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Strategic Assessment of Near Coastal Waters Susceptibility of East Coast Estuaries to Nutrient Discharges: Passamaquoddy Bay to Chesapeake Bay SUMMARYREPORT ME NH ,,VT NY MA 0 RI PA NJ 2....................................... VA NOAA/EPA Team on Near Coastal Waters TD June 1989 427 .07 S8 1989 National Estuarine Inventory The National Estuarine Inventory (NEI) is a series of related activities of the Strategic Assessment Branch (SAB), Office of Oceanography and Marine Assessment (OMA), National Oceanic and Atmospheric Admini- stration, (NOAA), to develop a national estuarine data base and assessment capability. The NEI was initiated in June 1983 as part of NOANs program of strategic assessments of the Nation's coastal and oceanic resources. The cornerstone of the NEI is the National Estuarine Inventory Data Atlas. Volume 1, completed in November .1985, identifies 92 of the most important estuaries and subestuaries of the contiguous USA. The atlas presents information through maps and tables on physical and hydrologic characteristics of each estuary, and specifies a commonly derived spatial unit for all estuaries, the estuarine drainage area (EDA), for which data are compiled (see inside back cover for a sample map). These estuaries represent approximately 90 percent of the estuarine water surface area and 90 percent of the freshwater inflow to estuaries of the East Coast, West Coast, and Gulf of Mexico. The database and assessment capabilities underdevelopment are part of an evolving process. Estuariesare being added to the inventory, especially along the West Coast and in the Gulf of Mexico, and refinements are being made to the physical and hydrologic data presented in Volume 1. Estimates of additional estuarine attributes, such as volume by salinityzone, flushing rates, and length andcharacteristics of shoreline have been added to the data base. Other volumes in the NEI data atlas series are Volume 2, Land Use Characteristics; Volume 3, Coastal Wetlands, and Volume 4, Public Recreational Facilities in Coastal Areas. Information from these atlases and other NOAA projects is being incorporated into the NEI through a NOAA geographic information system. The other NOAA projects are the National Coastal Pollutant Discharge Inventory, the National Shellfish Register and related projects; and the Estuarine Living Marine Resources project. National Coastal Pollutant Discharge Inventory Program The National Coastal Pollutant Discharge Inventory (NCPDI) Program is a series of data base development and analytical activities within NOAA's Strategic Assessment Branch (SAB) that assess the sources, magnitude, and impact of pollutant discharges within the Nation's coastal and estuarine areas. The cornerstone of the program is a comprehensive data base and computational framework that has been developed over the last eight years. The data base contains pollutant loading estimates for all major categories of point, nonpoint, and riverine sources located in coastal counties, or the 200-mile Exclusive Economic Zone, that discharge to the estuarine, coastal, and oceanicwatersof the contiguous USA (excluding the Great Lakes). The NCPDI Program is part of NOANs program of strategic assessments of the Nation's coastal and oceanic regions. The pollutant discharge estimates in the NCPDI are made for the base year 1982, but can be considered to approximate pollutant discharge conditions during the period 1980-85. Estimates are made for 18 pollutants in nine major categories: 1) wastewater; 2) oxygen-demahding materials; 3) particulate material; 4) nutrients; 5) heavy metals; 6) petroleum hydrocarbons; 7) chlorinated hydrocarbons; 8) pathogens; and 9) sludges. The pollutant estimates can be aggregated by county, hydrologic cataloging unit, or estuarine drainage area. A series of projects is currently underway within the NCPDI Program to improve and refine the estimates for selected pollutant source categories and coastal areas. These improvements include: expanding the study area to include more inland areas within estuarine drainage basins, updating the base year to 1987; using improved methods to estimate discharge, and adding a number of toxic pollutants to the inventory. In addition, projects are being undertaken to assess the impact of management practices on nonpoint source pollutant discharges and to develop computer applications that allow a user to better access and query the data base. Strategic Assessment of Near Coastal Waters Susceptibility of East Coast Estuaries to Nutrient Discharges: Passamaquoddy Bay to Chesapeake Bay SUMMARY REPORT NOAA/EPA Team on Near Coastal Waters June 1989 PLEASE NOTE Seventeen of the 23 estuarines in this report were included in a similar NOAAIEPA report, Strategic Assessment of Near Coastal Waters, Northeast Case Study, Chaper3, publishedin July 1988. Theyhave been repeated in this report for two reasons. First, for some estuaries there have been revisions to the nutrient discharge estimates, dissolved concentration potential values, ordischarge estimates necessary to change estimated nutrient concentration. Second, the set of estuaries in this report coincide with those in the Northeast section of NOAA's National Estuarine Inventory with one exception, Massachusetts Bay has replaced Boston Bay. Heather Quinn John Paul Tolson, C. John Klein, S. Paul Orlando, Charles Alexander College of Marine Studies Strategic Assessment Branch University of Delaware Ocean Assessments Division Newark, Delaware Office of Oceanography and Marine Assessment National Ocean Service National Oceanic and Atmospheric Administration Rockville, Maryland pro"Zty 01 coc bibrazy 115 7) Funding forthis project has been provided, in part, bythe U.S. Environmental Protection Agency, Office of Marine A and Estuarine Protection, through a cooperative agreement with the University of Delaware, College of Marine '4 Studies (CX814816-01). LA ro ck@ r1r- - 6 r'4' U . S . DEPARTMENT OF COMMERCE NOAA ol COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON , SC 29405-2413 CONTENTS Page Introduction ....................................... ................................................................... Background .......................................................................................................... Nutrient Sources and Loads ................................................................................. 2 Susceptibility to Pollution ...................................................................................... 3 Nutrient Status: Concentration, Classification, and N/P Ratio ............................. 6 Comparisons Among Estuaries ............................................................................ 9 Concluding Comments ......................................................................................... 10 References ........................................................................................................... 12 One-page Summaries of Susceptibility and Pollutant Status .................................... .1 4@ Introduction clude the nutrient loads (chiefly nitrogen and phosphorusy andphysical and hydrologic charac- This report summarizes estimates of the relative teristics that affect nutrient distribution and con- susceptibility and status of twenty-three estuaries centration. on the East Coast from Maine through Virginia with respect to nutrient-related pollution (figure 1). Towards Assessing Eutrophication Potential. It is the third report in a series being developed to Estimates of nutrient discharges and calculations assist the U.S. Envii ronmental Protection Agency of pollution susceptibility and nutrient concentra- implement its Near Coastal Waters and National tion may indicate the potential for eutrophication Estuary Programs. It follows a case study for within an estuary. This report presents estimates estuaries inthe northeast (NOAA/EPA, 1988) and of annual loads of nitrogen and phosphorus enter- a similar assessment for estuaries in the Gulf of ing each estuary in the region along with each Mexico (NOAAIEPA, 1989). The information in estuary's f lushi ng/dilution characteristics as based this report is intended to increase understanding upon flushing time and estuarine volume. From of coastal environmental problems and to serve these estimates average nutrient concentrations as a screening tool for coastal resource decision- are predicted for each estuary. These data may making. provide a relative indication of which estuaries are more likely to experience high nutrient levels and, The initial NOAA/EPA (1988) report includes therefore, which may have greater potential for a background information on eutrophication, addi- eutrophication problem. However, the degree to tional information on the dissolved concentration which eutrophic conditions occur in an estuary is potential of estuaries, and detailed information on influenced by additional factors that affect nutrient nutrient sources, discharge estimation methods, concentration which are not specifically quanti- and nutrient loads. The reader is referred to fied here. These factors include nutrient recycling NOAA/EPA (1988) for these discussions which as well as temporal changes -in loading (e.g. are abbreviated or omitted here. reduced agricultural runoff) and in hydrologic char- acteristics (e.g. fluctuation in freshwater inflow Two additional reports are being prepared forthe and periodic stratification) within each estuary. estuaries along the West Coast and estuaries alongthe East Coastfrom North Carolinathrough it is importantto. note that assessments made in Florida. These reports arebeing developed pri- this and other reports in the series are based on marily on the basis of data compiled in NOAA's estimated estuarine characteristics and nutrient National Estuarine Inventory (NEI) and National loadings. Hence, they do not reflect actual estu- Coastal Pollutant Discharge Inventory (NCPDI) arine measurements of nutrient,concentration or Program. documented symptoms of 'eutrophication. Stan- dardized and quantitative long-term records of A one-page summary is included for each of the total nutrient discharges and concentrations in twenty-three estuaries in the East Coast region USA estuaries do not exist. Therefore, assess- from Passamaquoddy Bay through Chesapeake ments of relative susceptibility to nutrient-related Bay. Each summary contains information on pollution and estimated status of nutrient concen- significant physical and hydrologic features, esti- trations provide water quality and resource man- mations of nutrient loading, pollution susceptibil- agers with some initial insight into current and ity, and nutrient concentrations, along with a potential eutrophication problems on a regional narrative to assist the reader in interpreting the and national scale. The characterization of actual data. eutrophication problems, or symptoms, in the estuaries is the next step in the process of under- Background standing the effects of estuarine, nutrient-related pollution. Eutrophication. Eutrophication is an over-abun- Organizing the Data by Estuary. Nutrient dis- --darice-, of nutrients (from natural or.man-made charge5 areresli mated for each estuary by estuar- sources) which may induce massive algal blooms ine drainage area (EDA). The EDA isthe land and and, due to subsequent algal decay, may result in water component of an entire watershed that the emission of noxious odors, depletion of dis- most directly aff ects the estuary. The EDA gener- solved oxygen in the water, and mass mortality of ally corresponds to the U.S. Geological Survey finfish and shellfish, among other problems. (USGS) hydrologic cataloging unit(s) that con- Important factors influencing eutrophication in- tains the head of tide and the seaward estuarine Passamaquoddy Bay Englishman Bay ME Narraguagus Bay Blue Hill Bay Penobscot Bay Muscongus Bay /N H Sheepscot Bay VT Casco Bay Saco Bay Great Bay Merrimack River ............ i@A NY Massachusetts Bay M R I .............................................C Cape Cod Bay PA Buzzards Bay Narragansett Bay NJ ............................................ Long Island Sound MD Gardiners Bay Great South Bay D VA Hudson River/Raritan Bay Barnegat Bay Delaware Bay Chincoteague Bay Chesapeake Bay Figure 1. Estuarine Drainage Areas. boundary. The EDAs are illustrated in detail in ing, feedlots, and milk processing. Primarysources NOAA's National Estuarine Inventory Data Atlas of nitrogen are from urea, feces, and other organic of Physical and Hydrologic Characteristics (1985). matter. Phosphorus sources include synthetic EDAs may fall completely within, or extend be- laundry detergent and water treatment chemi- yond, coastal counties. Estimates of nutrient cals. In this report, nutrient sources are divided loadings from point and nonpoint sources are into three broad categories: point, nonpoint, and made only for the coastal county portion of the upstream sources. EDA. Estimates of nutrient loadings from up- stream sources account for discharges from that Basis forEstimates. The estimates of nitrogen portion of the EDA outside the coastal county and discharge to estuaries in this region represent from the fluvial drainage area (FDA). TheFDAis total nitrogen (i.e. nitrogen from ammonia, nitrate, the land and water portion-of the entire watershed nitrite, and the organicf raction). Estimates of total upstream of the EDA. The percentage of EDA phosphorus include organic and inorganic forms land within the coastal counties is given for each of phosphorus. Data for nutrient loads are taken estuary in its one-page summary., from NOAA's National Coastal Pollutant Discharge Inventory (NCPDI), and are based on a combina- Nutrient Sources and Loads tion of monitored and estimated data, circa 1982. Methods used to estimate nutrient discharges for Nitrogen and phosphorus originate from natural the NCPDI data base are briefly summarized in and man-made sources. Some specific sources "Susceptibility and Concentration Status of North- of both nutrients include sediments, chemical east Estuaries to Nutrient Discharges" (NOAA1 fertilizers, -feces, and wastes f rorn meat process- EPA, A 988). The estimation methods are ex 2 plained in detail in the NCPDI Methods Docu- diagram in the one-page summary for each estu- ments (NOAA, 1987a-d) available from NOAA's ary. Incomplete coverage is due to land areas Strategic Assessment Branch (accuracy is dis- from which no runoff data are available (princi- cussed in NOAA/EPA, 1988, Appendix D). pally wetlands and barren lands) and, therefore, affects only nonpoint discharge estimates. (The Strearrif low and nutrient concentration data used distribution of land use shown in pie diagrams to calculate the NCPDI estimates of nutrient dis- ref lects only the coastal county portion of the EDA charge from upstream sources were obtained from which there is nutrient data; wetlands and from the USGS Water Resource Data Reports, barren lands are not included in land use dia- the USGS National Stream Quality Accounting grams.) Network (NASQUAN), and other USGS and state watermonitoring programs (NOAA, 1987c). Where Upstream Sources. Upstream sources include strearnflow and/or concentration data were un- input from all riverine sources with an average available, nutrient discharge was estimated using annual flow in excess of 1,000 cubic feet per data from nearby streams with similar flows and second (cfs). The upstream category accounts land use characteristics, or nutrient discharge for pollutant loads to the estuary that originate was prorated using drainage area information f romthose portions of the EDAoutside the coastal (NOAA, 1987c). counties and from the remainder of the fluvial portion of the drainage area. In the East Coast Point Sources. Point sources are those waste- region from Passamaquoddy Bay through the water treatment plants (WWTPs) and industrial Chesapeake Bay, estimates are made for 20 facilities that are land-based and discharge !U:L- upstream sources. Ler& to surface water within a coastal county' portion of the EDA through a pipe or similar Limitations of Estimates. The estimates pre- conveyance on a regular basis. In this East Coast sented do not account for all possible sources of region, there-are 300 major and 477 minorpublicly nutrient inpuLto the -estuary. -- Estimates- are not owned wastewater treatment plants (POTWs). A available for nutrient input from ocean influx, majorwastewatertreatment plantdischarges over groundwater inflow, bottom sediments, wetlands, 1 million gallons of treated water per day. The barren lands, and direct atmospheric deposition NCPDI estimates that 1,924 billion gallons of to -the iQstuarine -surface. . ;In some cases,-..the treated wastewater per year,are discharged to nutrient contributions from these sources may be surface water from POTWs in coastal counties of substantial (e.g. Jaworski, 1981; Moshiri et al., Maine through Virginia. There are 205 major and 1981; Jones and Lee, 1981). 1,941 rninorindustrialfacilities. A major industrial facility discharges more than 0.5 million gallons of Further, the NCPDI estimates for point and non- process water per day to surface waters. Indus- point sources represent "end of pipe" and "edge of trial facilities are estimated to discharge 565 bil- field" loadings. They do not take into account lion gallons of process water per year to surface transport phenomena and thus portray a very waters in coastal counties in the region. conservative, or high, estimate of the pollutant loads reaching the estuary from these sources. Nonpoint Sources. Nonpoint discharge is the Nevertheless, the NCPDI estimates do reflect the transport of dissolved and particulate materials to addition of nutrients from several important an- surface waters within the coastal county portion of thropogenic sources, and are valuable in evaluat- the EDA via surface runoff from precipitation. ing the relative contributions of different sources. Nonpoint discharges are subdivided into four categories: agriculture, forest, urban, and other Susceptibilty to Pollution (nonurban). Urban discharges represent nutrient input from urban areas with populations greater Susceptibility. An estuary's susceptibility to than 2,500. Discharges from combined sewer pollution is defined as its relative ability to concen- overflows are included in estimates of nutrient trate dissolved and particulate pollutants. Pollut- loads fr6m urban runoff. Throughout.the coastal 'antsin,estuades mvither,.dissolved in the water zone of the region there are 247 urban areas. or attached to particles in the water column or on Other (nonurban) sources include rangeland and the bottom. In general, nutrients occur in dis- pasture. The extent of data coverage for nonpoint solved form and toxic substances occur in particu- discharges within the coastal county portion of late form. Susceptibility is based upon the physi- each EDA is reported in the note following the pie cal and hydrologic characteristics of the estuary. 3 Estuaries that are most susceptible to pollution distributionof freshwaterin an estuary. Assuming are those which have poor ability to dilute orf lush a -uniform pollutant loading rate, the DCP is a dissolved substances, and are likely to trap sedi- function of flushing time and dilution as expressed ment and any associated toxic substances. by: Susceptibility is quantified by two parameters: DCP = L (VI. / i fj (1 / Vtj dissolved concentration potential (DCP) and par- where: IL = loading rate ticle retention efficiency (PRE). The DCP esti- mates the relative ability of an estuary to concen- Vfw @ volume of freshwater in the trate dissolved substances (total phosphorus and estuary nitrogen in this study). The PRE estimates the ifw @ rate of freshwater inflow relative ability of an estuary to retain suspended V. = total volume of the estuary particles and attached pollutants (chiefly toxic materials). This paper focuses on the DCP and its To allow comparison of the DCP between estuar- role in the concentration of dissolved nitrogen and ies, an equal pollutant load (10,000 tons/yr) is phosphorus in estuaries. Although PRE values assumed for all estuaries when calculating the are reported in this paper, discussion of the PRE DCP. Average annual conditions are used for is abbreviated, as this parameter will be dis- freshwater inflow and estuarine volumes. The cussed at length in a separate report on toxic volume of freshwater in the estuary is determined pollutants. by estimating and summing the freshwater frac- tion of the tidal fresh, mixing, and seawater por- A susceptibility classification scheme relating the tions of the estuary, as depicted in NOAA's Na DCP and PREwas developedto provide a relative tional Estuarine Inventory Data Atlas of Physical ranking of estuaries in terms of susceptibility to and Hydrologic Characteristics (1985). The esti- 'pollution (both dissolved and particulate pollut- mated freshwater fractions of USA estuaries-are ants). This classification scheme was applied to recorded in Klein and.Orlando (1989@_ estimates for 82 USA estuaries which are identi- tied in NOAA's NEI (including those in this report) High, medium, and low DCP classes are based (Klein et al., 1988). Figure 2 illustrates the relative upon order-of -magnitude differences in DCP val- -standing of the 82 estuaries in the classification ues. The range of values for low DCP is 0.01 to 0. 1 scheme and highlights susceptibility estimates for milligrams/liter (mg/1), for medium DCP is 0.1 to the 23 estuaries in the study area. 1.0 mg/l, and for high DCP is 1.0 to 10.0 mg/l. This order-of-magnitude classification scheme, used Dissolved Concentration Potential (DCP). The -for comparison- is necessary-- because both.the DCP characterizes the effect of flushing and estu- variabilityof dis@harge overtime and the state-of- arine dilution on a load of a dissolved pollutant to the-art techniques used to estimate loads set an estuary, assuming average concentration limitations on accuracy. (For discussion of accu- throughout the estuary and steady-state condi- racy of discharge estimates see NOAA/EPA, 1988, tions. The DCP is a relative measure of overall Appendix D.) potential and does not reflect site-specific condi- tions within an estuary. A high DCP value sug- The DCP does not characterize all estuaries gests that an estuary is likely to retain or concen- equally well. For example, the method assumes trate a load of dissolved pollutant. A low DCP a vertically homogenous system. Reliability of the suggests that an estuary has significant dilution DCP increases with the degree of mixing that is ability (due to large estuarine volume) and/or exhibited in the estuary. The DCP is of limited flushing ability (due to rapid volume replacement). utility in estuaries-where salinity stratification persists for significant periods. Moreover, the The DCP is based upon the freshwater fraction DCP assumes a recognizable freshwater inflow method for predicting the concentration of a pol- component, as expressed in the resultant salinity lutant (Ketchum, 1955), as modified by Klein and regime, to infer pollutant distribution. Forsystems ---,OrIando,(1 989)@ (Some additional information on like.CapqGod.Ray, Which, approaches the salinity the DCP is provided in Appendix E of NOAA/EPA, concentration of seawater, the DCP is less reli- 1988, and Klein et al., 1988). The distribution of able in predicting susceptibility to nutrient pollu- a dissolved conservative pollutant, designated as tion. nutrients in this case, is assumed to be affected by the physical forces of tide, freshwater inf low, and wind in the same manner that they affect the 4 Figure 2. Relative Susceptibility Classification for East Coast Estuaries (Maine through Virginia) LOW MEDIUM HIGH Estuary Abbreviaton 10 2 Passamaquoddy Bay PAS Englishman Bay ENG Narraguagus Bay NRS Blue Hill Bay BHB OCB Penobscot Bay PEB V Muscongus Bay MUS Sheepsoot Bay SHE 10 MAS Casoo, Say CAS 13UZ x Saoo Bay SAC GAR Great Bay GR71' 0 0 MUS Merrimack River MER CAS Massachusetts Bay MAS LIS NRS Cape Cod Bay CCB 0 46 0 1 PEB PAS NAR ENG 0 *GSB Buzzards Bay BUZ 0 * 0 0 40 CHI Narragansett Bay NAR - - - - - - - - - - - - - - - - - - - - . . . . . . . . &.11 . . . . . Long Island Sound LIS Gardiners Bay GAR CHE 0 Great South Bay GSB 0 DEL Hudson River/Raritan Bay H/R Bamegat Bay BNG Vill "0 V1.0 0 40 - .0 Delaware Bay DEL SHE 01 Op 13NG H/R 9 Chincoteague Bay CHI uj 0 Chesapeake Bay CHE .0 10 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --- - - GRT *49 10 -2 6MER 0 Ix Vil IV 10 00 -4 10 110-2 10-11 1 10 Dissolved Concentration Potential (mg/1) C volume of the estuary at mean sea level; I = total volume of freshwater W - -inflow- over an annual cycle; DCP based upon a loading of 1.0,000 tons/year. 5 Particle Retention Efficiency (PRE). The PRE The concentration of nitrogen or phosphorus is is an estimation of the relative ability of an estuary -predicted by'substituting the estimated nutrient to trap suspended particles along with pollutants loading rate of the estuary into the DCP formula adhering to those particles. Although some forms (replacing the 10,000 tons/yr pollutant loading of nitrogen and phosphorus can attach to par- rate used for the DCP calculation). Theestimated ticles, toxic substances are commonly associated nitrogen and phosphorus concentrations for all with suspended sediments. The PRE method estuaries identified in NOAA's National Estuarine assumes that the relative ability of an estuary to Inventory are plotted on figures 3a and 3b, re- trap sediment correlates to its ability to retain any spectively. Nutrient concentrations for estuaries associated toxic pollutant. The concept of PRE is for this region of the East Coast are highlighted based upon the empirical relationship between and both DCP and nutrient loads are shown on a sediment trapping efficiency and the capacity/ log-log scale. Nutrient concentration zones are inflow ratio, which was originally developed for bounded by the diagonal lines. The diagrams. man-made freshwater impoundments and subse- illustrate that certain systems can exhibit medium quently found to be loosely applicable to some es- to high concentrations even with low loadings if tuaries in the USA (Biggs and Howell, 1984). The the DCP is very high. The reverse is also true, in PRE is expressed by: that, medium to high concentrations may occur in estuaries with low DCPs if the loading is very high. PRE = C/I The concentrations used to designate high, where: C = volume (capacity) of the medium, and low concentration classes diff er for estuary nitrogen and phosphorus. For nitrogen, concen- I= annual freshwater inflow trations less than 0.1 milligramstliter (mg/1) are low, between 0.1 to 1.0 mg/I are medium, and The issue of toxic pollutants in estuaries will be greater than 1.0 mg/I are high. For phosphorus, dealt with in"a separate report. Therefore, further concentrations less than 0.01 -,mg/l,are:low,-be- discussion of sediment trapping efficiency is tween 0.01 and 0.1 mg/I are medium, and greater omitted here. PRE values are provided for each thanO.1 mg/larehigh. This classification scheme estuary to characterize overall susceptibility to is based upon observed estuarine characteristics both dissolved and particulate pollutant inputs as -at the different nutrient levels as reported for the expressed in figure 2. Chesapeake Environmental Ouality Classifica- tion Scheme (U.S. EPA, 1983). An estuarine Nutrient Status: Concentration, characteristic associated with low concentrations Uassification, and N/P Ratio is the maximum diversity of aquatic life -whereas high nutrient concentrations are associated with Nutdent Concentration and Classification. The high chlorophyll levels, low species diversity, and level of nutrient pollution is indicated by the esti- occasional red tides. mated concentrations of nitrogen and phospho- rus, a classification of those concentrations, and It is important to emphasize that the classification an indication of how a change in nutrient load scheme divides a continuum of concentrations. might affect the estuary's estimated nutrient con- Those estuaries whose nutrient concentrations centration classification. All predictions of nutri- are close to a class boundary are likely to exhibit ent concentration are based upon the estimates some characteristics of both classes. A minor of annual loads to the estuary. Estimates of change (<20%) in nutrient loadings may aff ect the nitrogen and phosphorus concentration do not concentration class of these estuaries, but actual take into account nutrient recycling, which may be estuarine conditions may not drastically improve substantial. Some studies suggest that nutrient or decline due to the small change in concentra- recycling may account for a greater percentage of tion actually made. Moreover, a change in nutri- the ambient nutrient concentration than the new ent loadings may not affect estuarine conditions load entering the system each year (e.g. Boynton precisely as predicted due to the discrepancy that ettil.-j,982@;Xemp etal., 1982)-. However, nutrient may existbetwe-en.-estimated nutrient concentra- recycling rates, aswell as peak and annual values tions and real concentratio ns. of primary productivity, apparently are a function of long-term loadingtothe estuary (Boynton et al., NIPRatio. The significance of the N/P ratio is that 1982; Kemp et al., 1982). phytoplanklon require nitrogen and phosphorus in the approximate proportion (atomic) of 16/1, 6 Figure 3a. Relative Status of East Coast Estuaries (Maine through Virginia) with Respect to Nitrogen 106 LOW MEDIUM HIGH ....... .... . ..... ............ -... ............ ...... Concentration (mgA) ................ ...... .. .... ................... ... .......... . ......... ...... .......... .. ......... - ............ ....... .................... . .......... .... High ................ I -1.1",".I... 1.. 1. 1 1 . I I I I I.. b...-.,--...,... E] GSB ............... ......... ............... ........ .... ........ ...... ............ . ... . . ... ... H/R .. .......... ....... .. . ............... - .. ........ .. ...... ..........-.... ...............I.....- ....... [3 MER ... . . ... ... ............ ....... .............-... ... .. .... .. ....... ...... ........ .... .... ................. ..... . ............. ........... 10 CHE ...... ....... ..... ........ Medium LIS . ..... ............ ........ . .............. . .......... ........ .... .. .......... .. .... ........... . ......... ...... .... BNG DEL ............. .. ....... . . .. ..... . ...... ............. CHE . . . . . . . . .......... ....... DEL ......... ... . . .... ...... . ...... GAR LIS . ... ...... ... 4 . .............. MAS -10 ............ `EB NAR SHE PEB ........... . . ............. NAR ........... M C Low . .......... 13NG :z ::: a ......... ... .......... . ......... . BHB ........ .. CA IM BUZ SAC 3 10 IM CAS GRT GAAR IM COB IM CHI CCB BUZ ENG GRT AS CHI MUS NRS ENG PAS 10 2 SAC SHE Refer to Figure 2 for key to S estuary abbreviations 10 10-2 10-1 1 10 Dissolved Concentration Potential (mg/1) Concentration (mg/1) LOW 12 MEDIUM E] HIGH Less than 0.1 Greater than 0.1 Greater than I and less than 1 7 Figure 3b. Relative Status of East Coast Estuaries (Maine through- Virginia) with Respect to Phosphorus LOW MEDEW---7 NGH 166- ....... .......... ........... .... ........ .............. .- .... ..... ..... . .. .......... ...... .......... .. ..... .. .... . ..... .............. ...........- . ......... .................... .. .................. .. ...... ....... .......... Concentration (mg/1) .... ...... ......... --- ............. .......... ....... . I...... .... .................... . .. .......... . ..... ................. .............. ................. ............ ..................... ... . . ........ .. .... . ............. . ........ ...... . .. :::: ...... ....................... High .... ............. .... . ... .......... ..........-...... ........... . . ........ ........................ ............ ...... .... ... ....... ............................. ...... ...........- ............ ......... .............. ........... ....... ....... E] CHE ................... . ......... ....... ....... ............. ................... ... .... ........ .... .. ..... . - ... DEL .......... .......... ... ...... ............ .......... ........... ....... .......... GSB ........... -- ......... ................. ........ ......................... ............ ........... ...... .... ................. ............ ....... .. .... .... - -.....- ....... . . .... .......... 5 - ---- ------ H/R . ......... ....... 10 .......... ..... 1...,....'','' 1: - * [3 MAS ...... .... ........... ... ... .... ....... ........ ............... ......... . ............ ................... . ................... . .................... .......................... 0 MER .................................... .... .............. . .......... .......... ............... .............. Medium ......... ..... ................- ..... ..... ........... ............ ................... .. . ..................... ......... ....... ... ............ ....CHE ..... . BNG .. ..................... ................. .. ............. @.I.I...., ..... .....-.......... . . .. ....... ... .......... BUZ ....... ... ...... ED CAS . ............... ...... 4 ... ...... .10 ........... .............. ........ .................. ... . .......... I...............,.............".....,. @........ ............ .- ............. ........................ LIS CGB . .......... ..... ...... ............. ............ ...... E3 CHI ..... . ..... GAR GRT ::I .......... ..................... ...... ..... ............... ................. LIS co NAR MEF1 ........ .......... ...... ............................. .. ................... PEB ........ . .... . .............. .................. ........- 3 10 PER Low .......... ..... ..... ... ........ 1.11, . ... ...... ................. . ..... ...-............ 1 -.1-1 .... ................. . . . . . ................... .......... ,BN@... "I M BHB ............. .................. SHE ...... ................. ........... Aq ........ ENG M MUS NRS ... .. ..... ..... ..................... CCB ............. ........... GFTr M PAS . .......... SAC ........ .. 2 10 SHE CHI Refer to Figure 2 for key to estuary abbreviations BHB ENG mus NRS 10 1 10 10-1 110 Dissolved Concentration Potential (rng/l) Concentration (mg/1) LOW MEDIUM HIGH Less than 0.01 Greater than 0.01 Greater than 0.1 and less than 0.1 8 respectively, for growth (Redfield, 1934, 1958). (NO;) and nitrite (NOO assimilation in phyto- -However, there is some indication that this ratio -plankton b NK+.(e.g.FaIkowskj,1983). Unfortu y 4 ' varies slightly with different algal species and that nately, studies of the different rates of chemical a range of N/P ratios from 10/1 to 20/1 better recycling and nutrient uptake are not common -describes nutrient requirements of algae (Boynton and tend to be site-specific. The impact of diff er- et al., 1982). Where the N/P ratio is 10/1 or less, ent nutrient ions on algal growth remains to be there may be insufficient nitrogen to balance all of fully explored. Hence the N/P ratio provided the available phosphorus. In such a situation, should be used as only a first approximation for nitrogen maybethe nutrientwhich limitsincreased evaluating nutrient dominance. plant production. In contrast, where the N/P ratio is 20/1 or greater, there may be insuff icient phos- jh:U*4A-*iw- Among Estuaries phorus to allow complete use of all available nitrogen, and phosphorus may be a limiting nutd- .,Comparisons of the estimated nutrient loads, ent. Where N/P ratios fall between 10/1 and 20/ DCPs, and nutrient concentrations between estu- 1, the limiting nutrient may be highly dependant aries in the region can be used to assess the uponthe speciet of phytoplankton present. There- extent to which these estuaries may be exped- fore, without site-specific information, a limiting encing nutrient-related problems under existing nutrient can not be determined with any assur- conditions and in the future. In addressing eutro- ance in the range of 10-20/1. In general, for the phication problems, the N/P ratio of the loading organisms that live in the different environments, gives a first estimate of which nutrient may be phosphorus is the limiting nutrient in freshwater more influencial in limiting phytoplankton produc- and nitrogen is the limiting nutrient in seawater; tion in the estuaries. estuaries represent atransition zone frornfresh to. seawater. It is important to emphasize that an For estuaries in the region, the dominant sources element@other than nitrogen or phosphorus may of nitrogen are WWTPs-and upstream sources. bethe production-limiting nutrient (e.g. silica,which The leading source of phosphorus.is WWTP dis- is required by diatoms in proportions of S/N/P= charge. Of -the twenty-three estuaries in the 20/16/1, Redfield, 1958) or a physical parameter region, ten estuaries are estimated to have rela- (e.g. light or temperature) may control primary tively poor dilution and/or flushing abilities (indi- production for all or part of the year. cated by high DCPs) (figure 2). Only two of these ten estuaries with high DCPs, Merrimack River The N/P ratio discussed in the one-page summa- and Great South Bay, are estimated to receive des is a highly speculative value based upon high loads of either, or both, nutrient(s). estimated nutrient loads; the ratio does not reflect : - . actual estuarine measurements. Estimated nutri- The predicted nutrient concentrations for the ent loads represent the weights of nitrogen and majority (fifteen) of the estuaries in the region are phosphorus from organic and inorganic mole- within the same concentration class forboth nutd- cules which enter the estuary each year. The N/ ents (figures 3a and 3b). (Recall, however, that P ratios were approximated by converting these concentrations used to designate high, medium, loads to the number of atoms (nitrogen or phos- and low concentration classes differ for nitrogen phorus load divided by the corresponding atomic and phosphorus.) Three estuaries are predicted weight) and dividing nitrogen by phosphorus to to have high concentrations of both nutrients and yield a ratio with the denominator, phosphorus, seven estuaries are estimated to have low con- equal to one. centrations of both nutrients. All seven estuaries with low predicted nitrogen and phosphorus con-. The estimated N/P ratios do not take into account centrations are located in Maine. recycling of nutrients within estuaries which may significantly affect the ambient nutrient concen- In the eight estuaries where nitrogen and phos- trations and thus the actual N/P ratios. Other phorus concentrations fall in diff erent classes, the factors that may influence the N/P ratio and the concentration of phosphorus is always predicted -.-limiting nutrient include the preferential uptake of to be---one.--class - -higher. than that of nitrogen. different ionic forms (e.g. nitrate, nitrite, ammo- Generally, in these estuaries, the contribution by nium), and varying rate of nutrient uptake by WWTPs to the overall nutrient load is quite different phytoplankton species. For example, significant a-r&! input from upstream sources-an some evidence supports the preferential uptake important contributor of nitrogen--@s virtually zero. of -ammonium .(NH4+) over nitrate - (NOO (Mc- Exceptions tothis are Delaware Bay and Chesap- Carthy, 1981) and the repression of both nitrate eake Bay where upstream sources are present. 9 In each of the two estuaries the phosphorus class from WWTPs is the leading source of phosphorus is high. (while the nitrogen class is medium) be- An each estuary.,All,three estuaries are estimated cause upstream sources, as well as WVVTPs, to have medium nitrogen concentrations, although contribute significant phosphorus loads. It is nitrogen loadings for the Delaware Bay and 1-importantto notethatforfive of the eight estuaries Chesapeake Bay are estimated to be high. The a minorincrease of nitrogen ordecrease of phos- Jeading source of:nitrogen in each estuary is phorus (<20% of the current estimated load) would discharge from upstream sources. The N/P ratio cause the predicted nutrient concentrations to be of the loadings suggests that Delaware Bay and in the same class. Massachusetts Bay may be nitrogen limited. If nitrogen is indeed the limiting nutrient, then reduc- Differences in loadings, DCPs, and nutrient con- tion of nitrogen loading would have the greatest centrations among the estuaries are important effect on algal growth in these two estuaries. The considerations in developing regional strategies N/P ratio for Chesapeake Bay does not indicate if .for the control of nutrient-related pollution. The either or both of the nutrient(s) are limiting to algal following discussion identifies and describes sig- growth. nificant differences among the region's estuaries that maybe cause for concern, andispresented Future Concerns. Most estuaries require a to stimulate further regionwide discussion. change in load greater than 20% of the present estimated load to change concentration class. Estuaries of Concern under Existing Condi- However, nine estuaries are exceptions to this tions. Estuaries which have high predicted con- and the concentration class may change for one -centrations of nitrogen and-ptiosphorus are the or both nutrients with a minor (<20%) change in most likely to be experiencing eutrophication nutrient loading(s). Of these nine estuaries, four problems. Three estuaries in the region are involve borderline medium-high concentration estimated to have bigh concentrations of both classes: . Chesapeake Bay,. Merrimack- River, nutrients: Merrimack River, Great South Bay, and Massachusetts Bay, and Narragansett Bay. Both Hudson River/Raritan Bay. (Predicted nutrient the nitrogen and phosphorus concentrations of concentration is a function of the estimated load- Chesapeake Bay are -likely to change--4he nitro- ing and the DCP). Both Merrimack River and gen level increasing from medium to high and the Great South Bay have high DCPs (poor dilution phosphorus concentration decreasing from high and/or flushing abilities) and generally high loads to medium--with a relatively minor (<20%) in- (the exception is the medium nitrogen load to crease in nitrogen and decrease in phosphorus Great South Bay). For Hudson River/Raritan Bay, from the present estimated loads. ForMerrimack which'has a medium DCP, high concentrations - River, Massachusetts Bay,,and Narragansett Bay, are predicted largely due to high loads. The N/P the concentration class of only one nutrient is ratio of the loadings suggests that Great South likely to be influenced with minor increases or Bay and Hudson River/Raritan Bay may be nitro- decreases from the present estimated loading. gen limited. Should this be the case, reduction of Specifically, with a minor reduction in nitrogen nitrogen loading would have the greatest effect on load, the nitrogen concentration class for Merri- algal growth in these estuaries. For these two mack River is likely to change (from high to estuaries, Great South Bay and Hudson River/ medium). The phosphorus concentration classes Raritan Bay, WWTPs are the leading source of are likely to change for Massachusetts Bay (from both nitrogen and phosphorus. The N/P ratio for high to medium) and Narragansett Bay (from Merrimack Riverdoes not indicate if eitherorboth medium to high) with a minor increase and de- of the nutrient(s) are limiting to algal growth. For crease, respectively, in phosphorus loads. Merrimack River, the leading source of nitrogen is discharge f rom upstream sources andthe leading Concluding Comments source of phosphorus is discharge from WWTPs. Inferred pollution susceptibility and nutrient con- Three additional estuaries are estimated to have centrations described above provide a first esti- high concentrations of phosphorus: Massachu- mate, of_the,@retabve.. status of one estuary com- setts Bay, Delaware Bay, and Chesapeake Bay. pared to anotherwith respectto potential nutrient- For these three estuaries, the high concentration related pollution problems and responsiveness to of phosphorus is due to high phosphorus loads. changes in nutrient loads. Such estimates maybe These high concentrations occurdespite medium useful for regional resource management and -Massachusetts; Bay and -Delaware Bay planning for-coastal,waters, particularly in the DCPs of and the low DCP of Chesapeake Bay. Discharge absence of standardized and quantitative long- 10 term measures of nutrient concentrations in estu- ades -and their state of eutrophism. However, an assessment of "actual" eutrophica- Aion problems and their characteristics can only be made by gathering site-specific information. A nationwide project starting in FY1990 is planned to collect such information. Site-specific iniorma- tion of eutrophication will be collected through site visits and the use of a standardized questionnaire completed by regional experts. Experts will in- clude both government and scientific personnel, who have knowledge of the absence or presence (and nature) of eutrophication problems in an estuary, or who can identify the existence or lack of site-specific data that could lead to determining the occurrence of a current or impending eutro- phication problem. For additional information on NOAA's program of strategic assessments contact: Strategic Assessment Branch Ocean Assessments Division Office of Oceanography and Marine Assessment National Ocean Service National Oceanic & Atmospheric Administration 11400 Rockville Pike Rockville, Maryland 20852 (301) 443-8921 References McCarthy, J..J. 1981. Uptake of Major Nutrients by Estuarine Plants. I[LB. J. Neilson and L. E. Biggs, R. B., and B. A. Howell. 1984. The Estuary Cronin (eds.), Estuaries and Nutrients. Humana as a, Sediment Trap: Alternate Approaches to Press, Clifton, New Jersey, p. 139-164. Eliminating Its Filtering Efficiency. JELV. S. Ken- nedy (ed.), The Estualy as a Filter. Academic Moshid, G. A., Aumen, N. G., and Crumpton, W. Press, New York, p. 107-129. G. 1981. Reversal of the Eutrophication Process: a Case Study. In-B. J. Neilson and L. E. Cronin Boynton, W. R., W. M. Kemp, and C. W. Keefe. (eds.), Estuaries and Nutrients. Humana Press, 1982. A Comparative Analysis of Nutrients and Clifton, New Jersey, p. 373-390. Other Factors Influencing Estuarine Phytoplank- ton Production. h2 V. S. Kennedy (ed.) Estuarine NOAA. 1985. National Estuarine Inventory Data Comparisons. Academic Press, New York, p. 69- Atlas: Physical and Hydrologic Characteristics. 90. Vol. 1. Strategic Assessment Branch, NOS/NOAA, Rockville, MD. Falkowski, P. G. 1983. Enzymology of Nitrogen Assimilation. in E. J. Carpernter, and D. G. NOAA. 1987a. The National Coastal Pollutant Capone (eds.), Nitrogen in the Marine Envirion- Discharge Inventory: Nonurban Runoff Methods ment. Academic Press, New York, Ch. 23, p. 839- Documents. Strategic Assessment Branch, NOS/ 868. NOAA, Rockville, MD. Jaworski, N. A. 1981. Sources of Nurtients and NOAA. 1987b. The National Coastal 'Pollutant the Scale of Eutrophication Problems in Estuar- Discharge Inventory: Point Source Methods ies. Ln-B. J. Neilson and L. E. Cronin (eds.), Document. Strategic Assessment Branch, NOS/ Estuaries and Nutrients. Humana Press, Clifton, NOAA, Rockville, MD. New Jersey, p. 183-110. NOAA. 1987c. The National Coastal Pollutant Jones, R. A. and Lee. G. F. 1981. The Signifi- Discharge Inventory: Upstream Sources Meth- cance of Dredging and Dredged Material as a ods Document. Strategic Assessment Branch, Source of Nitrogen and Phosphorus for Estuarine NOS/NOAA, Rockville, MD. Waters. ID_B. J. Neilson and L. E. Cronin (eds.), NOAA. 1987d. The National Coastal Pollutant Estuaries and Nutrients. Humana Press, Clifton, New Jersey, p. 517-530. Discharge Inventory: Urban Runoff Methods Documents. Strategic Assessment Branch, NOS/ Kemp, W. M., R. L. Wetzel, W. R. Boynton, C. F. NOAA, Rockville, MD. D'Elia, and L. C. Stevenson. 1982. Nitrogen Cycling NOAA/EPA. 1988. Strategic Assessment of Near and Estuarine Interfaces: Some Current Con- Coastal Waters, Northeast Case Study: Suscep- cepts and Research Direction. in V. S. Kennedy tibility and Concentration Status of Northeast (ed.) Estuarine Comparisons. Academic Press, Estuaries to Nutrient Discharges. Strategic As- New York, p. 209-230. sessment Branch, NOS/NOAA, Rockville, MD. Ketchum, B. H. 1955. Distribution of Coliform Chapter 3., 50 pp. Bacteria and Other Pollutants in Tidal Estuaries. NOAA/EPA (Quinn, H.A., Tolson, J. P., Klein, C. Sewage I ridustrial Wastes. Vol. 27, p. 1288-1296. J., Orlando, S. P., Alexander, C.). 1989. Strategic Klein, C. J., and S. P. Orlando. 1989. Estuarine Assessment of Near Coastal Waters: Suscepti- Pollution Susceptibility: An Approach to Classifi- bility and Status of Gulf of Mexico Estuaries to cation. Strategic Assessment Branch, NOS/ Nutrient Discharges. Summary Report, Strategic NOAA, Rockville, MD. Assessment Branch, NOS/NOAA, Rockville MD. 35pp. Klein, C.J., S.P. Orlando, C. Alexander, J. P. Redfield, A. C. 1934. On the Proportions of Or- Tolson, F. Shirzad, R. B. Biggs, and E. Zolper. ganic Derivatives in Sea Water-Their Relation to 1988. How Representative are the Estuaries Composition of the Plankton. James Johnstone Nominated for EPA's National Estuary Program, Memorial Volume. LiyqMDol University Press, .A Prefirr@nary Assessment. Strategic Assessment Branch, NOS/NOAA, Rockville, MD, 9pp. Liverpool, England, p. 176-192. 12 Redfield, A. C. 1958. The Biological Control of Chemical Factors in the Environment. American Scientist, Vol. 46, p. 205-221. U.S. EPA. 1983. Chesapeake Bay: A Framework for Action. EPA, Annapolis MID, Ch. 2, p. 33. 13 ii4atyss m e n t iii 10 MUM= ITY = Susceptibility of East Coast Estuaries to Nutrient Discharges Passamaquoddy Bay to Chesapeake Bay ESTUARY SUMMARIES Passamaquoddy Bay Cape Cod Bay Englishman Bay Buzzards Bay Narraguagus Bay Narragansett Bay Blue Hill Bay Gardiners Bay Penobscot Bay Long Island Sound Muscongus Bay Great South Bay Sheepscot Bay Hudson River/Raritan Bay Casco Bay Barnegat Bay Saco Bay Delaware Bay Great Bay Chincoteague Bay Merrimack River Chesapeake Bay Massachusetts Bay 1.01 Passamaquoddy Bay ME, NB PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 3.15 x 1011 El Urban Surface Area (sq. mi.) 157- Range & Other Nonurban Average Daily Inflow (cfs) 6,200 Estuarine Drainage Area (sq. mi.) %EDA Land within coastal counties 43 Nitrogen Point, Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 3,200 Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.27 (M) Agriculture Particle, Retention Efficiency, (C/1) 1.61 (H) Phosphorus Forest urban Other Nonurban NUTRIENT CHARACTERISTICS Upstream Sources Estimated Loadings (tons/year) Nitrogen Phosphorus Note: Data based on 90% of coastal county portion of EDA. Nutrient discharge estimates are unavailable for wetlands and Point 102 12 barren lands. Nonpoint 191 16 Upstream 0 0 INTERPRETATION Total 293 (L) 2 8 (L) Passamaquoddy Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential combined with To Chanae Conc. Class. the estimated nutrient loadings results in predicted Concentration Increase by Decrease by concentrations within the low range for both nitrogen mgA Class Load % Load % and phosphorus. In Passamaquoddy Bay, these low concentration classifications are not likely to be Nitrogen 0.008 (L) 3,411 1,164 NA NA influenced by minor increases (<20%) in nutrient Phosphorus 0.001 (L) 342 1,223 NA NA loadings. The N/P molecular ratio of the loading is 23, suggesting that phosphorus may be a limiting nutrient in Abbreviations: cfs, cubic feet per second; mg/l, milligrams per the estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration 'Office of Water U.S. Environmental Protection Agency 15 1.02 Englishman Bay ME PHYSICAL CHARACTERISTICS Land Use 0 Agriculture Dimensions Forest Volume (cu. ft.) 7.97 x 1010 Urban .Surface Area (sq. mi.) .76, El Range & Other Nonurban Average Daily Inflow (cfs) Estuarine Drainage Area (sq. mi.) 883 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 883 ..... Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.92 (M) Agriculture Particle- Retention 'Eff id ency@JCII) 1.58 (H) Phosphorus Forest El Urban Other Nonurban NUTRIENT CHARACTERISTICS . . . . . . . . .. . . . . .. Estimated Loadings (tons/year) Note: Data based on 90% of coastal county. portion of EPA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands a@d barren lands. Point 25 12 Nonpoint 125 10 Upstream 0 0 INTERPRETATION Total 150 (L) 2 2 (L) Englishman Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/yr) This dissolved concentration potential combined with To Change Cone, Class. the estimated nutrient loadings results in predicted Concentration Increase by Decrease by concentrations within the low range for both nitrogen mgA Class Load % Load % and phosphorus. In Englishman Bay, these low concentration classifications are not likely to 4 Nitrogen 0.014 (L) 937 625 NA NA influenced by minor increases (<20%) in nutrient Phosphorus 0.002 (L) 87 394 NA NA loadings. The N/P molecular ratio of the loading is i6, and does not strongly indicate the presence of a limiti,Rg Abbreviations: cfs, cubic feet per second; mg/l, milligrams per nutrient in the estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic.and Atmospheric Administration Office of Water.. U.S. Environmental Protection Agency 16 1.03 Narraguagus Bay ME PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 6.33 x 1010 urban Surface Area (sq. mi.) 70 E3 Range & Other Nonurban Average Daily Inflow (cfs) goo Estuarine Drainage Area (sq. mi.) 416 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 416 Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 1.54 (H) 0 Agriculture. -223 (H) - @Particle_Riaitention Efficiency.(C11)_ Phosphorus Forest Vrban Other Nonurban NUTRIENT CHARACTERISTICS .......... ............... @-"'@@_-Upstream. Sources Estimated Loadings (tons/year) Note: Data based on 87% of coastal county portion of ED.A. Nitrogen Phosphorus -Nutrient discharge estimates. are unavailable for wetlands and barren lands. Point 13 4 Nonpoint 91 7 Upstream 0 0 INTERPRETATION Total 104 (L) 11 (L) Narraguagus Bay is estimated to have a high Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential combined with To Change Conc. Class. the estimated nutrient loadings results in predicted Concentration Increase by Decrease by concentrations within the low range for both nitrogen mgA Class Load % Load % and phosphorus. In Narraguagus Bay, these low concentration classifications are not likely to be Nitrogen 0.016 (L) 545 524 NA NA influenced by minor increases (<20%) in nutrient Phosphorus 0.002 (L) 54 490 NA NA loadings. The N/P molecular ratio of the loading is 21, suggesting that phosphorus may be a limiting nutrient in Abbreviations: cfs, cubic feet per second; mg1l, milligrams per the estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Stidies Ocean Assessments Division University of Delaware (a Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of,'Watar U.S. Environmental Protection Agency 17 1.04 Blue Hill Bay ME PHYSICAL CHARACTERISTICS Land Use Agriculture DirnertWons Forest Volume (cu. ft.) 2.41 x 1011 El urban Surface Area (sq. mi.) 115- E2 Range & Other Nonurban Average Daily Inflow (cfs) 1,300 Estuarine Drainage Area (sq. mi.) 825 %EDA Land within coastal counties 97 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA N Wastewater Trt. Plants Total Drainage Area (sq. mi.) 825 M Industrial Facilities Politfilon Susceptlb .Ility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 1.03 (H) M Agriculture -eParticle"Ret6ftborY Efficie 5.88. - (H) 0 Forest Phosphorus El Urban Other Nonurban .......... NUTRIENT CHARACTERISTICS ............ Upstrearn.-Sources. Estimated Loadings (tons/year) Note: Data based on 92% of coastal county portion of EDA. Nitrogen Phosphorus @;,-@Nutrient discharge estimates are unavailable for wetlands ind barren lands. Point 48 22 Nonpoint 106 13 Upstream 0 0 INTERPRETATION Total 154 (L) 3 5 (L) Blue Hill Bay is estimated to have a high susceptibility for Predicted Concentration Status concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimated To Change Conc. Class. nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within the low range for both nitrogen and phosphorus. mg/I Class Load % Load % In Blue Hill Bay, these low concentration classifications are not likely to be influenced by minor increases (<20%) Nitrogen 0.016 (L) 817 530 NA NA in nutrient loadings. The N/P molecular ratio of the Phosphorus 0.004 (L) 62 177 NA NA loading is10, suggesting that nitrogen may be a limiting nutrient in the estuary. Abbreviations: cfs, cubic feet per second; mg/l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of- Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water U.S.Environmentai,Protection- Agency 18 1.05 Penobscot Bay ME PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 7.25 x 1011 Urban Surface Area (sq. mi.) 361 Range& Other Nonurban Average Daily Inflow (cfs) 16,100 Estuarine Drainage Area (sq. mi.) 3,160 Nitrogen %EDA Land within coastal counties 35 Point Sources Fluvial Drainage Area (sq. mi.) 6,250 Wastewater Trt. Plants Total Drainage Area (sq. mi.) 9,410 Pollution Susceptibility Industrial Facilities. Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.13 (M) Agriculture -@.@-Particio:.Retention-Efficiency,(C/I)--.i--:awv@, 1.43 (H) Phosphorus Forest El U rban NUTRIENT CHARACTERISTICS 0 Other Nonurban Upstream Sources Estimated Loadings 13 (tons/year) Note: Data based on 95% of coastal county portion of EDA. Nitrogen Phosphorus .-Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 173 58 Nonpoint 350 28 Upstream 7,285 685 INTERPRETATION Total 7,808 (M) 771 (M) Penobscot Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential combined with To Change Conc. Class, the estimated nutrient loadings results in predicted Concentration InQrease by Decrease by concentrations within the medium range for both mgA Class Load % Load % nitrogen and phosphorus. In Penobscot Bay, the medium phosphorus concentration classification may be Nitrogen 0.102 (M) 69,115 885 116 1 influenced by a minor reduction (<20%) in phosphorus Phosphorus 0.010 (M) 6,921 898 2 0 loading. The N/P molecular ratio of the loading is 22, suggesting that phosphorus may be a limiting nutrient in the estuary. Abbreviations: efs, cubic feet per second; mg/l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment 'National'Ocean Service Office-of Marine and Estuarine- Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 19 1.06 Muscongus Bay ME PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 8.55 x 1010 El Urban Surface Area (sq. mi.) 72 E2 Range & Other Nonurban Average Daily Inflow (cfs) 600' Estuarine Drainage Area (sq. mi.) 346 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 346 Pollution Susceptibility Industrial Facilities Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 2.25 (H) -4.52 (H) --'-Particle 'RetentJoh Efficiency .10/1) E Agriculture 0 Forest Phosphorus 13 Urban NUTRIENT CHARACTERISTICS Other Nonurban 'Upstream', Sources Estimated Loadings El (tons/year) Note: Data based on 89% of coastal county portion of EDA. -Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands arid barren lands. Point 13 11 Nonpoint 43 5 Upstream 0 0 INTERPRETATION Total 56 (L) 16 (L) Muscongus Bay is estimated to have a high susceptiUi@ty Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimated To Chanae Conc. Class. nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within the low range for both nitrogen and phosphorus. mgA Class Load % Load % In Muscongus Bay, these low concentration classifications are not likely to be influenced by min ,or Nitrogen 0.013 (L) 388 694 NA NA increases (<20%) in nutrient loadings. The K/P Phosphorus 0.004 (L) 28 178 NA NA molecular ratio of the loading is 8, suggesting that nitrogen may be a limiting nutrient in the estuary. Abbreviations: cis, cubic feet per second; mg/l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water 4J.-S. Environmental fl-tNectionAgency 20 1.07 Sheepscot Bay ME, NH PHYSICAL CHARACTERISTICS Land Use 0 Agriculture Dimensions Forest Volume (cu. ft.) 1.18 x 1011 El Urban Surface Area (sq. mi.) 103 Range & Other Nonurban Average Daily Inflow (cfs) 17,600 Es -tuarine Drainage Area (sq. mi.) 6,150 Nitrogen %EDA Land within coastal counties 16 Point Sources Fluvial Drainage Area (sq. mi.) 3,920 Wastewater Trt. Plants Total Drainage Area (sq. mi.) 10,070 Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.088 (L) M Agriculture Particle- Retention Efficiency-(C/1) 0.21 (M) 0 Forest Phosphorus El Urban Other Nonurban NUTRIENT CHARACTERISTICS Upstream, Sources Estimated Loadings 11 (tons/year) Note: Data based on 96% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetalnds and barren lands. Point 78 53 Nonpoint 472 44 Upstream 8,195 544 INTERPRETATION Total 8,745 (M) 641(M) Sheepscot Bay is estimated to have a low susceptibility Predicted Concentration Status for -concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimated To Change Conc, Class. nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within the low range for both nitrogen and phsophorus. mg/I Class Load % Load % In Sheepscot Bay, these low concentration classifications are not likely to be influenced by minor Nitrogen 0.077 (L) 2,619 30 NA NA increases (<20%) in nutrient loadings. The N/P Phosphorus 0.006 (L) 495 77 NA NA molecular ratio of the loading is 30, suggesting that phosphorus may be a limiting nutrient in the estuary. Abbreviations: cfs, cubic feet per second; mg1l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water U.S.'Environmental Protection Agency 21 1.08 Casco Bay ME PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.91 x 1011 0 Urban Surface Area (sq. mi.) 164.. E2 Range & Other Nonurban Average Daily Inflow (cfs) 2,100 Estuarine Drainage Area (sq. mi.) 1,159 Nitrogen . %EDA Land within coastal counties 84 Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 1,159 Industrial Facilities Pollution SuseVitiblIlty Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.61 (M) Agriculture ..'Particle Retention -Efficiency 2.89. (H) Phosphorus 0 Forest Durban NUTRIENT CHARACTERISTICS 0 Other Nonurban Sources ...Upstream. Loadings 0 (tons/year) .:Note: Data based on 97% of coastal county portion of EDA. -Nitrogen Phosphorus, Nutrient discharge estimates are unavailable for-wetlands and barren Point 744 408 Nonpoint 668 57 Upstream 0 0 INTERPRETATION Total 1, 412 (M) 465(M) Casco Bay is estimated to have a medium susceptibility Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential (DCP) combined with tfie To Change Conc. Class, estimated nitrogen loading results in a predicted Concentration Increase by Decrease by concentration within the low range for nitrogen. The mgA Class Load % Load % DCP combined with the estimated phosphorus loadih 6 results in a predicted concentration within the medium Nitrogen 0.086 (L) 227 16 NA NA range for phosphorus. In Casco Bay, the low nitrogen Phosphorus 0.028 (M) 1,174 253 301 65 concentration classification may be influenced by a mi&r increase (<20%) in nitrogen loading. The N/P molecufir Abbreviations: cfs, cubic feet per second; mg/l, milligrams per ratio of the loading is 7, suggesting that nitrogen may be liter; NA, not applicable; L, low; M, medium; H, high; C/l, a limiting nutrient in the estuary. volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office arid; EstuarinwProtection %P 0 National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 22 1.09 Saco Bay ME, NH PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.53 x 1010 Urban Surface Area (sq. mi.) 17 - E2 Range &- Other- Nonurban Average Daily Inflow (cfs) 3,600 Estuarine Drainage Area (sq. mi.) 1771 ..Nitrogen - %EDA Land within coastal counties 31 Point Sources Fluvial Drainage Area (sq. mi.) NA Total Drainage Area (sq. mi.) 1,771 Wastewater Trt. Plants Industrial Facilities PoIlLfilon SusceptiblIfty Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.45 (M) E Agriculture Particle Retention Efficiency-'-@Cff@@ 0.13 - - (M) 4 Phosphorus Forest Urban NUTRIENT CHARACTERISTICS' Other Nonurban Upstream., Sources Estimated Loadings (tons/year) ..Note: -Data based on 96% of coastal county portion of EDA. -Nitrogen- Phosphorus Nutrient discharge-estimates are unavailable for wetlands and barren lands. Point 187 117 Nonpoint 195 21 Upstream 875 55 INTERPRETATION Total 1,257 (M) 193(M) Saco Bay is estimated to have a medium susceptibility for Predicted Concentration Status concentrating dissolved substances. This dissolvdd (load in tons/year) concentration potential combined with the estimated To Change Conc. Class, nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within the low range for both nitrogen and phosphorus. mg/l Class Load % Load % In Saco Bay, the low phosphorus concentration classification may be influenced by a minor increase Nitrogen 0.057 (L) 965 77 NA NA (<20%) in phosphorus loading. The N/P molecular ratio Phosphorus 0.009 (L) 29 15 NA NA of the loading is 14, and does not strongly indicate the presence of a limiting nutrient in the estuary. Abbreviations: cfs, cubic feet per second; mg/l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water @@-IJ;S.-Envftomentai-Protectiort@-Agency 23 1 .10 Great Bay ME, NH PHYSICAL CHARACTERISTICS Land Use E Agriculture Dimensions Forest Volume (cu. ft.) 4.75 x 109 Urban Surface Area (sq. mi.) @,. 15 Average Daily Inflow (cfs) 2,000 E2 Range & Other,Nonurban Estuarine Drainage Area (sq. mi.) . %EDA Land within coastal counties 95 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 950 ............ Industrial Facilities .... ...... Pollution Susceptibility Conc Class Nonpoint Sources Dissolved 'Concentration Potential (mg/1) 1.54 (H) M Agriculture 'l-Particle Retention@Efficiency-(C A) 0.08 (L) 0 Forest Phosphorus El urban Other Nonurban NUTRIENT CHARACTERISTICS Upstream.. Sources- Estimated Loadings 13 (tons/year) -Note: Data based on-97% of coastal county portion of EDA. Nitrogen Phosphorus_ Nutrient discharge. estimates are unavailable for wetlands and barren lands. Point 242 161 Nonpoint 394 43 Upstream 0 0 INTERPRETATION Total 636 (L) 204(M) Great Bay is estimated to have a high susceptibility for Predicted Concentration Status concentrating dissolved substances. This dissolved (load in tons/year) concentration potential (DCP) combined with the To Change Conc. Class. estimated nitrogen loading results in a predicted Concentration Increase by Decrease by concentration within the low range for nitrogen. The' mgA Class Load % Load % DCP combined with the estimated phosphorus loading results in a predicted concentration within the medium Nitrogen 0.098 (L) 13 2 NA NA range for phosphorus. In Great Bay, the low nitrogen Phosphorus 0.031 (M) 445 218 139 68 concentration classification may be influenced by a minor increase (<20%) in nitrogen loading. The N/P molecuiar Abbreviations: cfs, cubic feet per second; mg/l, milligrams per ratio of the loading is 7, suggesting that nitrogen may'be liter; NA, not applicable; L, low; M, medium; H, high; C/l, a firniting nutrient in the estuary volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment -National Ocean'Service -@:@'Offidb-df@Wftfinw,,and@Estuarine, Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 24 1.11 Merrimack River NH, MA PHYSICAL CHARACTERISTICS Land Use 0 Agriculture Dimensions Forest .............. Volume (cu. ft.) 2.08 x 109 El Urban Surface Area (sq. mi.) 6 12 Range & Other Nonurban Average Daily Inflow (cfs) 8,400 Estuarine Drainage Area (sq. mi.) 2,300 -%EDA Land within coastal counties 30 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) 2,680 Wastewater Trt. Plants Total Drainage Area (sq. mi.) 4,980 Pollution Susceptibility Industrial Facilities Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 1.01 (H) Agriculture Particle, Retention Efficiency 0.01 (L) Phosphorus Forest Urban NUTRIENT CHARACTERISTICS Other Nonurban Upstream.. Sources El Estimated Loadings (tons/year) Note: Data based on 96% of coastal county portion of EQA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 1,343 813 Nonpoint 614 90 Upstream 8,154 722 INTERPRETATION Total 10,111 (H) 1,625 (H) Merrimack River has high susceptibility for concentrating Predicted Concentration Status dissolved substances. This dissolved concentrafio"n (load in tons/year) potential combined with the estimated nutrient loadings results in predicted concentrations within the high ran& To Change Conc. Class, for both nitrogen and phosphorus. In Merrimack Rive r, Concentration Increase by Decrease by the high nitrogen concentration classification may oe mgA Class Load % Load % influenced by a minor reduction (<20%) in nitrogeri loading. The N/P molecular ratio of the loading is 14, And Nitrogen 1.021 (H) NA NA 210 2 does not strongly indicate the presence -of a limiti-n"g Phosphorus 0. 164 (H) NA NA 635 39 nutrient in the estuary. Abbreviations: cfs, cubic feet per second; mg1l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; CA, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National.Ocean Service Office.of Marine and Estuarine Protection "Natlio'nalOceanic and Atmospheric Administration.-. 'VficeofWateT--- U.S. Environmental Protection Agency 25 1.12 Massachusetts Bay MA PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 7.85 x 1011 Urban Surface Area (sq. mi.) 364.. E3 Range & Other Nonurban Average Daily Inflow (cfs) 2,900 .Estuarine Drainage Area (sq. mi.) 1,202 %EDA Landwithin coastal counties 98 Mtrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Wastewater Trt. Plants Total Drainage Area (sq. mi.) 1,202 . . . . . . . . . . . . . . . . . Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.27 (M) Agriculture '-Particle:Retention Efficiency@(C 8.58 (H) Forest Phosphorus El Urban NUTRIENT CHARACTERISTICS 0 Other Nonurban Upstream Saurces Estimated Loadings 0 (tons/y.ear) Nitrogen Note: Data based on 96% of coastal county-portion of EDA. Phosphorus Nutrient discharge estimates are -unavailable for wetlands and barren lands. Point 6,181 3,845 Nonpoint 1,814 246 Upstream 0 0 INTERPRETATION Total 7,995 (M) 4,091 (H) Massachusetts Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential (DCP) combiridd To Change Conc. Class, with the estimated nitrogen loading results in a predicted Concentration Increase by Decrease by concentration within the medium range for nitrogen. The mgA Class Load % Load % DCP combined with the estimated phosphorus loading results in a predicted concentration within the high range Nitrogen 0.216 (M) 29,042 363 4,291 54 for phosphorus. In Massachusetts Bay, the high Phosphorus 0.110 (H) NA NA 387 9 phosphorus concentration classification may be influenced by a minor rediction (<20%) in phosphorus Abbreviations: cfs, cubic feet per second; mg1l, milligrams per loading. The N/P molecular ratio of the loading is 4 liter; NA, not applicable; L, low; M, medium; H, high; C/l, suggesting that nitrogen may be a limiting nutrient in the volume/inflow. estuary. Strategic Assessment Branch College of Marine Studies @Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection @zOffide oUWater' National Oc6arilt andAtmospheric Administration U.S. Environmental Protection Agency 26 1.13 Cape Cod Bay MA PHYSICAL CHARACTERISTICS Land Use E Agriculture Dimensions Forest Volume (cu. ft.) 1.18 x 1012 El Urban Surface -Area (sq. mi.). .548 [2 Range & Other@Nonurban Average Daily Inflow (cfs) 1,806 Estuarine Drainage Area (sq. mi.) 771 Nitrogen %EDA Land within coastal counties 100 Point Sources Fluvial Drainage Area (sq. mi.) NA -A-INS- Wastewater Trt. Plants Total Drainage Area (sq. mi.) 771 ........ .... Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources -Dissolved Concentration Potential (mg/1) 0.69 (M) Agriculture tParticle-ReWntion Efficiency (CA) 20.75 (H) Phosphorus Forest El urban NUTRIENT CHARACTERISTICS 0 Other Nonurban -Upstream -,Sources Estimated Loadings E3 (tons/year) -Note: Data based on 86% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates@dre unavailable for wetlands a'nd. barren lands. Poi nt 268 169 Nonpoint 109 18 Upstream 0 0 INTERPRETATION Total 377 (L) 187(M) Cape Cod Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential (DCP) combined To Chanae Conc. Class, with the estimated nitrogen loading results in a predicted Concentration Increase by Decrease by concentration within the low range for nitrogen. The mg/l Class Load % Load % DCP combined with the estimated phosphorus loading results in a predicted concentration within the mediurh Nitrogen 0.026 (L) 1,072 284 NA NA range for phosphorus. In Cape Cod Bay, these Phosphorus 0.013 (M) 1,262 675 42 22 concentration classifications are not likely to be influenced by minor changes (<20%) in nutrient Abbreviations: cfs, cubic feet per second; mg/l, milligrams per loadings. The N/P molecular ratio of the loading is 4, liter; NA, notapplicable; L, low; M, medium; H, high; CA, suggesting that nitrogen may be a limiting nutrient in too volume/inflow. estuary. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessme nt --Vl6onal OceanSorvice Office-of @Marine and -f-stuarine Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 27 1.14 Buzzards Bay MA PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 2.15 x 1011 El Urban Surface Area (sq. mi.) 228 E2 Range & Other Nonurban Average Daily Inflow (cfs) 1,200 Estuarine Drainage Area (sq. mi.) 576 %EDA Land within coastal counties 100 Nitrogen@ Point Sour rces Fluvial Drainage Area (sq. mi.) NA Total Drainage Area (sq. mi.) 576 Wastewater Trt. Plants . . . . . . . . . . ... ...... X X. .. .... Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 1.04 (H) Agriculture -Iie-gftrticle Retention Eff iciency,,(C/1@--@--&--ic@ 5.68 (H) Phosphorus Forest El urban NUTRIENT CHARACTERISTICS Other Nonurban Upstream -@Sources Estimated Loadings 0 (tons/year) Note: Data based on 93% of coastal county portion of EDA. Nitrogen Phosphorus_ Nutrient discharge estimates are. unavailable Jor wetlands and barren lands. Poi nt 306 193 Nonpoint 164 22 Upstream 0 0 INTERPRETATION Total 470 (L) 215 (M) Buzzards Bay is estimated to have a high susceptibility Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential (DCP) combined with the To Change Cone, Class, estimated nitrogen loading results in a predicted Concentration Increase by Decrease by concentration within the low range for nitrogen. The mgA Class Load % Load % DCP combined with the estimated phosphorus loading results in a predicted concentration within the medium Nitrogen 0.049 (L) 492 105 NA NA range for phosphorus. In Buzzards Bay, these Phosphorus 0.022 (M) 747 347 119 55 concentration classifications are not likely to be influenced by minor changes (<20%) in nutrient Abbreviations: cfs, cubic feet per second; mg/l, milligrams per loadings. The N/P molecular ratio of the loading is 5, liter; NA, not applicable; L, low; M, medium; H, high; C/l, suggesting that nitrogen may be a limiting nutrient in volume/inflow. estuary. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service 'Office'b!`Mafme and -Estuarine- Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 28 1.15 Narragansett Bay MA5 R1 PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.39 x 1011 El Urban Surface Area (sq.- mi.) .165 E2 Range & Other Nonurban Average Daily Inflow (cls) 3,200 Estuarine Drainage Area (sq. mi.) 1,330 . . .... Nitrogen %EDA Land within coastal counties 100 Point Sources Fluvial Drainage Area (sq. mi.) 451 Total Drainage Area (sq. mi.) 1,781 Wastewater Trt. Plants Industrial Facilities Pollution Susceptibility mg/I Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.52 (M) Agriculture Phosphorus Forest E]U rban Other Nonurban NUTRIENT CHARACTERISTICS Upstream -Sources Estimated Loadings 0 (tons/year) Note: Data based on 96% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates, are unavailable for wetlands di@d barren lands. Point 2,854 1,541 Nonpoint 1,717 235 Upstream 0 0 INTERPRETATION Total 4,571 (M) 1,776(H) Narragansett Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential combined with To Change Conc. Class. the estimated nutrient loadings results in predicteid Concentration Increase by Decrease by concentrations within the medium range for both mgA Class Load % Load % nitrogen and phsophorus. In Narragansett Bay, the medium phosphorus concentration classification may be Nitrogen 0.238 (M) 14,660 321 2,648 58 influenced by a minor increase (<20%) in phosphorus Phosphorus 0.092 (M) 147 8 1,584 89 loading. The N/P molecular ratio of the loading is 6, suggesting that nitrogen may be a limiting nutrient in tqq Abbreviations: cfs, cubic feet per second; mg1l, milligrams per estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and-Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water @[email protected],Environmentai-frotection-Agency 29 1.16 Gardiners Bay NY PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.11 x loll Urban Surface Area (sq. mi.) 197 Average Daily Inflow (cfs) 706 Range & Other Nonurban Estuarine Drainage Area (sq. mi.) 400 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Total Drainage Area (sq. mi.) 400 Wastewater Trt. Plants Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg1l) 1.77 (H) E Agriculture -Partic16"Rdtention -1Effici6ncy-(CfQ-- 5.03 (H) Phosphorus 0 Forest Urban NUTRIENT CHARACTERISTICS Other Nonurban .-Upstrearn, Sources Estimated Loadings El (tons/year) . Note: Data based on 95% of coastal county portion of EDA. Nitrogen, Phosphorus Nutrient discharge estimates are unavailable for wetlands abd barren lands. Point 643 407 Nonpoint 341 34 Upstream 0 0 INTERPRETATION Total 984 (L) 441(M) Gardiners Bay is estimated to have a high susceptibility Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimat'Od To Change Conc. Class. nutrient loadings results in predicted concentratiotis Concentration Increase by Decrease by within the medium range for both nitrogen and mgA Class Load % Load % phosphorus. In Gardiners Bay, these medium concentration classifications are not likely to be Nitrogen 0. 174 (M) 4,666 474 419 43 influenced by minor changes (<20%) in nutrient Phosphorus 0.078 (M) 124 28 385 87 loadings. The N/P molecular ratio of the loading is'-$, suggesting that nitrogen may be a limiting nutrient in the Abbreviations: cfs, cubic feet per second; mg/l, milligrams per estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic-arid'AtmospheticAdministration U.S. Environmental Protection Agency 30 1.17 Long Island Sound NY, CT, MA PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest ........... ......... . 12 El Urban Volume (cu. ft.) 2.19 x 10 Surface Area (sq. mi.) 1,281 E]Range & Other Nonurban Average Daily Inflow (cfs) 30,000 Estuarine Drainage Area (sq. mi.) 7,230 %EDA Land within coastal counties 49 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) 10,010 Total Drainage Area (sq. mi.) 17,240 Wastewater Trt. Plants Pollution Susceptibility Industrial Facilities Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.054 (L) Particle Retention Efficiency (C/1) 2.32 (H) Agriculture Phosphorus Forest El Urban NUTRIENT CHARACTERISTICS 13 Other Nonurban Upstream Sources Estimated Loadings 11 (tons/year) Note: Data based on 98% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 19,980 4,987 Nonpoint 5,532 630 Upstream 24,652 1,899 INTERPRETATION Total 50,164(H) 7,516 (H) Long Island Sound is estimated to have low susceptibility Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimated To Change Qonc. Class. nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within- the medium range for both nitrogen and mgA Class Load % Load % phosphorus. In Long Island Sound, these medium concentration classifications are not likely to be Nitrogen 0.271 (M) 135,021 269 31,645 63 influenced by minor changes (<20%) in the nutrient Phosphorus 0.041 (M) 11,003 146 5,664 75 loadings. The N/P molecular ratio of the loading is 15, and does not strongly indicate the presence of a limiting Abbreviations: cfs, cubic feet per second; mg/l, milligrams per nutrient in the estuary. liler; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies ..Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration U.S. Environmental Protection Agency 1.18 Great South Bay NY PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest 10 Urban Volume (cu. ft.) 3.73x 10 Surface Area (sq. mi.) 151 Average Daily Inflow (cfs) 700 Range & Other Nonurban Estuarine Drainage Area (sq. mi.) 845 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Total Drainage Area (sq. mi.) 845 Wastewater Trt. Plants Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 5.07 (H) Agriculture Particle Retention Efficiency (c/1) 1. 69 (H) Phosphorus Forest Urban NUTRIENT CHARACTERISTICS Other Nonurban Upstream Sources Estimated Loadings (tons/year) Note: Data based on 92% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 6,114 3,868 Nonpoint 1,990 284 Upstream 0 0 INTERPRETATION Total 8,104 (M) 4,152 (H) Great South Bay is estimated to have a high susceptibility Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimated To Change Conc. Class, nutrient loadings results in predicted concentrations Concentration Increase by Decrease by within the high range for both nitrogen and phosphorus mg/l Class Load % Load % In Great South Bay, these high concentration classifications are not likely to be influenced by minor Nitrogen 4.109 (H) NA NA 6,132 76 reductions (<20%) in nutrient loadings. The NIP Phosphorus 2.105 (H) NA NA 3,955 95 molecular ratio of the loading is 4, suggesting that nitrogen may be a limiting nutrient in the estuary. Abbreviations: cis, cubic feet per second; mg/l, milligrams per liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 32 1.19. Hudson River/Raritan Bay NY5 NJ, MA, CT PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.73 x 1011 .... El Urban Surface Area (sq. mi.) 298 Average Daily Inflow (cfs) 26,700 Range & Other Nonurban Estuarine Drainage Area (sq. mi.) 8,467 %EDA Land within coastal counties 79 Nitrogen Fluvial Drainage Area (sq. mi.) 8,037 Point Sources Total Drainage Area (sq. mi.) 16,504 wastewater Trt. Plants Pollution Susceptibility Industrial Facilities Conc Class Dissolved Concentration Potential (mg/1) 0.20 (M) Nonpoint Sources @@@Parficle Retention -Efficiency 0.20 (M) Agriculture Phosphorus Forest urban NUTRIENT CHARACTERISTICS E!2 Other Nonurban Upstream Sources Estimated Loadings (tons/year) Nitrogen Phosphor .us Note: Data based on 97%.of coastal county portion of EDA. Nutrient discharge estimates are unavailable for wetlands apd Point 34,526 20,688 barren lands. Nonpoint 13,161 1,162 Upstream 21,000 1,271 Total 68,687 (H) 23,121 (H) INTERPRETAT110N Predicted Concentration Status The Hudson River/Raritan Bay estuary is estimated to (load in tons/year) have a medium susceptibility for concentrating dissolved To Change Conc. Class, substances. This dissolved concentration potenUal Concentration IncreasQ by Decrease by combined with the estimated nutrient loadings results in mgA Class Load % Load % predicted concentrations within the high range for both nitrogen and phosphorus. In Hudson River/Raritan Bay, Nitrogen 1.374 (H) NA NA 18,687 27 these high concentration classifications are not likely to Phosphorus 0.462 (H) NA NA 18,121 78 be influenced by minor changes (<20%) in nutrient loadings. The N/P molecular ratio of the loading is 7, Abbreviations: cfs, cubic feet per second; mg/l, milligrams per suggesting that nitrogen may be a limiting nutrient in the liter; NA, not applicable; L, low; M, medium; H, high; C/l, estuary. volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water 33 1.20 Barnegat Bay NJ PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 1.34 x 1010 Urban Surface Area (sq. mi.) .102 E3 Range & Other Nonurban Average Daily Inflow (cfs) 2,300 Estuarine Drainage Area (sq. mi.) 1,350 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) NA Total Drainage Area (sq. mi.) 1,350 Wastewater Trt. Plants Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 1.36 (H) ,-,A-Particle Retention -Efficiency -(C/1). A.18 (M) Agriculture Phosphorus Forest El Urban E] Other Nonurban NUTRIENT CHARACTERISTICS Upstream Sources Estimated Loadings (tons/year) Note: Data based on 76% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 816 312 Nonpoint 1,212 179 Upstream 0 0 INTERPRETATION Total 2,028 (M)r 491(M) Barnegat Bay is estimated to have a high susceptibifity Predicted Concentration Status for concentrating dissolved substances. This dissolved (load in tons/year) concentration potential combined with the estimatdd To Change Conc. Class, nutrient loadings results in predicted concentratioRs Concentration Increase by Decrease by within -the the medium range for both nitrogen aad mgA Class Load % Load % phosphorus. In Barnegat Bay, these mediLiM concentration classifications are not likely to Nitrogen 0.276 (M) 5,325 263 1,293 64 influenced by minor changes (<20%) in nutrient Phosphorus 0.067 (M) 244 50 417 85 loadings. The N/P molecular ratio of the loading is suggesting that nitrogen may be a limiting nutrient in the Abbreviations: cfs, cubic feet per second; mg/l, milligrams per estuary. liter; NA, not applicable; L, low; M, medium; H, high; C/l, volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office'of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water U.`S.@Environmental 'Protection -Agency 34 1.21 Delaware Bay DE2 NJ, PA, MD PHYSICAL CHARACTERISTICS Land Use 0 Agriculture Dimensions Forest Volume (cu. ft.) 4.48x 10 11 El urban Surface Area (sq. mi.) 768 E2 Range & Other Nonurban Average Daily Inflow (cfs) 19,800, Estuarine Drainage Area (sq. mi.) 4,750 %EDA Land within coastal counties 79 Nitrogen Point Sources Fluvial Drainage Area (sq. mi.) 8,700 0 Wastewater Trt. Plants Total Drainage Area (sq. mi.) 13,450 Industrial Facilities Pollution Susceptibility Conc Class Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.14 (M) @i,@,vo-Rarticle; Retention Efficiency 0.72 (M) Agriculture Phosphorus 0 Forest El Urban N .UTRIENT CHARACTERISTICS 0 Other Nonurban Upstream Sources Estimated Loadings 11 (toni/year) Nitrogen Phosphorus Note: Data based on 85% of coastal county portion of EDA. Nutrient discharge estimates are unavailable for wetlands and barren lands. Poi nt 18,675 10,815 Nonpoint 4,224 596 Upstream 27,220 1,698 INTERPRETATION Total 50,119 (H) 13,109 (H) Delaware Bay is estimated to have a medium Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential (DCP) combined To Chanae Conc. Class. with the estimated nitrogen loading results in a predicted Concentration 113crease by Decrease by concentration within the medium range for nitrogen. -rfi6 mgA Class Load % Load % DCP combined with the estimated phosphorus load,i.66 results in a predicted concentration within the high range Nitrogen 0.702 (M) 21,310 43 42,976 86 for phosphorus. In Delaware Bay, these concentration Phosphorus 0.184 (H) NA NA 5,966 46 classifications are not likely to be influenced by minor changes (<20%) in nutrient loadings. The N/P molecu Abbreviations: ds, cubic feet per second; mg11, milligrams per ratio of the loading is 8, suggesting that nitrogen may'a liter; NA, not applicable; L, low; M, medium; H, high; C/l, a limiting nutrient in the estuary. volume/inflow. Strategic Assessment Branch College of Marine Studies Ocean -Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office of Water -0.-S.,Envkmrnentaf Protection-Agency 35 1.22 Chincoteague Bay MD, VA PHYSICAL CHARACTERISTICS Land Use 0 Agriculture Dimensions Forest Volume (cu. ft.) 2.25 x 1010 Urban Surface Area (sq. mi.) 137,-.- E3 Range & Other Nonurban Average Daily Inflow (cis) 400 Estuarine Drainage Area (sq. mi.) 300 %EDA Land within coastal counties 100 Nitrogen Point Sources Fluivial Drainage Area (sq. mi.) NA 0 Wastewater Trt. Plants Total Drainage Area (sq. mi.) 300 Polluition Susceptibility Industrial Facilities Conc Class Nonpoint Sources Dissolved,Concentration Potential,(mg/1) 3.08 (H) Agriculture -P fficIti-Retention, Efficiency 1.79 - (H) -a Phosphorus Forest El Urban NUTRIENT CHARACTERISTICS Adl@ 0 Other Nonurban Upstream Sources Estimated Loadings qr 11 (tons/year) @Note: Data based on 69%.of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge,estimates are unavailable for wetlands and barren lands. Point 110 62 Nonpoint 182 22 Upstream 0 0 INTERPRETATION Total -292 (L) 8 4 (L) Chincoteague Bay is estimated to have a high Predicted Concentration Status susceptibility for concentrating dissolved substances. (load in tons/year) This dissolved concentration potential (DCP) combined To Change Conc. Class, with the estimated nitrogen loading results in a predicted Concentratiol) Increase by Decrease by concentration within the low range for nitrogen. The mg/l Class Load % Load % DCP combined with the estimated phosphorus loading should result in a predicted concentration within the Nitrogen 0.090 (L) 33 11 NA NA medium range for phosphorus. In Chincoteague Bay, Phosphorus 0.026 (M) 241 287 52 61 the low nitrogen concentration classification may be influenced by a minor increase (<20%) in nitrogen Abbreviations: cfs, cubic feet per second; mg1l, milligrams per loading. The N/P molecular ratio of the loading is 8, liter; NA, not applicable; L, low; M, medium; H, high; C/l, suggesting that nitrogen may be a limiting nutrient in to volume/inflow. estuary. Strategic Assessment Branch College of Marine Studies -:0cean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and Estuarine Protection National Oceanic and Atmospheric Administration Office, of Water 'U.S. 'Environmi entail, Protection Agency 36 1.23 Chesapeake Bay VA, MD, DE, PA, DC PHYSICAL CHARACTERISTICS Land Use Agriculture Dimensions Forest Volume (cu. ft.) 2.59 x 1012 El urban Surface Area (sq. mi.) 3,830 Range & Other Nonurban Average Daily Inflow (cfs) 85,800 7 Estuarine Drainage Area (sq. mi.) 21,955 Nitrogen %EDA Land within coastal counties 80 Point Sources Fluvial Drainage Area (sq. mi.) 47,325 E Wastewater Trt. Plants Total Drainage Area (sq. mi.) 69,280 E Industrial Facilities Pollution SusceptiblItty Conc Class .... Nonpoint Sources Dissolved Concentration Potential (mg/1) 0.072 (L) M Agriculture Particle Retention PEfficiency-ICtl) 0.96 (M) EJ Forest Phosphorus El urban NUTRIENT CHARACTERISTICS 13 Other Nonurban Upstream Sources Estimated Loadings (tons/year) Note: Data based on 94% of coastal county portion of EDA. Nitrogen Phosphorus Nutrient discharge estimates are unavailable for wetlands and barren lands. Point 21,707 11,147 Nonpoint 10,973 1,433 Upstream 87,249 4,233 INTERPRETATION Total 119,929(H) 16,813 (H) Chesapeake Bay is estimated to have a low susceptibility for concentrating dissolved substances. This dissolved Predicted Concentration Status concentration potential (DCP) combined with the (load in tons/year) estimated nitrogen loading results in a predicted To Change Conc. Class. concentration within the medium range for nitrogen. The Concentration Increase by Decrease by DCP combined with the estimated phosphorus loading mgA Class Load % Load % should result in a predicted concentration within the high range for phosphorus. In Chesapeake Bay, the medium Nitrogen 0.863 (M) 18,960 16 106,040 88 nitrogen concentration classification may be influenced Phosphorus 0. 121 (H) NA NA 2,924 17 by minor increases(<20%) in nitrogen loading, and the high phosphorus concentration classification may be Abbreviations: cfs, cubic feet per second; mg/l, milligrams per influenced by minor reductions (<20%) in phosphorus liter; NA, not applicable; L, low; M, medium; H, high; C/l, loading. The N/P molecular ratio of the loading is 16, and volume/inflow. does not strongly indicate the presence of a limiting nutrient in the estuary. 0-- 0 Strategic Assessment Branch College of Marine Studies Ocean Assessments Division University of Delaware Office of Oceanography and Marine Assessment National Ocean Service Office of Marine and-Estuarine Protection National Oceanic and Atmospheric Administration Office of Water U.S. Environmental Protection Agency 37 National Estuarine Atlas 7@' Delaware Bay PHYSICAL AND HYDROLOGIC CHARACTERISTICS DE, NJ, PA, MD PH@_SICAL FRESHWATER INFLOW TIDAL DATA BUCKS 02030105 )02030104 P E N N S Y L V/A N I A 1@ A--- .1 M. 42 /MONTGOMERY N.. Y." .3 103 MERCER -M 0 N M 0 U I H A-- 02040105 239 117 1 02040203 I .F LANCAS E R Z M-1 L. Fl. 020 0201 --d -60'2 4 P ... @Y-. 0. A--- A-LW E-- DF I A W An F 02040202 oo;;-] 50306 1 BURLING 0.@ OCEAN ku 0204020@,_ NEW J %E R S E'Y LOUCESTE CAMDEN;@' -\ / ',% 02040301 02060002 1 1 CECIL NEW Y C Section CASTLE 02040102 I . Tide Gage 2040206 , R ATLANTIC F' 101 Flow Gage A A' Head of Tide r CUMBER LAN 7P M A R LA ND El Estuarine Drainage Area (EDA) CE. e_1 Tidal Fresh Zone ca@ wy @1 207 1 c M., 11.1k Mixing Zone N E 020 16000 4020 Seawater Zone T ATLANTIC ED 39'- A TI, Hydrolgi. Cataloging Unit Bnd.,V E3 County Boundary SUSSE X A' Salinity Zone Boundary - Low Variability Notts: 02060008 Salinity Zone Boundary - Moderate Variability One hundred percent of Estuarine Drainage Ar a is shown on map. Drainage Divide A Salinity Zone Boundary - High Variability represents portion of Estuarine Drainage Are: boundary not coinciding with U.S. OCEAN 0M Geok,gical Suniey cataloging unit boundary. 11DELAWAR R feremes: A11R,1982. Ambrose and Roesch. 1982. Buchanan, 1983. Delaware River Basin 02060010 Commissiori, 1980. Flippo. 1982. Hatchet and Harleman, 1981. James, at al., 1982. 0"9-: US, G%Y.%@ S- d P@y- ktjdj@ U@ New Jersey Department of Environmental Protection, 1978. Schaefer, of al.. 1982. 19. - I W,- - o - -@, `_ L. .. Simmons, 1967. Simmons and Carpenter, 1978. Thatcher and Harleman, 1978. U.S. - .'..=9@ u. 0 8 16 24 MILES Department of Commerce. 1983a. Voylik. et al., 1982. A u-S tic'm lu ;0 KILOMETERS1 1.21 v Non-iii 0-i S@11004A ')02@ Ao'ctil or co ..V' )I @-A (4i a I'm 4 -- 11 a 'TP-Ar s Of f ell 9 P-+ L . @ 3 6668 00002 0539