Lower Cape Fear River Program 2016 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2016
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
August 2017
CMS Report No. 17-02
Center for Marine Science
University of North Carolina Wilmington
Wilmington, N.C. 28409
Executive Summary
Multiparameter water 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. 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 2016. 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) 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 have until recently been rare because light is attenuated by water color or
turbidity, and flushing is usually high (Ensign et al. 2004). During periods of low flow (as
in 2008-2012) algal biomass as chlorophyll a increases in the 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, some of which periodically show elevated
pollutant loads or effects (Mallin et al. 2001). Average annual dissolved oxygen (DO) levels at the river channel stations for 2016
were generally comparable to the average for 1995-2015. Dissolved oxygen levels
were lowest during the summer and early fall, often falling below the state standard of
5.0 mg/L at several river and upper estuary stations. 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 were highest at the upper river stations NC11 and AC and in the middle
to lower estuary at stations M35 to M18. Lowest mainstem average 2016 DO levels
occurred at the lower river and upper estuary stations IC, NAV, HB, BRR and M61 (6.4-6.7 mg/L). As the water reaches the lower estuary higher algal productivity, mixing and ocean dilution help alleviate oxygen problems.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River. These rivers are classified as blackwater systems because of their tea colored water. The Northeast Cape Fear River generally has lower
dissolved oxygen than the Black River; as such, in 2016 Stations NCF117 and B210, representing those rivers, had average DO concentrations of 5.3 and 6.7 mg/L,
respectively. Several stream stations were stressed in terms of low dissolved oxygen
during the year 2016, including NC403, GS, and SR. The Northeast Cape Fear River
station NCF117 had DO below 4.0 mg/L on 5 of 12 occasions in 2016. Considering all sites sampled in 2016, we rated 9% as poor for dissolved oxygen, 34% as fair, and 56% as good.
Annual mean turbidity levels for 2016 were lower than the long-term average in all
estuary stations. Highest mean riverine turbidities were at NC11-DP (18-21 NTU) with turbidities generally low in the middle to lower estuary. The estuarine stations did not exceed the estuarine turbidity standard on our sampling trips except in March 2016.
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, with the exception of one excursion to 83 NTU in September at BRN and 59 NTU at HAM. 97% of the stations were rated as good for turbidity.
Average chlorophyll a concentrations across most sites were low in 2016. The standard
of 40 µg/L was exceeded once at Station PB and once at SR, although those sites
hosted several smaller algal blooms as well. We note the highest levels in the river and estuary typically occur late spring to late-summer. During the growing season May-September river flow as measured by USGS at Lock and Dam #1 was double the
average for the blue-green algal bloom years 2009-2012 (3,427 CFS compared with
1,698 CFS) washing out any significant algal bloom formation. For the 2016 period
UNCW rated all of the stations as good in terms of chlorophyll a. Fecal coliform counts in the river and at many of the stream stations were very high in
2016. Three main river sites, DP, NAV and HB were rated as poor, while the estuarine
stations were mostly rated as good to fair for Enterococcus. All of the stream stations in
the Northeast Cape Fear basin were rated as poor for fecal coliforms, as were most stations in the Black River basin. For bacterial water quality overall, 61% of the sites rated as poor, 23% as fair, and only 16% as good in 2016.
In addition, by our UNCW standards excessive nitrate and phosphorus concentrations
were problematic at a number of stations.
Table of Contents
1.0 Introduction...........................................................................………...............…........1
1.1 Site Description................................................………....................................2 1.2 Report Organization………………………………………………………..……..3
2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River
and Estuary………………………………………………..……………………................7 Physical Parameters..…......................………..........................................……....10
Chemical Parameters…....……..……….........................................................…..14
Biological Parameters.......……….....……......................................................…..17
1.0 Introduction
Michael A. Mallin
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 2016.
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
21-year (1995-2016) data base that is available to the public, and is used as a teaching
tool for programs like UNCW’s River Run. Using this monitoring data as a framework
the program goals also include focused scientific projects and investigation of pollutionepisodes. The scientific aspects of the program are carried out by investigators fromthe 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 Water
Resources, The NC Division of Marine Fisheries, the US Army Corps of Engineers,technical representatives from streamside industries, the Cape Fear Public UtilityAuthority, 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.
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
Benthic Ecology Laboratory under Sea Grant and NSF sponsored projects in the Cape Fear Estuary. These data are collected and analyzed depending upon the availability of
1
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. The
regular sampling that was conducted by UNCW biologists was assumed by the North
Carolina Division of Marine Fisheries.
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 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 Dan #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 river
2
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
This report contains two sections assessing LCFRP data. Section 2 presents an 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. NCDENR. 2005. Cape Fear River Basinwide Water Quality Plan. North Carolina Department of Environment and Resources, Division of Water Quality/Planning, Raleigh, NC, 27699 Natural -1617.
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Table 1.1 Description of sampling locations in Lower Cape Fear River Watershed, 2016
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
LVC2 B8441000 Livingston Creek at Momentive
Walkway nr Acme
DWR ambient station, Downstream
of Momentive Columbus 34.3353-78.2011 C 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
23
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
4
Collected by Land
6RC Six Runs Creek at SR 1003 nr Ingold B8740000 Sampson 34.7933-78.3113 C Sw ORW+03030006
LCO Little Coharie Creek at SR 1207 nr
Ingold B8610001 Sampson 34.8347-78.3709 C Sw 03030006
GCO Great Coharie Creek at SR 1214 nr
Butler Crossroads B8604000 Sampson 34.9186-78.3887 C Sw 03030006
SR South River at US 13 nr Cooper B8470000 Sampson 35.156-78.6401 C Sw 03030006
BRN Browns Creek at NC87 nr
Elizabethtown B8340050 Bladen 34.6136-78.5848 C 03030005
HAM Hammond Creek at SR 1704 nr Mt.
Olive B8340200 Bladen 34.5685-78.5515 C 03030005
COL Colly Creek at NC 53 at Colly B8981000 Bladen 34.4641-78.2569 C Sw 03030006
B210 Black River at NC 210 at Still Bluff B9000000 Pender 34.4312-78.1441 C Sw ORW+03030006
NC403 NE Cape Fear River at NC 403 nr
Williams B9090000 Duplin 35.1784-77.9807 C Sw 0303007
PB Panther Branch (Creek) nr Faison B9130000 Duplin 35.1345-78.1363 C Sw 0303007
GS Goshen Swamp at NC 11 and NC 903
nr Kornegay B9191000 Duplin 35.0281-77.8516 C Sw 0303007
SAR NE Cape Fear River SR 1700 nr
Sarecta B9191500 Duplin 34.9801-77.8622 C Sw 0303007
ROC Rockfish Creek at US 117 nr Wallace B9430000 Duplin 34.7168-77.9795 C Sw 0303007
LRC Little Rockfish Creek at NC 11 nr
Wallace B9460000 Duplin 34.7224-77.9814 C Sw 0303007
ANC Angola Creek at NC 53 nr Maple Hill B9490000 Pender 34.6562-77.7351 C Sw 0303007
SR WC South River at SR 1007
(Wildcat/Ennis Bridge Road)B8920000 Sampson 34.6402-78.3116 C Sw ORW+03030006
NCF117 NE Cape Fear River at US 117 at
Castle Hayne B9580000 New Hanover 34.3637-77.8965 B Sw 0303007
SC-CH Smith Creek at US 117 and NC 133 at
Wilmington B9720000 New Hanover 34.2586-77.9391 C Sw 0303007
5
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 2016 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. Selected biological parameters
including fecal coliform bacteria or enterococcus bacteria and chlorophyll a were
examined. 2.2 - Materials and Methods
All samples and field parameters collected for the estuarine stations of the Cape Fear
River (NAV down through M18) were gathered 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 Water Quality inspect UNCW laboratory procedures and periodically accompany field teams to verify proper procedures are followed. By agreement with N.C. Division of Water Quality, after June
2011 sampling was discontinued at stations M42 and SPD, but full sampling was added at
SC-CH and SR-WC in 2012. We note the Town of Burgaw left the program as of 2013
and Stations BCRR and BC117 are no longer being sampled. 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 6920 (or 6820) multi-parameter water quality sonde displayed on a YSI 650 MDS. Each
parameter is measured with individual probes on the sonde. At stations sampled by boat
(see Table 1.1) physical parameters were measured at 0.1 m and at the bottom (up to 12
m); only surface data are reported within. Occasionally, high flow prohibited the sonde from reaching the actual bottom and measurements were taken as deep as possible. At
7
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 Water 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 six hours
before analysis. After August 2011 the fecal coliform analysis was changed to Enterococcus in the estuarine stations downstream of NAV and HB (Stations BRR, M61,
M35, M23 and M18).
8
Chlorophyll a
The analytical method used to measure chlorophyll a is described in Welschmeyer (1994)
and US EPA (1997) and was performed by CMS 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 Water Quality for the analysis of
chlorophyll a (chlorophyll at four LCFRP stations are required by NCDWR to be analyzed
by state-certified methods). 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 program funding.
Parameter Method NC DWR 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
Parameter Method NC DWR Certified
Total Nitrogen By addition
9
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 P E-1999 Yes
Orthophosphate EPA 365.5 No
Fecal Coliform SM 9222 D-1997 Yes
Enterococcus Enterolert IDEXX Yes
Lower Cape Fear River Program 2015/2016 Metals Sampling
The Lower Cape Fear River Program began voluntary metals sampling at two estuarine
locations at Channel Markers 23 and 35 during 2015/2016. This sampling was suggested
by the NC Division of Water Resources Coalition Monitoring Program Coordinator in order to assess the 303d listing (impaired) at these sites using the newly established protocols
for dissolved metals analysis. The US EPA has determined that dissolved metals, rather
than total metals, is more appropriate to assess toxicity to aquatic life.
In December 2015 the LCFRP began collecting a series of ten samples which was completed in October 2016. The methodology involved filtering ambient water in the field
and preservation with nitric acid following the Standard Operating Procedure from an
addendum to the NC Division of Water Resources –Intensive Survey Branch ‐ Standard
Operating Procedures Manual: Physical and Chemical Monitoring, version 2.1, December
2013; ISB‐SOP.
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 2016. Discussion of the
data focuses both on the river channel stations and stream stations, which sometimes
reflect poorer water quality than mainstem stations. The contributions of the two large
blackwater tributaries, the Northeast Cape Fear River and the Black River, are represented by conditions at NCF117 and B210, respectively. The Cape Fear Region experienced
some impacts from Hurricane Matthew October 8-9, 2016, although not to the extent of the
major hurricanes in 1996, 1998, and 1999. Therefore this report reflects low to medium
growing season (May-September) flow conditions for the Cape Fear River and Estuary.
Physical Parameters
Water temperature
Water temperatures at all stations ranged from 4.1 to 31.4oC, and individual station annual averages ranged from 16.2 to 20.6oC (Table 2.1). Highest temperatures occurred during
10
July and August 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 34.2 practical salinity units (psu) and station annual means
ranged from 0.6 to 26.4 psu (Table 2.2). Lowest salinities occurred in late spring and
early-summer and in October from Hurricane Matthew, and highest salinities occurred in late fall and winter. The annual mean salinity for 2016 was slightly lower than that of the nineteen-year average for 1995-2015 for all of the estuarine stations (Figure 2.1). Two
stream stations, NC403 and PB, had occasional oligohaline conditions due to discharges
from pickle production facilities. SC-CH is a tidal creek that enters the Northeast Cape
Fear River upstream of Wilmington and salinity there ranged from 0.0 to 4.5 psu. Conductivity
Conductivity at the estuarine stations ranged from 0.05 to 52.25 mS/cm and from 0.05 to
3.55 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
pH values ranged from 3.4 to 8.5 and station annual means ranged from 3.9 to 8.0 (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 at this near-pristine stream
station.
Dissolved Oxygen Dissolved oxygen (DO) problems have been a major water quality concern in the lower
Cape Fear River and its estuary, and several of the tributary streams (Mallin et al. 1999;
2000; 2001; 2002; 2004; 2005; 2006; 2015). Surface concentrations for all sites in 2016
ranged from 1.8 to 12.5 mg/L and station annual means ranged from 5.3 to 9.1 mg/L (Table 2.5). Average annual DO levels at the river channel and estuarine stations for 2016 were generally comparable to the average for 1995-2015, although 2016 DO values in the
Northeast Cape Fear River were notably lower (Figure 2.2). Dissolved oxygen levels in
the river and estuary, as well as some stream sites, were unseasonably low due to the
influence of Hurricane Matthew. Otherwise, river dissolved oxygen levels were lowest during the summer and early fall (Table 2.5), often falling below the state standard of 5.0
11
mg/L at several river and upper estuary stations. 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.
There is a 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). Mean oxygen levels were highest at the upper river stations NC11 and AC and in the low-to-
middle estuary at stations M35 to M18. Lowest mainstem mean 2016 DO levels occurred
at the river and upper estuary stations HB, BRR and M61 (6.4-6.6 mg/L). Stations M61
and IC were below 5.0 mg/L on 33% or more of occasions sampled, and NAV was on 25% of occasions sampled. Based on number of occasions the river stations were below 5 mg/L UNCW rated M61 and IC as poor for 2016; the mid to lower estuary stations were
rated as fair to good. Discharge of BOD waste from the paper/pulp mill just above the AC
station (Mallin et al. 2003), as well as inflow of blackwater from the Northeast Cape Fear
and Black Rivers, helps to diminish oxygen in the lower river and upper estuary. Additionally, algal blooms periodically form behind Lock and Dam #1 (including the blue-green algal blooms in recent years), and the chlorophyll a they produce is strongly
correlated with BOD at Station NC11 (Mallin et al. 2006); thus the 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. We note that DO conditions in the lower river and estuary in 2016 were an improvement from 2015.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River (NCF117 2016 mean = 5.3, NCF6 = 5.9, B210 2016 mean =
6.7, all decreased from 2015). These rivers are classified as blackwater systems because of their tea colored water. As the water passes through swamps en route to the river channel, tannins from decaying vegetation leach into the water, resulting in the observed
color. Decaying vegetation on the swamp floor has an elevated biochemical oxygen
demand and usurps oxygen from the water, leading to naturally low dissolved oxygen
levels. Runoff from concentrated animal feeding operations (CAFOs) may also contribute to chronic low dissolved oxygen levels in these blackwater rivers (Mallin et al. 1998; 1999; 2006; Mallin 2000). We note that phosphorus and nitrogen (components of animal
manure) levels have been positively correlated with BOD in the blackwater rivers and their
major tributaries (Mallin et al. 2006).
Several stream stations were stressed in terms of low dissolved oxygen during the year 2016. Station GS, SR and SC-CH were below 4.0 mg/L 25% of the occasions sampled,
while the others were in the fair to good range (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
12
possibly SR, especially via nutrient loading (Mallin et al. 2001; 2002; 2004). Hypoxia is thus a continuing problem, with 43% of the sites impacted in 2016.
Field Turbidity
Field turbidity levels ranged from 1 to 83 Nephelometric turbidity units (NTU) and station annual means ranged from 2 to 21 NTU (Table 2.6). The State standard for estuarine
turbidity is 25 NTU. Highest mean turbidities were at NC11-AC (20-21 NTU), plus DP (18
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 2016 sampling trips except during March. As in the previous year, mean turbidity levels for 2016 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, with the
exception of one excursion to 83 NTU at BRN and 59 NTU at HAM in September. 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 notes that transport of samples and temperature
change alters true turbidity readings. Our analysis of samples using both methods shows
that lab turbidity is nearly always lower than field turbidity; thus we do not discuss lab turbidity in this report.
Total Suspended Solids
A new monitoring plan was developed for the LCFRP in September 2011. These changes were suggested by the NC Division of Water Resources (then DWQ). NCDWR 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 DWQ NPDES Unit to evaluate discharges. No LCFRP subscribers discharge in these areas.
Total suspended solid (TSS) values system wide ranged from 1.3 to 49.5 mg/L with station
annual means from 2.5 to 17.2 mg/L (Table 2.7). The overall highest river values were at NC11, M54 and M18. In the stream stations TSS was generally considerably lower than
the river and estuary, except for a peak incident of 49.5 mg/L at Station PB. 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
13
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 a few occasions in the 2016 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. River and
estuary light attenuation coefficients ranged from 0.73 to 6.25/m and station annual means
ranged from 1.70 at M18 to 3.63 at HB (Table 2.8). Elevated mean and median light
attenuation occurred from DP in the lower 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 did 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
color this attenuation tends to limit light availability to the phytoplankton (Mallin et al. 1997;
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 8,010 µg/L and station annual means
ranged from 443 to 3,157 µg/L (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 M54, then declining into the lower estuary, most likely reflecting uptake of nitrogen into
the food chain through algal productivity and subsequent grazing by planktivores as well
as through dilution and marsh denitrification. The highest median TN value at the stream
stations was at ROC, with 2,290 µg/L; other elevated TN values were seen at PB, NC403, 6RC and ANC.
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 6,810 µg/L and station annual means ranged from 29 to 2,192 µg/L (Table 2.10). The
14
highest average riverine nitrate levels were at NC11, AC and DP (455-491 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 = 292 µg/L) and the Black River (B210 = 318 µg/L). Lowest river nitrate occurred during late spring and early summer. In general, average concentrations in 2016 for the mainstem river were lower than those of the average from
1995-2015, but nitrate in the blackwater rivers was slightly higher than the long-term
average (Fig. 2.4).
Several stream stations showed high levels of nitrate on occasion including ROC, NC403, PB and GCO. ROC and GCO primarily receive non-point agricultural or animal waste
drainage, while point sources contribute to NC403 and PB. Over the past several years 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 nutrients were in the range of 200 to 500 µg/L as N
(Mallin et al. 1998; Mallin et al. 2001; Mallin et al. 2002, Mallin et al. 2004). Thus, we conservatively consider nitrate concentrations exceeding 500 µg/L as N 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 960 µg/L and station annual
means ranged from 22 to 211 µg/L (Table 2.11). River areas with the highest mean
ammonium levels this monitoring period included NC11, which represent what comes into
the system, and AC and DP, which are downstream of a pulp mill discharge, and M61 in the upper estuary. At the stream stations, areas with highest levels of ammonium were COL, NC403, and LRC. COL had two highly unusual peaks of 960 in July and 650 in
August.
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 2,600 µg/L and station annual
means ranged from 425 to 1,267 µg/L (Table 2.12). TKN concentration decreases ocean-ward through the estuary, likely due to ocean dilution and food chain uptake of nitrogen. Several individual peaks at or exceeding 2,000 µg/L occurred in stations SR, NCF6 and
M23. ANC, ROC, COL and SR also had the highest median concentrations.
15
Total Phosphorus
Total phosphorus (TP) concentrations ranged from 10 (detection limit) to 970 µg/L and
station annual means ranged from 43 to 349 µg/L (Table 2.13). For the mainstem and
upper estuary, average TP for 2016 was lower than the 1995-2015 average; however, for
the lower estuary and the Northeast Cape Fear River at Highway 117 TP was higher than
the long-term average (Figure 2.5). In the river TP was highest at the upper riverine channel stations NC11, AC and DP and declined downstream into the estuary. Some of this decline is attributable to the settling of phosphorus-bearing suspended sediments, yet
incorporation of phosphorus into bacteria and algae is also responsible.
The experiments discussed above in the nitrate subsection also involved additions of phosphorus, either as inorganic orthophosphate or a combination of inorganic plus organic P. The experiments showed that additions of P exceeding 500 µg/L led to significant
increases in bacterial counts, as well as significant increases in BOD over control. Thus,
we consider concentrations of phosphorus above 500 µg/L to be potentially problematic to
blackwater streams (Mallin et al. 1998; 2004). Streams periodically exceeding this critical concentration included ROC and GCO; NC403 also yielded some high values. Station
NC403 is downstream of an industrial wastewater discharge, while ROC and GCO are in
non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 870 µg/L and station annual means ranged
from 14 to 204 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).
The Northeast Cape Fear River had higher orthophosphate levels than the Black River.
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. 1997; 1999). In spring, productivity in the
estuary is usually limited by phosphorus (Mallin et al. 1997; 1999).
ROC, ANC and GCO had the highest stream station concentrations. All of those sites are
in non-point source areas.
16
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 collected by the LCFRP. Revised metals sampling was re-initiated in late 2015 and continued through 2016.
Results showed that for both stations sampled (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.
Biological Parameters
Chlorophyll a During this monitoring period in most locations chlorophyll a was low, except for elevated
concentrations in August in the upper and middle estuary (Table 2.15). The state standard
was not exceeded in the river or estuary samples in 2016. 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). System wide, chlorophyll a
ranged from undetectable to 100 µg/L and station annual means ranged from 1-20 µg/L,
higher than in 2014. 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 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
through less suspended material and less blackwater swamp inputs. For the growing
season May-September, long-term (1995-2016) average monthly flow at Lock and Dam #1 was approximately 3,401 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 2016, discharge in May-
September was double the 2009-2012 average at 3,427 CFS. Nuisance cyanobacterial
blooms did not occur in the river and upper estuary that year.
River discharge appears to be a major factor controlling formation and persistence of these
blooms. The blooms in 2009-2012 all occurred when average river discharge for May-
September was below 1,900 CFS. The cyanobacterial blooms were suppressed by
elevated river flow in 2013-2014 and 2016, but flow in 2015 was well within the range when blooms can occur. Clearly other factors are at work in bloom formation.
17
Phytoplankton blooms occasionally occur at the stream stations, with a few occurring at
various months in 2016 (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). Stream station blooms
exceeding the state standard of 40 µg/L occurred on two occasions at Stations PB and SR
and lesser blooms occurred at these and a few other stream sites (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 60,000 CFU/100 mL (60,000 is the
laboratory maximum) and station annual geometric means ranged from 30 to 1,653 CFU/100 mL (Table 2.17). The state human contact standard (200 CFU/100 mL) was exceeded in the mainstem numerous times at the riverine stations from AC through NAV in
2016 (Table 2.17). During 2016 the stream stations showed very high fecal coliform
pollution levels. HAM exceeded 200 CFU/100 mL 92% of the time sampled; BRN 83%,
ANC 75%, ROC, LRC and SC-CH 67%, SAR, GS, NC403, PB, 6RC and SR 50%, GCO and LCO 42%, and NCF117 and COL 33% of the time sampled. Notably excessive counts exceeding 37,000 CFU/100 mL occurred at SAR, NC403, PB, SC-CH, LCO, GCO and
SAR occurred in 2016, mainly in summer and fall. NC403 and PB are located below point
source discharges and the other sites are primarily influenced by non-point source
pollution. Overall, 2016 was a very bad year for fecal coliform counts, with geometric mean counts in the mainstem river and the blackwater tributaries well exceeding the geometric mean for the 1995-2015 period (Fig. 2.6).
Enterococcus counts were initiated in the estuary in mid-2011, as this test is now the
standard used by North Carolina regulators for swimming in salt waters. Sites covered by this test include BRR, M61, M54, M35, M23 and M18. The State has a single-sample level for Tier II swimming areas in which the enterococci level in a Tier II swimming area shall
not exceed a single sample of 276 enterococci per 100 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 2016 stations M35, M23 and M18 all exceeded the standard on two to three occasions, and M54 and BRR exceeded the standard on one occasion. Geometric mean enterococcus counts for 2016 were higher than those of the 2012-2015 period for
the lower Cape Fear Estuary (Fig. 2.6). Overall, elevated fecal coliform and enterococcus
counts are problematic in this system, with 84% of the stations rated as Fair or Poor in
2016.
18
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.
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, M.R. McIver, D.C. Parsons and G.C. Shank. 1997. Nutrient limitation and eutrophication potential in the Cape Fear and New River Estuaries.
Report No. 313. Water Resources Research Institute of the University of North Carolina,
Raleigh, N.C.
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., M.H. Posey, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S. Williams, M.L. Moser and J.F. Merritt. 2000. Environmental Assessment of the Lower Cape Fear River
System, 1999-2000. CMS Report No. 00-01, Center for Marine Science, University of
North Carolina at Wilmington, Wilmington, N.C.
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.
19
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.
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.
20
Table 2.1 Water temperature (oC) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 9.1 9.2 9.0 9.4 9.7 10.6 11.5 12.8 JAN 7.1 7.2 7.2 5.2 7.2 7.3
FEB 7.5 8.0 8.0 8.5 8.6 9.1 9.3 10.0 FEB 6.0 6.4 6.8 6.5 6.6 6.9
MAR 11.0 11.0 11.7 11.7 11.5 11.8 12.1 12.7 MAR 11.5 11.6 11.7 12.6 12.5 13.2
APR 18.1 18.2 18.3 18.3 18.1 17.9 17.7 17.6 APR 20.0 20.0 20.7 20.3 20.2
MAY 21.7 21.9 22.8 22.8 22.4 22.6 22.4 22.1 MAY 22.0 22.1 22.3 21.7 22.4 22.4
JUN 24.4 24.4 25.3 25.2 25.2 25.8 25.6 25.2 JUN 26.4 26.9 26.8 25.8 26.4 26.6
JUL 29.8 29.9 30.0 30.0 29.8 30.0 29.9 29.9 JUL 29.9 29.7 30.2 29.8 30.1 30.5
AUG 30.3 30.9 30.8 30.5 30.5 30.4 29.9 29.7 AUG 31.2 29.0 29.7 29.9 31.1 31.4
SEP 29.6 29.8 29.1 30.1 29.8 29.4 28.9 28.7 SEP 25.7 25.7 26.7 26.2 27.4 25.2
OCT 20.1 20.0 20.8 21.9 21.3 21.0 21.5 23.3 OCT 21.6 21.7 21.7 21.7 21.9 22.8
NOV 15.8 16.0 16.0 16.1 16.1 16.6 17.0 17.6 NOV 18.6 19.0 18.8 18.7 18.9 19.6
DEC 11.4 11.7 11.7 12.1 12.4 13.4 13.4 14.3 DEC 12.6 12.4 12.3 12.0 12.4
mean 19.1 19.3 19.5 19.7 19.6 19.9 19.9 20.3 mean 19.4 19.3 19.6 19.1 19.8 20.6
std dev 8.3 8.3 8.3 8.2 8.1 7.8 7.5 7.1 std dev 8.5 8.2 8.3 8.9 8.5 8.4
median 19.1 19.1 19.6 20.1 19.7 19.5 19.6 19.9 median 20.8 20.9 21.2 21.7 21.1 22.4
max 30.3 30.9 30.8 30.5 30.5 30.4 29.9 29.9 max 31.2 29.7 30.2 29.9 31.1 31.4
min 7.5 8.0 8.0 8.5 8.6 9.1 9.3 10.0 min 6.0 6.4 6.8 5.2 6.6 6.9
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 9.0 5.8 6.3 7.3 5.1 7.6 7.0 8.6 9.3 JAN 9.8 5.4 7.7 6.2 5.2 4.1 4.8 6.2 6.3
FEB 8.0 7.0 7.1 8.0 8.0 8.2 6.5 9.0 8.8 FEB 6.4 7.5 6.5 9.0 8.0 8.1 8.5 8.5 8.8
MAR 11.5 10.2 12.6 11.3 10.7 11.2 10.9 11.3 11.3 MAR 18.3 16.8 17.7 18.0 17.8 17.8 17.2 17.9 17.7
APR 16.3 14.9 17.0 17.5 19.4 16.6 15.9 19.3 18.7 APR 15.4 13.9 14.8 14.4 14.2 14.9 14.8 16.1 15.4
MAY 20.7 20.6 22.0 21.9 22.6 21.3 19.5 21.2 21.6 MAY 19.5 18.2 18.9 18.8 19.1 18.9 18.4 18.8 18.5
JUN 29.8 24.3 24.8 25.2 25.8 22.9 23.4 26.2 26.8 JUN 25.6 23.4 25.2 25.3 24.8 26.3 25.9 24.2 23.8
JUL 25.5 26.3 27.4 27.7 28.1 25.7 26.4 29.5 29.7 JUL 30.0 27.2 28.4 28.0 28.4 29.1 30.0 27.2 27.7
AUG 25.6 26.9 26.6 27.2 27.4 26.7 26.0 29.8 30.1 AUG 28.0 25.3 26.1 25.7 25.7 26.3 26.5 24.9 25.1
SEP 23.4 24.5 25.6 25.5 27.6 24.9 23.6 25.2 25.6 SEP 24.7 22.9 23.0 22.9 22.9 22.5 21.7 21.3 21.3
OCT 20.8 21.4 21.5 21.8 20.8 20.0 20.5 OCT 16.2 14.5 15.3 15.3 14.9 14.4 14.1 15.7 14.3
NOV 18.0 17.1 18.3 18.5 18.0 16.9 18.2 19.2 NOV 10.5 10.9 10.5 10.6 10.8 11.3 11.3 13.7 13.0
DEC 11.7 10.7 12.5 12.1 11.8 11.4 11.0 13.2 13.9 DEC 8.2 7.8 7.7 8.8 8.3 6.5 6.2 7.8 7.7
mean 18.4 17.5 18.5 18.4 18.6 18.0 17.3 19.3 19.6 mean 17.7 16.2 16.8 16.9 16.7 16.7 16.6 16.9 16.6
std dev 7.1 7.6 7.4 8.1 8.5 6.9 7.1 7.5 7.6 std dev 8.0 7.4 7.7 7.4 7.7 8.3 8.2 6.9 7.0
median 19.4 18.9 19.9 19.7 19.4 19.7 18.2 19.7 19.9 median 17.3 15.7 16.5 16.7 16.4 16.4 16.0 17.0 16.6
max 29.8 26.9 27.4 27.7 28.1 26.7 26.4 29.8 30.1 max 30.0 27.2 28.4 28.0 28.4 29.1 30.0 27.2 27.7
min 8.0 5.8 6.3 7.3 5.1 7.6 6.5 8.6 8.8 min 6.4 5.4 6.5 6.2 5.2 4.1 4.8 6.2 6.3
21
Table 2.2 Salinity (psu) during 2016 at the Lower Cape Fear River Program estuarine stations.
NAV HB BRR M61 M54 M35 M23 M18 NCF6 SC-CH
JAN 0.0 0.1 0.1 0.1 0.1 6.6 15.4 27.2 0.1 0.1
FEB 0.1 0.1 0.1 0.5 1.0 4.3 7.8 11.5 0.0 0.0
MAR 0.0 0.0 0.0 0.0 0.1 2.4 7.4 14.4 0.1 1.3
APR 0.1 1.8 3.1 7.9 10.7 17.8 24.9 29.1 1.4 0.9
MAY 0.1 0.9 0.4 1.6 4.8 13.4 26.2 28.4 0.1 3.7
JUN 0.1 0.1 1.2 5.9 6.9 12.5 21.6 24.3 0.1 1.8
JUL 0.1 0.1 0.4 7.1 7.9 11.6 20.2 22.5 0.1 2.2
AUG 3.5 4.1 3.5 6.5 12.6 20.3 27.6 34.2 3.1 4.3
SEP 10.9 10.6 13.1 15.3 18.7 27.0 31.6 33.6 0.0 0.6
OCT 0.0 0.0 0.0 0.0 0.0 0.2 1.9 26.0 0.0 0.0
NOV 4.8 5.0 9.0 10.4 16.2 25.3 30.7 32.8 2.1 0.5
DEC 2.0 3.0 3.0 6.0 9.0 22.0 23.0 33.0 4.5
mean 1.8 2.2 2.8 5.1 7.3 13.6 19.9 26.4 0.6 1.7
std dev 3.3 3.2 4.2 4.8 6.4 9.0 9.7 7.4 1.1 1.7
median 0.1 0.5 0.8 6.0 7.4 13.0 22.3 27.8 0.1 1.1
max 10.9 10.6 13.1 15.3 18.7 27.0 31.6 34.2 3.1 4.5
min 0.0 0.0 0.0 0.0 0.0 0.2 1.9 11.5 0.0 0.0
22
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 stations 1995-2015
versus 2016.
1995-2015
2016
23
Table 2.3 Specific Conductivity (mS/cm) during 2016 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 0.10 0.10 0.12 0.33 11.57 25.35 42.32 JAN 0.09 0.13 0.10 0.09 0.11 0.11
FEB 0.10 0.10 0.10 1.05 1.90 7.69 13.47 19.34 FEB 0.08 0.09 0.09 0.06 0.07 0.06
MAR 0.08 0.08 0.09 0.09 0.15 4.46 12.86 23.63 MAR 0.09 0.11 0.11 0.10 0.09 0.28
APR 0.15 3.43 5.70 13.65 18.01 28.75 38.93 44.98 APR 0.12 0.13 0.15 0.13 2.64
MAY 0.11 1.69 0.89 3.07 8.61 22.30 40.94 44.02 MAY 0.12 0.14 0.13 0.10 0.13 0.11
JUN 0.15 0.27 2.26 10.45 12.06 20.93 34.42 38.28 JUN 0.12 0.27 0.18 0.09 0.12 0.12
JUL 0.14 0.16 0.85 1.24 13.76 19.70 32.51 36.43 JUL 0.13 0.17 0.19 0.14 0.16 0.20
AUG 6.39 7.54 6.39 11.44 21.18 32.64 43.05 52.25 AUG 0.14 0.12 0.18 0.17 0.19 5.71
SEP 18.44 18.17 21.90 25.23 30.25 42.22 48.53 51.28 SEP 0.10 0.09 0.14 0.10 0.12 0.07
OCT 0.05 0.05 0.05 0.06 0.06 0.33 3.62 40.03 OCT 0.05 0.06 0.06 0.06 0.06 0.09
NOV 8.51 9.40 15.35 17.38 26.35 39.65 47.09 49.98 NOV 0.10 0.10 0.11 0.10 0.12 3.92
DEC 4.37 6.25 5.75 10.78 15.70 34.97 36.84 49.92 DEC 0.11 0.12 0.15 0.12 0.14
mean 3.21 3.94 4.95 7.88 12.36 22.10 31.47 41.04 mean 0.10 0.13 0.13 0.10 0.12 1.21
std dev 5.63 5.59 6.97 8.25 10.48 13.96 14.58 10.53 std dev 0.02 0.05 0.04 0.03 0.03 1.98
median 0.14 0.98 1.57 6.76 12.91 21.61 35.63 43.17 median 0.11 0.12 0.14 0.10 0.12 0.12
max 18.44 18.17 21.90 25.23 30.25 42.22 48.53 52.25 max 0.14 0.27 0.19 0.17 0.19 5.71
min 0.05 0.05 0.05 0.06 0.06 0.33 3.62 19.34 min 0.05 0.06 0.06 0.06 0.06 0.06
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 0.09 0.14 0.14 0.38 0.79 0.11 0.11 0.09 0.10 JAN 0.07 0.06 0.06 0.11 0.08 0.10 0.07 0.09 0.11
FEB 0.06 0.09 0.09 0.15 0.26 0.05 0.05 0.05 0.06 FEB 0.07 0.05 0.05 0.09 0.08 0.10 0.07 0.07 0.08
MAR 0.07 0.13 0.12 0.26 0.87 0.10 0.10 0.10 2.51 MAR 0.08 0.05 0.07 0.12 0.09 0.13 0.08 0.11 0.15
APR 0.09 0.14 0.14 0.37 1.40 0.12 0.12 0.13 1.76 APR 0.09 0.05 0.07 0.13 0.10 0.14 0.08 0.12 0.15
MAY 0.11 0.18 0.17 0.61 2.92 0.11 0.16 0.16 6.77 MAY 0.08 0.05 0.06 0.12 0.09 0.14 0.08 0.11 0.11
JUN 0.12 0.17 0.16 0.60 3.55 0.14 0.14 0.12 3.44 JUN 0.07 0.06 0.06 0.14 0.11 0.32 0.11 0.12 0.18
JUL 0.08 0.19 0.18 0.69 1.43 0.13 0.29 0.14 4.16 JUL 0.10 0.06 0.07 0.14 0.10 0.15 0.09 0.14 0.25
AUG 0.10 0.25 0.23 0.76 1.55 0.07 0.24 0.18 7.81 AUG 0.13 0.06 0.08 0.15 0.11 0.13 0.10 0.15 0.24
SEP 0.08 0.18 0.18 0.89 3.27 0.10 0.20 0.10 1.21 SEP 0.10 0.07 0.07 0.12 0.09 0.09 0.06 0.06 0.07
OCT 0.07 0.13 0.12 0.11 0.13 0.07 0.07 OCT 0.07 0.06 0.06 0.13 0.09 0.12 0.08 0.12 0.16
NOV 0.07 0.18 0.18 1.13 0.13 0.17 0.12 0.93 NOV 0.10 0.05 0.07 0.14 0.10 0.16 0.09 0.14 0.20
DEC 0.07 0.17 0.17 0.58 0.67 0.12 0.15 0.19 7.96 DEC 0.10 0.06 0.07 0.14 0.10 0.14 0.08 0.13 0.14
mean 0.08 0.16 0.16 0.53 1.62 0.11 0.15 0.12 3.06 mean 0.09 0.06 0.07 0.13 0.09 0.14 0.08 0.11 0.15
std dev 0.02 0.04 0.03 0.23 1.12 0.02 0.06 0.04 2.99 std dev 0.02 0.00 0.01 0.02 0.01 0.06 0.01 0.03 0.06
median 0.08 0.17 0.16 0.59 1.40 0.11 0.14 0.12 2.13 median 0.09 0.06 0.07 0.13 0.10 0.13 0.08 0.12 0.15
max 0.12 0.25 0.23 0.89 3.55 0.14 0.29 0.19 7.96 max 0.13 0.07 0.08 0.15 0.11 0.32 0.11 0.15 0.25
min 0.06 0.09 0.09 0.15 0.26 0.05 0.05 0.05 0.06 min 0.07 0.05 0.05 0.09 0.08 0.09 0.06 0.06 0.07
24
Table 2.4 pH during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 6.8 6.9 7.6 7.2 8.5 8.1 8.1 8.0 JAN 5.8 6.2 6.4 6.0 6.5 6.3
FEB 6.7 6.9 7.1 7.5 7.8 8.0 7.7 8.1 FEB 6.4 6.5 6.5 5.9 6.2 6.0
MAR 6.7 6.8 6.7 6.7 7.0 7.2 7.6 8.0 MAR 6.7 6.8 6.8 6.7 6.5 6.5
APR 7.0 7.0 7.2 7.3 7.4 7.9 8.1 8.1 APR 6.9 7.0 7.0 6.9 6.8
MAY 6.5 6.7 6.6 6.8 7.1 7.6 7.9 8.0 MAY 6.9 7.0 7.0 6.5 6.9 6.5
JUN 6.8 6.8 6.9 6.9 7.2 7.5 7.9 7.9 JUN 6.9 7.1 7.0 6.4 6.7 6.6
JUL 6.7 6.8 6.9 7.1 7.3 7.5 8.0 8.0 JUL 6.7 6.9 6.8 6.5 6.6 6.5
AUG 6.8 6.9 7.2 7.0 7.4 7.9 7.9 8.0 AUG 6.9 6.7 6.7 6.7 6.7 6.9
SEP 7.0 7.0 7.1 7.2 7.5 7.8 7.9 7.9 SEP 6.1 6.3 6.4 5.7 6.2 5.7
OCT 5.4 5.2 5.3 5.6 5.6 6.4 7.2 7.9 OCT 5.8 5.9 6.0 5.9 5.9 6.0
NOV 7.4 7.4 7.4 7.5 7.7 7.9 8.0 8.0 NOV 6.1 6.4 6.3 6.2 6.3 6.4
DEC 7.5 7.6 7.7 7.6 8.0 8.0 8.0 8.0 DEC 5.5 6.4 6.6 6.3 6.5
mean 6.8 6.8 7.0 7.0 7.4 7.7 7.9 8.0 mean 6.4 6.6 6.6 6.3 6.5 6.4
std dev 0.5 0.6 0.6 0.5 0.7 0.5 0.3 0.1 std dev 0.5 0.4 0.3 0.3 0.3 0.4
median 6.8 6.9 7.1 7.2 7.4 7.9 7.9 8.0 median 6.6 6.6 6.7 6.3 6.5 6.5
max 7.5 7.6 7.7 7.6 8.5 8.1 8.1 8.1 max 6.9 7.1 7.0 6.7 6.9 6.9
min 5.4 5.2 5.3 5.6 5.6 6.4 7.2 7.9 min 5.5 5.9 6.0 5.7 5.9 5.7
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 5.9 7.0 7.1 7.0 6.8 6.8 6.6 6.6 6.8 JAN 4.7 3.4 5.0 5.6 5.6 5.8 5.9 5.9 6.1
FEB 3.9 6.1 6.1 6.4 6.2 6.0 5.5 5.6 5.9 FEB 5.8 4.2 5.5 6.3 6.2 6.6 6.4 6.2 6.4
MAR 5.6 6.8 7.2 6.7 6.9 7.2 6.8 6.5 6.7 MAR 6.0 4.0 6.1 6.7 6.6 6.8 6.3 6.8 7.1
APR 6.2 7.0 7.2 6.8 6.8 7.3 7.0 6.7 6.9 APR 6.1 3.9 6.1 6.9 6.7 6.8 6.3 6.8 7.0
MAY 6.5 7.0 7.0 6.9 6.8 7.3 6.9 6.9 6.9 MAY 5.8 3.9 6.1 6.9 6.8 6.8 6.3 6.9 6.9
JUN 6.7 6.9 6.9 6.9 7.0 7.4 6.9 6.6 6.7 JUN 6.1 4.0 6.1 6.9 7.0 7.1 6.5 7.0 7.2
JUL 5.8 6.6 6.6 6.7 6.9 7.5 7.2 6.5 6.7 JUL 6.5 4.3 6.2 7.1 7.0 6.7 6.2 7.1 7.4
AUG 5.9 7.3 6.9 6.8 6.7 6.7 6.9 6.7 6.9 AUG 6.4 4.4 6.0 6.6 6.9 6.7 6.0 6.9 7.2
SEP 5.2 6.5 6.5 6.8 6.9 6.8 6.6 5.7 6.2 SEP 6.4 3.9 5.6 6.1 6.2 6.0 6.1 6.1 6.1
OCT 5.0 6.4 6.7 6.5 6.2 5.3 5.4 OCT 4.8 3.4 5.4 6.1 6.2 6.3 6.5 6.7 6.8
NOV 5.3 6.4 6.9 6.8 6.6 6.4 5.8 6.0 NOV 5.0 3.4 5.6 6.2 6.4 6.5 6.5 6.9 6.9
DEC 5.4 6.6 6.9 6.8 6.8 6.8 6.5 6.9 6.4 DEC 4.9 3.4 5.2 5.9 6.2 6.2 6.2 6.3 6.4
mean 5.6 6.7 6.8 6.8 6.8 6.9 6.6 6.3 6.5 mean 5.7 3.9 5.7 6.4 6.5 6.5 6.3 6.6 6.8
std dev 0.7 0.3 0.3 0.2 0.2 0.4 0.5 0.6 0.5 std dev 0.7 0.4 0.4 0.5 0.4 0.4 0.2 0.4 0.4
median 5.7 6.7 6.9 6.8 6.8 6.8 6.7 6.6 6.7 median 5.9 3.9 5.8 6.5 6.5 6.7 6.3 6.8 6.9
max 6.7 7.3 7.2 7.0 7.0 7.5 7.2 6.9 6.9 max 6.5 4.4 6.2 7.1 7.0 7.1 6.5 7.1 7.4
min 3.9 6.1 6.1 6.4 6.2 6.0 5.5 5.3 5.4 min 4.7 3.4 5.0 5.6 5.6 5.8 5.9 5.9 6.1
25
Table 2.5 Dissolved Oxygen (mg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 9.0 8.9 8.9 8.7 8.8 8.8 8.7 8.3 JAN 10.9 10.8 10.7 10.3 10.8 9.2
FEB 10.6 10.6 10.6 10.3 10.4 10.2 10.1 9.8 FEB 12.0 11.8 11.3 10.8 11.0 10.2
MAR 9.6 9.6 9.5 9.3 9.5 9.9 9.9 9.8 MAR 10.5 10.3 10.4 9.9 9.4 8.7
APR 7.6 7.6 7.5 7.7 7.9 8.5 8.6 8.5 APR 8.7 8.4 8.2 7.6 7.2
MAY 6.0 5.6 5.9 6.1 6.2 7.0 7.2 7.3 MAY 7.5 7.3 7.0 5.5 6.9 4.7
JUN 5.7 5.6 5.1 5.2 5.4 6.1 6.4 6.4 JUN 6.6 6.4 6.1 4.2 5.1 4.1
JUL 5.1 5.1 5.1 4.6 4.9 5.4 6.3 6.4 JUL 6.0 5.6 5.5 4.0 4.9 4.0
AUG 4.1 4.3 6.1 4.4 5.3 6.5 5.7 5.8 AUG 6.3 5.6 4.5 4.5 4.4 5.0
SEP 3.5 3.9 3.8 4.3 5.1 5.5 5.4 5.6 SEP 6.2 6.0 5.6 3.8 5.1 3.7
OCT 3.1 3.1 3.2 2.7 3.0 3.3 4.0 5.8 OCT 4.7 5.0 4.9 3.7 4.1 4.2
NOV 7.0 7.0 7.0 7.2 7.4 7.6 7.5 7.4 NOV 7.9 7.7 5.7 5.0 4.9 4.1
DEC 8.5 8.4 4.5 8.5 8.5 8.3 8.4 7.9 DEC 9.5 9.1 9.0 7.5 8.4
mean 6.7 6.6 6.4 6.6 6.9 7.3 7.4 7.4 mean 8.1 7.8 7.4 6.3 6.9 5.9
std dev 2.5 2.4 2.3 2.4 2.2 2.0 1.9 1.5 std dev 2.3 2.3 2.4 2.8 2.5 2.4
median 6.5 6.3 6.0 6.7 6.8 7.3 7.4 7.4 median 7.7 7.5 6.6 5.0 6.0 4.7
max 10.6 10.6 10.6 10.3 10.4 10.2 10.1 9.8 max 12.0 11.8 11.3 10.8 11.0 10.2
min 3.1 3.1 3.2 2.7 3.0 3.3 4.0 5.6 min 4.7 5.0 4.5 3.7 4.1 3.7
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 10.3 10.9 11.1 10.3 9.4 11.4 10.7 7.7 8.3 JAN 8.3 9.8 9.3 9.9 10.8 11.4 9.7 11.3 11.4
FEB 7.9 10.9 11.2 10.5 11.0 10.9 10.7 8.5 9.0 FEB 11.3 9.4 10.9 10.2 10.9 11.1 11.1 11.2 11.5
MAR 10.6 10.5 12.5 11.2 11.4 12.0 10.6 8.7 9.4 MAR 6.4 6.1 7.5 7.7 7.8 6.8 4.3 8.8 8.9
APR 7.7 7.9 9.4 7.5 6.2 9.5 8.2 6.1 6.9 APR 7.3 7.5 8.4 8.8 8.8 7.9 5.7 8.7 8.5
MAY 5.8 7.1 6.8 6.8 5.1 9.2 7.5 6.1 6.4 MAY 5.5 6.1 7.4 7.9 7.9 7.1 4.1 8.7 8.0
JUN 6.0 5.7 6.1 5.3 3.9 8.6 6.1 3.9 4.4 JUN 4.6 4.9 5.8 6.5 6.6 6.0 1.0 7.5 6.5
JUL 5.1 5.6 5.4 3.7 4.9 7.0 5.7 3.3 4.1 JUL 4.4 4.0 5.7 5.9 6.1 5.0 1.5 7.0 5.8
AUG 4.9 6.3 2.8 3.6 4.6 7.1 5.5 4.3 4.2 AUG 4.7 4.3 5.9 6.2 6.6 6.0 2.2 7.4 6.1
SEP 3.7 5.1 2.5 4.0 9.9 7.5 5.4 2.9 3.4 SEP 5.0 5.4 6.8 7.1 6.9 5.4 5.5 7.4 7.3
OCT 2.5 3.9 2.5 7.5 4.9 1.8 1.8 OCT 5.3 5.6 6.6 8.1 7.2 6.3 4.8 8.9 8.4
NOV 4.8 6.3 5.5 9.5 8.5 7.1 3.0 3.7 NOV 8.5 7.7 9.3 10.1 9.8 9.3 5.5 9.2 7.9
DEC 6.9 8.9 8.9 8.8 8.7 9.8 8.9 7.0 7.7 DEC 9.2 8.3 10.5 10.3 10.3 10.0 9.4 10.5 10.7
mean 6.4 7.4 7.1 7.2 7.7 9.1 7.6 5.3 5.8 mean 6.7 6.6 7.8 8.2 8.3 7.7 5.4 8.9 8.4
std dev 2.5 2.4 3.5 2.9 2.8 1.7 2.2 2.4 2.5 std dev 2.2 1.9 1.8 1.6 1.8 2.2 3.2 1.5 1.9
median 5.9 6.7 6.5 7.2 8.7 8.9 7.3 5.2 5.4 median 6.0 6.1 7.5 8.0 7.9 7.0 5.2 8.8 8.2
max 10.6 10.9 12.5 11.2 11.4 12.0 10.7 8.7 9.4 max 11.3 9.8 10.9 10.3 10.9 11.4 11.1 11.3 11.5
min 2.5 3.9 2.5 3.6 3.9 7.0 4.9 1.8 1.8 min 4.4 4.0 5.7 5.9 6.1 5.0 1.0 7.0 5.8
26
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
1995-2015 versus 2016.
1995-2015
2016
27
Table 2.6 Field Turbidity (NTU) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 14 13 16 18 29 9 7 16 JAN 20 20 20 7 20 4
FEB 10 10 9 7 8 7 5 3 FEB 41 34 30 11 18 8
MAR 57 53 46 42 56 33 18 13 MAR 40 38 32 26 21 14
APR 14 12 11 6 6 5 7 6 APR 22 19 20 16 17
MAY 17 19 18 19 17 9 10 8 MAY 24 25 25 12 20 7
JUN 14 12 8 9 6 4 4 4 JUN 5 5 10 3 7 3
JUL 8 8 7 8 7 6 4 3 JUL 13 13 15 6 8 1
AUG 9 8 8 6 5 3 2 3 AUG 10 10 10 9 8 6
SEP 11 13 11 5 6 3 2 2 SEP 17 16 13 3 6 4
OCT 10 11 12 12 13 21 13 4 OCT 43 47 27 12 21 5
NOV 5 7 5 4 6 6 4 5 NOV 9 8 7 7 6 6
DEC 11 12 9 7 7 8 7 13 DEC 6 7 8 5 6
mean 15 15 13 12 14 10 7 7 mean 21 20 18 9 13 7
std dev 14 12 11 11 15 9 5 5 std dev 14 13 9 6 7 5
median 11 12 10 8 7 7 6 5 median 19 18 18 7 12 6
max 57 53 46 42 56 33 18 16 max 43 47 32 26 21 17
min 5 7 5 4 5 3 2 2 min 5 5 7 3 6 1
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 7 3 2 2 5 7 6 4 6 JAN 3 2 2 3 1 1 4 10 6
FEB 1 5 4 6 35 8 11 10 9 FEB 0 2 0 23 3 0 4 15 13
MAR 14 7 3 6 22 17 13 9 18 MAR 5 5 3 11 6 4 8 8 5
APR 10 4 2 4 11 5 7 5 6 APR 5 6 3 5 4 3 9 45 7
MAY 23 19 3 6 25 5 14 7 15 MAY 6 5 2 9 8 4 9 6 20
JUN 9 5 1 2 16 2 4 4 7 JUN 4 14 3 3 2 3 11 4 5
JUL 42 3 2 2 19 1 4 4 5 JUL 3 3 2 4 3 5 4 4 5
AUG 17 3 4 2 10 8 7 2 14 AUG 3 2 1 3 5 3 6 3 5
SEP 3 6 2 1 6 3 6 2 5 SEP 2 3 3 11 9 2 18 83 59
OCT 3 2 2 4 3 2 4 OCT 2 2 2 3 2 2 4 7 2
NOV 7 3 2 3 5 4 2 11 NOV 3 2 1 4 2 2 3 5 2
DEC 6 3 2 4 8 25 22 4 12 DEC 2 2 1 5 4 2 2 12 7
mean 12 5 2 3 15 8 8 5 9 mean 3 4 2 7 4 3 7 17 11
std dev 11 5 1 2 10 7 6 3 5 std dev 2 3 1 6 3 1 5 24 16
median 8 4 2 3 11 5 7 4 8 median 3 3 2 5 4 3 5 8 6
max 42 19 4 6 35 25 22 10 18 max 6 14 3 23 9 5 18 83 59
min 1 2 1 1 3 1 3 2 4 min 0 2 0 3 1 0 2 3 2
28
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,
1995-2015 versus 2016.
1995-2015
2016
29
Table 2.7 Total Suspended Solids (mg/L) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 7.7 6.2 8.4 10.6 25.4 10.8 11.2 31.1 JAN 22.0 19.5 18.0 20.4 4.5
FEB 7.3 5.1 4.5 5.4 5.5 7.8 10.2 8.2 FEB 24.0 18.4 15.2 7.9 1.4
MAR 21.5 19.4 17.3 16.5 26.8 16.2 11.3 13.3 MAR 16.7 13.7 12.5 8.2 9.0
APR 16.6 16.3 15.6 12.2 13.9 15.8 20.9 11.9 APR 12.0 8.2 7.8 6.4 12.3
MAY 8.4 12.7 9.0 11.9 13.3 11.5 14.8 18.0 MAY 26.5 31.6 26.4 21.2 9.8
JUN 16.7 7.9 7.7 15.7 8.5 9.6 9.9 14.1 JUN 6.1 5.0 9.0 8.8 5.3
JUL 4.6 5.3 5.9 12.3 11.1 12.3 12.4 10.1 JUL 14.9 12.0 17.8 9.5 3.4
AUG 17.0 15.6 16.5 14.5 15.3 13.0 12.4 18.7 AUG 9.6 10.3 9.9 6.6 10.3
SEP 24.1 21.4 24.3 15.1 19.4 12.6 13.7 14.8 SEP 15.9 17.3 9.7 5.4 3.7
OCT 1.5 9.7 8.6 10.6 11.6 20.9 14.1 15.8 OCT 25.0 24.0 29.2 22.2 7.4
NOV 11.7 10.6 8.6 8.9 13.8 16.9 14.8 18.8 NOV 8.3 8.4 8.3 4.8 10.4
DEC 17.2 16.0 13.9 10.1 15.7 25.8 22.0 32.1 DEC 5.9 7.7 9.4 5.0
mean 12.9 12.2 11.7 12.0 15.0 14.4 14.0 17.2 mean 15.6 14.7 14.4 10.5 10.5
std dev 7.0 5.6 5.8 3.2 6.3 5.1 3.9 7.5 std dev 7.4 7.8 7.2 6.6 6.6
median 14.2 11.7 8.8 12.1 13.9 12.8 13.1 15.3 median 15.4 12.9 11.2 9.6 8.1
max 24.1 21.4 24.3 16.5 26.8 25.8 22.0 32.1 max 26.5 31.6 29.2 5.9 22.2
min 1.5 5.1 4.5 5.4 5.5 7.8 9.9 8.2 min 5.9 5.0 7.8 9.7 4.8
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 1.4 1.4 1.4 2.7 4.3 1.4 7.3 JAN 3.0 1.4
FEB 12.3 2.8 8.0 4.7 4.6 6.3 9.0 FEB 1.5 1.4
MAR 1.4 1.4 3.1 5.7 5.3 3.1 7.0 MAR 5.1 5.3
APR 3.8 3.8 9.2 3.0 7.9 6.0 7.8 APR 3.9 4.9
MAY 9.9 3.3 8.5 1.4 5.8 3.3 14.9 MAY 5.8 4.6
JUN 6.2 3.8 10.6 1.5 4.4 3.1 11.8 JUN 2.7 1.4
JUL 4.3 3.3 7.2 2.8 3.6 4.6 10.4 JUL 1.5 4.2
AUG 1.4 5.2 49.5 9.4 5.5 1.4 23.6 AUG 1.4 4.4
SEP 10.8 3.9 9.7 3.3 4.4 1.4 10.0 SEP 1.3 1.3
OCT 4.4 6.7 6.2 2.9 5.7 OCT 1.4 4.3
NOV 2.9 9.6 2.8 1.3 1.3 17.8 NOV 1.3 1.4
DEC 3.1 4.8 6.4 22.3 18.8 4.5 19.1 DEC 1.4 1.3
mean 5.2 3.4 11.2 5.5 6.0 3.3 12.0 mean 2.5 3.0
std dev 3.8 1.3 13.0 5.8 4.3 1.8 5.6 std dev 1.6 1.7
median 4.1 3.6 8.5 3.2 5.0 3.1 10.2 median 1.5 2.8
max 12.3 5.2 49.5 22.3 18.8 6.3 23.6 max 5.8 5.3
min 1.4 1.4 1.4 1.4 1.3 1.3 5.7 min 1.3 1.3
30
Table 2.8 Light Attenuation (k) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 3.45 3.93 3.77 4.48 5.44 3.54 2.58 2.84 JAN 3.12 3.22 3.17 3.60 3.21 4.29
FEB 2.93 2.84 2.71 3.30 3.31 2.86 2.50 2.16 FEB 3.60 3.41 3.40 3.34 3.50 3.82
MAR 4.54 4.27 4.10 4.49 4.73 3.51 2.63 2.34 MAR 3.39 3.48 3.14 3.15 3.42 4.08
APR 3.21 3.25 3.50 2.74 2.18 2.06 1.34 1.33 APR 2.53 2.35 2.59 2.68 4.66
MAY 4.14 4.28 3.86 3.64 3.04 2.06 1.35 1.04 MAY 3.61 3.59 4.05 4.05 3.36 3.95
JUN 3.29 3.58 2.92 2.63 2.27 1.83 1.41 1.59 JUN 2.12 2.74 2.58 3.57 2.57 3.94
JUL 2.35 2.56 2.73 2.87 2.08 1.57 1.66 JUL 2.30 2.58 3.04 2.76 3.00 4.40
AUG 2.80 2.99 4.07 2.67 1.96 1.79 0.74 0.80 AUG 2.30 2.84 3.65 3.26 2.98 3.36
SEP 2.69 2.83 2.52 2.18 1.90 1.44 0.79 0.73 SEP 3.28 3.17 2.74 3.47 2.73 3.66
OCT 4.80 4.64 4.71 5.96 5.83 6.25 4.46 2.59 OCT 3.97 4.72 4.61 4.86 4.65 6.12
NOV 3.39 4.01 2.99 2.67 2.49 1.88 1.29 1.23 NOV
DEC 3.97 4.32 3.50 3.56 2.69 2.46 2.04 2.03 DEC 2.41 2.43 2.89 3.39 2.77
mean 3.46 3.63 3.45 3.43 3.26 2.65 1.89 1.70 mean 2.97 3.14 3.26 3.55 3.17 4.23
std dev 0.76 0.71 0.68 1.08 1.42 1.32 1.04 0.70 std dev 0.65 0.68 0.63 0.57 0.58 0.76
max 4.80 4.64 4.71 5.96 5.83 6.25 4.46 2.84 max 3.97 4.72 4.61 4.86 4.65 6.12
min 2.35 2.56 2.52 2.18 1.90 1.44 0.74 0.73 min 2.12 2.35 2.58 2.76 2.57 3.36
31
Table 2.9 Total Nitrogen (µg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 1,380 1,850 1,540 1,540 1,520 1,190 1,000 1,010 JAN 960 1,180 1,480 1,540 1,610
FEB 1,830 1,780 1,890 2,770 1,720 1,500 2,760 860 FEB 1,560 1,690 1,070 1,700 2,070
MAR 600 530 600 600 740 630 400 300 MAR 440 470 480 580 560
APR 1,000 800 800 800 700 500 400 400 APR 500 1,540 600 700 800
MAY 1,280 1,190 1,290 1,290 1,270 870 350 350 MAY 1,290 1,320 1,400 1,280 2,630
JUN 1,460 1,780 1,470 1,210 1,200 900 330 400 JUN 840 1,320 820 1,090 850
JUL 1,390 1,610 1,470 1,260 1,450 1,030 270 200 JUL 2,000 1,840 1,780 1,510 1,110
AUG 770 760 960 850 650 100 200 200 AUG 550 340 1,120 880 1,160
SEP 1,240 1,110 580 680 680 220 500 300 SEP 1,150 1,170 1,240 1,280 910
OCT 830 1,130 1,110 880 900 1,040 840 300 OCT 1,110 1,590 940 1,120 1,560
NOV 690 720 720 720 630 500 450 500 NOV 750 540 920 720 840
DEC 960 810 1,140 780 860 570 470 500 DEC 1,000 990 990 1,030
mean 1,119 1,173 1,131 1,115 1,027 754 664 443 mean 1,013 1,166 1,070 1,119 1,282
std dev 370 472 415 598 387 408 699 251 std dev 456 494 368 358 628
median 1,120 1,120 1,125 865 880 750 425 375 median 980 1,250 1,030 1,105 1,110
max 1,830 1,850 1,890 2,770 1,720 1,500 2,760 1,010 max 2,000 1,840 1,780 1,700 2,630
min 600 530 580 600 630 100 200 200 min 440 340 480 580 560
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 1,750 2,400 1,970 3,040 2,280 2,070 2,240 1,750 1,440 JAN 1,510 1,240 1,200 2,850 2,060 1,990 1,920 1,490 1,780
FEB 2,550 2,890 3,330 4,470 4,520 1,650 1,610 1,170 1,080 FEB 1,670 850 1,010 2,530 2,430 2,430 1,190 1,270 1,400
MAR 1,200 750 600 740 750 900 900 900 50 MAR 1,000 1,500 1,000 1,100 1,000 1,000 1,300 800 800
APR 800 800 900 1,100 1,000 1,000 1,100 1,000 1,000 APR 1,000 1,500 900 750 1,030 920 1,300 870 600
MAY 1,620 1,310 780 1,950 970 810 2,820 1,320 930 MAY 1,040 1,320 1,020 1,510 1,330 900 1,430 900 720
JUN 1,530 470 530 2,100 1,300 840 2,340 1,500 1,140 JUN 990 1,760 1,170 1,350 1,060 3,820 2,060 1,100 650
JUL 2,280 720 700 780 640 550 7,640 930 950 JUL 630 1,050 610 1,040 780 1,040 1,020 1,220 230
AUG 1,630 1,220 1,100 1,000 1,300 970 8,010 1,130 1,090 AUG 1,550 1,860 540 1,670 1,240 880 1,300 1,490 870
SEP 1,650 1,150 2,600 1,180 2,000 740 3,980 1,010 1,020 SEP 930 1,520 1,050 1,590 1,260 900 1,330 1,030 1,530
OCT 420 640 720 960 1,900 1,060 860 OCT 860 1,000 800 1,490 920 1,020 700 1,040 270
NOV 1,130 720 500 600 980 1,860 840 950 NOV 930 700 790 1,380 1,390 980 460 1,020 200DEC1,130 1,030 400 1,140 650 1,320 3,480 770 700 DEC 880 900 510 1,650 1,380 930 520 870 710
mean 1,474 1,175 1,178 1,750 1,455 1,066 3,157 1,115 934 mean 1,083 1,267 883 1,576 1,323 1,401 1,211 1,092 813
std dev 591 739 943 1,196 1,158 422 2,356 286 330 std dev 318 372 235 591 477 909 491 233 513
median 1,575 915 750 1,160 1,000 965 2,290 1,035 975 median 995 1,280 950 1,500 1,250 990 1,300 1,035 715
max 2,550 2,890 3,330 4,470 4,520 2,070 8,010 1,750 1,440 max 1,670 1,860 1,200 2,850 2,430 3,820 2,060 1,490 1,780
min 420 470 400 740 600 550 900 770 50 min 630 700 510 750 780 880 460 800 200
32
Table 2.10 Nitrate/Nitrite (µg/l) during 2016 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 580 550 540 540 520 390 300 110 JAN 160 280 580 640 610
FEB 930 880 890 870 820 600 560 460 FEB 760 690 670 800 670
MAR 10 30 10 10 40 30 10 10 MAR 40 170 80 80 60
APR 10 10 10 10 10 10 10 10 APR 10 740 10 10 10
MAY 580 490 490 490 470 370 150 50 MAY 790 820 800 780 430
JUN 460 580 470 410 400 200 30 10 JUN 540 520 520 390 350
JUL 690 710 670 460 450 330 70 10 JUL 900 840 780 610 310
AUG 270 260 260 250 150 10 10 10 AUG 450 340 320 380 360
SEP 340 310 280 280 280 20 10 10 SEP 650 570 640 580 310
OCT 130 130 110 80 100 140 140 10 OCT 310 290 240 220 60
NOV 390 420 420 320 230 100 50 10 NOV 250 40 320 120 40
DEC 360 310 440 280 260 170 170 10 DEC 600 590 590 530
mean 396 390 383 333 311 198 126 59 mean 455 491 463 428 292
std dev 275 267 264 246 234 188 163 130 std dev 300 263 264 272 229
median 375 365 430 300 270 155 60 10 median 495 545 550 460 310
max 930 880 890 870 820 600 560 460 max 900 840 800 800 670
min 10 10 10 10 10 10 10 10 min 10 40 10 10 10
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 150 1,500 1,270 2,140 1,580 1,170 1,240 650 440 JAN 410 40 300 1,850 1,260 1,090 220 590 980
FEB 750 2,190 2,530 3,570 3,420 850 910 470 380 FEB 1,170 50 610 1,830 1,930 2,030 690 670 700
MAR 10 50 10 140 50 10 10 10 10 MAR 10 10 10 10 10 10 10 10 10
APR 10 10 10 10 10 10 10 10 10 APR 10 10 10 50 30 20 10 70 10
MAY 120 410 80 1,150 70 110 1,820 420 330 MAY 240 20 220 910 630 300 330 400 220
JUN 130 270 30 1,500 10 240 1,640 700 340 JUN 190 60 270 750 460 2,520 60 500 250
JUL 680 120 10 380 40 250 6,740 430 350 JUL 230 50 210 640 380 440 120 1,020 130
AUG 430 320 10 300 10 270 6,810 330 290 AUG 350 60 340 570 440 180 100 690 70
SEP 50 150 10 580 900 140 2,680 110 220 SEP 230 20 150 590 260 100 330 330 530
OCT 20 40 20 160 700 60 60 OCT 60 10 10 890 420 120 10 640 70
NOV 30 120 10 10 80 860 40 50 NOV 530 10 390 1,080 990 680 60 720 10
DEC 130 430 10 640 250 220 2,880 270 200 DEC 380 10 210 1,050 680 430 20 170 110
mean 209 468 333 1,041 577 293 2,192 292 223 mean 318 29 228 852 624 660 163 484 258
std dev 263 675 780 1,109 1,068 353 2,321 247 155 std dev 313 21 176 572 545 821 203 299 314
median 125 210 10 610 50 190 1,440 300 255 median 235 20 215 820 450 365 80 545 120
max 750 2,190 2,530 3,570 3,420 1,170 6,810 700 440 max 1,170 60 610 1,850 1,930 2,520 690 1,020 980
min 10 10 10 10 10 10 10 10 10 min 10 10 10 10 10 10 10 10 10
33
0
100
200
300
400
500
600
700
800
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,
1995-2015 versus 2016.
1995-2015
2016
34
Table 2.11 Ammonia (µg/l) during 2016 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 20 50 40 60 40 10 60 20 JAN 80 50 40 40 50
FEB 50 50 70 90 100 60 10 40 FEB 30 50 40 30 160
MAR 20 30 30 40 60 40 30 10 MAR 10 50 30 20 60
APR 60 30 40 50 50 10 10 10 APR 120 10 70 60 40
MAY 130 110 80 90 90 10 10 10 MAY 100 110 100 100 90
JUN 60 60 60 80 80 60 30 10 JUN 20 240 90 60 40
JUL 110 70 60 90 80 40 10 10 JUL 400 50 40 30 10
AUG 120 180 50 120 50 20 20 10 AUG 100 70 110 70 60
SEP 10 10 10 10 20 10 10 10 SEP 70 70 100 90 60
OCT 10 10 10 10 10 10 40 40 OCT 10 50 40 30 10
NOV 30 60 80 120 20 10 10 80 NOV 40 170 70 50 60
DEC 50 80 80 110 170 70 50 10 DEC 50 70 70 70
mean 56 62 51 73 64 29 24 22 mean 86 83 67 54 58
std dev 43 47 25 39 44 24 18 22 std dev 106 63 28 25 41
median 50 55 55 85 55 15 15 10 median 60 60 70 55 60
max 130 180 80 120 170 70 60 80 max 400 240 110 100 160
min 10 10 10 10 10 10 10 10 min 10 10 30 20 10
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 190 30 60 40 90 130 70 50 10 JAN 10 80 10 90 30 10 40 90 60
FEB 90 70 50 90 80 60 90 40 140 FEB 20 10 10 60 10 10 10 50 70
MAR 10 10 10 10 10 10 20 60 50 MAR 60 170 50 80 50 560 200 40 40
APR 90 30 480 860 270 70 60 80 70 APR 40 190 40 50 50 40 160 60 30
MAY 260 70 50 120 390 90 100 80 80 MAY 20 120 20 40 20 20 140 20 40
JUN 10 30 10 70 10 90 80 70 40 JUN 60 180 10 10 10 10 600 20 20
JUL 90 30 10 60 100 10 10 20 60 JUL 90 960 60 70 80 130 390 80 80
AUG 110 90 60 230 130 240 140 50 70 AUG 40 650 10 30 10 10 160 10 10
SEP 90 80 40 100 50 130 130 60 60 SEP 30 50 30 70 50 40 50 40 90
OCT 50 10 60 220 110 90 50 OCT 10 40 10 10 50 10 10 40 10
NOV 170 20 10 10 220 50 50 50 NOV 20 50 30 20 20 30 40 30 10
DEC 190 30 30 130 110 770 70 80 90 DEC 10 30 10 40 20 20 10 10 140
mean 113 42 73 171 114 170 78 61 64 mean 34 211 24 48 33 74 151 41 50
std dev 76 28 130 249 118 204 40 20 31 std dev 25 292 18 27 22 157 180 26 40
median 90 30 45 95 90 110 75 60 60 median 25 100 15 45 25 20 95 40 40
max 260 90 480 860 390 770 140 90 140 max 90 960 60 90 80 560 600 90 140
min 10 10 10 10 10 10 10 20 10 min 10 10 10 10 10 10 10 10 10
35
Table 2.12 Total Kjeldahl Nitrogen (µg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 800 1,300 1,000 1,000 1,000 800 700 900 JAN 800 900 900 900 1,000
FEB 900 900 1,000 1,900 900 900 2,200 400 FEB 800 1,000 400 900 1,400
MAR 600 500 600 600 700 600 400 300 MAR 400 300 400 500 500
APR 1,000 800 800 800 700 500 400 400 APR 500 800 600 700 800
MAY 700 700 800 800 800 500 200 300 MAY 500 500 600 500 2,200
JUN 1,000 1,200 1,000 800 800 700 300 400 JUN 300 800 300 700 500
JUL 700 900 800 800 1,000 700 200 200 JUL 1,100 1,000 1,000 900 800
AUG 500 500 700 600 500 100 200 200 AUG 100 50 800 500 800
SEP 900 800 300 400 400 200 500 300 SEP 500 600 600 700 600
OCT 700 1,000 1,000 800 800 900 700 300 OCT 800 1,300 700 900 1,500
NOV 300 300 300 400 400 400 400 500 NOV 500 500 600 600 800DEC600500700500600400300500DEC400400400500
mean 725 783 750 783 717 558 542 392 mean 558 679 608 692 991
std dev 209 301 250 397 208 257 550 188 std dev 271 351 215 173 517
median 700 800 800 800 750 550 400 350 median 500 700 600 700 800
max 1,000 1,300 1,000 1,900 1,000 900 2,200 900 max 1,100 1,300 1,000 900 2,200
min 300 300 300 400 400 100 200 200 min 100 50 300 500 500
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 1,600 900 700 900 700 900 1,000 1,100 1,000 JAN 1,100 1,200 900 1,000 800 900 1,700 900 800
FEB 1,800 700 800 900 1,100 800 700 700 700 FEB 500 800 400 700 500 400 500 600 700
MAR 1,200 700 600 600 700 900 900 900 50 MAR 1,000 1,500 1,000 1,100 1,000 1,000 1,300 800 800
APR 800 800 900 1,100 1,000 1,000 1,100 1,000 1,000 APR 1,000 1,500 900 700 1,000 900 1,300 800 600
MAY 1,500 900 700 800 900 700 1,000 900 600 MAY 800 1,300 800 600 700 600 1,100 500 500
JUN 1,400 200 500 600 1,300 600 700 800 800 JUN 800 1,700 900 600 600 1,300 2,000 600 400
JUL 1,600 600 700 400 600 300 900 500 600 JUL 400 1,000 400 400 400 600 900 200 100
AUG 1,200 900 1,100 700 1,300 700 1,200 800 800 AUG 1,200 1,800 200 1,100 800 700 1,200 800 800
SEP 1,600 1,000 2,600 600 1,100 600 1,300 900 800 SEP 700 1,500 900 1,000 1,000 800 1,000 700 1,000
OCT 400 600 700 800 1,200 1,000 800 OCT 800 1,000 800 600 500 900 700 400 200
NOV 1,100 600 500 600 900 1,000 800 900 NOV 400 700 400 300 400 300 400 300 200
DEC 1,000 600 400 500 400 1,100 600 500 500 DEC 500 900 300 600 700 500 500 700 600
mean 1,267 708 850 710 882 775 967 825 713 mean 767 1,242 658 725 700 742 1,050 608 558
std dev 401 215 582 213 303 214 219 186 259 std dev 274 363 291 267 226 281 491 219 284
median 1,300 700 700 650 900 800 1,000 850 800 median 800 1,250 800 650 700 750 1,050 650 600
max 1,800 1,000 2,600 1,100 1,300 1,100 1,300 1,100 1,000 max 1,200 1,800 1,000 1,100 1,000 1,300 2,000 900 1,000
min 400 200 400 400 400 300 600 500 50 min 400 700 200 300 400 300 400 200 100
36
Table 2.13 Total Phosphorus (µg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 70 50 80 70 100 80 70 70 JAN 70 80 130 80 80
FEB 60 60 60 70 70 70 60 50 FEB 100 80 90 60 70
MAR 30 80 40 90 100 70 60 40 MAR 90 80 80 60 70
APR 120 120 110 90 80 60 40 30 APR 110 100 110 100 100
MAY 130 110 110 110 100 70 50 30 MAY 100 70 100 90 60
JUN 130 110 100 90 80 60 40 40 JUN 80 130 110 100 130
JUL 130 130 140 110 90 110 120 120 JUL 90 80 60 30 10
AUG 110 100 100 90 60 40 30 20 AUG 90 70 100 110 90
SEP 100 170 90 80 100 40 30 30 SEP 130 100 120 100 140
OCT 70 80 80 120 100 110 90 40 OCT 80 90 90 100 90
NOV 80 70 60 60 40 30 10 10 NOV 70 80 80 80 100DEC1301001009080605040DEC190130140120
mean 97 98 89 89 83 67 54 43 mean 100 91 101 86 86
std dev 32 32 26 17 18 24 28 27 std dev 32 20 22 24 33
median 105 100 95 90 85 65 50 40 median 90 80 100 95 90
max 130 170 140 120 100 110 120 120 max 190 130 140 120 120
min 30 50 40 60 40 30 10 10 min 70 70 60 30 30
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 170 80 70 60 190 80 160 80 110 JAN 70 60 10 80 50 90 50 70 70
FEB 210 120 120 110 120 100 150 120 110 FEB 40 60 20 90 40 60 30 70 60
MAR 130 60 40 90 130 60 110 60 150 MAR 80 190 50 120 60 240 70 90 130
APR 210 120 90 140 270 100 260 130 100 APR 90 150 50 90 60 420 50 100 130
MAY 230 140 90 100 260 70 360 100 100 MAY 110 150 40 100 60 360 70 80 110
JUN 200 160 110 130 290 80 350 210 110 JUN 110 200 50 130 90 970 120 80 160
JUL 760 140 110 200 290 50 720 170 90 JUL 140 170 50 160 90 450 90 100 230
AUG 530 160 180 210 400 90 820 130 110 AUG 170 210 60 170 80 400 80 90 230
SEP 370 180 220 150 350 90 520 150 140 SEP 90 30 30 140 100 190 70 160 240
OCT 320 170 220 70 280 150 140 OCT 90 60 50 130 50 220 70 80 110
NOV 170 160 160 310 110 380 140 130 NOV 60 30 10 50 50 400 40 90 90DEC19080901502001108031090DEC7050107030160308080
mean 291 131 125 134 255 84 349 146 115 mean 93 113 36 111 63 330 64 91 137
std dev 177 38 55 45 84 18 225 62 19 std dev 34 68 18 35 21 231 25 23 62
median 210 140 110 135 270 85 315 135 110 median 90 105 45 110 60 300 70 85 120
max 760 180 220 210 400 110 820 310 150 max 170 210 60 170 100 970 120 160 240
min 130 60 40 60 120 50 80 60 90 min 40 30 10 50 30 60 30 70 60
37
0
20
40
60
80
100
120
140
160
180
200
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,
1995-2015 versus 2016.
1995-2015
2016
38
Table 2.14 Orthophosphate (µg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 20 30 30 30 30 30 20 20 JAN 20 20 23 20 20 30
FEB 20 20 20 20 20 20 10 10 FEB 30 30 20 20 20 30
MAR 30 30 30 30 30 20 20 10 MAR 20 20 30 20 20 30
APR 40 40 40 30 30 20 10 0 APR 50 50 50 40 40
MAY 40 40 40 30 30 10 MAY 20 50 60 50 60 60
JUN 50 60 50 40 40 40 20 20 JUN 30 60 50 50 40 60
JUL 60 70 70 40 40 30 10 20 JUL 60 70 60 60 60 50
AUG 40 40 40 40 20 20 20 10 AUG 30 30 40 50 50 40
SEP 40 40 40 40 50 20 20 10 SEP 50 40 50 40 50 80
OCT 30 30 30 60 50 40 40 30 OCT 30 30 30 20 30 40
NOV 30 30 30 30 30 20 10 10 NOV 20 20 20 30 30 50
DEC 40 40 30 40 40 30 20 10 DEC 70 60 60 30 50
mean 37 39 38 36 34 25 18 14 mean 36 40 41 35 39 46
std dev 12 14 13 10 10 9 9 8 std dev 17 18 16 15 15 16
median 40 40 35 35 30 20 20 10 median 30 35 45 30 40 40
max 60 70 70 60 50 40 40 30 max 70 70 60 60 60 80
min 20 20 20 20 20 10 10 0 min 20 20 20 20 20 30
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 100 20 10 30 50 20 50 30 40 JAN 30 30 10 30 10 30 10 20 20
FEB 120 30 40 30 20 30 60 40 40 FEB 10 30 10 30 10 20 0 10 10
MAR 80 20 10 20 30 10 40 20 30 MAR 20 100 10 30 10 110 10 10 20
APR 100 40 30 40 60 20 110 50 40 APR 30 80 10 20 10 230 10 10 30
MAY 130 40 30 50 40 30 180 40 40 MAY 40 90 20 40 20 220 10 20 40
JUN 110 50 40 60 20 20 160 100 60 JUN 40 140 20 50 30 870 10 20 60
JUL 590 60 50 100 80 20 510 90 60 JUL 60 120 20 60 40 220 20 30 90
AUG 350 60 50 120 80 30 560 70 50 AUG 70 120 20 70 30 220 50 30 10
SEP 260 60 60 60 60 30 240 80 70 SEP 50 20 20 60 20 110 20 30 10
OCT 30 70 90 40 20 50 30 90 OCT 30 90 90 50 20 60 30 100 40
NOV 110 50 40 80 20 160 60 60 NOV 30 30 10 20 30 270 0 10 40
DEC 140 20 20 40 20 20 160 30 30 DEC 20 30 10 30 10 90 0 10 20
mean 177 43 39 55 48 23 190 53 51 mean 36 73 21 41 20 204 14 25 33
std dev 156 18 22 32 24 6 173 26 18 std dev 17 43 22 17 10 227 14 25 24
median 115 45 40 45 45 20 160 45 45 median 30 85 15 35 20 165 10 20 25
max 590 70 90 120 80 30 560 100 90 max 70 140 90 70 40 870 50 100 90
min 30 20 10 20 20 10 40 20 30 min 10 20 10 20 10 20 0 10 10
39
Table 2.15 Chlorophyll a (µg/l) during 2016 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 1 1 1 1 2 1 1 5 JAN 2 2 2 1 2 0
FEB 2 2 2 2 2 2 2 3 FEB 2 1 1 1 1 1
MAR 3 3 3 3 3 2 3 6 MAR 8 7 7 5 5 1
APR 2 2 3 4 6 10 8 7 APR 6 4 3 2 3
MAY 1 2 2 4 5 17 6 5 MAY 3 2 2 1 2 1
JUN 2 2 3 2 3 2 3 5 JUN 2 3 4 1 2 1
JUL 4 6 9 11 14 11 12 8 JUL 3 4 5 2 4 2
AUG 13 9 34 23 19 8 3 4 AUG 10 9 7 5 5 21
SEP 7 9 9 7 10 5 3 3 SEP 2 2 4 1 3 1
OCT 0 0 1 1 1 1 1 2 OCT 1 1 1 1 1 0
NOV 1 1 1 12 3 4 3 5 NOV 2 2 1 1 1 1DEC00111121DEC00000
mean 3 3 6 6 6 5 4 5 mean 3 3 3 2 2 3
std dev 4 3 9 7 6 5 3 2 std dev 3 3 2 2 2 6
median 2 2 3 4 3 3 3 5 median 2 2 3 1 2 1
max 13 9 34 23 19 17 12 8 max 10 9 7 5 5 21
min 0 0 1 1 1 1 1 1 min 0 0 0 0 0 0
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SR-WC 6RC LCO GCO SR BRN HAM
JAN 1 0 0 1 1 3 0 0 1 JAN 0 1 0 1 0 0 1 1 0
FEB 1 7 2 2 4 1 2 1 1 FEB 0 1 1 2 1 3 4 1 1
MAR 3 2 3 3 4 14 3 1 2 MAR 0 5 1 3 1 2 13 3 2
APR 2 2 3 4 13 10 1 0 1 APR 0 2 1 1 1 1 12 2 2
MAY 7 2 3 3 4 4 1 1 4 MAY 0 5 0 1 1 2 10 2 2
JUN 26 1 4 7 20 1 0 1 2 JUN 0 7 1 1 0 1 83 2 1
JUL 5 4 8 3 12 5 1 1 7 JUL 0 35 0 0 0 1 5 6 1
AUG 2 2 29 6 100 16 1 1 14 AUG 2 13 0 0 1 1 34 0 1
SEP 9 2 4 23 26 1 0 0 1 SEP 0 1 1 1 2 1 5 2 5
OCT 7 0 1 2 0 0 0 OCT 0 1 0 1 1 1 5 4 1
NOV 2 1 3 32 3 0 0 1 NOV 3 3 0 21 2 3 8 29 1DEC131225001DEC110126722
mean 6 2 5 5 20 5 1 1 3 mean 1 6 0 3 1 2 16 5 2
std dev 7 2 8 6 29 5 1 1 4 std dev 1 10 1 6 1 2 23 8 1
median 3 2 3 3 12 4 1 1 1 median 0 3 0 1 1 1 8 2 1
max 26 7 29 23 100 16 3 1 14 max 3 35 1 21 2 6 83 29 5
min 1 0 0 1 1 1 0 0 0 min 0 1 0 0 0 0 1 0 0
40
Table 2.16 Fecal Coliform (cfu/100 mL) and Enterococcus (MPN) during 2016 at the Lower Cape Fear River Program stations.
ENTEROCOCCUS
NC11 AC DP IC NCF6 NAV HB BRR M61 M54 M35 M23 M18
JAN 181 19,000 4,000 190 73 64 37 JAN 5 5 52 5 41 134
FEB 100 127 172 37 19 1,180 1,550 FEB 30 169 96 528 1,515 1,106
MAR 10 55 10 546 28 154 118 MAR 75 128 146 145 201 228
APR 109 19 5 64 100 667 570 APR 98 31 52 52 52 63
MAY 55 28 10 82 64 2,400 273 MAY 195 145 85 52 30 341
JUN 28 19 10 37 109 91 73 JUN 52 63 31 20 10 5
JUL 5 10 10 55 28 5 10 JUL 20 10 20 10 5 5
AUG 163 1,270 364 91 190 82 118 AUG 10 41 5 5 5 5
SEP 5 11,000 9,000 4,000 3,400 28,000 16,000 SEP 345 5 5 5 10 209
OCT 340 181 244 154 109 10 28 OCT 5 10 5 94 75 5
NOV 19 5 5 10 55 16,000 2,100 NOV 96 195 300 333 287 836
DEC 82 127 118 8 64 109 DEC 20 5 10 10 5 5
mean 91 2,653 1,162 440 380 4,060 1,749 mean 79 67 67 105 186 245
std dev 95 5,768 2,598 1,083 956 8,416 4,345 std dev 96 69 82 156 410 346
max 340 19,000 9,000 4,000 3,400 28,000 16,000 max 345 195 300 528 1,515 1,106
min 5 5 5 8 19 5 10 min 5 5 5 5 5 5
Geomean 45 129 71 87 89 276 214 Geomean 37 30 31 33 36 52
ANC SAR GS NC403 PB LRC ROC NCF117 SC-CH B210 COL SRWC 6RC LCO GCO SR BRN HAM
JAN 82 127 28 64 2,300 118 199 82 91 JAN 37 73 5 118 28 109 28 145 310
FEB 280 1180 560 190 190 455 1180 163 199 FEB 28 5 163 1,550 55 154 1,360 190 172
MAR 5,300 163 28 37 109 118 127 5,400 1,910 MAR 199 550 172 22,000 320 440 4,100 5,800 2,000
APR 109 118 28 199 145 260 136 10 82 APR 100 250 73 118 2,000 73 199 1,180 440
MAY 340 145 28 210 118 210 410 37 271 MAY 127 118 91 208 46 118 220 530 1,360
JUN 340 163 127 270 46 127 570 28 73 JUN 637 154 82 55 46 100 91 1,460 240
JUL 31,000 637 11,000 109 728 33,000 1,180 1,360 82 JUL 64 136 118 64 37 82 91 728 380
AUG 1,460 637 2,300 819 60,000 2,400 1,910 190 2,700 AUG 154 91 11,000 270 8,000 230 12,000 728 60,000
SEP 16,000 60,000 31,000 44,000 60,000 37,000 21,000 2,400 60,000 SEP 181 819 1,000 2,000 9,000 1,910 7,000 29,000 33,000
OCT 37 64 109 100 145 37 19 OCT 91 19 46 163 73 109 127 270 380
NOV 2,000 11,000 1,550 9,000 8,000 16,000 1,090 2,900 NOV 64 163 55 470 127 260 100 637 790DEC7,000 60,000 728 1,820 4,900 5,800 5,900 118 181 DEC 9,400 32,000 20,000 58,000 62,000 66,000 54,000 38,000 120,000
mean 5,329 11,186 3,957 4,772 12,503 7,299 4,063 910 5,709 mean 924 2,865 2,734 7,085 6,811 5,799 6,610 6,556 18,256
std dev 8,943 22,026 8,673 13,086 22,545 12,657 6,713 1,531 16,402 std dev 2,560 8,788 6,003 16,463 16,923 18,158 14,730 12,276 35,469
max 280 60,000 31,000 44,000 60,000 37,000 21,000 5,400 60,000 max 9,400 32,000 20,000 58,000 62,000 66,000 54,000 38,000 120,000
min 37 64 28 37 46 100 127 10 19 min 28 5 5 55 28 73 28 145 172
Geomean 955 801 357 360 1,143 958 960 190 374 Geomean 153 177 203 554 348 295 621 1,251 1,653
41
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NC11 AC DP IC NAV HB NCF117 NCF6 B210 BRR M61 M54 M35 M23 M18
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Figure 2.6 Geometric Mean Fecal Coliform (NC11-B210) and Enterococcus (BRR-M18) at
the Lower Cape Fear River Program mainstem stations, 1995-2015 (Entero 2012-2014 ) vs.
2016.
1996-2015
2016
42