Lefler 1965). By 1850 there                   Chowan                    Tar
                       were over 600,000 persons in the basin,                      12730                   10448
                       with most of the growth having occurred in           Figure 1.4. Distribution of Albemarle-Pamlico
                       the western Roanoke basin and in the Tar-            land areas (square kilometers) among the major
                       Pamlico and Neuse basins to the south.               sub-basins.
                                                                                                            10%

                          Profile of the Albemarle-Pamlico Estuarine System                                           9

                          Roanoke and Neuse basins.                        no effect from seasonal visitors (Tschetter
                              Most areas immediately adjacent to           1989).
                          the Sounds are sparsely populated in
                          comparison to more inland areas. For             Land Use
                          example, although 10% of the Albemarle-             Current land use patterns in the
                          Pamlico watershed drains directly into the       Albemarle-Pamlico also reflect its rural
                          sounds (i.e., is downstream from the mouths      nature. The region is predominantly for-
                          of the four major rivers), those "coastal"       ested and agricultural (Figure 1.5). Forest
                          areas contain only about 5% of the total         lands comprise 60% of the total basin area,
                          basin population today (Figures 1.3 and          and about 20% of the land is in crops. The
                          1.4). However, present growth rates in           percentage of the basin that is urbanized is
                          three of the coastal counties - Dare,            estimated to be no more than about 2%.
                          Currituck and Carteret - are among the           There are modest differences in land use
                          highest in the State, and this trend is          among the sub-basins of the system (Figure
                          projected to continue in the near future         1.6). The forest land coverage ranges from
                          (Tschetter 1989). Nevertheless, the              54% in the Neuse River, Tar-Pamlico River,
                          Albemarle-Pamlico basin in general, and          and Albemarle Sound "coastal" basins to
                          the immediate coastal area in particular,        63% and 67% in the Roanoke River and
                          continue to be more rural than areas             Chowan River basins, respectively. Con-
                          surrounding most of the large estuaries          versely, the cropland acreage is highest in
                          farther north along the Atlantic coast.          the Neuse, Tar-Pamlico and Albemarle
                              The coastal counties experience wide         Sound regions (25-28%) and lowest in the
                          fluctuations in population due to seasonal       Roanoke River basin (14%). The Neuse
                          tourism. Tschetter (1989) estimated that         Basin as a whole is more urban (4%) than
                          Dare Countys population increased to over        any of the other sub-basins, but of course
                          4 times that of the permanent population         almost all of this is in the upper end of the
                          during the peak seasonal day in 1987.            basin, in the Raleigh-Durham area.
                          Other coastal counties and some counties
                          on the west side of the sound experience         Commercial Fisheries
                          smaller population fluctuations, perhaps             The Albemarle-Pamlico system is a
                          in the 20-50 percent range. Counties farther     major contributor to the commercial fish-
                          inland in the AP basin experience little or      eries catch in North Carolina, as evidenced
                                                                           by the fact that about 80% of the total
                                                                           edible harvest each year is landed there.
                                                                           Pamlico Sound is very different from
                                    Forest
                                     W%                                    Albemarle Sound, however, both in terms
                                                                           of the commercial catch poundage and the
                                                               Pasture     composition of the catch. It has been
                                                                5%         estimated that in 1980, for example,
                                                                           Pamlico Sound contributed 78% ofthe total
                                                              Other        inshore catch, in contrast to Albemarle
                                                               14%         Sound, which contributed only 14% of the
                                    Uxrban                                 total commercial catch (Copeland et al.
                                     2%           Crops                    1984).
                                                  20%                          Freshwater and anadromous species of
                          Figure 1.5.   Land use within the Albemarle-     finfish dominate the catch in Albemarle
                          Pamlico estuarine system watershed (1985).       Sound and its tributary rivers, the Chowan

                          1 0                                                                                                   Chapter I

                                           Albemarle River                                               Chowan River

                                             Forest
                                             54%
                                                                                                 Forest
                                                                                                  67%

                                                                       Pasture                                                      Pasture
                                                          .......................
                                                                                                                                       3%
                                                                         1%

                                Urban
                                 0%                                                                                                 Other
                                                                       Other                                                         11%
                                                                       17%

                                         Crops                                                          Urban           Crops
                                         28%                                                             0%              19%

                                             Neuse River                                                 Pamlico River

                                          Forest                                                        Forest
                                           54%                                                          59%

                                                                       Pasture                                                     Pasture
                                                                        3%                                                            1 %

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

                                Urban                                  Other
                                 4%                                    15%                                                     Other
                                                                                                     Crops                      26%
                                            Crops                                                    15%
                                             25%

                                           Roanoke River                                              Tar-Pamlico River

                                                                                                       Forest
                                  Forest                                                                54%-
                                  63%
                                                                       Pasture
                                                                        8%                                                         Pasture
                                                                                                                                      3%

                                                                       Other                 Urban                                 Other
                                                                       13%                     1 %                                 15%

                                            Urban          Crops                                         Crops
                                             2%             14%                                          26%

                         Figurel.6. Land use within each ofthe mqjor sub-basins of the Albemarle-Pamlico estuarine system
                         watershed.

                           Profile of the Albemarle-Pamlico Estuarine System                                              1 1

                           and the Roanoke, where most of the catch          Ross 1986; Godwin et al. 1971).
                           is made during the spring spawning runs.              Farther south, in Pamlico Sound and
                           In recentyears the most important anadro-         its tributary estuaries, the commercial
                           mous species have been the alewife (Alosa         catch consists primarily of blue crabs
                           pseudoharengus) and blueback herring              (Callinectes sapidus), white, brown and
                           (Alosa aestivalis). In the official landing       pink shrimp (Penaeus sp.), oysters
                           statistics of the National Marine Fisheries       (Crassostrea virginica), hard clams
                           Service, these two species are combined as        (Mercenaria mercenaria), bay scallops
                           "alewives." Another common name is "river         (Argopecten irradians), and seasonally
                           herring" (Godwin et al. 1971). American           abundant species ofedible marine finfishes.
                           shad (Alosa sapidissima) and striped bass         These include grey seatrout, or "weakfish"
                           (Morone saxatilis) are two other anadro-          (Cynoscion regalis), flounder (mostly Para,
                           mous species in the Albemarle. The shad           lichthys dentatus and P. lethostigma),
                           were once very abundant, but the catch            Atlantic croaker (Micropogon undulatus),
                           declined drastically in the early 1900s.          bluefish (Pomatomus saltatrix), spot
                           Striped bass is perhaps the best known,           (Leiostomus xanthurus) and mullet (Mugil
                           and certainly the most studied, finfish in        cephalus and M. curema).
                           theAlbemarle region. Amodest commercial               Between 1980 and 1987, the annual
                           fishery for resident species of catfish and       landings of edible finfish in the Albemarle-
                           bullheads (genus Ictalurus) has developed         Pamlico system averaged 57.3 million
                           in the last 25 years or so (Epperley and          pounds, and the shellfish harvest averaged

                            Table 1.4. Albemarle-Pamlico Commercial landings catch composition (1980-1987 auerages).
                            Data are from N.C. Diuision of Marine Fisheries (1980-1987).

                                                                             % oftotal       % of finfish     % of shellfish
                            Species                          lbs/year          catch             catch            catch

                            Edible Finfish                   57,298,432        60.2
                              1.  Grey Seatrout              12,325,898        12.9              21.6
                              2.  Flounder                   10,071,075        10.6              17.6
                              3.  Croaker                     9,678,043        10.2              16.9
                              4.  Alewives                    6,578,158          6.9             11.5
                              5.  Bluefish                    4,180,627          4.4              7.3
                              6.  Spot                        3,593,872          3.8              6.3
                              7.  Mullet                      1,312,485          1.4              2.3
                              8.  Catfish                     1,108,679          1.2              1.9
                              9.  American Shad                 261,034          0.3              0.5
                              10. Striped Bass                  230,140          0.2              0.4
                              11. Other                       7,958,421          8.4             13.8

                            Shellfish                        37,876,224        39.8
                              1.  Blue Crabs                 30,311,632        31.8                                80.0
                              2.  Shrimp                      4,969,160          5.2                               13.1
                              3.  Hard Clams (meat)             846,452          0.9                               2.2
                              4.  Oysters (meat)                633,781          0.6                               1.4
                              5.  Bay Scallops (meat)           533,781          0.6                               1.4
                              6.  Other                         962,270          1.0                               2.7
                                  (Squid, Sea Scallops)

                    1 2                                                                              Chapter I
                    about 38 million pounds (Table 1.4). Four       Sounds remains largely unknown. Other
                    species -grey seatrout, flounder, croaker       than for striped bass, there are essentially
                    and alewives - account for about two-           no historical ecological data upon which to
                    thirds of the total edible finfish harvest.     base recreational fishing trend analyses.
                    Averaging 30 million pounds landed per
                    year, blue crabs have dominated the shell-      Industry and Ports
                    fish landings (80% of the total), and are the       North Carolina is currently the nation's
                    most abundant single species in the entire      eighth largest state in manufacturing em-
                    commercial edible harvest (32%). About 5        ployment. Manufacturing is fairly uni-
                    million pounds of shrimp are landed             formly distributed throughout the state
                    annually, along with lesser quantities of       except in two areas where it is much less
                    hard clams and other mollusks (.25-1            intense: the southwestern Mountain and
                    million pounds per year).                       northeastern Tidewater areas (Gade and
                       Atlantic menhaden (Brevoortia                Stillwell 1986). Large firms (with over 250
                    tyrannus) is an industrial finfish species      employees) are especially scarce in the
                    that spends part of its life in the estuaries   Albemarle-Pamlico region; in 1980, there
                    but is harvested offshore in theAtlantic. In    were fewer than 30 of them in the 14
                    terms of volume, no other fishery in North      counties adjacent to the Sounds (Wilms
                    Carolina has ever come close to menhaden        and Powell [no date given]). In fact, there
                    (Whitehurst 1973). In 1984, 178 million         are only three large water-dependent
                    pounds of menhaden were landed at North         manufacturing plants that discharge
                    Carolina ports (North Carolina Division of      directly into an estuary of the Albemarle-
                    Marine Fisheries 1984).                         Pamlico system. Two are Weyerhaeuser
                                                                    pulp and paper mills; one on the lower
                    Recreation                                      Roanoke River at Plymouth, NC, and
                       Tourism, already one of North Caro-          another above New Bern, NC, on the lower
                    lina's larger industries, is projected to grow  Neuse River. The third is a phosphate
                    even larger in the near future, surpassing      mine and manufacturing plant owned by
                    three ofthe States traditional major indus-     Texasgulf Inc. on the south shore of the
                    tries: tobacco, textiles, and furniture. Dare   Pamlico River estuary.
                    County is by far the leader in tourism in the       In the early 1950s, large deposits of
                    coastal region. Revenues there have in-         phosphate were discovered in Beaufort and
                    creased at an explosive rate fromiust $11.6     Hyde Counties. The deposits were formed
                    million in 1971 to nearly $350 million in       25 million years ago as thick layers ofsmall
                    1987 (both figures adjusted to 1984 dollars)    calcium phosphate pellets; theywere subse-
                    (Tschetter 1989).                               quently covered with up to 30 meters of
                       Fishing was the first major water-           sand and clay. By 1966, the Texas Gulf
                    related recreational activity to develop in     Sulphur Company (now Texasgulf, Inc.)
                    the Albemarle-Pamlico region, and today,        mine was in full-scale operation in an area
                    recreational fishing is a major activity in     immediately adjacent to the Pamlico River
                    the coastal region (see Chapter 7). Recent      near Aurora, NC. At the Aurora facility
                    studies have quantified it in social and        Texasgulf concentrates the ore and uses
                    economic terms (Johnson et al. 1986). Also,     part of it in the manufacture of phosphoric
                    Johnson and Perdue (1986) estimated the         acid. The rest is sold to fertilizer manu-
                    marina and marine manufacturing income          facturers. The plant also discharges phos-
                    attributable to recreational fishing. Unfor-    phorus and fluoride enriched freshwater
                    tunately the ecological impact on the           into the estuary. Controversy surrounding

                          Profile of the Albemarle-Pamlico Estuarine System                                           1 3

                          the impact of Texasgulf on the Pamlico           Philadelphia, etc.
                          River has grown steadily over the past               Pamlico River tonnage rose rapidly in
                          decade. The company's reputation has             themid-1960s, coincident withtheopening
                          been tarnished by a series of Clean Air Act      ofthe Texasgulfphosphate mine, and today
                          violations and small-scale chemical spills,      about half of the total Albemarle-Pamlico
                          some of which have led to hefty fines.           waterborne commerce is related to the
                          Today fisherman and other local citizens,        mine. Liquid sulphur (17% of the total
                          along with some North Carolina state offi-       tonnage) is brought to the Texasgulf plant
                          cials and scientists, suspect that the dis-      and fertilizer materials (34% of the total)
                          charges are responsible for widespread           are barged south to Morehead City for
                          damage to the estuary, but so far, the           shipment out of the region. The third
                          evidence is mostly circumstantial.               largest cargo in the sounds is pulpwood
                              The Albemarle-Pamlico probably has           (25% of total tonnage) en route to mills on
                          the lowest amount of port activity of any        the lower Neuse and Roanoke Rivers and
                          estuarine system, in its size category, in       upstream in the Chowan River.
                          the nation. The only ports of any signif-            The fact that no significant port develop-
                          icance in North Carolina are to the south,       ment occurred in the Albemarle-Pamlico
                          at Morehead City and at Wilmington.              region has been attributed to the difficulties
                          Waterborne commerce, as reflected by ship-       of navigating the shallow, shifting inlets
                          ping tonnage, is trivial in the sounds. In       through the Outer Banks and the large
                          1984, only 2 million tons of waterborne          expanse of shallow waters between the
                          cargo were transported in the all of the         Banks and the mainland to the west (Gade
                          sounds and rivers in the Albemarle-Pamlico       and Stillwell 1986). Poor transportation
                          system (Morehead City port activity not          between the coastal counties and other
                          included). By way of comparison, during          regions of the state may have been a factor
                          the same year the Port of Wilmington, NC,        also, but of course it is difficult to ascertain
                          alone handled about three times as much          whether this was primarily a cause for, or
                          cargo. And Wilmington is a very smal I port      effect of, the lack of port development.
                          in comparison to Charleston, Norfolk,

                           CHAPTER2

                           Major Environmental Concerns

                               During the past decade, concerns about          A decade after the environmentalmovement
                           the environmental health of various parts           spawned a great surge of new laws and
                           the Albemarle-Pamlico system have been              commitments to clean up and protect
                           voiced more and more frequently in                  threatened resources, the people ofNorth
                           magazine and newspaper articles, on                 Carolina are losing the battle against water
                           television news reports, and by environ-            pollution. Meanwhile, the life ofour coastal
                           mental groups, scientists and government            waters continues to ebb away, choking on
                           agency personnel. At the present time, the
                           estuary is being studied more intensively           mud, algae, chemical poisons and the
                           than ever before because of the U           . S.    threat and promise of ever more. State
                           Environmental Protection Agency's on-               regulators say the pollution problems
                           goingAlbemarle-Pamlico Estuarine Study              confronting the coast are so complex, they
                           (APES). The APES 5-Year Study Plan                  are strugglingiust to understand them, let
                           (NCDNRCD 1987b) lists a number of so-               alone implement controls.
                           called "major environmental concerns" for                                    P. Haskins (1981)
                           the Albemarle-Pamlico. A draft Status
                           and Trends Report for the Albemarle-             documented in 1980,         1981, and 1983
                           Pamlico estuarine system includes much           (Christian et al. 1986). The Chowan blooms
                           more detailed information on some ofthese        were largely composed of the nitrogen-
                           topics (Copeland 1989). The followingsum-        fixing species Aphanizomenon flos aquae,
                           mary is based, in part, on material from         Anabaena spiroides and Anabaena flos
                           that document. Several ofthe concerns are        aquae, while in the Neuse Microcystis
                           addressed in other Chapters of this report;      aeruginosa has been the dominant blue-
                           hence, they are discussed only briefly here.     green (Paerl 1982, 1987).
                                                                                Fortunately, the blooms have been
                           Eutrophication - As                              limited to the riverine and freshwater tidal
                           Evidenced by Blue-Green                          portions of the estuaries because the blue-
                           Algal Blooms                                     green species comprising them cannot
                               Blooms of noxious phytoplankton are          tolerate saltwater. In the Chowan, the
                           often a very obvious indication of cultural      blooms extended over a 30 km stretch
                           enrichment of estuarine waters with              between Holiday Island and the river's
                           nutrients, primarily nitrogen and phos-          mouth near Edenton, NC. The Neuse
                           phorus. Such blooms have occurred during         blooms persist for a period ranging from
                           some, but not all, recent summers along          several weeks to months. Chlorophyll a
                           the lower Chowan and Neuse Rivers. The           levels typically are several hundred /ig(
                           most spectacular blooms in the Chowan            liter (NCDNRCD 1982; Christian et al.
                           occurred in 1972, 1978, and 1983                 1986).
                           (NCDNRCD 1987b). Neuse blooms were                   Research has improved our knowledge
                                                                            ofseveral factors contributingto the blooms,

                    1 6                                                                               Chapter 2

                    but scientists have not yet integrated all      and more regularly, than any other estuary
                    the information needed to explain when          in North Carolina (Stanley 1988b). In fact,
                    and where the blooms will occur. The            it is one of the few areas of the Albemarle-
                    relationship between increased nitrogen         Pamlico system for which there is a complete
                    and phosphorus and blue-green blooms is         enough record to permit an analysis of
                    well established for freshwater lakes, but      historical trends (see Chapter 4).
                    is not nearly so well understood for estuaries
                    like the Chowan and Neuse. Generally,           WetlandS LOSS
                    estuarine algal growth is considered to be          Although the Albemarle-Pamlico region
                    more nitrogen limited than phosphorus           is relatively undeveloped, human activities
                    limited (Boynton et al. 1982), but trying to    in the area have altered and destroyed
                    quantify this has proven very difficult, for    habitats that are part of, or tightly-linked
                    several reasons. For one thing, the flo,        to, the estuarine ecosystem. Dredging,
                    through nature ofestuaries causes them to       draining and f illing are the activities caus-
                    behave like rivers sometimes, when              ingmost ofthe changes and these activities
                    freshwater input is high, and like lakes at     are usually associated with one of three
                    other times when inflow is low. This hydro-     industries: agriculture, residential housing
                    logic variability causes problems in predict-   development, or commercial forestry.
                    ing water and nutrient flushing rates, as       Reproductive, migratory and feeding pat-
                    well as algal concentrations. For the Neuse,    terns for a wide variety of aquatic and
                    Christian et al. (1986) showed that blue-       terrestrial organisms are thought to be
                    green blooms could not form unless water        affected, but details are lacking for most
                    temperature is high and river discharge is      species. Thus, the relative values of the
                    low, because otherwise the water is swept       wetlands are poorly known and, in most
                    into Pamlico Sound before the blue-green        cases, restoration or mitigation forimpacted
                    algae densities have time enough to build       areas has yet to be evaluated on an economic
                    up to bloom levels. This probably explains      basis.
                    why blooms develop only in low-flow                 Adams et al. (1989) recently prepared
                    summers, despite the fact that plenty of        a report on the status and trends of the
                    the nutrients are present every year.           wetlands in the Albemarle-Pamlieo region;
                       There is much uncertainty whether the        some of their findings are summarized
                    blue-green problem is worse now than in         below.
                    past decades. It is said that the blooms are        A. Tidal Salt Marshes: In 1962, there
                    more frequent now (e.g., NCDNRCD 1987b),        were estimated to be a total of 4,897 hect-
                    but there is no historical systematic sam-      ares of salt marsh in Pamlico Sound, and
                    pling record to confirm this. It is certainly   none in the Albemarle Sound. Most of the
                    possible that blooms werejustas common          marsh area was in Carteret County (83%),
                    earlier, but, like most other symptoms of       with the remainder in Hyde (13%) and
                    environmental degradation, were paid little     Dare (4%) Counties (Wilson 1962). Amore
                    attention. This is unfortunate, because         recent estimate is not available. Tidal salt
                    such a record would give support to the         marshes are ofdirect benefit for humankind
                    popular opinion that reduction of nutrient      due to their function in supporting finfish
                    loading (and presumably nutrient concen-        and shellfish fisheries, waterfowl popula-
                    tration) in the estuaries will reduce or        tions, and aesthetics. These benefits have
                    eliminate the blooms in the future.             been appreciated for at least three decades;
                       The Pamlico River Estuary has been           thus, salt marshes are afforded a relatively
                    monitored for nutrients and algae longer,

                          Major Environmental Concerns                                                               1 7
                          high level of protection in most states,         which has a long history of water quality
                          including North Carolina.                        problems and is undergoing rapid develop-
                              B. Nontidal Brackish Marshes: These          ment and land use changes. It is thought
                          are eight times as extensive as salt marshes     to be functionally similar to the nontidal
                          in Pamlico Sound; in 1962, there were            brackish marsh, although obviously the
                          about 40,000 hectares. Carteret County           plant and animal species composition is
                          had 15,621 hectares (39% of total), and          somewhat different. Where it is abundant,
                          most of the rest was in Hyde, Pamlico and        much importance is given to waterfowl and
                          Dare Counties (Wilson 1962). Tradition-          sports fishing resources. A relatively large
                          ally, these marshes have been altered to         number of permits were issued allowing
                          create impoundments to attract waterfowl,        alteration of wetlands in the Currituck
                          with little attention being paid to the costs    Sound area between 1970 and 1984 (Stock-
                          of such alteration. Despite their large          ton and Richardson 1987). The proximity
                          areal coverage, less is known about the          of this area to a major metropolitan area
                          ecological functioning of these marshes          (Norfolk and Virginia Beach, Virginia)
                          than is known for tidal salt marshes. In         makes it very attractive for outdoor recre-
                          addition, large areas of marsh were altered      ation and development of second homes.
                          in the past by digging ditches for mosquito          E. Riparian lAlluvial Forested Wet-
                          control, a practice that elicited a call for a   lands: North Carolina and other southern
                          moratorium on ditching (Kuenzler and             states have extensive forested wetlands.
                          Marshall 1973). The ditching no longer           There are several types, including bottom-
                          occurs, but the potential for these areas to     land hardwood forests along rivers and
                          recover to their original, unaltered condition   streams, cypress strands, willow strands,
                          is not known. The brackish marshes are           and small headwater branches and drains.
                          protected by the same mechanisms used            Functionally, however, they have many
                          for other wetlands.                              similarities. One is their capacity to act as
                              C. Fringe Swamps: These are forested         water pollution filters. A very good syn-
                          wetlands that occupy the shorelines of           thesis of past research on this subject was
                          Albemarle Sound and the mouths of some           made by Kuenzler (1989). He found that
                          of its major tributaries. They represent a       those alongstrearns can remove large quan-
                          transition between aquatic ecosystems and        tities ofsuspended sediments from cropland
                          interior wetlands. Near the shoreline,           runoff as well as nitrogen and phosphorus
                          they are characterized by groves of dead or      from both point sources and nonpoint
                          dying cypress trees under permanently            sources of pollution. For example, it was
                          flooded conditions, a very common - and          estimated that the systems removed 64%
                          picturesque - sight in the Albemarle             of the total nitrogen and 43% of the total
                          region. Brinson (1989) estimates that they       phosphorus from upland sources in the
                          occupy about three-fourths of the southern       Chowan River watershed (Kuenzler and
                          shoreline of Albemarle Sound and almost          Craig 1986).
                          all the shoreline of the Alligator River.           These wetlands have been destroyed
                          They were harvested for timber in the            rapidly in recent decades. Turner et al.
                          past, but no studies have been made to           (1981) reported the combined loss of 30,000
                          document the effects of the harvesting on        acres ofbottornland hardwood forests from
                          the ecology of the swamps.                       about 1960 to 1975 in North Carolina and
                             D. Nontidal Freshwater Marsh: Most            South Carolina. Such losses represent a
                          of this marsh type (3,500 hectares) occurs       small fraction of the total forest land so
                          in the northern part of Currituck Sound,         that they are not reflected by the statistics

                    1 8                                                                           Chapter 2

                    in total forest land acreage trends (see      Currituck Sound (Adams et al. 1989). In
                    Chapter 3). Nevertheless, the decrease        terms of present conditions, Brinson and
                    represents a substantially larger fraction    Davis (1989) carried out one of the most
                    of the total wetland area. Such reductions    recent surveys and found great variability
                    must be affectingwater quality, given their   in SAV abundance from one area to another.
                    high pollutant removal capacities. The            The marine SAV community in the
                    National Wetlands Policy Forum is develop-    Albemarle-Pamlico system appears rela-
                    ingrecommendations designed to stop, then     tively stable, according to Thayer et al.
                    reverse, wetland losses. (Kuenzler 1989).     (1984). Eelgrass, a major component of
                    Implementation of these and other policies    this community, recovered substantially
                    developed by Federal and State authorities    from the wasting disease of the 1930s.
                    mayturn.out tobe one ofthe most important     However, there is concern about future
                    estuarine water quality management            development activities that might affect
                    actions in the near future.                   SAV habitat, and about clam-kicking, a
                                                                  mechanical clam harvesting procedure
                    Loss of Submerged Aquatic                     which is thought to damage SAV (Peterson
                    Vegetation                                    et al. 1983, 1987).
                       Reduction in submerged aquatic vegeta-     Declines in Fisheries
                    tion is of crucial environmental concern
                    because a decline represents a reduction in       Declines in commercial fisheries have
                    fisheries and waterfowl habitats. In the      occurred in the Albemarle-Pamlico region
                    mid-1970s and before, submerged aquatic       following historic highs in the 1970s. For
                    vegetation (SAV) was common in the upper      nearly 40 years, the total finfish catch
                    half of the Pamlico River estuary (Davis      remained relatively stable. But between
                    and Brinson 1976). By 1985, however,          1968 and 1981, it rose dramatically to
                    biomass had been reduced to about 1% of       about three times what it had been pre
                    that of the 1970s and only widgeongrass       viously. Since then, it has fallen back to
                    was present (Davis and Brinson 1989). An      about 1.5 times the 1930-1970 mean. It is
                    after-the-fact analysis of the decline sug-   this short-term decline in the past 8 years
                    gests that unusual weather conditions in      that has caught the attention of many
                    1978 contributed to the problem.        Any   people, and it has been widely publicized.
                    tendency toward reestablishment of            Similarly, the total commercial shellfish
                    Vallisneria canericana (wild celery), previ-  harvest rose gradually until the late 1960s,
                    ously the most important species in the       fell back slightly in the early 1970s, then
                    estuary, probably was negated by ex-          began a very steep increase in the late
                    tremely high salinities prevalent in 1981     1970s, reaching an all-time high in 1979
                    (Davis and Brinson 1989).                     that was about twice the average for the
                       The decline of SAV in the Pamlico River    preceding two decades. But again, it has
                    has been mentioned frequently in discus-      been the decline since 1980 (down to about
                    sions of the problems in the Albemarle-       1.5 times the 1950-1970 mean) that has
                    Pamlico, and it is usually compared to the    been the focus of attention. Trends for
                    SAV decline documented in the Chesapeake      individual fisheries are very mixed, with
                    Bay (Orth and Moore 1982). There has          some commercial catches risingat the same
                    been a tendency to extrapolate the Pamlico    time others were declining. For example,
                    situation to other areas of the sounds. But   since 1950, blue crab landings have
                    actually, there is no historical evidence on  doubled, shrimp landings have shown little
                    SAV abundance for any other region except     trend (but have displayed great inter-

                           Major EnvIronmental Concerns                                                              1 9

                           annual fluctuations), while oysters have        other fish species examined during the
                           declined. Flounder, croaker, and spot           study were infected (Noga et al. 1989).
                           landings all skyrocketed in the early 1970s,        No primary causes for the diseases
                           and since 1980 have fallen back, but remain     have been established. The current working
                           high in relation to the long-term means.        hypothesis is that environmental stress
                           Anadromous species generally have de-           increases the susceptibility of the fishes to
                           clined, either on a long-term, more-or-less     the diseases. Salinity, in particular, is one
                           continuous basis (alewives and American         factor that is being examined, but to date
                           shad), or in recentyears followingan earlier    there have been no controlled experiments
                           increase (striped bass and catfish). The        performed to test a specific hypothesis.
                           fishery declines are generally attributed to        Another widely publicized perception
                           a combination of over-fishing declining         in North Carolina is that the number of
                           water quality, and critical habitat loss or     fish kills in the estuaries has increased in
                           alteration (NCDNRCD 1987b). Reasons for         recent years. Once again, unfortunately,
                           the earlier increases in harvest are seldom     there is no program to sample system-
                           discussed. Trends in commercial fisheries       atically; rather, the number of kills reported
                           are covered in more detail in Chapter 7 of      toauthorities is thebasis forthis conclusion.
                           this report.                                    Most reported kills occur in the Pamlico
                                                                           River, and menhaden are most often the
                           Fish Diseases and Kills                         species involved (see Chapter 5). The most
                              Episodes of infectious diseases that are     frequent cause given by State agency scien-
                           associated with the presence of some            tists for the kills is low dissolved oxygen in
                           microbes or parasites have been observed        the bottom waters of the estuary (Stanley
                           in the Albemarle-Pamlico system, as well        1985). Many feel that bottom water anoxia
                           as elsewhere along the U.S. east coast. A       is more common in the Pamlico now than
                           "red sore" disease reached epidemic pro-        in the past, even though the available data
                           portions in some commercial species in          for the past 20 years suggests otherwise
                           Albemarle Sound during the 1970s (Esch          (see Chapters 4 and 5).
                           and Hazen 1980). In the Pamlico River
                           estuary, the most prevalent of these prob-      Impairment of Nursery Area
                           lems seems to be ulcerative mycosis (UM),       Function
                           a fungal infection (Noga et al. 1989). The          Initial development of the post-larval
                           perception that these diseases are more         stages of many fish and shellfish species
                           serious nowthan in the past is not strongly     occurs in primary nursery areas (PNAs)
                           debated, despite the lack of any long-term      located in the uppermost areas of estuaries
                           systematic monitoring record. A recent,         and their tributaries. The marshes and
                           two-year monitoring effort (1985-1987) was      small embayments fringingAlbemarle and
                           conducted in the Pamlico River to assess        Pamlico Sounds provide essential nursery
                           the occurrence and species distribution of      functions for a majority of the commercial
                           ulcerative mycosis. Overall, 16% of the         species in the North Carolina coastal area.
                           menhaden sampled had UM lesions, but            Because of their location, PNAs are very
                           there was a strong seasonality in disease,      sensitive to activities on adjacent uplands.
                           with the highest incidences occurring in        Freshwater drainage, land-use changes
                           the Spring and Fall. At those times, up to      and eutrophication can jeopardize the
                           100% of the menhaden in individual trawl        functional aspects ofthe primary nurseries.
                           samples were infected. Less than 1% Of          However, the exact extent of impairment

                     2,0                                                                               Chapter 2

                     apparently is difficult to estimate, even        area, but Core Sound and Bogue Sounds
                     when historical data are present. For            are affected (See Chapter 7 for more details).
                     example, in North Ca    *rolina, the Wildlife    New techniques to more accurately mea-
                     Resources Commission, the Division of            sure contamination and potential human
                     Marine Fisheries, and university research-       impact are needed so that management
                     ers have collected information concerning        can more effectively allocate shellfish
                     abundance of juvenile fishes in PNAs of          resources. Relationships between contami-
                     Pamlico Sound for some two decades, but          nation and land-use characteristics are
                     there has never been a definitive analysis       poorly understood.
                     of environmental or fish population trends
                     in the nursery areas (Adams et al. 1989).        Toxicant Effects
                        The nursery areas are defined, for               Very little is known about the effects of
                     management purposes, on the basis of the         toxicants on estuarine organisms or the
                     numbers of juvenile fishes caught in a           distribution of toxic substances in the
                     standardized samplingroutine. Suchdesig-         Albemarle-Pamlico Estuarine System. A
                     nated areas are protected against damag-         preliminary report has just been issued on
                     ing fishing practices through regulations        the first-ever systematic survey of
                     of the Marine Fisheries Commission and           Albemarle-Pamlico sediment heavy metals
                     enforced by the Division of Marine Fish-         concentrations. This report deals with the
                     eries. Trawling, as well as oyster and clam      Pamlico River estuary, the first of foursub-
                     kicking (using propeller wash to excavate        regions to be sampled over the next several
                     clams) are prohibited in such areas. Impacts     years (Riggs et al. 1989). The results of the
                     from land use activities are less well-con-      report are summarized in Table 2. 1. The
                     trolled, and there is suspicion that in the      authors of the report concluded that the
                     future, these activities will pose the most      low metals concentrations within Choco-
                     serious threats to the long-term health of       winity Bay surface sediments are similar
                     the nursery areas. More specifically, the        to concentrations occurring in subsurface
                     greatest weakness in existing regulatory         samples throughout the Pamlico (data not
                     programs is thought to lie in controlling        shown). The subsurface samples are inter-
                     non-point sources of water pollution and in      preted to represent the natural background
                     regulating development landward of the           during preindustrial conditions. If this is
                     nurseries (Adams et al. 1989).                   the case, then the Chocowinity Bay sedi-
                                                                      ments show little metals enrichment from
                     Shellfish Closures                               man's activities. On the other hand,
                        Closure due to pathogenic microbial           averages for all the Pamlico samples were
                     contamination of shellfish waters in North       about twice those for Chocowinity Bay,
                     Carolina has remained relatively constant        and in Kennedy Creek, a very 'Small
                     over the past few years. About 50,000            tributary in the upper estuary at Wash-
                     acres of productive shellfish bottoms are        ington, NC, toxic metals may have been
                     currently closed on temporary or perma-          enriched by up to ten times the pre-man
                     nent basis. Often, after heavy rainfall,         concentrations. One factor not considered
                     additional acreage is closed for several         by the report's authors is the effect of
                     days to several weeks. Albemarle Sound is        sediment composition on metals concentra-
                     not a contributor to commercial shellfish,       tions. The percent organic matter and the
                     but Pamlico Sound has oysters, clams, and        sand-clay ratio are known to affect the
                     bay scallops in several areas. Most of the       affinity of estuarine sediments exposed to
                     closure is to the south of the Pamlico Sound     (otherwise) equal loadings ofmetals (White

                            Major Environmenfal Concerns                                                                        2 1

                            A al. 1985). Riggs et al. (1989) did present
                            data indicating that both of these factors
                            varied considerably among their sampling
                            locations, but their metals data apparently
                            were not normalized with regard to these
                            differences (J. Bray, personal communica-
                            tion). The Pamlico concentrations data,
                            taken as a whole, appear to be typical of
                            estuaries that are considered to be relatively
                            unpolluted with the metals.

                            Table 2.1.      Heavy metal concentrations (Ag1g) in the most and leastpollutedportions of the
                                            PamlicoRiver. "Pamlico average"is the trimmed mean for the whole system (i.e.,
                                            all values more than 2 standard deviations from the mean were eliminated).
                                            Kennedy Creek is the most polluted and Chocowinity Bay is the least polluted
                                            portion of the system (from Riggs et al. 1989).

                            Metal            Pamlico              Kennedy Creek                           Chocowinity Bay
                                             Average       Average         Min        Max           Average       Min         Max

                            Arsenic            12.80        21.20          5.80       35.40         7.80          3.60        12.60
                            Cadmium              0.36         0.85         0.30         1.70        0.18          0.00         0.40
                            Chromium           10.50        27.30          5.90       58.80         4.60          2.50         8.30
                            Copper             13.60        51.50         17.60       84.40         6.40          3.50         9.80
                            Nickel               2.70         8.40         1.50       13.30         1.00          0.10         2.10
                            Lead               35.90        68.50         29.80       86.90         21.70        11.90        40.90
                            Zinc               77.00        377.90       151.20       490.30        35.60        17.10        56.60
                            Mercury              0.09         0.44         0.16         1.30        0.06          0.03         0.08

                         CHAPTER3
                         Trends in Nutrient Production: An
                         Estimate Based on Changing Land
                         Use and Population

                             Of the wide variety of chemicals                 The ultimate question is: Even if stringent
                         discharged into estuaries, two plant growth          point and nonpoint source nutrient controls
                         nutrients, nitrogen (N) and phosporus (P),           are adopted, can [estuaries] survive in a
                         have been identified again and again as              desirable natural state in the face of
                         among the most critical, with the potential          continuing increases in nutrient sources
                         for widespread impact on estuarine re-               resulting from population growth and
                         sources. Frequently, increases in popula-            changing land use? Only time will tell.
                         tion density, fertilizer use and conversion          C.F. D'Elia (1987)
                         of forest land to agriculture are cited as the
                         causes for increased nutrients leading to         3) the amount contained in the manure of
                         eutrophication in estuaries (e.g., Macknis        farm animals. Loading, on the other hand,
                         1985; North Carolina DNRCD 1987).                 refers to the quantities of nutrient actually
                             While it is intuitively obvious that in-      reaching the estuary. There is a difference
                         creased estuarine nutrient loading ought          between the two because ofprocess ingthat
                         to occur as the basin population grows,           occurs as nutrients are transported from
                         usually there are little or no historical data    the sources toward the estuary. The produc-
                         to clearly show the quantitative relation-        tion rate normally exceeds the loading
                         ships between the anthropogenic changes           rate, because there are losses along the
                         and changes in nutrient loading. Scores of        way, due to such processes as sedimentation
                         current N and P loading estimates have            (for P) and denitrification (for N).
                         been made for various estuarine drainage             The reader should keep in mind that
                         basins, including the Neuse, Chowan, and          the estimates made in this study are for
                         Tar-Pamlico River estuaries in NorthCaro-         production, not loading. Loading from the
                         lina (see Chapter 1), but studies ofhistorical    basin can be measured directly by multiply-
                         trends in nutrient loadinghave rarelybeen         ing stream discharges times nutrient con-
                         made. The objective of this study was to          centrations. The data for the computations
                         use historical population and agriculture         normally come from monitoring flows and
                         statistics for estimating trends in annual        concentrations at the head of the estuary.
                         N and P production within each of the             The advantage of this method is obvious; it
                         major Albemarle-Pamlico sub-basins.               gives a direct measure of the actual quantity
                             Actually, there is probably a large differ-   of nutrient discharged from the watershed.
                         ence between nutrientproduction within a          However, the technique could not be used
                         watershed and loading to an estuary. For          in this study because of a lack of long-term
                         purposes ofthis study, nutrientproduction         monitoring of N and P concentrations at
                         refers to the sum of 1) the nutrients dis-        the mouths of the streams and rivers empty-
                         charged from point sources, 2) that esti-         inginto the estuaries in North Carolina. In
                         mated to come from each non-point source          fact, there are very few estuaries for which
                         (e.g. field, forest, or the atmosphere), and

                      24                                                                               Chapter 3

                      such a data set is available. Another           cropland, 3) other non-forested farmland
                      disadvantage is that this method gives no       (mostly idle cropland), 4) forests, 5) pas-
                      indication of the sources of the nutrients.     tureland, 6) urban land, and 7) all other
                                                                      land areas. Point sources included munici-
                      Methods                                         pal wastewater treatment plant and indus-
                         Trends    in land use and nutrient           trial discharges. Atmospheric N depo-
                      production in theAlbemarle-Pamlico basin        sition was also included in the estimates.
                      were estimated for the period 1880 through          The primary sources for agricultural
                      1987 by summing computed estimates of           land use, crop and animal statistics were
                      annual point and nonpoint source produc-        the censuses conducted by the U.S. Bureau
                      tion for each county in the basin. The          of the Census and the North Carolina and
                      procedures were based on those of Thomas        Virginia Departments ofAgriculture. Num-
                      and Gilliam (1978), Craig and Kuenzler          bers of each type of farm animals, acreages
                      (1983), and Lowrance et al. (1985). For         and harvests of the major crop types, and
                      counties that are partly inside the basin,      acreages of the pastureland and "other
                      all data were weighted by the percentage        farm land" categories came from the census
                      of the county within the basin (Figure 3. 1,    reports (Table 3.2). Forest acreage statistics
                      Table 3. 1, Appendix 3. 1). Nonpoint sources    were compiled from U.S. Department of
                      considered included 1) eight categories of      Agriculture Forest Service Resource Bulle-
                      farm animals, 2) harvested agricultural         tins for North Carolina and Virginia (Table

                             40 53       3      8     1 11                 16     52  5
                              1     22      51     28       ...... 37 6          59                            N
                            47     30                        39            26       55   33 .67   68       69
                                   54                                                    23@-         14
                       58 56                10   49         61                   42
                                                                  63                 31
                                                                                                  46
                                                        24                                     1,
                                 27                                                          12.
                          20
                                                   17         21     41              4
                                                                           18
                                                                                           It' 64
                           KILOMETERS                                                              60
                                                        62                           38                    Is
                         0 20 40     60 80                           66
                                                                               "1 50     2
                                                            34           25                         32
                                                                     6S
                                                                         36        3
                                           ................
                                        . ...............
                                                                                         45
                                                                              3S
                                                                                               9

                      Figure 3.1. Map showing counties in each of the Albemarle-Pamlico 8ub-basins. The counties are
                      identified in Table 3. 1.

                           Trends in Nutrient Production                                                                       25

                           Table 3.1. North Carolina and Virginiacounties in   Table 3.2. Sources ofdataon agricultural landuse,
                           the Albemarle-Parnlico basin (numbers correspond    crop harvests, farm animals, fertilizer sales, forest
                           to those on map in Kgure 3. 1).                     and urban land areas, population, and municipal
                                                                               and industrial discharges.
                           Map             Map             Map
                           No. Name        No. Name        No.  Name           Agricultural Land Use, Crop Harvests and Farm
                                                                                    Animals Inventory
                           1. Appomattox   24. Granville   47.  Patrick          U.S. Bureau of the Census. 1880-1982. Primary source.
                           2. Beaufort     25. Greene      48   Perquimane       N.C. Department of Agriculture. 1923-1988. North
                           3. Bedford      26. Greeneville 49.  Person              CarolinaAgricultural statistics. Annual Bulletins and
                           4. Bertie       27. Guilford    60.  Pitt                Reports.
                           5. Botetourt    28. Halifax (VA) 61. Pittsylvania     Virginia DepartmentofAgricultur-e. 1920-1988. Virlinia
                           6. Brunswick    29. Halifax (NQ 62.  Prince George       Agriculture Statistics (Annual Reports).
                           7. Camden       30. Henry       53.  Roanoke
                           8. Campbell     31. Hertford    64.  Rockingham     Forest Data
                           9. Carteret     32. Hyde        65.  Southampton      Virginia
                           10.Caswell      33. Isle of Wight 66. Stokes          U.S. Forest Service (1943); Cruilmhank and Evans (1945);
                           11. Charlotte   34. Johnston    67.  Surry (VA)          Larson and Bryan (1959); Sheffield (1976, 1977a,
                           12.Chowan       35. Jones       68.  SurTy (NC)          1977b); Cost (1976); Brown (1985, 1986); Brown and
                           13. Craven      36. Lenoir      59.  Sussex              Craver (1985).
                           14. Currituck   37. Lunenburg   60.  Tyrrell          North Carolina
                           16. Dare        38. Martin      61.  Vance            U.S. Forest Service (1943); Cruikshank (1940);
                           16. Dinwiddie   39. Mecklenberg 62.  Wake                Cruikshank and Evans (1945); Larson (1957); Knight
                           17. Durham      40. Montgomery  63.  Warren              and McClure (1966); Welch and Knight (1974); Cost
                           18. Edgecombe   41. Nash        64.  Washington          (1974); Welch (1975); Bechtold (1985).
                           19. Floyd       42. Northampton 66.  Wayne
                           20. Forsyth     43. Nottoway    66.  Wilson         Fertilizer Sales
                           21. Franklin (NQ 44. Omnge      67.  Suffolk          Virgiiiia Department ofAgriculture. 1956-1988. Fertilizer
                           22. Fmnklin (VA) 46. Pamlico    68.  Chesapeake          used and results of inspection (annual reports).
                           23. Gates       46. Pasquotank  69.  Virginia Beach      Richmond.
                                                                                 U.S. Bureau of the Census. 1954, 1959, 1964. County
                                                                                    data on fertilizer materials applied to croplands.
                                                                                 Hargett and Berry (1985).
                                                                                 Mehring et al. (1985).
                                                                                 North Carolina Department of Agriculture. Various
                                                                                    dates between 1956 and 1988. Data for some years
                           Table 3.3. Coefficients used to compute nitrogen         contained in the N.C. agricultural statistics mports
                           and phosphorus production by five different land         issued annually.
                           use categories and by different types offarm animals.
                           Values for forest are from Loehr (1974), values for Population and Urban Land Areas
                           other land Uses are from Beaulac and Reckhow          U.S. Bureau of the Census. 1880-1983. Census of
                           (1980); values for animals are fi-om Barker (1987).      Population.
                                                                                 U.S. Bureau of the Census. 1949-1988. County and City
                           Land use category      Nitrogen      Phosphorus          Data Book.
                            or animal type        (kglyear)       ft/year)     Municipal and Industrial Discharges
                                                                                 N.C. Stream Sanitation Committee (1946, 1957, 1959,
                           Other Farmland         3.00/ha         0.40/ha           1961)..
                           Other Land             3.00/ha         0.40/ha        U.S. Public Health Service (1944, 1951, 1958, 1963).
                           Forest                 1.50/ha         0.20/ha        U.S. Environmental Protection Agency (1971).
                           Pastureland            4.00/ha         0.60/ha        Hall (1970).
                           Urban Land             6.00/ha         1. 10/ha       Vir%inia State Water Control Board (1976).
                                                                                 N.C. DivisionofEnvir-onmental Management (1986,1989)
                                                                                 Virginia State Water Control Board: NPDES Self-
                           Cattle                                                   Monitoring Data (1989).
                            Dairy              121.00/animal    22.00/animal     North Carolina Division ofErivironmental Management:
                            Beef               48.10/animal     13.10/animal        NPDES Self-Monitoring Data (1986-1989).
                           Swine               11.90/animal     4.20/animal      N.C. Board of Health. Various Dates. Annual reports.
                           Horses              46.40/animal     11.00/animal
                           Sheep                6.80/animal     1.50/animal
                           Poultry
                            Broilers            0.40/animal     0.10/animal
                            Layers              0.56/animal     0.20/animal
                            Turkeys             1.36/animal     0.52/animal

                           26                                                                                                        Chapter 3
                           3.2). Urban land areas were tallied from                       of non-forested, nonagricultural lands out-
                           U.S. Bureau of Census data (Table 3.2).                        side the boundaries of the towns and cities
                           Here "urban" areas are defined as the land                     (i.e., business properties, house lots, roads,
                           areas within the limits of towns and cities                    ponds, cleared power line right-of-ways,
                           with populations greater than 2,500. The                       etc.).
                           "other" land use categorv was calculated as                         Quantities of N and P released in the
                           the total basin land area minus the sum of                     excreta of farm animals were estimated by
                           all the other land use type acreages. This                     multiplying numbers of animals times co-
                           miscellaneous category consists primarily                      efficients (Table 3.3). Mass balance models

                                Table 3.4. Atmospheric deposition of (D) in kglhalyear and mean concentration (C) in @kgl I
                                of nitrogen andphosphorus at several locations within, or near, the AP watershed.

                                                                               N03-N               NH4-N              Total-P

                                Location                Year      Precip. (D)          (C)       (D)       (C)        (D)      (C)       Ref.
                                                                  (in.)

                                North Carolina          1975                5.54 (NO,+NH   4)    0.21                                      1

                                Duke Forest, NC         1972                1.46                 0.74                 0.28     21          2

                                Tar River
                                Swamp,NC                1976                                                          0.49     63          8

                                Rhode River             1974      108.6     3.91       360                            0.57     53          3
                                Watershed, MD           1975      142.4     4.65       327                            1.13     79          3
                                                        1976      115       5.57       484                            0.74     65          3

                                Creeping
                                Swamp,NC                1977                                                          0.70     64          7

                                Clinton, NC             1980      116.5     2.60       223       1.66      134        ...                  4
                                                        1981      113       2.37       210       1.66      138        ---                  4
                                                        1983      127.2     2.24       176       1.71      136        ---                  4

                                Lewiston, NC            1980       87.3     2.53       290       1.32      161        ---                  4
                                                        1981       79.5     1.69       213       1.01      127        ---                  4
                                                        1982      116.4     2.53       217       1.71      147        ---                  4
                                                        1983      106.1     2.75       262       0.00                                      4
                                                        1984      133.7     3.75       280       1.32      99         ---                  4
                                                        1986      117.6     1.96       167       1.24      153        ---                  4

                                Raleigh, NC             1980       94.1     2.39       254       1.79      190        ---                  4
                                                        1981       81.3     1.56       192       1.24      163        ---                  4
                                                        1982      114.7     2.48       217       2.10      183        ---                  4
                                                        1983      126.7     2.64       209       0.00                                      4
                                                        1984      123.9     2.30       186       1.84      149                             4
                                                        1985       93.3     1.76       189       1.61      173        ---                  4

                                Greenville, NC          1968      119       8.00       672       1.30      109                             5

                                Roanoke, VA             1958      127       8.90       701       2.40      189                             5

                                Cape Hatteras, NC       1958      137       3.20       234       1.20      88                              6

                                1. Wells and Jorgensen 1975; 2. Wells et al. 1972; 3. Miklas et al. 1977; 4. Olsen and Watson 1986; Olsen and
                                Slavich 1986; 5. Junge 1958; 6. Galloway et al. 1984; 7. Kuenzler et al. 1980; 8. Holmes 1977.

                                Trends In Nutrient Production                                                                                           27

                                for N and P were calculated for agricultural                        The amount of fertilizer applied
                                cropland, following the methods of Craig                       annually to cropland was assumed to be
                                and Kuenzler (1983) and Lowrance et al.                        equal to the amounts sold in, or shipped to,
                                (1985). The annual cropland nutrient bud-                      the counties. Historical data on fertilizer
                                gets for each AP sub-basin were estimated                      sales were taken from a number of sources
                                by:                                                            (Table 3.2). Actually, most of the data are
                                     (Precipitation + Fertilizer + Symbiotic N-Fixation) -     reported as tons of "mixed fertilizer" and
                                          (Harvest + Denitrification) = N Balance; and         "fertilizer materials" either received in the
                                   (Precipitation + Fertilizer) - (Harvest) = P Balance.       counties from manufacturers for retailers
                                     The "balances" when positive, were                        and consumers (North Carolina), orsold by
                                                                                               each county (Virginia). To convert tons of
                                assumed to represent the maximum "crop-                        mixed fertilizer and fertilizer materials
                                land pollution potential"; i.e., the quantity                  into tons of elemental N and P, I multiplied
                                of nutrient that could leave the watershed                     by the percentages of N and P in each type
                                through surface or subsurface flow. Of                         of material sold. The N fixation rate used
                                course, this assumes that nutrient storage                     for soybeans was 105 kg/ha per year (93.5
                                in the soil system is not changing (Frissel                    lb/acre per year) (Frissel 1978), and for
                                1978).                                                         peanuts the rate was assumed to be 112
                                     Wet precipitation inputs for each year                    kg1ha per year (99.7 lb/acre peryear) (Craig
                                were calculated by multiplying the total                       and Kuenzler 1983). The amounts of N
                                annual precipitation (average of several                       and P harvested were determined by multi-
                                sites within the Albemarle-Pamlico (AP)                        plying the nutrient content by the annual
                                basin, times the estimated N and P concen-                     yields (e.g., bushels/acre) ofthe majorcrops
                                trations, times land areas. N and P concen-                    (Gilbertson et al. 1978; Romaine 1965)
                                trations in precipitation for the mid-1980s                    (Table 3.5). Finally, denitrification rates
                                were based on measurements from                                were assumed to be 15% of the applied
                                National Atmospheric Deposition Program                        fertilizer N (Porter 1975; Thomas and
                                stations in the AP basin, and on other
                                recent measurements (Table 3.4); but his-
                                torical Nconcentrations had to be calculated
                                indirectly. This was done by assuming                          Table 3.5. Nitrogen and phosphorus content in
                                that N deposition in 1880 was 20% of the                       harvested crop materials (Gilbertson et al. 1978,
                                rate today, and that the rate of change                        Romaine 1965).
                                since 1880 has been exponential. These                                                Harvest    Pounds/Harvest Unit
                                assumptions are, in turn, based on mea-                        Crop                   Unit       Nitrogen Phosphorus
                                sured (present-day) atmospheric N deposi-
                                tion rates in remote areas (Table 3.4) and                     Com (gmin)             Bushel       0.900         0.153
                                                                                               Com (silage)           Ton          4.0           0.45
                                on estimated historical trends in N oxide                      Oats (grain)           Bushel       0.625         0.113
                                production in the southeastern U.S. (see                       Wheat (grain)          Bushel       1.250         0.275
                                Discussion). The total atmospheric N                           Hay
                                                                                                  Alfalfa             Ton        45.000          4.500
                                deposition was twice the wet precipitation                        Bluegrass           Ton        30.000          4.600
                                loading, based on the assumption that dry                         Coastal Bermuda     Ton        23.125          3.876
                                                                                                  Cowpea              Ton        60.000          5.500
                                deposition equals wet deposition (see                             Peanut              Ton        46.667          4.889
                                Discussion). No information on historical                         Red Clover          Ton        40.000          4.400
                                trends in atmospheric P production or                             Soybean             Ton        45.000          4.600
                                                                                                  Timothy             Ton        24.000          4.400
                                deposition were available; therefore, a con-                   Cotton                 Pound        0.018         0.002
                                stant rate of deposition (0.5 kg/ha/yr) was                    Peanuts (nuts)         Pounds       0.036         0.002
                                assumed, based on measurements in the                          Soybeans (grain)       Bushels      3.750         0.375
                                AP region (Table 3.4).                                         Tobacco (leaves)       Pounds       0.038         0.004

                            28                                                                                                          Chapter 3

                            Gilliam 1978).                                                   discharges within eachAP sub-basin (>O.l
                                 Nutrient production was not calculated                      mgd), as well as information on N and P
                            by this mass balance approach for any land                       concentrations in the industrial discharges.
                            use category other than harvested cropland.                      The most difficult parameters to estimate
                            Instead, export coefficients (kg N and P per                     were the treatment factors that would be
                            ha per year) were multiplied times total                         applied to each discharge. Fortunately,
                            sub-basin acreages to give the "expected"                        there were periodic inventories ofmunicipal
                            nutrient yields from pastureland, forests,                       wastewater facilities from 1942 through
                            urban, other farm lands, and "other"areas.                       1985 (Table 3.2) which included detailed
                            N and P "yield" coefficients foreach of these                    information on the levels of treatment pro-
                            land-use categories were taken from the                          vided by each facility and the size of the
                            literature (Table 3.3).                                          "sewered" population. Another valuable
                                 Both municipal and industrial dis-                          source was the N.C. Department of Health
                            charges     *were included in the point-source                   annual reports, which yielded information
                            nutrient production estimates. For indus-                        on the early history of municipal waste-
                            trial sources the annual production was                          water treatment in North Carolina. For
                            calculated by multiplying daily discharge                        years before 1942, the sewered population
                            times thetotal NorP effluent concentration                       was assumed to be equal to the city
                            times 365. Municipal production was                              population (U.S. Census Bureau data), back
                            computed as                                                      to the time when the sewage collection
                                                                                             system for the town was first constructed.
                            kg N or P/year                                                        The per capita annual N and P produc-
                            Sewered * Per capita                Treatment * 365              tion was taken as 4.6 kg N and 1.2 kg P
                            population       daily N or P factor                             (Gakstatter et al. 1978), and the N treat-
                                             production                                      ment factors ranged from 1 (untreated) to
                                                                                             0.47 (secondary treatment), depending on
                            where sewered population is the estimated                        the type of wastewater treatment practiced
                            number of persons served by the citys                            by the municipal treatment plant. P treat-
                            wastewater collection system. Information                        ment factors ranged from 1.0 to 0.74 (Table
                            on industrial and municipal discharges                           3.6)_
                            was gleaned from several sources. The                                 From 1880 through 1920 the nutrient
                            NPDES Compliance Monitoring data files                           production estimates were computed at
                            were searched to provide lists of all current                    10-year intervals, correspondingto the U.S.
                                                                                             Agricultural census dates. After 1920,
                                                                                             more frequent agriculture census data were
                            Table 3.6. Per capita total nitrogen and total                   available so that I was able to make
                            phosphorus loads (kglyear) in wastewater effluents               calculations at 4-to-5 year intervals. Many
                            as a function of treatment type (Gakstatter et al.               of the data were first compiled in the
                            1978). -Treatment factors are equal to the load for a            English units of measure (acres of land,
                            given treatment type divided by the load for no                  pounds of crop harvest, tons of fertilizer
                            treatment.                                                       sold, square miles of county land area, etc.)
                                                     Nitrogen           Phosphorus           in which they were originally recorded
                            Treatment type       kg/year Factor kg/year Factor               (e.g., Appendix 3.3). But at some stage in
                            None                     4.6      1.00        1.2     1.00       the procedure, all these values were
                            Primary                  4.2      0.90        1.1     0.90       converted to metric units, and the summed
                            Secondary
                               Trickling filter      2.9      0.62        1.0     0.82       nutrient production rates are expressed as
                               Activated sludge      2.2      0.47        1.0     0.82       kg(ha/year, or metric tons per year.
                               Stabilization pond    1.9      0.42        0.9     0.74            Results are presented for the whole

                        Trends in Nutrient Production                                                                29

                        Albemarle-Pamlico watershed, as well as           Pastured land increased from about 0.8
                        for each of the major sub-basins: Chowan          million acres (0.32 million ha) in 1925 to a
                        River, Roanoke River, Tar-Pamlico River,          peak of 1.1 million acres (0.44 million ha)
                        Neuse River, and "Coastal". The Coastal           in the mid-1950s, and has since declined to
                        sub-basin includes all land area down-            around 0.85 million acres (0.34 million ha).
                        stream from the mouths of the river estu-         In addition to the 1.1 million acre decline in
                        aries, primarily parts of Camden, Curri-          harvested cropland since 1925, there must
                        tuck, Dare, Hyde, Pamlico, Pasquotank,            have been about 2 million acres of other
                        Perquimans, Tyrrell and Washington                land in farms "lost" duringthat time period,
                        Counties in North Carolina (Figure 3.1,           since the total "acres in farms"has declined
                        Appendix 3.1). In some of the figures and         from 11 million to around 8 million (4.45
                        tables (especially Appendix tables), the          million to 3.2 million ha) (Figure 3.3a).
                        "Coastal" sub-basin is further sub-divided        Finally, urban land areas (defined here as
                        into the "Albemarle" and "Pamlico" sub-           land in towns and cities >2,500 population)
                        basins, in reference to the sound into which      increased rapidly beginning about 1930,
                        the land drains.                                  and today amounts to around 0.3 million
                                                                          acres (0.12 million ha), or about 2% of the
                        Results                                           total AP basin land area.
                        Land Use                                             There are not good data on any of the
                            There have been relatively small              major land use categories, except harvested
                        changes in the amounts of land in each of         cropland, before 1930, so that the 1880-
                        the major land-use categories in the              1925 values used in the nutrient production
                        Albemarle-Pamlico basin use during the            calculations are only estimates, but prob-
                        past century (Figures 3.2 and 3.3, Appendix       ably are not far off. Judging from the
                        3.2). Forest has always been the most             number of cattle on farms, the known
                        prevalent land use in the basin, ranging          cropland acreages, and the total land in
                        between 57.6% and 63.7% of the total              farms values, and assuming that urban
                        basin land area. There was a peak in forest       land use was much less than 1% before
                        acreage in the 1960s. Harvested cropland,         1930, the forested areas must have been
                        the second most prevalent land use, peaked        about the same in the late 1800s as in
                        at 3.55 million acres (1.4 million ha) in         1925. That is the assumption I have made
                        1940 and has generally declined since, to         for purposes of the nutrient production
                        2.43 million (1.0 million ha) in 1987.            calculations. Actually, the errors in this
                                                                          assumption are probably much less impor-

                        Figure 3.2. Percentages of land use by six 7-
                        major categories for the Albemarle-Pamlico to     M  Urban
                                                                   a
                        estuarine system drainage area, 1925-1982. M      =  01ther
                                                                      75%-=  Other Farmland
                                                                   Is
                                                                   S         Pasture
                                                                   0         crops
                                                                   CO  50%_
                                                                   0      M  Forest

                                                                   CL
                                                                      25%-

                                                                   E      A

                                                                      0%
                                                                          80 90  0   10  20 25 30 35 40 45 50 54 50 64 69 74 78 52 87
                                                                                         Year (1880-1987)

                            30                                                                                              Chapter 3

                                                                                                             Figure 3.3. Historical
                                            Chowan             Roanoke             Tar          A            trends in land areas (land in
                                                                                                             farms, harvested cropland,
                            0-15            Neuse              Coastal                                       Pasture-land, forest, and
                            C                                                                                urban) by sub-basin in the
                            .2
                                                                                                             Albemarle-Pamlico
                                                                                                             drainage basin.
                            E   9-
                            cd
                            LL
                            .G  6

                                3-

                                0
                                  80     90   0     10    20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                          Year (1880-1987)

                                4000
                                                                                                 B
                                            Coastal

                            0               Neuse
                                3000-       Ter

                                            Roanoke

                                            Chowan
                                2000

                            CI
                            e
                            0   1000-

                                  0
                                     80     90  0     10    20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                            Year (1880-1987)

                                1200
                                                                                                  C
                                            Coastal
                                "00   M N.use

                            0               Tar
                                800-
                                            Roanoke

                                            Chowan
                                600-

                                400-

                                200-
                            Cd
                            CL
                                     80     90   0    10    20 25 3@ 315 410 415 510 514 519 614 619 714 78 82 87
                                                            Year (1880-1987)

                                  Trends in Nutrient Production                                                                                                      31

                                  Figure 3.3. continued                             12 -                                                                           D
                                                                                             Coastal
                                                                                    lo-      Neuse

                                                                                             Tar
                                                                             .2     8-
                                                                                             Roanoke

                                                                                             Chowan
                                                                             0)     6-

                                                                                    4

                                                                             0
                                                                             LL     2-

                                                                                    0.. . . . .
                                                                                      80     90         0  10     20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                                                                                  Year (1880-1987)

                                                                                    350 -
                                                                                                                                                                   E
                                                                                               Coastal
                                                                                    300 -
                                                                                               Neuse

                                                                                    250 -      Tar

                                                                                               Roanoke
                                                                             0
                                                                             M      200 -      Chowar.

                                                                             U)     ISO-
                                                                             0)

                                                                                    100-

                                                                                    50-

                                                                                    0-
                                                                                       80               0   10     20 25 30 35 40 45 50 64 59 64 69 74 78 82 87
                                                                                                                   Year (1880- 1987)

                                  tant than those in choosing the export                                planted in significant acreages in the 1930s
                                  coefficients (see Discussion).                                        and 1940s, but up until about 1960 never
                                        Some crops are much more important                              made up more than 5-10% of the total.
                                  in the AP basin now than in the past, while                           However, by 1987 there were 0.85 million
                                  others have become relatively unimportant                             acres (0.34 million ha) of soybeans, which
                                  over the years (Figure 3.4, Appendix 3.3).                            was about one-third of the total harvested
                                  In terms of acres harvested, corn has been                            cropland.
                                  dominant throughout the past century,                                      In contrast, tobacco and, especially cot-
                                  accounting for between 0.8 million acres                              ton, acreages have declined in the
                                  and 1.5 million acres (0.32-0.61 million                              Albemarle-Pamlico basin (Figure 3.4).
                                  ha), or, on average, about 35% of the total                           Annual tobacco plantings peaked in the
                                  harvested cropland. The second most wide-                             1930s and 1940s at around 0.6 million
                                  ly planted crop today, soybeans, was first                            acres (0.24 million ha), but now are down

                          32                                                                                                    Chapter 3

                               1000-                                                                            Figure 3.4. Historical trends
                                                                                                     A          in amount offarm land used
                                                                                           Coastal
                                                                                                                for six major crops, by sub-
                            r_ 800-                                                        Nauss                basin, in the Albemarle-
                            cc
                            cc                                                                                  Pamlico basin, 1880-1987.
                            M                                                              Tar
                            0
                                                                                           Roanoke
                               600-
                            4)                                                             Chowan
                            CD

                               400-

                            C
                            0  200-
                            0

                                  0-
                                     80   90     0    10    20 25 30 35 40 45    54 59 64 69 74 78 82 87
                                                            Year (1880-1987)

                               2000-
                                                                                                     B
                          0    1800-         Chowan              Roanoke              Tar

                          cc   1600-         Neuse               Coastal
                          cc
                          :3
                          0    1400-

                               1200-

                               1000-
                          <    800-

                          0    600-

                               400-
                          cc
                               200-

                                  0-
                                     80   90    0     10    20 25 30 35 40 45 50 54 59   @9 ;4 ;8     8`7
                                                            Year (1880-1987)

                               800-
                                                                                                     D
                               700-       Coastal

                                          Neuse
                          (A
                               600-
                                          Tar
                          cc
                          w
                          =    500-       Roanoke
                          0
                                          Chowan
                               400-

                               300-

                          >%   200-
                          to
                          X                                                             NMI
                               too-      I          !
                               O_q
                                         90          0    20 25 30 35 40 45 50 64 5
                                  so           0    1                               9 64 69 74 78 82 87
                                                           Year (1880-1987)

                              Trends In Nutrient Production                                                                                       33

                              Figure 3.4. continued                        400-

                                                                                        Coastal

                                                                                        Neuse
                                                                       to  300-         Tar
                                                                       0
                                                                                        Roanoke
                                                                       t                Chowan
                                                                           200-
                                                                       .PC

                                                                           too-

                                                                            0-
                                                                                80      90  0     10    20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                                                                        Year (1880-1987)

                                                                           1200-
                                                                                                                                                 G
                                                                                        Coastal
                                                                       'Oa 'ODO
                                                                       Cd
                                                                                        Tar
                                                                       0    800-
                                                                                        Roanoke

                                                                                        Chowan
                                                                            GDO -

                                                                       r-   400-

                                                                       .0
                                                                            200-

                                                                                0 --F   I---- I ---
                                                                                 80     90   0     10    20 26 30 36 40 45 50 54 59 64 69 74 78 82 87
                                                                                                         Year (1880-1987)

                                                                           700-

                                                                                  =     Coastal
                                                                           6w -
                                                                                        Neuse

                                                                       CIS 500-         Tar
                                                                       0)
                                                                       :3
                                                                       0                Roanoke
                                                                           400-         Chowan

                                                                           300-

                                                                       0   200-

                                                                       J2  100-
                                                                       10-

                                                                                so      90  0     10    20 25 30 354 0 45 @O 64 @9 @4 @9    78 82 87
                                                                                                        Year (1880-1987)

                       34                                                                                      Chapter 3

                       to around 0.2 million acres (0.08 million           million acres orO.12 million ha) but declined
                       ha), or approximately 7% of total cropland          rapidly, then rose slightly in the 1950s,
                       acreage. Cotton production in the basin             and have since fallen back to become
                       was very important up until the 1930s, but          insignificant in recent times in comparison
                       then it declined rapidly and had practically        to other crops. Peanut production in the
                       ceased by about 1970. At its peak in the            AP basin increased rapidly in the early
                       1920s, cotton was the second most widely            part of this century, and in terms of acres
                       planted crop, taking up as much as 35% of           grown, peaked around 1945 at 0.35 million
                       the total cropland in some years. Wheat             acres (0.14 million ha). Since 1954, the
                       and other small grains have never been              peanut acreage has remained nearly con-
                       dominant crops in this area. In 1987 only           stant at about 0.23 million (0.09 million
                       about 12% ofAP basin cropland (0.3 million          ha). Finally, hay crops are a relatively
                       acres or 0.12 million ha) was devoted to            minor part of the total cropland use today
                       wheat, and this was the second highest              (<10% of total). This crop was somewhat
                       acreage planted in wheat, at least during a         more important in the past, but was never
                       census year, over the past 100 years. Oats          dominant. The largest hay acreages were
                       were widely grown in the late 1800s, (0.3           in the 1940s, when they peaked at around

                          160-
                                                                               A
                          140- = Coastal                                                      Figure 3.5. Trends in nitrogen
                       Cd                                                                     and phosphorus sold as
                       0
                               M Nauss                                                        commercial fertilizer, by sub-
                       =0          Tar
                                                                                              basin, in theAlbemarle-Parnlico
                          loo-     Roanoke                                                    drainage basin, 1880-1987.
                               M Chowan
                          80-
                       t

                          Go-

                          40-
                       0

                       Z  20-
                       a,
                       C   0 -
                       9      80   @O      1@   20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                Year (1880-1987)

                       M  50-
                       V
                                                                               B
                                   Coastal

                       0  4o-      Nauss

                                   Tar

                                   Roanoke
                          30-
                              M Chowan

                       LL
                          20-

                       0
                       CL to-
                       OD
                       0
                          0_@Al
                       12     80  90  0   10   20 25 @0 35 40 45 50 54 69 64 69 74 78 82 87
                                               Year (1880-1987)

                               Trends In Nutrient Production                                                                                                  35

                               0.7 million acres (0.28 million ha).                               increased about 7-fold between 1940 and
                                                                                                  1978, when a peak of 140,000 tons N (127.6
                               Harvested Cropland Nuffient Mass                                   million kg N) was reached. N fertilizer
                               Balance                                                            sales, like P sales, have declined slightly in
                                    Since about 1900, the major nutrient                          the 1980s, but some of the apparent decline
                               inputs to croplands have been N and P                              may be attributable to low demand (i.e.,
                               fertilizer. Large increases in the use of                          poor weather) during the census years,
                               fertilizers have occurred in the AP basin                          rather than to a long-term downward trend.
                               over the past 50 years (Figure 3.5, Appendix                       That was certainly the case in 1987, when
                               3.4). Annual P sales peaked in the 1960s                           acres planted, fertilizer use, and harvest
                               at around 45,000 tons P (40.9 million kgp),                        were all lower than normal due to drought
                               but have declined to 25,000-30,000 tons P                          conditions in much of the region.
                               (22.7-27.3 million kgP) in the 1980s (Figure                            The other variable nutrient input on
                               3.5b). Meanwhile, however, there has                               the cropland has been atmospheric deposi-
                               been a very rapid rise in the amount of N                          tion. As will be discussed below, there
                               fertilizer sold. In fact, annual sales                             probably has been about a five-fold increase
                                                                                                  in the areal rate ofatmospheric N deposition

                               Figure 3.6. Trends in yield (pounds                        120-                                                                A
                               and bu8hels per acre) for 8even major
                               crop8 in theAlbemarle-Pamlico basin,                       too-
                               1880-1987.
                                                                                                                                                    Com
                                                                                          80-

                                                                                                                                                      oats
                                                                                          Go -

                                                                                                                                                        Wheat
                                                                                     V    40-

                                                                                          20-                                                          Soybeans

                                                                                          0__
                                                                                               80 90    0     10    20 25 30 35 40 45 @O @4 5@ @4 6@ 74 78 82 87
                                                                                                                     Year (1880-1987)
                                                                                          35M -
                                                                                                                                                              B
                                                                                          3000 -                                                 PeanLft

                                                                                          2500-

                                                                                          2000-

                                                                                     0                                                              Tobacco
                                                                                     S    1500-
                                                                                                                                                        Wheat

                                                                                                                                                       Soybeans

                                                                                                                                               4Nanul
                                                                                                                                                    Tobacco

                                                                                     .LD  1000-
                                                                                                                                                         Coldon

                                                                                          500

                                                                                               0
                                                                                               80  90    0     10    20 26 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                                                                                     Year (1880-1987)

                                    36                                                                                                                Chapter 3

                                    TableS.7. Croplands N and P mass balance, on a per hectare basis, for selected years.

                                    Input/Output        1880              1900             1920            1940              1959             1974              1987

                                    (kg N/ha)
                                    N fertilizer        0.84              5.07             17.40           16.34             41.25         111.04             96.70
                                    Harvest             -8.77          -12.78              -19.42         -29.73             -47.71        -80.41             -83.99
                                    N fixation          0.00              6.26             9.01            17.31             19.79          36.17             46.02
                                    Denitrification     -0.12             -0.76            -2.61           -2.45             -6.18         -16.65             -14.50
                                    Precipitation       0.80              0.80             1.10            2.25              3.32              3.93             4.32
                                    Balance             -7.25             -1.40            5.48            3.71              10.47          54.08             48.54

                                    (kg P/ha)
                                    Fertilizer          1.69              8.45             22.41           16.70             32.68          36.05             24.96
                                    Precipitation       0.27              0.29             0.31            0.36              0.55              0.54             0.59
                                    Harvest             -1.48             -1.94            -2.70           -2.70             -6.03         -10.17             -10.24
                                    Balance             0.48              6.81             20.02           14.36             27.19          26.42             15.30

                                    250-                                                                                     in the AP basin over the past
                                                   Fort                Nft                 Precip                            century.          However, the
                                    2W -           Harv                Dent                Balance                           atmospheric N input to crop-
                                    iso-                                                                                     lands today is still very small
                                    'a 11)0-                                                                                 in comparison to fertilizer N
                                    r_      Inputs
                                    0                                                                                        and N fixation.
                                    50-
                                                                                                                                With increasing fertilizer
                                      0                          soon                                                        and pesticides use, and more
                                    -510    Outputs                                                                          productive crop varieties, in-
                                    -iou -                                                                                   creases in yields (bushels or
                                    _150-                                                                                    pounds per acre) for some
                                            8@ 9`0      0   10   20    30     40   5@ @9             78    87                crops      has         been          very
                                                                  Year (1880-1987)                                           impressive (Figure 3.6,
                                                                                                                             Appendices 3.5, 3.6). The
                                    so-                                                                                      greatestyield increases came
                                              Balance                                                                        between about 1940 and the
                                              Harv                                                                           1970s. For example, corn
                                    3o-       Precip                                                                         yield increased about 5-fold,
                                              Fart                                                                           from around 20 bushels/acre
                                    r- 20-
                                    0                                                                                        to over 100 bushels/acre.
                                            Inputs
                                    @i 10-                                                                                   Wheat yields improved about
                                    22                                                                                       4-fold, oats by a factor ofabout
                                             001 M                                                                           2.5, and soybean yield
                                    -10-    Outputs                                                                          approximately doubled over
                                    -2U -                                                                                    the past 40 years or so. There
                                                     0   10    20      30    40   50       59 _T_  69 78   87                ave       been         impressive
                                                                 Yew (1880-1987)                                             increases in the tobacco and
                                                                                                                             peanut yields also (Figure
                                    Figure 3.7. Historical trends in croplandnitrogen andphosphorus                          3.6).
                                    mass balances in the Albemarle-Pamlico basin, 1880-1987.                                    Cropland nutrient mass
                                                                                                                             balances for all of the AP basin

                                Trends in Nutrient Production                                                                                                 37

                                Figure 3.8. Historial trends in                  16DO -
                                numbers ofeightmajorcategories                                                                                              A
                                of farm animals, by sub-basin,                   1400-     M Chowan              ME Roanoke                  Tar
                                in theAlbemarle-Pamlico basin,                                   NeuSe                 coastal
                                1880-1987.                                       1200-

                                                                                 10DO -

                                                                             0    800-

                                                                                  6w -
                                                                             S
                                                                             @:   400-

                                                                                  200

                                                                                       so     90     0     10    20 253  03 5 40 4550   64 59 64 69 74 ; 8 @2 87
                                                                                                                 Year (1880-1987)

                                                                                 600-

                                                                                                Chowan                Roanoke               Tar
                                                                                 5M             Neuse                 Coastal

                                                                                 400-

                                                                                 300-
                                                                             0

                                                                                 200-

                                                                                 100

                                                                                   0
                                                                                       80     90    0     10     20 25 30 35 40 45 50 64 59 64 69 74 78 82 87
                                                                                                                 Year (1880-1987)

                                                                                 200-

                                                                                              Coastal

                                                                                              Neuse
                                                                                 ISO-         Tar

                                                                                              Roanoke

                                                                                              Chowan
                                                                             0   loo-

                                                                             to
                                                                             4)        11111111111111                                                      '11
                                                                                                                                            Tar

                                                                                  50 -

                                                                                   0
                                                                                       80     90    0     10     20 25 30 35 40 45 50 54 59 64 69 74 78 82 87
                                                                                                                 Year (1880-1987)

                         38                                                                                             Chapter 3

                            140-                                                             D               Figure 3.8. continued
                                                                                    Coastal
                            120-
                                                                                    Neuse

                         V
                            too-                                                    Tar
                         C
                                                                                    Roanoke
                            So-                                                     Chowan
                         o

                            60-

                            40-
                         0

                            20

                              0-
                                 so    90   0    10    20 26 30 35 40 45 50 64 69 64 69 74 78 82 87
                                                       Year (1880-1987)

                            180-

                            ISO-                                                    Coastal
                            140-                                                    Neuse
                                                                                    Tar
                            120-                                                    Roanoke

                            100-                                                    Chowan

                            80-

                            60-

                            40

                            20-

                              0-
                                 80    90   0    10    20 25 30 35 40 45 50 64 59 @4 @9 74 78 82 87
                                                       Year (1880-1987)

                            20-
                                                                                           F
                                        Chowan             Roanoke             Tar

                                        Neuse              Coastal

                         .2

                            to-

                            0-1
                                 so 90     0    10    20 26 30 35 40 45 So 54 59 64 69 74 78 82 87
                                                      Year (1880-1987)

                    Trends In Nutrient Production                                              39

                                                 20-
                    Figure 3.8. continued            M Chowan        Roanoke       Tar      G
                                                     M Nauss         Coastal
                                                 16-

                                              0

                                                 to-

                                              0
                                              L.
                                              CO  6-

                                                  0-
                                                   so 90    0 10  20 25 30 36 40 45 50 54 59 64 69 74 78 82 87
                                                                  Year (1880-1987)

                                                 2500-
                                                                                             H
                                                         coastal

                                                20DO -   Nauss

                                                         Tar

                                                         Roanoke
                                                 1500-
                                                         Chowan
                                              0

                                                  500

                                                   0
                                                     so  90 0   10 20 25 30 35 40 45 50 54 59 S4 69 74 78 82 87
                                                                   Year (1880-1987)

                    are shown in Figure 3.7. The N "balance", about the same as that described above for
                    which represents the difference between the whole AP basin; what differences there
                    inputs and outputs, has increased gradually are due simply to differences in the amount
                    from near zero, or less than zero, in the late of harvested cropland. There was a rapid
                    1800s, to around 50 million kg N per year increase in the 1950-1970 period, with a
                    by 1964, but appears to not have changed leveling off since then (Table 3.7). Excess
                    greatly since then. The P "balance", on the cropland P also followed about the same
                    other hand, increased most rapidly in the pattern described above forthe whole basin,
                    early 1900s, reaching a peak of about 36 and the per hectare values have ranged
                    million kg P in the 1950s. Since, then, the from 0.5 kg in 1880 to as high as 31.3 kg in
                    P balance has declined to about 20 million 1969. In recent years the excess P has been
                    kg P, or about the same amount as in the around 15 kg/ha.
                    period 1910-1940.
                       The annual excess cropland N has
                    ranged from -7.2 kg/ha in the late 1880 to
                    as high as 54.1 kg/ha in 1974. The trend is

                        40                                                                                           Chapter 3

                                                                                of increase, so that now there are more
                        Farm AnImal Inventories and                             than ever (1.4 million) of these animals.
                        Nutrient Production                                     The increases in swine since 1959 have
                             In every census since 1880, swine have             taken place in the Tar, Neuse, and Coastal
                        been the most numerous large farm animal                sub-basins, while inventories in the
                        in the Albemarle-Pamlico basin (Figure                  Roanoke and Chowan basins have fallen
                        3.8, Appendix 3.7). Between 1880 and                    slightly. Swine production is concentrated
                        1940, the swine inventory fluctuated be-                in the central coastal plain in North Caro-
                        tween 500,000 and 850,000 head, but after               lina; thus the Tar River Basin has 23% of
                        1945 it rose steadily, and by 1959 there                all the hogs in the AP system, and 38% are
                        were over 1 million head. A decline in the              in the Neuse River basin.
                        early 1960s was followed by another period                  Cattle, on the other hand, have always
                                                                                been most numerous in the northwestern

                            80-
                                                                                                      Figure 3.9. Historical trends
                                                                                                      in annual nitrogen and
                        z                   Chowan            Roanoke= Tar
                                                                                                      phosphorus produced in
                            60 -                                                                      excreta of farm animals
                                            Neuse             Coastal
                                                                                                      (millions of kg) in each sub-
                                                                                                      basin of the Albemarle-
                            40-                                                                       Pamlico drainage area, 1880-
                                                                                                      1987.

                        W

                        ,-20-
                        z
                        2
                             0-
                                80 90       0 10 20 30 40 50 59 69 78                        87
                                                    YEAR (1880-1987)

                            25-

                                          CHOWAN             ROANOKE= TAR
                        Z 20 -
                        0           E3 NEUSE                 COASTAL

                            10-
                        Uj

                             5-

                             01
                                80 90           10    20 30 40 50 59 69 78 87
                                                   YEAR (1880-1987)

                               Trends In Nutrient Production                                                                                     41

                               part ofthe AP basin. Total numbers ranged                   Table 3.8. Major nutrient point sources in the
                               between 250,000 and 350,000 up until the                    Albemarle-Pamlico basin. Numbers correspond to
                               1940s, but showed no particular trend.                      ranks inFigure3.10. M =Municipal; I= Industrial.
                               Since then, there has been a general                        Number      Facility                 Type     Sub-basin
                               increase, to around 570,000 today (Figure
                               3.8). Most of the increase has been in the                        1     Raleigh, NC                  M    Neuse
                                                                                                 2     Weyerhaeuser                 I    Roanoke
                               Roanoke River basin, probably in the                              3     Union Camp                   I    Chowan
                               western Piedmont and Appalachian foot-                            4     Weyerhaeuser                 I    Neuse
                               hills sections. Since 1930, the number of                         6     Roanoke, VA                  M    Roanoke
                                                                                                 6     Durham, NC (Northaide)       M    Neuse
                               cattle in that basin has nearly tripled, and                      7     Rocky Mount, NC              M    Tar
                               there has been nearly a doubling in the                           8     Danville, VA                 M    Roanoke
                                                                                                 9     Greenville, NC               M    Tar
                               Chowan basin. But in the more southerly                           10    Cary, NC                     M    Neuse
                               Tar, Neuse, and Coastal basins, the                               11    Wilson, NC                   M    Neuse
                               increases have been much smaller.                                 12    Goldsboro, NC                M    Neuse
                                                                                                 13    Martinsville, VA             M    Roanoke
                                    Numbers of mules peaked in the 1940s                         14    Kinston, NC                  M    Neuse
                               at around 180,000, but they, along with                           16    Texasgulf Chemicals          I    Tar
                               horses and sheep, have become an                                  16    Havelock, NC                 M    Neuse
                                                                                                 17    New Bern, NC                 M    Neuse
                               insignificant part of the total farm animals                      18    Reidsville, NC               M    Roanoke
                               inventory in the past two decades (Figure                         19    Salem, VA                    M    Roanoke
                               3.8). Mules could not compete with tractors,                      20    Eden, NC                     M *  Roanoke
                               which rapidly began to take the place of
                               human and animal power in southern                          transportation for farm families.             Finally,
                               agriculture in the late 1940s. In just two                  sheep raising in the AP basin                 declined
                               decades, between 1950 and 1970, the mule                    rapidly during the first quarter of this
                               had practically disappeared from farms in                   century, as reflected in the inventories,
                               the AP region. Likewise, inventories of                     which went from 155,000 animals in 1880
                               horses had shown a steep decline earlier in                 to only 30,000 by 1925 (Figure 3.8).
                               the 1920s, as automobiles and trucks                              Poultry production in some areas of the
                               became the more common method of                            AP basin has increased dramatically in the

                               Figure 3.10. Rankingofpoint                600-
                               sources in the Albemarle-              cr)
                               Pamlico basin, in terms ofkgN          0   500-
                               producedper year in 1986.              z                          Nitrogen                Phosphorus
                                                                      M   400-
                                                                      0
                                                                          300-

                                                                          200-
                                                                      cc

                                                                      W
                                                                          100-

                                                                             0
                                                                                  1     3        5    7     9 11 13            15 17 19
                                                                                                       1986 RANKING

                     42                                                                                   Chapter 3

                     past two decades. Growth of the poultry            today. Some Piedmont and coastal areas in
                     industry has been one of the most notable          North Carolina have become areas of in-
                     developments in southern agriculture since         tense poultry production. The industry
                     World War 11. Historically, poultry on             tends to be locally concentrated. For
                     most southern farms had been a barnyard            example, in 1987 about one half the total
                     business to provide eggs for the table and         numberof chickens in North Carolina were
                     to earn a little "egg money" for groceries         in only 6 of the State's 100 counties (N.C.
                     and other things. Chicken was not eaten            Department of Agriculture 1988). One
                     regularly but was something families ate           such area is in the central coastal plain,
                     on Sunday and on special occasions.                within the Tar and Neuse River watersheds.
                     Chickens were kept mainly for the eggs.            Thus nearly half of the total broilers and
                     But by the mid- 1940's, there had developed        chickens inventoried in the AP region in
                     "businessmen-farmer teams" for the com-            1987 were in those two sub-basins (Figure
                     mercial production of "eating chickens", or        3.8). Turkey farming is even more focused;
                     "broilers." The businessman hatched the            in 1987, 80% of the total inventory was in
                     eggs, contracted with farmers to raise the         the Neuse basin (Figure 3.8). Total AP
                     chicks on feed that he supplied from his           poultry inventories (broilers, chickens, and
                     mill to growers on credit, and finally pro-        turkeys) grewslowly from around 2 million
                     cessed and marketed the birds. Farmers             in 1880 to approximately 6 million in 1959.
                     provided the housing, labor, and manage-           Since then, however, poultry inventories
                     ment in return for an assured market (Fite         have increased at an amazing rate, so that
                     1984).                                             by 1987 there were over 37 million of these
                         This "vertical integration"of the indus-       animals in the Albemarle-Pamlico Basin.
                     try, along with increased efficiency of feed           N production from farm animals in-
                     utilization, led to lower prices (relative to      creased slowly between 1880 and 1969,
                     other meats). This, i n turn, helped increase      but has increased rapidly since 1969, so
                     consumer demand, producing a boom in               that over the past century this N source
                     broiler and egg production that continues          has almost doubled (Figure 3.9, Appendix

                        5-  ALBEMARLE-PAMLICO BASIN                                           Figure 3.11. 77rends in
                                                                                              point source loadings of
                     -C0 4 -M Industrial                                                      nitrogen     (N)      and
                     Z                                                                        phosphorus (P) fi-om point
                     0             Municipal                                                  sources in the Albemarle-
                        3-                                                                    Pamlico watershed, 1880-
                            N = NITROGEN
                            P = PHOSPHORUS                                                    1887.
                     cr 2 -

                     W

                          80 90 00 10         20 30 40 50          60 70 80       86
                          NP NP NP NP         NP NP NP NP         NP NP NP        NP
                                                    YEAR
                                                                                    n

                          Trends In Nutrient Production                                                                    43

                          3.8). In 1880 animal produced about 40             there is little variation in the level of treat-
                          million kg N, compared to 45 million kg in         ment (i.e., percent N and P removal) within
                          1969. But the 1987 value was almost 75             the region. However, the rate of increase
                          million kg/year. Cattle have contributed           slowed, at least temporarily, about mid-
                          40%-60% of the total animal N in most              century as secondary treatment became
                          census years, and swine have usually made          more widespread (Figure 3.11).
                          the second largest contribution (15%-25%).             In 1986 the estimated total municipal
                          In the past, horses, mules, and poultry also       N and P loading's were 3.07 million kg and
                          made significant contributions to the              1.06 million kg, respectively. About half
                          animal excreta N. But in recent yearsJust          the total N came from cities and towns in
                          three animal types - cattle, swine, and            the Neuse basin, 28% from the Roanoke
                          poultry - have been responsible for more           basin, 16% from the Tarbasin, 5% from the
                          than 95% of the total. Since 1978, the             Chowan basin, and only about 3% from the
                          percentages have been about 50% from               coastal areas (Figure 3.11). Municipal P
                          cattle, 20% from swine, and 30% from               loading was distributed among the basins
                          poultry.                                           in about the same proportions.
                              Animal excreta P amounted to about                 Although the AP basin is relatively
                          11 million kgin 1880, and was only slightly        unindustrialized, there are a few major
                          higher (12 million kg) in 1969. By 1987 the        industries that contribute large quantities
                          animal P had increased to over 21 million          of N and P; in some cases much more than
                          kg/year. The pattern has been similar to           the municipal sources. In 1986 the indus-
                          that for N, both in terms of the changes in        trial sources contributed about 1.04 million
                          production rate, and the percentages con-          kg N and 0.56 million kg P. This amounts
                          tributed by each animal type. In recent            to about one-fourth and one-third the total
                          years about 40% of the P has come from             AP basin point source N and P, respectively.
                          cattle, about 30% from swine, and about            Two types of industries - pulp and paper
                          30% from poultry.                                  mills and phosphate mining - predomi-
                                                                             nate, in terms of N and P production. Most
                          PoInt-Source Nutrient Production                   of these have come to the region since
                              The urban population, and hence the            World War II. There are pulp/paper mills
                          estimated sewered population, in the               on the lower Roanoke River, tributaries of
                          Albemarle-Pamlico, has risen rapidly in            the Chowan river, and the lower Neuse
                          recent years, and today the largest urban          River. Point source loading in the Chowan
                          centers are in the western areas of the sub-       River basin is especially dominated by the
                          basins, primarily in the Raleigh-Durham            industrial sources, which produce about
                          area in North Carolina (Neuse Riverbasin)          twice as much N and P as the municipal
                          and in the Roanoke, Virginia area (Roanoke         plants in this relatively unurbanized basin
                          Riverbasin). A high percentage ofthe total         (Figure3.11). The Tar-Pamlico River pre-
                          municipal loadingcomes from a small num-           sents an unusual situation also. There, the
                          ber of the largest cities (Figure 3.10 and         Texasgulf phosphate mine discharge
                          Table 3.8). Tracking this population in-           dominates the point source P loading. Since
                          crease, point source loading in the AP             it was built in 1964, this single source has
                          basin rose rapidly during the first half of        accounted for two-thirds to three-fourths
                          this century (Figure 3.11, Appendix 3.9),          of the total annual point source P produced
                          and the geographical distribution of the           in the Tar-Pamlico basin.
                          municipal loadinghas corresponded closely
                          to the population patterns, suggestingthat

                     44                                                                             Chapter 3

                        60-

                               A

                        50-

                     z
                     2  40-
                                                                                 POINT SOURCES

                        30-                                                      URBAN RUNOFF

                                                                                 FARM ANIMALS
                     W
                     >- 20-                                                      CROPLAND RUNOFF
                     1-1
                     z                                                           PASTURE RUNOFF
                     0
                     @61. 10-                                                    OTHER RUNOFF

                                                                                 FOREST RUNOFF

                          0-
                            80 90 0 10 20 30 40 50 59 69 78 87
                                             YEAR

                     Figare3.12. Trends in estimated total nitrogen production, from all point and non-point sources, in the
                     Albemarle-Pamlico watershed and from each major sub-basin, 1880-1987.

                                                                       Similar assumptions were made for P,
                     Trends In Total Nuffient Productlon            with one difference; the cropland P produc-
                     by All Sources                                 tion was assumed to be one-fifth of the
                        Time series plots for trends in estimated   computed P balance.
                     total N production from all sources, both         For the whole Albemarle-Pamlico basin,
                     nonpoint and point, are given in Figure        the total annual N production from all
                     3.12. Several important assumptions have       sources is estimated to have nearly doubled
                     been made regarding these estimates:           over the past century, from around 30
                        1. The production by forests, other land    million kg in 1880 to 55 million kg in 1987.
                     (here the sum of two land use types            Between 1880 and 1959, the increase was
                     described above: "other farmland" and          only about5 million kg(18%). Then, prima-
                     "other land"), pasture, and urban lands        rily because of the rapid increase in the
                     was calculated by multiplying acreages         cropland balance in the 1960s, the total N
                     times constant yield coefficients.          I  production rose rapidly, but appears to
                        2. The cropland N production was            have remained nearly constant in the 1970s
                     assumed to be equal to one-third of the        and 1980s.
                     cropland N balance calculated above.              The percentage contributions by each
                        3. Animal N production was assumed          N source have changed greatly over the
                     to be equal to 5% ofthe animal N in excreta. past century. In 1880, the most important

                         Trends in Nutrient Production                                                            45

                             14-
                                   B
                          "12 -
                          z
                          210 -
                          _j
                          _j                                                          POINT SOURCES
                              8-                                                      URBAN RUNOFF

                                                                                      FARM ANIMALS
                              6-
                          W
                                                                                      CROPLAND RUNOFF

                              4-
                                                                                      PASTURE RUNOFF
                          0
                          @e  2-                                                      OTHER RUNOFF
                                                                                      FOREST RUNOFF
                              0-
                                 80 90 0 10 20 30 40 50 59 69 78 87
                                                  YEAR

                         Figure 3.13. Trends in estimated phosphorus production, from all point and non-point sources, in the
                         Albemarle-Pamlico watershed, and from each mqjor sub-basin.

                         sources were forest (45%) and "other" lands    1900s, but is no greater today than in
                         (35%). Pasture and farm animals contrib-       1930, although there have been relatively
                         uted almost all the remainder (Figure 3.12).   large short-term fluctuations. The Coastal
                         Today, according to these estimates, the       basin N production also rose fairly gradu-
                         forest, other lands, and pasture N produc-     ally, from around 3 million kg in 1880 to
                         tion is about the same, in terms of kglyear,   about 5.3 million kg in 1978. In this area,
                         but new sources have diminished the            the increases from cropland have been
                         relative importance of these three. The        offset, to some extent, by decreases from
                         most important new N source is cropland        forest and "other" land. The Roanoke
                         excess N, which now makes up about 30%         basin followed a pattern similar to that for
                         of the total. Animals, urban runoff, and       the Tar and Neuse; i.e., a gradual increase
                         point sources together contribute about        up until the 1950s, followed by a rapid rise
                                                                        in
                         17% of the total.                                 N production in the 1960s. But in the
                             Two of the sub-basins, the Tar and the     Roanoke, the overall increase has not been
                         Neuse, appear to have experienced larger       as great as in the other two sub-basins. In
                         relative increases in N production than the    other words, the Roanoke N product        ion
                         Chowan, Roanoke, or Coastal sub-basins         has increased by about 50% over the past
                         (Figure 3.12). In the Chowan basin, N          century, whereas in the Tar and the Neuse
                         production rose gradually in the early         basins, the increases have been 80% and

                   46                                                                              Chapter 3

                   115 %respectively. Most of this difference      variable. The long-term, gradual increase
                   appears to be due to much greater increases     in P production appears to be continuing,
                   in cropland N balance in the Tar and Neuse      although there was less P produced in 1982
                   than in the less agricultural Roanoke basin.    and 1987 than in the two previous census
                       The most notable difference between         years.
                   total N production and total P production
                   in theAP basin is that P production appears     DiScussion
                   to have declined in recent years, particu-         Likely sources of error associated with
                   larly in the Chowan and Roanoke sub-            the municipal loading estimates include
                   basins (Figure 3.13). For the whole AP          the sewered population values and the
                   watershed, total P production rose rapidly      treatment factors used in the calculations.
                   from around 4.5 million kg in 1880 to           As noted above (see Methods) the sewered
                   nearly 10 million kg by 1920. Following a       population for years before the first munic-
                   decline in the 1930s, the P production rates    ipal treatment plant inventory in 1942
                   began to increase again, reaching an all-       was assumed to be equal to the populations
                   time high of about 12.5 million kg/year         of the cities and towns. This caused some
                   around 1960. Since then, P production has       overestimation of the nutrient loading.
                   fallen back to about 10 million kg/year. So,    However, this errorwouldmake little differ-
                   overall the increase duringthe past century     ence in the overall loading estimates since
                   has been about 110%, but during the past        the "potential" sewered population then
                   quarter century there may have actually         was so small. The problem with using
                   been a 20% decrease. As in the case of N        "treatment factors" is that the facilities in
                   production, much of the change in P pro-        a given city often have not performed at the
                   duction has been caused by changes in the       expected efficiencies, for a number of
                   cropland balance. In recent years, this         reasons, includingstorm-related bypassing
                   source has accounted for about 30% of the       of rawsewage in combined systems, waste-
                   total P; in some years in the 1960s it was      water flows exceeding the design capacity
                   as much as 60% ofthe total. The other new       of the systems, and poor maintenance of
                   P sources, point and urban runoff, make up      the equipment. The latter was reported to
                   about 10% and 3%, respectively, of the          be a serious problem in many cities and
                   total today.                                    towns in the AP basin during the 1950s
                       There are quite large differences in the    (N.C. Stream Sanitation Committee 1959).
                   trends for each of the sub-basins. In the       Thus, the actual nutrient loading would be
                   Chowan and Roanoke, the decreases in            greater than I estimated if this type of
                   recent years are most noticeable, particu-      error became serious.
                   larly in the Chowan. There, the cropland            Nevertheless, comparison of my esti-
                   P mass balance has declined by almost           mates with those made by others using
                   75% since 1954, causing about a 50%             different techniques shows that, for recent
                   decrease in the estimated total P produc-       times at least, the "treatment factors"
                   tion. The same pattern in the Roanoke has       method gives reasonably accurate esti-
                   led to about a 30% decrease. P production       mates. The data I used for comparison
                   in the Tar and Neuse basins appears not to      come primarily from calculations made by
                   have changed greatly in recent times,           multiplying average effluent discharges
                   although there are substantial year-to-         (MGD) times average N and P concentra-
                   year changes. The coastal sub-basin is the      tions in the effluent (mg/1). The products
                   area in the AP watershed where the P            for all municipal plants in the basin are
                   production trend has been the least             then summed to give the total expected

                              Trends In Nutrient Production                                                                                   47

                                      TableS.9. Comparison ofpointsource loadings e8timatedby two different techniques. "Flow
                                      x Con."refem to multiplication ofeffluent discharge rates WGD) times nutrientconcentrations
                                      (mg1 1). "T. Factom"refers to the use oftreatmentfactor8, usedin combination with estimates
                                      ofseweredpopulation. Numbers inparenthe8es (beside kg 1year values) refer to data sources
                                      given at bottom of table.

                                                                         Nitrogen (Ikg@)                       Phosphorus ftlyr)

                                                                "Flow x Con."         'T. Factors"     "Flow x Con."        "T. Factors"
                                      Basin/Year                   Method                Method          Method               Method

                                      Tar-Pamlico (1986-88)
                                          Municipal               545,496(l)            490,542           95,598(1)           165,046
                                          Texasgulf                71,373(l)             70,000         346,647(l)            391,000

                                      Chowan (1980)               881,000(2)            722,798         165,300(2)            136,631

                                      Neuse (1980-82)           1,510,000 (3)         1,470,626         430,000(3)            437,911

                                      'N.C. Division of Environmental Management (1989)
                                      2N.C. Division of Environmental Management (1982)
                                      'N.C. Division of Environmental Management (1983)

                              loading. The results (Table 3.9) agree                     median Neuse Riverbasin N and P effluent
                              reasonably well with my calculations. Note                 levels were 13 mg N/liter and 6 mg P/liter
                              that the 1988 Tar River values reflect a                   (data provided by NC Division of Environ-
                              reduction in P loading that resulted from a                mental Management), which is typical for
                              1987 ban ofphosphate detergents in North                   secondary treatment processes such as
                              Carolina. Thus, this value is approximately                trickling filters and activated sludge.
                              40% lower than my estimate for 1987 (before                     Before 1950 there was no significant N
                              the ban), which is about the same as the                   or P removal from wastewater discharged
                              percentage reduction attributed to the P                   into the rivers of the AP basin. Although
                              detergent ban by state officials (N.C.                     sewage collection systems had been con-
                              DNRCD 1989). 1 had to use the less direct                  structed for most of the larger cities in the
                              "treatment factors"approach because moni-                  early 1900s, as late as 1945 about two
                              toring of treatment plant effluent N and P                 thirds of the sewered population was using
                              concentrations in North Carolina and Vir-                  systems that provided no treatment (N.C.
                              ginia did not begin until about 1980; thus,                Stream Sanitation Committee 1946).
                              the "flow times concentration" method com-                 Rather, the raw sewage was simply dis-
                              monly used today could not be used for                     charged into nearby streams and rivers.
                              estimating historical loadings.                            About half of the sewage that was treated
                                   Gakstatter et al. (1978) surveyed medi-               received only primary treatment, which
                              an P and N concentrations in the effluents                 removes, at best, only about 10% of the N
                              from over 800 municipal wastewater plant                   and P. Thus, N and P loading was growing
                              using various treatment processes. Their                   at about the same rate as the sewered
                              data show that conventional secondary                      population. As secondary treatment came
                              treatment removes little P and only about                  into widespread use in the 1950s and 1960s,
                              25-45% ofthe N. Tertiary treatment consid-                 the overall nutrient removal efficiencies
                              erably increases the N and P removal, but                  increased, causing a slowing in the rate of
                              this advanced treatment is not yet used in                 increase in municipal nutrient loading.
                              enough plants to make a difference in the                  But there has been little additional im-
                              overall loading. For example, in 1985 the                  provement since then because further in-

                     48                                                                                   Chapter 3

                     creases in treatment efficiencies have not         under laboratory or greenhouse conditions.
                     occurred, or have occurred more slowly to          Thomas and Gilliam (1978) concluded that
                     keep up with increases in urban population.        it is generally accepted as beingas accurate
                         The greatest source of error in the non-       as any.
                     point nutrient production estimates un-                The very large increase in the cropland
                     doubtedly comes from uncertainties in the          N balance (inputs minus outputs) between
                     areal export coefficients, rather than from        1959 and 1964 is probably somewhat
                     the acreages. Measured export coefficients         misleading, since N (and P) fertilizer sales
                     were compiled by Beaulac (1980) from               in 1964 seem to have been unusually large,
                     scores of studies and presented in tabular         especially in comparison to the relatively
                     and graphical form in Beaulac and Reckhow          small (for that time) harvest. Nevertheless,
                     (1980). They discussed factors that affect         there was apparently a rather steep
                     the coefficients for each land-use type and        increase in the "excess N"duringthe period
                     urged that for application to a particular         1954-1964. Apparently, yields were not
                     geographic area, only those coefficients           increasing as rapidly as was the rate of
                     from studies in similarareas be considered.        application of N to the croplands. Later, in
                     However, there are two potential problems          the 1970s and 1980s, the fertilization rate
                     in usingthis simple, obvious criterion. First,     seemed to level off, or perhaps decline
                     there may be no data available that seems          slightly. This appears to be the main
                     suitable for a given area, or secondly, there      reason for the stabilization in theNbalance.
                     maybe so much variability in the area to be        It is interestingto note however, that since
                     modeled that choosing a truly representa-          the early 1960s, there appears to have
                     tive coefficient value is very difficult. Unfor-   been no increase in the amount of excess N
                     tunately, most of the studies have been            on croplands. The trend in cropland P
                     made for watersheds with mixed land uses           balance in recentyears is even more surpris-
                     rather thanjust one. Nevertheless, I tried         ing, in that there seems to have been about
                     to choose coefficients as carefully as pos-        a 50% reduction in the cropland "excess" P
                     sible, considering those presented in              since 1954.
                     Beaulac and Reckhow (1980), and in other               Estimating historical trends in
                     sources (e.g., Loehr 1974).                        atmospheric N oxide concentrations is
                         Soil scientists are much more certain          difficult, because of the weak historical
                     about what factors affect rates of                 data base for precipitation chemistry.
                     denitrification than they are about the            Before 1955 there were only sporadic
                     actual rates in the field. Studies in North        measurements (apparently none in the AP
                     Carolina and elsewhere have shown that             basin) and Stansland et al. (1986) have
                     the rate is inversely related to drainage          concluded that their reliability is so
                     and directly related to the presence of soil       questionable that they should not be used
                     horizons which restrict water movement.            for trend analysis. C.E. Junge (1958)
                     Gambrell et al. (1975) measured essentially        published results of the first large scale
                     no denitrification on one moderately well          study of rain water chemistry in the U.S.,
                     drained soil and as much as 60 kg/ha on a          for the period July 1955-July 1956. His set
                     poorly drained soil; both sites were within        of 60 stations included one at Cape
                     the AP basin. The figure of 15% loss of            Hatteras, NC, where NO, concentrations
                     applied N lost by denitrification that I used      ranged generally between 0.15 and 0.30
                     is very frequently used in computations of         mg/liter. Ammonia was also measured; it
                     N balances. Apparently it originated from          fluctuated seasonally but averaged about
                     denitrification experiments conducted              0.04 mg/liter. A more thorough study was

                         Trends in Nutrient Production                                                                49
                         made in the AP basin area about ten years        burned. It is the uncertainty about changes
                         later, and the results were reported in          in the emission factors that is most prob-
                         Fisher (1968). A trend ofincreasingnitrate       lematic. Based on estimates of emission
                         northwest from the coast was found; from         factors and data on fuel consumption, Husar
                         0. 17 to 0.40 mg NO./liter (average annual)      (1986) estimated that in the southeastern
                         in the Pamlico Sound area to 1.00 mg/liter       U.S., N oxides production increased in an
                         in the western end of the Roanoke River          exponential fashion from less than 1 million
                         basin. Ammonium concentrations were              ton/year in 1900 to around 6 million tons/
                         considerably lower, averaging about 0.1          year by the mid- 1970s. Husar showed that
                         mg NH./liter over the whole AP basin.            his results were similar to those of
                         Calculated annual nitrate and ammonium           Gschwandtner et al., (1985) who also esti-
                         loadings for the AP basin were about 2           mated trends in atmospheric N oxide emis-
                         tons/square mile and 0.35 tons/square mile,      sions since 1900.
                         respectively (Fisher 1968).                          Since there are no reliable measure-
                             The most recent data are from stations       ments of AP basin atmospheric N levels
                         that was established in 1978, as a part of       before 1950, 1 was forced to make historical
                         the National Atmospheric Deposition              estimates by combining data on present-
                         Program (NADP). Data from several NADP           day concentrations from remote areas,
                         stations in the AP basin (most in the            current concentration data for the AP basin,
                         Piedmont and Central Coastal Plain areas)        and the suspected exponential rate of in-
                         indicate that between 1981 and 1985 the          crease described above. The remote areas
                         precipitation weighted mean NO,                  values are assumed to represent condi-
                         concentrations (mg/liter) averaged about         tions in the AP area in the late 1800s. The
                         0.9; whereas the NH, averaged around 0.2         values came from NADP data summarized
                         (Olsen and Watson 1984; Olsen and Slavich        by Galloway et al. (1984). They showed
                         1985, 1986; Sweeney and Olsen 1987).             that in the remote areas, the (presumably)
                        .Thus, for purposes of the loading                "background" nitrate levels are around 4
                         calculations, I assumed that total               IiM N (0.23 mg NO./liter). Assuming that
                         atmospheric N concentrations in                  the nitrate:ammonia ratio has not changed,
                         precipitation (NO, + NHS + other combined        I estimated the atmospheric precipitation
                         forms) was approximately 0.36 mg/liter           N for 1880 to have been 0.07 mg/liter (as
                         (as N) in the mid-1980s. Over eastern            N). If this estimate is close to the real 1880
                         North America the total wet and total dry        concentration, then the current (mid 1980s)
                         deposition are thought to be of approxi-         levels would represent about a 5-fold
                         mately equal magnitude (Stansland et al.         increase over the past century.
                         1986); therefore I doubled the calculated           Yet another problem concerningatmos-
                         precipitation loadingto give the total atmo-     pheric N deposition effects on nutrient
                         spheric N loads.                                 production in the AP basin has to do with
                             Another problem in estimating his tori-      the uncertainty about the percentage of
                         cal trends in atmospheric N oxides is that       the increased deposition that actually
                         they are formed primarily by the fixation of     leaves the forest, pasture, or other land.
                         atmospheric N at high temperatures of            Recently, a controversial report on the role
                         combustion rather than by oxidation of the       of acid rain in polluting coastal waters with
                         N contained in the fuels. Thus the "emission     N was prepared by the Environmental
                         factors" (i.e., the rate of N oxide emission     Defense Fund (Fisher et al. 1988). This
                         per unit of fuel N) have to be taken into        EDF report contended that one-fourth of
                         account, as well as the quantities of fuel       all N contributed by human activity to the

                     50                                                                                 Chapter 3

                     Chesapeake Bay originates in acid rain            came to a similar conclusion after compar-
                     and associated dry deposition falling             ingprecipitation nitrate loadingand stream
                     directly on the bay or onto its watershed.        nitrate transport for several areas within
                     Atmospheric N, it was concluded, exceeds          the AP basin.
                     sewage outfalls and runoffof animal waste            The relatively low values and small
                     as a N source to the bay. These results           geographical variability in forest may also
                     were based on an assumption that forests          give some indirect indication that historical
                     retain 80% of the atmospheric N, pasture          increases in atmospheric N deposition have
                     and croplands, retain 70%, and urban lands        not made such a large impact on the total
                     35%. Given that atmospheric N deposition          AP basin nutrient export as might be ex-
                     is so large in comparison to other present-       pected. Forest N yield estimates available
                     day inputs, it is no surprise that even if        in the literature are nearly all from studies
                     0%-30% (from forests and croplands) of            carried out during the past two decades;
                     the atmospheric N is assumed to leave the         i.e., recent enough to reflect effects of the
                     and, then this becomes an important               relatively high atmospheric N deposition
                     contribution to the streams and estuaries         rates that developed by the middle of this
                     - especially when it is assumed (as both          century.
                     EDF and I did) that only 5% of animal N              The N and P loading estimates made by
                     leaves the pastures and other sites of            others for the Chowan, Neuse and Tar
                     production.                                       River basins are roughly one-third to one-
                         But as the re* port noted, there is consid-   half the 1987 estimated total N and P
                     erhble variability in measures losses of          production calculated above (compare Table
                     atmospheric N from various land use cate-         1.3, Chapter 1 with Figures 3.12 and 3.13).
                     gories; in some studies in areas similar to       But those other estimates were also made
                     those drainedby the rivers in the AP basin,       using-in most cases -some combination
                     the retention of atmospheric N has been           of land use yield coefficients, instream. flow
                     found to be very high. Weller et al. (1986),      times nutrient concentration calculations,
                     for example, found that a coastal plain           and summed point source loading. It would
                     watershed in Virginia retained 97% of the         probably be futile to try to determine the
                     atmospheric N deposited on it, and in a           reasons for the differences in each case, but
                     recently-published book on forest nutrition       I suspect that the major difference has to
                     management it was stated that"withsome            do with the use oftheir instream concentra-
                     notable exceptions (such as high elevation        tion times flow calculations vs. my reliance
                     spruce/fir forests in the northeastern United     on cropland mass balances, and land use
                     States), the majority of forest ecosystems        coefficients. In general, the actual instream.
                     are N limited, so most nitrate deposited in       nutrient loads, and the loading to the
                     acid rain is retained - indeed, nitric acid       estuaries, is considerably less than the
                     may fertilize forest ecosystems" (Binkley         quantities of nutrients produced at the
                     1986, p. 208). Thus, forests appear to            sources, as was mentioned in the intro-
                     "buffer" a large part of the atmospheric N        duction to this chapter.
                     they intercept. For example, Lowrance et             Of course, there is no long-term his-
                     al. (1985) showed that for several                torical instream data for any part of the AP
                     agricultural-forested watersheds in Geor-         basin that could be used for comparison
                     gia, the N output via streamflow was always       with the nutrient production estimates
                     considerably less than the atmospheric N          presented here, but there are at least some
                     input, despite considerable additional N          recent instream data for comparison. Chris-
                     input from fertilization. Fisher (1968)           tian et al. (1987) have monitored N and P

                           Trends in Nutrient Production                                                                51

                           concentrations in the lower Neuse River         basins, has lead to greatly increased N and
                           above New Bern. They multiplied N and P         P loading in recent years. I have assumed
                           concentrations in grab samples times mean       that only 5% of the N and P produced by
                           daily river flows to give total annual in-      farm animals leaves the pastures, feedlots,
                           stream loading estimates. Their results,        and barns. However, if the loss were
                           3.5 million kg N per year and 0. 8 million kg   increased to 10% or 15%, then there would
                           P/year, are 1/4 as large as my N estimate       be a substantial impact on the total nutrient
                           and 1/3 as large as my P estimate for           production. Such an increase may not be
                           nutrient production in the Neuse Basin.         unrealistic, given that many ofthese animal
                           This difference is similar to what Craig and    operations involve the use of feed lots or
                           Kuenzler (1983) found in a similar              buildings in which hundreds (swine) to
                           comparison for the Chowan River. Their          tens-of-thousands (poultry) of animals are
                           explanation was that lowland swamp              confined in very small areas. In such cases,
                           forests along these coastal rivers represent    these become essentially point discharges,
                           a major sinks for nutrients, removing 83%       and indeed the wastes are now often treated
                           of the total N and 51% of the total P from      by aeration lagoons or other techniques
                           water draining into the lower Chowan.           similar to those employed by conventional
                           Such losses, Kuenzler (1989) noted, are         municipal treatment plants. Unfortu-
                           within the range of values derived from         nately, however, the animal waste treat-
                           detailed input-output studies of swamp          ment facilities are not nearly as strongly
                           forests within the Southeast.                   regulated as municipal point sources, but
                               It is clear from the historical trend data  North Carolina State officials are becoming
                           presented above that the rapidly increasing     increasingly wary ofthe potential problems
                           farm animal numbers, particularly swine         (North Carolina DNRCD 1986).
                           and poultry, in the Neuse and Tar-Pamlico

                          CHAPTER4
                          Pamlico River Estuary
                          Water Quality Trends

                          History of Water Quality Studies                     "In reality, nutrients are choking us.
                          in the Albema rle- Pamlico                           There's no doubt about it. That river out
                          System                                               there is dying because of its nutrient load.
                                                                               That's my opinion and many other
                             Very   little hydrographic and water              fishermen's opinion on this river. "
                          quality data have been collected for the             I                        W. Phillips (1987)
                          open waters of the Pamlico Sound. The            small boats that are often used to sample
                          North Carolina Division of Environmental         in the river estuaries.
                          Management has never included the sound              Also, there are no major permanent
                          proper in its water quality monitoring pro-      university or government research labora-
                          gram, and university researchers also have       tories on the shores of either the Albemarle
                          shied away from the sound as a site for          or Pamlico Sounds. Researchers from the
                          their studies. Before 1963, temperature          Duke University and University of North
                          and salinity were the only hydrographic          Carolina labs in the Morehead City-Beau-
                          variables that had been monitored there.         fort, NC, area seldom venture northward
                          The data were from surveys published by          into Pamlico Sound. Rather, most of the
                          Winslow (1889), Grave (1904), Coker              research on water quality in the Pamlico
                          (1907), and Roelofs and Bumpus (1953).           and Albemarle Sound region has been car-
                          Woods (1967) collected temperature, salin-       ried out by scientists from three State
                          ity, dissolved oxygen, chlorophyll a, and        university campuses farther inland: North
                          total phosphorus data from June 1963 to          Carolina State University in Raleigh, the
                          October 1966. His stations were located in       University of North Carolina at Chapel
                          southwestern Pamlico Sound and in the            Hill, and East Carolina University at
                          lower Tar-Pamlico and Neuse River estu-          Greenville.
                          aries, and they were sampled monthly.                Since the early 1960s, researchers from
                          Apparently, these are the only Do and            these institutions have, for the most part,
                          nutrient data ever collected in the Sound.       focused their attention in three areas:
                          Data for the open waters of Albemarle            1) the Pamlico River Estuary, 2) theNeuse
                          Sound are also sparse, except for a two-         River Estuary, and 3) western Albemarle
                          year period of intensive sampling during         Sound (Chowan River and the lower
                          the early 1970s (Bowden and Hobbie 1977).        Roanoke River). These are also the sites
                             Probably the most important reason            where the North Carolina state agencies,
                          for this lack of attention to the sounds is the  principally the Division of Environmental
                          perception that the most serious water           Management and the Division of Marine
                          quality problems are confined to the tribu-      Fisheries, have made most of their studies.
                          tary river estuaries along their western             The Pamlico River is one of the few
                          shores. Another factor is that the sounds        areas in the Albemarle-Pamlico system for
                          are too shallow for even small oceanographic     which there is enough water quality data
                          research vessels, and too large for the          to permit a time series analysis of trends.

                     54                                                                               Chapter 4

                     It is, in fact, one of the most thoroughly       for most other estuaries in the region.
                     monitored estuaries in the Southeast             Routine monitoring of nutrients began in
                     region. Since the mid-1960s, there have          1967 and was continued through 1973.
                     been numerous ecological research and            Various hydrographic variables (salinity,
                     monitoring projects, funded by both the          dissolved oxygen, temperature, pH, and
                     phosphate mining industry (Texasgulf, Inc.       chlorophyll a) were also measured. Since
                     and North Carolina Phosphate Corpora-            1975, the sampling for N and P nutrients
                     tion) and government agencies (principally       and related hydrography has continued
                     the University of North Carolina Water           uninterrupted, thanks to a co-operative
                     Resources Research Institute and the UNC         agreement between Texasgulf, Inc. and
                     Sea Grant College Program).                      the Institute for Coastal and Marine Re-
                         Research topics have included basic          sources at East Carolina University. In
                     hydrography and water-column nutrient            addition to these monitoring efforts, two
                     dynamics (Hobbie 1970a, 1970b, 1974;             Pamlico research projects (Davis et al.
                     Hobbie et al. 1972; Copeland and Hobbie          1978; Kuenzler et al. 1979) collected signif-
                     1972; Harrison and Hobbie 1974; Hobbie           icant amounts of nutrient and hydrography
                     et al. 1975; Lauria and O'Melia 1980;            data between 1975 and 1977. Despite the
                     Kuenzler et al. 1979; Stanley 1984b, 1986a,      accumulation of a large quantity of data, it
                     1986b, 1987, 1988a, 1989), sediment bio-         has never been analyzed in the kind of
                     geochemistry and benthic nutrient cycling        thorough, systematic fashion that would
                     (Matson et al. 1983; Kuenzler et al. 1984),      be needed to address some of the growing
                     organic carbon and deoxygenation (Sick           environmental issues for the estuary.
                     1967; Davis et al. 1978), bacteria hetero-
                     trophy (Crawford et al. 1974), phyto-            Methods
                     plankton ecology (Sherk 1969, Hobbie 197 1;      Data Sources
                     Carpenter 1971a, 1971b; Stanley 1983,               The nutrient and hydrographic data
                     1984a; Stanley and Daniel 1985a, 1985b,          used in this study were produced by two
                     1986), submerged macrophytes (Davis and          long-term monitoring studies and two
                     Brinson 1976, 1989), distribution and bio-       shorter-term research projects. The first
                     mass of ctenophores (Miller 1974), zoo-          monitoring study ran from 1967 to 1973
                     plankton abundance (Peters 1968), meio-          and was led by John Hobbie of North
                     benthos (Reid 1970, 1978), macrobenthos          Carolina State University. It was supported
                     (Tenore 1968, 1970, 1972), fish (Miller and      by funds from two sources: 1) the Office of
                     Dunn 1980; Currin et al. 1984); and fish         Water Resources Research, U.S. Depart-
                     disease (Noga et al. 1989). Much of this         ment ofthe Interior, through the University
                     work has been summarized in an estuarine         of North Carolina Water Resources Re-
                     profile prepared for the U.S. Fish and           search Institute, and 2) Texas Gulf Sulfur
                     Wildlife Service by Copeland et al. (19,84).     Company (nowTexasgulf, Inc.). The initial
                     In addition, several studies of the tribu-       objective was to study the effects of phos-
                     taries of SouthCreekwere presentedinthe          phorus from the phosphate mining opera-
                     Journal of the Elisha Mitchell Scientific        tion (Copeland and Hobbie 1972). Later
                     Society (Volume 10 1, No. 2, 1985).              the scope of the project was broadened to
                         Nitrogen and phosphorus dynamics             include nitrogen.
                     have continued to receive a great deal of           After the NC State University sampling
                     attention by Pamlico investigators since         ended, there was an 18-month lapse until
                     the late 1960s. Consequently, there is           East Carolina University began a new
                     much more nutrient data for the river than       program in January 1975. This study was

                         Pamlico River Estuary Water Quality Trends                                                   55
                         made possible by funds provided by Texas-        phosphorus measurements were substi-
                         gulfto the University's Institute forCoastal     tuted for the total N and P analyses, but
                         and Marine Resources (ICMR). This pro-           the totals can still be computed by summa-
                         gram has run continuously since 1975.            tion of the dissolved and particulate
                             In addition to these two long-term moni-     fractions.
                         toring programs, there were two research            Texasgulf has maintained weather in-
                         projects in the mid-1970s which produced         struments at their plant on the south shore
                         significant amounts of nutrient and hydro-       of the Pamlico River since before 1969. The
                         graphic data. One was an investigation of        company provided data on wind (total miles
                         nitrogen and phosphorus cycling in the           per day), precipitation, and air temperature
                         estuary that was headed by Ed Kuenzler of        for the trend analyses. The U.S. Geological
                         the University ofNorth Carolina at Chapel        Survey maintains a flow gauging station
                         Hill. The other research project, under the      on the Tar River near Tarboro, NC. Their
                         direction of Graham Davis and Mark Brin-         data (daily average cfs) are published each
                         son from the Biology Department at East          year in the "Water Resources Data" series
                         Carolina University, dealt primarily with        (e.g., USGS 1987).
                         organic carbon and deoxygenation in the             I have also compiled information on
                         Pamlico River. Both of these projects were       station locations and identification num-
                         funded by the UNC Water Resources                bers used by the four studies (Appendix
                         Research Institute.                              4.2). The exact locations of the ICMR
                             Nutrient and hydrographic data from          stations (1975-1986) are known. However,
                         these studies are contained in 18 project        I had to estimate the latitude and longitude
                         completion reports and technical reports         for each of the stations used in the three
                         (Appendix 4.1). Rather than cite each of         other studies, because the reports show
                         these, I will often refer to the four projects   them on maps, but give no precise locations.
                         as: 1) "Hobbie," 2) 91CMR," 3) "Davis et         Notice that in some cases, stations from
                         al.," and 4) "Kuenzler et al    ... ..  Hobbie"  different projects were located at the same
                         refers to all the data collected between         position. For example, stations 22 and 1
                         1967 and 1973, and "ICMW' to the East            used by Davis et al. were at the same
                         Carolina University monitoring program           position as ICMR station 11 sampled be-
                         (1975-1990).                                     tween January and June 1975, and ICMR
                            In 1967, only surface water tempera-          station 12 sampled since July 1975.
                         ture, salinity and phosphorus concentra-
                         tions were monitored. Bottom water tem-          Changes in Analytical Methods
                         perature and salinity were added in mid-            A potentially serious problem in a study
                         1968, and surface and bottom water oxygen        of this kind is that samplingand analytical
                         in late 1968. Then in mid-1969, Hobbie           methodologies may have varied so much
                         expanded the program again to include            over the years that comparison of the data
                         surface water pH, and two surface nitrogen       is impossible. Therefore, I have reviewed
                         fractions (ammonia and nitrate). Finally,        and compiled notes on the methods used by
                         in 1970, surface water total nitrogen, total     the four projects. These notes are in Appen-
                         dissolved nitrogen and chlorophyll a were        dix 4.3 and are summarized in Table 4.1.
                         added to the suite of parameters analyzed.
                         Fortunately, all these parameters except         Trend Analysis Techniques
                         two have continued to be measured up                It soon became apparent that the time
                         until the present. In 1985 surface water         series analyses would be impossible unless
                         particulate nitrogen and particulate             I grouped the stations, because in the early

                          56                                                                                                       Chapter 4

                          Table 4.1. Methods used for Pamlico nutrient and hydrographic measurement8.
                          Parameter                   Study              Instrument or Method                                          Reference

                          1. Water temperature        Hobbie             Thermistor                                                               A
                                                      Kuenzler           Thermistor                                                               A
                                                      Davis              Thermistor                                                               B
                                                      ICMR               Thermistor                                                               B

                          2. Salinity                 Hobbie             Induction salinometer                                                    A
                                                      Kuenzler           Induction salinometer                                                    A
                                                      Davis              Conductivity probe                                                       B
                                                      ICMR               Conductivity probe                                                       B
                          3. Dissolved oxygen         Hobbie             Winkler titration                                                        C
                                                      Kuenzler           Winkler titration                                                        D
                                                      Davis              Oxygen electrode                                                         E
                                                      ICMR               Oxygen electrode                                                         E
                          4. pH                       Hobbie             Electrode                                                                F
                                                      Kuenzler           Electrode                                                                F
                                                      Davis              Electrode                                                                G
                                                      ICMR               Electrode                                                                H
                          6. Total phosphorus         Hobbie             Persulfate digestion/mixed color reagent                                 1,J,K
                                                      Kuenzler           Persulfate digestion/automated mixed color reagent                       L
                                                      Davis              Persulfate digestion/mixed color reagent                                 M
                                                      ICMR               Persulfate digestion/mixed color reagent (automated in 1985)            L,M,N

                          6. Total dissolved          Hobbie             Persulfate digestion/mixed color reagent                                 IK
                            phosphorus                Kuenzler           Persulfate digestion/automated mixed colore reagent                      L
                                                      Davis              Persulfate digestion/mixed color reagent                                 M
                                                      ICMR               Persulfate digestion/mixed color reagent (automated in 1985)             N
                          7. Orthophosphate,          Hobbie             Mixed color reagent                                                      I,K
                            phosphorus                Kuenzler           Mixed color reagent (automated)                                          L
                                                      Davis              Mixed color reagent                                                      M
                                                      ICMR               Mixed color reagent (automated in 1985)                                  N
                          8. Ammonia nitrogen         Hobbie             Alkaline hypochlorite/nitrite diazotization                              O,K
                                                      Kuenzler           Indophenol.                                                              L
                                                      Davis              Indophenol                                                              P,Q
                                                      ICMR (1975-79)     Ion selective electrode                                                  R
                                                             (1980-86)   Indophenol.                                                              P
                          9. Nitrate nitrogen         Hobbie             Cadmium reduction/nitrite diazotization                                  S,K
                                                      Kuenzler           Cadmium reduction (automated/nitmte diazotization                       L
                                                      Davis              UV spectrophotometric                                                    T
                                                      ICMR (1975)        Brucine                                                                  T
                                                             (1975-86)   Cadmium reduction/nitrite diazotization. (automated 1985)                U

                          10. Total dissolved         Hobbie             UV oxidation/nitrite diazotization                                       V,K
                             nitrogen                 Kuenzler           Keldahl (automated)                                                     L
                                                      Davis              Keldahl                                                                 M
                                                      ICMR (1975-79)     Keldahl/ammonia electrode                                               L
                                                             (1980-86)   Kjeldahl/indophenol                                                     L,P
                                                             (1985-86)   Persulfate digestionfindophenol                                          N
                          11. Total nitrogen          Hobbie             UV oxidation/nitrite diazotization                                       V,K
                                                      Davis              Keldahl                                                                M
                                                      ICMR (1975-79)     Keldahl/ammonia electrode                                               L
                                                             (1980-85)   Keldahl/indophenol                                                      L,P
                                                             (1985-86)   Persulfate digestion/indophenol                                         N

                             Pamlico River Estuary Water Quality Trends                                                                        57

                             Table 4.1. continued

                             Parameter                 Study            Instrument or Method                                         Reference

                             12. Particulate N and P   ICMR (1986-86)   Persulfate digestion/indophenol                                    N

                             13. Chlorophyll a         Hobbie           Acetone extraction/spectrophotometric                             FU
                                                       KuenzIer         Acetone extraction/spectrophotometric                              w
                                                       Davis            Acetone extraction/spectrophotometric                              U
                                                       ICMR             Acetone extraction/spectrophotometric                              U

                             14. Phytoplankton         Hobbie           Utermohl concentration/light microscopy                            X
                                                       ICMR             Membrane filtration ooncentration/light microscopy                 D

                             A. Beckman induction Salinometer Model RS5-3 meter and probe
                             B. Yellow Springs Instrument Co. Model 33 S-C-T meter and probe
                             C. Carpenter (1965)
                             D. American Public Health Association (1976)
                             E. Yellow Springs Instrument Co. Model 61A meter and probe
                             F. Unknown
                             G. Coming Model 10
                             H. Various instruments used
                             1. Menzel and Corwin (1965)
                             J. Murphy and Riley (1962)
                             K. Strickland and Parsons (1968)
                             L. U.S. Environmental Protection Agency (1974)
                             M. U.S. Environmental Protection Agency (1976)
                             N. U.S. Environmental Protection Agency (1979)
                             0. Richards and lGetch (1961)
                             P. Solorzano (1969)
                             Q. Scheiner (1976)
                             R. Orion Model ?
                             S. Morris and Riley (1963)
                             T. American Public Health Association (1971)
                             U. Strickland and Parsons (1972)
                             V. Armstrong et al. (1966)
                             W. Lorenzen (1967)
                             X. Utermohl (1958)

                             years many of them were sampled for                         Results and Discussion
                             relatively short periods. Also there have                        It is very important that the reader
                             been only a few locations sampled during                    keep in mind the purpose and limitations
                             all of the 20-year study period. Therefore,                 of trend analysis. First, one wishes to
                             I partitioned the river into ten segments,                  know whether or not there has been a
                             A-J, with boundaries as shown in Figure                     statistically significant change in the
                             4. 1. Appendix 4.2 indicates which sampling                 parameter under examination. This is the
                             stations fall into each of the segments.                    one question which is directly addressed by
                                 The Seasonal Kendall-Tau test indi-                     the Seasonal Kendall test. If a trend is
                             cated there were no long-term trends in                     determined to be significant, the next ques-
                             flow, salinity, delta Sigma-t, or DO in the                 tion is: "How large is the changeT'Remem-
                             Pamlico between 1975 and 1989. For each                     ber that "significant change," as used in a
                             of the four stations, none of the test results              statistical context, does not necessarily
                             were significant at the 90% level (a<0.1)                   mean large. The Kendall slope gives an
                                                                                         estimate of the average rate of change over
                                                                                         the whole test period. But even though the
                                                                                         slope estimate might be large, it is meaning-
                                                                                         less unless the trend is determined to be

                      58                                                                                 Chapter 4
                      statistically significant. Ontheotherhand,        there is a functional relationship between
                      some statistically significant trends might       the variables. As long as one remembers
                      have very small slopes.                           that the statistical results cannot prove or
                          Also, keep in mind that the Kendall           disprove the connection, there is nothing
                      test measures monotonic changes over the          wrongwith consideringthem to be evidence
                      whole test period; it cannot detect short-        of a possible relationship.
                      term ups and downs during that period.
                      Therefore, the outcome ofthe test naturally       Climatic Factors and River Flow
                      will be influenced somewhat by the time              Three climatic variables (air tempera-
                      interval chosen. Even in instances where          ture, wind, precipitation) and river flow
                      there are no reversals in the trend, the rate     were included in the Pamlico trend analysis
                      of increase or decrease might vary, but the       because changes in these variables, espe-
                      slope estimator will give no information          cially river flow, might help explain trends
                      about these rate changes.                         in some of the other variables of more
                          Obviously, the trend analysis results         direct concern. However, as will be shown
                      cannot explain the causes for significant         below, only one of these four factors has
                      trends in the variables. Nevertheless, it is      changed significantly over the past twenty
                      tempting to assume a cause and effect             years.
                      relationship between two parameters when             Air temperatures at the Texasgulfplant
                      the trend in one could logically explain a        on the south side of the river are usually
                      trend in the other. This is a dangerous trap      lowest in January, averaging around 42'F
                      which one must constantly be aware of             (5.5'Q, while July temperatures average
                      during the course of a study like this. On        higher than any other month, around 80'F
                      the other hand, it is certainly possible that

                                                                                                    7111-30-

                                                               KILOMETERS

                                                         0     5     10    is

                                           WASHINGTON

                                                 J6
                                           A
                               35*30'

                                                         C
                                                                                       o.
                                                                 D                   Y.
                                                                           E           !te
                                                                     T6              F
                                                                                            G

                      Figure 4.1. Map showing division of the Pamlico River estuary into ten segments used in the trend
                      analyses.

                               Pamlico River Estuary Water Quality Trends                                                                            59

                                                         Table 4.2. Seasonal Kendall Test results for air temperature,
                                                         wind, precipitation and Tar River flow.

                                                                                                              Time Interval

                                                         Parameter                                      1967-1986       1975-1986

                                                         Monthly Mean Air Temperature          z           0.307           1.821
                                                                                               Slope       0.017           0.129
                                                                                               P           0.719           0.069*

                                                         Total Wind Miles                      z           0.831           1.128
                                                                                               Slope       0.192           0.409
                                                                                               P           0.407           0.358

                                                         Total Monthly Precipitation           z           0.447
                                                                                               Slope       0.000
                                                                                               P           0.653

                                                         Monthly Mean Tar River Flow           z           0.253
                                                                                               Slope       1.750
                                                                                               P           0.803

                                                         P<0.1     (Significant)
                                                         P<0.01      (Highly Significant)

                               (26.60C) (Figure 4.2). Over the past 20
                               years, the variation in the monthly means
                               has been greater in the winter (up to 12"F                            90
                               above normal for January) than in the                                 80   A
                               summer. This difference is also clearly                       Z E. 70
                               shown in Figure 4.2, which shows that                         6 -@
                                                                                                 a.  60
                                                                                                 m
                               there has been little variability in the                          w   50
                               summers, while the winters were relatively                    7( @    40
                               warm in the 1971-1975 period, very cold in                            301                                                1
                               1976 and 1977, and have tended to be                                  1965      1970      1975     1980      1985      1990
                               warmer each year since the late 1970s.                                                        YEAR
                                    Despite these fluctuations in the winter                   ir    90    B
                               and summer maxima temperatures, the                             ;-(   80
                               Seasonal Kendall test results were that                         Z C 70
                                                                                               6-
                                                                                                     Q: 60
                               there was no statistically significant trend                    22
                               in the mean monthly air temperature be-                               50    M
                               tween 1967 and 1986 (Table 4.2). However,                             40           IN.
                                                                                                     30
                               since 1975, there has been a significant (p                                 J F    M A M J J A S 0 N D
                               = .069) upward trend, averaging 0.13'F                                                        MONTH
                               per year.                                                     Figure 4.2. Daily mean air temperature (7),
                                    For any given month there can be great                   averaged by month, at the Texasgulf Chemicals Co.
                               year-to-year variability in the average daily                 plant on the south shore of the Pamlico River
                               wind (Figure 4.3) but the overall pattern is                  estuary. (A) monthly averages, January 1969-
                               that average velocities are highest in late                   December 1986. (B) maximum, minimum and
                               winter and lowest in late summer. The                         median of averages for each month.
                               difference between the March and August
                               wind velocities averages around 30 percent

                        60                                                                                      Chapter 4

                        (115 total miles vs. 78 total miles per day).       evapotranspiration that occurs during the
                        Again, however, the interannual variability         summer. Daily mean flows at Tarboro,
                        is great, so that some summer months                averaged by month, normally vary from
                        have had higher winds than the average              about 800 cfs in September to around 4000
                        for the winter months. Overall, there was           efs in March (Figure 4.5b). Changes i      'n flow
                        no trend toward increasing or decreasing            can be very sudden and of great magnitude
                        winds during the 1967-1986 period (Table            (Figure 4.5a).
                        4.2).                                                    There have been some short-term
                             Monthly precipitation at the Texasgulf         trends in Tar River flow, but no overall,
                        plant has ranged from less than 0.5 inches          long-term change since 1967. Figure 4.5a
                        to over 17 inches during the study period           shows, for example, that between 1984
                        (Figure 4.4), but normally it peaks at around       and 1986, there was a decrease in the late
                        6 inches in July and is lowest in November,         winter and early spring flows. A decline in
                        about 2.5 inches. The Seasonal Kendall              winter flows also occurred between 1979
                        test showed no significant trend in the             and 1981. Overall, 1981 was the lowest
                        monthly precipitation totals between 1967           flow year in the study period. Other low
                        and 1986 (Table 4.2).                               flow years were 1967, 1974, and 1986.
                             Even though precipitation onto the             However, the Seasonal Kendall test for the
                        watershed is highest in the summer, Tar             two decades between 1967 and 1986 gave
                        River flow is usually highest in the late           no significant upward or downward trend
                        winter months, a pattern that is typical for        in the mean monthly flow (Table 4.2).
                        eastern North Carolina (Giese et al. 1979)
                        and the region (Nixon 1983). This seasonal                  2
                        pattern is caused by the increased                     >, 6     A
                                                                               @ 1': 15
                                                                               z 0
                          a  150                                               0    10
                          W                   VIM.                     A
                                                                               _j
                             120    ME j I
                                                                                 W   5
                                                                                 cc
                              go    MIN.                                         IL  0
                                                                                     1969      1974     1979      1984      1989
                              60
                          Z                                                                             YEAR
                              30
                                  J F M A M J J A S 0 N D
                                                  MONTH                          20

                             160
                          W                                           B          15
                             120
                          _j                                                   < 10
                          @<- 80                                               z        AX               MEAN
                          0
                          t__                                                      5
                              40
                          Z
                                                                                   0.
                                0
                                1965   1970    1975   1980    1985    1990            J F M A M J J           A S 0 N D

                                                  YEAR
                        Figure 4.3. Wind (total milesper day), averaged by  Figure4.4. Total monthlyprecipitation (inches) at
                        month, at the Texasgulf Chemicals Co. plant on the  the Texa8gulf Chemicals Co. plant on the south
                        south shore of the Pamlico River estuary. (A)       shore of the Pamlico River estuary. (A) Monthly
                        Monthly averages, January 1969-December 1986.       totals, January 1969-December 1986. (B) Maximum,
                        (B) Maximum, minimum, and median of monthly         minimum, and median of totals for each month.
                        averages.

                             Pamlico River Estuary Wafer Quality Trends                                                                    61
                             Water Temperature, SalInIty and pH                             10000                                     A
                                 Water temperature is the most predict-                         8000

                             able of all the parameters that have been                      6000

                             monitored in the Pamlico studies. Surface                      4000
                             temperatures in the estuary typically range                          2000
                             from around 4C to about 3C over the

                             course of the year (Figure 4.6). The lowest                           1965 1970 1975 1980 1985 1990
                             temperatures occur in January in most
                             years, and the peak temperatures come in                                                   YEAR
                             JulyandAugust. On some samplingdates,                          12000
                                                                                                                                            B
                             there is as much as 5C variation in temper-                    10000
                             atures, but much ofthis difference probably                     8000
                             results from the samples being taken at                         6000
                             different times of the day. It takes 4-6                                 MEAN
                                                                                            4000
                             hours to visit all the stations in the estuary.
                             Bottom water temperatures exhibit the                          2000
                             same seasonal pattern and range as the                              0  J   F M A M J J A S 0 N D
                             surface temperatures. Occasionally there                                                MONTH
                             is strongthermal stratification in the water
                             column, but this is rare. Normally the                  Figure 4.5.      Daily mean flow cfs), averaged by
                             difference between surface and bottom tem-                month, of the Tar River at Tarboro, NC. (A)
                                                                                       Monthly averages, January 1967-December 1986.
                             peratures is less than 2C (e.g., Stanley                 (B) Maximum, minimum, and median of averages
                             1988a). The Seasonal Kendall test indi-                   for each month.
                             cated no significant trend in surface water
                             temperature (Table 4.3) for the three river
                             segments examined. Likewise, no trends
                             were found in the bottom water tempera-
                             ture data (Table 4.3).

                             Figure 4.6. Surface water                   12
                             temperature (C)in  thePamlico              11
                                                                                                                                                                                            10
                             River estuary during 1984, as a               9
                             function of time (x-axis) and                  8
                             distance (-axis). Top of plot is       T

                             station 12 upriver (see Methods        A    7N
                             for explanation of distance            T    TS
                                                                    I    6
                             scale).
                                                                    0     5
                                                                    N    4
    											   3
    												2
    											1A
    											1
    											J   F    M  A   M   J   J   A  S   O   N   D
                                                                         SURFACE TEMPERATURE (O)
                                                                               S-12   12-18   18-24 24-38  30

                         62                                                                                        Chapter 4

                         Table 4.3. Seasonal Kendall Test results. Segment B = Upriver, Segment E = Midriver, Segment H
                         Downriver. P<0.1      (Signiftcant); P<0.01      (Highly Significant).

                                                                               River Segments and Time Intervals

                                                                            1967-1986                       1975-1986

                         Parameter                                     B        E         H           B         E         H

                         Surface Dissolved Oxygen         z          3.745     3.292     4.301      1.172     3.089     2.268
                                                          Slope      0.060     0.050     0.080      0.030     0.090     0.090
                                                          P          0.002     0.002    <0.002      0.242    <0.002     0.023

                         Bottom Dissolved Oxygen          z          -1.560    1.310    -1.830     -0.930    -0.880     -0.180
                                                          Slope      0.040     0.030    -0.060     -0.040    -0.040     -0.020
                                                          P          0.120     0.190     0.067      0.352     0.384     0.857

                         Bottom Dissolved Oxygen          z          -1.624    1.593    -2.217     -1.696    -0.376     -0.721
                         % Saturation                     Slope      -0.406    0.400    -0.523     -1.100    -0.130     -0.446
                                                          P          0.103     0.112     0.027      0.091     0.704     0.472

                         Surface Salinity                 z          2.220     0.600    -1.530      0.690     0.930     -1.070
                                                          Slope      0.050     0.030    -0.100      0.030     0.090     -0.130
                                                          P          0.026     0.555     0.124      0.490     0.352     0.285

                         Bottom Salinity                  z          1.930    -1.090    -2.830     -1.280     0.930     -0.100
                                                          Slope      0.070    -0.060    -0.130      0.110     0.090     -0.010
                                                          P          0.054     0.276     0.005      0.201     0.352     0.920

                         Surface Temperature              z          -0.240   -0.100    -0.430      0.420     0.890     0.870
                                                          Slope      -0.025   -0.019    -0.060      0.144     0.231     0.317
                                                          P          0.810     0.920     0.667      0.674     0.373     0.384

                         Bottom Temperature               z          0.103     0.270     1.456      0.409     1.067     0.830
                                                          Slope      0.003     0.006     0.046      0.022     0.033     0.050
                                                          P          0.912     0.787     0.147      0.682     0.285     0.412

                         pH                               z          -0.716   -3.543    -3.752      0.397     2.158     0.070
                                                          Slope      -0.006   -0.039    -0.037      0.012     0.042     0.021
                                                          P          0.478    <0.002    <0.002      0.697     0.032     0.484

                         Orthophosphate P                 z          1.390     2.070     2.880      1.489    -1.136     3.141
                                                          Slope      0.025     0.080     0.040      0.051    -0.077     0.086
                                                          P          0.165     0.040     0.004      0.136     0.254     0.003

                         Total Phosphorus                 z          4.453     4.699     5.547      1.546     0.085     4.882
                                                          Slope      0.149     0.234     0.146      0.142     0.013     0.255
                                                          P          <0.002   <0.002 <0.002         0.124     0.940     <0.002

                          Pamlico River Estuary Water Quality Trends                                                         63

                          Table 4.3. continued

                                                                               River Segments and Time Intervals

                                                                            1967-1986                      1975-1986

                          Parameter                                    B        E         H           B        E         H

                          Total Dissolved P               z          5.723     4.644    5.156       2.487    0.327      2.917
                                                          Slope      0.115     0.222    0.112       0.198    0.061      0.213
                                                          P          <0.002    <0.002   <0.002      0.013    0.741      0.004

                          Ammonia Nitrogen                z          -5.512    -5.357   -6.131      -1.642   -1.073     -2.003
                                                          Slope      -0.303    -0.250   -0.228      -0.179   -0.100     -0.233
                                                          P          <0.002    <0.002   <0.002      0.101    0.285      0.046

                          Nitrate Nitrogen                z          -2.813    1.327    3.010       0.062    0.838      -0.333
                                                          Slope      -0.280    -0.019   0.026       0.005    0.015      -0.017
                                                          P          0.005     0.187    0.003       0.522    0.407      0.741

                          Total Nitrogen                  z          4.721     4.536    2.871       2.618    2.923      0.238
                                                          Slope      1.547     1.356    0.845       1.664    1.807      0.150
                                                          P          <0.002    <0.002   0.004       0.009    0.004      0.818

                          Total Dissolved N               z          1.169     1.467    0.183       1.385    1.488      -1.059
                                                          Slope      0.260     0.292    0.040       0.450    0.619      -0.709
                                                          P          0.242     0.142    0.857       0.168    0.136      0.289

                          Chlorophyll A                   z          2.648     -1.398   -1.293      3.218    2.937      -0.034
                                                          Slope      0.294     -0.156   -0.140      0.635    0.451      -0.004
                                                          P          0.008     0.165    0.197      <0.002    0.003      0.976

                             Seasonal salinity patterns in the                    There are also interannual variations
                          Pamlico are affected mainly by variation in          in salinity which become obvious only when
                          freshwater runoff (Copeland and Hobbie               data from a number of years are compared
                          1972; Stanley 1986). Typically, salinity is          (Figure 4.8). For example, 1967-1970,
                          lowest during the late winter and early              1976-1977,1981,1985 and 1986 were rela-
                          spring when freshwater inflow is highest             tively high salinityyears, while 1978-1979
                          (Figure 4.7). The salinity increases to              and 1983-1984 were low salinity years. In
                          maximum values during the summer and                 some periods, the salinity graduallytrended
                          fall, coincident with lowest river flow. In          downward (1968-1971) or upward (1983-
                          some years this seasonal pattern may be              1986), but in other instances, the change
                          upset by unusually high or low freshwater            was more abrupt. For example, between
                          inflow associated with hurricanes orperiods          the 1979-1980 winter and the 1980-1981
                          of drought. Examples of such events are              winter, the mean salinity appears to have
                          given in descriptions ofdata from individual         increased about 8 ppt.
                          years by Hobbie (1974) and Stanley (1986a,              The Seasonal Kendall test indicated
                          1986b, 1987).                                        that surface salinity has increased upriver
                                                                               in segment B since 1967. The trend was

                       64                                                                            Chapter 4
                       statistically significant (p = 0.026) with a  trend in river flow which would be expected
                       slope of 0.05 ppt per year, or 0.9 ppt during if the upriver salinity is trending upward.
                       the 18-year sampling period. In the down-     On the other hand, trends in pH and nitrate
                       river segment, H, the trend was downward      nitrogen described belowcould be explained
                       but the significance level (p = .124) was not by these salinity trends. In short, no
                       quite low enough to be classified as statis-  definitive conclusions can be drawn from
                       tically significant. Salinity has not changed these data regardinga salinity trend in the
                       in the middle segment (Table 4.3).            river since 1968.
                           Bottom water salinity upriver in seg-         The Pamlico report prepared by North
                       ment B has also trended upward slightly       Carolina DNRCD (1987a) cited an analysis
                       during the past two decades. The change       by Sholar (1980), and included a time-
                       detected by the Kendall test was statis-      series salinity plot from his report, which
                       tically significant (p = 0.054) at a rate of  showed a decrease in the mean annual
                       0.07 ppt per year, or about 1.25 ppt during   salinity for the"Painlico Sound area" (sta-
                       the sampling period. Farther downriver,       tions not given) over the period 1948-1980.
                       no significant trend was detected in seg-     Comparison of Sholar's trend plot with the
                       ment E (mid-river), but a highly significant  "Mean of All Stations" plot in Figure 4.8
                       (p = 0.005) downward trend was detected       suggests to me that if Sholar's analyses
                       in segment H nearthe mouth ofthe estuary.     were extended to include the highersalinity
                       The rate ofdecrease was -0. 13 ppt per year,  years following 1980, it is likely that no
                       which amounts to 2.3 ppt, or about 15%,       overall (1948-1986) trend would be seen.
                       during the 18 year sampling interval.             The pH in estuaries is influenced by the
                           It is difficult to explain the salinity   mixing of seawater and freshwater and by
                       trend results, or to see a pattern in them.   the rates of microbial (algal and bacterial)
                       The fact that there were significant trends   respiration and algal photosynthesis in
                       for the 1968-1986 period, but none for the    the water. Freshwater typically has pH's
                       1975-1986 period, suggests that most of       lower than seawater, and the situation can
                       the change occurred between 1968 and          be complicated in estuaries like the Pamlico
                       1975. The trend upriver was positive, but     bythe inflowofwater flushed from swamps
                       downriver it was negative, and I can think    that is often quite acid (low pH) (Hobbie et
                       of no explanation for this contradiction.     al. 1972). When algal photosynthesis is
                       Also, there was no significant downward       high, the pH is also high because the algae

                           12                                                          Figure 4.7. Surface salinity
                                                                                       (ppt) in the Pamlico River
                           10
                                                                           77          estuary during 1984, as a
                                                                                       function of time (x-axis) and
                       T                                                                         -axis). Top ofplot is
                           7                                                           distance (y
                       A   7W        M MatmMAWMEWTIM                WIM
                       T   is        MARMIMEMNEUMM                  N1031hi            station 12 upriver (see Methods
                       1   6             0"MMIMM3008                UMM"               for explanation of distance
                       0   5                                                           scale).
                       N   4
                                          ARM
                                            MINH

                              i    F  M    A   M   J    J   A    S   0 N D
                                         SURFACE    SALINrrY (ppt)

                                4        2-4     4-6      6-10     19-15   3.15

                        Pamlico River Estuary Water Quality Trends                                              65

                        have removed most of the carbon dioxide       this pattern is that freshwater from the
                        and made the water basic. Respiration, on     Tar River has much higher nitrate concen-
                        the other hand, adds carbon dioxide to the    trations than does Pamlico Sound water at
                        water, thus increasing the acidity and        the other end of the estuary. But a second-
                        lowering the pH.                              ary cause is that nitrate often behaves
                           The pH in the Pamlico usually ranges       nonconservatively in the estuary. That is
                        from around 6.5 to over 8.5, but because it   to say, the decline in nitrate concentration
                        is influenced by several variables, there     in the estuary is caused by more than
                        are not very clear spatial or temporal pat-   simple dilution by seawater. Nitrate is
                        terns. About all that can be said is that it  used up (assimilated) by phytoplankton,
                        tends to be lower upriver than downriver,     which are scarce in the Tar River but
                        and it sometimes goes up during the algal     abundant in the upper estuary, and there
                        blooms that occur in the river in the late    is apparently little replacement of the
                        winter and early spring.                      assimilated nitrate. Consequently, nitrate
                           Highly significant downward trends in      concentrations usually exhibit a temporal-
                        pH (p <0.002) were detected by the Seasonal   spatial pattern in the estuary that is the
                        Kendall trend test for segments H and E       inverse of the salinity pattern, but nitrate
                        between 1975 and 1986 (Table 4.3). The        levels decrease more rapidly than salinity
                        slopes were about 0.04 pH units per year,     increases, especially in the upper end ofthe
                        which amounts to a change of 0.68 units       estuary. This accounts for the nonlinear
                        over the sampling period. The lower pH        relationship between salinity and nitrate
                        could be related to declining salinity, at    (Figure 4.9).
                        least in segment H. As explained above,           The most significant change in nitrate
                        lower salinity (i.e., increased freshwater    nitrogen in the Pamlico during the past 20
                        inflow) should lead to lower pH.              years occurred upriver, where there appar-
                                                                      ently has been a decline. The Seasonal
                        Nitrogen                                      Kendall test results indicated a highly
                           Nitrate Nitrogen: Nitrate nitrogen is      significant (p = 0.005) decrease in nitrate
                        one of the most variable nutrients in the     for river segment B (upriver) during the
                        Pamlico, but there is a seasonal pattern in   period between 1967 and 1986. But there
                        this variability. In most years, highest      was no significant change for the 1975-
                        concentrations occur upriverduringwinter,     1986 period, suggesting that the decline
                        coincident with peak Tar River flows, and     occurred during the early 1970s. The
                        lowest concentrations occur downriver         average rate of change was about 0.3 PNV
                        during the summer. The primary cause of       year, or 5.1 @Mduringthe 17-yearsampling

                           is MEAN OF AL. STAn ONS                        100
                        P  15                                              80
                        0.
                        E@, 12                                         z   60
                           9
                        z                                                  40
                           6
                           3                                               20

                           0                                                0
                           1965   1970    1975   1980   1985    1990        0       5      10     15      20     25
                                             YEAR                                        SALINITY (ppt)
                        Figure 4.8. Surface salinity (ppt) in the Parnlico Figure 4.9. Nitrate nitrogen (,@LM) versus salinity
                        River estuary, 1967-1986. Values plotted are  (ppt). Dataarefrom stations 1, 5,8, 10and 12 (1975-
                        averages of all stations 8cunpled.            1986).

                      66                                                                              Chapter 4

                      period. This change represents approxi-        offset losses from assimilation and dilution,
                      mately a 25% decrease from the 1970            and at some times of the year it is a more
                      median nitrate level. Based on the relation-   important source of ammonia than inflow-
                      ship between nitrate and salinity described    ingTar River water (Kuenzler et al. 1979).
                      above, it would be reasonable to conclude          Ammonia abundance in the estuary
                      that this decrease was due, at least in part,  appears to be trending downward at a
                      to the salinity increase detected in this      rapid rate. During the period 1967-1986,
                      segment.                                       the decline was highly significant (p< 0.002)
                         The Seasonal Kendall test indicated a       for all three river segments examined
                      highly significant (p = 0.003), but small      (Table 4.3). The average rate of decrease
                      (0.4 pM), nitrate increase downriver (seg-     was quite rapid - about 0.3 gM/year up-
                      ment H) over the 1967-1986 period. Again,      river (segment B) and around 0.23 AMI
                      this change could be explained by salinity,    year farther downriver (segment H). For
                      which was shown above to have decreased        segment B, this is equivalent to about a
                      in this segment. But this could also be        60% decline over the 17-year period of
                      simply an artifact resulting from changes      record. The decline is especially noticeable
                      in analytical sensitivities. Before 1975,      when one compares values from the early
                      nitrate levels lower than 0.1 /.LM were        1970s with those for 1984-1986. Once
                      reported frequently, but after 1980, the       again, it should be remembered that data
                      values less than 0.71 14M were reported as     from the period 1975 through the end of
                      0.71 jLM, the lower limit of detection         1979 had to be eliminated from consider-
                      (Appendix 4.3). This change in data            ation in the trend test because of the high
                      reporting probably had little effect on the    minimum detection limit associated with
                      upriver trend results, because the nitrates    the method used for the analyses in those
                      there were usually higher than 0.71 gM,        years.
                      but it may have contributed to the apparent        Total Nitrogen: Total nitrogen (TN),
                      upward trend in the downriver segment,         which consists of total dissolved nitrogen
                      H, where nitrate is much less abundant.        plus particulate nitrogen, is the most diffi-
                      The nitrate data from 1975 through 1979        cult nitrogen fraction to measure accu-
                      were omitted from the Kendall test because     rately. The problem has to do with uncer-
                      of the very high (3.57,4M) lower detection     tainties about the completeness ofthe diges-
                      limit reported during that period. In any      tion used to break down the organic con-
                      case, there has been no significant change     stituents. There have been several changes
                      in nitrate levels downriver since 1975.        in the methodology used to analyze Pamlico
                         AmmoniaNitrogen: Ammonia nitrogen           TN, and there is much uncertainty about
                      is also more abundant in Tar River water       the efficiency of some of the methods used
                      than in Pamlico Sound water, but in the        (see Appendix 4.3).
                      Pamlico River estuary, concentrations do           TN concentrations have fluctuated
                      not range as widely as nitrate concentra-      widely, and sometimes abruptly, during
                      tions. In general, they are between 1 and      the 17-year period of record (see Figure 31
                      8 ttM upriver (segment B), <0.71 pLM to 6      in Stanley 1988). However, I strongly
                      gM downriver (segment H) and inter-            suspect that much ofthis variability can be
                      mediate in the middle segments. This rela-     traced to methodological problems. For
                      tively constant pattern probably results       example, I doubt that the abrupt decline in
                      from ammonia production in the sediments       1977 and the sudden rise in 1980 are real.
                      and water associated with organic matter       There were changes in the methodologies
                      decomposition. This production tends to        at each of these times. Also, the apparent

                         Pamlico River Estuary Water Quality Trends                                                        67
                         wide fluctuations during 1975-1977 prob-               changes in biology and hydrography
                         ably are due in part to the fact that data             of the river. The very high values for
                         from this period are from three different              dissolved organic nitrogen in 1970-
                         sampling programs (Kuenzler et al., Davis              1971 (August through December)
                         et al., and ICMR), each of which used a                correlate well with the very low stream
                         different method for the TN analyses. Of               flow. On the other hand, when the
                         course, this is only speculation and unfortu-          streams started to flow again in mid-
                                                                                January there was a reduction in
                         nately there is noway to determine whether             dissolved organic nitrogen concentra-
                         or not this is the correct explanation. The            tion followed by an eventual increase
                         methods used to measure TN have been                   which may well correlate with the
                         less variable since 1980, and during this              increased biological productivity at
                         period there have not been such abrupt                 that time. During 1971-1972, the dis-
                         fluctuations as in the earlier years.                  solved organic nitrogen concentrations
                             The trend test indicated highly signif-            were very low during the heavy rains
                         icant increases in TN in all three segments            of October and November. On the
                         between 1967 and 1986 and in segments B                other hand, the high rates of flow in
                         and E between 1975 and 1986. But, as                   May seem to contain quite high
                                                                                amounts ofdissolved organic nitrogen.
                         indicated above, there are reasons to doubt            A number of hypotheses can be put
                         the validity of these results. I think the             forth as to the reason for abrupt
                         most likely explanation for the apparent               changes, such as there is a flushing
                         trends is that the digestion method used in            effect of high waters on swamps that
                         the early analyses (ultraviolet radiation),            increases the dissolved organic nitro-
                         gave less complete breakdown ofthe organic             gen in the rivers and streams. Also it
                         nitrogen than the more rigorous wet chem-              is possible that DON is being produced
                         ical digestions used later (see Appendix 4.3           during algal blooms. At this time,
                         for more details). This would explain the              however, we do not have enough infor-
                         apparent increase in the TN concentrations.            mation as to the source and fates of
                                                                                these compounds that are lumped
                         Once again, however, this is only specula-             under the name dissolved organic
                         tion, and I cannot be sure that had the                nitrogen. Certainly the biologically
                         methodology remained constant, there                   active part is very small ... Yet, these
                         would not have been an upward trend in                 compounds are still potentially impor-
                         the concentrations.                                    tant as they contain a great deal of
                             Total Dissolved Nitrogen: Total dis-               nitrogen and their total concentrations
                         solved nitrogen is not a particular chemical           are always greater than the total con-
                         form of nitrogen, but rather includes a                centrations of the dissolved inorganic
                         large number of compounds, including                   nitrogen" (Hobbie 1974, pages 73-75).
                         ammonia and nitrate, that passed through               The Seasonal Kendall test showed that
                         the glass fiber filter when the dissolved         there has been no significant change in
                         and particulate fractions are separated.          total dissolved nitrogen in the Pamlico
                         Hobbie (1974) subtracted the inorganic            (Table 4.3). However, as noted above, the
                         forms (nitrate and ammonia) from TDN to           methods used to measure TN and TDN
                         obtain estimates ofdissolved organic nitro-       have changed several times over the study
                         gen (DON), but could not explain changes          period, so this result may not be valid.
                         in the DON data:
                             ". . . The yearly cycle of the dissolved      Phosphorus
                             organic nitrogen concentration is also             Concentrations of all three forms of
                             difficult to interpret in terms of known      phosphorus measured in the Pamlico

                      68                                                                                    Chapter 4
                      samples (total phosphorus [TP1, total dis-          topic in every Pamlico report he prepared.
                      solved phosphorus [TDP], and orthophos-             In a 1971 report, he made these comments:
                      phate phosphorus [OP]) are generally high-
                      er in the summer than in the winter. For                    Earlystudies centered around the
                      example, in 1984, dissolved orthophosphate              possible effects that the establishment
                      concentrations were often >2 pM during                  of a phosphate mine on the south side
                      the summer and fall, and less than 2 gm                 of the river (Texas Gulf Sulfur Corp.)
                      during the winter. Both TDP and TP fol-                 would have on the water chemistry
                                                                              andbiology. It is nowapparent(Hobbie
                      lowed the same temporal pattern as OP.                  1970a) that there is enough phosphorus
                      TDP ranged from around 2- 10 I.LM in winter             naturally present in the river and that
                      samples to 10-20 1AM in summer samples.                 the phosphorus added from the phos-
                      TP was only slightly higher, indicating                 phate mine operations has no added
                      that particulate phosphorus makes up a                  effect on the biology."
                      relatively small fraction of the total P in                 "The natural levels of P in the
                      the estuary.                                            estuary are in the 1-2 jkg-at P/liter
                           Nixon (1983) noted that this summer                range (1 gg-at P equals 31 @Lg) for
                      increase in phosphorus is a feature common              [orthophosphate phosphorus]. As a
                      to many estuaries, and he discussed several             result of the mining activities, levels
                      possible explanations, but concluded that               as high as 93 pg-at/liter have been
                                                                              measured. However, the release is
                      no single factor can explain the pattern in             intermittent and the higher phos-
                      all the estuaries. Judging from the informa-            phorus water is found as patches that
                      tion presented in Nixon's discussion, and               move seaward along the south shore of
                      other available information, I suspect that             the estuary. Because of removal of
                      two factors are important in the Pamlico.               phosphorus by the sediments, removal
                      The first is increased bottom water hypoxia             by microorganisms, and dispersion
                      in the summer. As shown by Kuenzler et                  dilution, the patches of high phos-
                      al. (1984) for the Pamlico River, and by                phorus water do not reach Pamlico
                      similar studies for many other estuaries                Sound. There does appear to be, how-
                      (e.g., TaftandTaylor [1976] forChesapeake               ever, an increase over the past three or
                                                                              fouryears in the concentration ofphos-
                      Bay), this hypoxia increases the release of             phorus entering the estuary in the
                      phosphate from the sediments. Second,                   river water. This may be the result of
                      Tar River flowdecreases in the summer, so               increased sewage treatment and of
                      that there is less dilution ofthe phosphorus-           increased use of detergents" (Hobbie
                      rich Texasgulfeffluent and s lower flushing             1971, pages 5-8).
                      of the discharge from the estuary.                      In another report (Copeland and Hobbie
                           There is also spatial variability in the       1972) summarizing the 1967-1969 sam-
                      phosphorus -levels that usually follows a           pling, three conclusions were given regard-
                      pattern. Highest concentrations are found           ing phosphorus in the estuary: 1) there
                      in the middle section-of the river, especially      had been a tripling of total phosphorus
                      adjacent to the Texasgulf discharge, with           levels in the upper river, 2) the middle
                      intermediate concentrations upriver and             river was greatly affected by the high con-
                      lowest concentrations at the outer end of
                      the estuary near Pamlico Sound.                     centrations of total phosphorus entering
                           For obvious reasons, there has always          from Texas Gulf Sulfur, and 3) the lower
                      been a great deal of interest in trends in          section ofthe river also seemed to be strongly
                      phosphorus in the Pamlico, so it is not             affected by Texas Gulf Sulphur's activities.
                      surprising that Hobbie wrote about this

                          Pamlico River Estuary Water Quality Trends                                                         69
                              Finally, after his monitoring program           there were also increases in TDP in seg-
                          ended in 1973, Hobbie had this to say               ments H and B, but not in the middle river
                          about the 1971-1973 phosphorus data:                segment, E. Orthophosphate increased in
                                                                              segments H and E between 1967 and 1986,
                                   It is interesting to remember the          but only in the downriver segment, H,
                              increase of phosphorus in the upper             since 1975. The average annual rate of
                              stations and the entire river that were         increase varied from 0.04 AM/year to about
                              seen over the first four or five years of       0.086/.kl%Vyear. For the downriver segment,
                              phosphorus measurements. Although               H, these rates translate to an overall in-
                              high amounts of phosphorus are still
                              seen in the upper parts ofthe river, the        crease of about 0.7 AM since 1967.
                              increase does not appear to have con-               The fact that phosphorus abundance
                              tinued past 1970 or so" (Hobbie 1974,           has not changed in the mid-river segment
                              page 50).                                       since 1975 probably is a reflection ofdeclin-
                                                                              ing P loading from Texasgulf, counter-
                              Results of the Seasonal Kendall tests           balanced, to some extent, by increased
                          seem to confirm Hobbie's observation that           loading from the Tar River. Monthly load-
                          phosphorus was increasing in the river in           ing of P (in tonnes) from the plant site has
                          the late 1960s. The increase in TP was              decreased by about two-thirds since the
                          shown to be highly significant (p<0.002) in         mid-1970s (Figure 4.10). It would seem
                          all three river segments examined for the           that this large reduction ought to have
                          time period 1967-1986 (Table 4.3). The              produced a significant downward trend in
                          average rate of increase at the middle              phosphate in the river, given that the
                          segment, E, was 0.23 AM/year, or about 4.4          Texasgulf discharge accounts for approxi-
                          AM over the 19-year sampling period. This           mately 40% of the total P loading to the
                          amounts to approximately a doubling of              river (North Carolina DNRCD 1987). But,
                          the 1967 TP levels. In the upriver and              the decreased TG load probably has been
                          downriver segments, B and H, the TP levels          offset to some extent by increased loading
                          trended upward at about half this rate.             from the Tar River, so that the overall
                          However, when only the period 1975-1986             pattern is one of little change since 1975.
                          was examined, it was found that there was           Unfortunately, there are no historical Tar
                          a significant increase in TP only downriver         River loading data which could be used to
                          in segment H (p<0.002). But the average             test this hypothesis.
                          annual rate of increase in this segment
                          since 1975 has been 0.25 AM/year, nearly            Nutrient Limitcytion in the Pamlico
                          twice the rate over the longer period.                  Nitrogen-to-phosphorus ratios are often
                              Total dissolved phosphorus and ortho-           computed for aquatic ecosystems to indicate
                          phosphate phosphorus have also increased            which of the two nutrients is most likely to
                          signif icantly, particularly in the lowerestu-      be limiting to phytoplankton growth. The
                          ary. The trend test results are about the           ratios can be calculated several ways, but
                          same as for TP, which is not surprising             most often they are made by dividing the
                          since OP and TDP are the major fractions            water-column concentrations of total dis-
                          comprising TP. For TDP, the increases               solved inorganic nitrogen (DIN) by the con-
                          between 1967 and 1986 were highly signif-           centration of orthophosphate phosphorus
                          icant (p<0.002 for all three segments), and         (OP). The significance of this ratio stems
                          the rate of increase was highest in the             from the fact that algal production is deter-
                          middle segment (Table 4.3). During the              mined in part by the need for nitrogen and
                          more recent sampling period, 1975-1986,             phosphorus in proportions (atomic) of 16:1,

                         70                                                                                                 Chapter 4

                         respectively (Redfield 1934). Water-column                 ity in algal composition ratios, and hence it
                         DIN:OP ratios less than the "Redfield Ratio"               is probably more realistic to view
                         indicate that nitrogen is less abundant                    composition ratios as ranging from around
                         than phosphorus relative to the phytoplank-                10:1 to 20:1 (Boynton et al. 1982).
                         ton's need. On the other hand, values                          Calculated ratios of water column
                         higher than 16:1 indicate that phosphorus                  DIN:OP suggest that nitrogen is more likely
                         is less abundant. Thus, ifthe phytoplankton                than phosphorus to be limiting upriver in
                         continue to grow and there is no N or P                    the Pamlico during the summer and down-
                         replenishment in the water, one nutrient                   river at all times of the year. Figures 4. 11-
                         will be exhausted (i.e., become "limiting'l                4.13 give the ratios at five stations along
                         before the other, depending on the ratio.                  the salinity gradient 'between 1979 and
                         Studies by Parsons et al. (1961) and Rhee                  1986. In the lower half of the estuary
                         (1978) indicated that there is some variabil-              (stations 1 and 5), DIN:OP ratios are almost
                           W                                                        always less than the ideal Redfield ratio
                           0     150                                                (16: 1), or the 10: 1-20:1 range of N:P ratios
                           ;;z -
                              F_ 120                                                normally found in algal cells. Upriver, the
                              Z
                           00    90                                                 ratios increase, more because of increasing
                           0
                           a.
                           @3 W  60                                                 DIN (principally nitrate), rather than
                           M z         k@
                              z                                                     decreasing phosphate. There is also a
                                 30                          AA1*4                  strong seasonal pattern in the ratios at all
                                    01            -
                                    1973        1978          1983           19M    stations. This pattern is determined prima-
                                                      YEAR                          rily by the nitrate levels, which vary more
                                                                                    than either ammonia or nitrate over the
                         Figure     4.10. Texasgulf phosphorus discharge            course ofthe year. Figure 4.14 more clearly
                         (tonnes), by month, 1974-1986.

                               100  STA11ON 1                                             1000  STATION 8
                                                                                           100
                           a.  10                                                     a.
                                                                                      0
                                                                                            10 -

                               0.1                                                         0.1
                                 80     81    82    83     84    85    86      87             80    81     82    83    84     85    86    87

                                                      YEAR                                                        YEAR
                               100   TATION 5                                             1000  STATION 10
                                                                                           100
                           a. 10                                                      CL
                                                                                             10

                               0.11                                                        0.1
                                 80     al    82     83    84    85     86     87             80    81     82    83    84     85    86    87
                                                      YEAR                                                        YEAR
                         Figure 4.11. Ratio of total dissolved inorganic            Figure 4.12. Ratio of total dissolved inorganic
                         nitrogen (DIN) to orthophosphatephosphorus (OP)            nitrogen (DIN) to orthophosphatephosphorus (OP)
                         in the Pamlico River estuary, 1979-1986. (A)station        in the Pamlico Riverestuary, 1979-1986. Wstation
                         1, (B) station 5.                                          8, (B) station 10.

                          Pamlico River Estuary Water Quality Trends                                                     71
                          shows the decline in the N:P ratio with           there were no statistically significant trends
                          increasing salinity. Most instances of N:P        in the concentrations, but the percent satu-
                          higher than 16:1 occur upriver in the winter      ration data did show a significant down-
                          months when river flows, and hence nitrate        ward trend in segment H (Table 4.3). The
                          levels, are highest. Similar results for          annual average percent saturation declined
                          other estuaries are discussed later in this       from about 70% to 60% over 18 years.
                          report.                                           There was no significant trend in the seg-
                              It is very important to realize that          ment B and segment E data. Dissolved
                          these N:P ratios are only evidence for pos-       oxygen dynamics in the Pamlico River are
                          sible N or P limitation, not proof that such      described in more detail in Chapter 5.
                          limitation exists. Phytoplankton must con-
                          sume the nutrients faster than they are           Chlorophyll a
                          resupplied, from either internal recycling           Chlorophyll a is a reliable indicator of
                          or outside input, in order for one or the         algal biomass that has been monitored in
                          other to become limiting. In fact, other          the Pamlico since 1970. The most impor-
                          factors, such as light or temperature, often      tant findings from this sampling are that
                          control algal growth to such an extent that       blooms of algae occur each late winter or
                          the nutrients are not exhausted. In these         early spring, but the median chlorophyll a
                          circumstances, the N:P ratio has no influ-        levels peak in the summer months. The
                          ence on the growth. In other words, both          winter blooms occur in the middle reaches
                          the absolute and the relative N and P
                          concentrations must be considered (along
                          with the resupply rate!) when one specu-               1000  TATI ON 12
                          lates on algal nutrient limitation. The                 100
                          importance of limitation by factors other           a-
                                                                              0
                          than nutrients is often overlooked in the                  10
                          heat of debate associated with the long-            Q
                          running N vs. P limitation controversy.                    1
                          But given the high turbidity, particularly              0.1
                          upriver in winter (Kuenzler et al. 1979),                  80  81    82   83   84    85   86     87
                          and the wide temperature fluctuations that                                 YEAR
                          characterize estuaries like the Pamlico,          Figure 4.13.  Ratio of total dissolved inorganic
                          these factors probably override nutrient          nitrogen (DIN) to orthophosphatephosphorus (OP)
                          influences, at least during some parts of         in the Pamlico River estuary, 1979-1986, at station
                          the year.                                         12.

                          Dissolved Oxygen                                       100
                             The trend test (Table 4.3) showed a
                                                                                  10                  t
                          highly significant (p<0.002) upward trend           IL               %
                          in surface water dissolved oxygen for all           O@     1
                          three river segments tested. The estimated                          A  I
                                                                                  0.1
                          slopes were 0.05-0.08 mg/liter per year,
                          which amounts to an increase of 0.9-1.4 mg             0.01
                          02/liter, or approximately 10%, over the                   0       5        10       15         20
                          18-year period of record. The reasons for                              SALINITY (ppt)
                          this apparent increase are unknown.               Figure 4.14. DIN. OP ratio versus salinity in the
                             For bottom water dissolved oxygen,             Pamlico River estuary, 1979-1986. Data from
                                                                            stations 1, 5, 8, 10 and 12.

                       72                                                                                    Chapter 4
                       of the estuary (Stanley 1987; Hobbie 1974).            For the mid-river segment, E, there
                       Two other features of the blooms are that          was no significant change in chlorophyll a
                       theyare short-lived, and they usually occur        over the whole samplingperiod, 1970-1986.
                       at only one or two sampling stations. Also,        But when the shorter period 1975-1986
                       river flow can play an important role in the       was tested, a significant increase (p = 0.003)
                       timing and location of the winter blooms.          was detected. In other words, chlorophyll
                       In some years, high water inflow from the          apparently declined in this river segment
                       Tar flushes out much ofthe algal population        duringthe 1970s, and then increased again
                       from the river.                                    in the 1980s. The time-series plot (Figure
                          The trend test results indicate that            51 in Stanley 1988) for this segment clearly
                       chlorophyll a concentrations have increased        shows the decrease from concentrations
                       in the middle and upper segments, B and            typically between 10 and 20 jig/liter in the
                       E, of the Pamlico, but not in the downriver        early 1970s to often < 10 jkg/liter in the mid-
                       segment, H. Upriver in segment B, the              1970s. Of course, these data are from
                       increase was highly significant (p<0.01),          different sampling programs, but I could
                       during both time intervals tested. The             find no evidence ofchanges in the analytical
                       average annual rates of increase were 0.29         techniques that could explain the differ-
                       ;kg/liter per year and 0.64 /ig/liter per year     ences. Therefore, I must assume that the
                       for 1967-1986 and 1975-1986, respectively.         decline was real.
                       This is equivalent to about a 50 percent               A very noticeable feature of the chloro-
                       increase duringthe 16-year period ofrecord.        phyll time-series plots is that in recent
                                                                          years the bloom peaks appear to be more
                                                                          frequent and higher, particularly upriver
                                                                          in segment B. But closer examination
                             25  A                                        showed no clear long-term trend in the
                             20               DECEMBER-MARCH              frequency of high values. I made a plot of
                             15                                           the percentage ofvalues over 40 gg/liter for
                                                                           ach year since the sampling began in
                                                 VEMBE
                        (L   10                  0    R                   e
                        <                  7
                              5
                                                                          1970 (Figure 4.15). Note that there were
                                                                          no data for 1974, and the 1985 data were
                              01970        1975       1980        1985    not used because some of them are suspect.
                                                 YEAR                     In 1979, the North Carolina Environmental
                                                                          Management Commission adopted a chlo-
                             30  B                                        rophyll a quality standard of 40 gg/liter for
                             25            LOWER             UPPER             all lakes, sounds, estuaries, reservoirs
                             20
                                                                          and other slow-moving waters not desig-
                                             MIDDLE                       nated as trout waters" (North Carolina
                             10                                           Department ofNatural Resources and Com-
                              5
                              0                                           mun ity Development 1987, page 38). This
                               1970        1975       1980       1985     standard applies during the months April
                                                 YEAR                     through November. In most years, the
                                                                          highest number ofPamlico samples exceed-
                       Figure 4.15. Pamlico River estuary chlorophyll a.  ing4O pg/liter occurred in the wintermonths
                       Percentage of sample values greater than 40 AgI    of December through March, when the
                       liter for eachyear (1970-1986). (A)Datagroupedby   standard is not applicable (Figure 4.15a).
                       twoperiods (April-November andDecember-March).
                       (B) Data grouped by river segment: "upper" =       The percentage ofApril-November samples
                       segments A, Band W@niddle"= segments D, E and      violating the standard has ranged from
                                       PM
                                oil

                       F, "lower" = segments G, H and L

                              Pamlico River Estuary Water Quality Trends                                                                  73

                              <1% in 1970, 1975-1976 and 1980, to                     5-10. Farther downriver in the middle
                              around 10% in 1986. There has been no                   reach (segments D, E and F), the percent-
                              clear trend in these percentages. Overall               ages were about the same, but in the lower
                              the early 1970s values are about the same               river (segments G-I), no more than 6% of
                              as those for the early-to-mid 1980s. The dip            the samples had over 40 lig chlorophyll a/
                              in the mid-1970s maybe real, ormaybe an                 liter in anyyear. Again, there has been no
                              artifact associated with the relatively infre           obvious change in this pattern since the
                              quent late winter sampling between 1975                 sampling was begun in 1970.
                              and 1979.
                                  Inmost years, high chlorophyll a values             Phytoplankton Species Composition
                              were more frequent in the upper and middle              and Biomass
                              river areas than in the lower estuary                        Phytoplankton have not been moni-
                              (Figure4.15b). In the upper area - encom-               tored regularly for a long period in the
                              passing river segments A, B and C -up to                Pamlico River. Therefore, there are not
                              24% of the values were >40 /ig/liter (1986).            sufficient data to permit analysis of trends
                              More typically, the percentage was around               by the Seasonal Kendall procedure. How-

                                                                             A
                                                                          100 -
                              Figure 4.16. Phytoplankton
                              biomass (averaged by sampling               so -                                          X
                                                                                                               X
                              date) in the Pamlico River for (A)
                              1966-1968 and (B) 1983-1985.
                              Wet weight (mg1liter) for each
                              cla8s expressed aspercent oftotal                            DIN                             I    X:
                                                                          so -
                              biomos8. BAC = Bacillario-
                              phyceae, CHL = Chlorophyceae,               ao -
                              CHR = Chry8ophyceae, black
                              Cyanophyceae, DIN = Dino-                   40 -
                              phyceae, UNK      Unknown.                  30-                tt- nt

                                                                          20-

                                                                          0
                                                                                   1966                  1967                     1968
                                                                             B
                                                                          100

                                                                                                                       UNK

                                                                          70

                                                                          50-

                                                                          40 -                           CHL

                                                                          30 -

                                                                          20

                                                                                                                          .... . ..   ........
                                                                                   1983                  1984                  1985

                    74                                                                              Chapter 4

                    ever, there have been two major studies of      the same ones used for the nutrient and
                    phytoplankton species, numbers and bio-         hydrography study.
                    mass in the Pamlico. Since these studies            The data suggest that phytoplankton
                    were separated by a time interval ofapprox-     species composition in the Pamlico has not
                    imately 15 years, I thought it might be         changed substantially during the past two
                    useful to compare the results, which might      decades. Figure 4.16 shows phytoplankton
                    at least give clues about the presence or       biomass broken down by class, for both the
                    absence of long-term changes in the estu-       1966-1968 samples and the 1983-1983 sam-
                    ary's phytoplankton. The first study was        ples. The plotted data are means of all
                    by Hobbie (197 1) for the time period August    stations sampled on each date. In both
                    1966 through April 1968. Samples came           sample periods, four classes made up the
                    from the same stations used for nutrient        bulk of the total biomass. These were
                    and hydrographic monitoring. The second         diatoms (Class Bacillariophyceae), green
                    phytoplankton study, sponsored by North         algae (Class Chlorophyceae), chrysophytes,
                    Carolina Phosphate Corporation, was made        (Class Chrysophyceae), and dinoflagellates
                    during the period April 1982 through            (Class Dinophyceae). Diatoms usually com-
                    December 1985 (Stanley 1983, 1984a;             prised around 10-20% of the total biomass,
                    Stanley and Daniel 1985a, 1985b, 1986).         although there is considerable scatter, as
                    Samples were collected approximately            there also is for each of the other algal
                    every other week from stations in the river     classes. Diatoms were most important in
                    and in South Creek. River stations were         the winter and spring. The green algae
                                                                    were also relatively important in the spring,
                                                                    comprising, on average, 58% and 17% of
                                                                    the total biomass in 1983 and 1984, respec-
                          10                                        tively (Stanley and Daniel 1985b). At
                          9 A
                                                                    other times of the year in 1983 and 1984,
                          8                                         and in all of 1966-1968, they were an
                          7                                         insignificant part ofthe total. The seasonal
                      z
                      W   6                                         pattern for the chrysophytes is clearer;
                      0
                      (9  5                                         they definitely were more abundant in the
                          4                                         summer than at other times, both during
                          19W         1967        1968        1969  the 1966-1968 and 1983-1985 sampling
                                           YEAR                     periods. In some instances, they averaged
                          8                                         70-90% of the total biomass. Overall, the
                            B                                       most abundant algal class was the dino-
                          7
                                                                    flagellates, which made up 80% or more of
                          6                           %     %       the total on many dates, particularly in the
                                                 6M %
                      z   5                                         fall and winter.
                                                                       From the data presented in Figure
                          4
                          3                                    1    4.17, it would appear that algal cell density
                          1983       1984        1985          1986 and biomass (data not shown) were sub-
                                           YEAR                     stantially higher in the late 1960s than
                    Figure 4.17. Averagephytoplankton      de       now. Between 1966 and 1968, the cell
                                                       cell ns'ty   densities (averaged on each sample date
                    (logcell8 Iliter) in the Pamlico Riverestuary during
                    two 8amplingperiods. (A) 1966-1968 and (B) 1983- for all stations) were mostly between    107
                    1985.                                           and 1011 ceils/liter, which was 10- 100 times
                            B

                                                                    higher than the typical 1983-1985 cell den-

                           Pamlico River Estuary Water Quality Trends                                                            75
                           sity. Similarly, biomass in the 1966-1968            that data from different periods would be
                           period appears to have been about ten                comparable. Unfortunately, turnover in
                           times higher than in the 1983-1985 sam-              technical personnel and the tendency to
                           pling period. There is considerable scatter          conduct short-term studies make this an
                           in the data from both periods.                       unlikely solution.
                               However, there are four reasons to                    In his report on the 1966-1968 data,
                           suspect that these apparent declines in cell         Hobbie made some interesting comments
                           density and biomass are not real. First,             regarding phytoplankton and eutrophica-
                           about three-quarters of the samples col-             tion in the Pamlico:
                           lected during the 1966-1968 study were
                           from the winter when dinoflagellate blooms                     Overall, the algae indicate that
                           (Heterucapsatriquetra) are greatest. Conse-               the Pamlico River estuary is a highly
                           quently, there were a few samples with                    eutrophic body of water. Whether or
                           very high densities and biomasses which                   not it should be called polluted depends
                           greatly affected the means. If there had                  upon the definition of pollution chosen
                                                                                     and also upon someone's opinion as to
                           been more (presumably low biomass) sam-                   the state of the river before man's
                           ples from otherseasons, the average would                 activities began in the drainage basin.
                           have been considerably lower. Second, in                  Because the algae are not a menace or
                           several samples, Hobbie found extremely                   hindrance to fishing or recreation, I do
                           high numbers of a very small unidentified                 not believe the estuary is polluted.
                           alga that was less than 2 gnis in volume.                 The natural fauna are still present
                           This species contributed nothing to the                   and so far the algae are the only indi-
                           biomass but considerably increased the                    cator showing pollution. Of course,
                           average cell density. Third, a check of the               any more nutrient enrichment should
                           cell volumes assigned to some of the most                 be avoided as the next step may be
                                                                                     deoxygenation of the water. This de-
                           abundant species showed that Hobbie's                     oxygenation would undoubtedly kill
                           estimates were, in some cases, higher than                many fish and shellfish. Although it is
                           those used in the more recent study. For                  just speculation at this point, it is very
                           example, Hobbie estimated the volume for                  likely that if the algae bloom occurred
                           Heterocapsa triquetra as 3360 jzms, com-                  during the summer months, the in-
                           pared to 2011 /-tm-1 by Stanley and Daniel                creased respiration associated with the
                           (1985a). And finally, the trend in chloro-                higher water temperature might well
                           phyll a in the river over the past two                    reduce the oxygen to a low level. For
                           decades contradicts these phytoplankton                   this reason, it is important to under-
                           biomass results.                                          stand how the phytoplankton are
                                                                                     operating and to avoid any changes to
                               It is unfortunate that the algal biomass              the estuary regime that would create
                           data are not comparable, but perhaps there                an algal bloom in summer" (Hobbie
                           is a lesson to be learned from this attempt.              1971, page 35).
                           It would seem that estimating algal cell
                           density and biomass is an "art" as much as                Some comments should also be made
                           a "science," because of the difficulty asso-         regarding blue-green algae in the Pamlico,
                           ciated with identifyingthe extremely small           since blooms of these nuisance algae have
                           forms that make up so much of the phyto-             become common in some areas of coastal
                           plankton. Perhaps the only solution is to            North Carolina in recent years. In particu-
                           have one person commit himself or herself            lar, the lower Chowan River and the lower
                           to making counts for an estuary over a long          Neuse River experience severe blue-green
                           period of time. This would at least insure           algae blooms during some, but not all,
                           internal consistency in the time series so

                    76                                                                             Chapter 4
                    summers (North Carolina Department of           lies in the difficulty, alluded to above, of
                    Natural Resources and Community Devel-          correctly identifying these tiny algae. Most
                    opment 1982; Christian et al. 1988). First,     are less than 2 Pm in diameter, so that they
                    it should be noted that the blooms in these     appear as tiny dots under the 40OX mag-
                    two systems have been restricted to fresh       nification used to make the cell counts.
                    waters, or waters of very low salinity. The     One person may count these as algae,
                    comparable region in the Tar-Pamlico            while another might disregard them as
                    would be upstream of Washington (i.e.,          pollen grains or other non-algal items.
                    upriver from station 12 used for the Texas-     This is certainly possible, but there is no
                    gulf monitoring program). Although no           way to know if this actually happened.
                    sampling for algae has been done in that           Whether or not blue-green algae are
                    area, it is probably safe to assume that no     present in the Pamlico estuary, it is clear
                    blooms have occurred there of the magni-        from both the 1966-1968 and 1983-1983
                    tude and spatial extent comparable to those     studies that they do not contribute signifi-
                    in the Chowan and Neuse. Hobbie (1971)          cantly to the total algal biomass. Using
                    apparently found blue-greens to be numeri-      Hobbie's raw data, I calculated that the
                    cally abundant at some times in the Pamlico     blue-greens usually made up less than
                    River estuary, but Stanley and Daniel           10% of the total biomass in the late 1960s.
                    (1985b) did not find them in large numbers      Similarly, duringthe more recent sampling
                    in the more recent study. It is possible that   period (1983-1985), there were only a few
                    this discrepancy represents a change in         species of blue-green algae and they
                    the river's algal species composition, but I    accounted for less than 1% of the algal
                    suspect that the more likely explanation        density and biomass in the river (Stanley
                                                                    and Daniel 1985).

                          CHAPTER5
                          Stratification and Bottom Water
                          Hypoxia in the Pamlico River Estuary*

                          Introduction                                        "One of the things we can do is to look at
                              The severity of dissolved oxygen (DO)           places like the Chesapeake Bay, the
                          depletion in the bottom waters of estuaries         Hudson River and the San Francisco Bay.
                          appears to range widely, depending on a             They were showing the same signs of stress
                          combination of factors includingmorphom-            about 10 years ago that the Pamlico is
                          etry, vertical density stratification, and          showing now . . . the signals are there.
                          perhaps nutrient and organic matter in-                                  B.J. Copeland (1987)
                          puts. Persistent bottom-water hypoxia is        obvious need for better description and
                          common in stratified estuaries that have
                          deep channels. Examples include Chesa-          quantification of the roles of freshwater
                          peake Bay and some of its tributaries (Taft     discharge, lunar tides, and winds as physi-
                          et al. 1980; Officer et al. 1984; Kuo and       cal energy inputs influencing vertical mix-
                          Neilson 1987; Kuo et al. 1991) and parts of     ing. But so far, only a few such studies
                          the Puget Sound System (Christensen and         have been made. In Chesapeake Bay,
                          Packard 1976). Coastal ocean areas such         multi-year observations and mathematical
                          as the Atlantic inner continental shelfsouth    modeling have shown that wind is respon-
                          of Long Island, NY (Swanson and Sinder-         sible for breakup of the summer stratifica-
                          mann 1979; Falkowski et al. 1980) and the       tion in the early fall and that wind-induced
                          northern Gulf of Mexico (Boesch 1983;           destratification continues through mid-
                          Harper et al. 1981) also have experienced       spring (Goodrich et al. 1987; Blumberg
                          severe hypoxia. Fortnightly mixingrelated       and Goodrich 1990). It has been determined
                          to spring-neap tidal cycles has been ob-        that for Mobile Bay - a shallow, bar-built
                          served in some estuaries, including the         estuary - the tide is less important than
                          James, Rappahannock, and York rivers            river flow and wind-driven circulation
                          (Haas 1977; D'Elia et al. 198 1; Ruzecki and    (Schroeder and Wiseman 1986; Schroeder
                          Evans 1986). In shallow estuaries wind          et al. 1990). It seems reasonable that wind
                          mixing tends to decrease water column           and river flow may strongly influence
                          stratification more frequently, so that bot-    stratification and bottom oxygen condi-
                          tom water hypoxia is generally of short         tions in many of our nation's estuaries,
                          duration and limited in spatial extent. In      given that over half have mean depths <5
                          Mobile Bay, forexample, periods ofstratif-j-    in (Nixon 1988), and that many of those
                          cation and mixing occur as frequently as        along the southern Atlantic and Gulfcoasts
                          daily (Turner et al. 1987; Schroeder et al.     are isolated from strong lunar tides by
                          1990).                                          chains of barrier islands.
                             Given that stratification is a key factor        In this paper we examine the relation-
                          in the establishment of hypoxia, there is an    ships amongbottom water oxygen, vertical
                                                                          stratification, and the factors responsible
                          *coauthored by S. W. Nixon, Graduate School of Oceanography, University ofRhode Islanc4 Narragansett,
                          Rhode Island

                    78                                                                               Chapter 5

                    for stratification-destratification in the       Banks, a chain ofbarrier islands separating
                    Pamlico River Estuary in North Carolina.         Pamlico Sound from the Atlantic Ocean.
                    The study is based primarily on a 15-year        However, "wind tides" of 0.5-1.0 m are not
                    set of biweekly oxygen, salinity, tempera-       uncommon, and are most likely following
                    ture, and nutrient concentration measure-        several days of sustained winds from
                    ments, but we also have incorporated some        directions approximately parallel to the
                    recent continuous monitoring results.            estuarine axis (Giese et al. 1979). Prevail-
                       The Pamlico is a shallow (2.7 m mean          ing summertime winds in the Pamlico
                    depth), oligohaline-mesohaline estuary ex-       region are from the SW and NE.
                    tending 65 km from Washington, NC, to               Seasonal salinity patterns in the estu-
                    the western edge of Pamlico Sound (Figure        ary are set primarily by variation in Tar
                    5.1). The estuary varies in width from           River flow. Typically, surface salinity is <8
                    about 0.5 km near Washington to about            ppt duringthe late winterand earlyspring.
                    6.5 km at its mouth. The Pamlico "River" is      The salinity increases to maximum values
                    actually the estuary ofthe Tar River, which      (10-15 ppt) during fall. However, there is
                    drains most of the 14,000 kM2basin area.         considerable interannual variability. Dur-
                    Total freshwater flow into the Pamlico           ingdrought years the salinitymay approach
                    typically ranges between 28 mls-1 in October     that ofPamlico Sound (20-24 ppt). Temper-
                    and 112 m3s-1 in February (Giese et al.          atures in the estuary typically range from
                    1979). Freshwater flushing times corre-          40C in January to 300C in August. Details
                    sponding to this flow range are estimated        of the hydrography and ecology of the
                    to be between 80 and 28 days. Lunar tides        estuary are given in Giese et al. (1979) and
                    in the estuary are almost negligible (7 cm),     Copeland et al. (1984).
                    due to restrictions imposed by the Outer

                                                                     NORTH
                                                                     CAROLINA

                          2

                                  a
                                                                                                  W
                                           3                                                       J 200,
                                                                                                        Tiw
                                        2
                                             USGS

                                                                          3
                                                         3         5

                                                              2
                                                                        3
                                                       TEXASGU
                                                             LF
                              N
                                                                                                     5
                                                                               2
                                                                                                                  .3
                                                                                                              6

                                                                                         2
                      0    2   4   6   8

                           KILOMETERS
                                                                                                                  2,

                    Figure 5.1. Location ofwater quality scunpling stations (10,8,5, and 1) and the U.S. Geological
                    Survey continuous monitoring station (USGS) in the Pamlico River Estuary. Depth contours in
                    M.

                          Stratification and Bottom Water Hypoxia                                                    79

                              Hypoxia, or "dead water" as it is known     concentrations read from the air-calibrated
                          locally, has become one of the most impor-      meter were corrected to ambient water
                          tant environmental issues for the Pamlico.      temperature and salinity. Measurements
                          Hypoxia in the estuary was first docu-          were made at two depths: approximately
                          mented in the late 1960s (Hobbie et al.         one-half meter below the surface and one-
                          1975), and was investigated more thor-          half meter above the bottom. These will be
                          oughly in the mid- 1970s (Davis et al. 1978),   referred to as "surface" and "bottom" read-
                          but knowledge about it seems to have            ings. Samples for chlorophyll a, and N and
                          become widespread only in more recent           P were collected only at the surface. Chlo-
                          times. A recurring theme in many news-          rophyll a was measured by the method of
                          paper articles, regulatory agency docu-         Strickland and Parsons (1972), and the N
                          ments, and some of the scientific literature    and P analyses were by methods given in
                          written during the late 1980s is that nutri-    USEPA (1979) and APHA (1985).
                          ent inputs promote large blooms of phyto-          In addition, we will present excerpts
                          plankton that eventually die, decompose,        from a time-series (3-hr measurement inter-
                          andcontribute inamajorwayto lowoxygen           val) of near-surface and near-bottom DO,
                          conditions during summer. In addition,          temperature, and salinity (determined from
                          most fish kills in the estuary in recent        temperature and specific conductance mea-
                          years have been attributed to hypoxia in        surements). The data are from a study
                          the bottom waters. Many citizens, and           carried out by the U.S. Geological Survey,
                          some scientists, suspect that bottom water      using a Minimonitor, a U.S.G.S. designed
                          anoxia and fish kills are more common in        instrument controlled by a CR10 micro-
                          the estuary now than in the past.               logger with data storage in an SM-192,
                                                                          which has permanent memory. The moni-
                          Methods                                         tor was mounted on the piling supporting
                              Most of the data used in this study are     Pamlico River Light 5 (a U.S. Coast Guard
                          from an ongoing water quality monitorin         navigation channel marker) about halfway
                          program sponsored by Texasgulf Che @            between our stations 5 and 8 (Figure 5.1).
                                                                    mi-
                          cals, Inc. and carried out by East Carolina     The near-bottom. and near-surface probes
                          University since 1975. Salinity, tempera-       were 1.2 in and 3.6 in above streambed,
                          ture, dissolved oxygen, NO.,-N, NH  4-N, PO 4-  respectively. Mean low water depth at this
                          P, and chlorophyll a are among the suite of     marker is estimated to be 4.5 in. The
                          variables measured approximately every          Minimonitor was serviced at 2-week inter-
                          other week at 20 sampling stations in the       vals. Vertical profiles of temperature, spe-
                          Pamlico. For this study we chose to use         cific conductance, and Do were measured
                          data from four of these stations; they are      and compared to monitor readings. After
                          all located near mid-channel along the axis     the probes were cleaned, monitor and field
                          of the estuary. Station 1 is near the mouth     readings were again compared. If the field
                          at Pamlico Sound, and Stations 5,8, and 10      and monitor readings differed only by a
                          are progressively farther toward the head       relatively small amount, the monitor was
                          of the estuary (Figure 5.1). Mean low tide      adjusted to agree with field readings. If the
                          water depths are approximately 5.0 in, 4.5      difference between the monitor and field
                          m, 4.5 in, and 3.5 in, respectively. Tempera-   readings was large, probes or the entire
                          ture and salinity were measured with a          monitor were replaced with a laboratory-
                          YSI Model 33 S-C-T meter, and dissolved         calibrated unit. The monitor was returned
                          oxygen was measured with a YSI Model 51         to the laboratory for routine recalibration
                          oxygen meter and electrode. Oxygen              at 3-month intervals (Bales 1990).

                              80                                                                                                                      Chapter 5

                                   Wind velocity data, provided by Texas-                            freshwater drainage into the estuary is
                              gulf Chemicals, Inc., were recorded at their                           proportional to the gauged flow (Giese et
                              plant site about midway down the estuary                               al. 1979).
                              on the south shore (Figure 5.1). Wind                                         We used the Spearman Rank Correla-
                              speeds were converted to stress using the                              tion procedure to investigate relationships
                              quadratic law with a drag coefficient of 1.5                           among the hydrographic variables. This is
                              x 10-8 (Garratt 1977). Daily mean Tar                                  a nonparametric test of the presence or
                              River discharge data are' from the U.S.                                absence of association between two vari-
                              Geological Survey gage at Tarboro, NC,                                 ables. It can also estimate the strength of
                              which is 80 km upstream from the estuary;                              the relationship, if one exists (Conover
                              consequently there can be substantial                                  1980; Daniel 1978). The computed coeffi-
                              travel time lags between it and the estu-                              cient (R) will range between -1 (perfect
                              arine sampling stations. Aboutone-halfof                               inverse relationship) and + 1 (perfect direct
                              the drainage basin is ungauged, but pre-                               relationship). The Spearman test is in-
                              cipitation rates and runoffgrates are similar
                              to those in the gauged areas, so that total
                                                                                                         100-

                                                                                                                       60-% SAT.
                                                                                                       80-
                                                                                                                       40-60% SAT.
                              80.      4-5 MG/1                                                    A            so-           2040% SAT
                              60       3-4 MG/1                                                                       0-20% SAT.
                              4O-
                              20                                                                          40
                                            2-3 Mg/l
                              FREQUENCY (%OF SAMPLES)
                              p 40-        1-2 Mg/l                                                      20
                                           .1mg/10

                              20                                                                        0
                                                                                                                 0-5      5-10     10-15     15-20     20-25      25
                              0
                                                                                                                                    PERATURE(06

                                                                                                                               uency of four DO percent
                                      J F  M A M J J A S O N D                      F6       Figure        5.3.  Freq
                                                             MONTH                                   saturation ranges for six temperature ranges.
                                                                                                     Includes all data from fourmonitoring stations
                                                                                                     for the period 1975-89.
                                140-
                                120-           <20 96           20-40 %          40-60 %    B            8O
                                100.           60-80%          80-100 %                             70            0-20% SATURATION

                              U. 80.                                                                 AL
                              60                                                                      60

                                                                                                         50.
                               40

                                                                                                        40-
                              20

                                                                                                       30
                               0
                                      J F M A M J J A S 0 N D
                                                              MONTH                                      10-

                              Figure 5.2. Frequency of five DO concen-                                         0-1        1-2       2-3       34         4-6       >5
                                                                                                                                   DELTA SIGMA-T
                              tration ranges (A) and percent saturation                              Figure 5.4. Frequency of Sample8 with <20%
                              ranges (B) for each month. All data from four                          DO saturation for six delta SigmaT ranges.
                              monitoring stations for the -period 197326-89                            Includes only measurements made when water
                              included.
                                                                                                     temperature was >150C.

                          Stratification and Bottom Water Hypoxia                                                      81

                          eluded in SYSTAT, a statistics package           was considered to show statistical
                          available for microcomputers. We imple-          significance.
                          mented Version 4.0 of SYSTAT, which is
                          documented in the user's manual byWilkin-        Results and Discussion
                          son (1988), on a microcomputer.                  Seosonal and Spatial Variabillty
                             The Seasonal Kendall-Tau test was                  Frequency distribution plots ofall mea-
                          used to examine the flow, salinity, delta        surements made between 1975 and 1989
                          s igma-t, and bottom Do data for long-term       show a distinct seasonal pattern in Pam-
                          trends. The test, which was developed by         lico bottom water oxygen (Figure 5.2a).
                          Hirsch et al. (1982) is a nonparametric          Concentrations <5 mg 1-1 are least common
                          procedure suitable for application to water-     in the winter months (0-15%) and most
                          quality parameters which are often skewed,       common in July (75%). About one-third of
                          serially correlated, and affected by season-     the July measurements are < 1 mg 1-1. This
                          ality. The test compares all possible            pattern is in part a reflection of the effect
                          combinations of pairs of values over time,       that annual water temperature and salinity
                          assigning a plus if an increase occurs from      cycles in the estuary have on oxygen solu-
                          one value to the next, or a minus if a           bility. But other factors must be involved,
                          decrease occurs. If more pluses occur than       since the percent saturation frequency plot
                          minuses, then an increasing trend is indi-       shows the same pattern (Figure 5.2b).
                          cated; conversely, more minuses than
                          pluses indicate a decreasing trend. The             60
                          pairs of values compared are from the                   4-5 mg/1              JANUARY-DECEMBER
                          same "seasonal" period - in this case,              40 3-4mg/1
                          months. In other words, only January                    2-3 mg/1
                          values were compared with other January          130     1-2 mg/1
                          values, only June values were compared               : 1 Mg/1
                          with June values, etc. The data within           20
                          each month were summarized as means,                   A
                                                                           10
                          and the test was run on the monthly means.
                          A significance level (alpha) of 0.10 or less        0
                                                                                           10       8       5      1
                                                                                                 STATION

                                                                              100-
                            100                                              100%              JANUARY-DECEMBER
                                                                >6            80-
                          9L bu -                                          IL         40-60 %
                                                                4-6        2
                                                                           1          20-40 %
                           60.                                2-4        060-   20 %
                          80
                             40                                              40    B

                             20                                              20

                             0                                                20
                                 J F M A M J J A S 0 N D                        10       8
                                                 MONTH                                            STATION

                          Figure 5.5. Frequency of three delta Sigma-t     Figure 5.6. Frequency of five DO concentration
                          ranges (bottom water - surface water) for each   ranges (A) and percent saturation ranges (B)
                          month. Includes all data from our monitoring     for each monitoring station. Includes all data
                                                                              for the period 1975-89

                          stations for t

                                82                                                                                                                                        Chapter 5

                                Instances of strongundersaturation (<40%)                                            hypoxia increases with increasing strength
                                are rare in the, winter but frequent in the                                         ofwater-column stratification, as measured
                                summer months (39-61%).                                                             by delta Sigma-t. On the other hand, the
                                       A plot of all bottom water DO percent                                        scarcity of hypoxia during winter (< 150C)
                                saturations, grouped into six water temper-                                         cannot be due to a lack of water-column
                                ature ranges (Figure 5.3), reveals a sharp                                          stratification because a frequency plot of
                                increase in the probability of moderate                                             delta Sigma-t indicates that stratification
                                hypoxia at temperatures >150C. Below                                                is even more common in the winter than in
                                this temperature, only 4% of the DO mea-                                            the summer (Figure 5.5). Thus, it appears
                                surements, were *less than 40% saturation,                           that the combination of stratification and
                                but above 150C, 38% were< 40% saturation,                                           warm water temperature is most conducive
                                andabove 256C over halfthe measurements                                             to the development ofbottom water hypoxia
                                (52%) were <40% saturation. Severe hy-                                              in the Pamlico.
                                poxia (<20% saturation) is also most preva-                                                Severe hypoxia occurs more frequently
                                lent at the higher water temperatures. In                                           in the upper half of the estuary than near
                                addition, Figure 5.4 shows that for tempera-                                        the mouth (Figures 5.6 and 5.7). When
                                tures above 150C the frequency of severe                                            data for all months are considered, around

                                                                                                                              SW   SE NW W SW            SSWW NESW WSW
                                                                                                                           NW     S   W   NW    W    SE    W   SW    NE    S   SW NW         SW
                                       80
                                                                                     JUNE-SEPTEMBER
                                                                                                                                                           A
                                 70     4-5mg/1                                                              224   . . . . . .
                                                                                                                                                                                4
                                          3-4 mg/1                                                                              FLOW

                                 60 -                                                                             168-                                                                   3
                                               2-3 mg.1
                                       50    1.2 mg/1                                                               112                                                                     2
                                                                                                                       56-
                                       40-
                                                                                                                                                                                              0
                                                                           WIND STRESS (dyne cm)-2                               0
                                       30								WIND
                                               A                                                                           2-                         SURFACE
                                     20                                                                                  4-
                                     10                                                                                  6-

                                                                                                                                         0
                                       0                                                                                   8-
                                                            10                         5             1
                                                                         8                                                                                  . . . . . . . . . . . .
                                                                     STATION                                               10 12i     16        20         24        28         1      1     15
                                                                                                                                          MAY                                       JUNE

                                                                                                                             W    NE   NE NE     NE    N     N   NW SW SW SW NE                  E
                                                                                                                      112                                                                  4
                                                                                     JUNE-SEPTEMBER
                                       100      80-100%                                                                                                     B                                   C
                                                                                                                                           WND
                                                                                                                         84-                                                               -3
                                           EEI 80-W %                                                                             . . .                    . . . . . .

                                       80 60 40 %
                                                                                                                           56-                                                               -2  CD
                                                                                                                                                                                                 W
                                                 20-40 %
                                                                                                                                                                 FLOW
                                     60-                                                                              28-

                                                                                                                           0      . . . . ..                                                 0   z
                                                 B
                                                                                                                           4-

                                       20                                                                                 8                                   SURFACE.
                                                                                                                    16
                                                                                                                        12-
                                       0-
                                                                          a             5                                          BOTTOM
                                                             10
                                                                      STATION
                                                                                                                              2345678910111213
                                                                                                                                                 SEPTEMBER 1989
                                Figure 5.7. Frequency offive DO concentration                                       Figure 5.8. Surface and bottom salinity, Tar
                                ranges (A) and percent saturation ranges (B)                                        River flow, and wind stress and direction for
                                for each monitoring station. Includes only                                          two periods during 1989. Salinity and wind
                                June-September data for the period 1975-89.                                         data are plotted at 3-hr intervals, and flow is
                                                                                                                    the daily mean.

                           StratIfIcation and Bottom Water HypoxIa                                                     83
                           15% of the upper- and mid-estuary mea-           estuary are important factors influencing
                           surements (Stations 10, 8, and 5) give           the timingofthese events. Three sequences,
                           oxygen concentrations <1 mg 1-1, while at        representing a variety of wind and flow
                           Station 1 near the mouth only 2% of the          conditions between May and November,
                           values are below 1 mg 1-1 (Figure 5.6a).         will be summarized.
                           However, there is less spatial variation in          The first time-series covers a period
                           the frequency of oxygen concentrations in        characterized by rapidly decliningTarRiver
                           the 1-5 mg 1-1 range. About 30% of Station       discharge (Figure 5.8a). On May 12 the
                           10 values fall in this range, compared to        discharge at Tarboro was 250 mss-I -
                           25% at stations farther down the estuary.        about three times the long-term average
                           The percent saturations also showa greater       for that time of year. By late May flow had
                           spatial difference in the lowest range than      fallen to more typical rates, around 40 mss-
                           in the higher ranges (Figure 5.6b). From         1, and it changed little from then until the
                           18 to 23% of samples from the upper- and         end of the interval on June 5. Surface
                           mid-estuary stations are less than 20%           salinity responded to the declining fresh-
                           saturated, compared to only 4% at Station        water input by rising from 1 ppt early in
                           1. A similar analysis of data from the           the period to 5 ppt at the end. Despite
                           summer months (June -September) shows            relatively low wind stress (<0.5 dyne cm-2)
                           that even though the frequency of low            early in the period, there was little strati-
                           oxygen increases during warm weather,            fication, as evidenced by the small differ-
                           the spatial pattern does not change; i.e.,       ences between surface and bottom salini-
                           low oxygen is still most common in the           ties. Thus, river flow appeared to be the
                           upper regions of the estuary (Figure 5.7).
                           Concentrations less than 1 mg 1-1 occur in
                           one-third of the samples from the upper
                           estuary, but in only 4% ofthe samples from             S SW SW N NE NE NE NWNE NE SW SW SW NW SE
                                                                                S SW W NW NE NE NE NW NNW NE SW SW SW SE
                           near the mouth. The percent saturation
                                                                                12 .........
                                                                                             is ii -it   i..
                           data show the same pattern. One possible
                                                                            -10-
                           explanation for these spatial patterns is
                                                                                6-
                           that because of its orientation in relation to   A
                                                                                4-
                                                                            0
                           the directions of the prevailing winds, the      0   2-1111
                                                                                                                          E
                           upper estuary is not as well mixed as the            0
                                                                                20-
                                                                                                                       -4
                           lower estuary. Correlation analysis evi-                         PLOW
                                                                                                                       3
                           dence that supports this conclusion will be      Sao-
                                                                                                                       2
                           presented below.
                                                                            LL
                                                                                                            Nb@        1

                                                                                0                                      0  Z
                           Short-Term Variability
                              Unfortunately, the long-term monitor-         -9  4- ;;M-
                                                                       he
                           ing data provide little insight into t
                           short-term dynamics of stratification and
                                                                                           TTO
                           hypoxia in the Pamlico, due to the relatively                              .......
                                                                                16   20   24   28   1    5    9    13
                           long sampling interval (two-three weeks).                  OCTOBER            NOVEMBER
                           But data from the 1989 continuous monitor-       Figure 5.9. Surface and bottom aalinity, Tar
                           ing study show that stratification/hypoxia       River flow, wind stress and direction, and
                           events can develop and break down very           bottom water DO concentration for the period
                           rapidly. These data also stronglysuggest         October 16-November 14,1989. Salinity, wind,
                           that wind and freshwater flow into the           and DO data areplotted at 3-hr interval8; flow
                                                                            is the daily mean.

                          84                                                                                                       Chapter 5

                          dominant control then. But as flow de-                         seiching within the estuary. As the storm
                          creased, wind became more important, as                        approached, wind stress increased and
                          demonstrated by the development of weak                        shifted to the NE. This mixed the water
                          stratification (2 ppt) on 19 May after wind                    column and began to drive saltier water in
                          stress subsided below 1 dyne                CM-2   . This      from the eastern end of the estuary, so that
                          stratification was broken up three days                        by the time the storm had passed on 6
                          later as the winds increased. From then                        September, salinities throughout the water
                          until the end of the period, wind velocities                   column had risen to about 11 ppt. Grad-
                          were variable, with only brief periods of                      ually, over the next 4-5 days, the wind
                          calm. Consequently, there were no sus-                         shifted back to the SW, and surface salinities
                          tained stratification events.                                  decreased slowly to 8-9 ppt. Also, the wind
                               The second sequence (2-13 September)                      velocities declined, allowinga vertical salin-
                          was highlighted by below normal                                ity gradient of about 5 ppt to develop. After
                          freshwater discharge and a strong wind                         9 September both increasi ng bottom sali n-
                          event associated with the passage of a                         ity and decreasing surface salinity con-
                          storm front. The period began with weak                        tributed to the widening vertical salinity
                          westerly winds, high surface salinity (9                       gradient.
                          ppt), and weak stratification (Figure 5.8b).                          No oxygen data are available for these
                          Alens ofsaltier water in the vicinity appears                  first two sequences, but there are Do data
                          to have intruded twice for brief periods on                    for the final sequence, spanning the period
                          2 and 3 September. This movement may                           mid-October to mid-November, 1989 (Fig-
                          havebeen related totidal forcingor internal                    ure 5.9). This sequence is also interesting

                          Table 5.1. Spearman Rank Correlations                          Table 5.2. Spearman Rank Correlations
                          between bottom water DO and selected                           between D Sigma4 and selected variables.
                          variables. F=flow on day ofDO measurement;                     F=flow on day of DO measurement; F-5, F-10,
                          F-5, F-10, and F-15=5, 10, and 15-day lagged                   and F-15=5, 10, and 15-day lagged flows;
                          flows; WS=Wind stress on day of DO                             WS=wind stress on day of DO measurement;
                          measurement; WS-1 and WS-2=1 and 2-day                         WS-1 and WS-2=1 and 2-day lagged wind
                          lagged wind stress; BSAL=bottom water                          stress; BSAL=bottom water salinit . Surface
                                                                                                                                      y
                          salinity; CHLA=chlorophyll a; andDSIGMAT                       samples were analyzed for N and P
                          =deltaSigma-t. Surface samples were analyzed                   concentrations.
                          for N and P concentrations.
                                                                                                                        Station
                                                          Station                        Variable
                          Variable                                                                       10          8           5            1
                                          10           8           5           1
                                                                                         F             -0.210*     -0.081      0.009       0.111
                          F             0.149       -0.030        0.030      -0.167      F-5           -0.204*     -0.085      0.027       0.128
                          F-5           0.139       0.034         0.026      -0.361**    F-10          -0.173      0.110       0.114       0.205
                          F-10          0.112       -0.150        -0.012     -0.201      F-15          -0.199*     .0.030      0.159       0.231*
                          F-15          0.166       -0.087        -0.045     -0.108      WS            -0.184*     -0.257*     -0.197*     -0.221*
                          WS            0.072       0.279**       0.184*     0.062       WS-1          -0.202*     -0.319**    -0.234*     -0.300**
                          WS-1          0.199*      0.293**       0.279**    0.344**     WS-2          -0.108      -0.178      0.028       -0.127
                          WS-2          0.140       0.305***      0.134      0.178       BSAL          0.732***    0.560***    0.452***    0.266*
                          BSAL          -0.477***   -0.446***     -0.400***  _0.145      NO     3-N    -0.262**    0.203*      -0.109      -0.484***
                          NO,-N         0.284**     0.298**       0.146      0.357**     NH     4-N    -0.225*     -0.288**    -0.160      -0.377**
                          NH,-N         0.104       0.241*        0.134      0.366**     P04-P         -0.066      -0.060      -0.160      -0.377**
                          PO'-P         0.113       -0.066        -0.113     -0.067        P<.05
                          CHIA          -0.175      -0.155        0.035 *    -0.023      .-P<01
                          DSIGMAT       -0.665***   -0.674***     -0.742**   -0.432***   ... P<.ooi

                          *P<05
                          **P<01
                          .*.P<.001

                          Stratification and Bottom Water Hypoxia                                                      85
                          because it includes large, short-term fluctu-   ing wind stress combined to turn the water
                          ations in Tar River discharge and wind          column over in a matter of a few hours
                          stress, which interacted to produce four        during the evening.
                          distinct episodes of stratification. The first      Within 48 hours, another stratification
                          was in progress at the beginning of the         event had begun to develop (30 October).
                          sequence on 16 October. Tar River flow          This time, winds switched from the NE to
                          had declined from a previous peak to 20         the NW, and decreased in velocity. This
                          m8s'l, winds were blowing slowly from the       event lasted about 4 days, with a vertical
                          south, and there was a 6 ppt difference         salinity gradient of about 4-6 ppt and bot-
                          between surface and bottom salinities. Also,    tom water DO reduced to around 2 mg 1-1.
                          bottom water DO was extremely low -             It ended late on 2 October following in-
                          well below 1 mg 1-1. The next day, a strong     creased wind stress the previous night.
                          afternoon wind from the south eroded the        The fourth episode began almost
                          salinity gradient, but was not sufficient to    immediately, and for the next three days
                          destroy it. Even stronger winds on the          (4-6 November), there was weak stratifi-
                          19th temporarily broke up the gradient,         cation that was nearly broken on several
                          and finally on the 20th it was destroyed        occasions, but apparently did not com-
                          following a third day of strong afternoon       pletely disappear, since the bottom water
                          wind. At this time, the bottom water DO         DO continued to fall, reaching 1 ing 1-1 on
                          rose dramatically, reaching saturation con-     the 6th. The vertical salinity gradient
                          centration (9 mg 1-1) by 21 October. Subsid-    strengthened on the next day, weakened
                          ing winds on the 22nd and 23rd led to brief     on the 9th following stronger winds, and
                          periods of stratification and lowered DO.       fluctuated between 2 and 6 ppt for the
                          Again, these very sharp fluctuations may        remainder of the sampling period. Bottom
                          have been caused by short-term tidal or         DO also fluctuated, mostly between 2 and
                          seiching effects.                               4 mg 1-1.
                             Meanwhile, in response to widespread             In summary, these time series data
                          precipitation over the Tar basin, a flow        suggest that, at least in the mid-estuary,
                          pulse had been building steadily for about      stratification events and bottom water
                          4 days, reaching a peak of 125 m3s-1 at         oxygen levels are tightly coupled with varia-
                          Tarboro on 22 October. That pulse reached       tions in freshwater discharge and wind
                          the estuary station three days layer, quickly   stress. Stratification can change in a matter
                          reducing the surface salinity to 5 ppt, and     of hours, and episodes lasting from one to
                          setting up the second stratification event,     several days seem to be common.
                          which eventually amounted to a 5 ppt
                          vertical gradient. Bottom water DO fell         Spearman Correlation Results
                          rapidly from 6 ing 1-1 on 27 October to             Results of the Spearman Rank Correla-
                          around 1 mg 1-1 the following day. This         tion analyses tended to corroborate conclu-
                          seems to be a clear example ofstratification    sions drawn from the frequency plots and
                          caused by a moderate pulse of freshwater        the continuous monitoring data. Several
                          spreading out over the estuary surface          variables were tested for correlation with
                          under low wind stress conditions. In addi-      bottom water DO concentration at each of
                          tion, encroachment of saline Sound water,       the four long-term monitoring stations.
                          as evidenced by the slowly increasing bot-      Only data from 1975-89 samplings when
                          tom salinity, strengthened the density gra-     the water temperature was > 150C were
                          dient even more. On the 28th, both the          used (Table 5. 1). Delta Sigma-t (bottom -
                          pass ingof the Tar River pulse and increas-     surface), gave the highest correlation co-

                      86                                                                                  Chapter 5
                      efficient. The oxygen vs. delta Sigma-t            sponse to the strength of the flushing
                      relationship was inverse and was strongest         exerted by freshwater inflow.
                      at the three stations farthest up the estuary.        Wind stress was significantly correlated
                      The only physical variable showinga signifi-       with stratification (Table 5.2) at all stations
                      cant positive correlation to bottom water          when the previous day's wind was
                      Do was wind stress lagged by one day,              considered, but only at one station when a
                      another indication of the rapidity with            2-day lag was used. In addition, the
                      which stratification events are established        strength of these correlations trended
                      and broken up. Tar River discharge, lagged         upward toward the lower end ofthe estuary.
                      5, 10, or 15 days, seemed to be less impor-        This seems logical, since the shape and
                      tant, as the only significant combination          orientation of the Pamlico is such that
                      was the 5 -day lagged flow at Station 1. The       fetch over which the prevailing SW and NE
                      significant positive correlations between          winds blow increases toward the mouth.
                      bottom oxygen and surface N03     -N are inter-
                      preted to result from the presence of larger       Interannual Tr6nds
                      fractions of high No. river water during              Seasonal and interannual variability
                      mixing periods when there is no hypoxia.           of salinity in the Pamlico is determined
                      Note that there was a strong negative              primarily by freshwater runoff. Typically,
                      correlation between DO and bottom salin-           salinity is lowest during the late winter
                      ity. The positive correlation between bot-         and early spring when freshwater inflow is
                      tom oxygen and surface NH      Vandthenega-        highes. The salinity increases to maximum
                      tive correlation between delta Sigma-t and         values in the summer and fall, coincident
                      surface NH, (see Table 5.2) are interesting        with lowest Tar River flow. In some years
                      in that they suggest that stratification in        this seasonal pattern may be upset by
                      the Pamlico may lead to depletion of this          extended periods of precipitation or
                      nutrient in the surface layer.                     drought. For example, 1978, 1979, and
                          Additional Spearman analyses were              1987 were relatively high flow and low
                      made to test for associations between delta        salinity years, while droughts in 1981 and
                      Sigma-t, and two factors that could influ-         1988 resulted in unusually high salinities
                      ence the strength of the stratification -          (see Chapter 4).
                      Tar River flow and wind stress (Table 5.2).           Watercolumn stratification in the estu-
                      Flows were lagged 0, 5, 10, and 15 days,           ary is much more variable than bottom
                      and wind stress was lagged 0, 1 and 2 days.        salinity on a short-term basis. The only
                      The computed correlation coefficients be-          apparent long-term pattern in stratifica-
                      tween flow and delta Sigma-t were signifi-         tion is that its strength and variability are
                      cant (p<.05) for only Station 10 at the            reduced duringyears when bottom salinity
                      upper end of the estuary. As would be              is relatively low, such as 1978-79 and 1987.
                      expected, time lags of 0 and 5 days gave the       This is to be expected, since delta sigma-t
                      strongest correlation for the upper stations,      is influenced primarily by differences
                      whereas 10 and 15-day lags gave the highest        between bottom and surface salinities.
                      coefficients for the outer end of the estuary.         The Seasonal Kendall-Tau test indi-
                      There is a curious trend in the flow vs. delta     cated there were no long-term trends in
                      Sigma-t coefficients, from negative in the         flow, salinity, delta Sigma-t, or DO in the
                      upper estuary to increasingly positive at          Pamlico between 1975 and 1989. For each
                      the lower station. This result could be            of the four stations, none of the test results
                      interpreted to be a result of the salt wedge       were significant at the 90% level (alpha
                      moving up and down the estuary in re-              <0.1).

                         Stratification and Bottom Water Hypoxia                                                        87

                                                                               There is evidence that, at this frequency
                         Event Frequency                                   of reoxygenation, oxygen demand by the
                             Using hourly wind measurements col-           sediments and water column is sufficient
                         lected by Texasgulf duringthe summers of          to lead to hypoxia or anoxia. If the average
                         1980-1985, we calculated the resultant            summer Pamlico benthic oxygen uptake
                         daily vectors ofthe axial (alongthe channel,      rate of 378 PMOI M-2  h-1 measured by Kuen-
                         2950NW or 1150SE) and coaxial (cross-             zler et al. (1984) is applied to the area of
                         channel, 250NE or 2050SW) components of           sediment in the upper and mid sections of
                         the relative wind stress on the Pamlico. At       the estuary where hypoxia is most frequent
                         this level of analysis, the definition of a       (142.4 kM2,   see Nixon 1989, Appendix A),
                         "strong" wind is somewhat arbitrary, but          it appears that the total benthic oxygen
                         the choice of a cross-channel vector equal        uptake might amount to about 41,339 kgd-
                         or greater than 100,000 kM2d-2or an axial         1. If we assume that one-half of the total
                         vector equal or greater than 50,000 kM2       d-  volume of 322.2 x 10'3ins ofwater contained
                         2 (0.24 and 0.12 dyne cm,2)   seemed reason-      in this part of the estuary is below the
                         able based on the frequency with which            pycnocline, then the sediments could lower
                         such winds occur and a consideration that         the oxygen content of the bottom water
                         the generally weaker axial winds may pro-         only by some 0.26 mg 1-1 d-1. At this rate, the
                         duce vertical mixing at lower speeds be-          total oxygen consumed by the sediments
                         cause of their longer fetches. It would be        duringthe longest average interval between
                         useful in subsequent work to consider this        strong wind events (12.4 days in August)
                         problem in more detail.                           would lower the concentration by about 3.2
                             If the preliminary definition is accepted,    mg I`.
                         strong cross -channel and axial wind events           Respiration by plankton and bacteria
                         occurred, on average, with the frequencies        in the water appears to be somewhat
                         given in Table 5.3 during the summers of          greater. Data presented by Davis et al.
                         1980-1985. Thus, there might be, on aver-         (1978, their Figure 4) show concentrations
                         age, a vertical mixingand reoxygenation of        of 2-3 ing 1-1 ofparticulate organic carbon in
                         the bottom water approximately every 8.6          the waters of the Pamlico during summer.
                         days during June, every 11.5 days during          At this concentration, their oxygen uptake
                         July, every 12.4 days during August, and          regressions (see their Figure 52) indicate
                         every 6.5 days during September.                  that 8-14 ing 1-1 of oxygen were consumed
                                                                           during five days in July and 3-5 ing 1-1 were
                                                                           consumed during five days in August.
                         Table 5.3. Frequency of occurrence (number        These rates of water column respiration
                         per month) of strong cross4hannel and axial       are 2.3 to 10.8 times greater that the five-
                         windevents duringthe summers of1980-1985.         day oxygen uptake by the sediments and
                         Assuming that only one day of strong wind is      are sufficiently great that hypoxia and
                         needed to destratify the estuary, we have         anoxia could eas ily result if the water were
                         considered two or more sequential days Of         only mixed every 6.5 to 12.4 days. The sum
                         strong wind as one event. Eventaareaeparated      of these estimated benthic and water col-
                         by two or more days of weaker wind.               umn respiration rates (0.82-2.95 ing I-ld-1)
                         Month      Cross-Channel Axial          Total     compares reasonably well with the ob-
                                                                           served oxygen loss rates during periods of
                         June              1.8          1.7       3.5      stratification in the fall of 1989 (Figure
                         July              2.0          0.7       2.7      5.9). It seems clear that it is the balance
                         August            2.2          0.3       2.5      between oxygen uptake and the frequency
                         September         3.0          1.6       4.6      of strong wind events that largely deter-

                     88                                                                                Chapter 5
                     minesthe spatial extent and duration of          volved in most episodes, and the great
                     the low oxygen problem in the bottom             majority of the kills were reported during
                     waters of the Pamlico.                           the summer. In some cases, dissolved oxy-
                                                                      gen was measured and found to be low in
                     Effects of Hypoxia on Pamlico Blota              the kill vicinity; in other instances low DO
                         Anoxia or hypoxia in estuarine bottom        was inferred from circumstantial evidence
                     waters obviously has the potential to seri-      (e.g., "sulfide-like odors'). Unfortunately,
                     ously impact benthic organisms, either           most of these investigations took place
                     acutely via kills or chronically via physio-     several days after the kills, so that precise
                     logical stress. The short-term effects were      determination of circumstances at the time
                     documented in the Pamlico during the late        of the kill was very difficult. It should also
                     1960s by Tenore (1972), who found that           be noted that hypoxia-related kills of fish,
                     macrobenthos in deeper waters of the estu-       particularly menhaden, occur frequently
                     ary had low species diversity and density        in many other estuaries along the mid-
                     in the summer, and that variations in the        Atlantic and Gulf coasts of the U.S. (e.g.,
                     density were correlated positively with          Turner et al. 1987), under circumstances
                     anoxia/hypoxia. Large kills of the benthos,      similar to those surrounding the Pamlico
                     occurred quickly in the affected areas fol-      episodes.
                     lowing the onset of hypoxia. However,
                     these areas were recolonized by the follow-      Conclusions
                     ing winter. There have been no follow-up             While hypoxia is not the only environ-
                     studies to determine whether the benthos         mental issue of concern in the Pamlico, it is
                     density and distributions have changed in        certainly one of the most important. Be-
                     the Pamlico over the past two decades. It        cause there are documented and potential
                     would be helpful to be able to correlate the     links between low oxygen and kills of fish
                     degree of impact on the benthos with             and commercially valuable shellfish, the
                     changes in the areal extent, frequency,          public has been more attentive to this issue
                     and persistence of hypoxia events. But the       than to most others. As noted above, many
                     data base to allow such an analysis is not       believe that increasing nutrient inputs are
                     available.                                       promoting larger blooms of phytoplankton
                         '71ounder walk" is the local term de-        that eventually lead to more "dead water"
                     scribing movements of large numbers Of           and fish kills than in the past.
                     the fish into shallow waters along the               However, the results of our analysis of
                     Pamlico. The phenomenon typically occurs         the historical data do not support such a
                     in the summer during extended periods of         view. 'Mere has been no trend toward
                     hot weatherandcalm winds, and is usually         lower bottom water DO over the past 15
                     interpreted as evidence ofan hypoxic event       years. In addition, the Spearman Correla-
                     in the estuary. Data obtained from the           tion results detected no cause-and-effect
                     North Carolina Division of Environmental         relationship between nutrients or algal
                     Management show that low DO was                  abundance and bottom water DO. Of
                     suspected to be the cause of most fish kills     course, it could be argued that lag effects
                     investigated in the Pamlico during the           are involved which would not be detected
                     past two decades (NCDNRCD, unpublished           by comparing contemporaneous measure-
                     data). Most of the reported kills were not       ments. However, one of us (Nixon 1989)
                     in the main stem of the estuary, but rather      has searched - without success - for
                     near the heads of relatively small tributary     evidence of a link between either: 1) the
                     creeks. Menhaden were the species in-            size of the winter-spring blooms of phyto-

                        Stratification and Bottom Water Hypoxia                                                  89
                        plankton in the estuary and the frequency      in reducing the rate of increase in nutrient
                        and extent of hypoxic conditions in the        loading may be beneficial in the future.
                        bottom waters of the estuary the following     But reduction in N loading, at least within
                        summer, or 2) the summer bloom and the         any practical constraint, may not result in
                        severity of hypoxia.                           an increase in the oxygen content of the
                            The North Carolina Division ofEnviron-     stratified bottom water of the estuary
                        mental Management has recently desig-          during summer. At that time of year, the
                        nated the Tar-Pamlico as "Nutrient Sens i-     waters of the Pamlico are "wind sensitive,"
                        tive Water,"with the goal ofreducing nitro-    and we will have to accept the intermittent
                        gen loadingto improve water quality in the     hypoxia and anoxia as natural features of
                        estuary. We would not argue that success       the system.

                         CHAPTER6
                         The Pamlico River:
                         Comparisons with Other Estuaries

                         Introduction                                        "One of the things we can do is to look at
                            In the past, relatively few comparative          places like the Chesapeake Bay, the
                         studies of estuarine water quality have             Hudson River and the San Francisco Bay.
                         been made. It has been speculated that the          They were showing the same signs of stress
                         reasons for this include: 1) the widespread         about 10 years ago that the Pamlico is
                         belief among ecologists that estuaries are          showing now. . . the signals are there.
                         so variable that attempts to generalize                                  B.J. Copeland (1987)
                         from one to another are bound to fail; and      information contained in the Nixon report.
                         2) the great difficulty oforganizing, funding,  Anyone interested in comparative estuarine
                         and executing studies of more than one          ecology should consult this source; it is one
                         system (Nixon 1983). During the 1990s,          of the most comprehensive reports on the
                         the U.S. Environmental Protection Agency        subject available at this time.
                         plans to carry out a major, national com-           Another comparative study that pro-
                         parative study of estuaries as part of its      vided useful data was authored by Boynton
                         Environmental Monitoring and Assess-            etal. (1982). Theyrevi       ddataconcerning
                         ment Program (EMAP).                                                   ewe
                            In addition, few comparative analyses        nutrients, phytoplankton production, and
                         ofexistingdata for different estuaries have     chlorophyll a from 63 different estuarine
                         been published. S.W. Nixon, an estuarine        systems. Finally, I have attempted to
                         ecologist experienced in comparative syn-       make some comparisons between the Pam-
                         theses, points out that attempts at such        lico River and the nearby Neuse River
                         reviews are hampered by the relatively          estuary. Unpublished 1985 and 1986 nutri-
                         small number of estuaries that have been        ent and hydrographic data from the Neuse
                         thoroughly studied, by differences in           study were used to illustrate similarities
                         methodology used to produce the data, and       and differences between it and the Pamlico
                         by the problems that arise from spatial and     River.
                         temporal variability within each system         N utrients
                         (Nixon 1983).
                            Nixon (1983) used previously published           Comparing cycles of orthophosphate
                         and unpublished information for his com-        phosphorus in 14 estuaries, Nixon (1983)
                         parative study of fourteen estuaries on the     found that annual mean concentrations
                         Atlantic, Gulf, and Pacific Coasts of the       were less than 1 pM in Chesapeake Bay, in
                         United States. Fortunately, the Pamlico         the mid and lower regions of the Potomac
                         River was one of the estuaries included in      River Estuary, in Apalachicola Bay, Flor-
                         the study. Topics covered include physical      ida, and in Kaneohe Bay, Hawaii. Highest
                         characteristics, nutrients, phytoplankton       mean concentrations were found in the
                         and primary production, zooplankton,            Pamlico River (approximately 4 gM) and in
                         icthyoplankton, benthos, and fish. In this      South San Francisco Bay (about 25 pM).
                         chapter, I have relied heavily on               All the other systems had mean annual

                       92                                                                                 Chapter 6
                       phosphate levels of 1-3 1AM. One feature          effects ofdifferent flushingrates were taken
                       common to most of the estuaries, including        into account (Figure 6.1b). This correction
                       the Pamlico River, is the summer increase         was made by multiplying the annual input
                       in phosphate, particularly at their lower         by the approximate mean annual fresh-
                       reaches. Presumably, the high Pamlico             water replacement time. The estuarine
                       phosphate is due to the large discharge           data appeared to follow the same relation-
                       from the Texasgulf phosphate mine on the          ship found for lakes by Schindler (1978).
                       south shore of the estuary (see Chapter 3).          A comparison of salinity and nutrients
                           The relationship between phosphate            in the Pamlico River and the Neuse River
                       input and concentrations that Nixon devel-        showed that except for orthophosphate
                       oped may provide a clue as to whether or          phosphorus, there was little difference be-
                       not the Pamlico phosphate levels would            tween the two estuaries. Volume-weighted
                       decrease if loadingfrom Texasgulf, orother        monthly medians for the period January
                       sources, were decreased. From a plot of           1985 to December 1986 were calculated
                       phosphate input versus mean annual phos-          and are plotted in Figure 6.2. This method
                       phate concentration for all the estuaries         of presenting the data eliminates bias aris-
                       surveyed (Figure 6.1a), Nixon concluded           ing from different sampling station loca-
                       that indeed there is a correlation between        tions in each estuary relative to the salinity
                       the two. There was considerable scatter in        gradients. The problem is most severe for
                       the data, but this was reduced when the           factors that vary greatly along the salinity
                                                                         gradient. The weighted monthly median
                                                                         salinities ranged from 8 ppt to about 13 ppt
                           2,100                                         in the Neuse and from 8-12 ppt in the
                           :3
                           4.   A                                        Pamlico. Both estuaries had highest
                           0
                           CL  10                                        salinities in the fall and lowest salinities in
                                                                         the late winter. Nitrate nitrogen was
                           z                        MP                   around 1 1LM in both the Neuse and Pamlico
                           z  1           M%
                           <                                             during the summer, and 5-12 tkM in the
                           z
                           <                                             winter (Figure 6.2b). February and March
                           W 0.1
                               1           10          100         1000 median values were higher in the Pamlico,
                                      P04 INPUT (M MOL M  3 Y1           but November and December values were
                                                                         higher in the Neuse. Overall, there seems
                            100                                          to be no significant difference in the nitrate
                                B
                                                                         between the two estuaries. Similarly,
                           0
                           a-  10                                        ammonia nitrogen was higher in the Neuse
                           _j
                                                                         some months and in the Pamlico during
                           z                  0 a USE
                           z  1                                          other months (Figure 6.2c), but there
                           z         E S                                 appears to be no substantial difference
                           W 0.1                                         overall.
                               1                  10                100      Both estuaries, had highest orthophos-
                                       P04 LOADING (M MOL M              phate phosphorus in the summer months
                                                                         (Figure 6.2d), and lowest values in the
                       Figure 6.1. A. Mean annual concentrations of      winter. The winter values were. similar for
                       inorganicphosphorus (ILM) in several estuaries as aboth - around 1 /iM - but the Pamlico
                       function of the estimated annual inputs       of  had higher summer phosphate than the
                       phosphorus. P = Pamlico River estuary. B. Same as
                       above except that inputs have been corrected for  Neuse. The difference was nearly two-fold
                       differences in flushing times (Redrawn fi-om Kgure for most months between June and Decem-
                       14 in Nixon 1983).

                            The Pamlico River: Comparisons with Other Estuaries                                                   93
                            ber. This difference probably reflects the           Bay. The Pamlico average was 18 AM,
                            influence of P loading from the Texasgulf            about the same as the Patuxent River
                            (TG) facility into the Pamlico. The more-or-         Estuary, Chesapeake Bay, Potomac River,
                            less constant TG loading ought to be most            and North San Francisco Bay (Nixon 1983).
                            noticeable in the low-flow periods (i.e.,            Nixon's plots of mean annual DIN concen-
                            summer and fall) when Tar River P loading            tration versus DIN input and loading
                            is reduced.                                          (Figure 6.3), prepared in the same manner
                                Nixon (1983) also compiled data on               as the DIP loading versus concentration
                            annual cycles of inorganic nitrogen (DIN)            plots described above, led him to conclude
                            for a number of estuaries, including the             that there is a linear relationship between
                            Pamlico River. Two of his general conclu-            nitrogen loadingand the average concentra-
                            sions about DIN cycles apply to the Pamlico:         tions observed in the estuaries. But the
                            1) nitrate is often more abundant than               slope of a line drawn through this data
                            ammonia during spring and fall in the                would be less than one, indicating that DIN
                            lower salinity systems, and 2) concentra-            concentrations do not rise or fall in estuaries
                            tions of nitrate appear highest in the upper         in 1:1 proportion to changing loading. It
                            portion of the estuaries. However, the               appears that a doubling in the loading rate
                            range in annual mean concentrations was              ought to produce about a 50% increase in
                            very large; from about 1 AM in Kaneohe               mean concentration.
                            Bay, Hawaii, to over 100 AM in Delaware

                              20-                                                m 14 -
                                                                                 = 12-                                    B
                                                                                 z
                            a.15-          NEUSE             PAMLICO             W10-         NEUSE            PAMLICO
                            IL                                                   0
                                                                                 0  8-
                            M                                                       6-
                                                        X
                                                                                 z
                            -j  5-                                               W  4-
                                                                                    2-
                                                                                 Ir
                                0-                                                  0-
                                  J F M A M J J A S 0 N D                               J F M A M J J A S 0 N D
                                                 MONTH                                                  MONTH

                                                                                 M12-
                            =L                                         C         a                                           D
                            z                                                    a.10-
                            W6-         NEUSE             PAMLICO                W            NEUSE            PAMLICO
                            8                                                    !R 8-
                            04 -                                                    6-

                            z
                            <2-                                                  0  4-
                                                                                    2
                            20-
                                                                                 0
                            0                                                               K
                            2 J     F  M   A M    J   J A    S  0 *'N   D        cr     J  F M A M       J  J  A   S  0   N D
                                                 MONTH                           0                      MONTH

                            Figure6.2. Salinity, nitrogen andphosphorus in the Pamlico River and Neuse River estuaries, 1985-1986.
                            Values are volume-weighted monthly medians. (A) Salinity (ppt), (B) Nitrate nitrogen (AM), (C)Ammonia
                            nitrogen (AM), (D) orthophosphate phosphorus (AM).

                         94                                                                                                                   Chapter 6

                                1000
                                         A                                                          There continues to be much controversy
                                Z                                                                and uncertainty surrounding the issue of
                                    100
                                                                                              nutrient limitation in estuaries. Over the
                                                                                                 past two decades, the general consensus

                                      10
                                                                                                has been that nitrogen is more likely than
                                                                                                phosphorus to limit algal growth. Boynton
                                l
                                       10             100            1000            10000     et al. (1982) compiled data on N:P concen-
                                                   DIN INPUT (M MOL M -3y                        trations and ratios from nearly 30 estuaries,
                                                                                                 including the Pamlico River (Figure 6.4).
                                1000                                                            Here are their conclusions:
                                           B

                                      100                                                             'The data ... support the notion that
                                                                                                      nitrogen is consistently less abundant
                                                                   P
                                      10                                                             than phosphorus during periods of
                                                                                                      peak [algal] productivity in a wide
                                                                                                      variety of estuarine ecosystems. In
                                         0.1          1           10        100         1000          most cases, those those that do not
                                                DIN   LOADING (M MOL       M  .3 Y-1                  follow this patternare heavilyenriched
                                                                                                      by point and diffuse nutrient sources
                             Figure 6.3. A. Mean annual concentrations of                             throughout the year (e.g., HighVenice
                             inorganic nitrogen (IM) in several estuaries as a                       Lagoon, Hudson River). On the right
                             function ofthe estimated annual inputs ofnitrogen.                       side of [Figure 6.4], actual concentra-
                             P = Pamlico River estuary. B. same as above except                       tions of DIN and DIP [orthophosphate
                             that inputs have been corrected for differences in                       phosphorus] at the time of peak produc-
                             flushing times (Redrawn from Figure 17 in Nixon
                             1983).
                                                                                  Nitrogen         Phosphorus Ratios                      ug-at 14
                                         RIVER DOMINATED                      0            10           20           30           40
                                                                                                                                              N P

                                         PAMLICO RIVER, NORTH CAROLINA
                                         NARRAGANSETT BAY, RHODE ISLAND

                                         WESTERN WADDEN SEA, NETHERLANDS                                           1.5     120         3.0/ 2.0
                                         EASTERN WADDEN SEA, NETHERLANDS                                                0.5                  4.0/2.5
                                         KID-PATUXENT RIVER. MARYLAND                                                                     4.2/2.3
                                         LONG ISLAND SOUND. N.Y.
                                         LOWER SAN FRANCISCO BAY, CALIF.
                                                                                                                                            20.6 / 3.8
                                         BARATARIA BAY. LOUISIANA                                                                             4.6/0.8
                                         UPPER SAN FRANCISCO BAY,   CALIF.
                                         VICTORIA HARBOR, BRITISH   COLUMBIA
                                                                                                                                            1.5
                                         MID-CHESAPEAKE BAY,MD.                                                           0.5 20.6.
                                         UPPER PATUXENT RIVER, MARYLAND                                                                     1.12.0
                                         HUDSON RIVER, NEW YORK                                                             60.0 /3.0
                                         APALACHICOLA BAY. FLORIDA                            .............                61              5.0 /0.16
                                         UPPER CHESAPEAKE BAY. NO.                                                                  240     10.0 /0.1
                                                                                                                  52

                             Figure6A. Seasonal mean DIN.DIP ratios from16 river-dominated estuarine ecosystems. Horizontalbar8
                             indicate the annual ranges in DIN.DIP ratios, solid triangles represent ratio at time of maximum
                             productivity. Absolute concentrations (AM) at time ofpeak productivity are on the right. Vertical band
                             represents the typical range of algal composition ratios (part of figure 5 in Boynton et al. 1982).

                          The Pamlico River: Comparisons with Other Estuaries                                            95

                              tion are shown. Clearly, actual concen-       estuary during the late spring, while N
                              trations vary considerably between            limitation is more significant at the mouth
                              various estuaries and it is an open           of the estuary during the summer.
                              question whether these concentrations
                              are limiting. However, nitrogen enrich-
                              ment in estuarine areas often stimu-          Dissolved oxygen
                              lates algal growth, indicating that de-           Chesapeake Bay was one of only two
                              spite relatively high ambient concen-         estuaries found to have serious low Do
                              trations, nitrogen limitation of phyto-       problems in a review of 14 systems by
                              planktonic production can occur               Nixon (1983) (the other was Mobile Bay).
                              (Ryther and Dunstan 1971; Williams            The low oxygen phenomenon has been
                              1972; Goldman et al. 1983; Thayer             experienced for many years in the Chesa-
                              1974)"     (Boynton et al. 1982, page 78).    peake, he noted, and may be, in part at
                                                                            least, a natural feature of the system. The
                              Some ecologists, after making detailed        Bay's deep channel, lying between broad,
                          studies of individual estuaries, have come        shallow, very productive waters, maycollect
                          to the conclusion that phytoplankton              and concentrate much ofthe organic matter
                          growth limitation shifts from N to P at           fixed in the shallows. Nixon speculated
                          different times of the year. There seems to       that this enrichment, combined with a
                          be a seasonal pattern in the shifts. For          well-stratified water column, may cause
                          example, Webb and Eldridge (1988) con-            the anomalous low oxygen feature. In
                          ducted experiments in the lowerYork River         Mobile Bay, the deep channel (Mobile Ship
                          that showed the phytoplankton were P              Channel) is well oxygenated and the low
                          limited in the late fall and winter, and N        oxygen water is spread out over shallows
                          limited in the late spring and summer,            that have been isolated from much of the
                          They speculated that seasonal shifts in p         tidal circulation by shoals and dredge spoil
                          and N inputs to the estuary were the most         (Nixon 1983).
                          likely cause of the shift. In the York River,         I recently attempted an assessment of
                          P shows maximum concentrations in sum-            dissolved oxygen conditions in the twenty-
                          mer and the minimum in winter; the major          three estuaries in North Carolina, South
                          input ofN is nitrate from wintertime runoff.      Carolina, and Georgia for which some data
                          Recall that this is the same as the pattern       were available (Stanley 1985). One con-
                          for the Pamlico River (see Chapter 4).            clusion from this review was that none of
                              These results parallel those from stud-       these estuaries suffer from extended,
                          ies in a low salinity portion of the Chesa-       widely-ranginghypoxia. Rather, the events
                          peake Bay system (D'Elia et al. 1986), and        appear to be of short duration and do not
                          inotherareas ofthebay (Fisheretal. 1988-,         appear to have a serious impact on the
                          Malone 1988; Love et al. 1988). Despite           estuaries, although benthic fauna are
                          extreme nutrient enrichment in the head-          affected temporarily. Lack of long-term
                          waters of the Delaware estuary, phyto-            monitoringdata for all these systems except
                          plankton productivity in the middle and           the Pamlico River makes it impossible to
                          lower estuary alternates between light,           determine exactly how much impact cul-
                          phosphorus and nitrogen limitation over           tural eutrophication has had on the oxygen
                          the seasonal cycle, according to (Pennock         conditions.
                          and Sharp 1988). It is also their view th--'-         Turner et al. (1987) showed that oxygen
                          these factors var*y spatially over the salinity   depletion in the bottom waters of Mobile
                          gradient. In general, Delaware Bay P              Bay is caused by the same factors operating
                          limitation is most prominent in the mid-          in the Pamlico River. They found that

                           96                                                                                                      Chapter 6

                           hypoxia was directly related to the intensity                 their new findings as follows:
                           of water column stratification, which, in
                           turn, was coincidental with low wind                               "Analysis of the complete data base on
                           speeds. More than 80% of the variation in                          measurements of dissolved oxygen in
                           DO content in their samples was explained                          the Chesapeake Bay for the period
                           by variations in the vertical salinity                             1950-1985 results in two conclusions:
                           gradient.                                                          a) there has been no statistically
                                                                                              significant pattern of increase in
                                An analysis showing a trend toward                            summer anoxia of bay waters over the
                           worsening dissolved oxygen conditions in                           past 36 years, and b) annual
                           the bottom waters of Chesapeake Bay has                            stream flow-induced stratification is the
                           been widely publicized (e.g., Officer et al.                       controlling factor in the annual volume
                           1984), but the study conclusions have been                         of summer anoxic waters in the bay, at
                           questioned by other bay-area scientists                            greater than the 99.99% confidence
                           (Seliger and Boggs 1988) who have re-                              level. These conclusions are in sharp
                           examined the data. They summarized                                 contrast with those of an EPA-funded
                                                                                              5-year study of the bay and with those

                                                                                          Chlorophyll a, Mg m-3
                                                                        0              65         10           15            20          2-5
                                                                        1              1           1          1

                           MEYERS CREEK. MEW JERSEY                     SP Su
                           GULF OF ST. LAWRENCE , CANADA                W  Sp
                           FRASER RIVER. BRITISH COLUMBIA               W
    												SU
                           STRAIT OF GEORGIA, BRITISH COLUMBIA          W SU
                           VICTORIA HARBOR, BRITISH COLUMBIA            W- Su
                           HUDSON RIVER, NEW YORK                       W Su
                           ALTAMAHA RIVER MOUTH, GEORGIA                     W
                           MID-ALTAMAHA RIVER, GEORGIA                   W               Su
                           WACCASASSA RIVER. FLORIDA
                           BURRARD INLET, BRITISH COLUMBIA              W,F                            Sp
                           YTHAN ESTUARY, SCOTLAND                           Sp        0       Su
                           APALACHICOLA BAY, FLORIDA                                   F      S P
                           DUWANISH RIVER, WASHINGTON                    W                                   Su
                           LONG ISLAND SOUND, N.Y.                        W              Su
                           NARRAGANSETT BAY. R.I.                       W,   F                          Sp
                           MID-CHESAPEAKE BAY, NO.                       W                                 F
                           COLUMBIA RIVER, WASH.                               W                         Su
                           WESTERN WADDEN SEA. NETHERLANDS                     W                                  W.-Su
                           EASTERN WADOEN SEA, NETHERLANDS
                           BARATARIA BAY. LOUISIANA                                    F            66            W. Sp
                           UPPER CHESAPEAKE BAY. NO.                                                                                      a Suq, F
                          MID-PATUXENT RIVER, NO.                                                                                         38 Su
                           LOWER PAMLICO RIVER. N.C.                                          Su. F                                         W. Sp
                           RARITAN BAY, N.J.                                 W                                                             12& 45 Su
                           UPPER PATUXENT RIVER. NO.                           W                                                 Su

                           Figure 6.5. Summary ofchlorophyll aconcentrations in 25 estuaries. Annual ranges and Seasons in which
                           maximum and minimum concentrations occurred are indicated. Solid triangle indicates chlorophyll a
                           concentration at time of maximum productivity (part of Figure 4 in Boynton et al. 1982).

                          The Pamlico River: Comparisons with Other Estuaries                                                     97

                              of a major review of anoxia published                  any evidence for increased summer
                              in Science [Officer et al. 19841, namely               anoxia since the 1950s, the scientific
                              that anoxia in the bay has increased                   basis of this program should be re-
                              by a factor of 15 since 1950 and that                  evaluated"
                              benthic respiration, rather than strati-                                 (Seliger and Boggs 1988).
                              fication, has been the controlling factor
                              in this 15fold increase in anoxia. This           Chlorophyll a and
                              apparent increase in anoxia has been               Phytoplankton Biomass
                              attributed to increased nutrients and
                              has been assumed to be a major factor                  In his comparative estuarine study,
                              in the decline of fish and shellfish               Nixon (1983) also presented data on the
                              species in the bay. A federal and                  standing crop of phytoplankton, as esti-
                              multi-state program for restoring the              mated by chlorophyll a. The estimated
                              bay biota is based on reversing this 15-            annual mean for the Pamlico River was
                              fold increase in anoxia by reducing                about 16 ug/liter. For all the estuaries, the
                              nutrients in the bay. In the absence of            range was from about 2 jig/liter in Kaneohe

                                                                     Phytoplankton Production, g C m-2 d (net)
                                                                     0        0.5        1.0           1.5        2.0          2.5
                                                                     W SU           I          I            I           I           I
                          ST. LAWRENCE RIVER, CANADA                 W   Su
                          UPPER SAN FRANCISCO BAY, CALIF.            W-. SU
                          FRASER RIVER, BRITISH COLUMBIA               2qo
                          UPPER PATUXENT RIVER, MD.                  w -su
                          STRAIT OF GEORGIA. BRITISH COLUMBIA          W Su
                          WESTERN WADDEN SEA, NETHERLANDS             W             Su
                          SWARTVLEI, SOUTH AFRICA                             Sp
                          WACCASASSA RIVER, FLORIDA                  W       a   SU
                          EASTERN WADDEN SEA, NETHERLANDS           W       0        SU
                          MEYERS CREEK, NEW JERSEY                    SPSu
                          UPPER CHESAPEAKE BAY, NO.             W.   SP6                                 Su
                          HUDSON RIVER, NEW YORK                     W                                                    Su
                          LONG ISLAND SOUND. NY                                 , Su
                          DUMANISH RIVER, WASH.                       W                        Su
                          COCHIN BACKWATER, INDIA                            W       S P
                          BARATARIA BAY, LOUISIANA                   W                                   SU
                          LOWER SAN FRANC1SCO DAY, CALIF.                    W      sis, r
                          mio-PATXUEANT RIVER. MD.                            W                         SU
                          RARITAN BAY, NEW JERSEY                                                        Su
                          NARRAGANSETT DAY. RHODE   ISLAND                   W                                     4                      BURRARD INLET. BR1T1SH COLUMBIA          W                                     Sp
                          APALACHICOLA BAY, FLORIDA                                W-SP
                          MID-CHESAPEAKE BAY. RD.                              W                         F
                          PAMLICO RIVER, NORTH CAROLINA                                 F                                Su
                                                                                      W                                         SU
                          ALTAMAHA RIVER MOUTH, GEORGIA

                          Figure6.6. Summary of average daily phytoplanktonproduction rates (solid dot) in 25 estuarine systems.
                          Horizontal bars indicate annual ranges. Season in which maximum and minimum rates occurred is also
                          indicated W, winter, Sp, spring, Su, summer, F, fall) (part of Figure 3 in Boynton etal. 1982).

                        98                                                                                        Chapter 6

                                                                              Bay, Hawaii, to almost 20 jig/liter for the
                               10
                            _J       A                                        Patuxent River estuary. A winter-spring
                                                      P
                                                                              bloom was found to occur in a number of
                                                                              the estuaries, including the Pamlico, of
                            z   10
                            z                                                 course, but was inconspicuous or absent in
                            z                                                 others. Some estuaries had strong mid-
                                                                              summer blooms.
                                   0.1      1        10       100      1000       Boynton et al. (1982) also presented
                                         DIN LOADING (M MOL M    -3           comparative data on chlorophyll a and
                                                                              average daily primary production rates in
                            <  10                                             thePamlico Riverand in 44 other estuarine
                            _J       B
                                                                              systems (Figures 6.5 and 6.6). The Pamlico
                                                      P
                                                                     %
                                                                              data used in this comparison were from the
                            z   10                                            early-to-mid 1970s. In terms ofboth chloro-
                            z
                            <                                                 phyll a and primary productivity, the
                            z
                                                                              Pamlico ranked as one of the highest of the
                                                                              river-dominated estuaries included in the
                                  0.01     0.1        1        10       100   comparison. However, there is so much
                                         P04 LOADING (M MOL M                 overlap amongthe top third of the systems,
                        Figure 6.7.    Mean annual chlorophyll     a as a     that real differences, if they exist, are
                        function oftheestimatedannual loadingofdissolved      obscured. These plots also cannot take into
                        inorganic nitrogen (top) and dissolved inorganic      account the considerable year-to-year vari-
                        phosphorus (bottom). P = Pamlico River. The           ability in algal biomass and productivity
                        regression line relating mean annual chi a in lakes   within each estuary, so that individual
                        toPloading is from Schindler (1978) (redrawnfi-om
                        Figure 20 in Nixon 1983).                             rankings are impossible. The authors of
                                                                              this paper drew no conclusions regarding
                                                                              the order of the rankings, such as effects of
                                                                              nutrient loading, hydrography, or climate.
                        _40-                                                      One of the most interesting of all the
                        ;:z                                                   comparisons in the Nixon study described
                        ca
                        =   30-      NEUSE              PAMLICO               above was between nutrient loading and
                        to                                                    chlorophyll a (Figure 6.7). The results were
                        _J                                                    described as follows:
                        -J20-

                                                                                         I have made a preliminary
                        010-
                                                  . . . . . . . . . . . .
                                                                                  attempt to relate the annual mean chl
                            0                                                     a averaged over each estuary to the
                                                                                  input of inorganic nitrogen and phos-
                               J F M A M J J A S 0 N D
                                               MONTH                              phorus... The results are not without
                                                                                  scatter, but as abeginningl thinkthey
                                                                                  are impressive enough to merit
                        Figure6.8. Chlorophyll a in the Pamlico River and         attention and further effort.... The
                        Neuse River estuaries, 1986. Values plotted are           response of estuarine phytoplankton
                        volume-weighted monthly medians.                          may not be as dramatic as that of
                                                                                  lakes. While nitrogen and phosphorus
                                                                                  loadings increased 2000 times from
                                                                                  Kaneohe Bay to the most heavily
                                                                                  enriched MERL microcosm, the annual
                                                                                  standing crop of chl a only increased

                           The Pamlico River: Comparisons with Other Estuaries                                                      99

                           Table 6.1. Summary ofphytoplankton data fi-om several east coast estuaries. BAC = Bacillariophyceae
                           (diatoms), CHL Chlorophyceae, CYA = Cyanophyceae, CHR = Chrysophyceae, and DIN = Dinophyceae.
                           S =total number ofspecies found;- D =average cell density (cells 1"), andB =averagebiomass (mgwetmass
                           1-1).

                           South Creek,                     S: 146          47       17        2        7       10       21      0-10
                           This Study                       D: 3.9 x 1(r    14       11        6       61        6        2
                                                            B: 1.60         14       14       <1       16       51        4

                           South Creek,                     D: 52.7 x 106                                                <15
                           Hobbie (1971)                    B: 9.11

                           Pamlico River,                   S: 173          50       18        3        6        8       15      0-20
                           Stanley and Daniel (1985)        D: 4.2 x 106      3      14       <1       59       20        3
                                                            B: 3.37           3       7       <1        8       80        1

                           Gales Creek, NC,                 S: 339          55        7       -         5       22       11
                           Campbell (1973)

                           Cape Fear River, NC              S: 203          66       12        4        1        7       10      11-15
                           Carpenter (1971)

                           Chowan River, NC                 B: 5.61         20       11       22        1       29       17          0
                           Stanley and Hobbie (1981)

                           Neuse River, NC                  S: 297          23       37       14        9        4       13      0-10
                           Stanley (unpublished)            D: 12.5 x 100   12       16       63        3       <1        5
                                                            B: 3.48         15       34        2        6       17       26

                           Currituck Sound, NC,             S: 204
                           Tyndall (1980)                   D: 6.6 x 106
                                                            B: 0.48         13       20       22        5       17       22

                           Chesapeake Bay,                  S: 149          49       13        2        6       17       13      5-20
                           Van Valkenburg et al. (1978)     D: 10 x 106     21       21       10       18       10       20
                                                            B: 3.97         28       <1       <1        6       56        8

                           Chesapeake Bay,                  S: 219          59        1        4        4       19       13        >20
                           Old Plantation Creek,
                           Marshall (1980)

                           James River Estuary,             S: 74           70        9        1        0       11        9       >15
                           Marshall (1967)                  D: 1.3 x 106

                           Narragansett Bay,                S:75            57        2        0        3       19       19     28-30
                           Smayda (1957)                    D: 6.7 x 106    94                                   6

                      100                                                                                Chapter 6

                          about 30-fold. The consequences of            studies were nonquantitative, emphasiz-
                          such an increase may still be pro-            ing systematics, rather than cell counts, or
                          found, of course, and evidence of an          had used preservation techniques (e.g.,
                          apparently linear response to nutrient        formalin solutions) that destroy the micro-
                          input confirms the importance of              flagellates which make up so much of the
                          eutrophication as a concern in estu-
                          arine management. Since maximum               total phytoplankton biomass in estuaries.
                          chl a levels increase with increasing         Hobbie was able to compare his results
                          average values ... it follows that more       with those from a study by Patten et al.
                          intense blooms are part ofthe response        (1963) of the phytoplankton in the York
                          to increased nutrient input. These            River estuary, and he concluded that the
                          blooms, more than the average                 yearly cycles in these two systems were
                          standing crops, may have the greatest         similar. Both rivers had mostly flagellates
                          impact on estuarine water quality"            upriver and more diatoms toward the
                                      (Nixon 1983, page 25-26).         mouth. Also, both had blooms of the
                          Of course, individual estuaries like the      dinoflagellateHeterocapsatriquetra (called
                                                                        Peridinium t7iquetrum inthe Hobbie [19711
                      Pamlico are unlikely to experience changes
                      in nutrient loading as great as the range         report) in late winter and early spring.
                      among these estuaries. Figure 6.7 shows           Although he gave no details, Hobbie com-
                      that the rates of change of chlorophyll a         mented that "the rest of the algae species
                                                                        found in the Pamlico Riverestuaryare also
                      with increasingN and P loadingare actually        found in Chesapeake Bay and farther
                      quite small. This suggests that if N or P         north" (Hobbie 1971, page 30).
                      loading in the Pamlico were to decrease by            By 1985, quantitative phytoplankton
                      50%, the chlorophyll might be expected to         studies had been made for several east
                      decline by only about 10%.                        coast estuaries. Stanley and Daniel (1985b)
                          Chlorophyll a concentrations in the           compiled the results from these for com-
                      Pamlico were similar to those in the Neuse        parison with their more recent Pamlico
                      River estuary in 1985 and 1986, despite           survey (Table 6. 1). They discussed several
                      the higher phosphorus levels in the Pamlico       similarities between the Pamlico phyto-
                      (Figure 6.8). The volume-weighted monthly         plankton pattern and those from the other
                      median chlorophyll a's were highest in            estuaries. First, the Pamlico species com-
                      both estuaries in the summer months and           position, as reflected in the percentages of
                      lowest in the winter months. Fifteen to           species in each algal class, was similar to
                      twenty-five jig/liter values were typical         those for most other estuaries included in
                      during the summer, while the winter con-          the comparison. Generally, diatoms (class
                      centrations were generally 8 4g/liter or          Bacillariophyceae) was the most diverse
                      less. Summer chlorophyll a values seemed          group, followed by the Chlorophyceae
                      to be slightly higher in the Neuse, although      (green algae) and Dinophyceae (dino-
                      the difference is probably not statistically      flagellates). Together, these three groups
                      significant. It should be noted that data         usually comprised 75% or more of the total
                      from the lower Neuse River, where blue-           species.
                      green algal blooms occur, were not used in            Another similarity was that chryso-
                      these comparisons.                                phytes and dinoflagellates appear to be
                          At the time of Hobbie's 1971 Pamlico          predominant in terms of average cell den-
                      study, there had been very few studies            sity and biomass. In addition, the average
                      published of phytoplankton species com-           wet weight biomass and density did not
                      position and biomass along the south-             range widely among those estuaries for
                      eastern U.S. coast. Most of the earlier

                        The Pamlico River: Comparisons with Other Estuaries                                      101

                        which estimates were available. Biomass        most other estuaries. The overall similari-
                        averaged 3.37 mg/liter in the Pamlico, 5.61    ties in patterns of algal abundance in estu-
                        mg/liter in the lower Chowan River, 3.48       aries of this region are striking, given the
                        mg/liter in the lower Neuse River, 3.97 mg/    great seasonal and spatial variability with-
                        liter in Chesapeake Bay, and 0.48 mg/liter     in each of the estuaries. In fact, it appears
                        in Currituck Sound.                            from this comparison that average algal
                           Finally, the microflagellates have been     abundance in the estuaries of this region is
                        found to contribute heavily to the total       much less variable than the seasonal and
                        algal biomass in the Pamlico (Stanley and      spatial variation within any one of the
                        Daniel 1985), in Chesapeake Bay (Van           systems.
                        Valkenburg et al. 1978), and probably in

                          CHAPTER7

                          Trends in the Sounds' Fisheries

                              TheAlbemarle-Pamlico system has sup-              The fish, oyster and game problem of North
                          ported commercial fisheries for over a                Carolina demands serious attention and
                          century, but as the newspaper editorial               vigorous remedies for their restoration.
                          excerpt (at right) suggests, there were               We hang our heads in shame when
                          problems for the industry almost from its             Wilmington restauranteurs advertise
                          beginning. This editorial was prompted by             Norfolk oysters, while the once famous
                          a fisheries convention held at Wilmington,            New River oyster has practically
                          NC in December 1911 "to take some action              disappearedfrom the market Instead of
                          in regard to the great depletion of the               robbing our rivers and bays and sounds of
                          fishingindustries in the State" (Pratt 1912).         their fish and oysters, we should be
                          Politicians, fisheries "experts" and local            conserving theM taking plenty and leaving
                          fishermen participated in the convention.             plenty to increase the supply. But like
                          Many hypotheses were raised to explain                many other matters that have to be solved
                          the demise of the fisheries, and the                  by our law-making bodies, it is hard to get
                          discussion was intense - at times heated;             an application of common sense.
                          but little concrete evidence was available                               Wilmington Star (1911)
                          to substantiate most of the claims and
                          counterclaims. However, the convention            commercial species are reported by county,
                          was followed by some new state regulations        and annual totals are published in the
                          intended to "protect and perpetuate" the          North CarolinaLandings series. Chestnut
                          fishing industry.                                 and Davis (1975) compiled the data from
                              This scenario has, of course, been            the annual reports for the 1880-1973 pe-
                          repeated many times since, as North               riod in their Synopsis of Marine Fisheries
                          Carolina and other coastal states have            in North Carolina. I used the data in that
                          struggled to balance diverse, often               synopsis, along with statistics for more
                          competing, interests in various schemes to        recentyears in theAnnual Summary (1974-
                          manage the commercial and recreational            1979) or monthly reports (1980-1987) of
                          fisheries in our nations estuaries.               North Carolina landings published jointly
                                                                            by the North Carolina Division of Marine
                          Commercial Fisheries                              Fisheries and the U.S. National Marine
                          The Database                                      Fisheries Service (National Marine Fish-
                              The first comprehensive statistical sur-      eries Service 1974-1979; North Carolina
                          vey for North Carolina was made in 1880           Division of Marine Fisheries 1980-1987).
                                                                         '  Only the data from counties in the N.C.
                          and partial or complete surveys have been
                          made at varying intervals since then. Com-        Division of Marine Fisheries Central and
                          plete statistics are available for the years:     Northern Districts were tallied to give the
                          1880, 1887-1890, 1897, 1902, 1908, 1918,          totals reported in this study. These dis-
                          1923, 1927-1932, 1934, 1936-1940, 1945,           tricts include all the coastal counties from
                          and 1950 to date. Monthly landings ofeach         Carteret northward (Chestnut and Davis

                     104                                                                             Chapter 7
                     1975).                                          analysis of the status and trends of the
                         The usual limitations of commercial         Albemarle-Pamlico commercial and recre-
                     landings statistics should be kept in mind.     ational fisheries was made by Hogarth et
                     First, and most important, they measure         al. (1989).
                     the quantity of fish landed, which is not
                     necessarily a good indicator of the abun-       Edible Finfish
                     dance of the species. One reason for this          The development of commercial
                     discrepancy is that fishing"effort" is gener-   fisheries in the Albemarle-Pamlico region,
                     ally not taken into account. Effort fluctu-     especially along the Outer Banks, was
                     ates in response to changes in demand (i.e.,    retarded in the 1800s by the difficulty of
                     price per pound) for the species, fishery       delivering seafoods, while they were fresh,
                     technology, the cost of fishing (e.g., fuel     from these remote areas to the inland
                     prices), weather, and restrictions imposed      consumers. Consequently, the earliest
                     by state and federal agencies. Second, the      fisheries were engaged in catching those
                     fact that fish are landed in a particular       types of fish which could be preserved for
                     county does not necessarily mean that           later sale. Thus, the first commercial
                     they were caught in nearby waters. Even         fisheries up the rivers and sounds
                     worse, no distinction is made in the sum-       concentrated on such species as alewives
                     mary landings reports between fish caught       (herring) and shad, which could be smoked
                     in the sounds and those caught offshore in      orsaltedwithoutlos ing their flavor. These
                     the Atlantic Ocean. Finally, the older data     anadromous species were caught in large
                     are somewhat suspect because there prob-        numbers during their annual spawning
                     ably was underreporting and because dif-        migrations with seines operated from the
                     ferent species in the same group were not       mainland along the shores of Albemarle
                     always tallied separately (Chestnut and         Sound and the Chowan River. These
                     Davis 1975).                                    fisheries, along with whaling, were the
                         A good description ofthe biology ofeach     limit ofcommercial fishingalongthe North
                     of the major commercial species and some        Carolina coast until the mid-1800s (Stick
                     analyses of trends in the North Carolina        1958; Godwin et al. 1971).
                     commercial landings up through the mid-             Commercial fishing really began on a
                     1940s were made by the following con-           large scale in North Carolina following the
                     tributors to the Study of Marine Fisheries      Civil War, as coastal residents came to
                     in North Carolina (Taylor 1951): E.W.           recognize the potential income represented
                     Roelofs (for edible finfishes), A.F. Chestnut   by the seafood in the nearby waters. Seine
                     (oysters), C. Broad (shrimp), J.C. Pearson      fishing spread, and by the 1870s, shad
                     (blue crabs), and WA. Ellison, Jr. (menha-      fisheries were operating around Roanoke
                     den). Later reviews of the catch data can       Island and in Pamlico Sound. An important
                     be found in reports by Godwin et al. (1971)     mullet fishery developed in Core Sound at
                     and the North Carolina Division of Marine       about the same time. The catch was salted
                     Fisheries (1984). David Stick's (1958) book,    and taken to Morehead City where it could
                     entitled The Outer Banks of North Caro-         be shipped out by train (Stick 1958). Pound
                     lina, contains a chapter on the history of      nets were introduced about 1869 and, along
                     fisheries along the North Carolina coast,       with gill nets, proved so efficient that most
                     with interesting details gleaned from a         of the Albemarle haul-seines gradually
                     review of the late nineteenth century           went out of business. During the late
                     printed material and from interviews with       1800s and early 19008, extensive fisheries
                     residents of the area. The most recent          developed for sturgeon near some of the

                             Trends In the Sound's FIsheries                                                                        .105

                             inlets. But this lasted only a few years               Albemarle-Pamlico edible finfish harvest,
                             before sturgeon became scarce (Stick 1958;             but the fishery has been characterized by
                             Godwin et al. 1971).                                   tremendous year-to-year variations. For
                                   Improvements in transportation were              example, the highest landings on record
                             very slow in coming to this area, so that              occurred in 1969, but a sharp drop (about
                             around the turn of the century, when
                             statistics began to be kept on the
                             commercial fisheries, the most important                  25-
                             ones were still alewives and shad, along                        ALEWIFE
                             with the sound and beach mullet fishery.               U) 20 -
                             Between 1887 and 1900, these three                     z  15-
                             accounted for about two-thirds of the total            3
                                                                                    0-
                             edible finfish harvest (Figures 7.1-7.3). It           Z10-
                             was not until after World War II that                  0
                             extensive ocean trawling began for species             -3
                             such as flounder (Godwin et al. 1971).                        0
                                   Up until the early 1970s, alewives, or                  1885 1905 1925 1945 1965 1985
                             "river herring," continued to be the single                                      YEAR
                             most important component of the                           2.5-
                                                                                             CATFISH & BULLHEADS
                                                                                           2-
                                                                                    z
                                   100-
                                       EDIBLE FINFISH
                                   80-                                              z 1-
                             z                                                      0
                             :)    60-                                              -J 0.5
                             0                                                      _j
                             IL
                             Z     41D -                                                   01
                             0                                                             1885 1905 1925 1945 1965 1985
                             -J    20-
                                                                                                              YEAR
                                   0-
                                   1885 1905 1925 1945 1965 1985                       10-
                                                       YEAR                                8-                   AMERICAN SHAD
                                   50                                               z
                                                                                    D      6-
                                     SHELLFISH                                      0
                             840.                                                   CL
                             z                                                      Z      4
                             030-                                                   0
                             fl@                                                    -J     2-
                             Z20-
                             0                                                             0
                             _j
                             _J10-                                                         1885 1905 1925 1945 1965 1985
                                                                                                              YEAR
                                   0
                                   1885 1905 1925 1945 1965 1985
                                                      YEAR                          Figure 7.2. Trends in anadromous species
                                                                                    landings in the Albemarle-Pamlico Sound
                             Figure 7.1. Trends in total edible finfish and         system. "Alewife" includes alewives (Alo8a
                                                                                    pseudoharengus) and blueback herring (Aloaa
                             shellfish commercial landings in the                   aeetivalis). Another common name for the
                             Albemarle-Pamlico Sound system. Data                   group is "river herring." Data are from sources
                             sources are given in text.                             given in text.

                         106                                                                                         Chapter 7

                        20                                                  _20

                               GREY SEATROUT                                           FLOUNDER

                         15                                                  15

                         l0                                                  10

                          5                                                       5

                         0
                                                                              0
                           1885      1910      1935       1960      1985          1885     1910      1935       1960      1985
                                               YEAR                                                    YEAR

                         25                                                  7
                              CROAKER
                         20                                                  6   BLUEFISH
                                                                             5

                         15                                               4
                                                                              3
                         10                                                   2
                         5-
                                                                              1
                         0                                                     0

                           1885      1910      1935      1960       1985         1885       1910      1935       1960       1985
                                               YEAR                                                    YEAR
                         10   SPOT                                             4  MULLET
                          8                                                 3

                           6-
                                                                               2
                           4
                                                                               1
                         2
                                                                             0
                                 0
                        1885     1910      1935      1960      1985          1885       1910      1935       1960       1985
                                               YEAR                                                    YEAR

                         Figure 7.3. Trends in annual landings of the major types of edible finishes in the Albemarle-
                         Pamlico Sound system. Data are from sources given in text.

                         50%) occurred the following year (Figure              catch (Godwin et al. 1971). However, the
                         7.2). The fishery declined to around 7                report went on to say that "the failure of
                         million pounds per year in the mid-1970s              the fisheryto recoversince thereduction of
                         and has fluctuated around that level since,           foreign fishing is probably related to poor
                         although an all-time low was reached in               water quality in the Chowan River and
                         1987. ADivision ofMarine Fisheries report             Albemarle Sound." No specific hypotheses
                         in 1984 attributed at least the initial decline       linking water quality to the fishery were
                         to increases in offshore landings by foreign          mentioned.
                         vessels, which apparently led to later                     Around 1900, six-to-eight million
                         agreements with the foreign governments               pounds of shad (primarily American shad)
                         involved to reduce their offshore herring             were caught in the Albemarle region each

                           Trends in the Sound's Fisheries                                                              107

                           year, but during the first half of this cen-          Besides the increased fishing pressure,
                           tury, the fishery declined precipitously in       there may be other factors involved in the
                           North Carolina, and in other states along         striped bass decline. ManoochandRulifson
                           the Atlantic seaboard. Since that time, the       (1989) used results from long-term studies
                           fishery has not recovered, and during the         ofstriped bass reproduction in the Roanoke
                           last decade has lingered around 0.2 to 0.5        River to develop a hypothesis linking river
                           million pounds per year (Figure 7.2). Due         flow and the survival ofyoungstriped bass.
                           to the drastic decline of this species, it was    Theiranalyses are based primarily on data
                           studied extensively in the 1950s and 1960s.       collected each year since 1956 by a North
                           Walburgand Nichols (1967) cited the three         Carolina State University researcher, W.W.
                           factors which are so frequently mentioned         Hassler. The followingdescription oftrends
                           in discussions of fishery declines: 1) habi-      in those data is excerpted from the Manooch
                           tat destruction, 2) pollution, and 3) over-       and Rulifson report:
                           fishing. Dams on some of the rivers have
                           prevented the shad from reaching their                "Although no apparent trends were
                           natural spawning grounds and eliminated               detected in the total striped bass egg
                           many miles of nursery areas. Pollution,               production in the river, the viability
                           particularly that which lowers dissolved              rate of those eggs declined drastically
                           oxygen levels in the water, are thought to            beginning in the mid-1970s. Egg
                                                                                 viability ranged from 80% to 96% from
                           be harmful, particularly forjuvenile shad.            1960 through 1974, but declined to
                           Paper mills located on the lower reaches of           56% in 1975 and ranged from 23% to
                           the Chowan, Roanoke and Neuse rivers in               74% in the succeeding years through
                           North Carolina produce high oxygen-de-                1987 (Figure 7.5). In the past, the
                           manding organic wastes (i.e., BOD) which              Roanoke/Albemarle striped bass popu-
                           may have contributed significantly to this            lation has been supported by dominant
                           problem, particularly in the past when                yearclasses produced at approximately
                           there was little treatment to remove the              5-year intervals. A dominant year
                           BOD. Finally, Walburgand Nichols (1967)               class, indicated by a juvenile
                           concluded that fishing pressure has been              abundance index of at least 10 young-
                                                                                 of-year fish per trawl tow, has notbeen
                           an important factor in shad abundance,                produced since 1976 (Figure 7.5). The
                           but up until at least 1971, there were no             estimated number of striped bass in
                           laws or regulations in North Carolina which           the spawning migration remained
                           specifically applied to the management of             within historical levels through the
                           the shad fishery (Godwin et al. 1971).                mid-1970s, but in 1980, that number
                              After an apparent decline in the early             also declined. Since 1981, the
                           1900S catches ofstriped bass rose gradually           estimated spawning population has
                           between 1920 and the mid 1960s (Figure                remained below 100 thousand fish."
                           7.4). Then, beginningin 1967, striped bass            The authors of this report go on to
                           were caught by ocean trawlers fishing off         discuss several aspects of the life cycle of
                           the northern Outer Banks. The landings            striped bass which are affected by river
                           quadrupled, from one-half million pounds          flow. They conclude that the construction
                           to 2 million pounds, and remained high for        ofsix upstream dams on the Roanoke River
                           several years. Then, after a record catch of      in the 1950s and 1960s, and the resulting
                           2.3 million pounds in 1970, the landings          water flow regulation, has had a negative
                           began a decline that was not halted until         impact on the striped bass. Finally, the
                           the early 1980s, but by then the catches          report makes recommendations to the U.S.
                           were at historic lows of 100-200 thousand         Army Corps of Engineers and the electric
                           pounds.

                       108                                                                                             Chapter 7

                         2.5-                                                      6-
                       -          LANDINGS                                            EGGSSPAWNED
                       V)                                                          5-
                       z     2-
                       0                                                           4-
                         1.5-
                                                                                Z3-
                                                                                0
                                                                                -J2-
                       z 0.5
                       n
                       0 0                                                         01
                       CL    1885    1910       1935      1960      1985           1956     1964       1972       1980      1988
                                                YEAR                                                    YEAR

                         80-                                                       100-
                               RECREAT10NAL CATCH
                                                                                    80-
                         60-
                       U_
                       0                                                            60-
                       U)40-                                                    z
                                                                                W
                                                                                0   40-
                       z                                                        cc
                       @20-                                                     Uj
                                                                                    20- EGG VIABILITY
                       0
                             0.                                                       0-
                             1956   1964        1972     1980       1988             1956      1964      1972      1980      1988
                                                YEAR                                                     YEAR

                         0.6-                                                      30-
                         0.5-   SPAWNERS                                                    JUVENILE ABUNDANCE INDEX

                         0.4 -                                                     20-
                       U_
                       00.3-
                       CO
                       z 0.2-
                       0
                       :3
                         0.1 -
                             01
                             1956    1964       1972     1980       1988            1956      1964       1972      1980       1988
                                                YEAR                                                     YEAR

                       Figure 7.4. Trends in Albemarle-Pamlico                  Figure 7.5. Trends in eggs spawned, egg
                       region commercial catch of striped bass, and             viability, andjuvenile abundance indexfor the
                       Roanoke River recreationalcatch, andnumbers              Roanoke River striped bass population. Data
                       of spawning striped bass. Commercial catch               are from Mannoch and Rulifson (1989).
                       data arefrom sourcesgiven in text. Recreational
                       catch and spawningpopulation data are from
                       Mannoch and Rulifson (1989).

                          Trends in the Sound's Fisheries                                                              109

                          power company, who operate the dams. In
                          order to increase striped bass reproductive           "Blue crabs are very abundant on this
                          success, discharges from the reservoirs               coast, but they are not much in demand
                          should be regulated during the spawning               as food. Above Morehead City and
                          period so that flow in the lower Roanoke is           Beaufort, the fishermen take them in
                                                                                immense numbers in their drag-nets
                          kept as close as possible to the average              while fishing for sea-trout, mullet and
                          rate, for that time of year, that existed             other fish, and consider them a great
                          before the dams were built (Manooch and               annoyance, as it is difficult to remove
                          Rulifson 1989).                                       them from the nets. They kill nearly
                              The declines in anadromous species                all that are captured in this way by a
                          landings have been more than offset since             blow from a stick carried along for the
                          1960 by dramatic increases in catches of              purpose, and then throw them away,
                          five edible marine finfishes: grey seatrout,          or use them as manure. A few are kept
                          flounder, croaker, bluefish and spot. Trends          for food, but none are sold, beyond an
                          in landings of these five have been very              occasional barrel-full, mostly soft-
                          similar. They all increased rapidly in the            shelled, which are sent to some of the
                          1970s, peaked around 1980, and have fallen            larger inland towns."
                          back somewhat since then (Figure 7.3).                In the 1930s, the crab industry began
                              The North Carolina Division of Marine         to grow, partly because of new crabbing
                          Fisheries has monitoredjuvenile fish abun-        methods, but mainly because of an
                          dance within the Albemarle-Pamlico sys-           increasing demand for imported crabmeat
                          tem since 1979. The data are used to              in northern markets. Pearson (1951)
                          generate year-class strengths for four fin-       described the close inverse relationship
                          fish species: Atlantic croaker, spot, south-      that existed in the 1930s and 1940s between
                          ern flounder, and weakfish (grey sea trout).      crab harvests in North Carolina and the
                          No significant trends for any of these speies     Chesapeake Bay. In years when the abun-
                          are indicated between 1979 and 1988.              dance of crabs in Chesapeake Bay was
                          Years of relatively high abundance were           insufficient to satisfy the markets, more
                          1982 and 1986 for southern flounder, 1981         North Carolina crabs were harvested and
                          and 1986 for weakf ish, and 1983 for Atlan-       exported to markets in the Chesapeake
                          tic croaker. The absence of downward              region. This led to the beliefby some North
                          trends indicates that any stress on these         Carolina fishermen that a high natural
                          species (such as overfishing) is not great        abundance of crabs in one region was
                          enough to cause a decline in relative juve-       accompanied by a low abundance in the
                          nile production. Fluctuations are most            other and vice versa.
                          likely due to yearly variations in environ-           The rapid increase in North Carolina
                          mental parameters, such as temperature,           crab landings after 1950 (Figure 7.6) was
                          salinity, weather patterns, and/or currents-      undoubtedly due in part to decreased
                          These factors all affect larval transport         dependence on the Chesapeake markets.
                          and survival (Hogarth, et al. 1989).              At the same time, more and more processing
                          Blue Crabs                                        factories were beingbuilt in North Carolina.
                                                                            Prior to 1930, there were no more than half
                              There was a minor blue crab fishery in        a dozen crab-picking plants in the state.
                          North Carolina as early as the 1880s and          Although a crab meat canning industry
                          1890s, but the demand was apparently              had been established in Beaufort in 1943,
                          much smaller than the catch, as indicated         by 1946, there were still only 16 crab
                          in this 1887 report by Rathbun:                   houses in the state, compared to over 100

                    110                                                                            Chapter 7
                    on Chesapeake Bay (Pearson 195 1). How-         who fished for spot, croaker and butterfish
                    ever, in the late 1960s, several factories,     in Pamlico Sound (Earll 1887). But later
                    each employing hundreds ofworkers, were         the demand began to increase gradually.
                    built along the western shores of Pamlico       Between 1912 and 1915, Federal Bureau
                    Sound (Godwin et al. 1971), and by 1984,        of Fisheries personnel at Beaufort used an
                    there were more than 25 processing plants       otter trawl to collect specimens for their
                    in the area (North Carolina Division of         research. North Carolina fishermen
                    Marine Fisheries 1984).                         adapted and modified this gear and the
                       After reaching historic highs of around      shrimp fishery began to grow rapidly
                    20 million pounds in 1964 the landings          (Figure 7.6). The landings increased to an
                    declined nearly 50% by 1968, presumably         all-time peak of 13 million pounds in 1953
                    due to mass mortalities of blue crabs that      (Godwin et al. 1971).
                    occurred from North Carolina to Florida.           'Destruction of the estuarine habitat of
                    An emergency investigation was authorized       young shrimp" was mentioned by Godwin
                    to find the cause, but by the time the study    et al. (1971) as the probable cause of the
                    finally began, the mortalities were over        decline in shrimp harvests after 1953, but
                    and landings had returned to their former       no details were given. There has been no
                    levels. The study showed the presence of        obvious trend in the shrimp landings since
                    several pesticides and disease organisms        1960, but often they have fluctuated widely
                    in blue crabs, but failed to make any           from one year to the next (Figure 7.6).
                    conclusions concerning possible causes for      Such variations are to be expected in a
                    the mortalities (Godwin et al. 1971).           fishery based on an annual crop which is
                       After 1969, the crab harvest again           greatly dependent on environmental
                    declined for several years, to a low of 11      conditions duringthe critical growth period
                    million pounds in 1975. Briefnotes included     (North Carolina Division of Marine
                    in the Annual Summaries of landings             Fisheries 1984). Salinity and temperature
                    during that period included suggestions         are two variables widely thought to have
                    that since demand was good and prices           great influence on the annual harvests.
                    were high, "only a general scarcity of crabs    Although no statistical analysis appears to
                    could account for the decline in landings"      have been made between these factors and
                    (National Marine Fisheries Service 1974).       the shrimp landings, they are frequently
                    But in a few years, the annual catches          mentioned in discussions of fluctuations in
                    began a steep rise again, so that by 1980,      the annual catches. For example, the low
                    they were higher than ever - nearly 35          catches in 1978, 1981 and 1984 were
                    million pounds. Landings for all years in       attributed to unusually cold winters and
                    this decade except one have been above 25       heavy springrains (North Carolina Division
                    million pounds (Figure 7.6), making crabs       of Marine Fisheries 1984; National Marine
                    the single most important component of          Fisheries Service 1978, 1981).
                    the North Carolina commercial fishery, in
                    terms of pounds harvested.                      Oysters
                                                                       Before the Civil War, shellfish such as
                    Shrimp                                          the oyster were more important as an
                        Shrimp, like blue crabs, have shown a       industry in the northeastern states than in
                    remarkable growth in popularity as a choice     the southern states primarily because of
                    seafood since the early part of this century.   better railroad systems, but in the late
                    In the 1880s, shrimp were also regarded as      1800s, it became an even bigger industry
                    "trash," and thrown away by haul-seiners        in the north due to a new steam canning

                                     Trends In the Sound's Fisheries

                                         40                                                                       14-
                                         35-    BLUE CRABS                                                               SHRIMP
                                                                                                              212-
                                     Z 30-                                                                    z
                                     025-                                                                     :110-
                                     (L                                                                       0
                                     LL 20-                                                                   CL    8-
                                     0                                                                        LL
                                         15.                                                                  0     6-
                                     U)                                                                       (0
                                     z 10-                                                                    Z     4-
                                     0                                                                        0
                                                                                                                    2-
                                          0
                                          1885         1910          1935         1960         1985           2     0-
                                                                     YEAR                                           1885        1910          1935         1960           1985
                                                                                                                                              YEAR

                                         1.2                                                                      8-
                                     Cn         HARD CLAMS (MEAT)                                             U)
                                     0 1-                                                                     07-                              OYSTERS (MEAT)
                                     z                                                                        z
                                                                                                              :)6-
                                         0.8-                                                                 0
                                     0                                                                        IL5-
                                     IL
                                     U. 0.6 -                                                                 U.4-
                                     0                                                                        0
                                     rn 0.4 -                                                                 co3-
                                     z                                                                        z
                                                                                                              02-
                                     C) 0.2 -                                                                 :1
                                          0                                                                   20-                                                             _J
                                          1885         1910          1935         1960         1985               1885         1910          1935          1960          1985
                                                                     YEAR                                                                    YEAR
                                         2-                                                                       3.5-
                                             BAY SCALLOPS (MEAT)                                                         OTHER SHELLFISH
                                     z                                                                              3-
                                     n                                                                        z
                                     0                                                                        :) 2.5-
                                                                                                              0
                                                                                                              CL 2-
                                     U.1 -                                                                    U_
                                     0                                                                        01.5-
                                     co
                                     z                                                                        U)
                                     0                                                                        z
                                     .J                                                                       0
                                     _J
                                     2 0                                                                          0.
                                         1885        1910          1935          1960         1985                  1885         1910         1935         1960          1985
                                                                   YEAR                                                                       YEAR
                                     Figure 7.6. Trends in annual landings of the major types ofshellfish in the Albemarle-Pamlico
                                     Sound region (N.C. Dividion of Marine Fisheries "Central and Northern Districts"). Shrimp
                                     landing pounds are "heads on. " Data sources are given in text.

                                     process for oysters, the expanded railroad                               were located in New Bern, Beaufort,
                                     systems to carry them to markets, and a                                  Washington, and other small cities in the
                                     booming postwar economy which allowed                                    region. The most important beds were in
                                     more people to buy products like oysters. It                             the vicinity of Ocracoke Inlet (Winslow
                                     was not long before the supply was                                       1889). The late 18808 scarcity of oysters in
                                     exhausted in estuaries such as the                                       the Chesapeake Bay region had an
                                     Chesapeake Bay, and new sources ofoysters                                important impact on oyster production in
                                     were needed.                                                             North Carolina; experienced Chesapeake
                                          Before about 1890, Oysters were                                     oystermen and their dredging fleet moved
                                     harvested in North Carolina only to supply                               into North Carolina waters. The influx of
                                     local markets. In the 18808, these markets                               these oystermen, with their more efficient

                      112                                                                                    Chapter 7

                      dredging and tonging methods used in                cluded that the reason for the decline was
                      Maryland and Virginia, led to sudden                "close and indiscriminate dredging in the
                      increased production for North Carolina,            past two seasons."
                      coinciding with the decline in Maryland                 In the 1880s, conservation groups,
                      (Chestnut 1951). North Carolina                     scientists and concerned citizens were
                      oystermen complained bitterly:                      becoming aware that certain fisheries were
                                                                          declining. The American Fisheries Society,
                         "The people here are poor and depend             founded in 1870, was one of the first groups
                         entirely upon the waters for support.            to call for government action, and in 1872,
                         But the Virginia men are down here               the federal government created the United
                         and have taken entire possession ofall           States Fish Commission to investigate
                         the oyster grounds; their boats are              fishery problems. North Carolina, like
                         much largerthan those here, and when
                         these are at work the Virginians will            other states, was prompted to follow the
                         run down upon them and tear them                 federal government's example, and in 1887,
                         up; and when they try to retaliate it is         formed its first shell-fish commission to
                         useless, for they are armed to the teeth         examine local fishery problems much of
                         with Winchester rifles and some have             the early efforts of the commission were
                         36 lb. guns. Unless something is done            directed at oysters.
                         to stop their dredging, these people                 Through a series of laws and regulations
                         will be in a starving condition in twelve        enacted particularly in the period from
                         months" (Whitehurst 1891).                       1891 to 1925, the Fisheries Commission
                         The exploitation of Pamlico Sound by             attempted to control the growth and
                      the northern fleet was brief, for laws were         development of the shellfish industry in
                      immediately passed shortening the season            North Carolina. But the agency had only
                      and prohibiting non-residents from dredg-           marginal success early on, for at least
                      ing in the State (Thorson 1982). Mean-              three reasons, accordingto Thorson (1982):
                      while, the local residents adopted the dredg-       1) commercial fisheries are difficult to
                      ing methods that had been introduced, so            manage because they are affected by so
                      that when the season was lengthened in              many variables; 2) there was little known
                      1897, production of oysters greatly in-             about the ecology of the fishes and
                      creased. The followingyear new and exten-           shellfishes, and the Fisheries Commission
                      sive beds were discovered two miles or              carried out very little scientific research of
                      more offshore in Pamlico Sound. More                its own; and 3) the agency was
                      oysters were harvested that year (1898)             underfunded and understaffed.
                      than ever before or since in the history of             Oyster landings in the Albemarle-
                      the industry. The supply seemed inex-               Pamlico system have trended downward
                      haustible, and increased preparations were          almost continuously since the late 1890s
                      made for the next year. But when the                (Figure 7.6), a pattern similar to that for
                      season opened in 1899, oysters were scarce.         most other oyster producing areas. With
                      What followed was typical of the debates,           one exception, annual catches since 1953
                      and uncertainties, that have persisted ever         have all been less than 1 million pounds,
                      since about the reasons for fluctuations in         generally fluctuating between 200
                      annual harvests of oysters and other com-           thousand and 500 thousand pounds. The
                      mercial fish and shellfish. Some attrib-            catch in 1987 was 1.2 million pounds, the
                      uted the scarcity to overfishing, others to         highest in 34 years.
                      severe storms that had occurred in August               Trends in the North Carolina oyster
                      and October of 1899. Grave (1904) con-              harvests up until 1945 were discussed by

                          Trends in the Sound's Fisheries                                                             113
                          Chestnut (1951), who attributed the ups          and threatened the economy of shellf"ish
                          and downs to a variety of causes. These          producingstates. Consequently, the indus-
                          included varying intensity of harvesting         try, along with various state and federal
                          effort, changes in laws and regulations,         health agencies, began to formulate a plan
                          planting of oysters and shells, the Great        for sanitary control oftheshellfish industry
                          Depression, and fears about disease              (N.C. State Board of Health 1956). One of
                          outbreaks in other parts of the country          the responsibilities of the Shellfish
                          which presumably were caused by eating           Sanitation Program in each state is to
                          oysters.                                         monitor shellfish growing areas for the
                              Chestnut's discussion is most notable        purpose of determining which areas shall
                          for the one variable not mentioned as a          be open to shellfish harvesting. In North
                          factor in the NC oyster harvest: water           Carolina, the first survey was made
                          quality. Ina companion paper summarizing         sometime between 1925 and 1930, and
                          the hydrography of the sounds, by Nelson         additional surveys have been made
                          Marshal, it was surmised that at the time        periodically since then. In recent years,
                          (the late 1940s) "pollution of North             the most thorough surveys ofall the State's
                          Carolina's marine waters is restricted to a      shellfishing grounds are made about every
                          few local situations mostly in the vicinity of   three years - Data collected during these
                          towns and cities where toilet sewage, and,       surveys provides some information about
                          in a few instances, industrial sewage, is        trends in sewage pollution in various
                          either untreated or inadequately handled"        regions. Today, waters are closed to
                          (Marshall 195 1, p 58). He cited as evidence     oystermen when tests show there are more
                          for this conclusion the State Board ofHealth     than 14 fecal coliform organisms per 100
                          statistics on areas closed to the harvesting     ml of water, a standard established by the
                          of oysters. As of April, 1949, about 27,000      U.S. Food and Drug Administration and
                          acres were closed. In fact, this is one ofonly   the Public Health Service. The original
                          two references to pollution in the volume        measures set up in the 1920s were 70 fecal
                          containing this paper. The other concerns        coliform bacteria per 100 ml ofwater (Peters
                          the effect of poor water quality on the shad     1989).
                          fishery farther inland in some ofthe coastal        North Carolina has about 2 million
                          rivers. This lack of emphasis on water           acres of coastal waters, but portions of
                          qualityas an issue affectingthe NC fisheries     these waters are low-salinity and freshwa-
                          in the 1940s is significant, in light of the     ter areas that do not support shellfish.
                          fact that this was probably the most             Waters suitable for shellfish comprise 1.42
                          thorough synthesis ofavailable knowledge         million acres ofthis total, accordingto N.C.
                          of the estuaries of North Carolina up until      Shellfish Sanitation Program estimates.
                          that time.                                       In 1988, 51.7 thousand acres (3.6%) of
                             Shellfish Sanitation Programs designed        these waters were closed to shellfishing
                          to monitor and regulate oyster and clam          (North Carolina Division of Health Ser-
                          harvesting in North Carolina and other           vices 1988). Only about 30% (15 thousand
                          producer states have been in existence for       acres) of the total closed area was in the
                          about 65 years. During 1924 and 1925,            Pamlico-Albemarle region north of Core
                          outbreaks of typhoid fever in Chicago, New       Sound. Most of the prohibited areas were
                          York, Washington and several other cities        south of Pamlico Sound, in the Morehead
                          were determined to have been caused by           City/Beaufort area and in Brunswick
                          sewage-polluted oysters. The resulting           County south of Wilmington.
                          publicity paralyzed the oyster industry             The data collected since 1971 indicate

                     114                                                                            Chapter 7
                     that in the Albemarle-Pamlico region           industry in North Carolina is heavily
                     closures in some areas are increasing much     influenced by economic factors, some
                     more rapidly than in others. Figure 7.7        originating outside the state. Forexample,
                     shows that, since 197 1, the total amount of   clams are normally more important in the
                     prohibited area in the Pamlico-Albemarle       Albemarle-Pamlico region than oysters,
                     area has not changed a great deal.             but fluctuations in clam prices can have an
                     However, the lack of a trend is somewhat       effect on the oyster harvest. Most North
                     misleading, as was pointed out in a recent     Carolinaclams areexportedto the northern
                     Shellfish Sanitation Program report.           states. But in years when the supply there
                     Improvements in some areas have been           is plentiful, clam prices may decline so
                     offset by increases in closures in a few       much that N.C. fishermen go after the
                     areas with the most rapid population           oysters with more effort than. at other
                     growth, such as Dare County, where the         times when clam prices are higher.
                     permanent population increased 40%                 Early attempts at oyster rehabilitation
                     between 1980 and 1986. Dare County             by the state began in the 1920s and 1930s,
                     increased 65% in prohibited shellfishing       but were later judged to have been
                     acreage during the same period. In Hyde        unsuccessful due to a lack of knowledge of
                     County, the population growth was              oyster biology and selection of unsuitable
                     negligible, but there were agricultural        planting areas. In 1947, the state enacted
                     activities that led to an increase of 818      legislation to begin a new program of
                     acres closed since 1980 (North Carolina        planting seed oysters and shells by the
                     Division of Health Services 1988).             Division of Commercial Fisheries, which
                     Naturally, state officials are worried that    was augmented by University of North
                     such rapid growth in some of these coastal     Carolina Institute of Fisheries Research
                     areas could greatly increase the shellfish     studies. An analysis of the oyster program
                     closures in the future.                        in 1970 showed that despite the efforts to
                        In addition to sewage pollution, other      improve the fishery, the landings had
                     factors such as weather, diseases,             continued to decline. In 1970, the return of
                     economics, and management activities play      commercial production to the fishery was
                     important roles in setting the annual
                     harvest of oysters and clams in the
                     Albemarle-Pamlico region. In some years,          20-
                     the conditionally-approved areas may be                                ACRES CLOSED
                     closed for several days or weeks following        15-
                     heavy rains, which lead to temporary           co
                     increases in the fecal coliform counts. Also,  z
                                                                    610-
                     parasitic organisms that kill oysters are a    n
                     serious threat to the fishery. "Dermo" (the    ox 5 -
                     infectious protozoan Dermocystidium
                     marinum = Perkinsus marinus) is the most           01
                     prevalent disease, but.another, named             1970      1975     1980     1985      1990
                     MSX, showed up in 1988 in some beds                                 YEAR
                     (Davis 1989). In the same year, red tides      Figure 7.7. Trends in saline waters closed to
                     came to North Carolina for the first time in   shellfishing in the Albemarle-Pamlico region
                     memory, causing all oystering to cease         (Pamlico, Craven, Beaufort, Hyde, Dare, and
                     just one week after the season had opened.     part of Carteret Counties). Dataprovided by
                     Finally, like other fisheries, the oyster      N.C. Division of Health Services, Shellfish
                                                                    Sanitation Program.

                           Trends In the Sound's FIsherles                                                               115

                           only three-tenths of a bushel of oysters for      mainland, there were few roads near the
                           each bushel of seed oysters and shell             sounds. It was 1919 before the first
                           planted. Thus, it was concluded that "the         automobile reached the Outer Banks. In
                           present oyster rehabilitation program             the late 1920s, a hard-surfaced road was
                           cannot improve oyster production and              built on Roanoke Island and a toll bridge
                           probably cannot even prevent further              was built to connect the island with Nags
                           decline in the industry" (Godwin et al.           Head, on Bodie Island. However, there
                           1971).                                            was no bridge linkingRoanoke Island with
                              Nevertheless, the Oyster Rehabilita-           the mainland. About 1930, the state began
                           tion Program has been continued. The              a road and bridge program that would
                           quantities of shell planted increased from        gradually link the entire region. By 1940,
                           around 100 thousand bushels in the late           theAlbemarle Soundarea was crisscrossed
                           1970s to an average of about 300 thousand         with paved roads and linked by bridges,
                           bushels peryear by the mid- 1980s. A 1984         but the Banks remained inaccessible to
                           report predicted that the outlook for the         automobile traffic. AfterWorldWarII,the
                           oyster fishery was good, based on the             state built a paved road between Oregon
                           Division's strong commitment to a large           Inlet and Hatteras Village. RoanokeIsland
                           scale cultch planting and relaying pro-           was finally linked to the mainland by a
                           grain (North Carolina Division of Marine          bridge completed in 1963 (Johnson et al.
                           Fisheries 1984). One Division official re-        1986), and later another bridge was opened
                           cently estimated that this activity increases     to traffic between Kitty Hawk and the
                           the oyster harvest by 50% in North Caro-          mainland. Since then, a fourth bridge link
                           lina.                                             has been built, connecting Bodie Island
                                                                             (Nags Head, Kitty Hawk, and Kill Devil
                           Recreational Fisheries                            Hills) with Hatteras Island to the south.
                               By the mid-1800s, recreational fishing        Today, the barrier islands southofHatteras
                           had attained the status of a recognized           still have no bridge links to the mainland,
                           sport in coastal North Carolina. Most of          but the state operates a regular (car-
                           the fishing was in the rivers, creeks and         carrying) ferry schedule between Hatteras
                           lakes, but sound waters, and even the             and Ocracoke and between Ocracoke and
                           ocean, were becoming increasingly                 Swan Quarter and Cedar Island.
                           attractive. In 1838, the first hotel at Nags          Accessibility by automobile spurred
                           Head on the Outer Banks was completed,            rapid growth of recreation on the Outer
                           and by the 1850s, there were cottages             Banks. By 1957, tourism had replaced
                           belonging to non-residents on the banks.          commercial fishing as the number one
                           BytheCivilWar, itwas popular forplanters          industry in Dare County. In 1940, there
                           and businessmen from eastern North                were no motels in Hatteras Village or on
                           Carolina to take their families to the Outer      Roanoke Island and only two at Nag's
                           Banks duringthe summer months (Johnson            Head. By 1955, there were 15 hotels, 60
                           et al. 1986; Stick 1958).                         motels, and approximately 500 rental
                               But the growth of sport fishing in the        cottages in Dare County. Duringthe 1970s,
                           region - particularly on the Outer Banks          Dare County's growth rate exceeded the
                           - was slow in the early 20th century,             state average rate by almost 6 times, and
                           because the area was so isolated and              between 1971 and 1986, travel and tourism
                           inaccessible. Until well into the century,        revenues in the county increased from $11
                           water transportation was the only way to          million to over $340 million, making Dare
                           reach the Outer Banks. And even on the            the states' leader in the tourism industry

                     116                                                                            Chapter 7
                     (Brower et al. 1989).                          1970s. The estimated harvest has ranged
                         Obviously then, there is indirect          from a high of 65,399 fish in 1971 to only
                     evidence that recreational fishing in the      3,131 fish in 1985 (Figure 7.4). The catch
                     Albemarle-Pamlico system has grown,            per unit effort for 1981, 1982 and 1983
                     especially since World War 11. Today, the      were the lowest on record for the 28-year
                     recreational fisheries are an important        period of record. However, as Hassler and
                     component of the overall fishery harvest.      Taylor (1984) noted in their analysis of
                     In fact, for a number of important species,    these data, it should be noted that striped
                     the recreational harvest probably exceeds      bass size limits and creel limits were
                     the commercial harvest. Some of these          changed in 1981. Also, bow netting and
                     species are bluefish, spotted scatroot, red    fight netting were eliminated in that year.
                     drum, and Spanish mackerel. The North          The new and more restrictive regulations
                     Carolina Division of Marine Fisheries          were responsible for some part of the
                     (DMF)began collectingdataon recreational       decreased catches and catches per unit
                     landings in 1987.                              effort.
                         Unfortunately, however, there is no            In fact, since 1980, the regulations on
                     long-term record of catch, or any direct       both commercial and sport harvesting of
                     measure of effort, for the important           striped bass have become more and more
                     recreational fish species, with one            restrictive, in an effort by the North
                     exception. Beginningin 1956, W.W. Hassler      Carolina Division of Marine Fisheries and
                     and his colleagues conducted studies to        the Wildlife Resources Commission to
                     provide long-term information on the status    preserve the Roanoke striped bass stock.
                     and abundance of striped bass in the           Manooch and Rulifson (1989) presented a
                     Roanoke River and Albemarle Sound. Sport       summary table showing a total of 42
                     catch and effort data for striped bass in the  regulation changes between 1979 and 1988
                     Roanoke River were tabulated over a 140-       concerning striped bass fishing. Included
                     mile area from the mouth of the river to the   were many new regulations that would
                     Roanoke Rapids dam. Most years, about          tend to decrease the recreational catch,
                     75% of the total striped bass catch was        such as increased minimum size limits,
                     made in the area just below the dam, and       creel limits, shortened seasons and the
                     about 25% in downstream locations.             elimination of some gear types.
                         The recreational striped bass catch,       Environmental factors that may be
                     like the commercial catch, had generally       affecting the Roanoke striped bass have
                     declined in the Roanoke since the early        been discussed above.

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                       Appendices                                                                                133

                       Appendices

                       Appendix 1. 1. Population of North Carolina and Virginia counties in the Albemarle-
                       Pamlico basin. The total population figures given for the individual sub-basins have been
                       adjusted (i.e., reduced) according to the percentage of the county land areas within the AN
                       watershed.

                       County          State      1790      1800      1810      1820      1830      1840      1850

                       Beaufort        NC       5,462     6,242     7,203     9,850    10,969    12,225    13,816
                       Bertie          NC      12,606    11,249    11,218    10,805    12,262    12,175    12,851
                       Camden          NC       4,033     4,191     5,347     6,347     6,733     5,663     6,049
                       Carteret        NC       3,732     4,399     4,823     5,609     6,597     6,591     6,939
                       Caswell         NC      10,096     8,701    11,757    13,253    15,185    14,693    15,269
                       Chowan          NC       5,011     5,132     5,297     6,464     6,697:    6,690     6,721
                       Craven          NC      10,469    10,245    12,676    13,394    13,734    13,438    14,709
                       Currituck       NC       5,219     6,928     6,985     8,098     7,655     6,073     7,236
                       Dare            NC
                       Durham          NC
                       Edgecombe       NC      10,255    10,421    12,423    13,276    14,935    15,708    17,189
                       Forsyth         NC                                                                  11,168
                       Franklin        NC       7,559     8,529    10,166     9,741    10,665    10,980    11,713
                       Gates           NC       5,392     5,881     5,965     6,837     7,866     8,161     8,426
                       Granville       NC      10,982    14,015    15,476    18,222    19,355    18,187    21,249
                       Greene          NC       6,893     4,128     4,867     4,533     6,413     6,595     6,169
                       Guilford        NC       7,191     9,442    11,420    14,511    18,737    19,175    19,754
                       Halifax         NC      13,965    13,945    13,620    17,237    17,739    16,865    16,589
                       Hertford        NC       5,828     6,701     6,052     7,712     8,537     7,484     8,142
                       Hyde            NC       4,120     4,829     6,029     4,967     6,184     6,458     7,636
                       Johnston        NC       5,634     6,301     6,867     9,607    10,938    10,599    13,726
                       Jones           NC       4,822     4,339     4,968     5,216     5,608     4,945     5,038
                       Lenoir          NC                 4,005     5,572     6,799     7,723     7,605     7,828
                       Martin          NC       6,080     5,629     5,987     6,320     8,539     7,637     8,307
                       Nash            NC       7,393     6,975     7,268     8,185     8,490     9,047    10,657
                       Northampton     NC       9,981    12,353    13,082    13,242    13,391    13,369    13,335
                       onslow          NC       5,387     5,623     6,669     7,016     7,814     7,527     8,283
                       Orange          NC      12,216    16,362    20,135    23,492    23,908    24,356    17,055
                       Pamlico         NC
                       Pasquotank      NC       5,497     5,379     7,674     8,008     8,641     8,514     8,950
                       Perquimans      NC       5,440     5,708     6,052     6,587     7,419     7,346     7,332
                       Person          NC                 6,402     6,642     9,029    10,027     9,790    10,781

                    134                                                                      Appendices

                    Appendix 1.1. Continued

                    County         State     1790      1800     1810     1820      1830     1840     1850

                    Pitt           NC      8,275     9,084    9,169   10,001    12,093   11,806   13,397
                    Rockingham     NC      6,187     8,277   10,316   11,474    12,935   13,442   14,495
                    Stokes         NC      8,528   11,026    11,645   14,033    16,196   16,265     9,206
                    Surry          NC      7,191     9,805   10,366   12,320    14,504   15,079   18,443
                    Tyrrell        NC      4,744     3,395    3,364    4,319     4,732    4,657     5,113
                    Vance          NC
                    Wake           NC     10,192   13,437    17,086   20,102    20,398   21,118   24,888
                    Warren         NC      9,207   11,284    11,004   11,158    11,887   12,919   13,912
                    Washington     NC                2,422    3,464    3,986     4,552    4,525     5,664
                    Wayne          NC      6,133     6,772    8,687    9,040    10,331   10,891   13,486
                    Wilson         NC
                    Appomattox     VA                                                               9,193
                    Bedford        VA     10,531   14,125    16,148   19,305    20,246   20,203   24,080
                    Botetourt      VA     10,524   10,427    13,301   13,589    16,354   11,679   14,908
                    Brunswick      VA     12,827   16,339    15,411   16,687    15,767   14,346   13,894
                    Campbell       VA      7,685     9,866   11,001   16,569    20,350   21,030   23,245
                    Charlotte      VA     10,078   11,912    13,161   13,290    15,252   14,595   13,955
                    Dinwiddie      VA     13,934   15,374    18,190   20,482    21,901   22,558   25,118
                    Floyd          VA                                                     4,453     6,458
                    Franklin       VA      6,842     9,302   10,724   12,017    14,911   15,832   17,430
                    Greensville    VA      6,362     6,727    6,853    6,858     7,117    6,366     5,639
                    Halifax        VA     14,722   19,377    22,133   19,060    28,034.  25,936   25,962
                    Henry          VA      8,479     5,259    5,611    5,624     7,100    7,335     8,872
                    Isle of  WightVA       9,028     9,342    9,186   10,139    10,517    9,972     9,353
                    Lunenburg      VA      8,959   10,381    12,265   10,662    11,957   11,055   11,692
                    Mecklenberg    VA     14,733   17,008    18,453   19,786    20,477   20,724   20,630
                    Montgomery     VA     13,228     9,044    8,409    8,733    12,306    7,405     8,359
                    Mottoway       VA                9,401    9,278    9,658    10,130    9,719     8,437
                    Patrick        VA                4,331    4,695    5,089     7,395    8,032     9,609
                    Pittsylvania   VA     11,579   12,697    17,172   21,232    26,034   26,398   28,796
                    Prince GeorgeVA        8,173     7,425    8,050    8,030     8,367    7,175     7,596
                    Roanoke        VA                                                     5,499     8,477
                    Southampton VA        12,864   13,925    13,497   14,170    16,074   14,525   13,521
                    Surry          VA      6,227     6,535    6,885    6,594     7,109    6,480     5,679
                    Sussex         VA     10,549   11,062    11,362   11,884    12,720   11,229     �,820
                    Total                449,134   519,415   579,126  640,248  720,507   711,144 772,244

                    Chowan  River        100,869   116,649   120,885  127,550  135,533   127,832 127,015
                    Roanoke River        139,952   164,236   184,885  204,916  242,690   244,086 263,537
                    Albemarle Sound       29,127   31,495    36,252   40,902    43,668   40,853   44,275
                    Tar-Pamlico R.        53,033   58,541    64,036   71,628    78,866   80,797   89,025
                    Meuse River           56,851   66,869    80,183   91,520    99,888   99,937  108,301
                    Pamlico sound          2,296     2,691    3,340    2,801     3,475    3,620     4,255

                      Appendices                                                                     135
                      Appendix 1.1. Continued

                      County        State      1860     1870       1880       1890       1900

                      Beaufort      NC      14,766   13,011     17,474     21,072     26,404
                      Bertie        NC      14,310   12,950     16,399     19,176     20,538
                      Camden        NC       5,343    5,361      6,274      5,667      5,474
                      Carteret      NC       8,186    9,010      9,784     10,825     11,811
                      Caswell       NC      16,215   16,081     17,825     16,028     15,028
                      Chowan        NC       6,842    6,450      7,900      9,167     10,258
                      Craven        NC      16,268   20,516     19,729     20,533     24,160
                      Currituck     NC       7,415    5,131      6,476      6,747      6,529
                      Dare          NC                2,778      3,243      3,768      4,757
                      Durham        NC                                     18,041     26,233
                      Edgecombe     NC      17,376   22,970     26,181     24,113     26,591
                      Forsyth       NC      12,692   13,050     18,070     28,434     35,261
                      Franklin      NC      14,107   14,134     29,829     21,090     25,116
                      Gates         NC       8,443    7,724      8,897     10,254     10,413
                      Granville     NC      23,396   24,831     31,286     24,484     23,263
                      Greene        NC       7,925    8,687     10,037     10,039     12,038
                      Guilford      NC      29,056   21,736     23,585     28,052     39,074
                      Halifax       NC      19,442   29,408     30,300     28,908     30,793
                      Hertford      NC       9,504    9,273     11,843     13,851     14,294
                      Hyde ,        NC       7,732    6,445      7,765      8,903      9,278
                      Johnston      NC      15,656   16,897     23,461     27,239     32,250
                      Jones         NC       5,730    5,002      7,491      7,403      8,226
                      Lenoir        NC      10,220   10,434     15,344     14,879     18,639
                      Martin        NC      10,195    9,647     13,140     15,221     15,383
                      Nash          NC      11,687   11,077     17,731     20,707     25,478
                      Northampton   NC      13,372   14,749     20,032     21,242     21,150
                      Onslow        NC       8,856    7,569      9,829     10,303     11,940
                      Orange        NC      16,947   17,507     23,689     14,948     14,690
                      Pamlico       NC                           6,323      7,146      8,045
                      Pasquotank    NC       8,940    8,131     10,369     10,748     13,660
                      Perquimans    NC       7,238    7,945      9,466      9,293     10,091
                      Person        NC      11,221   11,170     13,719     15,151     16,685
                      Pitt          NC      16,080   17,376     21,794     25,519     30,889
                      Rockingham    NC      16,746   15,708     21,744     25,363     33,163
                      Stokes        NC      10,402   11,208     15,353     17,199     19,866
                      Surry         NC      10,380   11,252     15,302     19,282     25,515
                      Tyrrell       NC       4,944    4,173      4,545      4,225      4,980
                      Vance         NC                                     17,581     16,684
                      Wake          NC      28,627   35,617     47,939     49,207     54,626
                      Warren        NC      15,726   17,768     22,619     19,360     19,151
                      Washington    NC       6,357    6,516      8,928     10,200     10,608
                      Wayne         NC      14,905   18,144     24,951     26,100     31,356
                      Wilson        NC       9,720   12,258     16,064     18,644     23,596
                      Appomattox    VA       8,889    8,950     10,080      9,589      9,662
                      Bedford       VA      25,068   25,327     31,205     31,213     30,356
                      Botetourt     VA      11,516   11,329     14,809     14,854     17,161

                  136                                                                  Appendices

                  Appendix 1.1. Continued

                  County         State      1860    1870       1880       1890       1900

                  Brunswick      VA     14,809   13,427     16,707     17,245     18,217
                  Campbell       VA     26,197   28,384     36,250     41,087     23,256
                  Charlotte      VA     14,471   14,513     16,653     15,077     15,343
                  Dinwiddie      VA     30,198   30,702     32,870     13,515     15,374
                  Floyd          VA       8,236   9,824     13,255     14,405     15,388
                  Franklin       VA     20,098   18,364     25,084     24,985     25,953
                  Greensville    VA       6,374   6,362       8,407     8,230       9,758
                  Halifax        VA     26,520   27,828     23,588     34,424     37,197
                  Henry          VA     12,105   12,303     16,009     18,208     19,265
                  Isle of  WightVA        9,977   8,320     10,572     11,313     13,102
                  Lunenburg      VA     11,983   10,403     11,535     11,372     11,705
                  Mecklenberg    VA     20,096   21,318     24,610     25,359     26,551
                  Montgomery     VA     10,617   12,556     16,693     17,742     15,852
                  Nottoway       VA       8,836   9,291     11,156     11,582     12,366
                  Patrick        VA       9,359  10,161     12,833     14,147     15,403
                  Pittsylvania   VA     32,104   31,343     52,589     50,941     46,894
                  Prince GeorgeVA         8,411   7,820     10,054      7,872       7,752
                  Roanoke        VA       8,048   9,350     13,105     30,101     15,837
                  Southampton VA        12,915   12,285     18,012     20,078     22,848
                  Surry          VA       6,133   5,585       7,391     8,256       8,469
                  Sussex         VA     10,175    7,885     10,062     11,100     12,082
                  Total                846,102  873,324   1,116,259  1,198,807  1,289,775

                  Chowan  River        136,252  129,470    159,100    149,971    161,296
                  Roanoke River        286,223  295,286    373,454    421,261    407,307
                  Albemarle Sound       43,965   41,908     51,105     52,768     58,159
                  Tar-Pamlico R.       100,488  112,434    150,083    152,551    171,460
                  Neuse River          131,542  149,205    197,858    215,333    254,546
                  Pamlico Sound           4,344   4,853       8,490     9,699     10,729

                      Appendices                                                                    137
                      Appendix 1.1. Continued

                      County       State         1910       1920      1930       1940

                      Beaufort      NC        30,877     31,024    35,026     36,431
                      Bertie        NC        23,039     23,993    25,844     26,201
                      Camden        NC         5,640      5,382     5,461      5,440
                      Carteret      NC        13,776     15,384    16,900     18,284
                      Caswell       NC        14,858     15,759    18,214     20,032
                      Chowan        NC        11,303     10,649    11,282     11,572
                      Craven        NC        25,594     29,048    30,685     31,298
                      Currituck     NC         7,693      7,268     6,710      6,709
                      Dare          NC         4,841      5,115     5,202      6,041
                      Durham        NC        35,276     42,219    67,196     80,244
                      Edgecombe     NC        32,101     37,995    47,894     49,162
                      Forsyth       NC        47,311     77,269    111,681    126,475
                      Franklin      NC        24,692     26,667    29,456     30,382
                      Gates         NC        10,455     10,537    10,551     10,060
                      Granville     NC        25,102     26,846    28,723     29,344
                      Greene        NC        13,083     16,212    18,656     18,548
                      Guilford      NC        60,497     79,272    133,010    153,916
                      Halifax       NC        37,646     43,766    53,246     56,512
                      Hertford      NC        15,436     16,294    17,542     19,352
                      Hyde          NC         8,840      8,386     8,550      7,860
                      Johnston      NC        41,401     48,998    57,621     63,798
                      Jones         NC         8,721      9,912    10,428     10,926
                      Lenoir        NC        22,769     29,555    35,716     41,211
                      Martin        NC        17,797     20,838    23,400     26,111
                      Nash          NC        33,727     41,061    52,782     55,608
                      Northampton   NC        22,232     23,184    27,161     28,299
                      Onslow        NC        14,125     14,703    15,289     17,939
                      orange        NC        15,064     17,895    21,171     23,072
                      Pamlico       NC         9,966      9,060     9,299      9,706
                      Pasquotank    NC        16,693     17,670    19,143     20,568
                      Perquimans    NC        11,054     11,137    10,668      9,773
                      Person        NC        17,356     18,973    22,039     25,029
                      Pitt          NC        36,340     45,569    54,466     61,244
                      Rockingham    NC        36,442     44,149    51,083     57,898
                      Stokes        NC        20,151     20,575    22,290     22,656
                      Surry         NC        29,705     32,464    39,749     41,783
                      Tyrrell       NC         5,219      4,849     5,164      5,556
                      Vance         NC        19,425     22,799    27,294     29,961
                      Wake          NC        63,229     75,155    94,757     109,544
                      Warren        NC        20,266     21,593    23,364     23,145
                      Washington    NC        11,062     11,429    11,603     12,323
                      Wayne         NC        35,698     43,640    53,013     58,328
                      Wilson        NC        28,269     36,813    44,914     50,219
                      Appomattox    VA         8,904      9,255     8,402      9,020
                      Bedford       VA        29,549     30,669    29,091     29,687
                      Botetourt     VA        17,727     16,557    15,457     16,447

                   138                                                                  Appendices

                   Appendix I. I. Continued

                   County       State         1910       1920       1930       1940

                   Brunswick     VA        19,244     21,025     20,486     19,575
                   Campbell      VA        23,043     26,716     22,885     26,048
                   Charlotte     VA        15,785     17,540     16,061     15,861
                   Dinwiddie     VA        15,442     17,949     18,492     18,166
                   Floyd         VA        14,092     13,115     11,698     11,967
                   Franklin      VA        26,480     26,283     24,337     25,864
                   Greensville   VA        11,890     11,606     13,388     14,866
                   Halifax       VA        40,044     41,374     41,283     41,271
                   Henry         VA        18,459     29,238     20,088     26,481
                   Isle of WightVA         14,929     14,433     13,409     13,381
                   Lunenburg     VA        12,780     15,260     14,058     13,844
                   Mecklenberg   VA        28,956     31,208     32,622     31,933
                   Montgomery    VA        17,268     18,595     19,605     21,206
                   Nottoway      VA        13,462     14,161     14,866     15,556
                   Patrick       VA        17,195     16,850     15,787     16,613
                   Pittsylvania  VA        50,709     56,493     61,424     61,697
                   Prince GeorgeVA           7,848    12,915     10,311     12,226
                   Roanoke       VA        19,623     22,395     35,289     42,897
                   Southampton VA          26,302     27,555     26,870     26,442
                   Surry         VA          9,715      9,305      7,096      6,193
                   Sussex        VA        13,664     12,834     12,100     12,485
                   Total                1,457,881   1,664,437  1,919,348  2,078,286

                   Chowan River           176,392    187,148    188,454    191,659
                   Roanoke River          437,061    491,723    525,304    564,084
                   Albemarle.Sound         64,365     64,446     65,729     67,371
                   Tar-Pamlico R.         198,375    225,741    267,433    281,927
                   Neuse River            299,103    358,655    438,650    488,704
                   Pamlico Sound           11,417     10,950     11,222     11,425

                      Appendices                                                                      139
                      Appendix 1.1. Continued

                      County      State          1950       1960       1970       1980       1987

                      Beaufort       NC       37,134     36,014     35,980     40,355     45,000
                      Bertie         NC       26,439     24,350     20,528     21,024     22,000
                      Camden         NC        5,223      5,598      5,453      5,829      6,000
                      Carteret       NC       23,059     30,940     31,603     41,092     52,000
                      Caswell        NC       20,870     19,912     19,055     20,705     22,000
                      Chowan         NC       12,540     11,729     10,764     12,558     13,000
                      Craven         NC       48,823     58,733     62,554     71,043     83,000
                      Currituck      NC        6,201      6,601      6,976     11,089     13,000
                      Dare           NC        5,405      5,935      6,995     13,377     18,000
                      Durham         NC      101,639    111,995    132,681    152,785    166,000
                      Edgecombe      NC       51,634     54,226     54,226     55,988     59,000
                      Forsyth        NC      146,135    189,428    215,118    243,683    262,000
                      Franklin       NC       31,341     28,755     26,820     30,055     33,000
                      Gates          NC        9,555      9,254      8,524      8,875      9,000
                      Granville      NC       31,793     33,110     32,762     34,043     37,000
                      Greene         NC       18,024     16,741     14,967     16,117     17,000
                      Guilford       NC      191,057    246,520    288,645    317,154    328,000
                      Halifax        NC       58,377     58,956     53,884     55,286     56,000
                      Hertford       NC       21,453     22,718     23,529     23,368     24,000
                      Hyde           NC        6,479      5,765      5,571      5,873      8,900
                      Johnston       NC       65,906     62,936     61,737     70,599     79,000
                      Jones          NC       11,004     11,005      9,779      9,705     10,000
                      Lenoir         NC       45,953     55,276     55,204     59,819     60,000
                      Martin         NC       27,938     27,139     24,730     25,948     26,000
                      Nash           NC       59,919     61,002     59,122     67,153     72,000
                      Northampton    NC       28,432     26,811     23,099     22,584     22,000
                      Onslow         NC       42,047     82,706    103,126    112,784    129,000
                      Orange         NC       34,435     42,970     57,567     77,055     84,000
                      Pamlico        NC        9,993      9,850      9,467     10,398     11,000
                      Pasquotank     NC       24,347     25,630     26,824     28,462     29,000
                      Perquimans     NC        9,602      9,178      8,351      9,486     11,000
                      Person         NC       24,361     26,394     25,914     29,164     31,000
                      Pitt           NC       63,789     69,942     73,900     90,146     99,000
                      Rockingham     NC       64,816     69,629     72,402     83,426     86,000
                      Stokes         NC       21,520     22,314     23,782     33,086     36,000
                      Surry          NC       45,593     48,205     51,415     59,449     62,000
                      Tyrrell        NC        5,048      4,520      3,806      3,975      4,000
                      Vance          NC       32,101     32,002     32,691     36,748     39,000
                      Wake           NC      136,450    169,082    229,006    301,327    371,000
                      Warren         NC       23,539     19,652     15,810     16,232     17,000
                      Washington     NC       13,180     13,488     14,038     14,801     14,000
                      Wayne          NC       64,267     82,059     85,408     97,054    100,000
                      Wilson         NC       54,506     57,716     57,486     63,132     65,000
                      Appomattox     VA        8,764      9,148      9,784     11,971     13,000
                      Bedford        VA       29,627     31,028     26,728     34,927     40,000
                      Botetourt,     VA       15,766     16,715     18,193     23,270     25,000

                  140                                                                    Appendices

                  Appendix 1.1. Continued

                  County      State          1950       1960       1970        1980       1987

                  Brunswick     VA        20,136     17,779     16,172      15,632     16,000
                  Campbell      VA        28,877     32,958     34,248      45,424     49,000
                  Charlotte     VA        14,057     13,368     12,366      12,266     12,000
                  Dinwiddie     VA        18,839     22,183     21,668      22,602     22,000
                  Floyd         VA        11,251     10,462       9,775     11,563     12,000
                  Franklin      VA        24,560     25,925     28,163      35,740     38,000
                  Greensville   VA        16,319     16,155       9,604     10,903     11,000.
                  Halifax       VA        41,442     33,637     30,076      30,599     30,000
                  Henry         VA        31,219     40,335     50,901      57,654     58,000
                  Isle of  wightvA        14,906     17,164     18,285      21,603     24,000
                  Lunenburg     VA        14,116     12,523     11,687      12,124     12,000
                  Mecklenberg   VA        33,497     31,428     29,426      29,444     30,000
                  Montgomery    VA        29,780     32,923     47,157      63,516     69,000
                  Nottoway      VA        15,479     15,141     14,260      14,666     14,000
                  Patrick       VA        15,642     15,282     15,282      17,647     18,000
                  Pittsylvania  VA        66,096     58,296     58,789      66,147     68,000
                  Prince GeorgeVA         19,697     20,270     24,371      25,733     27,000
                  Roanoke       VA        41,486     61,693     53,817      72,945     78,000
                  Southampton VA          26,522     27,195     18,582      18,731     19,000
                  Surry         VA          6,220      6,220      5,882       6,046      6,000
                  Sussex        VA        12,785     12,411     11,464      10,874     10,000
                  Total                2,319,010   2,587,025  2,757,979  3,174,859   3,431,900

                  Chowan  River          202,199    201,504    180,563     185,925    187,500
                  Roanoke River          591,367    622,439    627,608     728,357    763,470
                  Albemarle Sound         69,813     70,856     71,045      83,398     90,595
                  Tar-Pamlico R.         294,867    297,327    290,695     319,906    342,664
                  Neuse River            568,141    645,904    721,831     858,542    964,740
                  Pamlico Sound           10,693     10,712     10,909      14,435     18,567

                     Appendices                                                                     141
                     A p p e n d ix 3. 1 . County land areas in five major sub-basins of the
                     Albemarle/Pamlico Estuarine system watershed. "Percent of County Area" is the
                     value used to adjust county totals (for population, agricultural acreages and yields,
                     and all other non-point source variables) to give estimates of the county's
                     contribution to the basin

                                         County Area (sq. m.)     Land Area in Basin

                     County        state    Land   Water    Sum       Square   Percent
                                                                      Miles    of C. Area

                     CHOWAN  RIVER
                     Bertie          MC     698       33    731          170     24.4
                     Brunswick       VA     563                          518     92.0
                     Chowan          MC     172       57    230          110     63.9
                     Dinwiddie       VA     507                          466     92.0
                     Gates           MC     337        7    344          252     74.8
                     Greensville     VA     300                          300    100.0
                     Hertford        NC     353        6    359          353    100.0
                     Isle of Wight   VA     319                          160     50.0
                     Lunenburg       VA     432                          432    100.0
                     Mecklenberg     VA     616                          105     17.0
                     Northampton     NC     547             547          357     65.3
                     Nottoway        VA     316                          167     53.0
                     Prince George   VA     266                          136     51.0
                     Southampton     VA     603                          603    100.0
                     Suffolk City    VA     409                          123     30.0
                     Surry           VA     281                          169     60.0
                     Sussex          VA     491                          491    100.0
                     TOTAL                 7,210                       4,911

                     ROANOKE RIVER
                     Appomattox      VA     336                          95      28.4
                     Beaufort        NC     826      135    961             8     1.0
                     Bedford         VA     747                          641     85.8
                     Bertie          NC     698       33    731          518     74.2
                     Botetourt       VA     545                          71      13.1
                     Brunswick       VA     563                          45       8.0
                     Campbell        VA     505                          427     84.6
                     Caswell         NC     428             428          383     89.5
                     Charlotte       VA     477                          477    100.0
                     Floyd           VA     381                          31       8.2
                     Forsyth         NC     419             419          124     29.6
                     Franklin        VA     683                          683    100.0
                     Granville       NC     544             544          186     34.2
                     Guilford        NC     657             657          12       1.8
                     Halifax         NC     742             742          302     40.7
                     Halifax         VA     816                          816    100.0
                     Henry           VA     382                          382    100.0
                     Martin          NC     462             462          342     74.0
                     Mecklenburg     VA     616                          511     83.0
                     Montgomery      VA     390                          168     43.0

                  142                                                                 Appendices

                  Appendix 3. 1. Continued

                                     County Area (sq. m.)     Land Area in Basin

                  County       State    Land   Water    Sum       Square   Percent
                                                                  Miles   of C. Area

                  Northampton    NC      547            547          190      34.7
                  Orange         NC      400            400            7       1.8
                  Patrick        VA      481                         425      88.3
                  Person         NC      401            401          250      62.3
                  Pittsylvania   VA      995                         995     100.0
                  Roanoke        VA      251                         228      90.8
                  Rockingham     NC      569            569          476      83.7
                  Stokes         NC      457            457          386      84.5
                  Surry          NC      536            536            15      2.8
                  Vance          NC      269            269          145      53.9
                  Warren         NC      441            441          171      38.8
                  Washington     NC      343      85    428            56     16.3
                  TOTAL               16,907                        9,567

                  TAR-PAMLICO
                  Beaufort       NC      826    135     961          776      93.9
                  Edgecombe      NC      511            511          511     100.0
                  Franklin       NC      494            494          426      86.2
                  Granville      NC      544            544          220      40.4
                  Halifax        NC      742            742          440      59.3
                  Hyde           NC      613    736 1,349            159      25.9
                  Martin         NC      462            462          120      26.0
                  Nash           NC      544            544          402      73.9
                  Pamlico        NC      338    228     566            27      8.0
                  Person         NC      401            401            32      8.0
                  Pitt           NC      655            655          372      56.8
                  Vance          NC      269            269          124      46.1
                  Warren         NC      441            441          270      61.2
                  Washington     NC      343      85    428            89     25.9
                  Wilson         NC      375            375            63     16.8
                  TOTAL                7,558                        4,031

                  NEUSE RIVER
                  Beaufort       NC      826    135     961            43      5.2
                  Carteret       NC      536    532    1,068.        ill      20.7
                  Craven         NC      699       60   759          643      92.0
                  Durham         NC      299            299          216      72.2
                  Franklin       NC      494            494            65     13.2
                  Granville      NC      544            544          138      25.4
                  Greene         NC      269            269          269     100.0
                  Johnston       NC      793            793          793     100.0
                  Jones          NC      468            468          369      78.8
                  Lenoir         NC      400            400          400     100.0
                  Nash           NC      544            544          142      26.1
                  Orange         NC      400            400          209      52.3

                         Appendices                                                                                143
                         Appendix 3. 1. Continued

                                               County Area (sq. m.)         Land Area in Basin

                         County         state      Land   Water      Sum        Square    Percent
                                                                               Miles      of C. Area

                         Pamlico           NC      338      228      566            165      48.9
                         Person            NC      401               401            119      29.7
                         Pitt              NC      655               655            283      43.2
                         Wake              NC      859               859            723      84.2
                         Wayne             NC      557               557            520      93.4
                         Wilson            NC      375               375            312      83.2
                         TOTAL                    9,457                           5,520

                         COASTAL
                         Albemarle Sound
                         Bertie            NC      698       33      731             10        1.4
                         Camden            NC      239       77      316            239     100.0
                         Chowan            NC      172       57      230             62      36.1
                         Currituck         NC      246      177      423            246     100.0
                         Dare              NC      391      880   1,271             225      57.6
                         Gates             NC      337         7     344             85      25.2
                         Hyde              NC      613      736   1,349             128      20.9
                         Pasquotank        NC      228       65      293            228     100.0
                         Perquimans        NC      246       89      335            246     100.0
                         Tyrrell           NC      390      169      559            390     100.0
                         Washington        NC      343       85      428            198      57.8
                         TOTAL                    3,903                           2,057
                         Pamlico Sound
                         Carteret          NC      536      532   1,068              15         2.8
                         Dare              NC      391      880   1,271             167      42.4
                         Hyde              NC      613      736   1,349             326      53.2
                         Pamlico           NC      338      228      566            145      42.9
                         TOTAL                    1,877                             653

                         Notes:
                         a. Area south of 35' latitude (i.e., Core and Bogue Sounds) excluded from Coastal sub-
                         basin
                         b. Pamlico-Albemarle boundary is a line running east-west through Manteo, N.C.
                         c. Tar-Pamlico River estuary basin includes all coastal drainage west of the mouth of the
                         estuary. The boundary between Tar-Pamlico and Pamlico Sound (Coastal) corresponds
                         to the eastern edge of USGS cataloging unit 03020104 (see maps in NOAA National
                         Estuarine Atlas for identification of these units (NOAA 1985)).
                         d. The southern boundary of Pamlico Sound is a line between Hog Island and Swash Inlet
                         (southwest of this line is Core Sound) - Note that NOAA National Estuarine Atlas has
                         this boundary farther southwest, at a line between Marshallberg and Core Banks.
                         e. The boundary between Chowan River Basin and Albemarle Sound is mouth of
                         Chowan River near Edenton, corresponding to boundary between USGS cataloging units
                         03010203 and 03010205.

                  144                                                                     Appendices

                  Appendix 3.1 Continued

                  f. Albemarle Sound corresponds to USGS cataloging unit 03010205.
                  g. Pamlico Sound corresponds to USGS cataloging unit 03020105.
                  h. Eastern boundary of Neuse River basin = boundary between USGS cataloging units
                  03020204 and 03020106.
                  i. Eastern boundary of Roanoke River basin boundary between USGS cataloging units
                  03010107 and 03010205.

                       Appendices                                                                      145
                       Appendix 3.2a. Acres of Land in Farms

                                               1880       1890       1900        1910       1920

                       Chowan River          2464949    2365240    2456909   2313583    2097147
                       Roanoke River         4967022    5068506    5283595   5315135    5076096
                       Albemarle Sound       666732     600988     549003    1269179    492413
                       Tar-Pamlico R.        1859608    1824614    1878555   1836714    1650105
                       Neuse River           2684615    2679392    2677646   2671131    2359364
                       Pamlico Sound         100326     93821      91390       89467      83981
                       Total Coastal         767058     694810     640393    1358646    576394
                       Total                 12743253   12632562   12937098  13495209  11759107

                                               1925       1930       1935       1940       1945

                       Chowan River          1938618    1928197    2058922   2002257    1945566
                       Roanoke River         4785518    4901548    5037644   4823633    4678175
                       Albemarle Sound       431990     446340     445547    457963     448986
                       Tar-Pamlico R.        1518034    1531564    1800901   1723753    1738125
                       Neuse River           2153428    2113459    2424232   2282723    2325327
                       Pamlico Sound         76134      69267      77256       70737      59460
                       Total Coastal         508124     515607     522803    528700     508447
                       Total                 10903722   10990375   11844502  11361065  11195640

                                               1950       1954       1959       1964       1969

                       Chowan River          2036286    1964801    1678576   1505628    1435360
                       Roanoke River         4741180    4470567    4094046   3787973    3303075
                       Albemarle sound       476410     456960     446638    430965     406375
                       Tar-Pamlico R.        1851346    1775610    1685385   1565672    1497199
                       Neuse River           2459176    2351979    2133319   1974766    1775826
                       Pamlico Sound         67413      69741      70407       66588      62602
                       Total Coastal         543823     526702     517045    497554     468977
                       Total                 11631811   11089659   10108371  9331593    8480437

                                              1974        1978       1982       1987

                       chowan River          1346248    1295363    1214301   1177872
                       Roanoke River         2841138    2752780    2655110   2575457
                       Albemarle Sound       405070     447050     469384    455303
                       Tar-Pamlico R.        1257590    1285257    1202536   1166460
                       Neuse River           1597807    1592321    1473881   1429665
                       Pamlico Sound         69163      69634      80138      77734
                       Total Coastal         474233     516684     549523    533037
                       Total                 7517017    7442404    7095350   6882489

                  146                                                                   Appendices
                  Appendix 3.2b. Acres of Harvested Cropland

                                          1880       1890       1900        1910       1920

                  Chowan River          428302                477991                529202
                  Roanoke River       1045276                 1096797              1114829
                  Albemarle Sound       174349                156921                192890
                  Tar-Pamlico R.        472982                485395                551255
                  Neuse River           628622                715262                806725
                  Pamlico sound          19829                 17983                  30145
                  Total Coastal         194178                174904                223035
                  Total               2769360                 2950347              3225045

                                          1925        1930       1935       1940       1945

                  Chowan River          514563     553523     536273     563039     578564
                  Roanoke River       1068344     1113728     1063036   1156245    1102232
                  Albemarle Sound       203374     205196     212333     214223     217026
                  Tar-Pamlico R.        589380     623476     623346     672674     646010
                  Neuse River           812425     801286     853217     919896     915909
                  Pamlico Sound          30104       28884      29498      30645      29944
                  Total Coastal         233478     234080     241831     244868     246970
                  Total               3218190     3326093     3317703   3556722    3489685

                                           1950       1954       1959       1964       1969

                  Chowan River          550976     525518     500087     444313     442954
                  Roanoke River       1009016      964181     846882     707756     592530
                  Albemarle sound       209160     216972     221581     213997     228732
                  Tar-Pamlico R.        668130     642814     607239     518450     454082
                  Neuse River           919543     897536     797235     673052     599697
                  Pamlico Sound          28070       28798      29862      29798      32049
                  Total Coastal         237231     245770     251442     243795     260781
                  Total               3384895     3275818     3002886   2587367    2350043

                                           1974       1978       1982       1987

                  chowan River          507897     521092     552496     458237
                  Roanoke River         638962     658832     693834     412340
                  Albemarle sound       271252     320775     348359     313078
                  Tar-Pamlico R.        537258     592236     618788     529547
                  Neuse River           715831     782523     808933     665532
                  Pamlico Sound          38967       44916      55826      49081
                  Total Coastal         310219     365691     404185     362159
                  Total               2710167     2920374     3078236   2427815

                      AppendIces                                                                      147
                      Appendix 3.2c. Acres of Pastureland. "E" Indicates interpolated (i.e., estimated
                      values)

                                             1880E      1890E      1900B      1910E      1920E

                      chowan River          102597     102597      10259     710259     7102597
                      Roanoke River         577820     577820     577820     577820     577820
                      Albemarle Sound        11624      11624      11624      11624      11624
                      Tar-Pamlico R.         54387      54387      54387      54387      54387
                      Neuse River            59654      59654      59654      59654      59654
                      Pamlico Sound           1772       1772       1772       1772       1772
                      Total Coastal          13397      13397      13397      13397      13397
                      Total                 807855     807855     807855     807855     807855

                                              1925       1930       1935       1940       1945

                      Chowan River          102597     119365      99317     105373     111430
                      Roanoke River         577820     604630     604854     644213     683571
                      Albemarle Sound        11624      16380      14292      14651      15010
                      Tar-Pamlico R.         54387      52271      57147      63361      69574
                      Neuse River            59654      73687      70303      79901      89500
                      Pamlico Sound           1772       2380       2918       2528       2138
                      Total Coastal          13397      18760      17210      17179      17148
                      Total                 807855     868713     848831     910027     971223

                                              1950       1954       1959       1964       1969

                      Chowan River          134737     158095     125814     122233     114944
                      Roanoke River         677105     649190     573672     585665     533586
                      Albemarle Sound        18742      30597      21423      17969      18789
                      Tar-Pamlico R.         87827     118383     101139     105367     104417
                      Neuse River           115986     137943     120729     121578     110111
                      Pamlico sound           2136       3883       4798       3087       4885
                      Total Coastal          20878      34480      26221      21056      23674
                      Total                1036534     1098091    947576     955899     886733

                                              1974       1978       1982      1987E

                      Chowan River          154561     102693     103336     103336
                      Roanoke River         566171     496487     505091     505091
                      Albemarle Sound        18420      14590      10336      10336
                      Tar-Pamlico R.        122847      91387      78804      78804
                      Neuse River           137980     106237      93067      93067
                      Pamlico Sound           5187       4294       2459       2459
                      Total coastal          23607      18884      12794      12794
                      Total                 1005165    815688     793092     793092

                   148                                                                   Appendices
                   Appendix 3.2d. Acres of "other land" in farms; generally the sum of two land
                   categories in the agriculre census reports: 1) Other Cropland (Idle, Crop Failure, etc.) and
                   2) Other Land - Not Pasture and Range (i.e., house lots, ponds, roads, etc.). Harvested
                   cropland, non-forested pastureland, and forested lands are not included in this landuse
                   category. "E" indicates values estimated by interpolation

                                             1880E      1890E      1900E      1910E      1920E

                   Chowan River             300461     300461     300461     300461     300461
                   Roanoke River            951039     951039     951039     951039     951039
                   Albemarle Sound           43533      43533      43533      43533      43533
                   Tar-Pamlico R.           196642     196642     196642     196642     196642
                   Neuse River              285889     285889     285889     285889     285889
                   Pamlico Sound             18491      18491      18491      18491      18491
                   Total                   1796054    1796054    1796054     1796054    1796054
                   Coastal                   62024      62024      62024      62024      62024

                                               1925      1930       1935       1940        1945

                   Chowan River             300461     255712     247368     170800     137025
                   Roanoke River            951039     854695     815374     638900     523509
                   Albemarle Sound           43533      41655      35929      29707      16847
                   Tar-Pamlico R.           196642     156457     182137     119154     123019
                   Neuse River              285889     232745     212408     171269     142240
                   Pamlico sound             18491       5198       8845       6327        4789
                   Total                   1796054    1546462    1502061     1136157    947429
                   Coastal                   62024      46853      44774      36034      21636

                                               1950      1954       1959       1964        1969

                   Chowan River             156098     107639     111867     124987     156938
                   Roanoke River            622008     475913     508789     492693     465201
                   Albemarle sound           36012      18343      23795      42397      44102
                   Tar-Pamlico R.           146107     113000     139261     173697     226112
                   Neuse River              194216     156896     189233     216248     301567
                   Pamlico Sound               7288      5421       6874       7548        5310
                   Total                   1161729     877212     979819     1057569    1199231
                   Coastal                   43299      23764      30669      49945      49413

                                             1974       1978       1982       1987E

                   Chowan River             98802     109107      91147       91147
                   Roanoke River           323489     376364     317112      317112
                   Albemarle Sound          27570      29476      29325       29325
                   Tar-Pamlico R.          120576     151130     107819      107819
                   Neuse River             172335     181918     132203      132203
                   Pamlico Sound             2751       4866       5013        5013
                   Total                   745523     852860     682619      682619
                   Coastal                  30322      34342      34338       34338

                      Appendices                                                                      149
                      Appendix 3.2e. Acres of Forest. "Ell Indicates interpolated (i.e., estimated) values

                                              1880E      1890E   1900B         1910E      1920E

                      Chowan River         2063556    2063556    2063556    2063556   2063556
                      Roanoke River        3375191    3375191    3375191    3375191   3375191
                      Albemarle Sound      857692     857692     857692     857692     857692
                      Tar-Pamlico R.       1342457    1342457    1342457    1342457   1342457
                      Neuse River          1914105    1914105    1914105    1914105   1914105
                      Pamlico Sound        298843     298843     298843     298843     298843
                      Total Coastal        1156535    1156535    1156535    1156535   1156535
                      Total                9851844    9851844    9851844    9851844   9851844

                                             1925E      1930E      1935E      1940       1945E

                      Chowan River         2063556    2063556    2063556    2063556   2082702
                      Roanoke River        3375191    3375191    3375191    3375191   3506594
                      Albemarle Sound      857692     857692     857692     857692     882699
                      Tar-Pamlico R.       1342457    1342457    1342457    1342457   1389694
                      Neuse River          1914105    1914105    1914105    1914105   1949371
                      Pamlico sound        298843     298843     298843     298843     302491
                      Total Coastal        1156535    1156535    1156535    1156535   1185190
                      Total                9851844    9851844    9851844    9851844   10113551

                                             1950E      1954E       1959       1964      1969E

                      Chowan River         2101848    2120994    2140140    2178594   2208389
                      Roanoke River        3637997    3769399    3900802    4021611   4008157
                      Albemarle Sound      907706     932713     957720     890980     865470
                      Tar-Pamlico R.       1436932    1484169    1531406    1527421   1508630
                      Neuse River          1984637    2019902    2055168    2060987   2032545
                      Pamlico Sound        306139     309787     313435     281047     277998
                      Total Coastal        1213845    1242500    1271155    1172027   1143468
                      Total               10375258   10636964    10898671  10960640   10901189

                                              1974      1978E       1982       1987

                      chowan River         2238184    2166571    2094957    2094957
                      Roanoke River        3994704    3929931    3865158    3865158
                      Albemarle Sound      839960     773923     707887     707887
                      Tar-Pamlico R.       1489839    1444911    1399982    1399982
                      Neuse River          2004102    1952878    1901654    1901654
                      Pamlico Sound        274949     260658     246366     246366
                      Total Coastal        1114909    1034581    954253     954253
                      Total               10841738   10528871    10216003  10216003

                  150                                                                  Appendices
                  Appendix 3.2f. Acres of Urban Land. "E" Indicates interpolated (i.e., estimated) values

                                        1880B      1890E      1900E      1910B      1920E

                  Chowan River                0          0         0          0          0
                  Roanoke River               0          0         0          0          0
                  Albemarle sound             0          0         0          0          0
                  Tar-Pamlico R.              0          0         0          0          0
                  Neuse River                 0          0         0          0          0
                  Pamlico sound               0          0         0          0          0
                  Total Coastal               0          0         0          0          0
                  Total                       0          0         0          0          0

                                        1925E      1930E      1935E       1940      1945E

                  chowan River                0          0         0          0          0
                  Roanoke River               0      2000      5000      10240      16000
                  Albemarle Sound             0          0         0'         0          0
                  Tar-Pamlico R.              0      1000      2000       3840       3840
                  Neuse River                 0      3000      7000      13440      14000
                  Pamlico Sound               0          0         0          0          0
                  Total Coastal               0          0         0          0          0
                  Total                       0      6000     14000      27520      33840

                                          1949     1954E       1959      1964E       1969

                  Chowan River                0       960      1920       1920       1920
                  Roanoke River         21120      40000      62720      70000      76160
                  Albemarle Sound             0      2000      4480       5000       5760
                  Tar-Pamlico R.          3840     12000      18560      23000      27520
                  Neuse River           15360      30000      58880      70000      85120
                  Pamlico sound               0          0         0          0          0
                  Total Coastal               0      2000      4480       5000       5760
                  Total                 40320      84960      146560     169920     196480

                                        1974E      1978E       1982       1987

                  Chowan River            3100       4400      5760       7000
                  Roanoke River         82000      89000      95360      100000
                  Albemarle Sound         5400       5200      5120       5000
                  Tar-Pamlico R.        30000      33000      36480      39000
                  Neuse River           95000      110000     126080     150000
                  Pamlico Sound               0          0         0          0
                  Total coastal           5400       5200      5120       5000
                  Total                 215500     241600     268800     301000

                     Appendices                                                                     151
                     Appendix 3.2g. Acres "Other Land", calculated by subtracting sum of harvested
                     cropland, pasture, other farmland, forested land and urban land from total land area

                                          1880       1890       1900       1910       1920

                     Chowan River       248189     245361    198499     167122     147289
                     Roanoke River      172914     206666    121394     166274     103361
                     Albemarle Soun     229281     237954    246709     246919     210741
                     Tar-Pamlico R.     513051     485735    500640     454492     434779
                     Neuse River        643890     571417    557250     536196     465787
                     Pamlico Sound       78985      80715     80831       73724      68668
                     Total            1886310    1827848    1705323    1644727     1430625
                     coastal            308266     318669    327540     320643     279409

                                          1925       1930       1935       1940        1945

                     Chowan River       161928     150947    196590     240336     233383
                     Roanoke River      149846     171997    258784     297452     290334
                     Albemarle Soun     200256     195557    196233     200206     184898
                     Tar-Pamlico R.     396653     403859    372433     378034     347382
                     Neuse River        460087     507336    475128     433548     421141
                     Pamlico Sound       68710       82615    77816       79577      78558
                     Total            1437481    1512311    1576984    1629153     1555697
                     coastal            268966     278172    274049     279783     263456

                                          1950       1954       1959       1964        1969

                     Chowan River       199445     229897    263276     271057     217959
                     Roanoke River      154995     223557    229375     244515     446606
                     Albemarle Soun     144860     115854     87482     146137     153627
                     Tar-Pamlico R.     236684     209155    181915     231585     258758
                     Neuse River        302418     289883    310915     390294     403120
                     Pamlico Sound       74287       70032    62951       96441       97678
                     Total            1112689    1138378    1135913    1380029     1577748
                     coastal            219147     185886    150433     242578     251305

                                          1974       1978       1982       1987

                     Chowan River       140560     239241    295407     479574
                     Roanoke River      516915     571626    645686    1239652
                     Albemarle Soun     153877     172516    215454     280180
                     Tar-Pamlico R.     279001     266857    337647     532188
                     Neuse River        406912     398604    470223     721907
                     Pamlico sound       96065     103186    108256     120014
                     Total            1593330    1752030    2072673    3373513
                     Coastal            249942     275702    323709     400194

                   152                                                                  Appendices
                   Appendix 3.3a. Acres of Cotton

                                          1880        1890       1900       1910      1920

                   Chowan River          88793        82613      53869      49240    78840
                   Roanoke River         70835        79539      55479      61555    65597
                   Albemarle sound       26617        28447      20792      32705    36445
                   Tar-Pamlico R.       177765     198983        125439     188211  173018
                   Neuse River          218561     258981        201940     250561  248026
                   Pamlico Sound          3398        3313       2682       7096      8029
                   Total Coastal         30015        31760      23475      39801    44474
                   Total                585970     651877        460202     589368  609954

                                          1925        1930       1935       1940      1945

                   Chowan River         131248     114726        67794      44336    47847
                   Roanoke River        109380        93829      58149      36765    37771
                   Albemarle Sound       47896        36180      17723      9772     13366
                   Tar-Pamlico R.       255884     209202        120769     78933    83691
                   Neuse River          318540     263494        155061     88517    99389
                   Pamlico Sound          5413        4925       2281       1925      2505
                   Total Coastal         53309        41105      20004      11697    15871
                   Total                868361     722355        421776     260248  284568

                                          1950        1954       1959       1964      1969

                   Chowan River          58204        37028      32360      43949    23589
                   Roanoke River         49128        33119      27138      39170    19172
                   Albemarle Sound        8633        5018       3523       2666         743
                   Tar-Pamlico R.       104717        65138      54174      62812    24843
                   Neuse River          117427        69780      57240      40509     6045
                   Pamlico Sound          1090         188         166         53          2
                   Total Coastal          9723        5206       3688       2719         746
                   Total                339198     210270        174601     189159   74395

                                          1974        1978       1982       1987

                   Chowan River          18717        4085       10861      16782
                   Roanoke River         16475        3586       8781       15192
                   Albemarle sound           561       145       2055       5010
                   Tar-Pamlico R.        21246        6847       16010      23540
                   Neuse River            2018         379         813      3243
                   Pamlico Sound               0          0          0          0
                   Total Coastal             561       145       2055       5010
                   Total                 59017        15041      38521      63767

                      Appendices                                                                      153
                      Appendix 3.3b. Acres of Corn

                                             1880       1890       1900        1910       1920

                      Chowan River         250538     223285      247696    227704     218000
                      Roanoke River        438406     405352      469645    439683     435434
                      Albemarle Sound      130990     123063      123291    106009     105400
                      Tar-Pamlico R.       227416     215942      251102    218008     210797
                      Neuse River          310732     320067      382387    342766     338137
                      Pamlico Sound         14765      12787      13630      14905      15727
                      Total Coastal        145755     135850      136921    120914     121126
                      Total                1372847    1300496    1487751    1349075    1323494

                                             1925       1930       1935        1940       1945

                      Chowan River         167531     168164      189603    206713     196529
                      Roanoke River        360268     369001      397501    406418     356745
                      Albemarle Sound       82458      63821      96254      99345      96222
                      Tar-Pamlico R.       174197     180371      243641    263587     238970
                      Neuse River          270262     284565      364595    375396     383849
                      Pamlico Sound         12832      13560      17364      17439      14095
                      Total Coastal         95290      77381      113618    116784     110317
                      Total                1067548    1079483    1308958    1368898    1286410

                                             1950       1954       1959        1964       1969

                      chowan River         187997     196799      163185    122244     122487
                      Roanoke River        306596     270905      220661    159497     110830
                      Albemarle Sound       87304      90849      98910      78459      71830
                      Tar-Pamlico R.       240621     244216      253064    161115     140425
                      Neuse River          407992     428207      448365    298669     274622
                      Pamlico Sound         10146      10953      49696        9166       9139
                      Total Coastal         97451     101802      148606     87625      80968
                      Total               1240657     1241929    1233881    829150     729333

                                             1974       1978       1982        1987

                      chowan River         170285     192011      163193    107545
                      Roanoke River        143423     156428      139871     93580
                      Albemarle Sound      109513     138304      136877    101746
                      Tar-Pamlico R.       198971     223166      187257    162888
                      Neuse River          321874     322969      294461    256582
                      Pamlico Sound         15845      16373      21956      15731
                      Total Coastal        125358     154677      158833    117477
                      Total                959911    1049251      943615    738071

                   154                                                                  Appendices
                   Appendix 3.3d. Acres of Hay

                                           1880      1890       1900        1910      1920

                   Chowan River            2833      13146      15560     35712      36812
                   Roanoke River           35658     67925      77205     98942     125720
                   Albemarle Sound         1195      2239       2959        5199     14069
                   Tar-Pamlico R.          1692      6046       9913      19061      27175
                   Neuse River             1803      9173       14818     32196      37473
                   Pamlico Sound             50        243        570       1922      2005
                   Total Coastal           1245      2482       3529        7121     16074
                   Total                   43232     98773      121026    193032    243253

                                           1925      1930       1935        1940      1945

                   Chowan River            42355   174382       180169    173971     39437
                   Roanoke River           131498  144099       191857    258985    264423
                   Albemarle Sound         15795     21764      31302     23926       7039
                   Tar-Pamlico R.          31118     48939      103188    104084     64779
                   Neuse River             36540     41341      108717    120655    124524
                   Pamlico Sound           1858      1285       4698        1829      1553
                   Total Coastal           17653     23049      36000     25755       8593
                   Total                   259163  431811       619931    683450    501756

                                           1950      1954       1959        1964      1969

                   Chowan River            44746     77269      62507     43164      20645
                   Roanoke River           276568  322427       251549    177750    136053
                   Albemarle Sound         2314      9800       3883        4166      1339
                   Tar-Pamlico R.          59615     81630      60094     33795      13534
                   Neuse River             88847     71991      41947     23911      15364
                   Pamlico Sound            614        521        335        254         335
                   Total Coastal           2928      10321      4218        4421      1674
                   Total                   472704  563638       420315    283040    187270

                                           1974      1978       1982        1987

                   Chowan River            20377     23008      25020     26951
                   Roanoke River           139586  157796       169578    176775
                   Albemarle Sound         1563        672         532      1158
                   Tar-Pamlico R.          12603     14954      15743     21013
                   Neuse River             16947     22813      23082     23218
                   Pamlico Sound             315       291         126        224
                   Total Coastal           1877        963         658      1382
                   Total                   191391  219534       234081    249339

                      Appendices                                                                      155
                      Appendix Me. Acres of Oats

                                             1880       1890        1900      1910        1920

                      chowan River           50531     41540      16339       10074       2890
                      Roanoke River         211057     175138     110177      57683     25164
                      Albemarle Sound        6741       9866        3047      2568        1075
                      Tar-Pamlico R.         34304     47167      18338       10882       4061
                      Neuse River            37656     53483      26171       18823       7683
                      Pamlico Sound           891       1692        975       1040          849
                      Total Coastal          7631      11558        4022      3608        1925
                      Total                 341180     328887     175048     101071     41721

                                             1925       1930        1935      1940        1945

                      chowan River            692        972        927       1051        2741
                      Roanoke River          7004       5936        6253      7785        9634
                      Albemarle Sound         287        261        333        617        1845
                      Tar-Pamlico R.          489        621        1375      3903        9228
                      Neuse River             905        999        1088      2750        8314
                      Pamlico Sound           586        512        326        498        1705
                      Total Coastal           873        773        659       1115        3550
                      Total                  9963       9301      10302       16604     33467

                                             1950       1954        1959      1964        1969

                      chowan River           4387      16739        7491      2992        2640
                      Roanoke River          14892     27036      24038       11205       9715
                      Albemarle sound        1433       2269        2260      4219        4951
                      Tar-Pamlico R.         8873      17977      15659       7068        5974
                      Neuse River            11921     24547      21480       10790       9673
                      Pamlico Sound          1592       1508        806        494         917
                      Total Coastal          3025       3777        3066      4712        5868
                      Total                  43096     90075      71733       36767     33870

                                             1974       1978        1982      1987

                      Chowan River           1176       1168        1016       141
                      Roanoke River          6334       8582        4931      2745
                      Albemarle Sound        1874       1494        820       1481
                      Tar-Pamlico R.         3658       4452        6263      5603
                      Neuse River            5270      10582        7812      9408
                      Pamlico Sound           161          98       221          52
                      Total Coastal          2035       1591        1042      1533
                      Total                  18474     26376      21063       19430

                    156                                                                  Appendices
                    Appendix 3.3f. Acres of Peanuts

                                           1880       1890       1900       1910       1920

                    Chowan River                     43593     107910     156465     139240
                    Roanoke River                     1833      26947      54044      45511
                    Albemarle Sound                   1393       6640      10173       8821
                    Tar-Pamlico R.                    2040      20352      46721      23425
                    Neuse River                       1035       3350       8448       1330
                    Pamlico Sound                        14         36         86          7
                    Total Coastal                     1407       6677      10259       8827
                    Total                            49908     165236     275936     218334

                                           1925       1930       1935       1940       1945

                    Chowan River         135647     166071     170454     168057     176011
                    Roanoke River         55275      61234      67678      68230      75478
                    Albemarle Sound       15412      19636      19696      19494      23358
                    Tar-Pamlico R.        31045      45324      53889      56417      69992
                    Neuse River            2371       7365       8119       6885      10096
                    Pamlico Sound             40         62        127         63         25
                    Total Coastal         15452      19699      19823      19557      23383
                    Total                239789     299693     319964     319145     354959

                                           1950       1954       1959       1964       1969

                    Chowan River         160008     119086     120134     121017     127649
                    Roanoke River         65477      48899      47984      50255      53498
                    Albemarle Sound       13807      10125      10057      10180       9806
                    Tar-Pamlico R.        56024      43081      42957      45031      42063
                    Neuse River            5547       4481       4514       4581       4620
                    Pamlico Sound              7          5          1          1          1
                    Total Coastal         13815      10129      10058      10181       9807
                    Total                300871     225676     225646     231065     237636

                                           1974       1978       1982       1987

                    Chowan River         129255     129644     123493     108993
                    Roanoke River         48493      50655      47186      46577
                    Albemarle Sound        9378       9523       8610       8817
                    Tar-Pamlico R.        40863      42655      37836      37615
                    Neuse River            3826       4363       3794       3265
                    Pamlico Sound              0          0          0          0
                    Total Coastal          9378       9523       8610       8817
                    Total                231816     236840     220919     205267

                      Appendices                                                                       157
                      Appendix 3.3c. Acres of Corn for Silage

                                             1880       1890       1900        1910      1920

                      Chowan River
                      Roanoke River
                      Albemarle Sound
                      Tar-Pamlico R.
                      Neuse River
                      Pamlico sound
                      Total Coastal
                      Total

                                             1925        1930       1935       1940       1945

                      Chowan River             846       1375                  1134
                      Roanoke River          3727        4252                  3849
                      Albemarle sound            78       113                   212
                      Tar-Pamlico R.           313        554                   494
                      Neuse River              763       1524                  1557
                      Pamlico sound               0          0                     1
                      Total Coastal              78       114                   213
                      Total                  5728        7819                  7246

                                             1950        1954       1959       1964       1969

                      Chowan River           1619        4037       2992       5317       9503
                      Roanoke River          5462       11634      14497       29016     47205
                      Albemarle sound          335        249        359        763         821
                      Tar-Pamlico R.           746       2264       3130       3962       5999
                      Neuse River            1252        3911       4270       6951      10717
                      Pamlico Sound               1         27       239        241         445
                      Total Coastal            336        276        597       1004       1266
                      Total                  9416       22121      25486       46250     74689

                                             1974        1978       1982       1987

                      Chowan River           7397        6812       5759       5499
                      Roanoke River          39163      46626      40682       38316
                      Albemarle sound          908        298       1252        440
                      Tar-Pamlico R.         5449        6051       9833       5020
                      Neuse River            7822       10292       9743       6200
                      Pamlico Sound            538        341        427        161
                      Total Coastal          1446         639       1679        600
                      Total                  61277      70419      67695      55636

                    158                                                                  Appendices
                    Appendix 3.3g. Acres of Soybeans

                                           1880       1890       1900       1910       1920

                    Chowan River                                                       2949
                    Roanoke River                                                      1397
                    Albemarle Sound                                                   26374
                    Tar-Pamlico R.                                                     5339
                    Neuse River                                                        5120
                    Pamlico Sound                                                      3169
                    Total Coastal                                                     29544
                    Total                                                             44349

                                           1925       1930       1935       1940       1945

                    Chowan River                      8933      12513      18790      90183
                    Roanoke River                    14777      19338      26125      27507
                    Albemarle Sound                  42193      57143      65478      78317
                    Tar-Pamlico R.                   11168      29198      57222      61972
                    Neuse River                      14941      39769      71296     109879
                    Pamlico Sound                     6310       6696       7726       8101
                    Total Coastal                    48503      63840      73205      86418
                    Total                            98322     164657     246637     375958

                                           1950       1954       1959       1964       1969

                    Chowan River          13709      31156      66400      69531      76568
                    Roanoke River          6473      12498      26025      31957      49190
                    Albemarle sound       73605      85081      84354     104840     118302
                    Tar-Pamlico R.        41547      56355      81861     111900     121313
                    Neuse River           23013      26223      52555     114592     109261
                    Pamlico Sound         10451      12262      14732      18020      18601
                    Total Coastal         84056      97343      99086     122860     136903
                    Total                168797     223575     325928     450840     493234

                                           1974       1978       1982       1987

                    Chowan River         123513     136243     174778     167038
                    Roanoke River         82613     100538     127257     108167
                    Albemarle Sound      136261     157918     182765     138418
                    Tar-Pamlico R.       163577     208060     238801     180141
                    Neuse River          161536     252510     297729     228632
                    Pamlico Sound         20014      24329      30638      24009
                    Total Coastal        156275     182247     213403     162427
                    Total                687514     879598     1051967    846405

                     Appendices                                                                      159
                     Appendix 3.3h. Acres of Tobacco

                                             1880       1890       1900       1910       1920

                     Chowan River           11165      10042      18886      18399      32064
                     Roanoke River         108719     106789     156046     170347     216137
                     Albemarle Sound             5          0         32         19       388
                     Tar-Pamlico R.          5280      12343      47566      41952      98919
                     Neuse River             5721      11570      53540      67735     145568
                     Pamlico Sound               7          0         24          9       239
                     Total Coastal              13          0         56         27       627
                     Total                 130897     140744     276094     298460     493315

                                             1925       1930       1935       1940       1945

                     Chowan River           28068      31943      23787      37470      29090
                     Roanoke River         186729     216422     140627     196871     155236
                     Albemarle Sound          366       1429       5683       1143       1070
                     Tar-Pamlico R.         79407     141815      83896     136672     112652
                     Neuse River           128633     220503     127651     229675     189140
                     Pamlico Sound            233        451      12942        798        586
                     Total Coastal            600       1880      18624       1941       1656
                     Total                 423437     612563     394586     602630     487774

                                             1950       1954       1959       1964       1969

                     Chowan River           27470      30982      23479      19120      16168
                     Roanoke River         146410     160193     109731      98666      86564
                     Albemarle sound         1096       5791        842        772        634
                     Tar-Pamlico R.        103466     115046      77909      69810      63185
                     Neuse River           171673     190239     126790     114722      98907
                     Pamlico Sound            580        764        466        423        330
                     Total Coastal           1676       6555       1307       1194        964
                     Total                 450695     503015     339215     303513     265788

                                             1974       1978       1982       1987

                     Chowan River           17403      16973      14782       9613
                     Roanoke River          86936      92758      73742      47323
                     Albemarle Sound          469        509        567        344
                     Tar-Pamlico R.         62357      67683      55613      36753
                     Neuse River           102543     115434      97329      63606
                     Pamlico Sound            355        486        281        214
                     Total Coastal            824        995        849        558
                     Total                 270062     293844     242316     157853

                   160                                                                  Appendices
                   Appendix     3.3i, Acres of Wheat

                                          1880        1890       1900       1910       1920

                   chowan River          24441      16910      17730      11775      18408
                   Roanoke River        180601     174947     201298     169663     199870
                   Albemarle Sound        8801         669        159         39        318
                   Tar-Pamlico R.        26525      17777      12683        6706       8521
                   Neuse River           54149      46786      33055      15787      23387
                   Pamlico Sound            717         49         66         31        120
                   Total Coastal          9519         717        225         70        438
                   Total                295235     257139     264991     204001     250625

                                          1925        1930       1935       1940       1945

                   Chowan River          11540      12778      17797      12062      18395
                   Roanoke River        117466     141902     147326     104118     103720
                   Albemarle Sound          124          20         81        77        921
                   Tar-Pamlico R.         2238        3467     12806        8382     18452
                   Neuse River            7596        9605     17459      12417      35555
                   Pamlico Sound              13          0          4          1       159
                   Total Coastal            137          20         86        78       1081
                   Total                138977     167773     195473     137057     177202

                                          1950        1954       1959       1964       1969

                   Chowan River          13334      14334      21462      12826      12805
                   Roanoke River         89233      80048     106233      63502      38854
                   Albemarle Sound          125       1272       8754     19569      19253
                   Tar-Pamlico R.         8434      13068      28698      17984      18589
                   Neuse River           16818      21010      43602      33247      22985
                   Pamlico Sound              66        186        899      2338       1739
                   Total Coastal            190       1458       9653     21907      20992
                   Total                128009     129918     209648     149466     114225

                                          1974        1978       1982       1987

                   Chowan River          28469      10058      64870      31886
                   Roanoke River         61646      29983      84923      50776
                   Albemarle Sound       26694      19426      70587      49483
                   Tar-Pamlico R.        28048      14890      91088      65576
                   Neuse River           35863      18566      99534      78998
                   Pamlico Sound          3673        1656       9425       7765
                   Total Coastal         30367      21081      80012      57248
                   Total                184393      94578     420426     284483

                     Appendices                                                                      161
                     Appendix 3.4a. Tons of Nitrogen Sold as Fertilizer

                                             1880       1890       1900       1910       1920

                     Chowan River             164        440       1043       2378       3907
                     Roanoke River            247        664       1573       3587       5894
                     Albemarle Sound            51       138        327        747       1227
                     Tar-Pamlico R.           211        568       1346       3069       5044
                     Neuse River              316        850       2013       4591       7545
                     Pamlico Sound               5         13         30         68        112
                     Total Coastal              56       151        357        815       1338
                     Total                   1046       2818       6671      15214      25000

                                             1925       1930       1935       1940       1945

                     Chowan River            6663       4575       3417       3759       5230
                     Roanoke River           9503       8064       6146       6362       9110
                     Albemarle Sound         1785       1487        994       1491       2037
                     Tar-Pamlico R.          8275       7143       5038       4910       7015
                     Neuse River           11837      10248        7567       7229      10575
                     Pamlico sound            197        171        225        205         208
                     Total Coastal           1982       1658       1218       1696       2245
                     Total                 40185      33618      25322       25895      36120

                                             1950       1954       1959       1964       1969

                     Chowan River            6016       9076       8390      17134      14248
                     Roanoke River         10822      14613      14104       30498      25881
                     Albemarle Sound         2632       3035       3095       7243       8613
                     Tar-Pamlico R.          8638     10997      10898       24648      19373
                     Neuse River           13765      16446      16370       36624      33921
                     Pamlico Sound            252        369        377        718         846
                     Total Coastal           2883       3403       3473       7961       9459
                     Total                 44075      56490      55194      118829     104851

                                             1974       1978       1982       1987

                     Chowan River          18773      19142      17035       11762
                     Roanoke River         26999      28488      25801       21223
                     Albemarle Sound       15085      17645      17440       14338
                     Tar-Pamlico R.        28382      29976      25055       21612
                     Neuse River           41668      44641      39992       32044
                     Pamlico sound           1186       1352       1792       1629
                     Total Coastal         16271      18996      19232       15967
                     Total                 134068     143222     129097     104595

                   162                                                                  Appendices
                   Appendix 3.4b. Tons of Phosphorus Sold as Fertilizer

                                           1880       1890       1900       1910       1920

                   Chowan River             432        930       2293       5228       6639
                   Roanoke River            601       1294       3192       7280       9245
                   Albemarle Sound            81       175        432        985       1251
                   Tar-Pamlico R.           334        720       1776       4049       5142
                   Neuse River              500       1077       2656       6058       7692
                   Pamlico Sound               7         16        39          90        114
                   Total Coastal              89       191        471       1075       1365
                   Total                   2093       4508     11119      25357       32199

                                           1925       1930       1935       1940       1945

                   Chowan River            6807       4673       4472       4964       6524
                   Roanoke River           8961       7604       7424       7756      10490
                   Albemarle Sound         1094        912        780       1181       1525
                   Tar-Pamlico R.          5073       4379       3956       3891       5250
                   Neuse River             7256       6282       5942       5728       7915
                   Pamlico sound            121        105        177        162         156
                   Total Coastal           1215       1017        957       1344       1680
                   Total                 31237      25885      24686      25623       33804

                                           1950       1954       1959       1964       1969

                   Chowan River            6970     10442        9505       9480       7858
                   Roanoke River         11574      14242      13863      14705       13369
                   Albemarle Sound         1830       1816       1852       2123       2557
                   Tar-Pamlico R.          6005       6580       6521       7225       5752
                   Neuse River             9569       9840       9795     10736       10071
                   Pamlico Sound            175        221        226        211         251
                   Total Coastal           2005       2036       2078       2334       2808
                   Total                 38073      45095      43721      46443       41827

                                           1974       1978       1982       1987

                   Chowan River            6208       5921       5150       3486
                   Roanoke River           9583       9309       7577       6016
                   Albemarle Sound         4503       4630       4135       3194
                   Tar-Pamlico R.          8473       7866       5941       4814
                   Neuse River           12440      11714        9482       7138
                   Pamlico Sound            354        355        425        363
                   Total Coastal           4858       4985       4560       3557
                   Total                 43535      41773      34691      26998

                     AppendIces                                                                      163
                     Appendix 3.5a. Bales of Cotton

                                            1880        1890       1900       1910       1920

                     Chowan River          36767       17971      24443      23821      44543
                     Roanoke River         27184       16805      25959      30617      37445
                     Albemarle sound        9611        8063      10229      13407      22855
                     Tar-Pamlico R.        81565       50841      65111      98006     134161
                     Neuse River          104197       80523    100556      138952     178777
                     Pamlico Sound          1372         927         711      4175       5699
                     Total Coastal         10983        8991      10939      17582      28554
                     Total                260696     175131     227008      308979     423480

                                            1925        1930       1935       1940       1945

                     Chowan River          62331       63383      60825      30970      50064
                     Roanoke River         51462       49041      40055      15141      38501
                     Albemarle Sound       21117       11432      13047       3860      12446
                     Tar-Pamlico R.       136751       88898      82523      30050      79109
                     Neuse River          157801     101745       97313      38709      96914
                     Pamlico sound          2047        1910       1650         956      1783
                     Total Coastal         23164       13342      14697       4816      14229
                     Total                431509     316410     295412      119687     278818

                                            1950        1954       1959       1964       1969

                     Chowan River          33778       27508      28154      46517      15124
                     Roanoke River         32947       26910      23232      41056      13013
                     Albemarle sound        4703        3356       3398       2852         498
                     Tar-Pamlico R.        73595       50830      44815      63826      16269
                     Neuse River           84040       60573      47930      35551       3744
                     Pamlico Sound            311        167         145         51          3
                     Total Coastal          5014        3523       3543       2904         501
                     Total                229374     169343     147674      189854      48651

                                            1974        1978       1982       1987

                     Chowan River          17378        4908      14419      18017
                     Roanoke River         14924        4351      10608      15148
                     Albemarle Sound          578        168       2540       5214
                     Tar-Pamlico R.        20060        8293      17559      21897
                     Neuse River            1485         264        891       2965
                     Pamlico Sound              0           0          0          0
                     Total coastal            578        168       2540       5214
                     Total                 54424       17985      46017      63241

                   164                                                                  Appendices
                   Appendix 3.5b. Bushels of Corn

                                          1880       1890       1900       1910        1920

                   Chowan River        2580321    1783225    3395444    3029246    3990502
                   Roanoke River       6390943    5835343    8012306    7472801    7608621
                   Albemarle Sound     1652943    1310229    1618098    1087012    1682459
                   Tar-Pamlico R.      2374348    1798219    3051659    2858427    3932986
                   Neuse River         3208132    2846654    4335728    5076657    6465703
                   Pamlico sound         181492     183185     153446     308657     361435
                   Total Coastal       1834435    1493414    1771543    1395669    2043894
                   Total              16388179   13756855   20566681   19832800   24041707

                                          1925       1930       1935       1940        1945

                   Chowan River        2704572    3372395    3435016    4376747    4513973
                   Roanoke River       6613568    7331185    6806592    7816335    8130134
                   Albemarle Sound     1344970    1308184    2008679    2494120    2401026
                   Tar-Pamlico R.      2698231    3420667    4433788    5611212    5099416
                   Neuse River         4341535    5559168    6597272    8809941    8084821
                   Pamlico Sound         232955     275169     286255     405263     263539
                   Total Coastal       1577925    1583353    2294934    2899383    2664564
                   Total              17935831   21266768   23567602   29513618   28492908

                                          1950       1954       1959       1964        1969

                   Chowan River        6494775    5738784    7201377    6818532    9302938
                   Roanoke River       9233717    6868661    8226236   10379137    6443124
                   Albemarle Sound     2587068    3894377    6213976    5801976    6540886
                   Tar-Pamlico R.      7644613    6476970   11018351    9463849   10394339
                   Neuse River        12148043    8885929   17251153   19536249   19426012
                   Pamlico Sound         245768     443082     628593     780275     865986
                   Total Coastal       2832835    4337460    6842569    6582251    7406871
                   Total              38353983   32307804   50539686   52780018   52973285

                                          1974       1978       1982       1987

                   chowan River       13611823   15785668   16169257    5953410
                   Roanoke River       9492475   11544728   12593749    4748006
                   Albemarle sound    10990675   13156736   15444793    7250844
                   Tar-Pamlico R.     14698451   17080824   18367998    9900133
                   Neuse River        24502563   24347440   29374311   13487117
                   Pamlico sound       1489838    1484495    2362476    1319660
                   Total Coastal      12480513   14641231   17807269    8570504
                   Total              74785826   83399891   94312584   42659170

                     Appendices                                                                      165
                     Appendix 3.5c. Tons of Corn Silage

                                             1880       1890       1900       1910       1920

                     Chowan River
                     Roanoke River
                     Albemarle sound
                     Tar-Pamlico R.
                     Neuse River
                     Pamlico Sound
                     Total Coastal
                     Total

                                             1925       1930       1935       1940       1945

                     Chowan River            4075       9046                  8955
                     Roanoke River          28929      37497                 36250
                     Albemarle Sound           352      1053                  1656
                     Tar-Pamlico R.          1589       3387                  3601
                     Neuse River             4220       7519                 10073
                     Pamlico Sound               0          2                     4
                     Total Coastal             352      1056                  1661
                     Total                  39164      58505                 60540

                                             1950       1954       1959       1964       1969

                     Chowan River           14835      30458      37518      77414      90188
                     Roanoke River          55945      96680    135691      321846      542101
                     Albemarle Sound         3163       2629       3825       8318      12606
                     Tar-Pamlico R.          5790      15341      27109      40897      83793
                     Neuse River             8334      26652      40248      82221      145385
                     Pamlico Sound               5        215      2304       3684       6678
                     Total Coastal           3168       2844       6129      12002      19284
                     Total                  88071    171975     246695      534379      880750

                                             1974       1978       1982       1987

                     Chowan River           98726      91645      90982      45867
                     Roanoke River         519828    625478     588957      340074
                     Albemarle Sound        12570       4808      21270       5821
                     Tar-Pamlico R.         69044      84118    147682       64657
                     Neuse River           122850    126897     152093       63289
                     Pamlico sound           6910       4736       6829       1686
                     Total Coastal          19480       9544      28099       7507
                     Total                 829928    937683     1007813     521393

                   166                                                                  Appendices
                   Appendix 3.5d. Tons of Hay

                                          1880       1890       1900       1910       1920

                   Chowan River                     12159      17826      30547      71328
                   Roanoke River                    56644      74909     100828     267320
                   Albemarle Sound                   2490       3623       5841      16934
                   Tar-Pamlico R.                    6992      10466      17859      43976
                   Neuse River                      11650      14328      29311      49570
                   Pamlico Sound                       237       589       1495       1810
                   Total Coastal                     2728       4212       7336      18743
                   Total                            90172     121742     185881     450937

                                          1925       1930       1935       1940       1945

                   Chowan River          29560      86940      93913     122374      66452
                   Roanoke River        121940     136268     165126     259755     294935
                   Albemarle Sound       14673      17120      23567      20771      18212
                   Tar-Pamlico R.        20900      36523      93189      93189     105376
                   Neuse River           30521      44008      98366     131238     126279
                   Pamlico Sound          1323       1358       3530       2039       1666
                   Total Coastal         15995      18478      27097      22810      19878
                   Total                218917     322217     477690     629366     612920

                                          1950       1954       1959       1964       1969

                   Chowan River          53629      63377      56810      47990      31850
                   Roanoke River        331596     301569     310592     214602     210094
                   Albemarle sound        2733       7707       3599       4405       2187
                   Tar-Pamlico R.        60710      71853      57547      27453      19347
                   Neuse River           93879      66066      45361      30035      26618
                   Pamlico Sound            666        648       528         460        748
                   Total Coastal          3399       8354       4126       4865       2934
                   Total                543214     511219     474435     324946     290844

                                          1974       1978       1982       1987

                   Chowan River          32328      34199      43668      46380
                   Roanoke River        225393     242063     271379     288225
                   Albemarle sound        2642       1344        719       1824
                   Tar-Pamlico R.        18052      25816      24680      35723
                   Neuse River           30047      44757      42492      42408
                   Pamlico Sound            685        988       331         395
                   Total Coastal          3327       2332       1050       2219
                   Total                309148     349167     383269     414954

                       Appendices                                                                          167
                       Appendix 3.59. Bushels of Oats

                                               1880        1890        1900        1910        1920

                       Chowan River          386707      341517     168181      136679       35084
                       Roanoke River         1886163    1722809    1123882      678405      301943
                       Albemarle Sound        67624       90663       35006      34214       21984
                       Tar-Pamlico R.        305308      381034     191441      150210       70350
                       Neuse River           298664      389653     243286      268022      111296.
                       Pamlico Sound          11966       24361       20204      22626       24813
                       Total Coastal          79590      115024       55209      56839       46797
                       Total                 2956432    2950038    1781999      1290156     565470

                                               1925        1930        1935        1940        1945

                       Chowan River           11755       17703       12581      23608       65555
                       Roanoke River         111841       82064     107769      158210      239399
                       Albemarle Sound         8714        7097        5703      14107       57463
                       Tar-Pamlico R.         13085       14935       31859     113601      281787
                       Neuse River            13274       22805       23259     120010      240640
                       Pamlico Sound          19932       15177        7677      52219       49859
                       Total Coastal          28645       22275       13379      66327      107322
                       Total                 178600      159782     188846      481756      934704

                                               1950        1954        1959        1964        1969

                       Chowan River          131267      310629     279104      127631      151914
                       Roanoke River         409194      948772     831315      827771      456825
                       Albemarle Sound        35936       88759       91170     275456      512172
                       Tar-Pamlico R.        242227      692799     646177      344859      359026
                       Neuse River           355281     1040658     878348      555153      572605
                       Pamlico Sound          38041       55422       30892      25327       64176
                       Total Coastal          73977      144181     122062      300783      576348
                       Total                 1211947    3137038    2757007      2156197    2116718

                                               1974        1978        1982        1987

                       chowan River           63068       55811       47604      15388
                       Roanoke River         326768      349033     248465      204652
                       Albemarle Sound       128250      104960       61917     108318
                       Tar-Pamlico R.        133162      248459     430836      338685
                       Neuse River           323151      666404     467676      539835
                       Pamlico sound          11598        7926       19304        2918
                       Total Coastal         139848      112885       81221     111236
                       Total                 985997     1432592    1275801      1209796

                   168                                                                  Appendices
                   Apendix 3.5f. Pounds of Peanuts

                                          1880       1890       1900       1910       1920

                   Chowan River                    868127    3435236    4574972    6289441
                   Roanoke River                    54276    1016758    1746418    1934532
                   Albemarle Sound                  44089     283921     368065     502844
                   Tar-Pamlico R.                   54415     774099    1309557     919211
                   Neuse River                      22242     116395     252704       45432
                   Pamlico Sound                       346        704      2159         189
                   Total Coastal                    44436     284625     370224     503033
                   Total                          1043496    5627113    8253875    9691649

                                          1925       1930       1935       1940       1945

                   Chowan River        4852267    7857887    8376692  203529487 209273601
                   Roanoke River       2222494    2907866    3541864   79771795  94679528
                   Albemarle Sound       637763    852723    1078052   24067774  30077984
                   Tar-Pamlico R.      1090946    2058876    2627873   63326752  79864486
                   Neuse River            57752    195316     200009    4477110  10743407
                   Pamlico Sound            318        868      2451       3481       16196
                   Total Coastal         638081    853591    1080504   24071255  30094179
                   Total               8861541   13873536   15826942  375176399 424655202

                                          1950       1954       1959       1964       1969

                   Chowan River      207193638  160840580  204276530  237366038 282612868
                   Roanoke River      69206953   67487920   72818431  101851750 109207568
                   Albemarle Sound 15156266      14887880   15074636   22544474  23070871
                   Tar-Pamlico R.     53779524   51555148   61993240   88275842  79416764
                   Neuse River         4500102    4382160    5781551    7612521    8283414
                   Pamlico sound          2451       5188         462        348      1139
                   Total coastal      15158717   14893068   15075098   22544821  23072011
                   Total             349838934  299158876  359944850  457650973 502592624

                                          1974       1978       1982       1987

                   Chowan River      328300754  382115025  341206623  295386590
                   Roanoke River     111797996  135771715  127294528  124277990
                   Albemarle Sound    22639236   25969901   25345996   27115030
                   Tar-Pamlico R.     89562118  146562587   98692782   92197940
                   Neuse River         6998270   35740533    8806143    7797900
                   Pamlico sound            216          0          0          0
                   Total Coastal      22639452   25969901   25345996   27115030
                   Total             659298589  726159761  601346070  546775450

                      Appendices                                                                      169
                      Appendix 3.5g. Bushels of Soybeans

                                              1880       1890       1900       1910       1920

                      Chowan River                                                       45548
                      Roanoke River                                                       9584
                      Albemarle Sound                                                   289658
                      Tar-Pamlico R.                                                     60596
                      Neuse River                                                        46004
                      Pamlico Sound                                                      42957
                      Total Coastal                                                     332615
                      Total                                                             494347

                                              1925       1930       1935       1940       1945

                      chowan River                       34323      46794      52104    116156
                      Roanoke River                      29069      33684      47453     42204
                      Albemarle Sound                  464078     537930     704247     731619
                      Tar-Pamlico R.                   104572     170183     361723     283479
                      Neuse River                      163651     167586     250994     192794
                      Pamlico Sound                      93359      53649      58735     83836
                      Total Coastal                    557437     591579     762982     815455
                      Total                            889052    1009827    1475255    1450089

                                              1950       1954       1959       1964       1969

                      Chowan River          236466     465038    1487899    1518075    2045949
                      Roanoke River         112219     275584     602187     704143    1178296
                      Albemarle Sound     1316943     1693153    1866033    2368258    3475810
                      Tar-Pamlico R.        666069    1022885    1866714    2617079    3062273
                      Neuse River           368139     375981    1089787    2778967    2760935
                      Pamlico Sound         139682     230326     351806     447476     536108
                      Total Coastal       1456625     1923479    2217839    2815733    4011918
                      Total               2839518     4062966    7264427    10433998   13059371

                                              1974       1978       1982       1987

                      chowan River        2929171     3512261    4828998    3557430
                      Roanoke River       1723080     2187226    2924666    2196480
                      Albemarle Sound     3817049     4533536    5479864    4025264
                      Tar-Pamlico R.      3540330     4791327    6084392    4482856
                      Neuse River         4245568     5236890    7366296    5374026
                      Pamlico Sound         497502     702853     935811     719397
                      Total Coastal       4314551     5236389    6415675    4744661
                      Total               16752701   20964094   27620026   20355453

                  170                                                                  AppendIces
                  Appendix 3.5h. Pounds of Tobacco

                                         1880       1890       1900       1910        1920

                  Chowan River        6269098    4220492   13699551   15876712   16265270
                  Roanoke River      56073138   42368301   91989652   86590815   93269843
                  Albemarle Sound        1212           0      18840      10635    238419
                  Tar-Pamlico R.      2757909    4760453   31558725   26181703   64068964
                  Neuse River         2892930    4103194   38346601   45289260   98497641
                  Pamlico Sound            937          0      17187      7991     189562
                  Total Coastal          2149           0      36027      18626    427981
                  Total              67995224   55452441  175630555  173957115  272529699

                                         1925       1930       1935       1940        1945

                  Chowan River       18424320   22331862   15855802   32123338   31517197
                  Roanoke River     149172059  135730521  100850413  167347622  159318828
                  Albemarle sound      326747     583447     515514    4923557    1048656
                  Tar-Pamlico R.     46043627   88175177   77013284  126920402  118536048
                  Neuse River        78861495  145151157  129685318  217519328  199018836
                  Pamlico sound        408669     234638     169135      681150    489941
                  Total Coastal        735416     818085     684649    5604707    1538597
                  Total             293236916  392206802  324089466  549515398  509929506

                                         1950       1954       1959       1964        1969

                  Chowan River       28969457   30041395   29734396   38666393   28165711
                  Roanoke River     149750682  174097894  140131708  202389028  152428157
                 .Albemarle Sound      836629    1710682    1793296    2562191    1122894
                  Tar-Pamlico R.    117955288  138088449  110966851  154115035  113444082
                  Neuse River       179626088  234193810  183553067  260415723  182744698
                  Pamlico Sound        459520     905577    2329885    3223609     546659
                  Total Coastal       1296149    2616258    4123181    5785800    1669553
                  Total             477597644  579037806  468509202  661371979  478452200

                                         1974       1978       1982       1987

                  Chowan River       31000432   32375653   26119977   24507040
                  Roanoke River     158764930  176451829  143526408   94965940
                  Albemarle sound      874867    1474616    1212179      818740
                  Tar-Pamlico R.    104214173  118533466  115527339   76950630
                  Neuse River       213084360  243842750  204103936  136178610
                  Pamlico Sound        591018     914422     555941      439710
                  Total Coastal       1465886    2389038    1768121    1258450
                  Total             508529780  573592737  491045782  333860670

                      Appendices                                                                       171
                      Appendix 3.5i. Bushels of Wheat

                                              1880       1890        1900       1910       1920

                      Chowan River          213776     159017     171018      128393     156907
                      Roanoke River        1235672    1507691    1367172    1472155     2131825
                      Albemarle Sound        40203       3956          997       355       3511
                      Tar-Pamlico R.        169908     120911       68390       53916     94652
                      Neuse River           306268     304797     179663      133703     191829
                      Pamlico Sound           5779         436         453       258       1275
                      Total Coastal          45982       4392        1450        613       4785
                      Total                1971605    2096808    1787693    1788781     2579998

                                              1925       1930        1935       1940       1945

                      Chowan River          140283     258350     194871      158889     336152
                      Roanoke River        1320564    1400670    1333794    1214630     1681375
                      Albemarle sound         1913         294       1092        719      16616
                      Tar-Pamlico R.         21900      37910     156452      106429     312899
                      Neuse River            72842      94246     164333      147263     644666
                      Pamlico Sound             ill           0         26         12      2500
                      Total Coastal           2024         294       1118        731      19116
                      Total                1557614    1791470    1850568    1627942     2994209

                                              1950       1954        1959       1964       1969

                      Chowan River          236507     350810     263400      344314     629845
                      Roanoke River        1666350    1879971    1390338    1741241     1563666
                      Albemarle Sound         1402      30130        1402     664247     959675
                      Tar-Pamlico R.        115155     315693     115555      603972     848491
                      Neuse River           214187     514359     214437    1162102     1060861
                      Pamlico Sound             871      5492          871      77881     77890
                      Total Coastal           2273      35622        2273     742128    1037566
                      Total                2234472    3096455    1986003    4593758     5140428

                                              1974       1978        1982       1987

                      Chowan River         1055139     324018    1970039    1245035
                      Roanoke River        2161180     896969    2460805    2027765
                      Albemarle Sound      1033841     477510    2975475    2653952
                      Tar-Pamlico R.        998769     514940    3092312    2684475
                      Neuse River          1252918     602222    3258152    3156290
                      Pamlico Sound         130467      68359     417439      361765
                      Total Coastal        1164308     545869    3392914    3015717
                      Total                6632315    2884017    14174221   12129282

                  172                                                                  Appendices
                  Appendix 3.6. Crop Yields, calculated by dividing harvest by harvested acres

                                         1880       1890       1900       1910       1920

                  COTTON (lb/acre)        222        134        247        262        347
                  CORN (bu/acre)         11.9       10.6       13.8       14.7       18.2
                  HAY (tons dry/acre)               0.91       1.01       0.96       1.85
                  OATS (bu/acre)          8.7        9.0       10.2       12.8       13.6
                  PEANUTS (lb/acre)                  523        851        748       1110
                  SILAGE (tons green/acre)
                  SOYBEANS (bu/acre)                                                 11.1
                  TOBACCO (lb/acre        519        394        636        583        552
                  WHEAT (bu/acre)         6.7        8.2        6.7        8.8       10.3

                                         1925       1930       1935       1940       1945

                  COTTON (lb/acre)        248        219        350        230        490
                  CORN (bu/acre)         16.8       19.7       18.0       21.6       22.1
                  HAY (tons dry/ac       0.84       0.75       0.77       0.92       1.22
                  OATS (bu/acre)         17.9       17.2       18.3       29.0       27.9
                  PEANUTS (lb/acre        924       1157       1237       1176       1196
                  SILAGE (tons gre       6.84       7.48                  8.35
                  SOYBEANS (bu/acre)                 9.0        6.1        6.0        3.9
                  TOBACCO (lb/acre        693        640        821        912       1045
                  WHEAT (bu/acre)        11.2       10.7        9.5       11.9       16.9

                                         1950       1954       1959       1964       1969

                  COTTON (lb/acre)        338        403        423        502        327
                  CORN (bu/acre)         30.9       26.0       41.0       63.7       72.6
                  HAY (tons dry/ac       1.15       0.91       1.13       1.15       1.55
                  OATS (bu/acre)         28.1       34.8       38.4       58.6       62.5
                  PEANUTS (lb/acre       1163       1326       1595       1981       2115
                  SILAGE (tons gre       9.35       7.77       9.68       11.55      11.79
                  SOYBEANS (bu/acr       16.8       18.2       22.3       23.1       26.5
                  TOBACCO (lb/acre       1060       1151       1381       2179       1800
                  WHEAT (bu/acre)        17.5       23.8        9.5       30.7       45.0

                                         1974       1978       1982       1987

                  COTTON (lb/acre)        461        598        597        496
                  CORN (bu/acre)         77.9       79.5       99.9       57.8
                  HAY (tons dry/ac       1.62       1.59       1.64       1.66
                  OATS (bu/acre)         53.4       54.3       60.6       62.3
                  PEANUTS (lb/acre       2413       3066       2722       2664
                  SILAGE (tons gre      13.54      13.32      14.89       9.37
                  SOYBEANS (bu/acr       24.4       23.8       26.3       24.0
                  TOBACCO (lb/acre       1883       1952       2026       2115
                  WHEAT (bu/acre)        36.0       30.5       33.7       42.6

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                 174                                                                   Appendices
                 Appendix 3.7. Continued

                 Animal/Basin                               Year

                 TURKEYS       1959E     1964E      1969      1974     1978      1982      1987E

                 chowan         4241     12359         40        30      143        40        68
                 Roanoke       11245     10567      1153       592     1421       716      1217
                 Tar            4812     26547        149     1726   384445     210164    357279
                 Neuse         17850     21765     64491    123743   612472    1006477   1711011
                 Coastal       12724     17827          2        41         0         0         0
                 Total         50871     89065     65834    126132   998480    1217397   2069575

                 SHEEP          1880      1890      1900      1910     1920      1925

                 Chowan        22798     25089     19014    14766      7665      5154
                 Roanoke       67916     62638     56381    50636     19130     18024
                 Tar           21433     18769     14146      8721     4588      2942
                 Neuse         32793     25000     16497      8159     3165      2398
                 coastal       10967     12390     12057    15587     10398      5406
                 Total        155907    143886    118095    97870     44946     33924

                 SHEEP          1930      1935      1940      1945     1950      1954

                 Chowan         9446      6328      4114      4063     4011      5518
                 Roanoke       34171     18572     12896    10393     12732      9781
                 Tar            4108      3755      2561      3039     2570      2665
                 Neuse          2954      2306      1731      1868     1879      1899
                 coastal       11856      8128      6177      6596     6114      4861
                 Total         62534     39089     27479    25960     27306     24724

                 SHEEP          1959      1964      1969      1974     1978      1982      1987E

                 Chowan         5700      4218      3594      1759     2271      3107      3107
                 Roanoke       12075      7683      6467      5483     4716      4141      4141
                 Tar            2848      1440        640       325        66     149        149
                 Neuse          3077      1787      1613      1054        328     865        865
                 Coastal        3297      2701      1504        657       902     525        525
                 Total         26997     17829     13819      9277     8283      8786      8786

                 MULES          1880      1890      1900      1910     1920      1925

                 Chowan         5789      5674      7425      9905    26089     25321
                 Roanoke       15079     16212     17910    23645     42357     44583
                 Tar            8108      8768     10344    14462     26915     30100
                 Neuse         11385     13610     19212    25107     45625     46320
                 Coastal        2432      2362      2761      2998     6666      8412
                 Total         42793     46627     57652    76117    147654     154735

                       Appendices                                                                       175
                       Appendix 3.7. Continued

                       Animal/Basin                                Year

                       MULES          1930      1935      1940      1945      1950      1954

                       Chowan        27166     26612     28341     26372     23506     15614
                       Roanoke       52385     51350     57500     52596     52634     39347
                       Tar           37227     36208     38848     36516     40077     29871
                       Neuse         50469     50681     54213     52153     52364     35229
                       Coastal        9110      9689      8891      6793      3943      2050
                       Total         176356    174540    187793    174430    172523    122112

                       MULES         1959E     1964E      1969      1974      1978      1982      1987E

                       Chowan        10699      5784       869       236         86         9         9
                       Roanoke       27702     16057      4412      1324       639        134       134
                       Tar           20817     11763      2709       488       208         42        42
                       Neuse         24003     12777      1551       217       115          9         9
                       Coastal        1378        706        33         1         1         0         0
                       Total         84600     47087      9574      2266      1049        194       194

                       HORSES         1880      1890      1900      1910      1920      1925

                       Chowan        14268     14313     21887     22308     20566     14696
                       Roanoke       39600     41003     54279     58562     59183     47397
                       Tar           11230     10630     16385     16995     17293     11416
                       Neuse         15208     13222     16704     18966     19236     12975
                       Coastal        6144      6919      8285      8927      8671      7137
                       Total         86450     86087     117541    125757    124949    93620

                       HORSES         1930      1935      1940      1945      1950      1954

                       Chowan         9728      6094      5881      6539      7043      3820
                       Roanoke       35106     23388     23173     24847     25460     17595
                       Tar            7127      3960      3552      3889      4628      3507
                       Neuse          8016      4776      3801      4649      5895      4485
                       Coastal        4642      3546      2997      2721      2440      1222
                       Total         64620     41764     39404     42646     45466     30629

                       HORSES        1959E     1964E      1969      1974      1978      1982      1987E

                       Chowan         2751      1683       614      1434      1319      1555      1555
                       Roanoke       12603      7611      2619      5743      5407      6099      6099
                       Tar            2607      1707       806      1081      1213      1154      1154
                       Neuse          3364      2242      1121      2111      2459      2708      2708
                       Coastal          868       514      160       326       288        324       324
                       Total         22193     13757      5321     10694     10685     11841      11841

                                           068VLV       OLLLSE       OLZTSE       68609Z       9MOC        09T60Z            -[vqoL
                                           6E9TZ        ZTM          0688T        MET          09ZST       t6vzT          lvqgTaoo
                                           VTOT8        889ts        Z99LS        TOZZt        86s9s       SS9ZE             esneN
                                           69L69        6860v        9ZOEV        S680E        8LZ6E       TVZTZ               .77al
                                           S16LEZ       Z8T86T       6S6ZST       E086ET       6VLZST      86VVTT         G%ouleo-d
                                           ESSPL        OOL6V        EELSD,       09ZVE        TSS6E       ZLZ8Z           uvmoqo

                                           D,96T        OS6T         061          ot6T         SE61        OC6T            zrllLVD

                                           LVLLtZ       T968TE       OEME         E6S9TE       C98LTE      99SLSE            Tv-40I
                                           SUPT         OSZEZ        ZTOLZ        E9ELZ        ZZSOE       TLSTE.         -Ev4svoo
                                           8060V        V9ZTS        S668S        VSEVS        TSOSS       OSLvL             esnaN
                                           LZS8Z        SZELE        GLOP         666EV        OTZTV       698LS               aVI
                                           EEZ8ZT       OOE8ST       LZSPST       S80SET       LSLZET      t6ZLET         63[ouleo-d
                                           C98SE        8188v        TZSSS        Z6LSS        EMS         0809S           upmoqo

                                           SUT          OUT          0161         006T         06ST        088T            SUM

                              8L6VVL8T     L8S9EL9T     EV966TST     TtOSOVS      8E9E8SV      OOT06ZV     898TZLV           TV-401
                              TTELOVT      SZ999ZT      800868       t,6LEST      99DI09T      E6ZZCZ      Et6lZC         TV48VOD
                              OVEZVOV      ZEZ609E      Z866S8V      6TZE19E      0869T6T      E9ZL6VT     6VSVSVT           asneN
                              66EL6Z9      LL9ZZ9S      6OE9ETE      6SE6V8T      SZE868       TZP989      ZE6T9L              aVI
                              ZVSE09E      9TLLTZE      88EL8EE      SSTSS6T      89ZSSZT      t6E68ET     99SSZ9T        8:40uleO'd
                              L8OV6EE      PEVOEOE      9S6LT6Z      VSVEE8       019ZSC       OELV8V      888VSS          UL*Aoqo

                              HL86T        Z86T         8L6T         tL6T         696T         096T        6G6T          SNZXDIHO

                                           80VVVSV      ZSZELEV      OLLEVLS      8OLVE8E      Z8tT6ZS     TOME              TV401
                                           SS99LZ       TLZVLZ       69VOOV       9E610C       LE968t      8VSV6Z         T94svOO
                                           L89EOVT      8VETZZT      OT908ST      6SBEV6       SL89EZT     OVLZES            esnoN
                                           896tTL       OL86EL       V06SP6       8LTS19       LT9TO8      STOLVS              avL
                                           ZMtST        VTEVZST      L88ZTOZ      8VZ6StT      OT6SELT     LSTS6ET        95[OuvO-d
                                           9L966S       OStET9       006EO8       LSMS         MLZOT       6L98SS          uvmolqo

                                           tS6T         OS6T         MT           Ot6T         SE6T        OE6T          SNHXDIHO

                                           9S6T80       THEM         tSLETOE      60666ZZ      ZSSME       90Z691            [leqol
                                           9TELLE       99SZtE       OSLOSZ       18TOZZ       OTtStE      88T98T         TVISVOO
                                           8868tll      Z98EZOT      tZTSOL       08S99t       89SBES      99ETSE            asnem
                                           6MLL         OT8OL9       OZEL9t       8080SE       E86LZG      69t99Z              aVj
                                           tT686LT      T908tST      9896ZTT      689EL8       OtMT        TES609         8310uvo-d
                                           60EZ89       Z86LE9       MM           OS98SE       MM          EUM             uvmoqo

                                           SZ61         OZ61         OT6T         006T         0681        088T          SNZXDIHO

                                                                                                                  uTsvg/TlewTuY

                                                                                                 penulluo:D TC XIPUeddV
                        sgolpueddV                                                                                             9LI

                       Appendices                                                                      177
                       Appendix 3.7. Continued

                       Animal/Basin                               Year

                       CATTLE         1959     1964       1969      1974      1978     1982       1987

                       Chowan       60893     65341     61632     72546     56612     61250     76640
                       Roanoke     220866    229758    245456    313944    257871    303281     356357
                       Tar          52409     59887     51059     63681     46568     44567     53464
                       Neuse        64633     74388     70624     78839     70559     71233     70686
                       Coastal      16617     21240     18266     18783     11102      8325     11092
                       Total       415418    450613    447037    547792    442712    488656     568239

                       BROILERS     1880E     1890E     1900E     1910E     1920E     1925E

                       Chowan            0     6628     13255     19883     26511     29824
                       Roanoke           0    44999     89998    134998    179997    202496
                       Tar               0    48325     96650    144974    193299    217461
                       Neuse             0   119239    238477    357716    476954    536574
                       Coastal           0       232       463       695       926     1042
                       Total             0   219422    438843    658265    877687    987398

                       BROILERS     1930E     1935E     1940E     1945E     1950E     1954E

                       Chowan       33138     36452     39766     43080     46394     49045
                       Roanoke     224996    247496    269995    292495    314994    332994
                       Tar         241624    265786    289949    314111    338273    357603
                       Neuse       596193    655812    715432    775051    834670    882366
                       Coastal        1158     1273       1389      1505      1621     1713
                       Total       1097109   1206820  1316530   1426241  1535952   1623721

                       BROILERS     1959E     1964E       1969      1974      1974     1982     1987E

                       Chowan       52358     55672     58986    405246  2527410   2934388   3667985
                       Roanoke     355494    377993    400493    417427  2073553   2327470   2909337
                       Tar         381766    405928    430090    384696  1016318   2745128   3431410
                       Neuse       941985   1001604   1061223   1382506  1963347   3868738   4835922
                       Coastal        1829     1945       2061    78521    805238  1217358   1521697
                       Total      1733432   1843143   1952853   2668395  8385866   13093081  16366351

                  178                                                                    Appendices
                  Appendix 3.8. Annual nitrogen and phosphorus production (kg/year) by farm animals in the
                  Albemarle-Pamlico basin (1880-1987).

                  Nutrient/Basin                                 Year

                  NITROGEN        1880     1890      1900       1910      1920      1925

                  Chowan      6302054   6228903   7108818   7265782   7944822   6071906
                  Roanoke 14879492     14540027  15308356   16804815  18221559  15269092
                  Tar         6378220   5152520   5951295   6364301   6689057   5437007
                  Neuse       8852011   7437139   8092455   9057791   9733398   8145700
                  Coastal     3414161   3412757   3257875   3409853   3548036   2776870
                  Total      39825938  36771346  39718799   42902541  46136873  37700574

                  NITROGEN        1930     1935      1940       1945      1950      1954

                  Chowan      5540085   6437336   5155960   7508731   7658501   9177731
                  Roanoke    14073506  15969026  14980296   18230935  19444816  21159331'
                  Tar         4961073   6220553   5471179   6764858   7111455   7869522
                  Reuse       7242715   8962816   8043846   9806272   10090225  11276384
                  Coastal     2538904   2823247   2188981   2781296   2328735   2720594
                  Total      34356283  40412979  35840263   45092092  46633732  52203562

                  NITROGEN        1959     1964      1969       1974      1978      1982       1987

                  Chowan      7635426   6759978   6937741   7830546   8933804   9305266  10797441
                  Roanoke    19495283  18066928  18379813   22867892  21155313  24296835 27655762
                  Tar         7355499   6470679   5913871   7317532   8430494   11444897 12622176
                  Neuse      10226898   9067086   9893474   11685701  14013146  14601000 17430805
                  Coastal     2336814   2391444   2411419   2597154   3736367   3927342    4420564
                  Total      47049920  42756116  43536318   52298825  56269125  63575340 72926749

                  PHOSPHORUS      1880     1890      1900       1910      1920      1925

                  Chowan      1687262   1664229   1955084   2151673   2182893   1682618
                  Roanoke     3911243   3821383   4039684   4518506   4732874   4022536
                  Tar         1714675   1413390   1664164   1858726   '1873610  1553401
                  Neuse       2433313   2114302   2304296   2730436   2694946   2274100
                  Coastal       919114    926708    883378    969992  1012074     797343
                  Total      10623434   9818735  10643488   11442435  12418499  10092167

                  PHOSPHORUS      1930     1935      1940        1945     1950      1954

                  Chowan      1535994   1821381   1359372   2081977   2084575   2531156
                  Roanoke     3610253   4160759   3755277   4661720   4824546   5273977
                  Tar         1330043   1704605   1433532   1876072   1837216   2039961
                  Neuse       1970498   2452351   2153667   2692247   2611209   3000478
                  Coastal       727860    777248    579855    756408    658424     773717
                  Total       9194633  10770553   9428702   12089393  12570494  14031928

                       Appendices                                                                     179
                       Appendix 3.8. Continued

                       Nutrient/Basin                               Year

                       PHOSPHORUS     1959      1964      1969      1974      1978     1982      1987
                       Chowan     2117461   1852749   1983687  2200765   2582615   2653854   3024132
                       Roanoke    4896531   4521467   4624691  5715358   5428682   6191163   6953380
                       Tar        1964310   1731155   1666269  2089553   2588221   3561435   3877072
                       Neuse      2811170   2493617   2900085  3464430   4332556   4430399   5403074
                       Coastal      682272    679787    715638   772850  1188220   1251666   1387302
                       Total      12884382  11361302  11906450  14246302  16122645  18088517  20647094

                        86968T      LLTLZL     ESLZET      988809       LZLO8      ZSV60E    0          0                  -[P-401
                        0           0          0           0            0          0         0          0           TleTa4snpui
                        8696ST      LLTLZL     ESLZET      98880S       LZLO8      ZSV60E    0          0            IledToTunH
                                                                                                                     qV1101 d/V

                        MOOT        S698E      8T9L        IOZ6Z        T06E       SS6VT     0          0                  Ile-4ol
                        0           0          0           0            0          0         0          0           Tie-p-4snpui
                        V600T       9698C      819L        TOZ6Z        T06E       SGOT      0          0            TiedTOTunK
                                                                                                                         7visvoo

                        TS699       St99SZ     68tEV       60L99T       9699Z      9EEZOI    0          0                  IR-401
                        0           0          0           0            0          0         0          0           TPTiqsnpui
                        TS699       Gt99SZ     68tEt       60L99T       9699Z      9EEZOT    0          0            TedTOTunN
                                                                                                                           asnam

                        scost,      EE9ZLI     ZESOZ       90L8L        8TS8       TS9ZE     0          0                  'p-461
                        0           0          0           0            0          0         0          0           Tv-rzr-4snpui
                        SEOSV       EE9ZLT     ZESOZ       90M          8TS8       TG9ZE     0          0            TvdTDTunjj

                        Z9T6S       68L9ZZ     86TLS       6SZ6TZ       9EPOV      90OSSI    0          0                  -[Vqol
                        0           0          0           0            0          0         0          0           TieTaqsnpui
                        Z9T6S       68L9ZZ     86TLS       6SZ6TZ       9EVOt      90OSST    0          0            liedTOTunN
                                                                                                                         axoNvoll

                        9M          EIVZE      916E        ZIOST        SLIT       Vost      0          0                  TV-401
                        0           0          0           0            0          0         0          0           TRT:r-4snpuj
                        9ST78       ETtZE      9T6E        ZTOST        SLIT       Vost,     0          0            liedTOTunN
                                                                                                                           NVMOHD

                        A/f)Xcl     A/f)XK     A/!)Xcl     A/E)XN       A/!)Xcl    A/f)XN    A/!)Xcl    A/f)XN      9dAL/UTsieS
                           OT6T      OT6T         006T      006T        068T       068T       08ST        088T

                                                                                 a5utAas poluoijun ui juoA/uosjad/23j 1-1 puu
                   juoA/uosiad/N 231 9-t, sQwnssV '9861-0881 IsSuipuol aoinos juiod pjuwijs3 .6-1@ xipueddV
                       sao!pueddv                                                                                              091

                      Appendices                                                                    181
                      Appendix 3.9. Continued

                                    1920     1920     1930    1930     1940     1940    1950     1950
                      Basin/Type    NKG/Y    PKG/Y    NKG/Y   PKG/Y    NKG/Y    PKG/Y   NKG/Y    PKG/Y

                      CHOWAN
                      Municipal     40060    10450    58888   15362   110144    20907  143644    39646
                      Industrial         0        0   10000     2500   95000    25000  190000    50000
                      Total         40060    10450    68888   17862   205144    45907  333644    89646

                      ROANOKE
                      municipal    495599   129287  680745   177586   817491  213258  1017891   265537
                      Industrial         0        0 100000    35000   336000    64000  336000    64000
                      Total        495599   129287  780745   212586   1153491 277258  1353891   329537

                      TAR
                      Municipal    231679    60438  316969    82688   374602    97722  441187   115092
                      Industrial         0        0       0       0        0         0        0      0
                      Total        231679    60438  316969    82688   374602    97722  441187   115092

                      NEUSE
                      municipal    430714   112360  596170   155523   826471  215601  1066754   278284
                      Industrial         0        0       0       0        0         0     500       0
                      Total        430714   112360  596170   155523   826471  215601  1067254   278284

                      COASTAL
                      municipal     69860    18224    78375   20446    90781    23682   99921    26066
                      Industrial         0        0       0       0        0         0        0      0
                      Total         69860    18224    78375   20446    90781    23682   99921    26066

                      A?P TOTAL
                      Municipal 1267913     330760  1731147  451604  2219489  571171  2769397   724625
                      Industrial         0        0 110000    37500   431000    89600  526500   114600
                      Total        1267913  330760  1841147  489104  2650489  660771  3295897   839225

                  182                                                                  Appendices

                  Appendix 3.9. Continued

                                1960     1960     1970     1970     1980    1980     1986     1986
                  Basin/Type     NKG/Y   PKG/Y    NKG/Y    PKG/Y    NKG/Y   PKG/Y    NKG/Y    PKG/Y

                  CHOWAN
                  Municipal     174653   48969   151543    48363  144798    47731   148919    47895
                  Industrial 578000      88800   578000    88800  578000    88800   379000    88800
                  Total         752653  137769   729543   137163  722798   136531   527919   136695

                  ROANOKE
                  Municipal   1189291   312130   826474   294070  844729   304012   857012   310711
                  Industrial    336000   64000   336000    64600  336000    64600   336000    64600
                  Total       1525291   376130  1162474   358670  1180729  368612  1193012   375311

                  TAR
                  Municipal     401132  122638   382847   129738  427546   143756   490542   165046
                  Industrial          0        0  70000   400000    70000  535000    70000   391000
                  Total         401132  122638   452847   529738  497546   678756   560542   556046

                  NEUSE
                  Municipal   1138754   335908  1067645   358045  1214426  415634  1490523   510820
                  Industrial       1000     1200 256229    22277  256200    22277   256200    22277
                  Total       1139754   337108  1323874   380322  1470626  437911  1746723   533097

                  COASTAL
                  Municipal     107166   27956    73921    24141    79966   26155    87584    28610
                  industrial          0        0       0        0        0        0       0        0
                  Total         107166   27956    73921    24141    79966   26155    87584    28610

                  A/P TOTAL
                  Municipal   3010996   847602  2502429   854356  2711465  937289  3074580   1063082
                  Industrial 915000     154600  1240229   575677  1240200  710677  1041200   566677
                  Total       3925996   1002202 3742658   1430033 3951665  1647966 4115780   1629759

                       Appendices                                                                          183
                       Appendix 4. 1. Pamlico River estuary sampling dates, parameters sampled, and data
                       sources

                       Abbreviations:

                        ST            Surface water temperature (OC)
                        BT            Bottom water temperature (OC)
                        SS            Surface water salinity (ppt)
                        BS            Bottom water salinity (ppt)
                        SDO           Surface water dissolved oxygen (mg/liter)
                        BDO           Bottom water dissolved oxygen (mg/liter)
                        PH            Surface water pH
                        P04           Surface water orthophosphate phosphorus (uM)
                        TDP           Surface water total dissolved phosphorus (uM)
                        TP            Surface water total phosphorus (uM)
                        PP            Surface water particulate phosphorus (uM)
                        N03           Surface water nitrate nitrogen (uM)
                        NH4           Surface water ammonia nitrogen (uM)
                        TDN           Surface water total dissolved nitrogen (uM)
                        TN            Surface water total nitrogen (uM)
                        PN            Surface water particulate nitrogen (uM)
                        CHL           Surface water chlorophyll a (ugAiter)

                       Key to data source references (see REFERENCES for full citations):
                        1. Hobbie (1970b)
                        2. Hobbie (1970a)
                        3. Hobbie et al. (1972)
                        4. Hobbie (1974)
                        5. Stephenson et al. (1975)
                        6. ICMR (1976)
                        7. ICMR (1977)
                        8. ICMR (1978)
                        9. ICMR (1980)
                        10. ICMR (1981)
                        11. ICMR (1982)
                        12. ICMR (1983)
                        13. Stanley (1984b)
                        14. Stanley (1986a)
                        15. Stanley (1986b)
                        16. Stanley (1987)
                        17. Davis et al. (1978)
                        18. Kuenzler et al. (1979)
                        Note: The data from 23 October 1978 through 14 December 1978 are in none ofthe reports. I
                       have access to the data however. (D.W.S.)

                  184                                                             Appendices

                  Appendix 4. 1. Continued

                    Sample                Parameters Sampled and Data Sources
                    Date

                  MO DA YR  ST  BT SS BS SDO BDO PH P04 TDP TP PP M03 NH4 TDN TN PN CHL

                    3  967   2    2
                    322 67   2    2
                    323 67
                    411 67   2    2
                    5  967   2    2                 1    1  1
                    6  767   2    2
                    627 67   2    2
                    628 67                          1    1  1
                    713 67   2    2                 1    1  1
                    731 67   2    2                 1    1  1
                    823 67   2    2                 1    1  1
                    830 67   2    2                 1    1  1
                    .9 20 67 2    2                 1    1  1
                  10   367   2    2
                  10   467                          1    1  1
                  10 17 67   2    2                 1    1  1
                  10 30 67   2    2                 1    1  1
                  11 14 67   2    2                 1    1  1
                  11 28 67   2    2                 1    1  1
                  12 19 67   2    2                 1    1  1
                    1  868   2    2                 1    1  1
                    129 68   2    2                 1    1  1
                    213 68   2    2
                    214 68                          1    1  1
                    226 68   2    2                 1    1  1
                    629 68   2  2 2 2               1    1  1
                    716 68   2  2 2 2               1    1  1
                    8  668   2  2 2 2               1    1  1
                    823 68   2  2 2 2               1    1  1
                    9  668   2  2 2 2               1    1  1
                    930 68   2  2 2 2               1    1  1
                  10 11 68   2  2 2 2               1    1  1
                  11 21 68   2  2 2 2               1    1  1
                  12 13 68   2  2 2 2   2    2
                    1  669   2  2 2 2   2    2
                    2  669   2  2 2 2   2    2      1    1  1
                    226 69   2  2 2 2   2    2      1    1  1
                    4  169   2  2 2 2   2    2      1    1  1
                    415 69   2  2 2 2   2    2      1    1  1
                    5  269   2  2 2 2   1    2      1    1  1
                    6  369   2  2 2 2   2    2      1    1  1
                    619 69   2  2 2 2   2    2      1    1  1
                    7  469   2  2 2 2   2    2      1    1  1

                     Appendices                                                               185
                     Appendix 4. 1. Continued

                       Sample              Parameters Sampled and Data Sources
                       Date

                     MO DA YR  ST  BT SS BS SDO BDO PH P04 TDP TP PP N03 NH4 TDN TN PN CHL

                       8 6 69  3  3 3  3   3   3  3   1   1  1      3    3
                       821 69  3  3 3  3   3   3  3   1   1  1      3    3
                       9 3 69  3  3 3  3   3   3  3   1   1  1      3    3
                       917 69  3  3 3  3   3   3  3   1   1  1      3    3
                     10  1 69  3  3 3  3   3   3  3   1   1  1      3    3
                     10 17 69  3  3 3  3   3   3  3   1   1  1      3    3
                     10 29 69  3  3 3  3   3   3  3   1   1  1      3    3
                     11 12 69  3  3 3  3   3   3  3   1   1  1      3    3
                     12  3 69  3  3 3  3   3   3  3   1   1  1      3    3
                     12 15 69  3  3 3  3   3   3  3   1   1  1      3    3
                       1 2 70  3  3 3  3   3   3  3   1   1  1      3    3
                       126 70  3  3 3  3   3   3  3   3   3  3      3    3
                       211 70  3  3 3  3   3   3  3   3   3  3      3    3
                       225 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       311 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       325 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       4 8 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       422 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       5 6 70  3  3 3  3   3   3  3   3   3  3      3    3             3
                       520 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       6 3 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       617 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       7 1 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       715 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       730 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       812 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       826 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       910 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       923 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     10  7 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     10 22 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     11  4 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     11 19 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     12  3 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     12 17 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                     12 30 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       114 70  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       2 5 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       218 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       3 5 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       331 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       416 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3
                       428 71  3  3 3  3   3   3  3   3   3  3      3    3   3  3      3

                 186                                                             Appendices

                 Appendix 4, 1. Continued

                   sample               Parameters Sampled and Data Sources
                   Date

                 MO DA YR  ST  BT SS BS SDO BDO PH P04 TDP TP PP N03 NH4 TDN TN PN CHL

                   512 71   3  3 3  3   3   3  3   3    3  3      3   3   3  3      3
                   526 71   3  3 3  3   3   3  3   3    3  3      3   3   3  3      3
                   6 9 71   3  3 3  3   3   3  3   3    3  3      3   3   3  3      3
                   624 71   3  3 3  3   3   3  3   3    3  3      3   3   3  3      3
                   7 8 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   721 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   8 4 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   831 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   915 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 10  6 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 10 20 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 11 10 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 11 23 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 12 13 71   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   1 4 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   119 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   2 3 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   223 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   3 8 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   323 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   4 6 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   419 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   522 72   4  4A   4   4   4  4   4    4  4      4   4   4  4      4
                   614 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   719 72'  4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   8 9 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   9 7 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 10  5 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 10 18 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 11  1 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                 12  6 72   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   119 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   221 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   321 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   4 4 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   419 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   7 9 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   726 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   822 73   4  4 4  4   4   4  4   4    4  4      4   4   4  4      4
                   127 75   5  5 5  5   5   5  5   5    5  5      5   5   5  5      5
                   214 75   5  5 5  5   5   5  5   5    5  5      5   5   5  5      5
                   228 75   5  5 5  5   5   5  5   5    5  5      5   5   5  5      5
                   328 75   5  5 5  5   5   5  5   5    5  5      5   5   5  5      5

                      Appendices                                                                   187
                      Appendix 4. 1. Continued

                       Sample                 Parameters Sampled and Data Sources
                        Date

                      MO DA YR  ST BT  SS BS SDO BDO PH P04 TDP  TP PP N03 NH4 TDN  TN PN CHL

                       4 17 75   5  5  5 5    5   5  5   5   5   5      5   5    5  5      5
                       5 19 75   5  5  5 5    5   5  5   5   5   5      5   5    5  5      5
                       5 30 75   5  5  5 5    5   5  5   5   5   5      5   5    5  5      5
                       6 18 75   5  5  5 5    5   5  5   5   5   5      5   5    5  5      5
                       6 24 75   5  5  5 5    5   5  5   5   5   5      5   5    5  5      5
                       7 11 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       7 21 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       8   275  17     17
                       8   575   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       8 16 75  17     17
                       8 19 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       9   275   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       9   675  17     17     17
                       9 18 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                      10   675  17     17     17
                      10 10 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                      10 19 75  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                      10 21 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                      11   575   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                      11   575  17     17     17
                      11   975  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                      12   575   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                      12   775  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                      12   975  17     17     17
                      12 14 75  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                      12 15 75  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                      12 17 75   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       1 12 76   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       1 15 76  17     17     17
                       2 24 76   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       2 26 76  17     17     17
                       2 27 76  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                       3 11 76   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       3 24 76  16  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       3 25 76  17     17     17
                       4   376  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                       4   476  18 18  18 18  18  18 18  18  18  18 18  18  18   18 18 18
                       4   676   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       4 21 76   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       5   576   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       5 11 76  17     17     17
                       6   776   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6
                       6 23 76   6  6  6 6    6   6  6   6   6   6      6   6    6  6      6

                  188                                                                Appendices

                  Appendix 4. 1. Continued

                   Sample                 Parameters Sampled and Data Sources
                    Date

                  MO DA YR ST  BT SS BS SDO BDO PH P04 TDP TP PP N03 NH4 TDN     TN PN CHL

                   6 23 76 17     17      17
                   7  6 76 6    6 6  6    6   6  6   6    6  6      6    6   6   6      6
                   7 19 76 6    6 6  6    6   6  6   6    6  6      6    6   6   6      6
                   7 25 76.18  18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   7 26 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   7 27 76  17    17      17
                   8 11 76  17    17      17     17  17   17 17 17  17   17  17  17 17  17
                   8 15 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   8 16 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   8 23 76   6  6 6  6    6   6  6   6    6  6      6    6   6   6      6
                   9  5 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   9  6 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   9  9 76   6  6 6  6    6   6  6   6    6  6      6    6   6   6      6
                   9 24 76   6  6 6  6    6   6  6   6    6  6      6    6   6   6      6
                   9 26 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   9 27 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  10  7 76   6  6 6  6    6   6  6   6    6  6      6    6   6   6      6
                  10 16 76  17    17      17     17  17   17 17 17  17   17  17  17 17  17
                  10 17 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  10 18 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  11  5 76   7  7 7  7    7   7      7    7  7      7    7   7   7      7
                  11 14 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  11 15 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  12  5 76  17    17      17     17  17   17 17 17  17   17  17  17 17  17
                  12 10 76   7  7 7  7    7   7      7    7  7      7    7   7   7      7
                  12 12 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                  12 13 76  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   1  8 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   1  9 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   1 10 77   7  7 7  7    7   7  7   7    7  7      7    7   7   7      7
                   1 30 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   2  4 77   7  7 7  7    7   7  7   7    7  7      7    7   7   7      7
                   2  5 77  18 18 18 18   18  18 18  .18  18 18 18  18   18  18  18 18
                   2  9 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   2 19 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   2 20 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   3  2 77  17 18 17 18   17  18 17  17   17 17 17  17   17  17  17 17  17
                   3  2 77  18    18      18     18  18   18 18 18  18   18  18  18 18
                   3 10 77   7  7 7  7    7   7  7   7    7  7      7    7   7   7      7
                   3 12 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   3 13 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18
                   3 30 77   7  7 7  7    7   7  7   7    7  7      7    7   7   7      7
                   4  2 77  18 18 18 18   18  18 18  18   18 18 18  18   18  18  18 18

                      Appendices                                                                   189

                      Appendix 4. 1. Confinued

                       sample                 Parameters Sampled and Data Sources
                        Date

                      MO DA YR  ST BT SS BS SDO BDO  PH P04 TDP  TP PP N03 NH4 TDN  TN PN CHL

                       4  3 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       4 14 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       4 25 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       4 24 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       4 26 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       5 12 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       5 15 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       5 16 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       5 23 77  17    17      17     17  17  17  17 17  17  17   17 17 17  17
                       6  5 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       6  6 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       6  8 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       6 30 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       7  7 77  17    17      17     17  17  17  17 17  17  17   17 17 17  17
                       7 10 77  18 18 18 18   18  18 18  18  18  18 18  18  18   18 18 18
                       7 11 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       7 25 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       8 10 77   7  7 7  7    7   7  7   7   7   7      7   7    7  7      7
                       9  9 77   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       9 29 77   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                      11  9 77   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                      12 16 77   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       1 10 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       2 15 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       3 17 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       4  7 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       4 28 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       5 11 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       5 23 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       6  7 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       6 20 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       7 13 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       7 26 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       8 15 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                       8 23 78   8  8 8  8    8   8  8   8   8   8      8   8    8  8      8
                      10 23 78   *  * *  *
                      11  9 78   *  * *  *
                      11 29 78   *  * *  *
                      12 14 78   *  * *  *
                       2 16 79   9  9 9  9    9   9  9   9   9   9      9   9    9  9      9
                       3 16 79   9  9 9  9    9   9  9   9   9   9      9   9    9  9      9
                       4 25 79   9  9 9  9    9   9  9   9   9   9      9   9    9  9      9
                       5  8 79   9  9 9  9    9   9  9   9   9   9      9   9    9  9      9

                 190                                                              Appendices

                 Appendix 4. 1. Continued

                  Sample                Parameters Sampled and Data Sources
                   Date

                 MO DA YR  ST BT SS BS SDO BDO PH P04 TDP TP PP N03 NH4 TDN  TN PN CHL

                  5 28 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  6  7 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  6 14 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  7 17 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  7 24 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  8 22 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  8 28 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  9 20 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  9 27 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                 10  2 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                 10 18 79   9  9 9  9   9   9  9   9   9  9       9   9   9  9      9
                  1 17 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  2 15 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  2 28 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  3 27 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  3 31 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  4 16 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  4 28 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  5  6 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  5 19 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  6  2 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  6 16 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  7  7 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  7 14 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  8  1 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  8 14 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  8 25 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  9  9 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  9 29 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                 11  4 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                 11 20 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                 12  4 80  10 10 10 10  10  10 10  10  10 10      10  10  10 10     10
                  1 16 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  1 29 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  2 16 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  2 27 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  3  9 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  3 25 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  4  7 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  4 22 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  5 15 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  6 10 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11
                  6 22 81  11 11 11 11  11  11 11  11  11 11      11  11  11 11     11

                     Appendices                                                                191
                     Appendix 4. 1. Continued

                       Sample               Parameters Sampled and Data Sources
                       Date

                     MO DA YR ST  BT SS BS  SDO  BDO PH  P04  TDP TP PP N03  NH4  TDN TN PN CHL

                       7 7 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       716 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       729 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       825 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       910 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       918 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     10  1 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     10  9 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     10 22 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     11  3 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     12  4 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                     12 23 81 11  11 11 11  11  11 11  11  11 11     11   11  11 11     11
                       1'7 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       220 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       211 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       224 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       3 9 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       319 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       4 2 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       5 3 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       511 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       524 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       610 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       625 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       716 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       722 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       8 5 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       819 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       9 1 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       916 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     10  8 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     10 21 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     10 29 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     11 10 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     11 30 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                     12 15 82 12  12 12 12  12  12 12  12  12 12     12   12  12 12     12
                       1 6 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       125 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       2 9 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       216 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       222 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       310 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13
                       4 1 83 13  13 13 13  13  13 13  13  13 13     13   13  13 13     13

                 192                                                              Appendices
                 Appendix 4. 1. Continued

                   Sample               Parameters Sampled and Data Sources
                   Date

                 MO DA YR ST BT SS  BS  SDO  BDO PH  P04  TDP TP PP N03  NH4  TDN TN PN CHL

                   412 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   422 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   5  583 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   5  683 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   6  283 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   613 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   630 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   712 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   727 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   8  883 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   831 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   9  883 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   923 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                 10   483 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                 11   383 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                 11 17 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                 11 22 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                 12 29 83 13 13 13  13  13  13 13  13  13 13      13  13  13 13     13
                   1  684 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   126 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   2  284 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   215 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   3  884 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   316 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   327 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   420 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   427 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   5  984 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   523 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   6  884 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   621 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   7  584 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   720 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   8  284 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   815 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   829 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   921 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                   926 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                 10 10 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                 10 24 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                 11 14 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                 11 27 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14
                 12 13 84 14 14 14  14  14  14 14  14  14 14      14  14  14 14     14

                     Appendices                                                                193
                     Appendix 4. 1. Continued

                      sample                Parameters Sampled and Data Sources
                       Date

                     MO DA YR  ST BT SS BS  SDO  BDO PH  P04  TDP TP PP  N03  NH4  TDN TN PM  CHL

                     12 19 84  14 14 14 14  14  14 14  14  14 14     14  14  14 14      14
                      2  6 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      2 21 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      3 28 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      4 12 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      4 24 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      4 30 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      5  7 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      5 21 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      5 31 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      6 11 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      6 20 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      7  9 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      7 17 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      8  1 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      8  6 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      8 19 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      8 28 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      9 19 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      9 30 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                     10 14 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                     11 15 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                     11 26 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                     12  9 85  15 15 15 15  15  15 15  15  15    15  15  15  15     15  15
                      1 15 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      2  4 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      2 18 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      3 26 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      4  2 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      4 17 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      5  1 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      5  8 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      5 22 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      6  4 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      6 19 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      7 10 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      7 16 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      7 30 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      8 13 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      8 27 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      9 10 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                      9 24 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16
                     10  8 86  16 16 16 16  16  16 16  16  16    16  16  16  16     16  16

                  194                                                                Appendices
                  Appendix 4. 1. Continued

                  Sample                 Parameters Sampled and Data Sources
                   Date

                  MO DA YR ST BT SS BS SDO BDO PH P04 TDP TP PP N03    NH4 TDN TN PN CHL

                  10 30 86 16 16 16 16   16  16 16   16  16     16  16  16  16     16  16
                  11  7 86 16 16 16 16   16  16 16   16  16     16  16  16  16     16  16
                  12  9 86 16 16 16 16   16  16 16   16  16     16  16  16  16     16  16
                  12 27 86 16 16 16 16   16  16 16   16  16     16  16  16  16     16  16

                       Appendices                                                                            195
                       Appendix 4.2. Pamlico River estuary water quality sampling station locations

                       Note 1. Sample station numbers are arranged by investigator (columns)
                       and river segment (A-J) (rows).

                       Note 2. Investigator codes:        Hl =  Hobbie (March 1967-February 1968)
                                                          H2 =  Hobbie (June 1968-July 1969)
                                                          H3 =  Hobbie (July 1969-July 1971) -
                                                          H4 =  Hobbie (August 1971-August 1973)
                                                          Dl =  Davis (August 1975-July 1976)
                                                          D2 =  Davis (August 1976-July 1977)
                                                          K  =  Kuenzler (1975-1977)
                                                          Il =  ICMR (January 1975-June 1975)
                                                          12 =  ICMR (July 1975-December 1986)
                                                                Station 7 sampled 1/77-12/86
                                                                Station 2N sampled 7/75-7/77
                                                                Station 1A sampled 7/80-12/86

                       Note 3. The "location" notes below refer to geographic features named
                       on National Ocean Survey Charts 11554 (13th. ed., 1981) and 11548 (31st.
                       ed., 1985), published by the U.S. Department of Commerce, National
                       Oceanic and Atmospheric Administration (NOAA),            Washington, D.C.

                        River
                       Segment         Investigator

                             H1 H2 H3 H4 D1 D2 K Il 12             Latitude/Longitude/Location

                          A                   22   1     11 12    N35032 I 07"-W77002 155"
                                                                  Mid-river, RR bridge     at Washington

                          A                   21            11    N35029151 "-W77001138"
                                                                  Mouth of Chocowinity     Bay

                          B                              10 10    N35028155 "-W76059115 "
                                                                  Marker "12" off Camp     Hardee

                          B      H17 H17    1                     N35'28122 "-W76058,27 "
                                                                  Marker "10", mid-river off Hills Pt.

                     196                                                                         Appendices

                   Appendix 4.2. Continued

                     River
                    Segment        Investigator

                         H1 H2 H3 H4 D1 D2 K Il 12               Latitude/Longitude/Location

                      B                                    9S   N350271 04 "-W76057 132 "
                                                                South Blounts Bay

                      B                                    9N   N35028150 "-W76057 124 "
                                                                Marker "1", mouth of Broad Ck.

                      B      H16 H16 2 20 2         1           N35027 142"-W76057 133"
                                                                Marker "9", Blounts Bay

                      B             A5                          N350281 00 "-W760581 00"
                                                                West Blounts Bay

                      C                 3                       N35027 1 27 "-W760561 11
                                                                Marker "8", NW of Maules Pt.

                      C      H11 H11                   9    8   N350271 10"-W76055 1 10"
                                                                Marker "7", NE of Maules Pt.

                      C                 4 19                    N35026142 "-W76054 113 "
                                                                Test Well "D" off Jack Ck.

                      C    3                                    N35027 120"-W76053 135 "
                                                                Off Mallard Ck., N side of river

                      C    2                                    N35026148"-W76053137"
                                                                Between Tripp Pt. and Mallard Ck.

                      C    1                                    N350261 10"-W760531 40"
                                                                Off Tripp Point, south side of river

                      D      H10 H10    5 18       2   8        N35026130"-W76052 1 22"
                                                                Between Sparrow Bay and Duck Ck.

                      D    4                                    N35026145 "-W76050145
                                                                Off Hawkins Landing, N side of river

                      D       H9 H9        16               7   N35025 I 50"-W76050130"
                                                                Marker "5" off Core Pt.

                         Appen.dices                                                                                  197
                         Appendix 4.2. Continued

                           River
                          Segment         Investigator

                                Hl H2 H3 H4 Dl D2 K Il 12                Latitude/Longitude/Location

                            D                  6                       N350261 03"-W760501 05
                                                                       Mid-river between Core Pt. and Bath Ck.

                            D    5                                     N350261 10"-W76050150"
                                                                       Between Hawkins Lndg. and Core Pt.

                            D    6                                     N35025 143 "-W76050151 "
                                                                       off Core Pt., near s. shore of river

                            D                                    7S    N35024 1 04 "-W76049, 04 "
                                                                       Marker "2" at mouth of Durham Ck.

                            D                     17             7N    N35027 103 "-W76049 115"
                                                                       Marker "1" at mouth of Bath Ck.

                            D        H8   H8   8               7       N35024 145 "-W76048,43 "
                                                                       Mid-river between TG and Bayview

                            D       SH8 SH8    9  15                   N35024108 "-W76048140 "
                                                                       off mouth of Durham Creek

                            D                          3   3           N35025 115 "-W76048130"
                                                                       Mid-river between Durham Ck. & Bath Ck.

                            D    7                                     N35023 145 "-W76047 152 "
                                                                       Off TG, near south shore

                            D    10               14                   M350251 55 "-W76047 140"
                                                                       Off Bayview, near north shore

                            D    8                                     N35024 120"-W76047 145 "
                                                                       Off TG, near south shore

                            D    9                                     N350251 05 "-W76047 145"
                                                                       Mid-river between TG and Bayview

                    198                                                                          Appendices

                   Appendix 4.2. Continued

                    River
                    Segment        Investigator

                         Hl H2 H3 H4 Dl D2 K Il 12               Latitude/Longitude/Location

                      D      NH8 NH8 7                          N3502513 0"-W7 604 613 6"
                                                                off Mixon Creek, N side of river

                      E                                     6   N35023112"-W76046107 "
                                                                Off TG outfall

                      E      SH7 SH7 12                         N35023128 "-W76046,20 "
                                                                Marker "1" at TG barge canal

                      E       H7 H7 11                          N350241 10 "-W76046103"
                                                                Between Gum Pt. and TG barge canal

                      E      NH7 NH7 10                         N35024147 "-W76045152 "
                                                                Marker "4" off Gum Pt.

                      E            A3 14                        N35023 157 "-W76044 139
                                                                Between St. Clair Ck. and Long Pt.

                      E  14                11          5 5S     N35023103"-W76044 139"
                                                                Marker "1" at Ferry Landing

                      E  12                                     N35024137 "-W76044125"
                                                                Between Gaylord Bay and Ferry Lndg.

                      E                    12       4  6 5      N35024110"-W76044118"
                                                                Between Gaylord Bay and Huddles Gut

                      E            A2 13                        N35025 I 10"-W76044135"
                                                                Off St. Clair Ck., N side of river

                      E  13                                     N35024145"-W76044,35"
                                                                off ferry landing, south side of river

                      E  11                13              5N   N35025119"-W76044110"
                                                                Marker "i" in Gaylord Bay

                        Appendices                                                                            199

                        Appendix 4.2. Continued

                         River
                         Segment        Investigator

                              H1 H2     H3 H4 Dl D2 K Il 12         Latitude/Longitude/Location

                           E  15                                   N35022 103 "-W76041140 "
                                                                   Off Hickory Pt., south side of river

                           E           A4 15                       N35023 I 00"-W76041140 "
                                                                   Off Long Pt., S side of river

                           E  17                                   N35023 125 "-W76041, 10"
                                                                   Between Cousin Pt. and Hickory Pt.

                           E  16                                   N35022 147 "-W76041122
                                                                   Off Hickory Pt., S side of river

                           E  18                                   N35024 I 03"-W76040,55 "
                                                                   Off Cousin Pt., N side of river

                           E  19                                   N35024 140"-W760401 45"
                                                                   Off Cousin Pt., N side of river

                           F  26                                   N35021122 "-W76041, 05 "
                                                                   Marker "5" off South Ck.

                           F  25  H13 H13 32                 4S    N35021128"-W76040,37 "
                                                                   Marker "4" off South Ck.

                           F       H6 H6 17                        N35023 145 "-W76040,16"
                                                                   Between Hickory Pt. & Cousin Pt.

                           F      NH6 NH6 16                 4N    N35024 146"-W760401 11 "
                                                                   Marker "1" at mouth of North Ck.

                           F      SH6 SH6 18                       N35022 130"-W76040,29 "
                                                                   Between Hickory Pt. & Cousin Pt.

                           F  24               10                  N35021120 "-W76039135 "
                                                                   South of Indian island

                           F  23                                   N35021155 "-W760391 00 "
                                                                   North of Indian Island

                    200                                                                       Appendices

                   Appendix 4.2. Continued

                    River
                    Segment        Investigator

                         Hl H2     H3 H4 Dl D2 K Il 12         Latitude/Longitude/Location

                      F 21                                    N35023103 "-W7603 8120 "
                                                              North of Indian Island

                      F 22 H5 H5           9 4        4 3     N35022123 "-W76038,47 "
                                                              Marker "3", north of Indian Island

                      F  20                8                  N35023 140"-W760381 07 "
                                                              North of Indian Island

                      F      H12 H12                          N35021112 "-W76038,25 "
                                                              Marker "2" south of Indian Island

                      G      SH4 SH4  20                      N350211 10"-W76037 1 00"
                                                              Off Reed Hammock

                      G      NH4 NH4  19                      N35022 136"-W76036,06"
                                                              Off Cousin Pt., north side of river

                      G  35                                   N35020,36"-W76036,32"
                                                              Off Reed Hammock, s. side of river

                      G       H4 H4               5           N35022 I 00"-W76036130"
                                                              Between Reed Hammock and Adams Pt.

                                                      3       N3502114 0 " -W7 603 6119 "
                                                              Mid-river between Wades Pt. & Goose Ck.

                      G  34                                   N35021,02"-W76036,08"
                                                              Between Reed Hammock and Wades Pt.

                      G                    5            2S    N35020'22 "-W76035 147"
                                                              Marker "1" at mouth of Goose Ck.

                         Appendices                                                                               201

                        Appendix 4.2. Continued

                          River
                          Segment        Investigator

                               H1 H2     H3 H4 D1 D2 K 11 12          Latitude/Longitude/Location

                           G 33                                      N35021124 "-W76035,48
                                                                     Mid-river between Wades Pt. & Reed Ham.

                           G 31                                      N35022124 "-W76035 1 00"
                                                                     Between Reed Hammock and Wades Pt.

                           G   32                 6                  N35021152 "-W76035 124 "
                                                                     Between Reed Hammock      and Wades Pt.

                           G   30                 7                  N35022 154"-W76034 142"
                                                                     Off Wades Pt.

                           G                 21                      N35022138 " -W76033124"'
                                                                     Marker "PR" at mouth of Pungo R.

                           G                 23                      N35020118"-W76033 154 "
                                                                     Between Goose Ck. and Cedar Is.

                           G                 22                      N35021124 "-W76033 133 "
                                                                     Mid-river south of mouth of Pungo R.

                           H              Al 31                2N    N35023 136"-W76033 1 00"
                                                                     At mouth of Pungo River

                           H      SH3 SH3    26                      N350201 00 "-W76032 1 06"
                                                                     North of Cedar Island

                           H        H3 H3    25      5       2 1A    N35021120"-W76031,30 "
                                                                     Mid-river between Abel B. & Cedar Is.

                           H      NH3 NH3    24                      N35023113 "-W76030130"
                                                                     S. of Indian Is. Marker "1" at Abel B.

                           1   38                                    N35020154 "-W76029114 "
                                                                     Between Marker "1" and Willow Pt.

                    202                                                                       Appendices

                   Appendix 4.2. Continued

                    River
                    Segment        Investigator

                         H1 H2     H3 H4 D1 D2 K Il 12         Latitude/Longitude/Location

                      1  37                                   N35019152 "-W76029,12
                                                              Between Pamlico Pt. & Willow Pt.

                      1  39  NH2 NH2 27    2                  N35021148 " -W76028150 "
                                                              Marker at Willow Pt. shoal

                      1  36  SH2 SH2 29    4                  N35019,00"-W76028158"
                                                              Marker "i" at Pamlico Pt.

                      I       H2   H2 28   3                  N35020130"-W76028 1 54 "
                                                              Mid-river between Willow Pt. & Pam. Pt.

                      1                30             1   1   N35020106"-W76027136"
                                                              Mid-river between Pam. Pt. & Rose Bay

                      I       Hl   H1      1   6  6           N35018 147 "-W76027 120"
                                                              Pamlico Pt. light

                      1  29                                   N350201 31 "-W76044 119"
                                                              Marker "9" in South Creek

                      i      H15 H15 34                       N350211 09"-W76043 143"
                                                              Marker "8" in South Ck.

                      J  28                                   N350211 03 "-W76042 120"
                                                              off Old Field Pt., South Creek

                      i      H14 H14 33              12 4P    N35021114"-W76042115"
                                                              Marker "7", South Ck.

                      J  27                                   N35020145"-W76041140"
                                                              Marker "2", mouth of Bond Creek

                         Appendix 4.3.
                         Changes in sampling and analytical methods

                             To the best of my knowledge, all the       al. (1978) used a salinity-conductivity-tem-
                         hydrographic and nutrient data reported        perature (SCT) meter (Model 33) manu-
                         by Hobbie for the period 1967-1973 were        factured by Yellow Springs Instrument
                         from analyses carried out by students and      Company (YSI). Beginning in 1975, and
                         research technicians at the Pamlico Estua-     continuing to the present, the ICMR moni-
                         rine Laboratory (PEL) near Aurora, NC.         toring program at ECU has also made use
                         After East Carolina University (ECU) took      of the YSI SCT meter for temperature and
                         over the monitoring program in 1975, the       salinity measurements. There is no reason
                         analyses continued to be performed at the      to suspect that data from these two instru-
                         PEL under the supervision of Mr. Dan           ments are incomparable. All the data have
                         Kornegay. In mid- 1980 the procedure was       been reported in units of OC for tempera-
                         changed so that samples were transported       ture, and parts per thousand (ppt) for Sa-
                         to the Institute for Coastal and Marine        linity.
                         Resources on the ECU campus in Greenville          Dissolved oxygen measurements in
                         for analysis. Finally, in March 1985 analy-    the Pamlico studies have been made by
                         sis of the Pamlico samples was shifted to      two methods: 1) the classical Winkler titri-
                         the ECU Biology Department's Central           metric technique, and 2) oxygen sensing
                         Environmental Laboratory, under the su-        electrodes. The Winkler method was used
                         pervision of Ms. Martha Jones. Samples         for all the dissolved oxygen analyses re-
                         collected by Davis et al. (1978) were also     ported by Hobbie. Water samples were
                         analyzed in the ECU Biology Department         taken with a Kemmerer sampler, fixed in
                         lab. Kuenzler et al. (1979) transported        the field, and titrated in the laboratory. No
                         their samples to the U.N.C. Chapel Hill        other details of the procedure are given in
                         campus foranalysis in the Limnology LabO-      Hobbie's reports. Instead, the reader is
                         ratory of the Department of Environmen-        referred to Carpenter (1965), who described
                         tal Sciences and Engineering.                  the method as "a modified ... Winkler
                                                                        determination", and he detailed the modi-
                            Water Temperature, Salinity, Dis-           fications, most of which involve the titra-
                         solved Oxygen, and pH: Two kinds of            tion equipment. Kuenzler at al. (1979)
                         instruments have been used to measure          used an "APHA-type" oxygen sampler to
                         water temperature and salinity in the          collect replicate D.O. samples from 0.5 in
                         Pamlico studies. Hobbie used a conductiv-      below the surface and 0.5 in above the
                         ity bridge with built-in thermistor            bottom. Samples were fixed by the addi-
                         (Beckman RS5-3 induction salinometer) to       tion of manganous sulfate and alkaline
                         measure salinity and temperature in situ,      iodide for Winkler analysis by procedures
                         except for a few times in 1967 when hy-        given in American Public Health Associa-
                         drometers were used for salinity measure-      tion (1975). Davis et al. (1978) and ICMR
                         ment. Presumably a mercury thermom-            both measured dissolved oxygen by means
                         eter was used on these occasions to mea-       of a Yellow Spring Instrument Company
                         sure water temperature, although such is       Model 51A oxygen meter and electrode.
                         not stated in the report (Hobbie 1970b).           All of the Hobbie dissolved oxygen data
                         The induction salinometer was used also        was reported as ml 02/liter. To permit
                         by Kuenzler et al. (1979) in their Pamlico     comparison with later data, I have con-
                         samplingin 1975,1976 and 1977. Davis et        verted the ml 02/liter values to mg02/liter,

                     204                                                                            Appendices
                     by multiplying times 1.429 (Head 1985).         was measured in the laboratory, but since
                     Dissolved oxygen (DO) percent saturation        then a portable instrument has been used
                     values were included for some years in the      to make measurements on freshly-drawn
                     previous Pamlico reports, but the method        samples in the field (Stanley 1987).
                     ofealculation was not always given. There-
                     fore, in order to have the data for all years       Nitrogen and Phosphorus: Proce-
                     and to insure consistency, I have recalcu-      dures for the collection ofsamples, for nitro-
                     lated percent saturations (DOPS) by the         gen and phosphorus analyses have varied
                     following formula:                              somewhat among the four studies. Hobbie
                       I DOPS = (mgDO/liter * 100XDO Satu-           stated simply that "surface samples were
                     ration Value),                                  taken at each station and returned to the
                         where                                       laboratory for analysis" (Hobbie 1970a,
                         DO Saturation Value = (475 - (2.65 *        page6). Davisetal. (1978) collected samples
                     S)X33.3 + T).                                   0.5 m below the surface, immediately fil-
                         S is salinity (ppt) and T is the tempera-   tered aliquots for dissolved nutrients, and
                     ture (OC). This is the same formula used by     stored all the samples in the dark on ice for
                     Hobbie (1970b) forsomeofthe earlyPamlico        transport back to the laboratory. Kuenzler
                     data. He indicated that it was developed        et al. (1979) filled polyethylene carboys
                     by Truesdale and Gameson (1957).                with water from a depth of 0.5 m by means
                         Of course, no percent saturation values     of a Guzzler R Pump (Cole-Parmer Instru-
                     could be calculated when there was not a        ment Company) fitted with a plastic hose
                     dissolved oxygen value. However, in those       covered at the intake end with 153 um
                     few cases where there was a DO value, but       mesh nylon netting to exclude zooplank-
                     no temperature and/or salinity data, I did      ton. The samples were returned to the
                     estimate the percent saturation. I did this     Pamlico Estuarine Laboratory (PEL)
                     by interpolating to give the missing salin-     within a few hours for filtration, followed
                     ity or temperature values needed for the        by freezingand transport to Chapel Hill for
                     calculation.                                    later analysis. Finally, samples collected
                       . I have not found in any of the Hobbie       since 1975byICMR were taken by dipping
                     reports a description of the method used        1-liter polyethylene bottles into the water
                     for pH measurements. However, I believe         just below the surface. The bottled samples
                     that a pH meter with electrode (model           were held on ice in the dark until they were
                     unknown) was used, and that measure-            returned to either the PEL or ECU (within
                     ments were made on samples after they           6 hours of collection), where they were
                     were returned to the Pamlico Estuarine          filtered and frozen (e.g., ICMR 1982;
                     Laboratory, usually within a few hours          Stanley 1987).
                     after collection. Davis et al. (1978) stored        Other variables associated with the
                     samples in the dark at mean ambient             nutrient sample processing include the
                     water temperature for up to 4 hours until       type of filter used to separate dissolved and
                     pH could be measured with a Corning             particulate fractions, and the type and
                     Model 10 meter. Kuenzler at al. (1979) also     length of storage of samples between col-
                     used a pH electrode, but I don't recall the     lection and analysis. Hobbie used Gelman
                     meter model; no reference to it is made in      A glass fiber filters. Reactive phosphorus
                     the project report. Since 1975 various pH       was measured as soon as the samples were
                     meters with electrodes (manufacturers and       returned to the laboratory, but water (fil-
                     models have varied) have been used for the      tered and unfiltered) for the total phospho-
                     ICMR pH measurements. Until 1985 pH             rus, total dissolved phosphorus, and nitro-

                         Appendices                                                                                  205

                         gen fractions was frozen in plastic bags         in 1969 that the calibration curve was not
                         immediately after collection byplacingthe        linear above 10 ug-at P/liter and the previ-
                         bags onto dry ice (Hobbie et al. 1972).          ous readings obtained were underesti-
                         Similarly, Kuenzler et al. (1979) filtered       mates. Therefore, the concentrations mea-
                         samples through Whatman GF/C glass               sured prior to 14 October 1969 are low and
                         fiber filters and stored the filtered (or        can be corrected by multiplying by a factor
                         unfiltered) water frozen in polyethylene         of 1.0 at 10 ug-at P/liter and 1.6 at 20 ug-
                         until the nutrient analyses were run.            at P/liter. Since this correction makes no
                         Gelman type A/E glass fiber filters were         difference to the conclusions of this report,
                         used by Davis et al. (1978), and they also       it was not applied to the data. It was also
                         froze the samples pending analyses of nu-        found that the curves for total (digested)
                         trients. Since 1984 Whatman 934-AH               and reactive (undigested) phosphate con-
                         glass fiber filters have been used for the       centrations versus extinction had different
                         samples analyzed in the ICMR program.            slopes. Again the differences are slight,
                         There is no record of the kind of filters used   but this correction and the correction for
                         between 1975 and 1983. Both filtered and         the differing factors at high concentrations
                         unfiltered samples have been stored fro-         of phosphorus will clear up most of the
                         zen, for up to several months in some            discrepancies of the data where the reac-
                         instances, until the analyses were made.         tive phosphorus is higher than the total
                             1. Phosphorus: Nearly all the samples        phosphorus" (Copeland and Hobbie 1972,
                         taken during these studies were analyzed         pages 24-25).
                         for at least three phosphorus fractions;            Apparently the phosphorus methodol-
                         total phosphorus (TP), total dissolved phos-     ogy did not change between 1969 and
                         phorus (TDP), and orthophosphate phos-           August 1973 when Hobbie's sampling
                         phorus (OK TP analyses were performed            ended, since his 1974 report on the 1971-
                         on unfiltered water samples, while the           1973 data states on page 12 that "details of
                         other two measurements used filtered             the phosphorus analysis are given in Hobbie
                         water. All the TP and TDP samples were           (1970a)", and the references he cites re-
                         first digested by some variation of the          garding methodology are the same ones
                         persulfate oxidation method of Menzel and        cited in the earlier report; i.e., Menzel and
                         Corwin (1965). Subsequent analyses of            Corwin (1965) for the persulfate digestion
                         these digested samples, and undigested           and Strickland and Parsons (1968) for the
                         orthophosphate samples, was by manual            use of the mixed reagent. The same spec-
                         or automated colorimetric methods. All           trophotometer that had been used earlier
                         projects used the mixed reagent developed        was used to read the sample color following
                         by Murphy and Riley (1962), containing           addition of the mixed reagent.
                         ammonium molybdate, ascorbic acid, and              Davis et al. (1979) seem to have used
                         trivalent antimony.                              the same basic procedure as Hobbie, al-
                             Copeland and Hobbie give further de-         though they reported few details regard-
                         tails on the methodology used between            ing their phosphorus methodology. They
                         1967 and 1969: "The color development            simply state that "phosphorus analyses
                         was read in a Beckman DU II spectropho-          involved conversion of phosphorus to or-
                         tometer and the optical density calibrated       thophosphate by persulfate digestion, and
                         against standards. These standards proved        subsequent colorimetric determination of
                         to be constant and a factor of 5.0 multiplied    soluble orthophosphate." They cite the
                         by this spectrophotometer reading gave           manual on water and wastewater chemi-
                         the concentration. However, it was noted         cal analyses published by the Environ-

                     206                                                                              Appendices
                     mental Protection Agency (EPA) (1976) as         the annual reports to Texasgulf (Stanley
                     a reference to their procedures. The meth-       1986a, 198b, 1987). The most significant
                     ods outlined in this document do indeed          change in recent years came in 1985 when
                     involve the use of persulfate digestion for      the procedures were automated using a
                     TDP and TP and the use of the three-part         Scientific Instruments autoanalyzer simi-
                     mixed reagent for phosphate determina-           lar to the Technicon equipment used ear-
                     tion.                                            lier by Kuenzler et al. (1979). Details of the
                        An earlier edition of the EPA manual          autoanalyzer procedure are given in
                     (1974) was referenced by Kuenzler et al.         Stanley (1987).
                     (1979) to describe the phosphorus method-            On 28 March 1985 the total phospho-
                     ology they used for Pamlico samples ana-         rus analysis was dropped and particulate
                     lyzed in their study between 1975 and            phosphorus (PP) measurements were be-
                     1977. They used slightly different termi-        gun. PP is the fraction of TP that remains
                     nology to describe the phosphorus frac-          on the filter pad following filtration. There-
                     tions - "filterable reactive P" instead of       fore, the total phosphorus data used in this
                     orthophosphate phosphorus, and "total fil-       study for the period 28 March 1985 through
                     terable P" instead of total dissolved phos-      December 1986 are not direct measure-
                     phorus. The main difference between their        ments, but rather the sums of the total
                     procedure and that of Hobbie and Davis et        dissolved phosphorus and PP values.
                     al. was that they automated the analyses             It has been determined recently that
                     using Technicon Autoanalyzer equipment.          all the total dissolved phosphorus (TDP)
                     They state in their report that ". . . preci-    data presented in the 1986 annual report
                     sion was controlled in these analyses by         (Stanley 1987) and part of the data in the
                     runningall samples in duplicate. Accuracy        1985 report (Stanley 1986b) are in error.
                     was checked in two ways. Where avail-            This error arose duringthe transition from
                     able, EPA controls were analyzed with            manual to automated methods of analysis
                     every run. Also approximately 10% of             of TDP during 1985. The problem is that
                     routine analysis time was spend [sic] de-        the automated analysis gives erroneously
                     termininarecoverv of known increments of         high TDP results. The solution to this
                     standar& (spike;) to samples. . . Stan-          problem is described above in the Methods
                     dards were routinely run at the beginning        section of the report.
                     and end of each sample run" (Kuenzler et             2. Nitrogen: From 1969 through 1973
                     al. 1979, pages 17-19). .                        Hobbie analyzed several nitrogen fractions,
                         Finally, all ICMR samples from 1975 to       including nitrate nitrogen, ammonia ni-
                     the present have been analyzed for phos-         trogen, total dissolved nitrogen (TDN), and
                     phorus using the same basic chemistry            total nitrogen (TN). The first three analy-
                     described above; i.e., the mixed color re-       ses were run on filtered samples, while the
                     agent for OP and persulfate digestion to         fourth (TN) used unfiltered water. Hobbie
                     convert TP and TDP to OP. Notes provided         (1974) referred to the total dissolved nitro-
                     to me by the analyst who performed the           gen as "total filtered nitrogen", and to the
                     tests from 1975 through 1980 show that           total nitrogen as "total unfiltered nitro-
                     EPA (1974, 1976, 1979) procedures were           gen".
                     followed. A block digestor was used be-              Hobbie's nitrogen analyses consisted of
                     tween 1975 and sometime in 1977, when it         various pre-treatments of a sample fol-
                     was replaced by an autoclave. Since 1984         lowed by analysis as nitrite. The nitrite
                     the methods for phosphorus analyses have         was analyzed as an azo dye produced by
                     been described in detail in appendices in        sulphanilamide plus N-(l-napthyl)-

                        Appendices                                                                              207
                        ethylenediamine. This diazotization tech-      were automated using Technicon
                        nique was adapted for sea water by             Autoanalyzer equipment and EPA meth-
                        Bendschneider and Robinson (1952), and         ods. Cadmium reduction followed by ni-
                        it is described in full in Strickland and      trite analysis was the method they chose
                        Parsons (1968), which is the reference cited   for nitrate nitrogen determinations. They
                        by Hobbie in his reports. The nitrate was      cited EPA (1974) as their reference. Like
                        analyzed as nitrite following reduction in a   Davis et al., they also used the indophenol
                        copper-cadmium column (Morris and Riley        method for ammonia, and they cited EPA
                        1963). Ammonia also was analyzed as            (1974) as the reference for the method.
                        nitrite after oxidation of the sample with     Their total dissolved nitrogen analyses
                        alkaline hypochlorite, a method developed      were by automated Kjeldahl methods (EPA
                        by Richards and YJetch (1961). It really       1974). Total nitrogen was not measured.
                        gives ammonia plus amino acids,                    For a brief period (January-June 1975)
                        (Strickland and Parsons 1968), although        the ICMR nitrate analyses were made
                        the error is small, since amino acids are      using the brucine colorimetric method,
                        usually much less abundant than ammo-          which is based on the formation ofa colored
                        nia. Finally, the TN and TFN analyses          complex between nitrate and brucine sul-
                        were carried out using oxidation by strong     fate in a 13 N sulfuric acid solution at a
                        ultraviolet (UV) light to convert organic      temperature of 1000C (EPA 1974). How-
                        forms to a mixture of nitrate and nitrite      ever, since July 1975 the ICMR samples
                        (Armstrong et al. 1966; Strickland and         have been analyzed by the cadmium re-
                        Parsons 1968).                                 duction method, which was automated in
                            Davis et al. (1978) indicated that they    mid-1985.
                        used the UV spectrophotometric method             From 1975 through 1979 the ICMR
                        (APHA 1971) for nitrate determinations.        ammonia analyses were made using an
                        They analyzed ammonium nitrogen by the         Orion Ammonia Probe (D. Kornegay, per-
                        indophenol method, often referred to as the    sonal communication). Unfortunately, this
                        Solorzano (1969) method. Scheiner (1976)       ion-selective electrode was not very sensi-
                        modified the method slightly and Davis et      tive. It could not detect concentrations
                        al. cited this paper as their reference. In    below 0.1 mg ammonia N/liter (7.14 uM),
                        the indophenol method samples are treated      so that most of the normal range in ammo-
                        with sodium hypochlorite and phenol in an      nia levels in the estuary was missed. Be-
                        alkaline citrate medium. Sodium                ginning in 1980, the indophenol method
                        nitroprusside is used as a catalyst, and the   was adopted (Solorzano 1969), and it has
                        blue indophenol color formed with ammo-        been used continuously since then, al-
                        nia is measured spectrophotometrically         though minor modifications have been
                        (Parsons et al. 1984). Kjeldahl digestions     made at various times. Details of the
                        (EPA 1976) were used for the total nitro-      procedure from 1984 onward, including
                        gen and total dissolved nitrogen analyses.     the switch to the automated procedure in
                        This is one of the oldest and most widely-     1985, are given in the annual reports.
                        used methods for TN and TDN. Organic              Kjeldahl digestions were used for the
                        matter is converted to ammonia by heat-        ICMR total and total dissolved nitrogen
                        ing with sulphuric acid, and the ammonia       analyses beginning in January 1975. Be-
                        determined spectrophotornetrically by one      tween 1975 and the end of 1979, a block
                        of the methods given above.                    digester was used and the ammonia pro-
                           All of the nitrogen analyses performed      duced in the reaction was measured by
                        during the study by Kuenzler et al. (1979)     means of the same Orion ammonia probe

                     208                                                                             Appendices
                     used for the ammonia analyses. Beginning         from 1975 through 1980, although no de-
                     in 1980, the ammonia was determined by           tails are certain for that time period. Since
                     the indophenol blue method, modified             1980, this has been the method, with slight
                     slightly at various times. When the analy-       modifications, mostly involvingthe method
                     ses were automated in 1985, a combined           of extraction (e.g., grinding or no grinding
                     nitrogen-phosphorus digestion reagent            of filter pads), and the time allowed for
                     came into use. (Stanley 1987). The ammo-         extraction before the readings were made.
                     nia produced by this digestion was ana-          The chlorophyll data from part of 1985 are
                     lyzed by the indophenol method.                  suspect because of a problem involving
                                                                      unequal dispersion ofthe pigment in tubes
                          ChlorophyU a: Essentially the same          following centrifugation to sediment the
                     method has been used for chlorophyll a           glass fiber filter fragments. It seems that
                     analyses in all four of the Pamlico studies.     mostofthe pigment was collecting near the
                     Hobbie (1974) gave the following outline of      bottom of the tube, so that when the sample
                     the method: "Water samples were returned         was decanted into the spectrophotometer
                     to the laboratory ... and a part of the          cell, erroneously low readings were ob-
                     sample filtered through Gelman A glass           tained. This problem was corrected in
                     fiber filters for later chlorophyll analysis     -early 1986.
                     (filters were frozen)... Chlorophyll a was
                     measured by grinding the filters, extract-           Phytoplankton CeU Density and
                     ing with 90% acetone, and estimating the         Wet Weight Biomass: There have been
                     pigment           spectrophotometrically         two major studies of phytoplankton spe-
                     (Strickland and Parsons 1968). The spec-         cies, numbers, and biomass in the Pamlico.
                     trophotometric results were corrected for        The first was by Hobbie (1971) for the time
                     phaeophyton (Strickland and Parsons              period August 1966 through April 1968.
                     1968)" (Hobbie 1974, page 12). It is impor-      Two series of stations were sampled; one
                     tant to note that all the chlorophyll results    series from August 1966 to August 1967
                     from the other three studies were also           and the other from March 1967 to Febru-
                     corrected for phaeophyton.                       ary 1968. These were the same stations
                          Davis etal. (1978) filtered their samples   sampled for nutrients and hydrographic
                     within 12 hours of collection (filter type not   parameters during these time periods
                     given), and the filters were stored frozen in    (Hobbie 1970a, 1970b). The first series
                     a dessicator. Analyses of chlorophyll were       was sampled to examine the effects of the
                     made within 30 days of sample collection.        effluent from the phosphate slime (mining
                     They cited Strickland and Parsons (1972)         waste) pond located close to South Creek.
                     as the reference for the procedure they          When the effect could not be found, the
                     used. Kuenzler et al. (1979) also froze the      sampling was expanded to include most of
                     filter pads (Whatman GF/C) and analyzed          the estuary (Hobbie 1971).
                     for chlorophyll a by means of the acetone            Phytoplankton in the samples were
                     extraction-spectrophotometric method, fol-       identified and counted by the Utermohl
                     lowing the procedure given in Lorenzen           technique (Utermohl 1958). Briefly, the
                     (1967).                                          organisms were preserved in a Lugol's type
                          ICMR analyses ofchlorophyll a, like all     solution, settled into asmall countingcham-
                     the others described above, were made by         ber, the excess water removed, and the
                     measuring the extinction of an acetone           organisms counted with an inverted micro-
                     extract of the pigment. The method prob-         scope. Details are given in Hobbie's report.
                     ably followed Strickland and Parsons (1972)      The. most important advantage of this

                        Appendices                                                                                209
                        method is that it enables counting of the       identified and counted by D. Daniel. The
                        flagellates and nannoplankton as well as        membrane filtration method was used to
                        less fragile, larger forms (Hobbie 1971).       concentrate the Lugol's preserved algae
                            The second Pamlico phytoplankton            prior to counting at 40OX magnification
                        study, sponsored by North Carolina Phos-        (see Stanley and Daniel 1985a for details).
                        phate Corporation, was made during the          This method of concentrating the algae is
                        period April 1982 through December 1985         more rigorous than the Utermohl settling
                        (Stanley 1983, 1984a; Stanley and Daniel        method usedbyHobbie in the earlierstudy,
                        1985a, 1985b, 1986). The objective was to       but it apparently did not destroy the fragile
                        collect baseline data for future impact as-     flagellates and nannoplankton, so that
                        sessment of increased phosphate mining          results from the two studies are compa-
                        in the area. There was a concern that           rable.
                        higher nutrient loads could trigger nui-           In both of these phytoplankton studies,
                        sance blooms of algae in the Pamlico like       the algal biomass was calculated. Vol-
                        those that had become common by this            umes of representative individuals of each
                        time in the Chowan River and the Neuse          species were estimated by means of geo-
                        River. Samples were collected approxi-          metric formulae. These volumes were
                        mately every other week from stations in        multiplied by the species cell densities and
                        the river and in South Creek, a tributary       summed to give the total wet weight bio-
                        near the mining sites. The River stations       mass (ug/liter) for each sample. A specific
                        were the same ones used for the Texasgulf       gravity of unity was assumed (i.e., 1 ming
                        nutrient and hydrography study.                 = 1 ing wet mass) (Hobbie 1971; Stanley
                            Phytoplankton in the samples were           and Daniel 1985a).

                       210                                                                                Appendices

                       Appendix 4.4.
                       Review of methods for analyzing water quality time series data

                           The problem of testing water quality           However, if the type of change is not known,
                       monitoringdata fortrend intime has received        a two-tailed test should be used. It should be
                       increasing attention during the last decade,       stressed that, when possible, the one-tailed
                       primarily fortwo reasons (Hirsch et al. 1982).     alternative should be chosen.
                       First, there is interest in the question of           In order to apply trend detection tech-
                       changingwater quality arising from environ-        niques, there can be only one data point for
                       mental concern and activity. State and Fed-        each time unit. This data preparation prob-
                       eral legislation has resulted in the expendi-      lem arises when numerous observations are
                       ture of large sums of public and private           located in the same time unit, yet one value is
                       money for the purpose of water quality im-         needed to represent that discrete time unit.
                       provement, and there is naturally interest in      Means or median values may be used as a
                       evaluating the consequences of these expen-        measure of central tendency to represent the
                       ditures. Second, data sets covering a substan-     time period. When dealing with multiple
                       tial number of years are becoming increas-         data sources, an important consideration is
                       ingly common because of the establishment          whether the data are mutually compatible.
                       of monitoring programs in the early and mid-       Similar sampling designs, sampling devices,
                       1970's. Many of the trend analyses have            laboratory techniques and instruments may
                       involved data from national water quality          be a prerequisite to data merging; otherwise
                       networks such as the U.S. Geological Survey's      apparent trends may simply be an artifact of
                       NASQAN network (e.g., Smith et al. 1982).          a change in analytical methods. Under some
                           Montgomery and Reckhow (1984) out-             circumstances, the analyst may be able to
                       lined a four-step trend detection method: 1)       remove this analytical method effect from the
                       hypothesis formulation - statement of the          data series.
                       problem to be tested, 2) data preparation -            Once a hypothesis is formed and the data
                       selection of water quality variables and data,     are properly arranged (i.e., one datavalue per
                       3) exploratory data analysis, and 4) statistical   unit time) the data are ready to be explored
                       tests - tests for detecting trends.                and analyzed. The data analysis step will
                           Typically, the null hypothesis, H., is that    provide the necessary information to deter-
                       there is no change (notrend) in the population     mine which statistical test should be used to
                       of water quality values from which the data        test the null hypothesis. Of particular interest
                       were drawn. Consequently, the alternate            are characteristics of the data related to fre-
                       hypothesis, H1, may be either that a trend         quently invoked assumptions. Montgomery
                       does exist in the data (two-sided test) or that    and Reckhow (1984) and Smith et al. (1982)
                       a positive (or a negative) trend exists in the     discuss these assumptions and corrective
                       data (one-sided test). If it is known that a       measures to deal with assumption violations.
                       parameter either increased or decreased, a             Some of the techniques available for the
                       one-tail H, should be used. A one-tailed test      exploratory data analysis include a graph of
                       will maximize the probabilities of each out-       the data against time, the five number sum-
                       come by placing all the rejection region           mary graph which Tukey (1977) calls the
                       (alpha) at one tail ofthe outcome distribution.    box-and-whisker plot, Tukey smoothing, and

                             Appendices                                                                                             211
                             the autocorrelation function (McLeod et al.            any of these characteristics. The following
                             1983). Because no single method can clearly            discussion, taken from Letterunaier et al.
                             portray everything there is to learn about the         (1982), describes these common features of
                             data, it is advisable to use a number of               water quality data which must be recognized
                             exploratory techniques.                                before statistical methods can be selected.
                                 Hypothesis testing, the final step for trend           1. Seasonality: Most water quality vari-
                             detection, consists of the following steps, as         ables are affected directly or indirectly by
                             summarized by Smith et al. (1982):                     seasonal climatic changes. For instance,
                                 1. State the null hypothesis and back-             water temperature responds directly to air
                             ground assumptions for the test.                       temperature, although there is usually some
                                 2. Calculate an appropriate test statistic         lag which depends on the rate of heat transfer
                             from the data.                                         into and out of the ground and water. Water
                                 3. Interpret the value of the statistic in         temperature affects both the saturation con-
                             light of the known probability distribution of         centration of dissolved oxygen and the rates
                             the statistic.                                         of oxygen consumption and production by
                                 4. If the value of the test statistic is within    plants and animals in the water column and
                             preselected limits on the distribution, accept         sediments. Nutrient concentrations reflect
                             the null hypothesis; or,                               both levels of biological activity and fresh-
                                 5. If the value ofthe test statistic is outside    water inflow to the estuary, both of which in
                             the preselected limits, the null hypothesis            turn may have large seasonal variability.
                             cannot be accepted and a "statistically sig-           Most trend analysis techniques require that
                             nificant trend" is claimed.                            some procedure be employed to remove sea-
                                 The limits are calculated from a                   sonality. Montgomery and Reckhow (1984)
                             preselected probability - typically denoted by         reviewed some of these procedures.
                             the Greek letter alpha - such that the probabil-           2. Nonnormal probability distributions:
                             ity that the test statistic would fall outside the     Most water quality variables are positively
                             limits is (alpha) if the null hypothesis and all       skewed, since they cannot be negative, but
                             background assumptions were true. A typi-              may occasionally take on large positive val-
                             cal value selected for alpha is 0.1. Then one          ues. Examples of variables from the Pamlico
                             may say that a trend is, or is not, statistically      data set exhibiting this characteristic include
                             significant at the 10% level. That is, in 90%          nutrients and chlorophyll a. On the other
                             of the cases, one will correctly say there is no       hand, some variables have small ranges and
                             trend when such is true. One may also report           often are nearly symetric, and if seasonal
                             test results by a probability value (denote p).        variations are removed, may be nearly nor-
                             This is the probability that the test statistic        mally distributed. Examples include tem-
                             would depart from its expectation by at least          perature, dissolved oxygen, and pH.
                             the observed amount, under the null hypoth-                Most parametric statistical tests require
                             esis.                                                  that the data come from a population that is
                                 Most water quality data exhibit certain            normally distributed. A combination of in-
                             characteristics which can strongly influence           tuitive knowledge, graphical methods, and
                             the choice of an appropriate statistical trend         statistical tests should be used to determine
                             test. Thus it is very important that the data be       whether or not to use parametric tests, or
                             examined to determine whether they exhibit             nonparametric tests, which do not require a

                       212                                                                                Appendices
                       normal distribution of the parameter. Graphi-      tion" (Montgomery and Reckhow 1984).
                       cal techniques, involving visual compari-          Positive correlation between samples arises
                       sons, can be used to provide qualitative infor-    because fluctuations from the mean tend to
                       mation on the form of the underlying distri-       continue for a period that is usually long
                       bution. For larger samples (n>50), the             compared to the sampling interval. Such
                       Kolmogorow-Smirnov test (Sokal and Rohl f          variations are, from a statistical standpoint,
                       1981) can be used to test statistically the        "noise", and may obscure underlying trends.
                       assumption of normality. This test, it should      Persistence is usually not a major issue when
                       be noted, determines only whether the data         monthly sampling frequencies are used; for
                       exhibit significant deviations from normality      highersampling frequencies, such asbiweekly
                       and not whether they are normal (i.e., sup-        or weekly, it becomes increasingly impor-
                       ports the alternative hypothesis and not the       tant.     Various tests for detecting
                       null hypothesis) (Montgomery and Reckhow           autocorrelation are discussed in Montgom-
                       1984).                                             ery and Reckhow (1984), Kenkel (1975), and
                           3. Missing or nonuniformly sampleddata:        Sen (1978,1979).
                       Because of foul weather, equipment break-              5. Streamflow interaction: Some water
                       down, analytical errors, and changing ideas        quality variables display strong concentra-
                       as to appropriate sampling strategies, long-       tion gradients between freshwater and sea-
                       term time series are likely to have missing        water. For example, nitrate nitrogen is often
                       data. There may be long periods when no            100-fold or more concentrated in rivers than
                       samples were taken, and the intervals be-          in in the ocean. Consequently, in a low-
                       tween sampling dates are hardly ever uni-          salinity estuary like the Pamlico Riverwhere
                       form over a long period of time. Regardless        there is a strong riverine influence, the con-
                       of the cause, most traditional time series         centration of nitrate depends largely on Tar
                       techniques, which assume equal sample in-          River flow, especially in the upper half of the
                       tervals, are not appropriate to water quality      estuary where most of the mixing occurs.
                       data. Techniques exist to deal with a few              6. Censored data: Censored data are
                       isolated data gaps (Lettenmaier 1976;              those observations reported as being "less
                       D'Astous and Hipel 1979) by estimating             than" or "greater than" some specific value.
                       values for the missing data. However,ifthere       Examples include concentrations of nitrogen
                       are a lot of missing values, or one or more        and phosphorus which fall below the limits of
                       long gaps exist, the effect of data interpola-     detection (LD) of the analytical procedures.
                       tion on the identification of the stochastic       Where "less than LD" observations arise in
                       process and the ultimate trend testing become      the Pamlico data set, the LD values are used
                       very problematic (Hirsch and Slack 1984).          in the trend tests. This causes the distribution
                           4. Persistence: Water quality measure-         of the data to deviate even farther from
                       ments are not, in general, independent, but        normality, and so parametric tests become
                       are instead positively correlated (i.e., small     less exact. However, provided that the LD
                       values tend to be followed by small values         does not change over the period of record,
                       and large by large), and the correlation usu-      nonparametric tests such as the one used in
                       ally increases as the sampling interval de-        this study (see below), may be used with no
                       creases. This phenomenon is also sometimes         difficulty (Hirsch and Slack 1984).
                       termed "autocorrelation" or "serial coffela-           Statistical tests used for trend analyses

                           Appendices                                                                                          213
                           fall under one of two categories: 1) classical,      tions are present and not removed.
                           or parametric or 2) distribution-free, or non-           Another common parametric test for trend
                           parametric (Bradley 1968). Classical tests,          is based on linear regression of the variable of
                           such as those used in regression, require the        interest against time. The null hypothesis is
                           estimation of one or more parameters (for            that the variable and time are uncorrelated,
                           example, the slope of the regression line)           and the background assumptions are that the
                           based on the observed values of the variable         data are normal, independent, and identically
                           and the distribution of the test statistic under     distributed in time. If the slope of the regres-
                           the null hypothesis follows from an assump-          sion equation is found to be statistically sig-
                           tion about the underlying probability distri-        nificant, a trend is claimed. Unfortunately,
                           bution of the random variable.                       several of the assumptions underlying the
                               Distribution-free, or nonparametric, tests       derivation of the necessary probability distri-
                           typically ignore the magnitudes of the the           bution to test for significance are violated by
                           data in favor of the relative values or ranks of     natural data. In general, water quality data
                           the data. The major advantage of distribu-           have seasonality, are skewed, and serially
                           tion-free tests is that the underlying probabil-     correlated. These features contradict the
                           ity distribution of the random variable is           assumptions of stationarity, normality, and
                           immaterial. In fact, any strictly increasing         independence of the random variable (the
                           monotonic transformation - such as taking            water-quality variable) required for comput-
                           logarithms - changes the values of the data,         ing the probability distribution of the test
                           but does not affect the relative rankings.           statistic in the regression test for trend. The
                           However, because the magnitudes are ig-              seasonality inflates thevariance used inthe t-
                           nored, the test provides only a yes-or-no, not       tests, the skewness increases the standard
                           a how-much, answer.                                  error in the estimated slope, and the serial
                               The pros and cons of several parametric          correlation raises the actual alpha level rela-
                           and nonparametric tests for trend are dis-           tive to the selected alpha level. Any one of
                           cussed by Montgomery and Reckhow (1984),             these defects may be sufficient to render the
                           Hirsch and Slack(1984), Lettenmaier(1976),           test invalid, especially since the amount by
                           and Montgomery and Loftis (1987). Mont-              which they are present - and therefore, the
                           gomery and Loftis (1987) found that one of           amount by which the test is being distorted -
                           the most widely-used parametric tests, the t-        cannot be known.
                           test, is robust (i.e., is not appreciably affected       The same or similar objections can be
                           by a violation of a given underlying assump-         raised against virtually every test for trend
                           tion) for non-normal distributions if the dis-       when applied to almost any water-quality
                           tributions have the same shape (either symetric      variable. Attempts have been made to alter
                           or skewed) and sample sizes are equal. The           (transform) the data to remove or reduce the
                           Nest is also robust for unequal variances if         undesirable features. To remove seasonality,
                           the sample sizes are equal. The West appears         one might fit a sine curve to the data (Steele
                           not to be robust when 1) samples come from           et al. 1974) and use the deviations from the
                           two distributions ofdifferent shape, 2) samples      curve as the random variable to be tested. But
                           have unequal variances and unequal sample            with the exception of a few variables such as
                           sizes, 3) serial dependence in observations is       water temperature, there is little reason to
                           present, or 4) seasonal changes in concentra-        believe that the form of seasonality is a pure

                        214                                                                                    Appendices

                        sine curve. The extent to which the cure
                        works is largely unknowable. To eliminate
                        skewness, one might use the logarithms of the
                        data. Again, the extent to which this is proper
                        is only a guess. Compensating for serial
                        correlation is at best an art. Trying to do all
                        three is extremely difficult, if not impossible.
                        What is needed is a test that is largely unaf-
                        fected by the three above-mentioned charac-
                        teristics of the data. That is, the distribution
                        of the test statistic is influenced little by these
                        three characteristics of the data.

                          Appendices                                                                                     215
                          Appendix 4.5.
                          The Seasonal Kendall Trend test for water qulalty data

                             The distribution-free test which serves as     identical. A complete specification of the
                          the basis for trend testing in this study is      Seasonal Kendall test is given below. Its
                          Kendall's Tau (Kendall 1975). The null            derivation is given by Hirsch et al. (1982).
                          hypothesis for this test is that the random           When all assumptions for the regression
                          variable is independent of time. The only         test are met, the regression test is the most
                          necessary background assumption is that the       powerful test for linear trend (Kendall and
                          random variable is independent and identi-        Stuart 1968). The Seasonal Kendall test is
                          cally distributed (with any distribution). In     almost as powerful, based on a series of tests
                          this test, all possible pairs of data values are  using generated random numbers (Hirsch et
                          compared; if the later value (in time) is         al. 1982). When skewness and seasonality
                          higher, a plus is scored; if the later value is   were introduced into the experiments, the
                          lower, a minus is scored. If there is no trend    Seasonal Kendall test performed better than
                          in the data, the odds are 50-50 that a value is   the test based on linear regression; and when
                          higher (or lower) than one of its predecessors.   serial correlation was introduced, it's effect
                          In the absence of a trend, the number ofpluses    on the Seasonal Kendall test was no more
                          should be about the same as the number'of         severe than it's effect on linear regression.
                          minuses. If however, there are many more              In addition to indicating whether a trend
                          pluses than minuses, the values later in the      exists, it may be desirable to estimate the
                          series are more frequently higher than those      trend rate, or slope. Hirsch et al. (1982)
                          earlier in the series, and so an uptrend is       defined the Seasonal Kendall Slope Estima-
                          likely. Similarly, if there are many more         tor to be the median of the differences (ex-
                          minuses than pluses, a downtrend is likely.       pressed as slopes) of the ordered pairs of data
                             As discussed above, the one common             values that are compared in the Seasonal
                          pattern to water-quality variables is that they   Kendall test. Instead of recording a plus or
                          have a period of one year (other periodicities    minus for each comparison, one simply
                          may exist). Comparing, for example, a Janu-       records the difference divided by the number
                          ary value with a May value does not contrib-      of years seperating the data points. The
                          ute any information about the existence of a      median of these differences is taken to be the
                             trend, if aseasonal cycle of a 1-yearperiod    change per year due to the trend. A math-
                          exists. Thus, Hirsch et al. (1982) defined the    ematical description of the Seasonal Kendall
                          Seasonal Kendall test to be the Kendall's Tau     Test is given inAppendix B, page 32 inSmith
                          test restricted to those pairs of data which are  et al. (1982).
                          multiples of 12 months apart. Since compari-
                          sons are made only between data from the the
                          same month of the year, the problem of sea-
                          sonality is avoided. The random variables
                          may be nonidentically distributed, provided
                          that the distributions 12 months apart are

                                                                                         U.S. G.P.D.:1992-313-153:60516

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