Lower Cape Fear River Program 2019 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2019
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
November 2020
CMS Report No. 20-02
Center for Marine Science
University of North Carolina Wilmington
Wilmington, N.C. 28409
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 2019. 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. 2001). 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, than 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
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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. Legal actions were initiated against the company from NC Attorney General, NCDEQ and Cape Fear River Watch 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 2019 – Hurricane Dorian impacted
southeastern North Carolina September 5th with rain and tornadoes, and made landfall at Cape Hatteras September 6th. The hurricane had some impact on system dissolved oxygen (DO) but it was relatively short-lived and relegated to selected sites only, i.e. the impacts were far more mild than those of Hurricane Florence in 2018.
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.
As noted, DO concentrations in the tributary streams were briefly impacted by the
hurricane, but some are chronically bad year-after-year. In 2019 ANC was below standard 27% of the time sampled, but all of the other stream stations were below standard less than 25% of the time. Considering all sites sampled in 2019, we rated 16% as poor for dissolved oxygen, 34% as fair, and 50% as good.
Annual mean turbidity levels for 2019 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 exceeded the estuarine turbidity standard only in April on our sampling trips. 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 2019. Average chlorophyll a concentrations across most sites were low in 2019. The standard
of 40 µg/L was exceeded once each at Station M54, SR, GS and PB, and there were several smaller algal blooms as well. We note the highest chlorophyll a levels in the river and estuary typically occur late spring to late-summer. Nuisance cyanobacterial
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blooms did not occur in the river and upper estuary in 2019. For the 2019 period UNCW rated 100% of the stations as good in terms of chlorophyll a.
Fecal bacteria counts in the estuary and at many of the stream stations were elevated in
2019. Sites with the highest counts in general were BRN, PB, HAM, SAR and LRC. However, the main river and estuary sites were generally in good condition in 2019. For bacterial water quality overall, 10% of the sites rated as poor, 32% as fair, and 58% as good, an improvement from 2018.
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 and PB, and non-point locations ROC, 6RC, and GCO.
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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…....……..……….........................................................…..17 Biological Parameters.......……….....……......................................................…..20
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1.0 Introduction
Michael A. Mallin
Aquatic Ecology Laboratory Center for Marine Science University of North Carolina Wilmington
The Lower Cape Fear River Program 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 2019.
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
25-year (1995-2019) 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 UNCW Biology Department and includes the benefit of additional data collected by the
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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.
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 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
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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/
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.
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Table 1.1 Description of sampling locations for the Lower Cape Fear River Program, 2019.
Collected by Boat
AEL Station DWR Station #Description Comments County LatLon 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
M61B9800000 Cape Fear River at Channel Marker 61 at Wilmington Downstream of several point source discharges New Hanover 34.1938-77.9573 SC 03030005
M54B9795000 Cape Fear River at Channel Marker
54
Downstream of several point source
discharges New Hanover 34.1393-77.946 SC 03030005
M35B9850100 Cape Fear River at Channel Marker 35 Upstream of Carolina Beach discharge Brunswick 34.0335-77.937 SC 03030005
M23B9910000 Cape Fear River at Channel Marker
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Downstream of Carolina Beach
discharge Brunswick 33.9456-77.9696 SA HQW 03030005
M18B9921000 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 CooperDownstream 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
B210B9000000 Black River at NC 210 at Still Bluff 1st bridge upstream of Cape Fear River Pender 34.4312-78.1441 C Sw ORW+03030006
NC403B9090000 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 WallaceUpstream 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 HillDWR 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
NCF117B9580000 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
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Figure 1.1. Map of the Lower Cape Fear River system and the LCFRP sampling stations.
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2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River and Estuary
Michael A. Mallin and Matthew R. McIver
Aquatic Ecology Laboratory Center for Marine Science University of North Carolina Wilmington
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 2019 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
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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 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 ca. 0.1 m below the surface in triplicate in amber 125 mL Nalgene plastic bottles and placed on ice. In the laboratory 50 mL 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).
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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, 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. 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-2000 Yes
Specific Conductivity SM 2510 B-1997 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
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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
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 2019. 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. As noted, the Cape Fear region experienced some impacts from Hurricane Dorian in 2019; therefore this report reflects its
impacts in fall.
Physical Parameters Water temperature
Water temperatures at all stations ranged from 2.9 to 32.1oC, and individual station annual averages ranged from 16.7 to 20.5oC (Table 2.1). Highest temperatures occurred during July and lowest temperatures during January and February. 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 34.7 practical salinity units (psu) and station annual means ranged from 1.5 to 24.4 psu (Table 2.2). Lowest salinities occurred in late winter and spring of 2019 and again in September following the heavy rains from Hurricane Dorian. The annual mean salinities for 2019 were approximately the same compared with the twenty-two year average for 1995-2018 (Figure 2.1). Two stream stations, NC403 and PB,
had occasional oligohaline conditions due to discharges from pickle production facilities.
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SC-CH is a blackwater tidal creek that enters the Northeast Cape Fear River just upstream of Wilmington and salinity there ranged from 0.1 to 2.4 psu.
Conductivity
Conductivity at the estuarine stations ranged from 0.07 to 52.83 mS/cm and from 0.05 to 4.85 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
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 3.3 to 8.4 and station annual means ranged from 3.9 (at COL) to 8.4 (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 2019 ranged from 0.8 to 13.4 mg/L and station annual means ranged from 5.9 to 10.1 mg/L (Table 2.5). Overall, average dissolved oxygen levels for 2019 were slightly lower compared with the long-term average (Fig. 2.2). River dissolved oxygen levels were low during the summer and early fall (Table 2.5), often
falling below the state standard of 5.0 mg/L at several river and upper estuary stations.
While DO concentrations were already low in summer the September arrival of Hurricane Dorian in September brought additional rainfall to the area. This caused increased BOD loading from animal waste, sewage and natural swamp organic matter which decreased
DO lower than usual in September and October. However, the decrease in DO was
relatively minor and short lived – with DO recovered by November, and relegated to
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selected stations only (Table 2.5); i.e. very minor compared with 2018’s Hurricane Florence.
NAV, HB and BRR were below 5.0 mg/L on 33% or more of occasions sampled, and IC
was below 5.0 mg/L on 42% of occasions. Based on number of occasions the river stations were below 5 mg/L dissolved oxygen UNCW rated NAV, HB, IC and BRR as poor for 2019; the lower 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. DO conditions in the lower river and estuary in 2019 were better than 2018.
Most tributary Stations were rated Fair or good in 2019, except ANC, rated Poor (Table 2.5). Some hypoxia can be attributed to low summer water conditions and some
potentially to CAFO runoff; however point-source discharges also likely contribute to low
dissolved oxygen levels at NC403 and possibly SR, especially via nutrient loading (Mallin et al. 2001; 2002; 2004). Hypoxia is thus a continuing problem, with 50% of the sites impacted in 2019.
Field Turbidity
Field turbidity levels ranged from 0 to 36 Nephelometric turbidity units (NTU) and station annual means ranged from 2 to 12 NTU (Table 2.6). The State standard for estuarine turbidity is 25 NTU. Highest mean turbidities were at NC11-DP (11-12 NTU), with
turbidities generally low in the middle to lower estuary (Figure 2.3). The estuarine stations
did not exceed the estuarine turbidity standard on our 2019 sampling trips. As in the previous year, mean turbidity levels for 2019 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. The State standard for freshwater turbidity is 50
NTU. Note: In addition to the laboratory-analyzed turbidity that are required by NCDWQ 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.
15
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 33.3 mg/L with station annual means from 1.7 to 16.7 mg/L (Table 2.7). The overall highest river values were at DP and AC. 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, 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 only two occasions in the 2019 data). 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 The attenuation of solar irradiance through the water column is measured by a logarithmic
function (k) per meter. The higher this light attenuation coefficient is the more strongly light
is attenuated (reduced through absorbance or reflection) in the water column. Due to persistent instrumentation issues light attenuation data were not collected in the latter half of 2019. Based on limited data, river and estuary light attenuation coefficients ranged from 2.00 to 5.43/m and station annual means ranged from 2.42 at DP to 4.38 at NAV (Table
2.8). Elevated mean and median light attenuation occurred from NC11 river downstream
to M54 in the estuary (Table 2.8). In the Cape Fear system, light is attenuated by both turbidity and water color. High light attenuation does not always coincide with high turbidity. Blackwater, though low
in turbidity, will attenuate light through absorption of solar irradiance. At NCF6 and BBT, blackwater stations with moderate turbidity levels, light attenuation was high. Compared to other North Carolina estuaries the Cape Fear has generally high light attenuation. The high average light attenuation is a major reason why phytoplankton production in the major rivers and the estuary of the LCFR is generally low. Whether caused by turbidity or water
16
color this attenuation tends to limit light availability to the phytoplankton (Mallin et al. 1999; 2004; Dubbs and Whalen 2008).
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 9,890 µg/L (at ROC) and station annual
means ranged from 660 to 3,758 µg/L (at ROC; Table 2.9). 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 and relatively similar
between NC11 and AC, 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 3,225 µg/L; other sites with elevated TN
were NC403, PB, COL, 6RC and GCO.
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 8,090 µg/L (at PB) and station annual means ranged from 33 to 2,350 µg/L (at ROC; Table 2.10). The highest average riverine nitrate levels were at NC11 through IC (583-496
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 = 290 µg/L) and the
Black River (B210 = 396 µg/L). Lowest river nitrate occurred during September and
October. In general, average concentrations in 2019 for the mainstem river were lower
than those of the average from 1995-2018 (Fig. 2.4).
Several stream stations showed high levels of nitrate on occasion including NC403, PB, ROC and 6RC. ROC and 6RC primarily receive non-point agricultural or animal waste drainage, while point sources contribute to NC403 and PB. 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. 1998; Mallin
17
et al. 2001; Mallin et al. 2002, Mallin et al. 2004). Thus, we conservatively consider nitrate concentrations exceeding 500 µg-N/L in Cape Fear watershed streams to be potentially problematic to the stream’s environmental health.
Ammonium/ammonia
Ammonium concentrations ranged from 10 (detection limit) to 2,390 µg/L and station
annual means ranged from 45 to 543 µg/L (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 M23 in the lower estuary just upstream of Southport. At the stream stations 2019 continued to be unusual in that Colly Creek (COL) showed multiple occasions of high ammonium, with particularly high concentrations in May
and June (Table 2.11). 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 (Fig. 2.6). 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). Thus, possibly ammonium-rich drainage from this area has made its way down to
the COL station. Additional areas with periodic elevated ammonium in 2019 included 6RC, ANC, ROC and PB (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 4,800 µg/L (at COL) and station
annual means ranged from 529 to 1,875 µg/L (Table 2.12). 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.
Total Phosphorus
Total phosphorus (TP) concentrations ranged from 10 (detection limit) to 3,020 µg/L (at
ROC) and station annual means ranged from 139 to 958 µg/L (ROC; Table 2.13). For the
mainstem and upper estuary, average TP for 2019 was considerably higher than the 1995-
2018 average (Figure 2.6). 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
18
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. 1998; 2004). Streams periodically exceeding this critical
concentration included ROC, GCO and ANC; NC403 and PB also yielded some high values. Stations NC403 and PB are downstream of wastewater discharges, while ROC, GCO and ANC are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from 5 to 1,570 µg/L (at ROC) and station annual means ranged
from 12 to 492 µg/L (Table 2.14). 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, ANC and GCO had the highest stream station orthophosphate concentrations. All of those sites are in non-point source areas.
19
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
detection limits on all sampling occasions. Iron (Fe) concentrations were measurable but
not at harmful levels. M35 and M23 were 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. LCFRP has voluntarily collected
samples on 10 occasions using EPA Method 1669.
Biological Parameters Chlorophyll a
During this monitoring period, chlorophyll a was low in river and estuary locations (Table 2.15). The state standard was not exceeded in the river or estuary samples in 2019 except at M54 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 approached 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 175 µg/L, and station annual means
ranged from 1-21 µg/L, generally low because of high river discharge in 2019 (see below). 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). For the
20
growing season May-September, long-term (1995-2019) average monthly flow at Lock and Dam #1 was approximately 3,523 CFS; however, for cyanobacterial bloom years 2009-2012 the growing season average flow was 1,698 CFS (USGS data;
(http://nc.water.usgs.gov/realtime/real_time_cape_fear.html). For 2019, discharge in May-September was 2,964 CFS, much higher than the 2009-2012 average, and nuisance cyanobacterial blooms did not occur in the river and upper estuary in 2019. As noted, the blooms in 2009-2012 all occurred when average river discharge for May-
September was below 1,900 CFS. Algal bloom formation was probably suppressed by
elevated river flow in 2013-2014 and 2016-2019. Flow in 2015 was well within the range when blooms can occur, yet blooms did not occur in 2015. Clearly other factors are at work in bloom formation.
Phytoplankton blooms occasionally occur at the stream stations, with a few occurring at
various months in 2019 (Table 2.15). 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 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. 2001; 2002; 2004; 2006; 2015). A stream station bloom exceeding the state standard of 40 µg/L occurred on one occasion at Station GS (175 µg/L), SR (58 µg/L) and PB (52 µg/L), and lesser blooms occurred on occasion at PB, N403, ROC, ANC and GS (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 10,500 CFU/100 mL and station annual geometric means ranged from 9 to 235 CFU/100 mL (Table 2.17). The state
human contact standard (200 CFU/100 mL) was exceeded in the mainstem river on only
one occasion in 2019 (Table 2.17). During 2019 some stream stations showed elevated fecal coliform pollution levels. HAM and BRN exceeded 200 CFU/100 mL 50% of the time sampled and LRC 33% of the time sampled. Other stations had periodic elevated counts particularly August-October – September and October would have been influenced by
Hurricane Dorian. 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 were much lower in 2019 (Fig. 2.5). Overall, 2019 was comparatively better than previous years, despite Hurricane Dorian.
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
21
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 milliliter 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 2019 this standard was exceeded in the estuary samples once each at BRR, M23 and M54, and twice at M18. Geometric mean enterococcus counts for 2019 were lower than those of the 2012-2018 period for the lower Cape Fear Estuary (Fig. 2.8). Overall, elevated fecal coliform and Enterococcus counts are problematic in this system,
with 42% of the stations rated as Fair or Poor in 2018 (although that was an improvement
from 2018). 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. 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., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 1998. Effect of organic and
inorganic nutrient loading on photosynthetic and heterotrophic plankton communities in blackwater rivers. Report No. 315. Water Resources Research Institute of the University of North Carolina, Raleigh, N.C.
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., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001. Effect of nitrogen and
phosphorus loading on plankton in Coastal Plain blackwater streams. Journal of
Freshwater Ecology 16:455-466.
22
Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002. Seeking science-based nutrient standards for coastal blackwater stream systems. Report No. 341. Water
Resources Research Institute of the University of North Carolina, Raleigh, N.C.
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. 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
Table 2.1 Water temperature (oC) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 7.8 7.8 7.9 8.7 8.5 9.1 10.0 10.0 JAN 11.7 11.8 12.0 12.9 12.4 13.6
FEB 9.5 10.9 10.7 11.1 10.4 12.1 12.5 12.9 FEB 12.3 12.3 12.5 12.6 12.3 12.6
MAR 6.7 6.7 7.0 6.8 7.1 7.5 8.0 7.9 MAR 6.3 6.5 6.7 6.5 6.8 6.6
APR 19.3 19.9 19.6 20.2 20.2 20.2 20.4 19.6 APR 14.4 14.5 14.5 16.7 15.3 16.0
MAY 22.3 22.2 22.1 22.6 22.7 22.8 22.9 23.4 MAY 22.8 22.9 23.2 24.2 24.4 25.0
JUN 27.9 27.9 27.8 27.6 27.5 27.4 27.2 27.3 JUN 28.4 28.6 28.2 27.9 27.9 27.8
JUL 31.2 32.1 31.4 31.1 31.0 30.9 30.4 30.6 JUL 30.3 30.2 29.7 29.2 29.7 29.5
AUG 29.0 29.4 30.7 29.4 29.3 29.4 29.0 29.1 AUG 29.5 29.6 29.6 29.2 29.8 28.9
SEP 26.8 27.2 26.8 27.1 27.4 27.1 26.7 26.4 SEP 27.6 27.0 26.1 24.8 25.4 26.3
OCT 24.5 24.2 23.8 24.3 23.7 22.8 23.2 22.7 OCT 27.6 27.9 27.8 27.1 27.5 27.7
NOV 19.5 20.3 19.7 20.4 20.4 19.9 19.6 19.6 NOV 18.4 18.8 19.0 18.1 19.0 20.2
DEC 11.4 11.7 12.1 12.8 12.4 12.6 12.7 13.2 DEC 10.3 10.7 10.9 10.4 10.6 11.9
mean 19.7 20.0 20.0 20.2 20.1 20.2 20.2 20.2 mean 20.0 20.1 20.0 20.0 20.1 20.5
std dev 8.8 8.8 8.7 8.4 8.5 8.1 7.7 7.7 std dev 8.7 8.6 8.4 8.1 8.3 8.0
median 20.9 21.3 20.9 21.5 21.6 21.5 21.7 21.2 median 20.6 20.9 21.1 21.2 21.7 22.6
max 31.2 32.1 31.4 31.1 31.0 30.9 30.4 30.6 max 30.3 30.2 29.7 29.2 29.8 29.5
min 6.7 6.7 7.0 6.8 7.1 7.5 8.0 7.9 min 6.3 6.5 6.7 6.5 6.8 6.6
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 8.4 8.0 7.8 8.6 7.7 10.4 10.9 12.6 13.3 JAN 7.7 7.1 7.0 5.7 4.6 3.6 2.9 8.0 7.0
FEB 13.2 9.7 12.5 10.8 11.0 11.3 9.6 12.0 11.4 FEB 11.6 11.3 10.7 11.3 11.2 11.8 12.0 13.6 12.5
MAR 6.0 6.7 7.2 6.5 6.5 6.5 6.3 6.3 6.3 MAR 6.1 3.8 5.7 6.4 6.2 6.4 6.3 6.5 6.8
APR 21.9 21.3 23.6 22.8 24.0 21.5 20.8 20.4 22.0 APR 19.0 19.8 19.0 20.0 19.7 19.9 20.5 20.7 19.9
MAY 22.5 21.6 20.2 21.4 22.7 19.8 20.0 24.4 23.5 MAY 28.8 25.5 26.3 26.2 25.5 26.7 26.6 26.2 25.1
JUN 23.1 22.7 22.7 22.7 22.5 23.5 23.6 27.0 26.4 JUN 26.9 25.4 25.5 26.1 25.9 26.4 25.9 26.5 24.1
JUL 26.5 28.4 28.9 29.8 29.4 28.5 29.5 29.6 JUL 27.1 23.4 24.9 24.6 24.0 25.6 25.4 26.8 24.1
AUG 24.9 27.5 26.9 27.1 27.7 26.7 26.6 29.5 30.2 AUG 28.0 26.2 26.0 25.5 25.9 26.1 26.1 26.5 25.1
SEP 22.3 21.6 22.1 23.0 22.6 22.6 22.3 24.9 25.6 SEP 23.3 22.1 22.4 22.4 22.4 23.2 23.0 23.8 22.3
OCT 27.4 25.6 24.3 26.2 27.4 26.7 24.8 26.3 27.3 OCT 18.6 16.8 17.2 18.6 18.5 18.4 17.9 16.7 15.0
NOV 7.0 7.2 7.6 6.9 8.6 8.4 14.5 15.1 NOV 10.4 9.7 10.5 11.3 11.1 10.7 9.8 11.1 10.6
DEC 10.2 9.0 8.9 9.9 8.7 9.0 11.2 11.1 11.7 DEC 11.9 12.5 10.9 12.4 12.5 13.0 12.2 13.2 12.3
mean 18.8 17.4 16.7 18.0 18.1 18.0 17.8 19.9 20.2 mean 18.3 17.0 17.2 17.5 17.3 17.7 17.4 18.3 17.1
std dev 7.8 8.6 7.9 8.5 9.1 8.3 7.9 8.1 8.2 std dev 8.5 7.9 7.9 7.8 7.8 8.3 8.4 7.7 7.1
median 22.3 21.5 20.2 22.1 22.6 20.7 20.4 22.4 22.8 median 18.8 18.3 18.1 19.3 19.1 19.2 19.2 18.7 17.5
max 27.4 28.4 26.9 28.9 29.8 29.4 28.5 29.5 30.2 max 28.8 26.2 26.3 26.2 25.9 26.7 26.6 26.8 25.1
min 6.0 6.7 7.2 6.5 6.5 6.5 6.3 6.3 6.3 min 6.1 3.8 5.7 5.7 4.6 3.6 2.9 6.5 6.8
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Table 2.2 Salinity (psu) 2019 at the Lower Cape Fear River Program estuarine stations.
NAV HB BRR M61 M54 M35 M23 M18 NCF6 SC-CH
JAN 0.0 0.0 0.0 1.4 1.6 3.6 10.7 11.6 0.0 0.1
FEB 0.1 0.6 0.1 1.5 4.0 10.0 15.1 28.9 0.1 1.1
MAR 0.0 0.0 0.1 2.8 3.9 6.6 13.7 16.4 0.1 0.1
APR 0.0 0.0 0.0 0.0 0.5 3.1 9.8 12.9 0.1 0.1
MAY 0.0 0.1 0.1 2.0 2.3 6.0 14.0 14.0 0.9 4.3
JUN 0.1 0.2 2.1 8.8 13.5 20.1 28.2 30.0 11.9 10.1
JUL 4.5 4.6 6.8 10.5 13.2 23.2 31.0 34.7 4.5 6.8
AUG 0.2 1.8 4.9 12.5 15.8 24.4 31.1 31.6 7.0 9.6
SEP 0.1 1.6 0.3 2.0 8.4 11.8 20.0 24.6 8.9 0.2
OCT 9.3 14.3 14.5 20.2 20.3 23.5 29.1 30.0 5.8 6.2
NOV 3.6 5.6 10.1 14.9 16.4 20.7 27.4 28.2 2.2 15.2
DEC 0.1 0.3 2.1 6.4 9.1 15.5 22.4 29.7 0.1 2.7
mean 1.5 2.4 3.4 6.9 9.1 14.0 21.0 24.4 3.5 4.7
std dev 2.9 4.2 4.8 6.5 6.7 8.2 8.2 8.3 4.1 5.0
median 0.1 0.5 1.2 4.6 8.8 13.7 21.2 28.6 1.6 3.5
max 9.3 14.3 14.5 20.2 20.3 24.4 31.1 34.7 11.9 15.2
min 0.0 0.0 0.0 0.0 0.5 3.1 9.8 11.6 0.0 0.1
25
0
5
10
15
20
25
30
NAV HB BRR M61 M54 M35 M23 M18 NCF6 SC-CH
Sa
l
i
n
t
y
(
P
S
U
)
Figure 2.1 Salinity at the Lower Cape Fear River Program estuarine stations1995-2018 versus 2019.
1995-2018
2019
26
Table 2.3 Conductivity (mS/cm) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 0.09 0.09 0.09 2.62 3.06 6.59 18.13 19.51 JAN 0.07 0.07 0.07 0.07 0.07 0.09
FEB 0.11 1.22 2.81 2.82 7.23 16.89 24.85 44.71 FEB 0.08 0.09 0.10 0.09 0.10 0.11
MAR 0.09 0.09 0.10 5.25 7.08 11.51 22.63 26.64 MAR 0.09 0.09 0.09 0.08 0.09 0.12
APR 0.07 0.08 0.07 0.09 0.95 5.71 16.61 21.46 APR 0.09 0.11 0.11 0.09 0.10 0.14
MAY 0.09 0.10 0.10 3.75 4.24 10.07 23.70 23.33 MAY 0.10 0.11 0.11 0.10 0.11 1.73
JUN 0.24 0.33 4.07 15.18 22.48 32.33 43.75 46.19 JUN 0.11 0.13 0.23 0.21 0.26 19.94
JUL 8.17 8.50 12.07 18.00 22.09 36.96 47.80 52.83 JUL 0.12 0.28 0.21 0.16 0.20 8.17
AUG 0.48 3.45 8.83 21.00 26.03 38.62 47.92 48.86 AUG 0.11 0.12 0.18 0.15 0.16 12.23
SEP 0.13 3.15 0.59 3.87 14.27 19.90 32.16 38.60 SEP 0.12 0.23 0.18 0.12 0.15 15.36
OCT 15.94 23.55 23.93 32.36 32.45 37.13 45.08 46.30 OCT 0.13 0.14 0.21 0.15 0.19 10.22
NOV 6.45 9.86 17.04 23.56 26.80 32.98 42.48 43.68 NOV 0.15 0.18 0.19 0.16 0.21 4.15
DEC 0.17 0.68 3.88 11.27 15.47 25.45 35.59 45.77 DEC 0.14 0.22 0.17 0.13 0.17 0.28
mean 2.67 4.26 6.13 11.65 15.18 22.85 33.39 38.16 mean 0.11 0.15 0.15 0.13 0.15 6.04
std dev 5.02 6.94 7.84 10.30 10.66 12.59 11.87 11.95 std dev 0.02 0.06 0.06 0.04 0.06 6.98
median 0.15 0.95 3.35 8.26 14.87 22.68 33.88 44.19 median 0.11 0.12 0.18 0.12 0.15 2.94
max 15.94 23.55 23.93 32.36 32.45 38.62 47.92 52.83 max 0.15 0.28 0.23 0.21 0.26 19.94
min 0.07 0.08 0.07 0.09 0.95 5.71 16.61 19.51 min 0.07 0.07 0.07 0.07 0.07 0.09
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 0.07 0.13 0.13 0.28 0.47 0.10 0.12 0.10 0.11 JAN 0.09 0.05 0.06 0.13 0.10 0.11 0.07 0.11 0.12
FEB 0.08 0.14 0.13 0.34 0.43 0.11 0.13 0.13 2.18 FEB 0.09 0.05 0.06 0.13 0.09 0.11 0.07 0.12 0.14
MAR 0.10 0.13 0.12 0.29 0.36 0.10 0.10 0.12 0.16 MAR 0.09 0.05 0.06 0.12 0.09 0.13 0.07 0.12 0.16
APR 0.08 0.15 0.14 0.43 0.60 0.10 0.12 0.11 0.18 APR 0.08 0.05 0.06 0.12 0.09 0.12 0.07 0.10 0.12
MAY 0.11 0.21 0.17 0.80 2.62 0.14 0.20 0.19 7.78 MAY 0.12 0.07 0.08 0.16 0.11 0.25 0.11 0.14 0.25
JUN 0.06 0.30 0.28 0.70 1.57 0.17 0.46 0.38 17.23 JUN 0.13 0.07 0.09 0.15 0.11 0.15 0.10 0.13 0.26
JUL 0.10 0.24 1.31 4.75 0.13 0.46 0.35 11.91 JUL 0.15 0.06 0.10 0.18 0.12 0.40 0.09 0.14 0.24
AUG 0.11 0.39 0.36 1.58 4.85 0.24 0.72 0.35 16.49 AUG 0.13 0.06 0.08 0.08 0.07 0.13 0.10 0.14 0.28
SEP 0.11 0.18 0.15 0.65 2.10 0.13 0.22 0.12 0.49 SEP 0.09 0.06 0.08 0.07 0.11 0.21 0.09 0.13 0.26
OCT 0.16 0.22 0.19 1.03 1.90 0.16 0.32 0.19 11.03 OCT 0.13 0.06 0.08 0.17 0.12 0.16 0.08 0.13 0.23
NOV 0.25 0.21 1.22 0.78 0.18 0.23 0.23 24.90 NOV 0.12 0.06 0.09 0.17 0.12 0.17 0.09 0.13 0.21
DEC 0.14 0.19 0.17 0.66 0.72 0.15 0.18 0.16 4.95 DEC 0.11 0.06 0.08 0.16 0.11 0.15 0.08 0.13 0.19
mean 0.10 0.21 0.19 0.77 1.76 0.14 0.27 0.20 8.12 mean 0.11 0.06 0.08 0.14 0.10 0.17 0.09 0.13 0.20
std dev 0.03 0.08 0.08 0.43 1.60 0.04 0.19 0.11 8.27 std dev 0.02 0.01 0.01 0.04 0.02 0.08 0.01 0.01 0.06
median 0.10 0.20 0.17 0.68 1.17 0.13 0.21 0.17 6.37 median 0.11 0.06 0.08 0.14 0.11 0.15 0.08 0.13 0.22
max 0.16 0.39 0.36 1.58 4.85 0.24 0.72 0.38 24.90 max 0.15 0.07 0.10 0.18 0.12 0.40 0.11 0.14 0.28
min 0.06 0.13 0.12 0.28 0.36 0.10 0.10 0.10 0.11 min 0.08 0.05 0.06 0.07 0.07 0.11 0.07 0.10 0.12
27
Table 2.4 pH 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 7.1 6.7 7.3 7.2 7.8 7.5 7.7 7.8 JAN 6.1 6.2 6.3 6.1 6.2 6.0
FEB 6.7 6.9 7.3 7.1 7.3 7.8 8.0 8.1 FEB 6.2 6.2 6.3 6.0 6.2 6.2
MAR 6.7 6.7 7.0 6.8 7.1 7.5 8.0 7.9 MAR 6.3 6.5 6.7 6.5 6.8 6.6
APR 6.6 6.6 6.7 6.7 6.9 7.2 7.9 7.9 APR 6.3 6.5 6.6 6.3 6.4 6.5
MAY 6.8 6.9 7.0 6.8 7.1 7.2 7.6 7.9 MAY 6.7 6.6 6.7 6.3 6.7 6.6
JUN 6.9 6.9 7.0 7.1 7.3 7.6 7.9 7.9 JUN 6.5 6.8 6.8 6.8 6.8 7.0
JUL 6.9 7.1 7.2 7.3 7.8 8.0 8.0 8.0 JUL 6.7 6.8 6.7 6.6 6.7 6.7
AUG 6.8 6.8 7.0 7.1 7.3 7.8 7.9 7.9 AUG 6.2 6.7 6.8 6.4 6.4 6.8
SEP 6.2 6.6 6.9 6.5 6.8 7.1 7.6 7.8 SEP 6.2 6.8 6.4 6.1 6.2 6.6
OCT 6.9 7.1 7.1 7.4 7.5 7.7 7.8 7.9 OCT 6.8 6.8 6.7 6.5 6.6 6.6
NOV 7.0 7.2 7.3 7.4 7.6 7.8 8.0 8.0 NOV 6.7 6.9 6.9 6.6 6.8 6.8
DEC 6.8 7.3 7.4 7.4 7.6 7.9 8.1 8.1 DEC 6.3 7.0 6.9 6.6 6.8 6.7
mean 6.8 6.9 7.1 7.1 7.3 7.6 7.9 7.9 mean 6.4 6.7 6.7 6.4 6.6 6.6
std dev 0.2 0.2 0.2 0.3 0.3 0.3 0.2 0.1 std dev 0.2 0.3 0.2 0.2 0.3 0.3
median 6.8 6.9 7.1 7.1 7.3 7.7 7.9 7.9 median 6.3 6.8 6.7 6.5 6.7 6.6
max 7.1 7.3 7.4 7.4 7.8 8.0 8.1 8.1 max 6.8 7.0 6.9 6.8 6.8 7.0
min 6.2 6.6 6.7 6.5 6.8 7.1 7.6 7.8 min 6.1 6.2 6.3 6.0 6.2 6.0
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 4.7 6.1 6.4 6.2 6.4 6.7 6.4 6.1 6.3 JAN 5.6 3.8 5.5 6.3 6.0 6.1 5.5 6.1 6.3
FEB 5.5 6.6 7.0 6.5 6.5 6.6 6.6 6.5 6.4 FEB 6.0 3.9 5.4 6.2 6.0 6.3 6.4 6.4 6.6
MAR 6.0 6.7 7.2 6.5 6.5 6.5 6.3 6.3 6.3 MAR 6.1 3.8 5.7 6.4 6.2 6.4 6.3 6.5 6.8
APR 5.7 6.7 6.9 6.5 6.6 6.8 6.6 6.3 6.5 APR 5.9 3.9 5.6 6.3 6.1 6.3 6.3 6.2 6.4
MAY 6.4 7.0 6.9 6.8 6.7 7.8 7.0 6.9 6.8 MAY 6.5 4.6 6.3 7.2 6.8 7.0 6.3 7.0 7.4
JUN 5.2 7.0 6.8 6.6 6.8 8.1 7.5 7.1 7.0 JUN 6.4 4.8 6.1 6.9 6.9 6.7 6.1 7.0 6.5
JUL 6.2 7.2 6.9 7.1 7.6 7.4 7.2 6.9 JUL 6.5 4.2 6.2 7.0 6.9 7.0 6.0 7.2 7.4
AUG 6.3 7.0 7.2 7.1 6.9 8.1 7.4 7.1 7.0 AUG 6.5 3.8 5.5 5.5 5.9 6.1 6.3 7.3 7.3
SEP 5.5 6.5 6.5 7.0 6.7 6.7 6.5 5.7 6.6 SEP 5.7 3.6 5.5 6.6 6.3 6.5 6.1 6.6 6.8
OCT 6.5 6.7 6.5 6.8 6.9 7.4 7.0 6.6 6.8 OCT 6.2 3.7 5.8 6.5 6.2 6.1 6.2 6.7 6.5
NOV 7.0 7.5 7.3 7.4 7.5 7.6 8.4 6.8 NOV 5.5 3.6 5.6 6.5 6.3 6.2 5.2 6.4 6.5
DEC 6.6 6.6 7.1 6.7 6.7 6.6 6.9 7.5 6.5 DEC 5.3 3.3 5.4 6.4 6.2 6.2 6.2 6.4 6.6
mean 5.9 6.8 6.9 6.7 6.8 7.2 6.9 6.8 6.7 mean 6.0 3.9 5.7 6.5 6.3 6.4 6.1 6.7 6.8
std dev 0.6 0.3 0.3 0.3 0.3 0.6 0.5 0.7 0.3 std dev 0.4 0.4 0.3 0.4 0.4 0.3 0.4 0.4 0.4
median 6.0 6.7 6.9 6.8 6.7 7.1 7.0 6.8 6.7 median 6.1 3.8 5.6 6.5 6.2 6.3 6.2 6.6 6.6
max 6.6 7.2 7.5 7.3 7.4 8.1 7.6 8.4 7.0 max 6.5 4.8 6.3 7.2 6.9 7.0 6.4 7.3 7.4
min 4.7 6.1 6.4 6.2 6.4 6.5 6.3 5.7 6.3 min 5.3 3.3 5.4 5.5 5.9 6.1 5.2 6.1 6.3
28
Table 2.5 Dissolved Oxygen (mg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 10.7 10.5 10.5 9.9 9.9 9.6 9.4 9.5 JAN 9.4 9.3 9.1 7.5 8.5 7.7
FEB 10.7 10.5 10.5 10.2 9.8 9.6 9.4 8.8 FEB 10.0 9.8 9.7 8.6 9.5 9.2
MAR 8.5 8.8 8.7 8.5 8.6 8.9 9.1 8.9 MAR 9.9 9.9 9.9 8.7 9.8 8.4
APR 5.8 5.9 5.9 5.7 5.8 6.8 7.9 7.7 APR 9.4 9.3 9.0 8.0 8.6 8.1
MAY 6.1 6.7 6.8 6.1 6.4 6.4 6.6 7.3 MAY 7.0 6.5 6.9 5.2 6.9 5.5
JUN 4.5 4.4 4.4 4.7 5.0 5.9 6.0 6.1 JUN 5.6 5.8 4.4 4.4 4.4 5.0
JUL 5.0 5.9 5.6 5.7 7.6 7.3 6.1 6.4 JUL 6.3 5.9 5.2 4.4 4.8 5.4
AUG 4.2 4.2 4.9 4.2 4.7 6.2 5.4 5.7 AUG 6.2 5.9 5.5 4.2 4.9 4.3
SEP 3.3 2.9 3.7 3.1 3.8 4.7 5.7 5.7 SEP 5.7 4.6 3.8 3.8 3.7 3.3
OCT 4.5 4.8 4.9 5.4 6.0 6.9 6.7 6.9 OCT 6.4 6.2 4.1 3.3 3.4 3.3
NOV 6.1 6.1 6.0 6.1 6.7 7.2 7.4 7.5 NOV 8.3 8.0 7.5 6.3 6.7 6.1
DEC 9.2 9.1 9.0 8.8 8.8 8.9 8.9 8.3 DEC 10.5 10.2 10.0 9.7 9.8 8.6
mean 6.6 6.7 6.7 6.5 6.9 7.4 7.4 7.4 mean 7.9 7.6 7.1 6.2 6.8 6.2
std dev 2.6 2.5 2.4 2.3 2.0 1.6 1.5 1.3 std dev 1.9 2.0 2.4 2.2 2.4 2.1
median 6.0 6.0 6.0 5.9 6.6 7.1 7.1 7.4 median 7.7 7.3 7.2 5.8 6.8 5.8
max 10.7 10.5 10.5 10.2 9.9 9.6 9.4 9.5 max 10.5 10.2 10.0 9.7 9.8 9.2
min 3.3 2.9 3.7 3.1 3.8 4.7 5.4 5.7 min 5.6 4.6 3.8 3.3 3.4 3.3
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 7.7 9.6 11.2 10.4 10.6 11.1 9.2 7.5 7.9 JAN 10.3 9.5 10.6 11.6 11.6 12.8 12.4 10.9 11.0
FEB 9.2 11.0 12.6 10.8 10.9 11.4 10.4 8.5 9.4 FEB 9.1 8.3 9.4 9.6 9.5 9.8 10.0 9.8 10.2
MAR 10.5 11.4 13.4 11.7 11.8 11.2 9.7 8.4 8.7 MAR 8.3 8.1 8.5 9.0 9.0 8.5 8.9 9.8 11.0
APR 6.9 6.1 7.9 6.4 6.1 8.2 6.6 5.0 5.5 APR 6.2 5.2 6.6 6.7 6.3 5.7 5.6 7.8 7.6
MAY 4.4 6.7 6.8 7.4 7.9 11.0 6.4 5.1 5.2 MAY 4.6 3.0 5.5 5.1 6.2 5.9 1.1 7.8 6.6
JUN 2.6 6.5 5.7 4.9 5.4 10.2 5.4 5.4 4.6 JUN 5.3 3.7 6.2 6.2 6.4 5.7 4.8 7.5 5.1
JUL 0.8 6.5 3.4 9.3 8.0 4.5 5.2 4.4 JUL 5.0 5.9 5.9 6.7 6.4 5.9 4.8 8.1 7.7
AUG 8.0 5.4 4.3 3.3 7.3 9.2 2.1 6.1 5.1 AUG 4.9 5.1 6.0 4.5 6.0 4.5 1.7 7.2 5.3
SEP 4.0 5.5 1.6 5.4 8.1 8.1 4.5 2.1 3.7 SEP 4.7 5.2 6.2 6.9 7.1 6.3 2.4 7.7 7.2
OCT 2.5 6.1 2.3 4.4 8.5 9.0 4.1 2.1 3.9 OCT 6.4 6.9 7.9 7.9 7.8 6.4 6.2 8.8 7.6
NOV 10.9 9.1 9.8 10.1 12.7 10.2 7.0 7.5 NOV 8.5 7.7 9.5 9.7 9.7 8.9 7.7 10.2 9.1
DEC 8.0 9.3 8.9 9.3 8.5 11.2 9.0 8.5 8.7 DEC 8.9 7.1 9.5 9.3 9.1 7.8 7.4 9.8 9.0
mean 5.9 7.9 7.6 7.3 8.7 10.1 6.8 5.9 6.2 mean 6.9 6.3 7.7 7.8 7.9 7.4 6.1 8.8 8.1
std dev 3.2 2.3 3.9 3.0 1.9 1.6 2.8 2.2 2.1 std dev 2.0 2.0 1.8 2.1 1.8 2.3 3.4 1.3 2.0
median 6.9 6.6 7.9 6.9 8.5 10.6 6.5 5.8 5.4 median 6.3 6.4 7.3 7.4 7.5 6.4 5.9 8.5 7.7
max 10.5 11.4 13.4 11.7 11.8 12.7 10.4 8.5 9.4 max 10.3 9.5 10.6 11.6 11.6 12.8 12.4 10.9 11.0
min 0.8 5.4 1.6 3.3 5.4 8.0 2.1 2.1 3.7 min 4.6 3.0 5.5 4.5 6.0 4.5 1.1 7.2 5.1
29
0
1
2
3
4
5
6
7
8
9
NC11 AC DP IC NAV HB BRR M61 M54 M35 M23 M18 NCF117 NCF6 B210 BBT
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
Figure 2.2 Dissolved Oxygen at the Lower Cape Fear River Program mainstem stations 1995-2018 versus 2019.
1995-2018
2019
30
Table 2.6 Field Turbidity (NTU) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 14 12 12 8 9 8 5 5 JAN 32 32 32 20 27 4
FEB 11 10 10 8 11 5 3 5 FEB 8 11 11 4 7 7
MAR 13 14 11 8 9 8 5 6 MAR 22 21 20 7 18 4
APR 33 33 28 19 28 14 7 6 APR 14 15 13 5 11 2
MAY 16 16 13 10 10 8 8 4 MAY 20 17 16 6 7 7
JUN 12 11 14 9 8 7 5 3 JUN 6 7 8 7 10 7
JUL 8 8 8 6 9 5 2 3 JUL 6 7 9 6 8 11
AUG 11 9 7 7 7 8 7 3 AUG 6 7 8 5 5 13
SEP 3 3 4 3 1 1 2 2 SEP 5 6 6 3 6 4
OCT 5 5 15 7 5 7 6 8 OCT 4 6 5 3 5 7
NOV 6 3 4 3 3 3 4 4 NOV 4 5 6 2 4 2
DEC 3 2 3 2 2 1 3 13 DEC 6 7 7 4 6 7
mean 11 11 11 8 9 6 5 5 mean 11 12 12 6 10 6
std dev 8 8 7 4 7 4 2 3 std dev 9 8 8 5 7 3
median 11 10 11 8 9 7 5 5 median 6 7 9 5 7 7
max 33 33 28 19 28 14 8 13 max 32 32 32 20 27 13
min 3 2 3 2 1 1 2 2 min 4 5 5 2 4 2
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 7 3 2 3 8 6 4 4 4 JAN 2 4 1 3 2 1 4 21 36
FEB 8 2 1 2 7 5 5 3 13 FEB 1 6 1 3 0 0 2 8 5
MAR 7 1 0 3 10 7 7 2 3 MAR 1 11 0 7 1 0 2 6 3
APR 6 6 2 3 7 5 7 4 5 APR 2 4 0 3 0 0 4 14 7
MAY 10 7 3 6 5 6 7 3 12 MAY 3 6 2 3 3 4 17 5 8
JUN 9 11 5 3 4 4 6 3 14 JUN 2 7 2 3 3 4 3 4 25
JUL 7 5 4 13 2 6 3 8 JUL 2 2 2 3 2 3 4 3 5
AUG 7 1 3 3 16 4 6 1 14 AUG 4 2 3 4 4 4 17 4 8
SEP 2 5 7 1 10 6 9 2 7 SEP 2 0 2 3 2 3 2 3 3
OCT 2 2 30 0 5 2 5 3 9 OCT 2 1 3 5 2 2 2 5 3
NOV 0 0 1 4 2 3 3 11 NOV 1 1 1 0 0 0 1 4 2
DEC 3 0 1 2 2 2 1 3 8 DEC 1 1 1 2 1 0 1 10 3
mean 6 4 5 3 8 4 6 3 9 mean 2 4 2 3 2 2 5 7 9
std dev 3 3 9 2 4 2 2 1 4 std dev 1 3 1 2 1 2 6 5 11
median 7 3 2 3 7 5 6 3 9 median 2 3 2 3 2 2 3 5 5
max 10 11 30 6 16 7 9 4 14 max 4 11 3 7 4 4 17 21 36
min 2 0 0 0 2 2 1 1 3 min 1 0 0 0 0 0 1 3 2
31
0
5
10
15
20
25
NC11 AC DP IC NAV HB BRR M61 M54 M35 M23 M18 NCF117 NCF6 B210 BBT
Fi
e
l
d
T
u
r
b
i
d
i
t
y
(
N
T
U
)
Figure 2.3 Field Turbidity at the Lower Cape Fear River Program mainstem stations, 1995-2018 versus 2019.
1995-2018
2019
32
Table 2.7 Total Suspended Solids (mg/L) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 14.7 10.6 9.8 6.8 7.6 7.7 7.5 6.7 JAN 20.2 21.8 23.4 18.2 3.5
FEB 10.8 9.6 8.3 8.4 15.2 10.7 8.5 17.9 FEB 8.8 10.4 10.8 6.0 7.7
MAR 8.3 6.9 6.0 8.7 9.8 12.5 12.1 17.6 MAR 22.5 22.8 22.0 19.0 5.4
APR 22.4 18.2 19.3 16.3 33.3 19.6 14.1 12.9 APR 15.6 16.9 14.7 11.0 5.9
MAY 20.2 15.7 14.0 11.0 11.9 11.0 8.8 10.5 MAY 17.9 22.2 20.2 7.3 9.1
JUN 8.9 10.3 14.1 14.1 16.7 16.5 19.4 19.3 JUN 3.2 7.0 5.1 8.0 17.9
JUL 14.2 12.9 14.3 14.7 23.0 17.7 12.8 17.9 JUL 4.2 3.6 5.5 9.7 21.1
AUG 10.3 10.8 12.6 16.1 17.0 19.9 22.7 13.8 AUG 4.7 5.9 9.4 5.6 26.6
SEP 6.3 5.8 5.0 6.1 6.9 7.7 10.8 16.7 SEP 1.3 4.3 5.9 10.3 6.9
OCT 12.7 11.9 15.1 17.8 16.6 21.9 22.6 24.2 OCT 4.0 5.5 3.1 4.1 15.5
NOV 9.5 5.0 8.3 13.6 11.0 11.4 17.0 16.0 NOV 2.7 4.6 4.7 1.3 3.8
DEC 3.3 2.8 4.0 5.1 6.5 8.1 12.2 26.7 DEC 3.6 4.3 5.3 6.0 7.4
mean 11.8 10.0 10.9 11.6 14.6 13.7 14.0 16.7 mean 9.1 10.8 10.8 8.9 8.9
std dev 5.5 4.4 4.7 4.4 7.7 5.1 5.3 5.5 std dev 7.7 7.8 7.4 5.3 5.3
median 10.6 10.5 11.2 12.3 13.6 12.0 12.5 17.2 median 4.5 6.5 7.7 8.0 7.7
max 22.4 18.2 19.3 17.8 33.3 21.9 22.7 26.7 max 22.5 22.8 23.4 4.4 19.0
min 3.3 2.8 4.0 5.1 6.5 7.7 7.5 6.7 min 1.3 3.6 3.1 6.6 1.3
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 1.3 1.3 5.1 3.3 3.3 3.2 5.3 JAN 1.4 1.4
FEB 3.1 2.6 4.5 5.4 4.3 2.7 18.8 FEB 1.3 1.3
MAR 1.3 2.7 4.7 5.6 5.1 7.2 1.3 MAR 1.3
APR 6.5 4.0 5.1 2.8 6.7 3.3 5.2 APR 3.5 2.7
MAY 8.5 3.6 3.9 1.3 1.4 2.9 19.1 MAY 1.3 2.6
JUN 15.8 4.8 5.6 3.0 7.3 3.3 23.7 JUN 1.3 4.4
JUL 4.9 4.4 8.4 6.2 5.4 3.9 17.0 JUL 1.4 1.3
AUG 1.4 5.2 9.6 6.4 1.3 1.4 24.0 AUG 4.2 7.1
SEP 5.7 1.3 10.6 1.3 2.9 5.4 15.7 SEP 1.3 3.7
OCT 3.7 3.4 8.2 6.7 3.6 32.6 20.6 OCT 1.3 2.9
NOV 1.4 1.3 3.1 1.3 1.3 5.1 21.4 NOV 1.3 1.3
DEC 1.3 1.3 1.3 1.3 1.3 4.0 15.3 DEC 1.3 1.3
mean 4.6 3.0 5.8 3.7 3.7 6.3 15.6 mean 1.7 2.7
std dev 4.3 1.5 2.8 2.2 2.1 8.4 7.6 std dev 1.0 1.8
median 3.4 3.1 5.1 3.2 3.5 3.6 17.9 median 1.3 2.6
max 15.8 5.2 10.6 6.7 7.3 32.6 24.0 max 4.2 7.1
min 1.3 1.3 1.3 1.3 1.3 1.4 1.3 min 1.3 1.3
33
Table 2.8 Light Attenuation (k) 2019 at the Lower Cape Fear River Program stations8
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN JAN
FEB FEB 2.39 2.73 2.32 3.19 2.74 3.64
MAR MAR 3.05 3.15 2.08 3.04 3.03 3.36
APR 4.74 4.79 4.26 4.31 5.43 3.83 APR 3.52 2.96 2.75 3.39 2.93 3.30
MAY 4.01 3.27 2.88 3.18 3.06 2.53 2.24 2.61 MAY 2.51 2.66 2.52 4.12 2.00 2.71
JUN JUN
JUL JUL
AUG AUG
SEP SEP
OCT OCT
NOV NOV
DEC DEC
mean 4.38 4.03 3.57 3.75 4.25 3.18 2.24 2.61 mean 2.87 2.88 2.42 3.44 2.68 3.25
std dev 0.52 1.07 0.98 0.80 1.68 0.92 std dev 0.52 0.22 0.29 0.48 0.47 0.39
max 4.74 4.79 4.26 4.31 5.43 3.83 2.24 2.61 max 3.52 3.15 2.75 4.12 3.03 3.64
min 4.01 3.27 2.88 3.18 3.06 2.53 2.24 2.61 min 2.39 2.66 2.08 3.04 2.00 2.71
34
Table 2.9 Total Nitrogen (µg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 460 560 460 590 480 720 1,020 960 JAN 570 1,170 570 860 1,020
FEB 1,140 1,050 550 1,090 1,140 430 310 50 FEB 1,170 1,220 1,320 1,260 2,220
MAR 1,140 1,190 970 950 1,030 860 530 480 MAR 1,090 980 660 1,030 1,150
APR 1,310 1,100 1,130 1,030 1,280 1,050 580 540 APR 1,120 810 910 2,430 850
MAY 1,220 1,180 1,080 1,330 1,230 1,070 900 1,050 MAY 900 1,380 930 1,120 1,090
JUN 1,540 1,370 1,120 1,490 2,340 1,890 950 1,330 JUN 1,590 2,030 1,230 2,000 1,520
JUL 1,340 880 1,030 1,200 850 600 50 50 JUL 700 1,000 1,570 1,460 1,100
AUG 760 720 630 500 410 140 50 200 AUG 560 960 290 250 300
SEP 1,300 800 1,000 1,100 850 860 800 600 SEP 2,390 860 1,220 930 1,040
OCT 760 600 500 830 600 700 600 500 OCT 970 960 1,150 960 1,000
NOV 960 760 1,150 1,300 1,000 720 1,390 780 NOV 1,730 2,110 2,310 1,660 1,330
DEC 1,460 4,220 1,300 1,160 1,520 1,190 980 1,380 DEC 1,690 1,610 2,090 2,950 1,030
mean 1,116 1,203 910 1,048 1,061 853 680 660 mean 1,207 1,258 1,188 1,409 1,138
std dev 322 983 292 293 522 435 406 453 std dev 548 442 592 748 447
median 1,180 965 1,015 1,095 1,015 790 700 570 median 1,105 1,085 1,185 1,190 1,065
max 1,540 4,220 1,300 1,490 2,340 1,890 1,390 1,380 max 2,390 2,110 2,310 2,950 2,220
min 460 560 460 500 410 140 50 50 min 560 810 290 250 300
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 900 1,140 1,040 4,320 4,360 830 1,390 910 520 JAN 1,640 1,240 950 2,760 2,840 2,120 930 2,080 1,620
FEB 1,720 1,840 1,260 4,280 4,260 1,180 1,970 1,380 1,320 FEB 1,430 1,620 880 2,380 2,080 1,650 1,080 1,620 1,320
MAR 1,640 1,670 1,780 4,840 4,860 1,360 1,890 1,310 1,300 MAR 1,240 900 760 2,100 1,610 970 430 1,090 820
APR 1,860 1,240 940 3,590 3,350 1,550 3,700 1,670 1,250 APR 1,440 1,100 1,290 1,910 1,380 1,310 2,230 1,210 1,680
MAY 1,650 1,240 650 1,530 1,000 1,170 5,180 1,340 1,430 MAY 1,300 5,020 1,310 1,600 1,400 3,000 1,950 1,440 520
JUN 2,500 2,430 1,920 4,490 2,300 2,370 9,890 1,430 2,140 JUN 1,640 3,140 1,990 2,280 1,840 1,300 1,290 1,700 930
JUL 1,600 1,520 1,280 1,640 1,080 2,440 980 800 JUL 350 400 630 640 640 2,240 440 180 300
AUG 500 490 400 1,090 300 430 5,920 200 1,670 AUG 1,530 2,400 1,980 1,960 1,500 2,920 1,760 1,410 540
SEP 1,800 1,350 1,300 1,130 1,390 1,200 2,090 1,500 1,000 SEP 1,260 1,600 1,930 2,020 1,550 2,200 1,400 1,040 380
OCT 1,600 1,220 1,800 1,090 1,200 1,700 3,600 1,230 830 OCT 700 1,300 800 920 800 800 900 800 700
NOV 460 50 1,370 400 310 4,180 640 3,220 NOV 1,120 3,800 1,250 2,240 1,890 1,490 800 600 2,360
DEC 1,790 1,220 600 2,700 3,040 1,190 2,850 1,370 1,490 DEC 490 300 340 1,520 570 830 120 1,510 1,700
mean 1,596 1,318 1,067 2,643 2,342 1,198 3,758 1,163 1,414 mean 1,178 1,902 1,176 1,861 1,508 1,736 1,111 1,223 1,073
std dev 517 536 613 1,551 1,597 548 2,377 414 713 std dev 437 1,432 553 607 642 759 644 521 652
median 1,650 1,240 1,040 2,115 1,970 1,185 3,225 1,325 1,310 median 1,280 1,450 1,100 1,990 1,525 1,570 1,005 1,310 875
max 2,500 2,430 1,920 4,840 4,860 2,370 9,890 1,670 3,220 max 1,640 5,020 1,990 2,760 2,840 3,000 2,230 2,080 2,360
min 500 460 50 1,090 300 310 1,390 200 520 min 350 300 340 640 570 800 120 180 300
35
Table 2.10 Nitrate/Nitrite (µg/l) 2019 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 460 560 460 590 480 420 320 260 JAN 570 570 570 560 520
FEB 540 550 550 590 540 430 310 60 FEB 770 720 720 760 620
MAR 640 590 570 450 430 360 230 180 MAR 390 380 60 430 450
APR 310 300 330 330 380 350 280 240 APR 420 410 410 1,630 350
MAY 420 480 480 430 430 370 300 250 MAY 400 380 430 420 390
JUN 840 870 720 490 340 190 50 30 JUN 1,290 1,430 1,130 1,000 320
JUL 340 180 130 500 50 10 10 10 JUL 10 10 470 460 10
AUG 560 520 430 300 210 40 10 10 AUG 260 660 90 50 10
SEP 10 10 10 10 50 60 10 10 SEP 990 160 420 30 40
OCT 60 10 10 230 10 10 10 10 OCT 270 160 150 60 10
NOV 60 60 450 400 400 320 190 180 NOV 830 1,010 810 260 130
DEC 660 620 600 460 420 490 180 80 DEC 790 710 690 450 330
mean 408 396 395 398 312 254 158 110 mean 583 550 496 509 265
std dev 263 278 231 163 184 181 132 104 std dev 361 396 314 456 217
median 440 500 455 440 390 335 185 70 median 495 490 450 440 325
max 840 870 720 590 540 490 320 260 max 1,290 1,430 1,130 1,630 620
min 10 10 10 10 10 10 10 10 min 10 10 60 30 10
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 200 1,140 840 4,320 4,260 830 1,390 610 520 JAN 1,040 40 350 2,160 1,840 1,420 430 980 920
FEB 320 1,040 560 3,580 3,660 380 1,070 580 620 FEB 830 20 280 1,680 1,380 950 380 1,020 720
MAR 440 1,070 880 3,940 3,960 560 990 610 500 MAR 540 10 160 1,300 810 370 130 490 320
APR 160 340 40 2,490 1,950 450 1,000 470 150 APR 540 10 590 1,010 580 310 230 410 680
MAY 50 440 50 730 300 370 3,880 340 430 MAY 400 220 410 600 400 1,700 50 840 120
JUN 10 330 120 2,490 200 370 8,090 230 440 JUN 240 40 290 680 440 300 90 700 130
JUL 10 520 180 340 280 240 80 10 JUL 150 10 430 440 340 1,840 40 80 100
AUG 10 190 10 690 10 30 5,420 10 170 AUG 230 10 280 60 10 220 60 510 40
SEP 10 50 10 130 190 10 290 10 10 SEP 160 10 230 1,220 650 1,200 100 440 80
OCT 10 20 10 190 100 10 1,400 30 30 OCT 10 10 10 20 10 10 10 10 10
NOV 460 10 870 100 110 2,580 140 320 NOV 320 10 150 1,040 490 590 10 600 760
DEC 390 420 10 1,800 2,240 390 1,850 370 390 DEC 290 10 140 1,020 570 430 20 610 600
mean 146 502 231 1,784 1,443 316 2,350 290 299 mean 396 33 277 936 627 778 129 558 373
std dev 168 384 350 1,546 1,689 247 2,352 238 217 std dev 298 60 156 627 525 623 143 311 336
median 50 430 40 1,335 320 370 1,395 285 355 median 305 10 280 1,015 530 510 75 555 225
max 440 1,140 880 4,320 4,260 830 8,090 610 620 max 1,040 220 590 2,160 1,840 1,840 430 1,020 920
min 10 20 10 130 10 10 240 10 10 min 10 10 10 20 10 10 10 10 10
36
0
100
200
300
400
500
600
700
NC11 AC DP IC NAV HB BRR M61 M54 M35 M23 M18 NCF117 NCF6 B210
Ni
t
r
a
t
e
+
N
i
t
r
i
t
e
(
µg/
L
)
Figure 2.4 Nitrate + Nitrite at the Lower Cape Fear River Program mainstem stations, 1995-2018 versus 2019.
1995-2018
2019
37
Table 2.11 Ammonia (µg/l) 2019 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 50 60 40 60 70 80 80 80 JAN 50 50 50 40 40
FEB 80 90 80 110 140 130 110 390 FEB 40 40 40 60 50
MAR 80 100 90 80 100 90 100 50 MAR 50 50 60 60 80
APR 130 80 90 90 90 100 70 50 APR 40 170 50 60 60
MAY 80 70 70 100 100 100 70 170 MAY 100 340 50 120 220
JUN 40 20 10 70 100 110 710 620 JUN 10 10 50 30 60
JUL 80 170 60 60 10 10 10 10 JUL 40 110 90 60 50
AUG 180 130 80 80 10 10 10 10 AUG 130 80 130 140 110
SEP 110 130 140 190 70 50 10 10 SEP 170 240 150 190 80
OCT 10 10 10 10 10 10 10 10 OCT 10 10 30 10 10
NOV 140 120 60 60 10 10 710 10 NOV 170 170 170 270 170
DEC 10 20 40 20 70 90 10 10 DEC 90 200 110 50 10
mean 83 83 64 78 65 66 158 118 mean 75 123 82 91 78
std dev 52 50 37 46 45 45 260 193 std dev 57 103 47 76 62
median 80 85 65 75 70 85 70 30 median 50 95 55 60 60
max 180 170 140 190 140 130 710 620 max 170 340 170 270 220min1010101010101010min1010301010
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 230 40 40 310 60 90 50 50 50 JAN 90 220 110 60 50 30 101 230 170
FEB 210 30 10 250 100 50 110 50 60 FEB 40 310 50 40 30 10 30 110 30
MAR 90 10 10 70 40 60 80 30 30 MAR 70 260 120 110 90 50 50 80 50
APR 230 90 60 170 180 140 120 130 100 APR 80 250 110 90 40 70 90 100 110
MAY 280 100 140 130 80 100 100 90 100 MAY 60 2,390 120 50 40 30 510 40 90
JUN 10 30 40 190 220 20 60 10 100 JUN 100 1,870 30 60 40 50 70 70 80
JUL 70 70 100 60 70 500 10 70 JUL 60 210 60 60 50 70 60 70 100
AUG 140 60 10 120 70 120 360 30 10 AUG 120 160 70 1,690 390 620 450 470 170
SEP 280 140 70 140 100 170 260 100 170 SEP 120 200 110 230 110 120 220 110 80
OCT 40 20 10 20 20 10 90 10 10 OCT 10 10 10 10 10 10 10 10
NOV 110 100 100 90 90 120 160 10 NOV 80 90 90 10 120 10 10 110 80
DEC 10 10 10 20 10 80 70 10 50 DEC 10 10 10 10 10 10 10 10 10
mean 145 59 45 135 86 83 160 57 63 mean 70 543 74 202 82 90 134 118 82
std dev 105 43 44 86 61 46 140 52 48 std dev 37 798 42 473 103 170 172 125 53
median 140 50 40 125 75 85 105 40 55 median 75 220 80 60 45 40 65 90 80
max 280 140 140 310 220 170 500 160 170 max 120 2,390 120 1,690 390 620 510 470 170
min 10 10 10 20 10 10 50 10 10 min 10 10 10 10 10 10 10 10 10
38
Table 2.12 Total Kjeldahl Nitrogen (µg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 50 50 50 50 50 300 700 700 JAN 50 600 50 300 500
FEB 600 500 50 500 600 50 50 50 FEB 400 500 600 500 1,600
MAR 500 600 400 500 600 500 300 300 MAR 700 600 600 600 700
APR 1,000 800 800 700 900 700 300 300 APR 700 400 500 800 500
MAY 800 700 600 900 800 700 600 800 MAY 500 1,000 500 700 700
JUN 700 500 400 1,000 2,000 1,700 900 1,300 JUN 300 600 100 1,000 1,200
JUL 1,000 700 900 700 800 600 50 50 JUL 700 1,000 1,100 1,000 1,100
AUG 200 200 200 200 200 100 50 200 AUG 300 300 200 200 300
SEP 1,300 800 1,000 1,100 800 800 800 600 SEP 1,400 700 800 900 1,000
OCT 700 600 500 600 600 700 600 500 OCT 700 800 1,000 900 1,000
NOV 900 700 700 900 600 400 1,200 600 NOV 900 1,100 1,500 1,400 1,200
DEC 800 3,600 700 700 1,100 700 800 1,300 DEC 900 900 1,400 2,500 700
mean 713 813 525 654 754 604 529 558 mean 629 708 696 900 875
std dev 346 907 316 311 486 425 377 423 std dev 354 254 479 602 372
median 750 650 550 700 700 650 600 550 median 700 650 600 850 850
max 1,300 3,600 1,000 1,100 2,000 1,700 1,200 1,300 max 1,400 1,100 1,500 2,500 1,600
min 50 50 50 50 50 50 50 50 min 50 300 50 200 300
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 700 50 200 50 100 50 50 300 50 JAN 600 1,200 600 600 1,000 700 500 1,100 700
FEB 1,400 800 700 700 600 800 900 800 700 FEB 600 1,600 600 700 700 700 700 600 600
MAR 1,200 600 900 900 900 800 900 700 800 MAR 700 900 600 800 800 600 300 600 500
APR 1,700 900 900 1,100 1,400 1,100 2,700 1,200 1,100 APR 900 1,100 700 900 800 1,000 2,000 800 1,000
MAY 1,600 800 600 800 700 800 1,300 1,000 1,000 MAY 900 4,800 900 1,000 1,000 1,300 1,900 600 400
JUN 2,500 2,100 1,800 2,000 2,100 2,000 1,800 1,200 1,700 JUN 1,400 3,100 1,700 1,600 1,400 1,000 1,200 1,000 800
JUL 1,600 1,000 1,100 1,300 800 2,200 900 800 JUL 200 400 200 200 300 400 400 100 200
AUG 500 300 400 400 300 400 500 200 1,500 AUG 1,300 2,400 1,700 1,900 1,500 2,700 1,700 900 500
SEP 1,800 1,300 1,300 1,000 1,200 1,200 1,800 1,500 1,000 SEP 1,100 1,600 1,700 800 900 1,000 1,300 600 300
OCT 1,600 1,200 1,800 900 1,100 1,700 2,200 1,200 800 OCT 700 1,300 800 900 800 800 900 800 700
NOV 50 50 500 300 200 1,600 500 2,900 NOV 800 3,800 1,100 1,200 1,400 900 800 50 1,600
DEC 1,400 800 600 900 800 800 1,000 1,000 1,100 DEC 200 300 200 500 50 400 100 900 1,100
mean 1,455 825 841 863 900 888 1,413 875 1,121 mean 783 1,875 900 925 888 958 983 671 700
std dev 537 569 585 473 562 563 776 393 695 std dev 374 1,388 544 465 430 608 638 325 388
median 1,600 800 700 900 850 800 1,450 950 1,000 median 750 1,450 750 850 850 850 850 700 650
max 2,500 2,100 1,800 2,000 2,100 2,000 2,700 1,500 2,900 max 1,400 4,800 1,700 1,900 1,500 2,700 2,000 1,100 1,600
min 500 50 50 50 100 50 50 200 50 min 200 300 200 200 50 400 100 50 200
39
Table 2.13 Total Phosphorus (µg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 70 90 80 80 80 110 80 80 JAN 100 90 90 80 120
FEB 100 120 50 90 100 50 30 60 FEB 80 90 100 110 160
MAR 170 150 150 140 140 130 120 120 MAR 100 100 170 100 80
APR 900 160 650 230 340 180 140 700 APR 150 70 80 290 10
MAY 250 290 730 180 220 190 240 180 MAY 680 220 150 120 740
JUN 10 90 10 140 170 200 330 140 JUN 170 70 120 130 760
JUL 230 240 190 140 120 110 100 180 JUL 540 280 500 220 200
AUG 320 220 360 200 260 120 210 160 AUG 460 380 370 430 280
SEP 670 410 280 340 600 940 1,050 1,030 SEP 430 410 350 240 110
OCT 150 120 110 120 100 100 90 90 OCT 280 370 340 290 180
NOV 2,040 690 520 770 960 1,060 420 1,680 NOV 590 480 640 700 950
DEC 210 350 600 2,210 1,180 190 2,060 110 DEC 90 170 110 90 80
mean 427 244 311 387 356 282 406 378 mean 306 228 252 233 233
std dev 545 167 244 578 351 325 564 485 std dev 212 144 177 174 306
median 220 190 235 160 195 155 175 150 median 225 195 160 175 170
max 2,040 690 730 2,210 1,180 1,060 2,060 1,680 max 680 480 640 700 700
min 10 90 10 80 80 50 30 60 min 80 70 80 80 80
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 150 70 60 90 140 90 160 120 70 JAN 60 220 40 70 30 80 40 120 140
FEB 150 100 60 80 200 80 140 90 80 FEB 50 150 10 50 10 80 30 50 100
MAR 360 210 120 130 200 180 150 120 110 MAR 300 310 140 260 120 190 200 130 160
APR 380 160 120 150 270 190 290 190 100 APR 90 230 170 310 220 310 250 120 150
MAY 180 160 80 100 220 110 540 100 110 MAY 240 760 100 280 210 900 190 170 270
JUN 340 510 180 390 390 200 1,690 150 220 JUN 370 710 890 940 920 430 100 100 270
JUL 280 360 240 290 200 1,900 190 260 JUL 200 170 110 180 190 1,060 80 110 270
AUG 210 650 140 460 240 240 3,020 70 220 AUG 260 170 120 170 110 440 180 120 250
SEP 1,010 820 900 780 1,200 1,210 1,090 1,130 930 SEP 280 360 280 370 250 580 240 130 390
OCT 390 390 880 470 710 560 1,590 320 310 OCT 390 260 320 480 360 420 280 520 410
NOV 100 60 130 390 140 660 210 540 NOV 60 10 20 140 120 490 60 10 30
DEC 280 120 80 130 140 80 270 90 130 DEC 110 70 50 120 40 190 70 90 110
mean 339 304 244 263 366 273 958 232 257 mean 201 285 188 281 215 431 143 139 213
std dev 229 235 307 208 292 308 877 279 240 std dev 118 221 231 233 234 291 86 121 112
median 280 185 120 140 255 185 600 135 175 median 220 225 115 220 155 425 140 120 205
max 1,010 820 900 780 1,200 1,210 3,020 1,130 930 max 390 760 890 940 920 1,060 280 520 410
min 150 70 60 80 140 80 140 70 70 min 50 10 10 50 10 80 30 10 30
40
0
50
100
150
200
250
300
350
400
450
NC11 AC DP IC NAV HB BRR M61 M54 M35 M23 M18 NCF117 NCF6 B210
To
t
a
l
P
h
o
s
p
h
o
r
u
s
(
µg/
L
)
Figure 2.5 Total Phosphorus at the Lower Cape Fear River Program mainstem stations, 1995-2018 versus 2019.
1995-2018
2019
41
Table 2.14 Orthophosphate (µg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 20 20 20 20 20 20 20 20 JAN 30 40 40 40 30 20
FEB 10 20 10 20 20 20 10 10 FEB 30 20 30 30 30 20
MAR 30 30 40 30 30 20 20 10 MAR 10 10 20 20 10 20
APR 30 30 30 30 0 40 20 20 APR 10 10 10 20 10 10
MAY 30 30 30 40 40 30 20 20 MAY 30 30 30 30 30 40
JUN 50 60 50 40 30 20 20 10 JUN 50 60 60 60 60 30
JUL 40 30 50 40 20 30 20 40 JUL 60 80 70 50 60 10
AUG 60 60 50 40 30 20 20 10 AUG 80 90 90 50 70 20
SEP 50 60 60 60 50 50 20 20 SEP 90 120 70 50 60 40
OCT 40 40 40 40 40 30 20 20 OCT 90 90 90 50 70 40
NOV 40 60 50 30 40 30 20 20 NOV 120 110 120 50 90 40
DEC 60 60 60 50 50 50 30 20 DEC 40 70 50 30 40 20
mean 38 42 41 37 31 30 20 18 mean 53 61 57 40 47 26
std dev 15 17 16 12 14 11 4 8 std dev 35 38 33 13 25 12
median 40 35 45 40 30 30 20 20 median 45 65 55 45 50 20
max 60 60 60 60 50 50 30 40 max 120 120 120 60 90 40
min 10 20 10 20 0 20 10 10 min 10 10 10 20 10 10
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 100 20 20 40 40 20 70 30 30 JAN 20 60 10 30 10 40 10 10 20
FEB 70 10 10 20 40 10 50 20 30 FEB 30 100 10 20 10 50 10 10 20
MAR 120 10 10 20 30 20 50 20 20 MAR 20 100 10 30 10 80 10 10 20
APR 230 40 40 40 60 20 100 70 30 APR 40 90 20 30 10 110 10 10 30
MAY 80 30 40 20 30 20 290 30 30 MAY 50 360 30 70 40 490 10 10 50
JUN 120 40 30 50 50 30 1150 40 40 JUN 40 210 30 80 40 180 20 30 60
JUL 50 70 40 20 50 1100 40 30 JUL 80 100 20 90 70 570 20 50 100
AUG 30 60 10 130 10 20 1570 10 AUG 70 60 50 90 50 110 20
SEP 160 60 60 60 120 40 240 80 50 SEP 50 30 20 40 30 200 5 20 80
OCT 70 50 30 40 130 30 830 50 40 OCT 50 30 30 110 40 90 20 20 80
NOV 20 10 20 50 20 300 40 30 NOV 30 20 10 60 20 180 5 10 40
DEC 130 10 10 20 30 10 150 20 20 DEC 20 20 10 60 20 120 5 10 30
mean 105 35 25 42 51 24 492 38 32 mean 42 98 21 59 29 185 12 17 48
std dev 56 22 17 31 37 12 527 21 9 std dev 19 98 12 29 19 170 6 13 28
median 100 35 20 40 40 20 265 35 30 median 40 75 20 60 25 115 10 10 40
max 230 70 60 130 130 50 1570 80 50 max 80 360 50 110 70 570 20 50 100
min 30 10 10 20 10 10 50 10 20 min 20 20 10 20 10 40 5 10 20
42
Table 2.15 Chlorophyll a (µg/l) 2019 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 4 3 2 2 2 1 2 1 JAN 1 1 1 0 1 1
FEB 13 7 10 7 5 3 4 7 FEB 8 7 7 3 6 2
MAR 3 5 4 4 4 5 5 6 MAR 10 10 10 4 9 3
APR 3 3 3 4 7 10 13 11 APR 14 16 14 4 9 3
MAY 4 4 4 4 3 8 9 11 MAY 7 6 6 4 5 3
JUN 2 2 5 9 10 12 5 4 JUN 3 3 1 2 2 10
JUL 16 15 17 20 42 20 6 7 JUL 6 4 3 2 3 19
AUG 2 4 12 13 13 16 5 4 AUG 2 2 2 1 2 6
SEP 1 2 1 1 4 4 4 5 SEP 5 2 1 1 1 3
OCT 3 3 4 3 2 5 4 6 OCT 7 5 1 1 1 3
NOV 1 1 3 2 3 2 3 3 NOV 1 1 1 1 1 2
DEC 0 0 1 1 1 2 2 4 DEC 2 2 2 2 2 1
mean 4 4 6 6 8 7 5 6 mean 6 5 4 2 4 5
std dev 5 4 5 6 11 6 3 3 std dev 4 4 4 1 3 5
median 3 3 4 4 4 5 5 6 median 6 4 2 2 2 3
max 16 15 17 20 42 20 13 11 max 14 16 14 4 9 19
min 0 0 1 1 1 1 2 1 min 1 1 1 0 1 1
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 1 1 1 2 2 2 1 1 1 JAN 1 2 1 1 1 1 2 3 4
FEB 2 2 2 4 5 20 4 2 9 FEB 1 3 1 2 1 1 8 2 2
MAR 2 2 2 2 3 3 2 2 2 MAR 1 4 1 1 2 1 8 2 2
APR 9 2 2 3 3 2 2 1 4 APR 2 3 1 2 1 1 9 1 2
MAY 5 2 2 10 2 1 0 1 6 MAY 1 2 0 0 0 1 58 1 1
JUN 3 6 20 7 31 2 2 3 6 JUN 1 8 0 1 0 2 27 1 1
JUL 1 4 14 15 3 1 9 15 JUL 1 5 1 1 0 1 6 3 3
AUG 21 2 24 22 12 3 3 12 23 AUG 2 4 1 2 1 4 13 2 4
SEP 9 1 1 5 52 4 1 1 4 SEP 1 1 0 1 1 1 13 2 0
OCT 18 2 175 12 19 6 4 2 9 OCT 2 2 0 1 1 1 10 3 1
NOV 2 1 2 2 0 3 2 4 NOV 1 1 0 1 1 1 3 3 1
DEC 2 2 1 2 4 2 0 1 2 DEC 1 1 0 1 1 1 4 2 1
mean 7 2 21 7 13 4 2 3 7 mean 1 3 1 1 1 1 13 2 2
std dev 7 1 52 6 15 5 1 4 6 std dev 0 2 1 1 1 1 16 1 1
median 3 2 2 5 5 3 2 2 5 median 1 3 1 1 1 1 9 2 2
max 21 6 175 22 52 20 4 12 23 max 2 8 1 2 2 4 58 3 4
min 1 1 1 2 2 0 0 1 1 min 1 1 0 0 0 1 2 1 0
43
0
1
2
3
4
5
6
7
8
9
NC11 AC DP IC NAV HB BRR M61 M54 M35 M23 M18 NCF117 NCF6 B210 BBT
Ch
l
o
r
o
p
h
y
l
l
a
(µg/
L
)
Figure 2.6 Chlorophyll a at the Lower Cape Fear River Program mainstem stations, 1995-2018
versus 2019.
1995-2018
2019
44
Table 2.16 Fecal Coliform (cfu/100 mL) and Enterococcus (MPN) 2019 at the Lower Cape Fear River Program stations.
ENTEROCOCCUS
NC11 AC DP IC NCF6 NAV HB BRR M61 M54 M35 M23 M18
JAN 50 59 110 86 23 14 23 JAN 20 5 5 63 5 5
FEB 5 10 10 5 19 17 23 FEB 5 5 5 52 10 5
MAR 41 68 37 64 50 55 19 MAR 5 16 22 45 30 85
APR 10 5 10 14 41 5 5 APR 10 5 5 5 10 10
MAY 10 10 5 28 28 5 5 MAY 1 1 1 1 132 19
JUN 240 5 5 23 77 79 68 JUN 31 20 10 5 5 5
JUL 5 5 10 19 23 105 145 JUL 31 20 10 5 5 5
AUG 5 16 5 5 32 19 14 AUG 42 274 313 190 550 550
SEP 32 5 14 14 22 110 135 SEP 630 10 10 10 5 5
OCT 5 5 5 5 23 73 68 OCT 99 69 89 180 85 462
NOV 5 5 14 37 41 5 41 NOV 6 7 5 1 1 1
DEC 10 5 32 5 10 14 23 DEC 11 21 19 15 22 145
mean 35 17 21 25 32 42 47 mean 74 38 41 48 72 108
std dev 64 21 29 25 17 39 46 std dev 170 73 85 65 149 184
max 240 68 110 86 77 110 145 max 630 274 313 190 550 550
min 5 5 5 5 10 5 5 min 1 1 1 1 1 1
Geomean 14 9 13 16 29 24 29 Geomean 18 13 12 15 16 19
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 32 115 10 23 50 10 95 14 5 JAN 28 5 5 50 46 5 37 235 230
FEB 60 19 28 14 10 5 68 77 5 FEB 55 32 165 180 73 64 100 182 170
MAR 135 64 19 23 10 82 200 50 37 MAR 10 5 5 130 23 50 64 14
APR 82 155 55 135 165 130 82 10 14 APR 57 190 41 135 125 120 110 319 228
MAY 1,000 319 105 115 160 295 290 32 5 MAY 55 105 91 95 32 37 240 182 205
JUN 19 125 37 14 150 37 46 10 50 JUN 10 205 23 46 19 86 125 115 100
JUL 5 235 32 160 155 23 5 68 JUL 10 19 10 10 59 23 195 500 82
AUG 1,000 105 64 180 500 591 210 14 64 AUG 37 125 68 228 82 55 410 1,050 220
SEP 180 637 682 10,500 2,800 1,300 100 145 240 SEP 14 23 23 95 68 19 37 160 280
OCT 118 125 273 210 1050 185 140 23 23 OCT 110 245 115 455 364 319 182 364 215
NOV 120 32 55 200 290 140 23 37 NOV 28 100 105 55 46 41 5 255 109
DEC 14 82 41 41 110 140 150 10 22 DEC 37 28 68 68 37 37 19 200 175
mean 240 175 122 945 447 268 129 34 48 mean 38 90 60 129 81 73 126 302 169
std dev 362 158 190 2,882 761 348 73 39 62 std dev 28 82 49 115 90 84 112 252 74
max 60 637 682 10,500 2,800 1,300 290 145 240 max 110 245 165 455 364 319 410 1,050 280
min 5 19 10 14 10 5 23 5 5 min 10 5 5 10 19 5 5 64 14
Geomean 77 126 56 77 147 115 106 21 25 Geomean 28 47 36 89 57 45 75 235 139
45
0
10
20
30
40
50
60
70
NC11 AC DP IC NAV HB NCF117 NCF6 B210 BRR M61 M54 M35 M23 M18
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
C
F
U
/
1
0
0
m
L
)
Figure 2.7 Geometric Mean Fecal Coliform (NC11-B210) and Enterococcus (BRR-M18) at the LCFRP mainstem stations, 1996-2018 (Entero 2012-2014 ) vs. 2019.
1996-2018
2019
46