The URL can be used to link to this page

Lower Cape Fear River Program 2021 reportEnvironmental Assessment of the Lower Cape Fear River System, 2021 By Michael A. Mallin, Matthew R. McIver, Colleen N. Brown and James F. Merritt November 2022 CMS Report No. 22-02 Center for Marine Science University of North Carolina Wilmington Wilmington, N.C. 28409 1 Executive Summary Background – Multi-parameter water quality sampling for the Lower Cape Fear River Program (LCFRP) http://www.uncw.edu/cms/aelab/LCFRP/index.htm, has been ongoing since June 1995. Scientists from the University of North Carolina Wilmington’s (UNCW) Aquatic Ecology Laboratory perform the sampling effort. The LCFRP currently encompasses 32 water sampling stations throughout the lower Cape Fear, Black, and Northeast Cape Fear River watersheds (Table 1.1; Fig. 1.1). The LCFRP sampling program includes physical, chemical, and biological water quality measurements and analyses of the benthic and epibenthic macroinvertebrate communities, and has in the past included assessment of the fish communities. Principal conclusions of the UNCW researchers conducting these analyses are presented below, with emphasis on water quality of the period January - December 2021. The opinions expressed are those of UNCW scientists and do not necessarily reflect viewpoints of individual contributors to the Lower Cape Fear River Program. The mainstem lower Cape Fear River is a 6th order stream characterized by periodically turbid water containing moderate to high levels of inorganic nutrients. It is fed by two large 5th order blackwater rivers (the Black and Northeast Cape Fear Rivers – Fig. 1.1) that have low levels of turbidity, but highly colored water with less inorganic nutrient content than the mainstem. While nutrients are reasonably high in the river channels, major algal blooms are normally rare because light is attenuated by water color or turbidity, and flushing in the estuary is usually high (Ensign et al. 2004). During periods of low flow algal biomass as chlorophyll a increases in the Cape Fear River because lower flow causes settling of more solids and improves light conditions for algal growth. Periodically major algal blooms are seen in the tributary stream stations, some of which are impacted by point source discharges. Below some point sources, nutrient loading can be high and fecal coliform contamination occurs. Other stream stations drain blackwater swamps or agricultural areas (traditional agriculture and/or industrialized animal production), and some sites periodically show elevated pollutant loads or effects (Mallin et al. 2015). This region has been hit by hurricanes several times in the past three decades and such storms have a marked impact on water quality and organisms. GenX Issues - During the past four years there has been considerable controversy in the lower Cape Fear River watershed regarding a family of manufactured chemical compounds popularly known as GenX. To briefly summarize, DuPont constructed a facility known as Fayetteville Works near the river downstream of Fayetteville, where it manufactured fluoropolymers since 1971. DuPont manufactured a chemical called PFOA at Fayetteville Works beginning in 2001 and later stopped its manufacture due to health concerns surrounding this chemical. They then developed a substitute chemical called GenX, which they began manufacturing there, along with GenX’s parent compound, called HFPO-DA fluoride. Both compounds hydrolize in water to a third compound called HFPO-DA, CAS; the toxicity of this group of chemicals is unclear. Subsequently, DuPont spun-off a company called Chemours, which assumed plant operations in 2015. In the past few years researchers from US EPA, North Carolina State University, and the University of North Carolina Wilmington have found HFPO-DA 2 and related fluoroethers (which tend to be lumped under the blanket term GenX) in river water, river sediments, well water near the plant, in air samples, aquatic organism tissue, bird tissue, and in finished drinking water at the Wilmington water treatment facility, which obtains its water near Lock and Dam #1. Fayetteville Works says they have stopped the GenX discharge, and in 2019 built a thermal oxidizer to heat waste gases and reduce >99% of the chemicals from escaping; however these chemicals are still found in river water that enters the Cape Fear Public Utility Authority water treatment plant (which in 2022 had to increase its level of treatment in an effort to reduce these chemicals in Wilmington drinking water). Legal actions have been initiated against the company from a number of stakeholders to provide financial compensation for the pollution and for installation of pollution-reduction equipment. Sampling and analysis of GenX and related compounds is outside of the purview of the scientific staff of the Lower Cape Fear River Program and will not be discussed in this report. Summary of water quality data results from 2021 Year after year there is a dissolved oxygen sag in the main river channel that begins at Station DP below a paper mill discharge and near the Black River input, and persists into the mesohaline portion of the estuary. Mean oxygen levels are highest at the upper river stations NC11 and ANC and in the low-to-middle estuary at stations M35 to M18 (Fig. 1.1). Lowest mainstem mean DO levels normally occur at the river and upper estuary stations NAV, HB, BRR and M61. The Northeast Cape Fear and Black Rivers are classified as blackwater systems because of their tea colored water. The Northeast Cape Fear and Black Rivers generally have lower DO levels than the mainstem Cape Fear River. In 2021 GS (Goshen Swamp) was below standard 33% of occasions samples; SR 25% of the time, ANC (Angola Creek) and NCF6 (both on the Northeast Cape Fear River) were below standard on two sampling occasions. All of the other stream stations were below standard less than 10% of the time. Considering all sites sampled in 2021, we rated 3% as poor for dissolved oxygen, 16% as fair, and 81% as good. Annual mean turbidity levels for 2021 were lower than the long-term average at all stations. Highest mean riverine turbidities (11-12 NTU) were at NC11-DP (Fig. 1.1) with turbidities generally low in the middle to lower estuary. The estuarine stations only exceeded standard in February 2021. Turbidity was considerably lower in the Northeast Cape Fear River and Black River than in the mainstem river. Turbidity levels were low in the freshwater streams, with all streams rated as good for 2021. Suspended solids were generally low except at NC11 and AC, the upper river sites. Average chlorophyll a concentrations across most sites were low in 2021. The standard of 40 µg/L was not exceeded. There were several small blooms, mainly at GS and PB (Panther Branch). We note the highest chlorophyll a levels in the river and estuary typically occur late spring to late summer. Nuisance cyanobacterial blooms did not occur in the river and upper estuary in 2021. For the 2021 period UNCW rated 100% of the stations as good in terms of chlorophyll a. 3 Fecal bacteria counts in the estuary and at many of the stream stations were elevated in 2021. Sites with the highest counts in general were Goshen Swamp (GS), PB (Panther Branch), HAM (Hammond Creek), ROC (Rockfish Creek), NC403 (uppermost Northeast Cape Fear River site),LRC (Little Rockfish Creek, Angola Creek (ANC) and Sarecta (SAR). However, the main river and estuary sites were generally in good condition in 2021. For bacterial water quality overall, 16% of the sites rated as poor, 13% as fair, and 71% as good. In addition, according to our experimentally-derived key concentrations, excessive nitrate and phosphorus concentrations were problematic at a number of stations. Sites with high nutrient concentrations included point-source locations NC403, PB and ROC and non-point locations 6RC (Six Runs Creek) and GCO (Great Coharie Creek). A 20-year analysis of nutrient changes found that nitrate, total nitrogen and total phosphorus concentrations significantly increased in stream sites mainly in the Black and Northeast Cape Fear River basins; some sites had very high N and P concentrations as well. Note that the stations primarily drained watersheds that either had small or no sewage treatment plants, but contain numerous swine CAFOs, as well as a considerable number of poultry CAFOs. The mainstem Cape Fear River downstream of Lock and Dam#1 did not show such increases, and actually showed long-term decreases in orthophosphate. The pollutant showing the most widespread increases was fecal coliform bacteria, which increased in the blackwater areas but also in the main Cape Fear River stions from NC11 downstream to the upper estuary. 4 Table of Contents Executive Summary…………………………………………………………………………….1 1.0 Introduction...........................................................................………...............…........5 1.1 Site Description................................................………....................................6 1.2 Report Organization………………………………………………………..…..… 7 2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River and Estuary………………………………………………..……………………..............10 Physical Parameters..…......................………..........................................……....13 Chemical Parameters…....……..……….........................................................…..16 Biological Parameters.......……….....……......................................................…..19 3.0 Nutrient Increases Across Multiple Coastal Plain Stream Stations………………….40 5 1.0 Introduction Michael A. Mallin Aquatic Ecology Laboratory Center for Marine Science University of North Carolina Wilmington The Lower Cape Fear River Program (LCFRP) is a unique science and education program that has a mission to develop an understanding of processes that control and influence the ecology of the Cape Fear River, and to provide a mechanism for information exchange and public education. This program provides a forum for dialogue among the various Cape Fear River user groups and encourages interaction among them. Overall policy is set by an Advisory Board consisting of representatives from citizen’s groups, local government, industries, academia, the business community, and regulatory agencies. This report represents the scientific conclusions of the UNCW researchers participating in this program and does not necessarily reflect opinions of all other program participants. This report focuses on the period January through December 2021. The scientific basis of the LCFRP consists of the implementation of an ongoing comprehensive physical, chemical, and biological monitoring program. Another part of the mission is to develop and maintain a data base on the Cape Fear basin and make use of this data to develop management plans. Presently the program has amassed a 27-year (1995-2021) data base that is available to the public, and is used as a teaching tool. Using this monitoring data as a framework the program goals also include focused scientific projects and investigation of pollution episodes. The scientific aspects of the program are carried out by investigators from the University of North Carolina Wilmington Center for Marine Science. The monitoring program was developed by the Lower Cape Fear River Program Technical Committee, which consists of representatives from UNCW, the North Carolina Division of Environmental Quality, The NC Division of Marine Fisheries, the US Army Corps of Engineers, technical representatives from streamside industries, the Cape Fear Public Utility Authority, Cape Fear Community College, Cape Fear River Watch, the North Carolina Cooperative Extension Service, the US Geological Survey, forestry and agriculture organizations, and others. This integrated and cooperative program was the first of its kind in North Carolina. The physical, chemical and biological data are state-certified and submitted to the US EPA. Broad-scale monthly water quality sampling at 16 stations in the estuary and lower river system began in June 1995 (UNCW Aquatic Ecology Laboratory, directed by Dr. Michael Mallin). Sampling was increased to 34 stations in February of 1996, 35 stations in February 1998, and 36 stations in 2005, then lowered to 33 in 2011; currently it stands at 32 water quality stations. The Lower Cape Fear River Program added another component concerned with studying the benthic macrofauna of the system in 1996. This component is directed by Dr. Martin Posey and Mr. Troy Alphin of the 6 UNCW Biology Department and includes the benefit of additional data collected by the Benthic Ecology Laboratory under various grant-funded projects in the Cape Fear Estuary. These data are collected and analyzed depending upon the availability of funding. The third major biotic component (added in January 1996) was an extensive fisheries program directed by Dr. Mary Moser of the UNCW Center for Marine Science Research, with subsequent (1999) overseeing by Mr. Michael Williams and Dr. Thomas Lankford of UNCW-CMS. This program involved cooperative sampling with the North Carolina Division of Marine Fisheries and the North Carolina Wildlife Resources Commission. The fisheries program ended in December 1999, but was renewed with additional funds from the Z. Smith Reynolds Foundation from spring – winter 2000, then ceased. 1.1. Site Description The mainstem of the Cape Fear River is formed by the merging of the Haw and the Deep Rivers in Chatham County in the North Carolina Piedmont. However, its drainage basin reaches as far upstream as the Greensboro area (Fig. 1.1). The mainstem of the river has been altered by the construction of several dams and water control structures. In the Coastal Plain, the river is joined by two major tributaries, the Black and the Northeast Cape Fear Rivers (Fig. 1.1). These 5th order blackwater streams drain extensive riverine swamp forests and add organic color to the mainstem. The watershed (about 9,164 square miles) is the most heavily industrialized in North Carolina with 203 permitted wastewater discharges with a permitted flow of approximately 429 million gallons per day, and (as of 2010) over 2.07 million people residing in the basin (NCDENR Basinwide Information Management System (BIMS) & 2010 Census). Approximately 23% of the land use in the watershed is devoted to agriculture and livestock production (2006 National Land Cover Dataset), with livestock production dominated by swine and poultry operations. Thus, the watershed receives considerable point and non-point source loading of pollutants. However, the estuary is a well-flushed system, with flushing time ranging from 1 to 22 days with a median flushing time of about seven days, much shorter than the other large N.C. estuaries to the north (Ensign et al. 2004). Water quality is monitored by boat at eight stations in the Cape Fear Estuary (from Navassa to Southport) and one station in the Northeast Cape Fear Estuary (Table 1.1; Fig. 1.1). We note that after July 2011 sampling was discontinued at estuarine stations M42 and SPD, per agreement with the North Carolina Division of Water Quality; and in 2012 sampling was expanded at Smith Creek at the Castle Hayne Road bridge (Table 1.1) and initiated at a new site along the South River (SR-WC). Riverine stations sampled by boat include NC11, AC, DP, IC, and BBT (Table 1.1; Fig. 1.1). NC11 is located upstream of any major point source discharges in the lower river and estuary system, and is considered to be representative of water quality entering the lower system (we note that the City of Wilmington and portions of Brunswick County get their drinking water from the river just upstream of Lock and Dam #1). Station BBT is located on the Black River between Thoroughfare (a stream connecting the Cape Fear and Black Rivers) and the mainstem Cape Fear, and is influenced by both rivers. We 7 consider B210 and NCF117 to represent water quality entering the lower Black and Northeast Cape Fear Rivers, respectively. Data has also been collected at stream and river stations throughout the Cape Fear, Northeast Cape Fear, and Black River watersheds (Table 1.1; Fig. 1.1; Mallin et al. 2001). 1.2. Report Organization Section 1 of this report provides a summary and introduction, and Section 2 of this report presents a detailed overview of physical, chemical, and biological water quality data from the 32 individual stations, and provides tables of raw data as well as figures showing spatial or temporal trends. LCFRP data are freely available to the public. The LCFRP has a website that contains maps and an extensive amount of past water quality, benthos, and fisheries data gathered by the Program available at: www.uncw.edu/cms/aelab/LCFRP/. Additionally, there is an on-line data base. http://lcfrp.uncw.edu/riverdatabase/. Section 3 provides a long term analysis of concerning increases in nutrients, chlorophyll a and fecal coliform bacteria in the Black and Northeast Cape fear watersheds. References Cited Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511. Mallin, M.A., S.H. Ensign, M.R. McIver, G.C. Shank and P.K. Fowler. 2001. Demographic, landscape, and meteorological factors controlling the microbial pollution of coastal waters. Hydrobiologia 460:185-193. 8 Table 1.1 Description of sampling locations for the Lower Cape Fear River Program, 2021. Collected by Boat AEL Station DWR Station #Description Comments County Lat Lon Stream Class.HUC NC11 B8360000 Cape Fear River at NC 11 nr East Arcadia Below Lock and Dam 1, Represents water entering lower basin Bladen 34.3969 -78.2675 WS-IV Sw 03030005 AC B8450000 Cape Fear River at Neils Eddy Landing nr Acme 1 mile below IP, DWR ambient station Columbus 34.3555 -78.1794 C Sw 03030005 DP B8465000 Cape Fear River at Intake nr Hooper Hill AT DAK intake, just above confluence with Black R.Brunswick 34.3358 -78.0534 C Sw 03030005 BBT Black River below Lyons Thorofare UNCW AEL station Pender 34.3513 -78.0490 C Sw ORW+0303005 IC B9030000 Cape Fear River ups Indian Creek nr Phoenix Downstream of several point source discharges Brunswick 34.3021 -78.0137 C Sw 0303005 NAV B9050025 Cape Fear River dns of RR bridge at Navassa Downstream of several point source discharges Brunswick 34.2594 -77.9877 SC 0303005 HB B9050100 Cape Fear River at S. end of Horseshoe Bend nr Wilmington Upstream of confluence with NE Cape Fear River Brunswick 34.2437 -77.9698 SC 0303005 BRR B9790000 Brunswick River dns NC 17 at park nr Belville Near Belville discharge Brunswick 34.2214 -77.9787 SC 03030005 M61 B9800000 Cape Fear River at Channel Marker 61 at Wilmington Downstream of several point source discharges New Hanover 34.1938 -77.9573 SC 03030005 M54 B9795000 Cape Fear River at Channel Marker 54 Downstream of several point source discharges New Hanover 34.1393 -77.946 SC 03030005 M35 B9850100 Cape Fear River at Channel Marker 35 Upstream of Carolina Beach discharge Brunswick 34.0335 -77.937 SC 03030005 M23 B9910000 Cape Fear River at Channel Marker 23 Downstream of Carolina Beach discharge Brunswick 33.9456 -77.9696 SA HQW 03030005 M18 B9921000 Cape Fear River at Channel Marker 18 Near mouth of Cape Fear River Brunswick 33.913 -78.017 SC 03030005 NCF6 B9670000 NE Cape Fear nr Wrightsboro Downstream of several point source discharges New Hanover 34.3171 -77.9538 C Sw 0303007 Collected by Land 6RC B8740000 Six Runs Creek at SR 1003 nr Ingold Upstream of Black River, CAFOs in watershed Sampson 34.7933 -78.3113 C Sw ORW+03030006 LCO B8610001 Little Coharie Creek at SR 1207 nr Ingold Upstream of Great Coharie, CAFOs in watershed Sampson 34.8347 -78.3709 C Sw 03030006 GCO B8604000 Great Coharie Creek at SR 1214 nr Butler Crossroads Downstream of Clinton, CAFOs in watershed Sampson 34.9186 -78.3887 C Sw 03030006 SR B8470000 South River at US 13 nr Cooper Downstream of Dunn Sampson 35.156 -78.6401 C Sw 03030006 BRN B8340050 Browns Creek at NC87 nr Elizabethtown CAFOs in watershed Bladen 34.6136 -78.5848 C 03030005 HAM B8340200 Hammond Creek at SR 1704 nr Mt. Olive CAFOs in watershed Bladen 34.5685 -78.5515 C 03030005 COL B8981000 Colly Creek at NC 53 at Colly Pristine area Bladen 34.4641 -78.2569 C Sw 03030006 B210 B9000000 Black River at NC 210 at Still Bluff 1st bridge upstream of Cape Fear River Pender 34.4312 -78.1441 C Sw ORW+03030006 NC403 B9090000 NE Cape Fear River at NC 403 nr Williams Downstream of Mt. Olive Pickle, CAFOs in watershed Duplin 35.1784 -77.9807 C Sw 0303007 PB B9130000 Panther Branch (Creek) nr Faison Downstream of Bay Valley Foods Duplin 35.1345 -78.1363 C Sw 0303007 GS B9191000 Goshen Swamp at NC 11 and NC 903 nr Kornegay CAFOs in watershed Duplin 35.0281 -77.8516 C Sw 0303007 SAR B9191500 NE Cape Fear River SR 1700 nr Sarecta Downstream of several point source discharges Duplin 34.9801 -77.8622 C Sw 0303007 ROC B9430000 Rockfish Creek at US 117 nr Wallace Upstream of Wallace discharge Duplin 34.7168 -77.9795 C Sw 0303007 LRC B9460000 Little Rockfish Creek at NC 11 nr Wallace DWR Benthic station Duplin 34.7224 -77.9814 C Sw 0303007 ANC B9490000 Angola Creek at NC 53 nr Maple Hill DWR Benthic station Pender 34.6562 -77.7351 C Sw 0303007 SR WC B8920000 South River at SR 1007 (Wildcat/Ennis Bridge Road)Upstream of Black River Sampson 34.6402 -78.3116 C Sw ORW+03030006 NCF117 B9580000 NE Cape Fear River at US 117 at Castle Hayne DWR ambient station, Downstream of point source discharges New Hanover 34.3637 -77.8965 B Sw 0303007 SC-CH B9720000 Smith Creek at US 117 and NC 133 at Wilmington Urban runoff, Downstream of Wilmington Northside WWTP New Hanover 34.2586 -77.9391 C Sw 0303007 9 Figure 1.1. Map of the Lower Cape Fear River system and the LCFRP sampling stations. 10 2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River and Estuary 2.1 - Introduction This section of the report includes a discussion of the physical, chemical, and biological water quality parameters, concentrating on the January-December 2021 Lower Cape Fear River Program monitoring period. These parameters are interdependent and define the overall condition of the river. Physical parameters measured during this study included water temperature, dissolved oxygen, field turbidity and laboratory turbidity, total suspended solids (TSS), salinity, conductivity, pH and light attenuation. The chemical makeup of the Cape Fear River was investigated by measuring the magnitude and composition of nitrogen and phosphorus in the water, and metals as requested by NCDEQ. Selected biological parameters including fecal coliform bacteria (in freshwater) or Enterococcus bacteria (in the estuary) and chlorophyll a were examined. 2.2 - Materials and Methods Samples and field parameters collected for the estuarine stations of the Cape Fear River (NAV down through M18) were gathered (when possible) on an ebb tide. This was done so that the data better represented the river water flowing downstream through the system rather than the tidal influx of coastal ocean water. Sample collection and analyses were conducted according to the procedures in the Lower Cape Fear River Program Quality Assurance/Quality Control (QA/QC) manual. Technical Representatives from the LCFRP Technical Committee and representatives from the NC Division of Environmental Quality inspect UNCW laboratory procedures and periodically accompany field teams to verify proper procedures are followed. By agreement with N.C. Division of Environmental Quality, changes have periodically occurred in the sampling regime. Station SC-CH (lower Smith Creek) was added October 2004; sampling was discontinued at Stations M42 and SPD (June 2011); sampling at Stations BCRR and BC117 was discontinued (December 2012); sampling was added at Station SR-WC on the South River (March 2013); and sampling was discontinued at Station LVC2 (July 2015). Special sampling for dissolved metals was initiated at selected stations by NCDEQ in 2015 and is ongoing. Physical Parameters Water Temperature, pH, Dissolved Oxygen, Turbidity, Light, Salinity, Conductivity Field parameters other than light attenuation were measured at each site using a YSI EXO3 or YSI Pro D55. Each parameter is measured with individual probes on the sonde. At stations sampled by boat (see Table 1.1) physical parameters were measured at 0.1 m and at the bottom (up to 12 m); only surface data are reported within. Occasionally, high flow prohibited the sonde from reaching the actual bottom and measurements were taken as deep as possible. At the terrestrially sampled stations (i.e. from bridges or docks) the physical parameters were measured at a depth of 0.1 m. The Aquatic Ecology Laboratory at the UNCW CMS is State-certified by the N.C. Division of Environmental Quality to 11 perform field parameter measurements. The light attenuation coefficient k was determined from data collected on-site using vertical profiles obtained by a Li-Cor LI-1000 integrator interfaced with a Li-Cor LI-193S spherical quantum sensor. Chemical Parameters Nutrients A local State-certified analytical laboratory was contracted to conduct all chemical analyses except for orthophosphate, which is performed at CMS. The following methods detail the techniques used by CMS personnel for orthophosphate analysis. Orthophosphate (PO4-3) Water samples were collected about 0.1 m below the surface in triplicate in amber 125 mL Nalgene plastic bottles and placed on ice. In the laboratory 50 mL (or 25 mL if turbid) of each triplicate was filtered through separate1.0 micron pre-combusted glass fiber filters, which were frozen and later analyzed for chlorophyll a. The triplicate filtrates were pooled in a glass flask, mixed thoroughly, and approximately 100 mL was poured into a 125 mL plastic bottle to be analyzed for orthophosphate. Samples were frozen until analysis. Orthophosphate analyses were performed in duplicate using an approved US EPA method for the Bran-Lubbe AutoAnalyzer (Method 365.5). In this technique the orthophosphate in each sample reacts with ammonium molybdate and anitmony potassium tartrate in an acidic medium (sulfuric acid) to form an anitmony-phospho-molybdate complex. The complex is then reacted with ascorbic acid and forms a deep blue color. The intensity of the color is measured at a wavelength of 880 nm by a colorimeter and displayed on a chart recorder. Standards and spiked samples were analyzed for quality assurance. Biological Parameters Fecal Coliform Bacteria / Enterococcus Fecal coliform bacteria were analyzed by a State-certified laboratory contracted by the LCFRP. Samples were collected approximately 0.1 m below the surface in sterile plastic bottles provided by the contract laboratory and placed on ice for no more than eight hours before analysis. After August 2011 the fecal coliform analysis was changed to Enterococcus bacteria in the estuarine stations downstream of NAV and HB (Stations BRR, M61, M35, M23 and M18). Chlorophyll a The analytical method used to measure chlorophyll a is described in Welschmeyer (1994) and US EPA (1997) and was performed by UNCW Aquatic Ecology Laboratory personnel. Chlorophyll a concentrations were determined utilizing the 1.0 micron filters used for filtering samples for orthophosphate analysis. All filters were wrapped individually in foil, 12 placed in airtight containers and stored in the freezer. During analysis each filter was immersed in 10 mL of 90% acetone for 24 hours, which extracts the chlorophyll a into solution. Chlorophyll a concentration of each solution was measured on a Turner 10-AU fluorometer. The fluorometer uses an optimal combination of excitation and emission bandwidth filters which reduces the errors inherent in the acidification technique. The Aquatic Ecology Laboratory at the CMS is State-certified by the N.C. Division of Environmental Quality for the analysis of chlorophyll a (chlorophyll at three LCFRP stations are required by NCDEQ to be analyzed by state-certified methods); the rest of the large amount of chlorophyll a data presented here were not State-certified. The Aquatic Ecology Laboratory also participates in the chlorophyll a round robin laboratory comparisons when offered by NCDEQ. Biochemical Oxygen Demand (BOD) Five sites were originally chosen for BOD analysis. One site was located at NC11, upstream of International Paper, and a second site was at AC, about 3 miles downstream of International Paper (Fig.1.1). Two sites were located in blackwater rivers (NCF117 and B210) and one site (BBT) was situated in an area influenced by both the mainstem Cape Fear River and the Black River. For the sampling period May 2000-April 2004 additional BOD data were collected at stream stations 6RC, LCO, GCO, BRN, HAM and COL in the Cape Fear and Black River watersheds. In May 2004 those stations were dropped and sampling commenced at ANC, SAR, GS, N403, ROC and BC117 in the Northeast Cape Fear River watershed for several years. BOD analysis was stopped in August 2015 due to insufficient funding; previous BOD results are published (Mallin et al. 2006). Parameter Method NC DEQ Certified Water Temperature SM 2550B-2000 Yes Dissolved Oxygen SM 4500O G-2001 Yes pH SM 4500 H+B-2011 Yes Specific Conductivity SM 2510 B-2011 Yes Lab Turbidity SM 2130 B-2001 Yes Field Turbidity SM 2130 B-2001 No Chlorophyll a EPA 445.0 Rev. 1.2 Yes Biochemical Oxygen Demand SM 5210 B-2001 No Parameter Method NC DEQ Certified Total Nitrogen By addition Nitrate + Nitrite EPA 353.2 Rev 2.0 1993 Yes Total Kjeldahl Nitrogen EPA 351.2 Rev 2.0 1993 Yes 13 Ammonia Nitrogen EPA 350.1 Rev 2.0 1993 Yes Total Phosphorus SM 4500 PF-2012 Yes Orthophosphate EPA 365.5 No Fecal Coliform SM 9222 D-1997 Yes Enterococcus Enterolert IDEXX Yes 2.3 - Results and Discussion This section includes results from monitoring of the physical, biological, and chemical parameters at all stations for the time period January-December 2021. Discussion of the data focuses both on the river channel stations and stream stations, which sometimes reflect poorer water quality than the channel stations. The contributions of the two large blackwater tributaries, the Northeast Cape Fear River and the Black River, are represented by conditions at NCF117 and B210, respectively. The Cape Fear region was not impacted by hurricanes in 2021. Physical Parameters Water temperature Water temperatures at all stations ranged from 5.8 to 29.9oC, and individual station annual averages ranged from 17.2 to 20.2oC (Table 2.1). Highest temperatures occurred during July and lowest temperatures during December. Stream stations were generally cooler than river stations, most likely because of shading and lower nighttime air temperatures affecting the shallower waters. Salinity Salinity at the estuarine stations (NAV through M18; also NCF6 in the Northeast Cape Fear River) ranged from 0.0 to 33.9 practical salinity units (psu) and station annual means ranged from 1.7 to 25.3 psu (Table 2.2). Lowest salinities occurred in spring and early summer of 2021 and highest in fall. The annual mean salinities for 2021 were similar to the twenty-six year average for 1995-2020 (Figure 2.1). Two stream stations, NC403 and PB, had occasional oligohaline conditions due to discharges from pickle production facilities. SC-CH is a blackwater tidal creek that enters the Northeast Cape Fear River just upstream of Wilmington and salinity there ranged from 0.0 to 7.0 psu. Conductivity Conductivity at the estuarine stations ranged from 0.08 to 51.53 mS/cm and from 0.05 to 4.37 mS/cm at the freshwater stations (Table 2.3). Temporal conductivity patterns followed those of salinity. Dissolved ionic compounds increase the conductance of water, therefore, conductance increases and decreases with salinity, often reflecting river flow 14 conditions due to rainfall. Stations PB and NC403 are below industrial discharges, and often have elevated conductivity. Smith Creek (SC-CH) is an estuarine tidal creek and the conductivity values reflect this (Table 2.3). pH System pH values ranged from 3.7 to 8.0 and station annual means ranged from 4.2 (at COL) to 7.8 (Table 2.4). pH was typically lowest upstream due to acidic swamp water inputs and highest downstream as alkaline seawater mixes with the river water. Low pH values at COL predominate because of naturally acidic blackwater inputs in this wetland-rich rural watershed. Dissolved Oxygen Dissolved oxygen (DO) problems have long been a major water quality concern in the lower Cape Fear River and its estuary, and several of the tributary streams. There is an annual dissolved oxygen sag in the main river channel that begins at DP below a paper mill discharge and persists into the mesohaline portion of the estuary (Fig. 2.2). Working synergistically to lower oxygen levels are two factors: lower oxygen carrying capacity in warmer water and increased bacterial respiration (or biochemical oxygen demand, BOD), due to higher temperatures in summer. Unlike other large North Carolina estuaries (the Neuse, Pamlico and New River) the Cape Fear estuary rarely suffers from dissolved oxygen stratification. This is because, despite salinity stratification, the oxygen remains well mixed due to strong estuarine gravitational circulation and high freshwater inputs (Lin et al. 2006). Thus, hypoxia in the Cape Fear is present throughout the water column. Surface concentrations for all sites in 2021 ranged from 1.6 to 11.8 mg/L (both at GS) and station annual means ranged from 5.6 to 9.6 mg/L (Table 2.5). Overall, average dissolved oxygen levels for 2021 were similar to the long-term average (Fig. 2.2). River dissolved oxygen levels were low during the summer and early fall (Table 2.5), occasionally falling below the state standard of 5.0 mg/L at several river and upper estuary stations. NAV, IC, HB, M61 and BRR were below 5.0 mg/L from 8-17% of occasions sampled. Based on number of occasions the river and estuary stations were below 5 mg/L dissolved oxygen UNCW rated NCF6 and and M61 as fair for 2021; the other estuary stations were rated as good. On a year-to-year basis, discharge of BOD waste from the paper/pulp mill just above the AC station, as well as inflow of blackwater from the Northeast Cape Fear and Black Rivers, helps to decrease oxygen in the lower river and upper estuary. Additionally, algal blooms periodically form behind Lock and Dam #1 (including the blue- green algal blooms from 2009-2012), and the chlorophyll a they produce is strongly correlated with BOD at Station NC11 (Mallin et al. 2006); thus algal blooms do contribute to lower DO in the river. As the water reaches the lower estuary higher algal productivity, mixing and ocean dilution help alleviate oxygen problems. Most tributary stations were rated fair or good in 2021, except GS which was rated poor and ANC, SR and SC-CH which were rated fair (Table 2.5). Some hypoxia can be attributed to low summer water conditions and some potentially to CAFO runoff; however 15 point-source discharges also possibly contribute to low dissolved oxygen levels at SR. Hypoxia is thus a continuing problem but improved with only 19% of stations impacted compared to 34% of the sites impacted in 2020. Field Turbidity Field turbidity levels ranged from 0 to 90 Nephelometric turbidity units (NTU) and station annual means ranged from 1 to 16 NTU (Table 2.6). The State standard for estuarine turbidity is 25 NTU, and for freshwater streams 50 NTU (for lakes and reservoirs it is 25 NTU). Highest mean turbidities were at the upper river sites NC11-DP (11-12 NTU), with turbidities generally low in the middle to lower estuary (Figure 2.3). The estuarine stations only exceeded standard in February 2021. For the stream stations ANC measured 82 NTU in May and LCO measured 90 in June. As in the previous year, mean turbidity levels for 2021 were well below the long-term average at all estuary sites (Fig. 2.3). Turbidity was considerably lower in the blackwater tributaries (Northeast Cape Fear River and Black River) than in the mainstem river. Average turbidity levels were low in the freshwater streams. Note: In addition to the laboratory-analyzed turbidity that are required by NCDEQ for seven locations, the LCFRP uses nephelometers designed for field use, which allows us to acquire in situ turbidity from a natural situation. North Carolina regulatory agencies are required to use turbidity values from water samples removed from the natural system, put on ice until arrival at a State-certified laboratory, and analyzed using laboratory nephelometers. Standard Methods (APHA 1995) notes that transport of samples and temperature change alters true turbidity readings. Our analysis of samples using both methods shows that lab turbidity is nearly always lower than field turbidity; thus we do not discuss lab turbidity in this report. Total Suspended Solids (TSS) An altered monitoring plan was developed for the LCFRP in September 2011. These changes were suggested by the NC Division of Environmental Quality (then DWQ). NCDEQ suggested the LCFRP stop monitoring TSS at Stations ANC, GS, 6RC, LCO, SR, BRN, HAM, COL, SR-WC and monitor turbidity instead. DWQ believed turbidity would be more useful than TSS in evaluating water quality at these stations because there are water quality standards for turbidity. TSS is used by the NCDEQ NPDES Unit to evaluate discharges. No LCFRP subscribers discharge near these sites. Total suspended solid (TSS) values system wide ranged from 1.3 to 52.2 mg/L with station annual means from 1.9 to 22.6 mg/L (Table 2.7). The overall highest river values were at NC11, DP and AC (especially in February and March), with higher values downstream through the estuary. In the stream stations TSS was generally considerably lower than the river and estuary. Although total suspended solids (TSS) and turbidity both quantify suspended material in the water column, they do not always go hand in hand. High TSS does not mean high turbidity and vice versa. This anomaly may be explained by the fact that fine clay particles are effective at dispersing light and causing high turbidity readings, 16 while not resulting in high TSS. On the other hand, large organic or inorganic particles may be less effective at dispersing light, yet their greater mass results in high TSS levels. While there is no NC ambient standard for TSS, many years of data from the lower Cape Fear watershed indicates that 25 mg/L can be considered elevated (reached on several occasions in the river and estuary in 2021). The fine silt and clay in the upper to middle estuary sediments are most likely derived from the Piedmont and carried downstream to the estuary, while the sediments in the lowest portion of the estuary are marine-derived sands (Benedetti et al. 2006). Light Attenuation Due to instrumentation problems light attenuation values will not be reported for 2021. Chemical Parameters – Nutrients Total Nitrogen Total nitrogen (TN) is calculated from TKN (see below) plus nitrate; it is not analyzed in the laboratory. TN ranged from 50 (detection limit) to 10,800 µg/L (at ROC) and station annual means ranged from 778 to 3,861 µg/L (at ROC; Table 2.8). Previous research (Mallin et al. 1999) has shown a positive correlation between river flow and TN in the Cape Fear system. In the main river total nitrogen concentrations were highest at NC11, then declining into the lower estuary, most likely reflecting uptake of nitrogen into the food chain through algal productivity and subsequent grazing by planktivores as well as through dilution and marsh denitrification. The highest median TN value at the stream stations was at ROC with 2,025 µg/L; other sites with elevated TN were NC403, ANC, 6RC, GS and LRC. Nitrate+Nitrite Nitrate+nitrite (henceforth referred to as nitrate) is the main species of inorganic nitrogen in the Lower Cape Fear River. Concentrations system wide ranged from 10 (detection limit) to 8,510 µg/L (at ROC) and station annual means ranged from 66 to 2,278 µg/L (at ROC; Table 2.9). The highest average riverine nitrate levels were at NC11 through DP (314-521 µg/L) indicating that much of this nutrient is imported from upstream. Moving downstream, nitrate levels decrease most likely as a result of uptake by primary producers, microbial denitrification in riparian marshes and tidal dilution. Despite this, the rapid flushing of the estuary (Ensign et al. 2004) permits sufficient nitrate to enter the coastal ocean in the plume and contribute to offshore productivity (Mallin et al. 2005). Nitrate can limit phytoplankton production in the lower estuary in summer (Mallin et al. 1999). The blackwater rivers carried lower concentrations of nitrate compared to the mainstem Cape Fear stations; i.e. the Northeast Cape Fear River (NCF117 mean = 78 µg/L) and the Black River (B210 = 277 µg/L). Lowest river nitrate occurred during August-September. In general, the 2021 nitrate concentrations were mixed compared with the long term average, with some sites higher and some sites lower (Fig. 2.4). 17 Several stream stations showed high levels of nitrate on occasion including NC403, ROC, 6RC, LCO and GCO. LCO, GCO and 6RC primarily receive non-point agricultural or animal waste drainage, while point sources a well as non-point contribute to ROC (1.5 MGD), NC403 (1.0 MGD) and PB (0.5 MGD). In general, the stream stations showed elevated nitrate in late winter and early spring. A considerable number of experiments have been carried out by UNCW researchers to assess the effects of nutrient additions to water collected from blackwater streams and rivers (i.e. the Black and Northeast Cape Fear Rivers, and Colly and Great Coharie Creeks). These experiments have collectively found that additions of nitrogen (as either nitrate, ammonium, or urea) significantly stimulate phytoplankton production and BOD increases. Critical levels of these dissolved nutrients were in the range of 200 to 500 µg-N/L (Mallin et al. 2004; Mallin and Cahoon 2020). Thus, we conservatively consider nitrate concentrations exceeding 500 µg-N/L in Cape Fear watershed streams to be potentially problematic to stream environmental health. Ammonium/ammonia Ammonium concentrations ranged from 10 (detection limit) to 1,400 µg/L (at ROC) and station annual means ranged from 33 to 260 µg/L (at ROC, Table 2.11). River areas with the highest mean ammonium levels this monitoring period included AC and DP, which are downstream of a pulp mill discharge, and M54, M23 and M18 in the mid-to-lower estuary. At the stream stations Colly Creek (COL) showed one occasion of excessive ammonium, 900 µg/L in May 2021 (Table 2.10). This station is in a wetland-rich watershed that has a low level of human development. Most previous years have showed generally low levels of ammonium; however, beginning in 2005 a few unusual peaks began to occur, which increased in magnitude and frequency after 2012, particularly in 2016, 2017 and 2018. We do not have a solid explanation for this increase in ammonium. We are aware that White Lake, located in the upper Colly Creek watershed has had problems with eutrophication (NC DEQ 2017), with nearby upper groundwater and surface runoff showing elevated nutrient concentrations (especially ammonium; potentially from failing local sewage infrastructure in the densely-developed area immediately surrounding the lake). General nutrient concentrations in the lake increased over time as well (NCDEQ 2017; Shank and Zamora 2019). Thus, possibly ammonium-rich drainage from this area has made its way down to the COL station. Additional areas with periodic elevated ammonium in 2021 included ROC and ANC (Table 2.11). Total Kjeldahl Nitrogen Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen plus ammonium. TKN ranged from 50 (detection limit) to 3650 µg/L (at B210) and station annual means ranged from 650 to 1,591 µg/L (Table 2.11). TKN concentration decreases ocean-ward through the estuary, likely due to ocean dilution and food chain uptake of nitrogen. Stations with highest median concentrations included COL, ANC and ROC. As with ammonium, upper groundwater in the White Lake drainage contained high TKN (NC DEQ 2017), some of which may have gone downstream. 18 Total Phosphorus Total phosphorus (TP) concentrations ranged from 10 (detection limit) to 1,520 µg/L (at ROC) and station annual means ranged from 102 to 717 µg/L (ROC; Table 2.12). For the mainstem and upper estuary, average TP for 2021 was considerably higher than the 1995-2020 average (Figure 2.5). The experiments discussed above in the nitrate subsection also involved additions of phosphorus, either as inorganic orthophosphate or a combination of inorganic plus organic P. The experiments showed that additions of P exceeding 500 µg/L led to significant increases in bacterial counts, as well as significant increases in BOD over control. Thus, we consider concentrations of phosphorus above 500 µg/L to be potentially problematic to blackwater streams (Mallin et al. 2004; Mallin and Cahoon 2020). Streams frequently exceeding this critical concentration included GCO and ROC. NC403, PB, SR-WC, and BRN each yielded two values exceeding 500 µg/L. Stations NC403, PB and ROC are downstream of wastewater discharges, while ROC, GCO and BRN are in non-point agricultural areas (note that ROC also has a CAFO-rich watershed). Orthophosphate Orthophosphate ranged from 5 to 2,050 µg/L (at LRC) and station annual means ranged from 11 to 396 µg/L (Table 2.13). Much of the main river orthophosphate load is imported into the Lower Cape Fear system from upstream areas, as NC11 or AC typically have high levels; there are also inputs of orthophosphate from the paper mill above AC (Table 2.14. Orthophosphate can bind to suspended materials and is transported downstream via particle attachment; thus high levels of turbidity at the uppermost river stations may be an important factor in the high orthophosphate levels. Turbidity declines toward the lower estuary because of settling, and orthophosphate concentration also declines. In the estuary, primary productivity helps reduce orthophosphate concentrations by assimilation into biomass. Orthophosphate levels typically reach maximum concentrations during summertime, when anoxic sediment releases bound phosphorus. Also, in the Cape Fear Estuary, summer algal productivity is limited by nitrogen, thereby allowing the accumulation of orthophosphate (Mallin et al. 1999). In spring, productivity in the estuary is usually limited by phosphorus (Mallin et al. 1999). ROC, LRC and GCO had the highest stream station orthophosphate concentrations. All of those sites are in mainly non-point source areas. Chemical Parameters - EPA Priority Pollutant Metals The LCFRP had previously sampled for water column metals (EPA Priority Pollutant Metals) on a bimonthly basis. However, as of 2007 this requirement was suspended by the NC Division of Water Quality and these data are no longer regularly collected by the LCFRP. Revised metals sampling (dissolved, not total metals) was re-initiated in late 2015 and has continued periodically upon request from NCDEQ. Results showed that for stations M35 and M23, concentrations of As, Cd, Cr, Cu, Pb, Ni and Zn were below 19 detection limits on all sampling occasions. Iron (Fe) concentrations were measurable but not at harmful levels. M35 and M23 were previously on the 303(d) list being impaired for Copper Arsenic and Nickel. The DWR determined that these sites could be de-listed using the new dissolved metals criteria. There were two metals samples collected in December 2018 at IC and NAV, with no unusual or adversely high concentrations. Samples were also collected at those two sites in June and December 2019. Most metals were below detection limits. Mercury at IC was 3.39 ng/L in June and 2.39 ng/L in December, and Hg at NAV was 2.79 in December 2019. Zinc was 0.012 µg/L at IC in December 2019. Metals were not collected in 2020. In May and September 2021 metals sampling was performed at IC and NAV. All metals were below the detection limit except for Hg, which ranged from 2.49 to 2.76 ng/L at IC, and from 0.624 to 2.39 mg/L at NAV. Biological Parameters Chlorophyll a During this monitoring period, chlorophyll a was low in the river and estuary locations (Table 2.14). The state standard was not exceeded in the river or estuary samples in 2021, and the highest was 25 µg/L at M35 in July. We note that at the upper site NC11 it has been demonstrated that chlorophyll a biomass is significantly correlated with biochemical oxygen demand (BOD5 – Mallin et al. 2006). Multiple statistical approaches demonstrated that chlorophyll a near Lock and Dam #1 is strongly associated with nitrate generated upstream about 100 km, in an area of point source dischargers downstream of Fayetteville (Saul et al. 2019). System wide, chlorophyll a ranged from undetectable to 38 µg/L, and station annual means ranged from 1-12 µg/L. Production of chlorophyll a biomass is usually low to moderate in the rivers and estuary primarily because of light limitation by turbidity in the mainstem (Dubbs and Whalen 2008) and high organic color and low inorganic nutrients in the blackwater tributary rivers. Spatially, along the river mainstem highest values are normally found in the mid-to-lower estuary stations because light becomes more available downstream of the estuarine turbidity maximum (Fig. 2.6). On average, flushing time of the Cape Fear estuary is rapid, ranging from 1-22 days with a median of 6.7 days (Ensign et al. 2004). This does not allow for much settling of suspended materials, leading to light limitation of phytoplankton production. However, under lower-than-average flows there is generally clearer water because of less suspended material and less blackwater swamp inputs. We note that there were a series of problematic cyanobacterial (blue-green algae) blooms of Microcyctis aeruginosa on the mainstem river in summers of 2009-2012 (Isaacs et al. 2014). Such blooms have not recurred in recent years. Phytoplankton blooms occasionally occur at the stream stations, with a few minor blooms occurring at various months in 2021 (Table 2.14). These streams are generally shallow, so vertical mixing does not carry phytoplankton cells down below the critical depth where respiration exceeds photosynthesis. In areas where the forest canopy opens up large 20 blooms can occur. When blooms occur in blackwater streams they can become sources of BOD upon death and decay, reducing further the low summer dissolved oxygen conditions common to these waters (Mallin et al. 2004; 2015; Mallin and Cahoon 2020). No stream station bloom exceeding the state standard of 40 µg/L were recorded, but lesser blooms occurred on occasion at GS, PB, and SR (Table 2.15). Biochemical Oxygen Demand Beginning in 2015 samples for BOD5 and BOD20 are no longer collected for the program due to insufficient funds. Fecal Coliform Bacteria/ Enterococcus bacteria Fecal coliform (FC) bacterial counts ranged from 5 to 7,500 CFU/100 mL and station annual geometric means ranged from 11 to 352 CFU/100 mL (Table 2.16). The state human contact standard (200 CFU/100 mL) was not exceeded in the mainstem river in 2021 (Table 2.16). During 2021 some stream stations showed elevated fecal coliform pollution levels. HAM and PB reached or exceeded 200 CFU/100 mL 50% of the time sampled, GS exceeded 42% of the time; NC403 and LRC 33% of the time, and SAR and ROC 25% of the time sampled. NC403 and PB are located below point source discharges and the other sites are primarily influenced by non-point source pollution. Beginning in 2015 but especially in 2017 COL had a number of unusually high fecal coliform counts; but counts had only one exceedence of the standard in 2021. Enterococcus counts were initiated in the estuary in mid-2011, as this test is now the standard used by North Carolina regulators for swimming in salt waters. Sites covered by this test include BRR, M61, M54, M35, M23 and M18. The State has a single-sample level for Tier II swimming areas in which the enterococci level in a Tier II swimming area shall not exceed a single sample of 276 enterococci per 100 milliliters of water (15A NCAC 18A .3402); the LCFRP is using this standard for the Cape Fear estuary samples in our rating system. As such, in 2021 this standard was exceeded in the estuary samples once only, at M23. Geometric mean enterococci counts for 2021 were lower than those of the 2012-2020 period for the lower Cape Fear Estuary (Fig. 2.7). Overall, elevated fecal coliform and Enterococcus counts are problematic in this system, with 29% of the stations rated as fair or poor in 2021. 2.4 - References Cited APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed. American Public Health Association, Washington, D.C. Benedetti, M.M., M.J. Raber, M.S. Smith and L.A. Leonard. 2006. Mineralogical indicators of alluvial sediment sources in the Cape Fear River basin, North Carolina. Physical Geography 27:258-281. 21 Dubbs, L. L. and S.C. Whalen. 2008. Light-nutrient influences on biomass, photosynthetic potential and composition of suspended algal assemblages in the middle Cape Fear River, USA. International Review of Hydrobiology 93:711-730. Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511. Isaacs, J.D., W.K. Strangman, M.A. Mallin, M.R. McIver, and J.L.C. Wright. 2014. Microcystins and two new micropeptin cyanopeptides produced by unprecedented Microcystis aeruginosa blooms in North Carolina’s Cape Fear River. Harmful Algae 31:82-86. Lin, J. L. Xie, L.J. Pietrafesa, J. Shen, M.A. Mallin and M.J. Durako. 2006. Dissolved oxygen stratification in two microtidal partially-mixed estuaries. Estuarine, Coastal and Shelf Science. 70:423-437. Mallin, M.A. and L.B. Cahoon. 2020. The hidden impacts of phosphorus pollution to streams and rivers. BioScience. 70:315-329. Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1999. Alternation of factors limiting phytoplankton production in the Cape Fear Estuary. Estuaries 22:985-996. Mallin, M.A., M.R. McIver, S.H. Ensign and L.B. Cahoon. 2004. Photosynthetic and heterotrophic impacts of nutrient loading to blackwater streams. Ecological Applications 14:823-838. Mallin, M.A., L.B. Cahoon and M.J. Durako. 2005. Contrasting food-web support bases for adjoining river-influenced and non-river influenced continental shelf ecosystems. Estuarine, Coastal and Shelf Science 62:55-62. Mallin, M.A., V.L. Johnson, S.H. Ensign and T.A. MacPherson. 2006. Factors contributing to hypoxia in rivers, lakes and streams. Limnology and Oceanography 51:690-701. Mallin, M.A., M.R. McIver, A.R. Robuck and A.K. Dickens. 2015. Industrial swine and poultry production causes chronic nutrient and fecal microbial stream pollution. Water, Air and Soil Pollution 226:407, DOI 10.1007/s11270-015-2669-y. NCDEQ 2017. 2017 White Lake Water Quality Investigation, White Lake, Bladen County (Cape Fear Basin). North Carolina Department of Environmental Quality, Division of Water Resources. Saul, B., M.G. Hudgens and M.A. Mallin. 2019. Upstream causes of downstream effects. Journal of the American Statistical Association. https://doi.org/10.1080/01621459.2019.1574226. Shank, G.C. and P. Zamora. 2019. Influence of Groundwater Flows and Nutrient Inputs on White Lake Water Quality, Final Report. 22 U.S. EPA 1997. Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices, 2nd Ed. EPA/600/R-97/072. National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio. Welschmeyer, N.A. 1994. Fluorometric analysis of chlorophyll a in the presence of chlorophyll b and phaeopigments. Limnology and Oceanography 39:1985-1993. 23 Ta b l e 2 . 1 W a t e r t e m p e r a t u r e ( oC) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 7. 9 7. 9 7. 9 8. 3 8. 3 9. 0 10 . 4 10 . 8 JA N 7. 8 7. 9 8. 0 8. 0 8. 3 8. 3 FE B 6. 0 6. 2 6. 4 6. 5 6. 9 8. 0 8. 7 9. 0 FE B 5. 8 6. 0 6. 2 6. 2 6. 2 MA R 10 . 3 10 . 5 10 . 7 11 . 1 11 . 6 11 . 0 11 . 7 11 . 6 MA R 10 . 0 10 . 2 10 . 4 12 . 7 11 . 9 13 . 4 AP R 19 . 8 19 . 8 19 . 7 19 . 8 19 . 3 18 . 8 18 . 8 18 . 9 AP R 19 . 7 19 . 8 20 . 1 19 . 7 19 . 8 21 . 1 MA Y 23 . 1 23 . 2 23 . 1 23 . 2 23 . 1 23 . 3 23 . 1 23 . 1 MA Y 22 . 8 23 . 1 22 . 9 23 . 3 22 . 9 23 . 4 JU N 27 . 3 28 . 0 27 . 4 27 . 0 27 . 0 27 . 3 27 . 2 27 . 1 JU N 27 . 5 27 . 8 27 . 9 27 . 3 28 . 2 27 . 5 JU L 28 . 9 28 . 6 29 . 0 29 . 4 29 . 5 29 . 9 29 . 3 29 . 6 JU L 28 . 8 28 . 8 28 . 0 26 . 9 27 . 4 28 . 3 AU G 26 . 1 26 . 3 26 . 4 27 . 2 27 . 3 27 . 0 27 . 4 27 . 1 AU G 28 . 1 27 . 8 28 . 3 26 . 4 28 . 7 26 . 6 SE P 27 . 9 28 . 1 28 . 7 28 . 0 28 . 1 28 . 0 27 . 8 27 . 9 SE P 23 . 3 23 . 4 23 . 8 24 . 2 24 . 5 24 . 1 OC T 23 . 5 23 . 5 23 . 5 24 . 3 23 . 9 24 . 1 25 . 3 24 . 0 OC T 24 . 2 24 . 5 24 . 0 23 . 9 24 . 7 25 . 8 NO V 19 . 7 19 . 8 20 . 3 19 . 7 20 . 1 19 . 9 19 . 8 19 . 8 NO V 15 . 5 15 . 6 15 . 5 15 . 4 15 . 8 DE C 12 . 5 12 . 8 13 . 0 13 . 3 13 . 6 12 . 9 13 . 2 13 . 5 DE C 10 . 7 10 . 8 11 . 2 11 . 6 11 . 7 12 . 9 me a n 19 . 4 19 . 6 19 . 7 19 . 8 19 . 9 19 . 9 20 . 2 20 . 2 me a n 18 . 7 18 . 8 18 . 9 18 . 8 19 . 2 21 . 1 st d d e v 8. 2 8. 2 8. 2 8. 1 8. 0 7. 9 7. 6 7. 4 st d d e v 8. 4 8. 3 8. 2 7. 7 8. 1 7. 1 me d i a n 21 . 5 21 . 5 21 . 7 21 . 5 21 . 6 21 . 6 21 . 5 21 . 5 me d i a n 21 . 3 21 . 5 21 . 5 21 . 5 21 . 4 23 . 8 ma x 28 . 9 28 . 6 29 . 0 29 . 4 29 . 5 29 . 9 29 . 3 29 . 6 ma x 28 . 8 28 . 8 28 . 3 27 . 3 28 . 7 28 . 3 mi n 6. 0 6. 2 6. 4 6. 5 6. 9 8. 0 8. 7 9. 0 mi n 5. 8 6. 0 6. 2 6. 2 6. 2 8. 3 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 7. 8 7. 9 8. 6 8. 9 8. 7 9. 6 8. 8 11 . 1 11 . 3 JA N 8. 4 8. 9 8. 4 9. 1 8. 5 7. 9 8. 1 9. 1 8. 5 FE B 13 . 1 13 . 2 15 . 1 13 . 3 13 . 0 13 . 1 12 . 7 8. 7 9. 5 FE B 8. 5 10 . 4 9. 1 10 . 8 11 . 0 11 . 5 12 . 3 12 . 4 12 . 4 MA R 15 . 7 16 . 9 18 . 2 16 . 9 18 . 0 20 . 5 17 . 4 14 . 8 14 . 8 MA R 15 . 1 15 . 1 11 . 3 12 . 5 12 . 8 13 . 2 14 . 3 14 . 1 13 . 8 AP R 17 . 5 17 . 5 19 . 4 16 . 6 17 . 6 16 . 6 16 . 4 16 . 3 17 . 2 AP R 21 . 1 20 . 6 19 . 6 20 . 7 20 . 8 22 . 0 21 . 6 19 . 5 18 . 9 MA Y 20 . 5 22 . 0 17 . 7 20 . 3 21 . 0 22 . 4 20 . 0 22 . 1 22 . 9 MA Y 25 . 7 22 . 9 23 . 4 23 . 1 22 . 9 24 . 3 27 . 3 22 . 9 20 . 8 JU N 22 . 5 23 . 8 22 . 7 23 . 8 23 . 9 22 . 7 23 . 1 26 . 5 JU N 25 . 2 23 . 7 25 . 7 25 . 7 25 . 8 26 . 5 26 . 6 22 . 9 21 . 2 JU L 23 . 7 24 . 3 25 . 1 26 . 3 26 . 1 25 . 1 24 . 3 27 . 1 JU L 26 . 6 26 . 9 24 . 5 24 . 5 24 . 5 25 . 3 25 . 6 25 . 8 25 . 1 AU G 25 . 8 27 . 3 26 . 2 28 . 6 28 . 7 31 . 4 26 . 5 27 . 3 29 . 4 AU G 25 . 9 26 . 1 25 . 7 25 . 9 26 . 3 26 . 5 27 . 5 27 . 0 26 . 9 SE P 21 . 3 20 . 6 21 . 9 20 . 8 19 . 8 22 . 1 20 . 4 23 . 8 23 . 3 SE P 21 . 3 19 . 9 26 . 4 26 . 4 26 . 6 27 . 7 26 . 8 20 . 5 20 . 0 OC T 16 . 3 16 . 6 17 . 2 17 . 0 16 . 0 17 . 1 18 . 6 20 . 6 20 . 4 OC T 22 . 5 21 . 5 16 . 3 16 . 3 16 . 0 16 . 2 15 . 9 21 . 3 20 . 6 NO V 13 . 3 13 . 0 11 . 8 13 . 3 13 . 3 15 . 5 15 . 1 15 . 5 NO V 12 . 8 11 . 3 7. 6 7. 2 7. 2 7. 2 7. 8 11 . 0 10 . 5 DE C 9. 4 7. 8 8. 0 9. 0 7. 7 8. 7 9. 7 12 . 1 DE C me a n 17 . 2 17 . 6 17 . 7 17 . 9 17 . 8 18 . 7 17 . 8 18 . 8 18 . 6 me a n 19 . 4 18 . 8 18 . 0 18 . 4 18 . 4 18 . 9 19 . 4 18 . 8 18 . 1 st d d e v 5. 7 6. 3 6. 0 6. 3 6. 5 6. 6 5. 6 6. 6 6. 7 st d d e v 7. 0 6. 4 7. 7 7. 4 7. 5 7. 9 7. 9 6. 1 6. 0 me d i a n 16 . 9 17 . 2 18 . 0 17 . 0 17 . 8 18 . 8 18 . 0 18 . 5 18 . 8 me d i a n 21 . 3 20 . 6 19 . 6 20 . 7 20 . 8 22 . 0 21 . 6 20 . 5 20 . 0 ma x 25 . 8 27 . 3 26 . 2 28 . 6 28 . 7 31 . 4 26 . 5 27 . 3 29 . 4 ma x 26 . 6 26 . 9 26 . 4 26 . 4 26 . 6 27 . 7 27 . 5 27 . 0 26 . 9 mi n 7. 8 7. 8 8. 0 8. 9 7. 7 8. 7 8. 8 8. 7 9. 5 mi n 8. 4 8. 9 7. 6 7. 2 7. 2 7. 2 7. 8 9. 1 8. 5 24 Ta b l e 2 . 2 S a l i n i t y ( p s u ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m e s t u a r i n e s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 6 SC - C H JA N 0. 0 0. 0 0. 0 1. 0 1. 4 4. 5 15 . 8 19 . 8 0. 1 0. 1 FE B 0. 0 0. 0 0. 0 0. 1 0. 6 4. 4 19 . 6 23 . 4 0. 0 MA R 0. 0 0. 0 0. 0 0. 0 0. 7 2. 7 9. 0 9. 4 0. 0 0. 9 AP R 0. 0 0. 2 3. 0 7. 8 8. 4 12 . 2 17 . 5 21 . 3 0. 1 0. 1 MA Y 0. 1 0. 9 3. 3 7. 5 9. 2 14 . 1 22 . 4 26 . 7 0. 9 7. 0 JU N 0. 1 0. 3 1. 6 5. 3 7. 2 13 . 9 23 . 3 27 . 7 0. 1 JU L 0. 1 0. 1 0. 1 2. 5 5. 8 12 . 1 27 . 0 31 . 7 0. 1 AU G 0. 1 0. 1 0. 1 2. 1 3. 8 6. 5 12 . 7 15 . 0 0. 0 0. 1 SE P 9. 9 9. 1 9. 9 13 . 2 17 . 9 24 . 3 30 . 0 33 . 4 0. 2 0. 3 OC T 0. 1 1. 0 2. 8 9. 5 12 . 1 23 . 9 25 . 3 28 . 0 7. 8 6. 9 NO V 6. 5 11 . 2 18 . 6 12 . 8 21 . 2 26 . 0 31 . 4 33 . 9 DE C 7. 9 10 . 8 18 . 2 13 . 7 21 . 8 28 . 1 32 . 3 33 . 7 8. 0 me a n 2. 1 2. 8 4. 8 6. 3 9. 2 14 . 4 22 . 2 25 . 3 1. 7 1. 9 st d d e v 3. 7 4. 6 6. 9 5. 2 7. 6 9. 1 7. 5 7. 8 3. 3 3. 1 me d i a n 0. 1 0. 3 2. 2 6. 4 7. 8 13 . 1 22 . 9 27 . 2 0. 1 0. 2 ma x 9. 9 11 . 2 18 . 6 13 . 7 21 . 8 28 . 1 32 . 3 33 . 9 8. 0 7. 0 mi n 0. 0 0. 0 0. 0 0. 0 0. 6 2. 7 9. 0 9. 4 0. 0 0. 0 25 051015202530 NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 6 SC - C H Salinty (PSU) Fi g u r e 2 . 1 M e a n S a l i n i t y a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m e s t u a r i n e s t a t i o n s 19 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 26 Ta b l e 2 . 3 C o n d u c t i v i t y ( m S / c m ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 0. 0 9 0. 0 9 0. 0 9 2. 0 0 2. 7 4 8. 1 3 25 . 8 8 31 . 9 2 JA N 0. 0 7 0. 0 9 0. 0 9 0. 0 7 0. 0 8 0. 1 0 FE B 0. 0 8 0. 0 9 0. 0 9 0. 1 2 1. 1 8 7. 9 9 31 . 6 6 37 . 5 0 FE B 0. 0 8 0. 0 8 0. 0 8 0. 0 8 0. 1 0 MA R 0. 0 8 0. 0 9 0. 0 9 0. 0 9 1. 2 6 4. 9 6 15 . 3 0 16 . 1 2 MA R 0. 0 8 0. 0 8 0. 0 8 0. 0 6 0. 0 7 0. 0 7 AP R 0. 1 4 0. 3 7 5. 4 5 13 . 2 5 14 . 4 8 20 . 2 9 28 . 3 6 33 . 8 4 AP R 0. 1 0 0. 1 9 0. 1 4 0. 1 0 0. 1 2 0. 1 3 MA Y 0. 1 6 1. 7 0 6. 0 3 13 . 0 4 15 . 7 8 23 . 2 3 35 . 4 0 41 . 6 7 MA Y 0. 1 0 0. 2 2 0. 1 6 0. 1 1 0. 1 3 1. 8 6 JU N 0. 2 6 0. 5 9 3. 0 8 9. 5 7 12 . 6 2 23 . 0 1 36 . 8 4 43 . 1 3 JU N 0. 1 2 0. 1 2 0. 1 2 0. 1 0 0. 1 2 0. 1 3 JU L 0. 1 2 0. 1 6 0. 2 7 4. 6 9 10 . 4 0 20 . 3 8 42 . 6 3 48 . 8 1 JU L 0. 1 1 0. 2 0 0. 1 6 0. 0 8 0. 1 1 0. 1 3 AU G 0. 1 1 0. 1 3 0. 1 2 4. 0 0 7. 6 5 11 . 3 6 21 . 2 7 24 . 6 0 AU G 0. 0 9 0. 0 9 0. 1 2 0. 0 7 0. 1 0 0. 0 8 SE P 16 . 9 4 15 . 6 4 16 . 8 8 22 . 0 2 29 . 1 0 38 . 3 7 46 . 3 5 51 . 0 5 SE P 0. 0 9 0. 1 2 0. 1 5 0. 1 2 0. 1 4 0. 4 8 OC T 0. 1 7 1. 4 6 5. 1 4 16 . 2 5 20 . 1 8 27 . 9 7 39 . 6 1 43 . 6 0 OC T 0. 0 8 0. 2 2 0. 1 4 0. 1 4 0. 3 1 13 . 6 1 NO V 11 . 3 8 19 . 1 8 29 . 9 6 21 . 2 0 33 . 7 9 40 . 5 7 48 . 0 3 51 . 5 3 NO V 0. 1 7 0. 2 2 0. 2 0 0. 2 0 0. 6 7 DE C 13 . 2 5 18 . 2 6 29 . 3 9 22 . 6 2 34 . 6 6 43 . 6 3 49 . 4 8 51 . 2 4 DE C 0. 1 7 0. 2 3 0. 2 5 0. 1 8 0. 2 4 13 . 8 5 me a n 3. 5 7 4. 8 1 8. 0 5 10 . 7 4 15 . 3 2 22 . 4 9 35 . 0 7 39 . 5 8 me a n 0. 1 0 0. 1 6 0. 1 4 0. 1 1 0. 1 8 3. 0 4 st d d e v 6. 3 2 7. 8 3 11 . 1 6 8. 5 6 11 . 9 7 13 . 1 9 10 . 9 0 11 . 2 8 st d d e v 0. 0 3 0. 0 6 0. 0 5 0. 0 4 0. 1 7 5. 6 6 me d i a n 0. 1 5 0. 4 8 4. 1 1 11 . 3 1 13 . 5 5 21 . 7 0 36 . 1 2 42 . 4 0 me d i a n 0. 1 0 0. 1 6 0. 1 4 0. 1 0 0. 1 2 0. 1 3 ma x 16 . 9 4 19 . 1 8 29 . 9 6 22 . 6 2 34 . 6 6 43 . 6 3 49 . 4 8 51 . 5 3 ma x 0. 1 7 0. 2 3 0. 2 5 0. 2 0 0. 6 7 13 . 8 5 mi n 0. 0 8 0. 0 9 0. 0 9 0. 0 9 1. 1 8 4. 9 6 15 . 3 0 16 . 1 2 mi n 0. 0 7 0. 0 8 0. 0 8 0. 0 6 0. 0 7 0. 0 7 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 0. 0 7 0. 1 1 0. 1 0 0. 2 8 0. 5 6 0. 0 9 0. 0 9 0. 0 8 0. 1 6 JA N 0. 0 9 0. 0 5 0. 0 7 0. 1 3 0. 1 0 0. 1 2 0. 0 7 0. 1 0 0. 1 1 FE B 0. 0 7 0. 1 1 0. 1 0 0. 3 9 0. 6 6 0. 0 8 0. 0 9 0. 0 6 0. 0 7 FE B 0. 0 5 0. 0 5 0. 0 4 0. 0 9 0. 0 7 0. 0 8 0. 0 5 0. 0 7 0. 1 1 MA R 0. 0 7 0. 1 2 0. 1 1 0. 3 9 0. 9 4 0. 1 1 0. 1 3 0. 1 2 1. 7 8 MA R 0. 0 8 0. 0 5 0. 0 6 0. 1 3 0. 1 0 0. 1 2 0. 0 7 0. 1 0 0. 1 6 AP R 0. 0 9 0. 1 3 0. 1 2 0. 4 5 0. 4 6 0. 0 8 0. 1 8 0. 1 1 0. 1 7 AP R 0. 0 9 0. 0 6 0. 0 7 0. 1 4 0. 1 0 0. 1 6 0. 1 0 0. 1 1 0. 1 0 MA Y 0. 2 0 0. 3 0 0. 2 2 1. 2 9 3. 9 2 0. 1 6 0. 3 6 0. 2 3 12 . 1 7 MA Y 0. 1 2 0. 0 5 0. 0 8 0. 1 5 0. 1 2 0. 2 6 0. 0 9 0. 1 3 0. 2 5 JU N 0. 0 8 0. 2 2 0. 1 9 0. 5 1 1. 3 7 0. 1 2 0. 2 6 0. 1 2 JU N 0. 0 9 0. 0 6 0. 0 7 0. 1 4 0. 0 8 0. 1 4 0. 0 8 0. 1 2 0. 1 7 JU L 0. 0 8 0. 1 2 0. 1 1 0. 5 4 0. 6 4 0. 1 0 0. 1 1 0. 1 2 JU L 0. 0 7 0. 0 6 0. 0 5 0. 0 9 0. 0 7 0. 0 8 0. 0 5 0. 1 2 0. 2 0 AU G 0. 0 9 0. 2 1 0. 1 9 0. 7 2 2. 4 3 0. 1 2 0. 1 6 0. 1 0 0. 2 3 AU G 0. 0 7 0. 0 6 0. 0 5 0. 0 9 0. 0 8 0. 0 9 0. 0 7 0. 1 1 0. 1 5 SE P 0. 1 9 0. 3 1 0. 2 4 1. 1 0 4. 3 7 0. 1 2 0. 2 2 0. 1 8 0. 5 6 SE P 0. 1 0 0. 0 7 0. 0 7 0. 1 6 0. 1 1 0. 2 0 0. 0 9 0. 1 3 0. 2 0 OC T 0. 1 2 0. 3 0 0. 2 5 0. 5 2 3. 8 9 0. 1 4 0. 4 9 0. 2 5 11 . 9 8 OC T 0. 1 4 0. 0 6 0. 0 9 0. 1 7 0. 1 2 0. 3 9 0. 1 1 0. 1 5 0. 2 3 NO V 0. 1 8 0. 3 3 0. 2 9 1. 3 0 3. 1 5 0. 2 2 0. 5 7 0. 4 0 NO V 0. 1 5 0. 0 6 0. 0 9 0. 2 1 0. 1 3 0. 2 7 0. 1 1 0. 1 5 0. 2 6 DE C 0. 1 5 0. 2 7 0. 2 8 0. 5 2 0. 7 9 0. 1 5 0. 3 1 0. 4 0 DE C me a n 0. 1 2 0. 2 1 0. 1 8 0. 6 7 1. 9 3 0. 1 2 0. 2 5 0. 1 8 3. 3 9 me a n 0. 0 9 0. 0 6 0. 0 7 0. 1 4 0. 1 0 0. 1 7 0. 0 8 0. 1 2 0. 1 8 st d d e v 0. 0 5 0. 0 9 0. 0 7 0. 3 6 1. 5 2 0. 0 4 0. 1 6 0. 1 2 5. 3 9 st d d e v 0. 0 3 0. 0 1 0. 0 2 0. 0 4 0. 0 2 0. 1 0 0. 0 2 0. 0 2 0. 0 6 me d i a n 0. 0 9 0. 2 2 0. 1 9 0. 5 2 1. 1 6 0. 1 2 0. 2 0 0. 1 2 0. 4 0 me d i a n 0. 0 9 0. 0 6 0. 0 7 0. 1 4 0. 1 0 0. 1 4 0. 0 8 0. 1 2 0. 1 7 ma x 0. 2 0 0. 3 3 0. 2 9 1. 3 0 4. 3 7 0. 2 2 0. 5 7 0. 4 0 12 . 1 7 ma x 0. 1 5 0. 0 7 0. 0 9 0. 2 1 0. 1 3 0. 3 9 0. 1 1 0. 1 5 0. 2 6 mi n 0. 0 7 0. 1 1 0. 1 0 0. 2 8 0. 4 6 0. 0 8 0. 0 9 0. 0 6 0. 0 7 mi n 0. 0 5 0. 0 5 0. 0 4 0. 0 9 0. 0 7 0. 0 8 0. 0 5 0. 0 7 0. 1 0 27 Ta b l e 2 . 4 p H 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 6. 5 6. 6 6. 6 6. 6 6. 8 7. 2 7. 9 8. 0 JA N 6. 6 6.8 6. 7 6.3 6. 5 6. 5 FE B 6. 7 6. 8 7. 2 7. 0 7. 5 7. 4 8. 0 8. 0 FE B 6. 1 6.5 6. 7 6.3 6. 5 MA R 6. 7 6. 7 7. 1 6. 7 7. 0 7. 0 7. 4 7. 3 MA R 6. 3 6.5 6. 6 6. 1 6. 3 5. 9 AP R 6. 7 6. 9 6. 9 7. 0 7. 2 7. 5 7. 7 7. 6 AP R 6. 7 6.8 6. 7 6. 3 6. 6 6. 4 MA Y 7. 0 6. 4 7. 0 7. 1 7. 3 7. 7 7. 9 7.9 MA Y 6. 7 7. 1 6. 9 6. 6 6. 8 6. 8 JU N 7. 0 7. 0 6. 9 7. 0 7. 2 7. 6 7. 9 7.9 JU N 7. 0 7. 0 6. 9 6. 4 6. 7 6. 3 JU L 6. 7 6. 8 6. 9 6. 8 7. 2 7.8 7. 9 7.9 JU L 6. 9 7. 0 6. 9 6. 5 6. 7 6. 6 AU G 6. 8 6. 8 6. 6 6. 5 6. 8 7.1 7. 5 7. 6 AU G 6. 5 6. 5 6. 5 6. 1 6. 3 6. 0 SE P 6. 9 7. 0 7. 3 7.1 7. 7 7.9 8. 0 7. 9 SE P 6. 5 6. 7 6. 7 6.4 6. 6 6. 4 OC T 6. 9 7. 3 6. 9 7. 0 7. 3 7. 5 7. 8 7. 9 OC T 6. 5 6.8 6. 5 6.6 6. 6 6. 7 NO V 7. 3 7. 3 7. 5 7. 3 7. 7 7. 9 8. 0 8. 0 NO V 7. 7 7.1 7. 1 7.1 6. 7 DE C 7. 6 7. 4 7. 7 7. 5 8. 0 8. 0 8. 0 7. 9 DE C 7. 6 7.6 7. 9 7.6 7. 7 6. 7 me a n 6. 9 6. 9 7. 1 7. 0 7. 3 7. 6 7. 8 7. 8 me a n 6. 8 6.9 6. 8 6.5 6. 7 6. 4 st d d e v 0. 3 0. 3 0. 3 0. 3 0. 4 0. 3 0. 2 0. 2 st d d e v 0. 5 0.3 0. 4 0.4 0. 4 0. 3 me d i a n 6. 9 6. 9 7. 0 7. 0 7. 3 7. 6 7. 9 7. 9 me d i a n 6. 7 6.8 6. 7 6. 4 6. 6 6. 5 ma x 7. 6 7. 4 7. 7 7. 5 8. 0 8. 0 8. 0 8. 0 ma x 7. 7 7.6 7. 9 7. 6 7. 7 6. 8 mi n 6. 5 6. 4 6. 6 6. 5 6. 8 7. 0 7. 4 7.3 mi n 6. 1 6. 5 6. 5 6. 1 6. 3 5. 9 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 4. 8 6. 6 6. 8 6. 5 6. 7 6. 7 6. 5 6. 2 6. 8 JA N 6.0 3. 7 5.1 5. 9 6. 0 6. 2 6. 3 6. 2 6. 3 FE B 6. 4 6. 8 7. 1 6. 6 6. 7 6. 5 6. 3 5. 5 6. 4 FE B 5.9 4. 0 5.7 6. 4 6. 4 6. 7 6. 6 6. 3 6. 7 MA R 5. 6 6. 8 7. 2 6. 6 6. 8 7. 3 6. 8 6. 6 6. 6 MA R 6.1 4. 1 6. 3 6. 4 6. 5 6. 5 6. 7 6. 4 6. 9 AP R 6. 1 7. 0 7. 1 6. 6 6. 7 6. 6 6. 9 6.2 6. 5 AP R 6. 2 4. 0 6. 3 7. 0 6. 8 7. 0 6. 1 6. 5 6. 4 MA Y 6. 9 7. 2 6. 9 6. 9 6. 8 7. 8 7. 5 7.2 7. 4 MA Y 6. 8 4. 6 6. 5 7. 0 6. 9 7. 0 6. 7 7. 2 7. 5 JU N 5. 7 7. 2 7. 0 7. 0 6. 9 7.4 7. 0 6.3 JU N 6. 4 4. 5 6. 6 7. 1 6. 6 6. 8 6. 5 7. 2 7. 0 JU L 5. 1 6. 7 6. 7 6.7 6. 7 7.0 6. 8 6. 7 JU L 6. 3 4. 2 5. 9 6. 2 6. 0 6. 5 6. 2 7. 0 7. 4 AU G 4. 7 6. 9 6. 7 6. 9 7. 0 7. 4 6. 7 6. 1 6. 8 AU G 6.2 4. 0 5.9 6. 3 6. 5 6. 6 6. 5 6. 8 7. 0 SE P 7. 0 7. 4 7. 3 7. 1 6. 8 7. 4 7. 2 6. 8 6. 9 SE P 5.8 4. 0 6.3 6. 9 6. 9 6. 9 6. 3 7. 0 7. 2 OC T 6. 6 7. 0 6. 6 6. 8 6. 8 7. 6 7. 5 6. 9 6. 9 OC T 6.8 4. 3 6. 7 7. 0 7. 0 7. 0 6. 8 7. 0 7. 2 NO V 6. 9 7. 2 6. 7 7. 2 6. 8 7. 6 7. 4 7.3 NO V 6. 5 4. 3 6. 8 6. 7 6. 8 6. 7 6. 4 6. 9 6. 9 DE C 6. 8 6. 7 6. 6 6. 6 6. 6 7. 0 6. 8 7. 1 DE C me a n 6. 1 7. 0 6. 9 6. 8 6. 8 7. 2 7. 0 6. 6 6. 8 me a n 6.3 4. 2 6.2 6. 6 6. 6 6. 7 6. 5 6. 8 7. 0 st d d e v 0. 9 0. 3 0. 2 0. 2 0. 1 0. 4 0. 4 0. 5 0. 3 st d d e v 0.3 0. 3 0. 5 0. 4 0. 3 0. 3 0. 2 0. 4 0. 4 me d i a n 6. 3 7. 0 6. 9 6. 8 6. 8 7. 4 6. 9 6. 7 6. 8 me d i a n 6.2 4. 1 6. 3 6. 7 6. 6 6. 7 6. 5 6. 9 7. 0 ma x 7. 0 7. 4 7. 3 7. 2 7. 0 7. 8 7. 5 7.3 7. 4 ma x 6. 8 4. 6 6. 8 7. 1 7. 0 7. 0 6. 8 7. 2 7. 5 mi n 4. 7 6. 6 6. 6 6. 5 6. 6 6. 5 6. 3 5. 5 6. 4 mi n 5. 8 3. 7 5.1 5. 9 6.0 6. 2 6. 1 6. 2 6. 3 28 Ta b l e 2 . 5 D i s s o l v e d O x y g e n ( m g / l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 10 . 6 10 . 7 10 . 6 10 . 2 10 . 2 10 . 2 9. 6 9. 4 JA N 11 . 0 10 . 8 10 . 7 10 . 1 10 . 1 9. 3 FE B 11 . 0 11 . 0 10 . 9 10 . 7 10 . 6 10 . 6 9. 8 9. 6 FE B 11 . 7 11 . 5 11 . 4 10 . 5 10 . 8 MA R 10 . 3 10 . 3 10 . 3 9. 7 9. 6 9. 5 9. 4 9. 4 MA R 10 . 5 10 . 4 10 . 3 8. 6 9. 0 8. 3 AP R 6. 9 6. 9 6. 9 6. 8 7. 4 7. 9 8. 2 8. 0 AP R 8. 0 7. 7 7. 4 5. 5 6. 5 5. 8 MA Y 6. 1 6. 2 6. 1 6. 3 6. 8 7. 3 7. 4 7. 1 MA Y 7. 6 7. 3 6. 9 5. 2 6. 2 6. 3 JU N 5. 6 6. 0 5. 3 5. 3 5. 6 6. 5 6. 7 6. 7 JU N 6. 7 6. 4 6. 1 4. 4 5. 4 3. 6 JU L 5. 4 5. 5 5. 8 5. 6 6. 3 7. 7 6. 3 6. 5 JU L 6. 3 5. 9 5. 5 4. 8 5. 1 4. 4 AU G 5. 1 5. 0 4. 8 4. 4 4. 7 5. 4 5. 5 5. 9 AU G 6. 4 6. 0 5. 5 4. 5 5. 0 3. 9 SE P 4. 2 4. 6 5. 7 4. 8 6. 4 7. 3 6. 9 6. 4 SE P 6. 0 6. 1 6. 0 4. 9 5. 6 4. 5 OC T 5. 9 6. 0 5. 4 5. 4 5. 3 5. 8 6. 3 6. 5 OC T 6. 0 5. 0 4. 8 4. 8 4. 9 4. 8 NO V 5. 7 5. 9 6. 2 5. 9 6. 8 7. 1 7. 2 7. 1 NO V 8. 7 8. 3 7. 5 7. 4 7. 4 DE C 8. 2 8. 3 8. 2 8. 4 9. 0 8. 6 8. 5 8. 4 DE C 10 . 6 10 . 1 9. 7 8. 5 8. 9 8. 4 me a n 7. 1 7. 2 7. 2 7. 0 7. 4 7. 8 7. 7 7. 6 me a n 8. 3 8. 0 7. 7 6. 6 7. 1 5. 9 st d d e v 2. 4 2. 3 2. 2 2. 2 2. 0 1. 6 1. 4 1. 3 st d d e v 2. 1 2. 2 2. 3 2. 3 2. 1 2. 1 me d i a n 6. 0 6. 1 6. 2 6. 1 6. 8 7. 5 7. 3 7. 1 me d i a n 7. 8 7. 5 7. 2 5. 4 6. 4 5. 3 ma x 11 . 0 11 . 0 10 . 9 10 . 7 10 . 6 10 . 6 9. 8 9. 6 ma x 11 . 7 11 . 5 11 . 4 10 . 5 10 . 8 9. 3 mi n 4. 2 4. 6 4. 8 4. 4 4. 7 5. 4 5. 5 5. 9 mi n 6. 0 5. 0 4. 8 4. 4 4. 9 3. 6 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 8. 4 10 . 2 11 . 1 10 . 2 10 . 0 10 . 7 9. 4 7. 5 8. 1 JA N 9. 9 9. 0 10 . 1 10 . 1 10 . 1 10 . 4 10 . 2 10 . 5 10 . 6 FE B 9. 7 9. 7 11 . 8 10 . 1 9. 9 10 . 2 8. 8 9. 5 9. 8 FE B 10 . 2 7. 7 9. 9 9. 1 9. 6 9. 7 9. 7 9. 8 9. 8 MA R 7. 0 8. 1 11 . 1 9. 5 8. 7 10 . 2 8. 3 8. 2 8. 5 MA R 7. 8 7. 2 9. 8 9. 5 9. 8 8. 7 9. 0 9. 5 9. 4 AP R 7. 3 7. 9 10 . 0 9. 1 8. 6 9. 3 8. 1 6. 9 6. 8 AP R 5. 6 5. 9 7. 5 7. 6 7. 5 6. 7 4. 1 8. 3 7. 4 MA Y 2. 5 8. 0 3. 4 6. 4 7. 0 9. 4 7. 7 6. 0 6. 6 MA Y 6. 0 4. 7 6. 5 6. 9 7. 6 6. 4 6. 1 8. 5 6. 7 JU N 6. 0 7. 0 3. 7 6. 5 6. 2 8. 3 6. 6 4. 5 JU N 5. 3 6. 0 6. 7 6. 6 6. 5 6. 2 4. 7 7. 9 5. 6 JU L 4. 9 6. 2 4. 6 5. 8 4. 9 7. 0 5. 8 4. 3 JU L 5. 2 5. 7 6. 1 5. 2 5. 6 5. 8 4. 6 7. 4 6. 5 AU G 4. 5 6. 0 1. 6 5. 8 6. 9 8. 3 5. 5 2. 8 3. 9 AU G 5. 3 4. 9 5. 6 4. 6 5. 6 5. 2 3. 9 7. 1 6. 7 SE P 4. 8 8. 7 7. 8 6. 4 4. 9 8. 5 7. 3 4. 4 4. 5 SE P 6. 0 6. 4 6. 1 6. 2 6. 5 6. 2 1. 9 8. 1 7. 4 OC T 2. 7 8. 5 3. 8 6. 8 5. 8 9. 5 6. 2 5. 5 6. 8 OC T 5. 0 6. 2 7. 9 8. 4 8. 5 8. 2 3. 3 7. 9 6. 3 NO V 5. 0 10 . 6 4. 7 8. 3 7. 9 12 . 4 8. 2 6. 9 NO V 8. 1 7. 1 10 . 9 11 . 6 11 . 3 10 . 6 6. 8 10 . 0 7. 7 DE C 4. 6 9. 0 7. 6 8. 4 8. 4 10 . 9 8. 0 7. 9 DE C me a n 5. 6 8. 3 6. 8 7. 8 7. 4 9. 6 7. 5 6. 2 6. 9 me a n 6. 8 6. 4 7. 9 7. 8 8. 1 7. 6 5. 8 8. 6 7. 6 st d d e v 2. 2 1. 5 3. 6 1. 7 1. 8 1. 4 1. 2 2. 0 2. 0 st d d e v 1. 9 1. 3 1. 9 2. 2 1. 9 1. 9 2. 8 1. 1 1. 6 me d i a n 5. 0 8. 3 6. 2 7. 6 7. 5 9. 5 7. 9 6. 5 6. 8 me d i a n 6. 0 6. 2 7. 5 7. 6 7. 6 6. 7 4. 7 8. 3 7. 4 ma x 9. 7 10 . 6 11 . 8 10 . 2 10 . 0 12 . 4 9. 4 9. 5 9. 8 ma x 10 . 2 9. 0 10 . 9 11 . 6 11 . 3 10 . 6 10 . 2 10 . 5 10 . 6 mi n 2. 5 6. 0 1. 6 5. 8 4. 9 7. 0 5. 5 2. 8 3. 9 mi n 5. 0 4. 7 5. 6 4. 6 5. 6 5. 2 1. 9 7. 1 5. 6 29 0123456789 NC 1 1 AC DP IC NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 1 1 7 NC F 6 B2 1 0 BB T Dissolved Oxygen (mg/L) Fi g u r e 2 . 2 M e a n D i s s o l v e d O x y g e n a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m m a i n s t e m st a t i o n s 1 9 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 30 Ta b l e 2 . 6 F i e l d T u r b i d i t y ( N T U ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 5 6 5 5 6 5 4 4 JA N 11 12 13 5 7 4 FE B 26 23 20 27 36 12 12 10 FE B 37 36 27 11 17 MA R 14 14 13 12 19 21 9 8 MA R 28 30 27 9 15 3 AP R 6 7 5 3 3 4 4 4 AP R 5 7 8 5 6 3 MA Y 8 7 7 6 6 6 6 6 MA Y 3 6 7 5 5 5 JU N 14 13 8 5 6 6 4 4 JU N 8 8 8 3 4 2 JU L 8 9 10 8 6 4 2 4 JU L 5 8 11 4 7 10 AU G 9 9 6 3 2 2 1 1 AU G 5 4 4 1 3 2 SE P 7 6 4 3 6 2 1 2 SE P 14 11 6 1 2 5 OC T 7 8 7 6 5 5 4 4 OC T 12 12 8 8 6 5 NO V 11 9 8 7 5 4 6 8 NO V 3 4 5 5 13 DE C 11 8 11 4 5 9 6 7 DE C 2 3 4 3 4 5 me a n 10 . 5 9. 9 8. 7 7. 4 8. 8 6. 7 4. 9 5. 2 me a n 11 . 1 11 . 8 10 . 7 5. 0 7. 4 4. 4 st d d e v 5. 7 4. 8 4. 4 6. 7 9. 6 5. 3 3. 2 2. 7 st d d e v 10 . 9 10 . 5 8. 1 3. 0 4. 9 2. 3 me d i a n 8. 5 8. 5 7. 5 5. 5 6. 0 5. 0 4. 0 4. 0 me d i a n 6. 5 8. 0 8. 0 5. 0 6. 0 4. 5 ma x 26 . 0 23 . 0 20 . 0 27 . 0 36 . 0 21 . 0 12 . 0 10 . 0 ma x 37 . 0 36 . 0 27 . 0 11 . 0 17 . 0 10 . 0 mi n 5. 0 6. 0 4. 0 3. 0 2. 0 2. 0 1. 0 1. 0 mi n 2. 0 3. 0 4. 0 1. 0 2. 0 2. 0 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 5 4 4 6 10 5 5 7 6 JA N 2 2 1 6 3 1 4 13 27 FE B 3 3 1 3 9 7 4 6 7 FE B 7 4 4 5 3 2 3 10 8 MA R 10 4 0 4 7 3 2 3 13 MA R 4 6 0 4 2 0 0 7 2 AP R 13 2 0 4 10 6 2 4 4 AP R 5 4 1 2 4 3 7 8 12 MA Y 82 2 2 2 11 4 0 2 4 MA Y 2 3 0 1 1 3 1 2 3 JU N 27 5 3 2 9 2 7 1 JU N 2 3 2 6 90 3 4 2 42 JU L 16 3 1 3 17 8 10 1 JU L 2 1 3 5 5 0 6 4 3 AU G 17 6 12 2 6 1 4 1 7 AU G 2 0 0 2 1 1 5 7 4 SE P 8 1 11 0 11 3 3 2 4 SE P 3 1 1 3 1 4 2 2 2 OC T 3 3 6 3 7 4 4 3 7 OC T 3 4 2 4 2 3 2 4 3 NO V 6 2 3 1 6 13 3 3 NO V 3 2 2 2 1 1 1 1 4 DE C 6 6 2 5 7 9 6 3 DE C me a n 16 . 3 3. 4 3. 8 2. 9 9. 2 5. 4 4. 2 3. 0 6. 5 me a n 3. 2 2. 7 1. 5 3. 6 10 . 3 1. 9 3. 2 5. 5 10 . 0 st d d e v 21 . 8 1. 6 4. 0 1. 7 3. 1 3. 4 2. 6 1. 9 3. 0 st d d e v 1. 6 1. 7 1. 3 1. 7 26 . 5 1. 4 2. 2 3. 9 12 . 9 me d i a n 9. 0 3. 0 2. 5 3. 0 9. 0 4. 5 4. 0 3. 0 6. 5 me d i a n 3. 0 3. 0 1. 0 4. 0 2. 0 2. 0 3. 0 4. 0 4. 0 ma x 82 . 0 6. 0 12 . 0 6. 0 17 . 0 13 . 0 10 . 0 7. 0 13 . 0 ma x 7. 0 6. 0 4. 0 6. 0 90 . 0 4. 0 7. 0 13 . 0 42 . 0 mi n 3. 0 1. 0 0. 0 0. 0 6. 0 1. 0 0. 0 1. 0 4. 0 mi n 2. 0 0. 0 0. 0 1. 0 1. 0 0. 0 0. 0 1. 0 2. 0 31 0510152025 NC 1 1 AC DP IC NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 1 1 7 NC F 6 B2 1 0 BB T Field Turbidity (NTU) Fi g u r e 2 . 3 M e a n F i e l d T u r b i d i t y a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m m a i n s t e m st a t i o n s , 1 9 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 32 Ta b l e 2 . 7 T o t a l S u s p e n d e d S o l i d s ( m g / L ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 4. 4 5. 0 4. 5 6. 6 8. 3 8. 9 17 . 8 18 . 3 JA N 10 . 0 9.6 11 . 2 4. 9 3. 1 FE B 24 . 2 16 . 7 11 . 8 35 . 4 52 . 2 17 . 0 30 . 0 32 . 4 FE B 46 . 3 40 . 8 40 . 8 17 . 0 MA R 8. 4 13 . 6 9. 6 10 . 0 22 . 5 32 . 7 16 . 2 12 . 2 MA R 27 . 9 23 . 7 23 . 8 11 . 2 2. 5 AP R 5. 9 9. 0 8. 4 8. 1 9. 2 11 . 2 14 . 2 16 . 4 AP R 6. 3 7.1 10 . 9 6. 8 1. 8 MA Y 9. 9 8. 2 10 . 8 11 . 4 12 . 8 22 . 0 24 . 2 24 . 8 MA Y 3. 0 5.2 7. 5 6. 7 13 . 4 JU N 16 . 0 9. 4 10 . 7 9. 9 13 . 0 16 . 2 18 . 3 15 . 5 JU N 6. 5 8. 2 11 . 2 3. 3 3. 3 JU L 4. 8 5. 5 8. 4 9. 8 12 . 5 13 . 7 14 . 5 16 . 6 JU L 3. 6 6. 3 11 . 0 3. 4 9. 7 19 . 0 AU G 8. 9 5. 7 6. 7 6. 5 7. 3 7. 1 6. 3 8.7 AU G 2. 9 2. 5 1. 3 1. 3 1. 3 2. 9 SE P 12 . 5 26 . 0 12 . 6 7. 4 28 . 2 19 . 5 16 . 1 23 . 1 SE P 5. 1 8. 4 5. 0 1.3 1. 3 10 . 2 OC T 4. 5 6. 1 6. 9 12 . 6 10 . 5 13 . 2 28 . 8 21 . 8 OC T 2. 5 1.3 1. 3 1.3 3. 3 10 . 8 NO V 18 . 4 18 . 2 29 . 4 17 . 4 21 . 8 11 . 7 40 . 8 39 . 8 NO V 1. 3 1.3 3. 1 3.1 12 . 6 DE C 45 . 0 20 . 5 24 . 6 26 . 3 19 . 0 47 . 0 32 . 6 41 . 6 DE C 1. 3 3.0 3. 7 3.9 4. 1 10 . 9 me a n 13 . 6 12 . 0 12 . 0 13 . 5 18 . 1 18 . 4 21 . 7 22 . 6 me a n 9. 7 9.8 10 . 9 2.4 6. 9 6. 9 st d d e v 11 . 7 6. 9 7. 4 8. 9 12 . 6 11 . 3 9. 7 10 . 5 st d d e v 13 . 6 11 . 5 11 . 3 1.2 4. 9 4. 9 me d i a n 9. 4 9. 2 10 . 2 10 . 0 12 . 9 15 . 0 18 . 1 20 . 1 me d i a n 4. 4 6.7 9. 2 2. 2 6. 0 5. 8 ma x 45 . 0 26 . 0 29 . 4 35 . 4 52 . 2 47 . 0 40 . 8 41 . 6 ma x 46 . 3 40 . 8 40 . 8 1. 1 3. 7 17 . 0 mi n 4. 4 5. 0 4. 5 6. 5 7. 3 7. 1 6. 3 8.7 mi n 1. 3 1. 3 1. 3 2. 1 5. 3 1. 3 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 1. 3 7. 0 5. 0 3. 6 2. 5 3. 7 5. 1 JA N 2. 8 1. 3 FE B 2. 5 4. 1 7. 0 5. 5 3. 2 3. 4 4. 2 FE B 3.5 1. 3 MA R 5. 2 5. 1 6. 2 2. 5 2. 7 2. 7 19 . 6 MA R 3.8 1. 3 AP R 1. 3 4. 8 5. 9 5. 1 3. 6 4. 6 10 . 0 AP R 5.6 4. 1 MA Y 19 . 5 4. 0 11 . 5 5. 5 6. 2 3. 7 8. 9 MA Y 1.3 1. 3 JU N 7. 9 4. 4 6. 3 1. 3 1. 3 2. 9 JU N 3.6 4. 6 JU L 4. 6 5. 1 10 . 0 7. 9 11 . 0 1. 3 JU L 2.9 1. 3 AU G 8. 3 3. 4 5. 1 1. 3 1. 3 3. 1 6. 6 AU G 3.4 1. 3 SE P 1. 3 2. 8 8. 9 1. 3 2. 7 4. 8 5. 3 SE P 2.6 1. 3 OC T 3. 2 2. 5 7. 2 2. 8 4. 0 3. 1 13 . 2 OC T 1.3 1. 3 NO V 1. 3 1. 3 5. 3 1. 3 4. 8 4. 3 NO V 1.3 1. 3 DE C 4. 4 6. 6 10 . 6 5. 2 4. 0 DE C me a n 5. 1 4. 1 7. 1 4. 1 4. 0 3. 5 9. 1 me a n 2.9 1. 9 st d d e v 5. 4 1. 5 2. 0 3. 0 2. 6 1. 0 5. 2 st d d e v 1.3 1. 2 me d i a n 3. 2 4. 3 6. 5 3. 2 3. 4 3. 6 7. 8 me d i a n 2.9 1. 3 ma x 19 . 5 7. 0 11 . 5 10 . 6 11 . 0 4. 8 19 . 6 ma x 5.6 4. 6 mi n 1. 3 1. 3 5. 0 1. 3 1. 3 1. 3 4. 2 mi n 1. 3 1. 3 33 Ta b l e 2 . 9 T o t a l N i t r o g e n ( µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 1, 9 6 0 2, 0 5 0 1, 7 3 0 2, 1 6 0 1, 7 8 0 1, 6 6 0 1, 2 4 0 1, 1 1 0 JA N 2, 0 5 0 1, 2 1 0 1, 1 0 0 1, 4 1 0 1, 8 2 0 FE B 1, 3 3 0 1, 2 9 0 1, 1 6 0 1, 3 2 0 1, 1 5 0 1, 2 3 0 56 0 37 0 FE B 1, 2 0 0 1, 0 2 0 98 0 1, 2 0 0 MA R 2, 4 9 0 1, 4 4 0 1, 1 2 0 1, 7 0 0 1, 2 9 0 74 0 58 0 1, 1 0 0 MA R 67 0 73 0 80 0 83 0 1, 2 3 0 AP R 1, 2 9 0 67 0 71 0 1, 1 1 0 63 0 59 0 61 0 56 0 AP R 75 0 81 0 78 0 77 0 1, 0 1 0 MA Y 90 0 78 0 80 0 82 0 73 0 70 0 74 0 73 0 MA Y 1, 7 6 0 95 0 74 0 83 0 99 0 JU N 3, 0 9 0 1, 7 6 0 1, 1 9 0 2, 4 5 0 1, 1 4 0 91 0 1, 1 2 0 1, 2 7 0 JU N 1, 3 0 0 84 0 75 0 1, 0 1 0 93 0 JU L 2, 3 6 0 85 0 1, 2 5 0 1, 4 2 0 86 0 67 0 32 0 52 0 JU L 1, 3 5 0 1, 2 7 0 1, 2 6 0 95 0 97 0 1, 0 8 0 AU G 1, 1 2 0 75 0 81 0 1, 2 5 0 68 0 88 0 73 0 97 0 AU G 1, 4 3 0 76 0 74 0 1, 2 5 0 72 0 1, 0 7 0 SE P 90 0 67 0 3, 7 4 0 76 0 84 0 43 0 67 0 68 0 SE P 1, 9 2 0 1, 0 2 0 88 0 92 0 81 0 96 0 OC T 2, 2 8 0 1, 0 0 0 88 0 1, 7 0 0 85 0 84 0 88 0 43 0 OC T 67 0 67 0 47 0 45 0 96 0 38 0 NO V 1, 3 9 0 87 0 1, 5 6 0 98 0 1, 7 5 0 1, 1 0 0 96 0 1, 1 6 0 NO V 1, 0 5 0 1, 6 1 0 2, 1 4 0 2, 2 2 0 4, 3 7 0 DE C 2, 0 0 0 1, 6 9 0 1, 4 4 0 1, 5 2 0 1, 5 0 0 1, 3 4 0 93 0 88 0 DE C 1, 9 4 0 1, 7 8 0 1, 6 0 0 1, 1 2 0 1, 4 8 0 1, 0 4 0 me a n 1, 7 5 9 1, 1 5 2 1, 3 6 6 1, 4 3 3 1, 1 0 0 92 4 77 8 81 5 me a n 1, 3 4 1 1, 0 5 6 1, 0 2 0 1, 1 5 2 1, 2 8 0 1, 0 5 1 st d d e v 70 5 47 9 81 2 51 3 40 5 35 1 25 9 30 8 st d d e v 49 9 35 2 45 9 59 0 1, 0 0 4 35 0 me d i a n 1, 6 7 5 93 5 1, 1 7 5 1, 3 7 0 1, 0 0 0 86 0 73 5 80 5 me d i a n 1, 3 2 5 98 5 84 0 1, 0 3 5 96 5 1, 0 2 5 ma x 3, 0 9 0 2, 0 5 0 3, 7 4 0 2, 4 5 0 1, 7 8 0 1, 6 6 0 1, 2 4 0 1, 2 7 0 ma x 2, 0 5 0 1, 7 8 0 2, 1 4 0 2, 2 2 0 4, 3 7 0 1, 8 2 0 mi n 90 0 67 0 71 0 76 0 63 0 43 0 32 0 37 0 mi n 67 0 67 0 47 0 45 0 72 0 38 0 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 1, 3 2 0 99 0 3, 0 7 0 2, 0 3 0 1, 6 5 0 2, 0 6 0 1, 2 9 0 96 0 1, 1 8 0 JA N 1, 7 1 0 1, 1 6 0 1, 4 6 0 4, 2 4 0 3, 8 8 0 2, 3 3 0 1, 5 9 0 2, 3 6 0 2, 6 2 0 FE B 1, 7 2 0 1, 4 6 0 2, 6 2 0 5, 0 1 0 1, 9 9 0 2, 2 0 0 1, 7 6 0 1, 2 4 0 1, 1 6 0 FE B 1, 2 6 0 1, 2 9 0 1, 2 9 0 3, 4 6 0 2, 6 2 0 1, 2 2 0 1, 3 2 0 1, 9 0 0 2, 1 0 0 MA R 1, 6 8 0 1, 1 2 0 1, 4 1 0 1, 0 0 0 1, 0 5 0 1, 5 0 0 1, 1 8 0 1, 1 2 0 1, 7 4 0 MA R 1, 1 6 0 1, 5 4 0 1, 1 4 0 98 0 1, 5 2 0 94 0 76 0 1, 0 3 0 1, 3 6 0 AP R 1, 9 3 0 1, 1 6 0 1, 8 9 0 1, 5 1 0 1, 0 5 0 1, 4 9 0 1, 3 2 0 1, 4 1 0 1, 7 7 0 AP R 1, 0 5 0 1, 7 0 0 1, 1 5 0 2, 3 0 0 1, 4 9 0 1, 0 1 0 1, 5 0 0 1, 3 0 0 1, 4 6 0 MA Y 2, 3 2 0 1, 2 4 0 1, 1 0 0 1, 1 7 0 1, 3 1 0 1, 5 3 0 2, 9 1 0 1, 1 6 0 1, 4 2 0 MA Y 1, 0 6 0 3, 6 8 0 1, 5 1 0 2, 0 6 0 1, 9 7 0 1, 6 2 0 1, 7 1 0 1, 5 5 0 1, 0 5 0 JU N 2, 5 0 0 1, 6 7 0 1, 4 5 0 1, 3 9 0 2, 2 9 0 1, 3 7 0 2, 2 9 0 1, 4 7 0 JU N 3, 6 5 0 2, 0 6 0 91 0 91 0 1, 2 0 0 1, 1 2 0 1, 4 9 0 1, 2 8 0 1, 1 7 0 JU L 2, 0 0 0 85 0 1, 3 2 0 93 0 1, 2 7 0 1, 1 9 0 1, 1 6 0 97 0 JU L 62 0 1, 2 8 0 1, 3 2 0 1, 1 9 0 1, 1 4 0 68 0 91 0 80 0 53 0 AU G 1, 9 4 0 75 0 1, 1 6 0 74 0 70 0 1, 4 6 0 1, 5 7 0 88 0 88 0 AU G 1, 0 4 0 1, 4 0 0 1, 1 3 0 1, 9 6 0 1, 1 0 0 66 0 97 0 1, 1 4 0 1, 5 4 0 SE P 1, 2 7 0 1, 7 8 0 1, 0 0 0 1, 9 5 0 1, 1 0 0 1, 8 9 0 5, 7 3 0 1, 1 0 0 1, 5 3 0 SE P 1, 4 8 0 1, 2 7 0 88 0 91 0 68 0 1, 9 2 0 85 0 1, 1 9 0 88 0 OC T 49 0 2, 4 4 0 1, 2 8 0 2, 4 7 0 95 0 1, 0 4 0 6, 9 8 0 27 0 81 0 OC T 25 0 36 0 34 0 1, 2 9 0 39 0 4, 4 1 0 38 0 64 0 11 0 NO V 1, 1 2 0 1, 7 3 0 85 0 4, 7 3 0 75 0 82 0 10 , 8 0 0 96 0 NO V 2, 1 7 0 1, 5 1 0 1, 0 3 0 2, 4 3 0 92 0 79 0 58 0 76 0 50 DE C 1, 4 5 0 25 0 1, 5 5 0 2, 6 1 0 1, 6 8 0 1, 1 7 0 9, 3 4 0 79 0 DE C me a n 1, 6 4 5 1, 2 8 7 1, 5 5 8 2, 1 2 8 1, 3 1 6 1, 4 7 7 3, 8 6 1 1, 0 2 8 1, 3 1 1 me a n 1, 4 0 5 1, 5 6 8 1, 1 0 5 1, 9 7 5 1, 5 3 7 1, 5 1 8 1, 0 9 6 1, 2 6 8 1, 1 7 0 st d d e v 55 4 57 5 66 6 1, 4 1 2 49 3 41 0 3, 4 6 4 31 4 36 5 st d d e v 90 2 81 4 32 5 1, 0 9 5 98 7 1, 0 9 6 44 6 51 2 78 2 me d i a n 1, 7 0 0 1, 2 0 0 1, 3 6 5 1, 7 3 0 1, 1 8 5 1, 4 7 5 2, 0 2 5 1, 0 3 5 1, 3 0 0 me d i a n 1, 1 6 0 1, 4 0 0 1, 1 4 0 1, 9 6 0 1, 2 0 0 1, 1 2 0 97 0 1, 1 9 0 1, 1 7 0 ma x 2, 5 0 0 2, 4 4 0 3, 0 7 0 5, 0 1 0 2, 2 9 0 2, 2 0 0 10 , 8 0 0 1, 4 7 0 1, 7 7 0 ma x 3, 6 5 0 3, 6 8 0 1, 5 1 0 4, 2 4 0 3, 8 8 0 4, 4 1 0 1, 7 1 0 2, 3 6 0 2, 6 2 0 mi n 49 0 25 0 85 0 74 0 70 0 82 0 1, 1 6 0 27 0 81 0 mi n 25 0 36 0 34 0 91 0 39 0 66 0 38 0 64 0 50 34 Ta b l e 2 . 1 0 N i t r a t e / N i t r i t e ( µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 70 0 69 0 53 0 67 0 61 0 49 0 18 0 25 0 JA N 67 0 59 0 45 0 66 0 82 0 FE B 65 0 60 0 60 0 70 0 62 0 53 0 34 0 26 0 FE B 66 0 52 0 54 0 59 0 MA R 1, 6 1 0 10 10 69 0 10 10 10 49 0 MA R 30 40 30 60 25 0 AP R 56 0 10 10 47 0 10 10 10 80 AP R 10 10 10 10 10 MA Y 10 10 10 10 10 10 12 0 10 MA Y 80 0 10 10 10 10 JU N 1, 1 1 0 11 0 90 80 0 40 10 20 40 JU N 45 0 10 10 10 10 JU L 46 0 10 10 63 0 10 10 10 10 JU L 54 0 50 0 33 0 14 0 24 0 19 0 AU G 23 0 10 10 34 0 10 10 10 34 0 AU G 65 0 10 10 10 10 10 SE P 30 0 70 17 0 27 0 18 0 10 10 10 SE P 58 0 20 0 40 20 0 18 0 40 OC T 1, 1 6 0 90 50 65 0 10 10 10 22 0 OC T 67 0 67 0 47 0 45 0 47 0 38 0 NO V 53 0 13 0 40 0 11 0 22 0 20 0 10 60 NO V 12 0 42 0 1, 0 9 0 1, 0 6 0 3, 1 6 0 DE C 77 0 67 0 43 0 55 0 33 0 16 0 60 40 DE C 1, 0 7 0 1, 0 5 0 78 0 50 0 84 0 18 0 me a n 67 4 20 1 19 3 49 1 17 2 12 2 66 15 1 me a n 52 1 33 6 31 4 39 3 52 0 19 0 st d d e v 44 4 27 7 22 9 25 4 23 3 19 3 10 2 15 8 st d d e v 32 1 34 2 36 2 37 6 88 1 25 6 me d i a n 60 5 80 70 59 0 25 10 10 70 me d i a n 61 5 31 0 18 5 32 5 21 0 11 0 ma x 1, 6 1 0 69 0 60 0 80 0 62 0 53 0 34 0 49 0 ma x 1, 0 7 0 1, 0 5 0 1, 0 9 0 1, 0 6 0 3, 1 6 0 82 0 mi n 10 10 10 10 10 10 10 10 mi n 10 10 10 10 10 10 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 27 0 12 0 2, 0 2 0 1, 1 1 0 61 0 1, 2 7 0 38 0 16 0 52 0 JA N 1, 0 4 0 90 73 0 3, 3 3 0 2, 9 6 0 1, 6 8 0 79 0 1, 2 0 0 1, 0 7 0 FE B 25 0 44 0 1, 7 0 0 3, 8 7 0 74 0 1, 0 7 0 29 0 13 0 74 0 FE B 25 0 60 54 0 2, 2 6 0 1, 9 7 0 49 0 56 0 85 0 1, 1 4 0 MA R 19 0 30 67 0 90 50 46 0 10 10 80 0 MA R 19 0 50 33 0 23 0 59 0 80 20 22 0 61 0 AP R 19 0 50 60 0 10 0 30 44 0 30 20 55 0 AP R 10 60 37 0 1, 3 7 0 65 0 10 30 0 61 0 40 0 MA Y 14 0 40 30 40 10 20 0 18 0 10 34 0 MA Y 18 0 11 0 56 0 1, 1 0 0 62 0 28 0 31 0 80 0 12 0 JU N 12 0 10 70 60 10 16 0 24 0 18 0 JU N 10 10 10 10 10 10 10 62 0 24 0 JU L 43 0 10 20 10 10 13 0 10 10 JU L 10 30 11 0 37 0 25 0 90 70 33 0 13 0 AU G 38 0 10 40 80 10 20 0 10 10 14 0 AU G 17 0 20 10 0 34 0 18 0 10 90 32 0 38 0 SE P 40 80 0 40 1, 1 1 0 90 63 0 3, 2 5 0 11 0 20 0 SE P 43 0 30 13 0 60 20 94 0 60 55 0 27 0 OC T 19 0 76 0 40 1, 3 6 0 40 13 0 6, 9 8 0 10 0 58 0 OC T 25 0 36 0 34 0 1, 2 9 0 39 0 4, 4 1 0 38 0 64 0 11 0 NO V 40 74 0 40 1, 1 4 0 30 20 8, 5 1 0 80 NO V 51 0 10 37 0 1, 2 1 0 24 0 30 30 76 0 10 DE C 30 25 0 27 0 1, 4 0 0 56 0 49 0 7, 4 5 0 12 0 DE C me a n 18 9 27 2 46 2 86 4 18 3 43 3 2, 2 7 8 78 48 4 me a n 27 7 75 32 6 1, 0 5 2 71 6 73 0 23 8 62 7 40 7 st d d e v 12 9 32 4 69 5 1, 1 1 3 27 8 39 2 3, 3 7 4 64 23 9 st d d e v 30 1 10 0 22 4 1, 0 2 7 92 0 1, 3 2 8 25 7 27 9 38 3 me d i a n 19 0 85 55 60 5 35 32 0 26 5 90 53 5 me d i a n 19 0 50 34 0 1, 1 0 0 39 0 90 90 62 0 27 0 ma x 43 0 80 0 2, 0 2 0 3, 8 7 0 74 0 1, 2 7 0 8, 5 1 0 18 0 80 0 ma x 1, 0 4 0 36 0 73 0 3, 3 3 0 2, 9 6 0 4, 4 1 0 79 0 1, 2 0 0 1, 1 4 0 mi n 30 10 20 10 10 20 10 10 14 0 mi n 10 10 10 10 10 10 10 22 0 10 35 0 10 0 20 0 30 0 40 0 50 0 60 0 70 0 80 0 NC 1 1 AC DP IC NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 1 1 7 NC F 6 B2 1 0 Nitrate + Nitrite (µg/L) Fi g u r e 2 . 4 M e a n N i t r a t e + N i t r i t e a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m m a i n s t e m st a t i o n s , 1 9 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 36 Ta b l e 2 . 1 1 A m m o n i a ( µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 60 50 90 10 0 11 0 70 10 10 JA N 40 40 60 20 30 FE B 10 0 70 11 0 70 11 0 80 10 10 FE B 70 90 50 50 MA R 50 40 70 30 17 0 80 70 10 0 MA R 10 0 10 0 90 70 50 AP R 60 60 90 90 70 80 50 10 AP R 90 22 0 17 0 11 0 10 MA Y 90 90 10 0 10 0 80 60 10 10 MA Y 70 29 0 16 0 12 0 50 JU N 60 60 70 80 15 0 70 10 10 JU N 40 30 50 40 30 JU L 10 10 10 10 0 10 10 10 30 JU L 30 14 0 10 10 10 10 AU G 10 10 10 20 10 10 10 10 AU G 40 30 30 15 0 10 30 SE P 10 10 10 10 20 0 10 16 0 38 0 SE P 90 11 0 13 0 60 70 70 OC T 16 0 12 0 10 0 40 10 10 11 0 49 0 OC T 10 24 0 11 0 90 80 70 NO V 80 50 10 10 10 10 10 10 NO V 42 0 27 0 12 0 12 9 13 0 DE C 10 0 21 0 40 0 27 0 75 0 52 0 90 11 0 DE C 70 50 60 10 90 14 0 me a n 66 65 89 77 14 0 84 46 98 me a n 89 13 4 87 75 67 49 st d d e v 44 56 10 6 71 20 3 14 1 51 16 3 st d d e v 10 8 97 51 59 42 38 me d i a n 60 55 80 75 95 65 10 10 me d i a n 70 10 5 75 75 70 40 ma x 16 0 21 0 40 0 27 0 75 0 52 0 16 0 49 0 ma x 42 0 29 0 17 0 15 0 13 0 14 0 mi n 10 10 10 10 10 10 10 10 mi n 10 30 10 10 10 10 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 15 0 14 0 45 0 15 0 80 80 50 40 30 JA N 50 11 0 60 90 21 0 50 30 39 0 24 0 FE B 60 80 10 16 0 60 60 26 0 80 70 FE B 50 50 10 70 10 10 10 10 0 19 0 MA R 20 0 10 10 10 0 10 30 30 50 30 MA R 50 28 0 30 12 0 60 60 30 70 30 AP R 90 10 10 16 0 50 50 20 11 0 10 AP R 10 60 14 0 40 50 60 10 0 20 50 MA Y 15 0 30 10 70 50 70 40 10 40 MA Y 50 90 0 30 10 20 40 80 10 30 JU N 46 0 30 12 0 50 60 80 26 0 15 0 JU N 10 26 0 30 80 60 30 10 30 60 JU L 12 0 10 10 60 13 0 60 14 0 10 JU L 10 17 0 10 10 10 10 10 10 10 AU G 12 0 10 19 0 10 40 60 50 10 10 AU G 10 50 10 10 10 10 10 10 20 SE P 30 20 20 30 90 10 0 77 0 30 80 SE P 10 40 90 10 0 60 60 80 70 30 OC T 10 90 80 10 0 10 0 20 0 1, 4 0 0 20 10 OC T 70 19 0 10 10 10 30 10 50 40 NO V 60 60 60 60 30 50 90 60 NO V 11 0 30 10 11 0 10 30 10 10 10 DE C 10 10 10 40 10 10 10 10 DE C 70 19 0 10 10 10 30 10 50 40 me a n 12 2 42 82 83 59 71 26 0 48 35 me a n 42 19 4 37 55 43 35 33 68 63 st d d e v 12 2 42 12 9 52 36 47 41 7 45 27 st d d e v 32 23 9 41 44 57 19 34 10 6 74 me d i a n 10 5 25 15 65 55 60 70 35 30 me d i a n 50 14 0 20 55 15 30 10 40 35 ma x 46 0 14 0 45 0 16 0 13 0 20 0 1, 4 0 0 15 0 80 ma x 11 0 90 0 14 0 12 0 21 0 60 10 0 39 0 24 0 mi n 10 10 10 10 10 10 10 10 10 mi n 10 30 10 10 10 10 10 10 10 37 Ta b l e 2 . 1 2 T o t a l K j e l d a h l N i t r o g e n ( µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 1, 2 6 0 1, 3 6 0 1, 2 0 0 1,4 9 0 1, 1 7 0 1, 1 7 0 1, 0 6 0 86 0 JA N 1, 3 8 0 62 0 65 0 75 0 1, 0 0 0 FE B 68 0 69 0 56 0 62 0 53 0 70 0 22 0 11 0 FE B 54 0 50 0 44 0 61 0 MA R 88 0 1, 4 4 0 1, 1 2 0 1, 0 1 0 1, 2 9 0 74 0 58 0 61 0 MA R 64 0 69 0 77 0 77 0 98 0 AP R 73 0 67 0 71 0 64 0 63 0 59 0 61 0 48 0 AP R 75 0 81 0 78 0 77 0 1,0 1 0 MA Y 90 0 78 0 80 0 82 0 73 0 70 0 62 0 73 0 MA Y 96 0 95 0 74 0 83 0 99 0 JU N 1, 9 8 0 1, 6 0 0 1, 1 0 0 1, 6 0 0 1, 1 0 0 91 0 1, 1 0 0 1, 2 3 0 JU N 85 0 84 0 75 0 1, 0 1 0 93 0 JU L 1, 9 0 0 85 0 1, 2 5 0 79 0 86 0 67 0 32 0 52 0 JU L 81 0 77 0 93 0 81 0 73 0 89 0 AU G 89 0 75 0 81 0 91 0 68 0 88 0 73 0 63 0 AU G 78 0 76 0 74 0 1, 2 5 0 72 0 1,0 7 0 SE P 60 0 60 0 3, 5 7 0 49 0 66 0 43 0 67 0 68 0 SE P 1, 3 4 0 82 0 84 0 72 0 63 0 92 0 OC T 1, 1 2 0 91 0 83 0 1,0 5 0 85 0 84 0 88 0 21 0 OC T 50 50 50 50 49 0 50 NO V 86 0 74 0 1, 1 6 0 87 0 1, 5 3 0 90 0 96 0 1, 1 0 0 NO V 93 0 1, 1 9 0 1, 0 5 0 1, 1 6 0 1, 2 1 0 DE C 1, 2 3 0 1, 0 2 0 1, 0 1 0 97 0 1, 1 7 0 1, 1 8 0 87 0 84 0 DE C 87 0 73 0 82 0 62 0 64 0 86 0 me a n 1, 0 8 6 95 1 1, 1 7 7 93 8 93 3 80 9 71 8 66 7 me a n 82 5 72 8 71 3 76 8 76 3 87 0 st d d e v 44 8 33 4 78 4 32 9 31 2 22 0 27 3 32 4 st d d e v 34 8 27 3 25 5 43 1 19 1 29 5 me d i a n 89 5 81 5 1, 0 5 5 89 0 85 5 79 0 70 0 65 5 me d i a n 83 0 76 5 76 0 76 5 74 0 95 5 ma x 1, 9 8 0 1, 6 0 0 3, 5 7 0 1, 6 0 0 1, 5 3 0 1, 1 8 0 1, 1 0 0 1, 2 3 0 ma x 1, 3 8 0 1, 1 9 0 1, 0 5 0 1, 2 5 0 1, 2 1 0 1,0 7 0 mi n 60 0 60 0 56 0 49 0 53 0 43 0 22 0 11 0 mi n 50 50 50 50 49 0 50 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 1, 0 5 0 87 0 1, 0 5 0 92 0 1, 0 4 0 79 0 91 0 80 0 66 0 JA N 67 0 1, 0 7 0 73 0 91 0 92 0 65 0 80 0 1, 1 6 0 1, 5 5 0 FE B 1, 4 7 0 1, 0 2 0 92 0 1, 1 4 0 1, 2 5 0 1, 1 3 0 1, 4 7 0 1, 1 1 0 42 0 FE B 1, 0 1 0 1, 2 3 0 72 0 1, 2 0 0 65 0 73 0 76 0 1, 0 5 0 96 0 MA R 1, 4 9 0 1, 0 9 0 74 0 91 0 1, 0 0 0 1, 0 4 0 1, 1 8 0 1, 1 2 0 94 0 MA R 97 0 1, 4 9 0 81 0 75 0 93 0 86 0 74 0 81 0 75 0 AP R 1, 7 4 0 1, 1 1 0 1, 2 9 0 1, 4 1 0 1, 0 2 0 1, 0 5 0 1, 2 9 0 1, 3 9 0 1, 2 2 0 AP R 1, 0 5 0 1, 6 4 0 78 0 93 0 84 0 1, 0 1 0 1, 2 0 0 69 0 1, 0 6 0 MA Y 2, 1 8 0 1, 2 0 0 1, 0 7 0 1, 1 3 0 1, 3 1 0 1, 3 3 0 2, 7 3 0 1, 1 6 0 1, 0 8 0 MA Y 88 0 3, 5 7 0 95 0 96 0 1,3 5 0 1, 3 4 0 1, 4 0 0 75 0 93 0 JU N 2, 0 8 0 1, 6 7 0 1, 3 8 0 1, 3 3 0 2, 2 9 0 1, 2 1 0 2, 0 5 0 1, 2 9 0 JU N 3, 6 5 0 2, 0 6 0 91 0 91 0 1,2 0 0 1, 1 2 0 1, 4 9 0 66 0 93 0 JU L 1, 5 7 0 85 0 1, 3 0 0 93 0 1, 2 7 0 1, 0 6 0 1, 1 6 0 97 0 JU L 62 0 1, 2 5 0 1, 2 1 0 82 0 89 0 59 0 84 0 47 0 40 0 AU G 1, 5 6 0 75 0 1, 1 2 0 66 0 70 0 1, 2 6 0 1, 5 7 0 88 0 74 0 AU G 87 0 1, 3 8 0 1, 0 3 0 1, 6 2 0 92 0 66 0 88 0 82 0 1, 1 6 0 SE P 1, 2 3 0 98 0 96 0 84 0 1, 0 1 0 1, 2 6 0 2, 4 8 0 99 0 1, 3 3 0 SE P 1, 0 5 0 1, 2 4 0 75 0 85 0 66 0 98 0 79 0 64 0 61 0 OC T 30 0 1, 6 8 0 1, 2 4 0 1, 1 1 0 91 0 91 0 50 17 0 23 0 OC T 50 50 50 50 50 50 50 50 50 NO V 1, 0 8 0 99 0 81 0 3, 5 9 0 72 0 80 0 2, 3 1 0 88 0 NO V 1, 6 6 0 1, 5 1 0 66 0 1, 2 2 0 68 0 76 0 55 0 50 50 DE C 1, 4 2 0 50 1, 2 8 0 1,2 1 0 1, 1 2 0 68 0 1, 8 9 0 67 0 DE C me a n 1, 4 3 1 1, 0 2 2 1, 0 9 7 1,2 6 5 1, 1 3 7 1, 0 4 3 1, 5 9 1 95 3 82 8 me a n 1, 1 3 5 1, 4 9 9 78 2 92 9 82 6 79 5 86 4 65 0 76 8 st d d e v 49 6 42 3 20 8 76 3 41 2 21 0 75 1 32 0 38 6 st d d e v 91 9 84 4 29 1 38 2 33 6 33 6 39 9 35 2 46 2 me d i a n 1, 4 8 0 1, 0 0 5 1, 0 9 5 1, 1 2 0 1, 0 3 0 1, 0 5 5 1, 5 2 0 98 0 84 0 me d i a n 97 0 1, 3 8 0 78 0 91 0 89 0 76 0 80 0 69 0 93 0 ma x 2, 1 8 0 1, 6 8 0 1, 3 8 0 3, 5 9 0 2, 2 9 0 1, 3 3 0 2, 7 3 0 1, 3 9 0 1, 3 3 0 ma x 3, 6 5 0 3, 5 7 0 1, 2 1 0 1, 6 2 0 1,3 5 0 1, 3 4 0 1, 4 9 0 1, 1 6 0 1, 5 5 0 mi n 30 0 50 74 0 66 0 70 0 68 0 50 17 0 23 0 mi n 50 50 50 50 50 50 50 50 50 38 Ta b l e 2 . 1 3 T o t a l P h o s p h o r u s (µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 10 0 36 0 1, 3 9 0 90 80 12 0 34 0 16 0 JA N 89 0 80 0 71 0 82 0 1, 0 3 0 FE B 16 0 16 0 13 0 15 0 20 0 28 0 14 0 11 0 FE B 63 0 75 0 63 0 49 0 MA R 29 0 29 0 27 0 14 0 18 0 16 0 13 0 18 0 MA R 20 0 25 0 16 0 38 0 30 0 AP R 12 0 12 0 10 0 10 0 13 0 60 60 20 AP R 13 0 25 0 14 0 10 0 14 0 MA Y 11 0 11 0 10 0 80 40 60 10 19 0 MA Y 90 16 0 12 0 12 0 70 JU N 36 0 35 0 31 0 23 0 15 0 80 70 10 0 JU N 11 0 12 0 12 0 13 0 10 0 JU L 16 0 19 0 20 0 16 0 17 0 10 0 10 0 12 0 JU L 74 0 26 0 58 0 48 0 32 0 59 0 AU G 80 10 0 16 0 90 90 80 80 13 0 AU G 18 0 90 10 0 24 0 70 13 0 SE P 20 0 20 0 90 60 29 0 70 20 0 10 SE P 22 0 10 0 12 0 13 0 60 25 0 OC T 31 0 22 0 18 0 17 0 11 0 90 60 50 OC T 20 0 10 0 12 0 11 0 16 0 12 0 NO V 17 0 12 0 12 0 13 0 12 0 70 90 90 NO V 24 0 29 0 26 0 27 0 29 0 DE C 20 0 15 0 90 11 0 80 11 0 50 60 DE C 21 0 21 0 23 0 12 0 21 0 10 0 me a n 18 8 19 8 26 2 12 6 13 7 10 7 11 1 10 2 me a n 32 0 28 2 27 4 22 5 26 3 28 3 st d d e v 85 87 34 7 45 64 59 84 56 st d d e v 25 9 23 1 21 8 12 9 21 1 28 9 me d i a n 16 5 17 5 14 5 12 0 12 5 85 85 10 5 me d i a n 20 5 23 0 15 0 18 5 18 5 13 5 ma x 36 0 36 0 1, 3 9 0 23 0 29 0 28 0 34 0 19 0 ma x 89 0 80 0 71 0 48 0 82 0 1, 0 3 0 mi n 80 10 0 90 60 40 60 10 10 mi n 90 90 10 0 11 0 60 70 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 30 0 10 0 90 10 0 11 0 90 13 0 11 0 70 JA N 1, 0 8 0 50 0 82 0 85 0 62 0 56 0 41 0 97 0 1, 0 7 0 FE B 34 0 12 0 15 0 24 0 24 0 19 0 14 0 12 0 50 FE B 90 60 60 10 0 80 16 0 11 0 16 0 18 0 MA R 26 0 28 0 16 0 23 0 32 0 12 0 33 0 25 0 32 0 MA R 60 46 0 60 12 0 33 0 21 0 22 0 14 0 90 AP R 25 0 80 11 0 11 0 30 0 10 0 33 0 18 0 13 0 AP R 29 0 41 0 61 0 47 0 21 0 37 0 13 0 62 0 28 0 MA Y 18 0 12 0 50 90 17 0 13 0 1, 3 4 0 90 10 0 MA Y 15 0 36 0 20 50 40 96 0 30 30 10 0 JU N 33 0 19 0 18 0 18 0 44 0 11 0 85 0 13 0 JU N 43 0 25 0 70 15 0 19 0 35 0 90 11 0 31 0 JU L 47 0 32 0 34 0 53 0 51 0 41 0 52 0 34 0 JU L 90 10 0 70 15 0 70 26 0 60 50 23 0 AU G 42 0 61 0 84 0 72 0 73 0 18 0 56 0 15 0 90 AU G 20 0 50 15 0 14 0 17 0 16 0 60 27 0 17 0 SE P 36 0 34 0 14 0 28 0 22 0 19 0 73 0 10 0 13 0 SE P 57 0 17 0 39 0 61 0 36 0 79 0 11 0 60 16 0 OC T 39 0 25 0 19 0 19 0 18 0 10 0 1, 0 0 0 14 0 14 0 OC T 27 0 15 0 14 0 16 0 70 1, 1 7 0 80 90 31 0 NO V 13 0 23 0 80 30 0 14 0 10 0 1, 5 2 0 14 0 NO V 54 0 24 0 40 27 0 50 58 0 40 90 15 0 DE C 46 0 23 0 90 21 0 26 0 12 0 1, 1 5 0 10 0 DE C me a n 32 4 23 9 20 2 26 5 30 2 15 3 71 7 15 4 12 9 me a n 34 3 25 0 22 1 27 9 19 9 50 6 12 2 23 5 27 7 st d d e v 10 1 13 9 20 5 17 8 17 2 85 44 3 70 78 st d d e v 28 8 15 4 25 6 24 3 17 0 32 6 10 4 28 1 26 1 me d i a n 33 5 23 0 14 5 22 0 25 0 12 0 64 5 13 5 11 5 me d i a n 27 0 24 0 70 15 0 17 0 37 0 90 11 0 18 0 ma x 47 0 61 0 84 0 72 0 73 0 41 0 1, 5 2 0 34 0 32 0 ma x 1, 0 8 0 50 0 82 0 85 0 62 0 1, 1 7 0 41 0 97 0 1, 0 7 0 mi n 13 0 80 50 90 11 0 90 13 0 90 50 mi n 60 50 20 50 40 16 0 30 30 90 39 050 10 0 15 0 20 0 25 0 30 0 35 0 NC 1 1 AC DP IC NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 1 1 7 NC F 6 B2 1 0 Total Phosphorus (µg/L) Fi g u r e 2 . 5 M e a n T o t a l P h o s p h o r u s a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m m a i n s t e m st a t i o n s , 1 9 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 40 Ta b l e 2 . 1 4 O r t h o p h o s p h a t e (µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 20 30 20 30 30 20 20 10 JA N 30 30 30 20 30 FE B 20 20 30 30 30 20 10 10 FE B 30 30 30 20 20 MA R 20 20 20 30 20 20 20 MA R 30 30 30 20 20 30 AP R 50 50 40 40 40 30 30 20 AP R 50 40 60 40 50 50 MA Y 60 50 40 40 40 20 10 10 MA Y 60 10 0 70 50 60 40 JU N 80 70 70 60 40 20 10 0 10 JU N 50 50 50 50 50 50 JU L 50 60 60 70 60 30 20 10 JU L 60 50 70 50 50 50 AU G 50 50 50 60 60 50 40 40 AU G 70 50 50 40 40 60 SE P 40 40 30 40 30 20 20 10 SE P 70 50 50 40 40 40 OC T 15 0 13 0 12 0 80 40 40 30 30 OC T 11 0 14 0 70 70 50 40 NO V 50 50 40 30 30 20 20 10 NO V 14 0 16 0 13 0 12 0 80 DE C 60 50 40 40 50 30 20 20 DE C 10 0 13 0 12 0 70 11 0 30 me a n 54 52 47 47 40 27 28 17 me a n 67 72 63 52 49 42 st d d e v 35 29 27 17 11 10 24 10 st d d e v 34 47 33 28 26 10 me d i a n 50 50 40 40 40 20 20 10 me d i a n 60 50 55 50 50 40 ma x 15 0 13 0 12 0 80 60 50 10 0 40 ma x 14 0 16 0 13 0 12 0 11 0 60 mi n 20 20 20 30 30 20 10 10 mi n 30 30 30 20 20 30 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 21 0 5 20 40 30 30 70 60 20 JA N 10 50 5 30 5 40 5 10 60 FE B 70 30 20 30 20 20 50 50 50 FE B 20 10 5 30 5 20 10 20 20 MA R 90 20 20 40 40 5 10 0 30 30 MA R 20 18 0 10 20 10 40 5 20 20 AP R 14 0 40 30 30 80 5 18 0 50 20 AP R 40 10 0 20 50 20 26 0 5 20 50 MA Y 70 60 20 70 40 50 35 0 90 20 MA Y 50 12 0 20 50 50 57 0 20 20 60 JU N 80 60 40 60 70 30 42 0 70 JU N 50 50 20 70 40 10 0 20 20 80 JU L 21 0 70 60 21 0 5 40 15 0 80 JU L 80 50 20 80 30 90 5 30 12 0 AU G 33 0 80 50 18 0 90 20 5 0 29 0 80 40 AU G 40 40 20 70 30 90 5 40 90 SE P 80 60 40 30 20 40 41 0 30 40 SE P 40 40 30 90 50 43 0 20 30 90 OC T 12 0 10 0 30 60 30 20 69 0 40 30 OC T 50 80 20 80 30 92 0 20 40 90 NO V 50 60 20 50 20 20 92 0 20 NO V 40 50 10 14 0 10 47 0 5 30 80 DE C 90 80 20 70 50 50 11 2 0 50 20 DE C me a n 12 8 55 31 73 41 19 7 39 6 54 30 me a n 40 70 16 65 25 27 5 11 25 69 st d d e v 82 27 14 59 26 58 4 34 6 22 11 st d d e v 19 48 8 34 17 29 0 7 9 31 me d i a n 90 60 25 55 35 30 32 0 50 30 me d i a n 40 50 20 70 30 10 0 5 20 80 ma x 33 0 10 0 60 21 0 90 20 5 0 11 2 0 90 50 ma x 80 18 0 30 14 0 50 92 0 20 40 12 0 mi n 50 5 20 30 5 5 50 20 20 mi n 10 10 5 20 5 20 5 10 20 41 Ta b l e 2 . 1 5 C h l o r o p h y l l a (µg/ l ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC 1 1 AC DP BB T IC NC F 6 JA N 2 2 2 2 3 3 9 13 JA N 2 2 2 1 2 4 FE B 3 3 2 3 4 2 8 9 FE B 4 3 3 2 2 MA R 8 7 8 7 5 5 3 3 MA R 3 3 3 2 2 1 AP R 1 1 2 6 5 6 5 7 AP R 1 1 1 1 1 3 MA Y 1 3 6 6 7 13 11 5 MA Y 1 1 1 1 1 4 JU N 4 8 6 4 8 9 6 6 JU N 1 2 1 1 1 2 JU L 1 2 4 6 16 25 5 8 JU L 2 1 1 1 1 2 AU G 1 1 1 1 2 4 2 3 AU G 2 2 3 1 1 1 SE P 8 11 16 12 18 16 9 6 SE P 1 2 2 1 2 2 OC T 1 1 1 2 3 3 3 3 OC T 1 1 0 0 6 2 NO V 3 4 4 5 4 2 5 5 NO V 1 1 1 0 2 DE C 2 3 3 3 4 4 5 5 DE C 1 0 1 0 1 5 me a n 3 4 5 5 7 8 6 6 me a n 2 2 2 1 2 3 st d d e v 3 3 4 3 5 7 3 3 st d d e v 1 1 1 1 1 1 me d i a n 2 3 4 5 5 5 5 6 me d i a n 1 2 1 1 2 2 ma x 8 11 16 12 18 25 11 13 ma x 4 3 3 2 6 5 mi n 1 1 1 1 2 2 2 3 mi n 1 0 0 0 1 1 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR - W C 6R C LC O GC O SR BR N HA M JA N 2 8 12 2 2 2 2 5 6 JA N 2 3 2 6 11 8 15 7 8 FE B 3 2 6 2 1 1 1 1 2 FE B 1 2 1 1 5 2 4 1 1 MA R 6 2 2 5 4 3 1 1 3 MA R 1 5 1 2 1 1 4 4 5 AP R 6 2 3 6 2 2 2 2 6 AP R 1 3 0 1 1 1 7 3 3 MA Y 15 2 22 7 8 6 9 1 9 MA Y 3 3 0 1 0 3 27 1 2 JU N 4 2 8 15 17 2 1 1 JU N 1 9 1 2 3 3 6 1 1 JU L 4 3 3 12 13 10 5 3 JU L 4 1 1 2 1 3 3 2 1 AU G 2 2 38 5 6 1 0 1 11 AU G 1 1 0 2 1 3 7 2 1 SE P 4 3 13 3 5 2 1 1 2 SE P 1 4 0 1 0 3 6 1 0 OC T 7 20 29 7 24 2 5 2 18 OC T 1 2 0 2 1 1 8 1 0 NO V 1 2 2 2 3 3 2 1 NO V 1 2 1 1 1 1 1 0 0 DE C 1 5 5 8 38 1 2 1 DE C me a n 5 4 12 6 10 3 3 2 7 me a n 2 3 1 2 2 3 8 2 2 st d d e v 4 5 12 4 11 3 3 1 5 st d d e v 1 2 1 1 3 2 7 2 2 me d i a n 4 2 7 6 6 2 2 1 6 me d i a n 1 3 1 2 1 3 6 1 1 ma x 15 20 38 15 38 10 9 5 18 ma x 4 9 2 6 11 8 27 7 8 mi n 1 2 2 2 1 1 0 1 2 mi n 1 1 0 1 0 1 1 0 0 42 0123456789 NC 1 1 AC DP IC NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 NC F 1 1 7 NC F 6 B2 1 0 BB T Chlorophyll a (µg/L) Fi g u r e 2 . 6 M e a n C h l o r o p h y l l a at t h e L o w e r C a p e F e a r R i v e r P r o g r a m m a i n s t e m s t a t i o n s , 19 9 5 -20 2 0 v e r s u s 2 0 2 1 . 19 9 5 - 2 0 2 0 20 2 1 43 Ta b l e 2 . 1 6 F e c a l C o l i f o r m ( c f u / 1 0 0 m L ) a n d E n t e r o c o c c u s ( M P N ) 2 0 2 1 a t t h e L o w e r C a p e F e a r R i v e r P r o g r a m s t a t i o n s . EN T E R O C O C C U S NC 1 1 AC DP BB T IC NC F 6 NA V HB BR R M6 1 M5 4 M3 5 M2 3 M1 8 JA N 23 15 10 5 5 28 10 JA N 10 10 41 10 10 10 FE B 10 5 91 11 0 23 68 82 FE B 31 36 63 10 30 10 MA R 28 19 10 14 28 15 41 MA R 10 63 10 10 10 1 10 AP R 7 2 2 15 37 2 11 AP R 10 10 10 10 10 10 MA Y 5 5 5 10 46 15 26 MA Y 13 4 75 41 10 10 10 JU N 4 8 11 8 37 5 5 JU N 10 10 10 10 20 10 JU L 5 10 12 0 10 0 11 0 59 36 32 JU L 20 41 10 10 1 1 AU G 19 10 10 23 14 68 16 5 10 5 AU G 31 84 75 84 20 10 SE P 19 19 23 5 5 14 76 91 SE P 31 10 10 10 36 6 21 0 OC T 10 28 19 14 55 10 5 73 14 OC T 31 31 10 10 10 10 NO V 5 10 32 50 55 55 73 NO V 10 52 10 10 10 10 DE C 5 14 23 19 5 19 14 37 DE C 10 20 10 10 10 10 me a n 20 19 31 35 27 42 46 44 me a n 28 37 25 16 50 26 st d d e v 27 23 38 32 30 28 44 33 st d d e v 33 26 23 20 99 56 ma x 10 5 91 12 0 10 0 11 0 10 5 16 5 10 5 ma x 13 4 84 75 84 36 6 21 0 mi n 4 2 2 5 5 5 2 5 mi n 10 10 10 10 1 1 Ge o m e a n 11 13 17 23 16 32 26 30 Ge o m e a n 19 28 17 12 17 11 AN C SA R GS NC 4 0 3 PB LR C RO C NC F 1 1 7 SC - C H B2 1 0 CO L SR W C 6R C LC O GC O SR BR N HA M JA N 19 73 5 37 14 19 50 59 32 JA N 22 14 23 86 86 55 41 91 1, 4 0 0 FE B 14 91 5 32 14 10 41 32 23 FE B 10 19 23 41 5 14 41 28 28 0 MA R 44 14 6 17 28 31 38 20 29 84 MA R 32 64 14 10 10 5 23 72 19 5 AP R 74 48 29 44 50 10 8 50 29 31 AP R 5 46 10 24 28 6 24 17 0 54 6 MA Y 86 20 0 98 14 6 64 0 11 0 12 8 28 82 MA Y 42 14 1 35 17 8 33 28 62 65 JU N 27 3 74 23 7 31 0 23 7 27 3 78 19 JU N 28 10 8 37 13 0 81 9 64 11 0 90 60 0 JU L 95 5 54 6 50 0 41 0 63 7 7, 5 0 0 1, 4 1 0 15 8 JU L 32 15 5 13 0 13 5 95 14 5 91 28 0 15 5 AU G 54 6 15 0 29 0 19 0 1, 1 0 0 27 5 32 5 28 1, 2 0 0 AU G 73 68 64 50 0 50 10 0 16 0 20 0 16 5 SE P 13 5 73 28 46 41 0 82 91 14 50 SE P 29 22 5 13 0 77 82 68 86 16 5 50 0 OC T 16 0 41 0 21 0 10 5 0 20 0 64 13 5 28 82 OC T 16 5 11 0 11 3 21 0 12 5 12 0 32 19 0 50 0 NO V 5 82 19 55 28 91 11 0 59 NO V 28 13 0 50 23 32 10 32 82 1, 0 0 0 DE C 68 1, 1 0 0 25 3 68 2 63 7 68 2 59 1 73 DE C me a n 19 8 24 9 14 1 25 3 33 3 77 1 25 2 46 19 8 me a n 42 98 57 11 4 12 2 56 61 13 0 49 1 st d d e v 27 0 29 5 15 1 30 7 33 8 2, 0 3 7 38 2 38 37 9 st d d e v 42 61 44 13 6 22 4 46 43 72 38 5 ma x 19 1, 1 0 0 50 0 1, 0 5 0 1, 1 0 0 7, 5 0 0 1, 4 1 0 15 8 1, 2 0 0 ma x 16 5 22 5 13 0 50 0 81 9 14 5 16 0 28 0 1, 4 0 0 mi n 5 48 5 28 14 10 20 14 23 mi n 5 14 10 10 5 5 23 28 65 Ge o m e a n 81 15 2 57 12 0 13 8 12 6 11 8 37 73 Ge o m e a n 29 75 41 61 44 33 49 10 9 35 2 44 0102030405060 NC 1 1 AC DP IC NA V HB NC F 1 1 7 NC F 6 B2 1 0 BR R M6 1 M5 4 M3 5 M2 3 M1 8 Bacteria (CFU/100 mL) Fi g u r e 2 . 7 G e o m e t r i c M e a n F e c a l C o l i f o r m ( N C 1 1 -B2 1 0 ) a n d E n t e r o c o c c u s ( B R R -M1 8 ) a t th e L C F R P m a i n s t e m s t a t i o n s , 1 9 9 6 -20 2 0 ( E n t e r o 2 0 1 2 -20 1 4 ) v s . 2 0 2 1 . 19 9 6 - 2 0 2 0 20 2 1 45 3.0. Nutrient Increases Across Multiple Coastal Plain Stream Stations 3.1. Introduction The Lower Cape Fear River Program began sampling at selected sites in mid-1995. Since then the Program has built up a robust data set, with many stations sampled monthly since the beginning. Recently we decided to examine some of the data for long term trends, to see if human impacts, such as point source discharges or industrialized animal production (i.e. CAFOs, concentrated animal feeding operations) have affected the water quality. We were concerned that point source discharges may have increased due to increasing human populations in the upper Cape Fear River watershed. We were also concerned that poultry production has increased considerably in North Carolina, especially on the Coastal Plain (Patt 2017). Note that the large point source NPDES dischargers drain to the 6th order Cape Fear River, and the vast majority of swine and poultry CAFOs drain into tributaries of the 5th order Black River basin and the 5th order Northeast Cape Fear River basin (Table 3.1). 3.2. Statistical Analysis We chose to perform several trends analyses using a 20-year data set, running from 2000 to 2019. Although the LCFRP began in mid-1995, between 1996 and 1999 the Cape Fear region was hit by six major hurricanes: Bertha and Fran in 1996, Bonnie in 1998, and Dennis, Floyd and Irene in 1999. The hurricanes had extreme effects on water quality, thus we decided to begin our trend analyses after the direct influence of those storms passed. The LCFRP uses detection limits of 0.020 mg/L (20 ug/L) for nitrate, ammonium and total phosphorus, and 0.200 (200 ug/L) for TKN. For statistical purposes we used one-half of the detection limit in cases where analyses produced results less than the detection limit. As nutrient parameters can be variable over a year’s time, we needed to account for extremes. We chose to analyze trends within the data set by three statistical procedures to account for the variability. The first was to determine the annual medians (i.e. the number in a list where 50% of the observations are above it and 50% of the observations are below it). The median can provide a measure of central tendency that is appropriate to use when the data are not a standard distribution or when there are extreme outliers (Gotelli and Ellison 2004). We used p values of < 0.05 to determine statistical significance. Additionally, graphing the medians and determining linear regressions provides a visually clear trendline when attempting to graph the changes occurring over 20 years (240 monthly data points on a graph is difficult to visualize). Other statistical tests were also applied to the monthly water quality datasets from January 1999 to December 2019 to evaluate if there were any significant increasing or decreasing trends over time. Statistical analyses were computed using R Studio (2020). Linear regressions analyses are a common statistical method to quantify patterns of continuous data (i.e., time-series datasets). There are several assumptions of linear regression analyses that must first be checked before a linear regression model can be 46 run. Linear regression analyses assume that the dataset being used in the model meets a certain set of criteria, one of which is the normality of residuals, or the difference between the observed values and predicted values. To test if the data were normally distributed, a Shapiro-Wilk Normality Test was computed. Non-normal data, including the fecal coliform and nutrient data (nitrate + nitrite, ammonium, orthophosphate, total nitrogen, and total phosphorus), were log-transformed to normalize it for the linear regression models. Single linear regression models assessed the change in concentration for each water quality parameter individually over the 20-year time period. The results of these linear regression models are p-values, which quantified the significance of the trendlines over time (considered significant if p < 0.05), and the regression coefficient values (R2) that indicates the direction of the trend (positive for an increase, negative for a decrease) and strength of the relationship. However, some data were still not normal after the log transformations, and thus non- parametric approaches were also applied as a third test to assess the trends in these timeseries datasets. The nonparametric approach, which does not assume normally distributed data, used in this study was the Mann-Kendall trend test (Kendall, 1938; Hirsch et al., 1982), a common approach to assess trends in long-term water quality monitoring datasets (Berryman et al., 1988; Meals et al., 2011; Mozejko, 2012). The trends assessed were the same as those for the linear regression, the change in water quality parameters over time. The correlation coefficient for the Mann-Kendall trend test is tau (t), which measures the strength of the correlation. For example, significant (p-value < 0.05) positive t values indicate an increasing trend over time, while negative values indicate decreasing trends over time. 3.3. Results and Discussion When examining the resulting statistical data we decided to discuss trends if two of the three statistical methods provided evidence of a significant trend. Most of the discussion below concerns nutrients and fecal coliform bacteria; chlorophyll a is briefly discussed as well. Table 3.1 describes the sites analyzed, their general location and major influencing land use factors. Table 3.2 shows relevant statistical results for sampling stations and nutrient and fecal coliform counts. We only present data here for which 20 years are available. We found some trends among shorter data sets but those are not presented or discussed. We show four sets of linear trends for medians (Figure 3.1 for nitrate, Figure 3.2 for TN, Figure 3.3 for TP and Figure 3.4 for fecal coliforms) which present sites of particular interest. Nitrate: Nitrate significantly increased over the 20-year span at many stations (Fig. 3.1). with particularly sharp increases in Six Runs Creek (6RC), Great Coharie Creek (GCO) and Little Coharie Creek (LCO) in the Black River basin, as well as in the main 5th order collector Black River proper (B210). Those creeks showing particularly large increases all contained large numbers of CAFOs (Table 3.1). In contrast, Colly Creek (COL), which contain only four CAFOs, maintained low nitrate concentrations and showed no median increases (Fig. 3.1), although the other two tests detected slight increases. 47 Strong nitrate increases were also found at NC403, Angola Creek (ANC), Rockfish Creek (ROC) and Little Rockfish Creek (LRC) in the Northeast Cape Fear River basin, which also showed a significant nitrate increase at the 5th order collector site NCF117 near Castle Hayne. CAFOs are abundant in those watersheds as well, but some sites that showed increases (Rockfish Creek and NC403 also had small (0.5 – 1.5 MGD NPDES discharges upstream of the sampling sites. Additionally, there is a 5.4 MGD NPDES discharge located just downstream from the sampling site on ROC, and field crews have noted that during low flow periods discharges from this outfall can flow upstream to the sampling site. Note that NC403, ROC and 6RC all showed very high nitrate concentrations following about 2010 (Fig. 3.1). Nitrate also significantly increased at Brown’s Creek (BRN) and Hammond Creek (HAM) which drain into the mainstem Cape Fear River. The BRN watershed contains three CAFOs, traditional agriculture and drains stormwater from Elizabethtown. The HAM watershed contains13 swine CAFOs, 4 poultry CAFOs and traditional agriculture (Table 3.1). Notably, the main 6th order Cape Fear River proper did not show significant nitrate increases, nor did the estuary. Ammonium: Ammonium only increased at three locations, NC403, LRC and COL. COL is in a wetland-rich watershed that has a low level of human development. Most previous years have showed generally low levels of ammonium; however, beginning in 2005 a few unusual peaks began to occur, which increased in magnitude and frequency after 2012, particularly in 2016, 2017 and 2018. We do not have a solid explanation for this increase in ammonium. We are aware that The Town of White Lake, located in the upper Colly Creek watershed has had problems with old and compromised sewage infrastructure that leaks, and the lake itself has had recent bouts of eutrophication (NC DEQ 2017), with nearby upper groundwater and surface runoff showing elevated nutrient concentrations (Shank and Zamora 2019). We assume ammonium and other nutrients have escaped downstream from the aging infrastructure surrounding White Lake. Ammonium decreased at three sites, GS, SAR and GCO (Table 3.2). Total nitrogen (TN): TN significantly increased (Fig. 3.2) at several stations, although not as many as nitrate and often less strongly as nitrate. Key sites showing notable increases included 6RC, GCO and B210 in the Black River basin, NC403 and ROC in the Northeast Cape Fear basin, and BRN which drains directly into the mainstem Cape Fear River. The mainstem Cape Fear River and estuary did not show TN increases. Decreases in TN were not seen at any of the sites. Orthophosphate: Orthophosphate concentrations increased at a few locations, two in the Northeast Cape Fear River basin (ANC, LRC) and three in the Black River basin (B210, COL and GCO). What was very surprising is that orthophosphate significantly decreased at 10 locations stretching from the uppermost riverine site at NC11 downstream all the way to Channel 48 Marker 54 about mid-estuary (Table 3.2). Decreases were also seen at Sarecta (SAR) and South River (SR). While the reason for decreases at the latter two sides is not clear, the other ten sites are all impacted by major point source outfalls, either in the Piedmont, the upper Coastal Plain, or near Wilmington (Table 3.1). Total phosphorus (TP): There were significant TP increases (Fig. 3.3) at many stations (Table 3.2). Sharp increases were particularly seen at 6RC, GCO, LCO, COL and B210 are in the Black River watershed. COL has very few CAFOs but, as mentioned, is located well downstream from the town of White Lake. Panther Branch (PB), ANC, LRC, NCF117 and NCF6 are in the Northeast Cape Fear River basin. Note that PB is a small watershed with a 0.5 MGD wastewater discharge and little else. NCF6 is actually an upper estuary station a few miles upstream of the City of Wilmington. M35, M23 and M18 are the lowest stations in the Cape Fear River estuary. They did show significant TP increases, but at very low TP concentrations; the reason for this is not evident. Fecal coliform bacteria: By far the pollutant showing the most widespread increases across the system was fecal coliform bacteria, with 19 sampling sites yielding significant increases as determined by two or three statistical tests (Table 3.2). Note that 12 sites showed increases by all three tests. Along the mainstem Cape Fear River, increases were seen at NC11, DP, AC, IC and HB; note that while significant, these increases were slight, with all R2 values < 0.08. The two tributaries downstream of Elizabethtown, BRN and HAM showed highly significant (p < 0.001) and stronger median increases, with R2 at BRN = 0.25 and R2 at HAM = 0.19. Note that the estuarine stations were not included in the 20-year trend analysis because the Program changed from collecting fecal coliform bacteria to Entercoccus bacteria in 2011. In the Black River watershed 6RC, GCO, LCO, COL, SR and B210 all had significant increases, especially strong at 6RC, GCO and LCO. In the Northeast Cape Fear watershed nine sites showed significant increases, with the strongest increases seen at ROC, GS and NC403. Weaker increases were seen at SAR, LRC, NCF6 and NCF117. Chlorophyll a The primary response variable to nutrient inputs is chlorophyll a, a widely used representation of phytoplankton biomass. There were significant increases at several locations, and no significant decreases were seen. However, most of the sites that showed increases based on two or more statistical techniques actually had very low chlorophyll a concentrations. The only sites yielding notably higher concentrations of chlorophyll a were NC403 (R2 = 0.375, p = 0.004 for medians) and SR (R2 = 0.555, p < 0.001 for medians). Notably, significant decreases were not found for chlorophyll a in the data set. 49 3.4. Discussion and Conclusions A clear theme that the data demonstrate is that sampling sites where nutrients showed large and significant increases were in the Black and Northeast Cape Fear River basins. Almost all of these sites has watersheds with abundant swine CAFOs, and, where data were available, abundant poultry CAOs as well (Table 3.1). Such sites included 6RC, GCO and LCO in the Black River basin, and ROC, ANC and ANC in the Northeast Cape Fear River basin. However, we note there were some locations that also had influence from small NPDES sources located upstream of the sampling sites, especially NC403 and ROC. Also, most nutrients did not show significant decreases in the mainstem Cape Fear River from NC11 downstream into the upper estuary (Table 3.2). The principal response variable chlorophyll a showed several statistical increases as noted, but most of those were small. This is likely due to two reasons. First, the lower Cape Fear watershed has physical characteristics that work against long-term bloom formation in that the waters are darkly stained, which inhibits sunlight penetration. Second, in stream sites we know that algal blooms occur especially in summer, but appear to be washed out regularly by the intense thunderstorms that characterize the southeast in summer (see Mallin et al. 2015) for a fuller explanation. The case of orthophosphate was particularly intriguing. There were a few increases in the Black and Northeast Cape Fear basins (ANC, 6RC, COL, B210) and a few deceases (SAR, NC403, SR, BRN). However, the mainstem stations from NC11 downstream through M54 all showed significant decreases (Table 3.2). The reason for this is unclear. This stretch of the lower system is most subject to large NPDES point sources discharges. The fact that orthophosphate trended lower, and the other nutrients showed no increases appears to demonstrate adherence to nutrient discharge limits. In contrast to nutrients, fecal coliform bacteria showed, small, but statistically significant increases in the Cape Fear River sites from NC11 downstream to the upper estuary. The reason for the increases along the mainstem are not clear. Population may be the key; from 2000 to 2020 in the Cape Fear basin (excluding the Black and Northeast Cape Fear basins) human population increased by about 549,000, or a 36% increase (from data to be included in the upcoming NCDEQ Basinwide Plan). Previous research determined that exurban growth leads to fecal bacterial increases in nearby waterways (Alford et al 2016); thus such rapid growth may account for the mainstem bacteria increases. In the Black and Northeast Cape Fear basins, the previously mentioned factors likely accounted for the bacterial pollution as well as nutrient pollution. 3.5. References Cited Alford, J.B., K.G. Debbage, M.A. Mallin and Z.-J. Liu. 2016. Surface water quality and landscape gradients in the North Carolina Cape Fear River basin: the key role of fecal coliform. Southeastern Geographer. 56:428-453. 50 Berryman, D., B. Bobée, D. Cluis and J. Haemmerli, 1988, Nonparametric Tests For Trend Detection In Water Quality Time Series. JAWRA Journal of the American Water Resources Association, 24: 545-556. https://doi.org/10.1111/j.1752- 1688.1988.tb00904.x Gotelli, N.J. and A.M. Ellison. 2004. A Primer of Ecological Statistics. Sinauer Associates, Inc. Publishers. Hirsch, R. M., J.R. Slack & R.A. Smith. 1982. Techniques of trend analysis for monthly water quality data. Water Resources Research, 18(1), 107-121. https://doi.org/10.1029/WR018i001p00107 Kendall, M. G. 1938. A New Measure of Rank Correlation. Biometrika, 30(1/2), 81–93. https://doi.org/10.2307/2332226 Mallin, M.A., S.H. Ensign, M.R. McIver, G.C. Shank and P.K. Fowler. 2001. Demographic, landscape, and meteorological factors controlling the microbial pollution of coastal waters. Hydrobiologia 460:185-193. Mallin, M.A., M.R. McIver, A.R. Robuck and A.K. Dickens. 2015. Industrial swine and poultry production causes chronic nutrient and fecal microbial stream pollution. Water, Air and Soil Pollution 226:407, DOI 10.1007/s11270-015-2669-y. Meals, D.W., J. Spooner, S.A. Dressing and J.B. Harcum. 2011. Statistical analysis for monotonic trends, Tech Notes 6, November 2011. Developed for U.S. Environmental Protection Agency by Tetra Tech, Inc., Fairfax, VA, 23 p. Available online at https://www.epa. gov/polluted-runoff-nonpoint-source-pollution/nonpoint-source-monitoringtechnical-notes. Mozejko, J. 2012. Detecting and Estimating Trends of Water Quality Parameters. In K. Voudouris, & D. Voutsa (Eds.), Water Quality Monitoring and Assessment. IntechOpen. https://doi.org/10.5772/33052 NCDEQ 2017. 2017 White Lake Water Quality Investigation, White Lake, Bladen County (Cape Fear Basin). North Carolina Department of Environmental Quality, Division of Water Resources. Patt, H. 2017. A comparison of PAN and P2O5 produced from poultry, swine and cattle operations in North Carolina. North Carolina Division of Water Resources, Department of Environmental Quality, Raleigh. Shank, G.C. and P. Zamora. 2019. Influence of Groundwater Flows and Nutrient Inputs on White Lake Water Quality, Final Report. 51 Table 3.1. Station descriptions including watershed information (see also Chapter 1, Figure 1.1 and Table 1.1. There is additional information from the Environmental Working Group and the Waterkeeper Alliance; also the NCDEQ website, also see Mallin et al. (2001). ______________________________________________________________________ Site Description ______________________________________________________________________ Black River watershed sites: Note that there are no NPDES point source dischargers upstream of the LCFRP Black River sampling sites. Station SR South River, 3rd order, upper watershed near Fayetteville, approximately 80 swine CAFOs in watershed (but 7 upstream of the sampling site), unknown number of poultry CAFOs, one NPDES discharger upstream of the sampling site, about 14% wetlands coverage. Station COL Colly Creek, 3nd order, watershed approximately 55% wetland coverage; a tributary of the Black River; four swine CAFOs; note the Town of White Lake is in the headwater and has a failing sewage system. Station 6RC Six Runs Creek, 3rd order tributary of the Black River, high influence of CAFOs (179 swine and 107 poultry CAFOs), about 8% wetlands coverage. Station GCO Great Coharie Creek, 3rd order, watershed contains 95 swine CAFOs and an unknown number of poultry CAFOs, about 11% wetlands coverage. Station LCO Little Coharie Creek (LCO) –3rd order, 63 swine CAFOs in basin, unknown number of poultry CAFOs. Station B210 is located in the lower 5th order Black River and is considered the main collector site for the Black River watershed. Northeast Cape Fear River watershed sites NC403 - Northeast Cape Fear River headwaters, 1st order, drains a watershed that hosts nine swine CAFOs, traditional agriculture; grazing cattle, and an NPDES point source wastewater discharge (1 MGD). Station PB - Panther Branch, 1st order tributary of Northeast Cape Fear River, receives a NPDES point source wastewater discharge (0.5 MGD); one poultry CAFO in watershed. Station SAR – Sarecta – located in the upper Northeast Cape Fear River proper. 52 Station AC - Angola Creek, 3rd order, contains 13 swine CAFOs, unknown number of poultry CAFOs, 27% wetlands coverage. Station GS - Goshen Swamp, 3rd order, watershed contains 119 swine CAFOs and an unknown number of poultry CAFOs, 14% wetlands coverage. Station ROC – Rockfish Creek, 4th order, Basin hosts about 74 swine CAFOs, an unknown number of poultry CAFOs and there is a 1.5 MGD point-source discharge (poultry rendering) upstream from our sampling site; note there is a 5.4 MGD municipal discharge into the creek about 10 m downstream of the sampling site, which during low flow backs upstream tour site. This watershed has about 16% wetlands coverage. Station LRC – Little Rockfish Creek, formerly hosted an NPDES discharge but no longer does, mainly a non-point area, unknown number of swine and poultry CAFOs. Station NCF17 is considered the main collector site for the 5th order Northeast Cape Fear River and is upstream of NCF6, fresh but tidal. Station NCF6 is located in the upper estuary of the 5th order Northeast Cape Fear River about 6 miles upstream of Wilmington, generally oligohaline. Main Cape Fear River: The Cape Fear watershed is 9,165 square miles, is the most heavily industrialized in NC with 218 NPDES wastewater discharges with a permitted flow of approximately 425 million gallons per day, and (as of 2020) and an estimated 2.3 million people residing in the basin (this is preliminary information from the Draft Cape Fear River Basin Plan – 11-18-22. The majority of NPDES point sources enter the Cape Fear River upstream of Lock and Dam #1, except for the Wilmington area. Stations NC11, AC, DP and IC are located in the mainstem of the 6th order Cape Fear River, downstream of Lock and Dam #1 to above the Navassa Bridge, just upstream of the City of Wilmington. Stations NAV, HB, BRR, M61, M54, M35, M23 and M18 are located along the Cape Fear Estuary moving downstream from the Navassa Bridge, past Wilmington and the State Port (M61) to the most oceanward station M18. Station M54 is the site closest to the Wilmington south Side wastewater treatment plant discharge along the shore (sampling station is mid-channel). Station BRN - Browns Creek, 2nd order tributary of the Cape Fear River, presence of three swine CAFOs and traditional agriculture; drains stormwater from Elizabethtown (4,000 residents), about 13% wetland coverage. Station HAM - Hammond Creek, 2nd order tributary of the Cape Fear River, 13 swine CAFOs and four poultry CAFOs, traditional agriculture, about 6% wetland coverage. ______________________________________________________________________ 53 Table 3.2. Lower Cape Fear River Program sampling sites included in the 20-year trend analysis for nutrients, fecal coliform bacteria (FC) and chlorophyll a. + = significant increase, - = significant decrease. Only significant increases or decreases demonstrated by two or three statistical tests are presented. Note that the estuarine sites (BRR-M18) were not included in the fecal coliform analysis because fecal coliform sampling was ceased at those sites in 2011 and Enterococcus sampling was initiated. ______________________________________________________________________ Ammonium Nitrate TN OP TP FC ______________________________________________________________________ Cape Fear River mainstem sites NC11 - + AC - + DP - + IC - + NAV - HB - + BRR - M61 - M54 - M35 + M23 + M18 + BRN + + - + HAM + + Black River watershed sites SR + - + COL + + + + + 6RC + + + + + GCO - + + + + LCO + + + B210 + + + + + Northeast Cape Fear River watershed sites NC403 + + + - + PB + + ANC + + + + GS - SAR - - + ROC + + + LRC + + + + + NCF117 + + + NCF6 + + 54 Figure 3.1. Long term nitrate trends for several key sampling sites in the lower Cape Fear River watershed, presented as annual medians, significant as p < 0.05 (Colly Creek non-significant). 0 200 400 600 800 1,000 1,200 1,400 2000 2005 2010 2015 2020 Median Annual Nitrate Values 2000-2019, Six Runs Creek 0 100 200 300 400 500 600 700 2000 2005 2010 2015 2020 Median Annual Nitrate Values 2000-2029, Great Coharie Creek 0 100 200 300 400 500 600 700 2000 2005 2010 2015 2020 Median Annual Nitrate Values 2000-2019, Little Coharie Creek 0 50 100 150 200 250 2000 2005 2010 2015 2020 Median Annual Nitrate Values,2000-2029, Angola Creek 0 100 200 300 400 2000 2005 2010 2015 2020 Median Annual Nitrate values, 2000-2019, B210,5th Order Collector River 0 500 1,000 1,500 2,000 1995 2000 2005 2010 2015 2020 Median Annual Nitrate Values, 2000-2019, NC403, 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2000 2005 2010 2015 2020 Median Annual Nitrate Values, 2000-2019, Rockfish Creek 0 50 100 150 200 2000 2005 2010 2015 2020 Median Annual Nitrate Values, 2000 -2019, Colly Creek 55 Figure 3.2. Long term total nitrogen (TN) trends for several key sampling sites in the lower Cape fear watershed, presented as annual medians, 2000 – 2019, significant at p < 0.05. 0 500 1,000 1,500 2,000 2,500 3,000 3,500 2000 2005 2010 2015 2020 Median TN Values, 2000 -2019, Rockfish Creek 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2000 2005 2010 2015 2020 Median TN Values, 200 -2019, Great Coharie Creek 0 500 1,000 1,500 2,000 2,500 3,000 2000 2005 2010 2015 2020 Median TN Values, 2000 -2019, Station NC403 0 500 1,000 1,500 2,000 2,500 2000 2005 2010 2015 2020 Median TN Values, 2000 -2019, Six Runs Creek 0 200 400 600 800 1,000 1,200 1,400 1,600 2000 2005 2010 2015 2020 Median Annual TN Values, 2000 -2019, B210, 5th Order Collector River 0 200 400 600 800 1,000 1,200 1,400 1,600 2000 2005 2010 2015 2020 Median Total Nitrogen Values, 2000 -2019, Browns Creek 56 Figure 3.3. Long term total phosphorus (TP) trends for several key sampling sites in the lower Cape fear River basin, presented as annual medians, 2000-2019, significant at p < 0.05. 0 50 100 150 200 250 300 350 400 450 2000 2005 2010 2015 2020 Median Annual Total TP Values, 2000 -2019, Great Coharie Creek 0 20 40 60 80 100 120 140 160 180 2000 2005 2010 2015 2020 Median Annual TP Values, 2000-2019, Little Coharie Creek 0 50 100 150 200 250 2000 2005 2010 2015 2020 Median Annual TP Valuess, 2000 -2019, Six Runs Creek 0 50 100 150 200 250 2000 2005 2010 2015 2020 Median Annual TP Values, 2000 -2019, B210, 5th Order Collector River 0 50 100 150 200 250 300 2000 2005 2010 2015 2020 Median Annual TP values, 2000 -2019, Angola Creek 0 20 40 60 80 100 120 140 160 2000 2005 2010 2015 2020 Median Annual TP Values, 2000 -2019, NCF117, 5th Order Collector River 57 Figure 3.4. Long term fecal coliform bacteria count trends at key sampling sites in the lower Cape Fear River watershed, presented as annual medians, significant at p < 0.05. 0 50 100 150 200 250 300 2000 2005 2010 2015 2020 Median Annual Fecal Coliform Counts, 2000 -2019, Six Runs Creek 0 50 100 150 200 250 300 350 400 2000 2005 2010 2015 2020 Median Annual Fecal Coliform Counts, 2000 -2019, Little Coharie Creek 0 50 100 150 200 250 2000 2005 2010 2015 2020 Medain Annual Fecal Coliform Counts, 2000 -2019, Great Coharie Creek 0 100 200 300 400 500 600 700 800 900 1,000 2000 2005 2010 2015 2020 Median Annual Fecal Coliform Counts, 2000 -2019, Rockfish Creek 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2000 2005 2010 2015 2020 Median Annual Fecal Coliform Counts, 2000-2019, Brown's Creek 0 50 100 150 200 250 300 350 400 450 2000 2005 2010 2015 2020 Medain Annual Fecal Coliform Counts, 200 -2019, NC403 58