Lower Cape Fear River Program 2010 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2010
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
August 2011
CMS Report No. 11-02
Center for Marine Science
University of North Carolina Wilmington
Wilmington, N.C. 28409
UNCW Estuarine Biology class 2010 Fish nursery area along Cape Fear
Estuary
Persistent blue-green Microcystis algal
bloom in Cape Fear River, fall 2009
UNCW 2011 River Ecology class
UNCW 2010 Estuarine Biology class
sampling the river plume in waves
The Port of Wilmington
Alligator on the Black River 2011
Executive Summary
Multiparameter water sampling for the Lower Cape Fear River Program (LCFRP) 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 36 water sampling stations throughout the 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 2010. 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 2008-2010) 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 2010 were higher than the average for 1995-2009. 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 M42 to M18. Lowest mainstem average 2010 DO levels occurred at
the lower river and upper estuary stations DP, IC, NAV, HB, BRR and M61 (7.2-7.6
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 often seems to be more oxygen stressed than the Black River; as such, in 2010 Stations NCF117 and B210,
representing those rivers, had average DO concentrations of 6.7 and 7.0 mg/L, respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2010. Station BCRR (upper Burgaw Creek) had DO levels
below 4.0 mg/L 67% of the occasions sampled, with SR (South River) and GS (Goshen
Swamp) 50%, LVC2 (Livingston Creek) 45%, ANC (Angola Creek) 42% and NC403 (Northeast Cape Fear River headwaters) 33%. Considering all sites sampled in 2010, we rated 22% as poor for dissolved oxygen, 22% as fair, and 56% as good, a worsening
from 2009
Annual mean turbidity levels for 2010 were lower than the long-term average in most stations, with the exception of the mid-estuary sites M42-M35. Highest mean turbidities were at the river sites NC11 (21 NTU) and AC and DP (22 NTU) followed by the upper
estuary sites NAV, HB, BRR, M54 and M42 (17 NTU), with turbidities gradually
decreasing downstream through the estuary. Turbidity was much lower in the
blackwater tributaries (Northeast Cape Fear River and Black River) than in the mainstem river, and were low in general in the lower order streams.
Regarding stream stations, chronic or periodic high nitrate levels were found at a
number of sites, including BC117 (Burgaw Creek below Burgaw), ROC (Rockfish
Creek), LRC (Little Rockfish Creek), 6RC (Six Runs Creek), NC403, and PB (Panther Branch). Average chlorophyll a concentrations were larger than usual, particularly from
June through August 2010; during this same period river flow as measured by USGS at
Lock and Dam #1 was lower for 2010 compared with the 1995-2009 long-term average
(1,769 CFS compared with 3,702 CFS). Low discharge allows for settling of suspended
solids and more light penetration into the water column, where the relatively high nutrient levels and slow moving waters support algal bloom formation. In the estuary a substantial bloom (76 µg/L) occurred at M42, and stream algal blooms exceeding the
State standard of 40 µg/L in 2010 occurred at ANC, GS, PB and SR. The most
troublesome occurrence was the recurrence of cyanobacteria (i.e. blue-green algal
blooms) in the Cape Fear River during summer centered in the river near NC11. These consisted largely of Microcystis aeruginosa, which can produce toxins, and their
persistence and concentrations was the greatest seen in this section of the river during
the length of the Lower Cape Fear River Program. We note that fish kills were not
reported related to the blooms.
Several stream stations, particularly BC117, BCRR, PB, BRN (Browns Creek), HAM (Hammond Creek), SAR (Northeast Cape Fear River near Sarecta), LCO, 6RC and
LRC showed high fecal coliform bacteria counts on a number of occasions. On rare
occasions biochemical oxygen demand (BOD) concentrations at a few Cape Fear River
watershed stations (NC11, NCF117 and LVC2 were elevated (BOD5 3.0 mg/L or greater). Collection of water column metals was suspended in early 2007 as they are no longer required by NC DWQ.
This report also includes an in-depth look at each subbasin, providing information
regarding the results of the North Carolina Division of Water Quality's 2005 Basinwide Management Plan, and providing the UNCW-Aquatic Ecology Laboratory’s (AEL)
assessments of the 2010 sampling year. The UNCW-AEL utilizes ratings that consider a water body to be of poor quality if the water quality standard for a given parameter is
in violation > 25% of the time, of fair quality if the standard is in violation between 11
and 25% of the time, and good quality if the standard is violated no more than 10% of
the time. UNCW also considerers nutrient loading in water quality assessments, based on published experimental and field scientific findings.
For the 2010 period UNCW rated 94% of the stations as good and 6% fair in terms of
chlorophyll a. For turbidity 86% of the sites were rated good and 14% fair (all located in
the upper estuary). Fecal coliform bacteria counts showed slightly worse water quality in 2010 compared to 2009, with 43% of the sites rated as poor to fair compared with 40% in 2009. Using the 5.0 mg/L DO standard for the mainstem river stations, and the
4.0 mg/L “swamp water” DO standard for the stream stations and blackwater river
stations, 44% of the sites were rated poor or fair for dissolved oxygen, somewhat higher
than in 2009. In addition, by our UNCW standards excessive nitrate and phosphorus concentrations were problematic at a number of stations (Chapter 3).
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………………………………………………..…………………….....….. ….8 Physical Parameters..…......................………..........................................……....11
Chemical Parameters…....……..……….........................................................…..14
Biological Parameters.......……….....……......................................................…..17
3.0 Water Quality by Subbasin in the Lower Cape Fear River System…………………45
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 2010.
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
15-year (1995-2010) 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 pollution episodes. The scientific aspects of the program are carried out by investigators from the University of North Carolina Wilmington Center for Marine Science. The monitoring
program was developed by the Lower Cape Fear River Program Technical Committee,
which consists of representatives from UNCW, the North Carolina Division of Water
Quality, The NC Division of Marine Fisheries, the US Army Corps of Engineers, technical representatives from streamside industries, the City of Wilmington Wastewater Treatment Plants, 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. 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 funding. The third major biotic component (added in January 1996) was an extensive
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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 9,149 square miles) is the most heavily industrialized in North
Carolina with 244 permitted wastewater discharges with a permitted flow of approximately 425 million gallons per day, and (as of 2000) over 1.83 million people residing in the basin (NCDENR 2005). Approximately 24% of the land use in the
watershed is devoted to agriculture and livestock production (NCDENR 2005), 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 nine 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). 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 stations throughout the Cape Fear, Northeast Cape Fear, and Black River watersheds (Table 1.1; Fig. 1.1; Mallin et al. 2001). Data
collection at a station in the Atlantic Intracoastal Waterway was initiated in February
1998 to obtain water quality information near the Southport Wastewater Treatment Plant
discharge, and there is one station, SC-CH, sampled for selected parameters on Smith Creek at Castle Hayne Road (Table 1.1).
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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 36 individual
stations, and provides tables of raw data as well as figures showing spatial or temporal
trends. In Section 3 we analyze our data by sub-basin, give information regarding the NC DWQ's 2005 Basinwide Plan, and make UNCW-based water quality ratings for dissolved oxygen, turbidity, chlorophyll a, and fecal coliform bacterial abundance. We
also utilize other relevant parameters such as nutrient concentrations to aid in these
assessments. This section is designed so that residents of a particular sub-basin can
see what the water quality is like in his or her area based on LCFRP data collections. 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/cmsr/aquaticecology/lcfrp/
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 Natural Resources, Division of Water Quality/Planning, Raleigh, NC, 27699-1617.
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Table 1.1. Description of sampling locations in the Cape Fear Watershed, 2010, including UNCW designation and NCDWQ station designation number.
________________________________________________________________
UNCW St. DWQ No. Location ________________________________________________________________
High order river and estuary stations
NC11 B8360000 At NC 11 bridge on Cape Fear River (CFR) GPS N 34.39663 W 78.26785
AC B8450000 5 km downstream from International Paper on CFR
GPS N 34.35547 W 78.17942
DP B8460000 At DAK America’s Intake above Black River GPS N 34.33595 W 78.05337
IC B9030000 Cluster of dischargers upstream of Indian Cr. on CFR
GPS N 34.30207 W 78.01372 B210 B9000000 Black River at Highway 210 bridge
GPS N 34.43138 W 78.14462
BBT none Black River between Thoroughfare and Cape Fear River GPS N 34.35092 W 78.04857
NCF117 B9580000 Northeast Cape Fear River at Highway 117, Castle Hayne
GPS N 34.36342 W 77.89678
NCF6 B9670000 Northeast Cape Fear River near GE dock GPS N 34.31710 W 77.95383
NAV B9050000 Railroad bridge over Cape Fear River at Navassa
GPS N 34.25943 W 77.98767 HB B9050100 Cape Fear River at Horseshoe Bend
GPS N 34.24372 W 77.96980
BRR B9790000 Brunswick River at John Long Park in Belville GPS N 34.22138 W 77.97868
M61 B9750000 Channel Marker 61, downtown at N.C. State Port
GPS N 34.19377 W 77.95725
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M54 B7950000 Channel Marker 54, 5 km downstream of Wilmington GPS N 34.13933 W 77.94595
M42 B9845100 Channel Marker 42 near Keg Island
GPS N 34.09017 W 77.93355 M35 B9850100 Channel Marker 35 near Olde Brunswick Towne
GPS N 34.03408 W 77.93943
M23 B9910000 Channel Marker 23 near CP&L intake canal GPS N 33.94560 W 77.96958
M18 B9921000 Channel Marker 18 near Southport
GPS N 33.91297 W 78.01697
SPD B9980000 1000 ft W of Southport WWT plant discharge on ICW GPS N 33.91708 W 78.03717
________________________________________________________________
Stream stations collected from land ________________________________________________________________
SR B8470000 South River at US 13, below Dunn
GPS N 35.15600 W 78.64013
GCO B8604000 Great Coharie Creek at SR 1214 GPS N 34.91857 W 78.38873
LCO B8610001 Little Coharie Creek at SR 1207
GPS N 34.83473 W 78.37087 6RC B8740000 Six Runs Creek at SR 1003 (Lisbon Rd.)
GPS N 34.79357 W 78.31192
BRN B8340050 Browns Creek at NC 87 GPS N 34.61360 W 78.58462
HAM B8340200 Hammonds Creek at SR 1704
GPS N 34.56853 W 78.55147
LVC2 B8441000 on Livingston Creek near Acme GPS N 34.33530 W 78.2011
COL B8981000 Colly Creek at NC 53
GPS N 34.46500 W 78.26553
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ANC B9490000 Angola Creek at NC 53
GPS N 34.65705 W 77.73485
NC403 B9090000 Northeast Cape Fear below Mt. Olive Pickle at NC403 GPS N 35.17838 W 77.98028
PB B9130000 Panther Branch below Bay Valley Foods
GPS N 35.13445 W 78.13630
GS B9191000 Goshen Swamp at NC 11 GPS N 35.02923 W 77.85143
SAR B9191500 Northeast Cape Fear River near Sarecta
GPS N 34.97970 W 77.86251 LRC B9460000 Little Rockfish Creek at NC 11
GPS N 34.72247 W 77.98145
ROC B9430000 Rockfish Creek at US 117 GPS N 34.71689 W 77.97961
BCRR B9500000 Burgaw Canal at Wright St., above WWTP
GPS N 34.56334 W 77.93481
BC117 B9520000 Burgaw Canal at US 117, below WWTP GPS N 34.56391 W 77.92210
SC-CH B9720000 Smith Creek at Castle Hayne Rd.
GPS N 34.25897 W 77.93872
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Figure 1.1 Map of the Lower Cape Fear River system and the LCFRP sampling stations.
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2.0 Physical, Chemical, and Biological Characteristics of the
Lower Cape Fear River and Estuary
Michael A. Mallin and Matthew R. McIver Aquatic Ecology Laboratory Center for Marine Science
University of North Carolina Wilmington
2.1 - Introduction This section of the report includes a discussion of the physical, chemical, and biological
water quality parameters, concentrating on the January-December 2010 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. Three biological parameters
including fecal coliform bacteria, chlorophyll a and biochemical oxygen demand 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. We note that our previous Livingston Creek station (LVC) has
been discontinued and a new station sampled from the dock of Hexion Specialty
Chemicals near Acme (LVC2) was put into operation in 2005. Physical Parameters
Water Temperature, pH, Dissolved Oxygen, Turbidity, Salinity, Conductivity
Field parameters 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, the middle of the water column, and at the bottom
(up to 12 m). Occasionally, high flow prohibited the sonde from reaching the actual bottom and measurements were taken as deep as possible. At the terrestrially sampled stations
8
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.
Chemical Parameters Nutrients
All nutrient analyses were performed at the UNCW Center for Marine Science (CMS) for
samples collected prior to January 1996. A local State-certified analytical laboratory was contracted to conduct all subsequent 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
Fecal coliform bacteria were analyzed at 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.
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
9
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.
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. The procedure used for BOD analysis was
Method 5210 in Standard Methods (APHA 1995). Samples were analyzed for both 5-day and 20-day BOD. During the analytical period, samples were kept in airtight bottles and placed in an incubator at 20o C. All experiments were initiated within 6 hours of sample
collection. Samples were analyzed in duplicate. Dissolved oxygen measurements were
made using a YSI Model 5000 meter that was air-calibrated. No adjustments were made
for pH since most samples exhibited pH values within or very close to the desired 6.5-7.5 range (pH is monitored during the analysis as well); a few sites have naturally low pH and there was no adjustment for these samples because it would alter the natural water
chemistry and affect true BOD. Data are presented within for the five original sites.
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 2010. 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 did not
experience any significant hurricane activity during this monitoring period (after major
hurricanes in 1996, 1998, and 1999). Therefore this report reflects low to medium flow
conditions for the Cape Fear River and Estuary.
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Physical Parameters
Water temperature
Water temperatures at all stations ranged from 3.7 to 31.3oC, and individual station annual averages ranged from 15.9 to 21.3oC (Table 2.1). Highest temperatures occurred during July and August and lowest temperatures during January. 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 SPD) ranged from 0.0 to 35.0 practical
salinity units (psu) and station annual means ranged from 2.4 to 25.9 psu (Table 2.2).
Lowest salinities occurred in February and October and highest salinities occurred in September. The annual mean salinity for 2010 was higher than that of the fourteen-year average for 1996-2009 for the upper through middle estuary stations, and equal to or less
than the long-term mean for the lower 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 ranges widely, from freshwater to salinity exceeding 20 psu.
Conductivity
Conductivity at the estuarine stations ranged from 0.09 to 53.20 mS/cm and from 0.06 to 10.70 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. Conductivity may also reveal point source pollution sources, as
is seen at BC117, which is below a municipal wastewater discharge. 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 3.8 to 8.3 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 are 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; 2001a; 2001b; 2002a; 2002b; 2003; 2004; 2005a; 2006a; 2006b; 2007; 2008; 2009; 2010).
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Surface concentrations for all sites in 2010 ranged from 0.3 to 17.5 mg/L and station annual means ranged from 3.8 to 10.4 mg/L (Table 2.5). Average annual DO levels at the
river channel and estuarine stations for 2010 were higher than the average for 1996-2009
(Figure 2.2). River dissolved oxygen levels were lowest during the summer and early fall
(Table 2.5), often falling below the state standard of 5.0 mg/L at several river and upper estuary stations. 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 2010 DO levels occurred
at the river and upper estuary stations IC, NAV, HB, BRR and M61 (7.2-7.6 mg/L). NAV
and BRR were both below 5.0 mg/L on 33% of occasions sampled and BRR, HB and IC was below on 25%, an improvement from 2009. Based on number of occasions the river stations were below 5 mg/L UNCW rated NAV, IC and BRR as poor for 2010, and DP, HB,
M61 and M54 as fair for 2010; the mid to lower estuary stations were rated as good.
Discharge of high 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, and the chlorophyll a they produce is strongly
correlated with BOD at Station NC11 (Mallin et al. 2006b); 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.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River (NCF117 2010 mean = 6.7, NCF6 = 6.8, B210 2010 mean =
7.0). 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.
2006b).
In the past the Northeast Cape Fear River has often been more oxygen stressed than the Black River, and in 2010 Stations NCF117 DO concentrations were again somewhat lower
12
than at B210 (means 6.7 and 7.0 mg/L, respectively). Several stream stations were severely stressed in terms of low dissolved oxygen during the year 2010. Station BCRR
had DO levels below 4.0 mg/L 67% of the occasions sampled, with SR and GS 50%, LVC2
45%, ANC 42% and NC403 33% (Table 2.5). Some of this can be attributed to low
summer water conditions and some potentially to CAFO runoff; however point-source discharges also likely contribute to low dissolved oxygen levels at NC403 and possibly SR, especially via nutrient loading (Mallin et al. 2001a; 2002a; 2004). Hypoxia is thus a
continuing widespread problem, with 44% of the sites impacted in 2010.
Field Turbidity Field turbidity levels ranged from 0 to 122 Nephelometric turbidity units (NTU) and station
annual means ranged from 2 to 22 NTU (Table 2.6). The State standard for estuarine
turbidity is 25 NTU. Annual mean turbidity levels for 2010 were lower than the long-term
average in most stations, with the exception of the mid-estuary sites M42-M35 (Fig. 2.3). Highest mean and median turbidities were at AC, DP and NC11 (21-22 NTU) with turbidities generally low in the middle to lower estuary (Figure 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 BCRR and to a lesser extent BRN and BC117. The State standard for freshwater turbidity is 50 NTU.
Note: In addition to the laboratory-analyzed turbidity that are required my 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
Total suspended solid (TSS) values system wide ranged from 1 to 118 mg/L with station annual means from 2 to 20 mg/L (Table 2.7). The overall highest river values were at M42, M54, AC and DP. In the stream stations TSS was generally considerably lower than
the river and estuary, except for Station BCRR. Although total suspended solids (TSS)
and turbidity both quantify suspended material in the water column, they do not always go
hand in hand. High TSS does not mean high turbidity and vice versa. This anomaly may be explained by the fact that fine clay particles are effective at dispersing light and causing high turbidity readings, while not resulting in high TSS. On the other hand, large organic or
inorganic particles may be less effective at dispersing light, yet their greater mass results
in high TSS levels. While there is no NC ambient standard for TSS, many years of data
from the lower Cape Fear watershed indicates that 25 mg/L can be considered elevated.
13
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 (through absorbance or reflection) in the water column. River and estuary light attenuation coefficients ranged from 0.87 to 7.39/m and station annual means ranged
from 1.64 at M18 to 3.86 /m at NCF6 (Table 2.8). Elevated mean and median light
attenuation persisted from NC11 downstream to IC; the estuary from M61-M42 also had
high attenuation (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 high average 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). 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 120 to 30,000 µg/L and station annual means ranged from
415 to 14,383 µg/L (Table 2.9). Mean total nitrogen in 2010 was slightly less than the
fourteen-year mean at most river and estuary stations (Figure 2.4). 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 between NC11
and AC, entering the system, then remained fairly constant down the river and declined
from mid-estuary 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. One stream station, BC117, had a very high
median of 16,100 µg/L, likely from the upstream Town of Burgaw wastewater discharge.
PB, ROC, LRC, NC403 and 6RC also had comparatively high TN values among the
stream stations.
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 30,000 µg/L and station annual means ranged from 97 to 14,008 µg/L (Table 2.10). The
highest average riverine nitrate levels were at NC11 and AC (743 and 715 µg/L,
respectively) indicating that much of this nutrient is imported from upstream. Moving
14
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. 2005b). Nitrate can
limit phytoplankton production in the lower estuary in summer (Mallin et al. 1999). The blackwater rivers carried lower loads of nitrate compared to the mainstem Cape Fear
stations; i.e. the Northeast Cape Fear River (NCF117 mean = 402 µg/L) and the Black
River (B210 = 328 µg/L). Lowest river nitrate occurred during summer, along with lowest
flows and lowest dissolved oxygen concentrations. Several stream stations showed high levels of nitrate on occasion including BC117, ROC,
LRC, 6RC and NC403. NC403 is downstream of industrial wastewater discharges and
ROC, LRC and 6RC primarily receive non-point agricultural or animal waste drainage.
BC117 always showed very high nitrate levels. The Town of Burgaw wastewater plant, upstream of BC117, has no nitrate discharge limits. 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 0.2 to 0.5 mg/L as N
(Mallin et al. 1998; Mallin et al. 2001a; Mallin et al. 2002a, Mallin et al. 2004). Thus, we
conservatively consider nitrate concentrations exceeding 0.5 mg/L as N in Cape Fear
watershed streams to be potentially problematic to the stream’s environmental health.
Ammonium
Ammonium concentrations ranged from 5 (detection limit) to 930 µg/L and station annual
means ranged from 12 to 268 µg/L (Table 2.11). River areas with the highest mean ammonium levels this monitoring period included AC, which is below a pulp mill discharge,
and M54, located downstream of the Wilmington South Side Wastewater Treatment Plant
discharge. Ocean dilution and biological uptake accounts for decreasing levels in the
lower estuary. At the stream stations, areas with highest levels of ammonium were BCRR, PB and LVC2, which had the highest mean and median ammonium concentrations in the system (Table 2.11).
Total Kjeldahl Nitrogen
Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen
plus ammonium. TKN ranged from 100 to 2,800 µg/L and station annual means ranged
from 273 to 1,217 µg/L (Table 2.12). TKN concentration decreases ocean-ward through
the estuary, likely due to ocean dilution and food chain uptake of nitrogen. One notably elevated peak of 2,800 µg/L of TN was seen at BCRR in May. Station ANC had the highest mean and median concentrations; other sites with elevated TKN included PB,
COL, BCRR and ROC.
15
Total Phosphorus
Total phosphorus (TP) concentrations ranged from below detection limit to 3,780 µg/L and
station annual means ranged from 23 to 1,668 µg/L (Table 2.13). Mean TP for 2010 was approximately equal to the fourteen-year mean in the majority of the stations (Figure 2.5). In the river TP is highest at the upper riverine channel stations and declines 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 0.5 mg/L led to significant
increases in bacterial counts, as well as significant increases in BOD over control. Thus,
we consider concentrations of phosphorus above 0.5 mg/L (500 µg/L ) to be potentially
problematic to blackwater streams. Streams periodically exceeding this critical
concentration included BC117, GCO, ROC, PB and BCRR. Some of these stations
(BC117, PB) are downstream of industrial or wastewater discharges, while GCO, BCRR
and ROC are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 2,940 µg/L and station annual means ranged
from 6 to 1,484 µg/L (Table 2.14). Much of the 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).
The stream station BC117 had very high orthophosphate levels, and ROC and GCO had
comparatively high levels. BC117 is below a municipal wastewater discharge, and ROC,
and GCO are impacted by agriculture/animal waste runoff.
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.
Biological Parameters Chlorophyll a
During this monitoring period in most locations chlorophyll a was low, except for periodic
elevated concentrations from May – September at a few locations (Table 2.15). At many of the river and estuarine stations chlorophyll a for 2010 was considerably higher than the
fourteen-year mean for those sites (Figure 2.6). Algal blooms occurred in July and August
at Station NC11, with chlorophyll a levels of 39-47 µg/L. We note that at this site it has
been demonstrated that chlorophyll a biomass is significantly correlated with biochemical
oxygen demand (BOD5 – Mallin et al. 2006b). What was of human health as well as ecological interest was that blooms of cyanobacteria (blue-green algae) called Microcystis
aeruginosa that began occurring in 2009 continued to occur in summer 2010. These
blooms are primarily a surface phenomenon. UNCW sampled chlorophyll a July 15th and
got high values, with a surface Microcystis bloom at NC11 yielding 364 ppb, subsurface at
NC11 yielding 41 ppb, and subsurface at Lock and Dam 1 yielding 28 ppb. The bloom persisted for a number of weeks before dissipating. The presence of the bloom affected
Brunswick County water treatment in 2009 and they contracted with UNCW LCFRP to
collect periodic additional water samples to keep them informed of chlorophyll a
concentrations. We note that the City of Wilmington also receives their drinking water from
the river above Lock and Dam #1.
System wide, chlorophyll a ranged from undetectable to 217 µg/L and station annual
means ranged from 1–36 µg/L, lower than in 2009. 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 and high organic color and low inorganic nutrients in the
blackwater 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 (Table 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 (1995-2009) average monthly flow at Lock and
Dam #1 was 3,704 CFS (USGS data;
17
(http://nc.water.usgs.gov/realtime/real_time_cape_fear.html), whereas for 2010 it was well below that at 1,769 CFS. Thus, chlorophyll a concentrations in the river and estuary were
larger than the average for the preceding eleven years (Figure 2.6).
Substantial phytoplankton blooms occasionally occur at the stream stations, with a few occurring late spring and summer in 2010 (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. Thus, when lower flow conditions prevail,
elevated nutrient conditions (such as are periodically found in these stream stations) can
lead to algal blooms. 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. 2001a; 2002a; 2004; 2006b). Stream algal blooms exceeding the
State standard of 40 µg/L in 2010 occurred at ANC, GS, PB and SR (Table 2.15).
Biochemical Oxygen Demand
For the mainstem river, median annual five-day biochemical oxygen demand (BOD5)
concentrations were approximately equivalent between NC11 and AC, suggesting that in
2010 (as was the case with 2007 through 2009) there as little discernable effect of BOD loading from the nearby pulp/paper mill inputs (Table 2.16). BOD5 values between 1.0 and 2.0 mg/L are typical for the rivers in the Cape Fear system (Mallin et al. 2006b) and in
2010 the highest value seen was 3.3 mg/L at NCF117, indicating there was no significant
BOD problem in 2010. Stations LVC2 and AC had the highest mean and median BOD5
and BOD20 concentrations in 2010. Fecal Coliform Bacteria
Fecal coliform (FC) bacterial counts ranged from 5 to 23,000 CFU/100 mL and station
annual geometric means ranged from 7 to 483 CFU/100 mL (Table 2.17). The state human contact standard (200 CFU/100 mL) was exceeded at the mainstem sites only rarely in 2010, once in October at M42 and once in July at AC. Geometric mean fecal
coliform counts in 2010 in the Cape Fear, Black, and Northeast Cape Fear Rivers as well
as the estuary were mixed compared with the fourteen-year average (Figure 2.7).
During 2010 BRN exceeded the state standard 75% of the time; BC117 67%, PB 50%, BCRR and HAM 58%, LRC, LCO and SR 33%, SAR, NC403 and GCO 25%, and GS and
SC-CH 17% of the time. BC117, NC403 and PB are located below point source
discharges and the other sites are primarily influenced by non-point source pollution.
Overall, elevated fecal coliform counts are problematic in this system, with 43% of the stations impacted in 2010, slightly higher than the previous year 2009.
2.4 - References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed. American Public Health Association, Washington, D.C.
18
Burkholder. J.M. 2002. Cyanobacteria. In “Encyclopedia of Environmental Microbiology” (G. Bitton, Ed.), pp 952-982. Wiley Publishers, New York. 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. 2000. Impacts of industrial-scale swine and poultry production on rivers and
estuaries. American Scientist 88:26-37.
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. 2001a. Effect of nitrogen and phosphorus loading on plankton in Coastal Plain blackwater streams. Journal of
Freshwater Ecology 16:455-466.
Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S. Williams, M.L. Moser and J.F. Merritt. 2001b. Environmental Assessment of the Lower
Cape Fear River System, 2000-2001. CMS Report No. 01-01, Center for Marine
Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002a. 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.
19
Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, H.A. CoVan, T.D. Alphin, M.S. Williams and J.F. Merritt. 2002b. Environmental Assessment of the Lower Cape Fear
River System, 2001-2002. CMS Report No. 02-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver, H.A. Wells, M.S. Williams, T.E. Lankford and J.F. Merritt. 2003. Environmental Assessment of the Lower Cape Fear River System, 2002-2003. CMS
Report No. 03-03, Center for Marine Science, University of North Carolina at
Wilmington, Wilmington, 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., M.R. McIver, T.D. Alphin, M.H. Posey and J.F. Merritt. 2005a. Environmental Assessment of the Lower Cape Fear River System, 2003-2004. CMS Report No. 05-02, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C. Mallin, M.A., L.B. Cahoon and M.J. Durako. 2005b. 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., M.R. McIver and J.F. Merritt. 2006a. Environmental Assessment of the Lower Cape Fear River System, 2005. CMS Report No. 06-02, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., V.L. Johnson, S.H. Ensign and T.A. MacPherson. 2006b. Factors contributing
to hypoxia in rivers, lakes and streams. Limnology and Oceanography 51:690-701.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2007. Environmental Assessment of the Lower
Cape Fear River System, 2006. CMS Report No. 07-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2008. Environmental Assessment of the Lower Cape Fear River System, 2007. CMS Report No. 08-03, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2009. Environmental Assessment of the Lower
Cape Fear River System, 2008. CMS Report No. 09-06, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2010. Environmental Assessment of the Lower
Cape Fear River System, 2009. CMS Report No. 10-04, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C. 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
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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.
21
Table 2.1 Water temperature (oC) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 3.2 3.3 3.6 4.4 4.3 4.6 5.0 6.0 5.9 5.4 JAN 4.4 4.5 4.4 2.7 3.5 3.1
FEB 5.2 5.3 5.3 5.6 5.8 5.7 6.3 6.7 7.9 6.7 FEB 5.2 5.3 5.5 5.2 5.2 5.8
MAR 9.0 9.2 8.9 9.3 9.5 9.3 9.5 10.3 9.7 10.5 MAR 14.1 14.0 14.1 14.6 14.2 14.9
APR 20.1 20.4 20.4 21.4 20.3 20.5 20.1 19.3 18.4 18.6 APR 18.6 18.8 18.8 20.8 19.6 20.7
MAY 24.5 27.3 24.7 24.3 24.3 24.5 23.9 22.8 22.4 23.1 MAY 23.5 23.7 24.0 24.6 24.6 24.5
JUN 27.7 28.0 27.9 27.9 27.6 27.2 27.4 27.6 27.6 28.9 JUN 25.6 25.7 25.6 24.8 25.3 26.4
JUL 30.6 31.1 31.2 30.4 29.9 29.2 29.1 28.3 28.2 29.2 JUL 30.3 30.3 30.1 27.9 29.2 30.8
AUG 30.6 30.7 31.3 30.9 30.6 30.1 29.8 29.3 28.8 29.6 AUG 30.7 31.1 31.0 30.4 30.8 30.8
SEP 28.8 29.2 28.7 29.3 28.9 28.9 28.9 28.2 28.2 28.1 SEP 28.7 28.5 28.0 28.0 28.3 28.6
OCT 19.1 19.3 20.1 20.0 20.3 20.4 20.3 OCT 19.4 19.2 19.3 18.6 18.9 19.4
NOV 13.8 14.4 15.0 15.5 15.8 16.0 16.2 16.4 16.5 16.6 NOV 13.8 14.4 14.1 12.8 13.4 14.4
DEC 6.4 6.9 7.2 7.6 6.5 8.8 8.7 8.6 10.3 8.7 DEC 9.0 8.9 8.2 8.1 8.9 9.9
mean 19.6 20.2 20.1 20.2 20.0 20.1 20.0 19.8 19.8 20.0 mean 19.9 20.0 19.9 19.6 19.9 20.6
std dev 9.7 9.9 9.7 9.4 9.4 8.9 8.8 8.8 8.4 9.1 std dev 8.7 8.7 8.7 8.5 8.6 8.5
median 19.6 19.9 20.3 20.7 20.3 20.5 20.2 19.3 18.4 18.6 median 19.0 19.0 19.1 19.7 19.3 20.1
max 30.6 31.1 31.3 30.9 30.6 30.1 29.8 29.3 28.8 29.6 max 30.7 31.1 31.0 30.4 30.8 30.8
min 5.2 5.3 5.3 5.6 5.8 5.7 6.3 6.7 7.9 6.7 min 5.2 5.3 5.5 5.2 5.2 5.8
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 4.7 1.8 2.8 3.1 3.5 2.4 3.7 3.3 JAN 1.6 1.0 0.1 0.3 2.1 2.4 JAN 7.8 8.1 7.4 10.4 6.9
FEB 8.9 5.1 6.7 5.7 6.2 5.8 5.6 7.2 6.8 FEB 5.7 5.4 5.4 5.4 6.5 6.4 FEB 6.2 5.5 4.1 7.1
MAR 12.7 13.5 14.6 13.7 13.5 13.5 12.4 11.0 9.9 MAR 7.5 7.3 6.7 7.0 7.5 7.2 MAR 7.5 6.8 6.0 7.0 7.9
APR 17.3 15.6 16.7 17.7 16.3 14.5 14.8 14.6 14.3 APR 19.9 19.9 20.7 21.0 19.8 19.0 APR 20.1 20.8 19.9 19.8 21.0
MAY 21.5 22.1 22.9 21.4 21.9 19.9 21.9 20.7 20.1 MAY 23.2 23.3 24.3 21.9 21.6 20.6 MAY 23.6 23.8 21.4 22.0 25.2
JUN 23.1 24.1 24.7 25.9 24.1 23.0 23.3 22.9 23.2 JUN 23.5 23.1 23.9 23.4 22.6 20.8 JUN 30.0 29.3 26.4 27.9 29.6
JUL 25.5 28.3 29.0 27.5 28.0 27.5 26.8 26.4 24.4 JUL 25.0 26.0 26.5 25.1 24.9 25.3 JUL 29.8 24.9 22.4 26.1 29.4
AUG 25.0 24.8 25.3 25.7 25.6 24.6 24.4 24.0 AUG 25.6 25.6 25.5 24.9 24.7 24.5 AUG 30.0 29.2 25.0 27.8 30.8
SEP 26.7 26.1 24.5 26.1 27.9 25.2 24.7 25.0 23.6 SEP 21.3 22.0 22.8 21.2 20.8 SEP 27.8 26.3 23.5 26.0 29.0
OCT 16.1 15.5 15.7 16.4 16.0 15.5 15.4 17.9 15.7 OCT 19.1 18.7 18.8 19.1 18.1 17.6 OCT 19.4 19.3 18.6 19.8 21.8
NOV 9.1 8.6 8.1 9.1 7.3 8.4 9.3 11.5 9.9 NOV 14.4 14.6 14.7 14.4 14.9 14.5 NOV 18.0 15.2 13.6 15.2 18.7
DEC 6.0 5.1 4.6 4.8 3.7 5.2 5.9 6.6 8.3 DEC 12.8 12.9 13.7 13.4 14.5 12.3 DEC 13.4 12.3 9.7 11.8 14.1
mean 17.4 17.2 17.5 17.6 17.3 15.9 16.8 17.1 16.4 mean 17.7 18.0 18.4 18.0 17.8 17.2 mean 20.5 19.4 17.3 20.3 21.3
std dev 7.4 8.5 8.4 8.4 8.9 7.9 7.9 7.3 6.9 std dev 7.2 7.1 7.4 7.0 6.4 6.4 std dev 8.7 8.4 7.8 7.1 8.6
median 16.7 15.6 16.2 17.1 16.3 14.5 15.1 16.3 15.0 median 19.1 19.3 19.8 20.1 19.0 18.3 median 19.8 20.1 19.3 19.8 21.4
max 26.7 28.3 29.0 27.5 28.0 27.5 26.8 26.4 24.4 max 25.6 26.0 26.5 25.1 24.9 25.3 max 30.0 29.3 26.4 27.9 30.8
min 6.0 5.1 4.6 4.8 3.7 5.2 5.6 6.6 6.8 min 5.7 5.4 5.4 5.4 6.5 6.4 min 6.2 5.5 4.1 7.0 7.1
22
Table 2.2 Salinity (psu) during 2010 at the Lower Cape Fear River Program estuarine stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6 SC-CH
JAN 0.1 0.5 0.7 4.9 5.3 7.2 10.8 17.7 19.6 22.6 0.1 0.1
FEB 0.0 0.0 0.0 0.1 0.1 0.1 1.2 6.3 20.6 7.0 0.0 0.1
MAR 0.1 0.1 0.1 1.1 1.8 2.9 3.8 13.6 14.7 18.4 0.1 0.1
APR 0.1 1.0 0.7 2.7 5.3 8.0 12.9 17.9 24.8 21.7 0.1 0.3
MAY 5.4 7.1 10.1 13.9 16.4 19.2 23.7 29.0 31.7 30.3 1.2 3.2
JUN 0.1 0.1 0.1 3.0 3.9 4.6 6.3 14.4 16.7 22.7 5.5 6.7
JUL 1.1 2.9 5.5 12.5 14.9 16.6 19.3 25.0 26.7 30.7 3.5 7.4
AUG 7.0 7.6 9.6 16.0 18.3 20.8 24.8 30.6 33.0 30.5 17.2 12.0
SEP 13.8 12.5 16.1 17.5 21.2 23.8 27.9 33.9 35.0 32.9 15.6 6.3
OCT 0.1 0.1 0.1 0.1 0.2 0.7 1.6 0.0 0.3
NOV 0.1 2.8 6.0 11.1 13.7 16.4 18.5 25.5 27.8 31.0 0.1 6.3
DEC 0.9 3.9 6.4 11.5 13.2 23.7 25.2 29.1 33.9 29.7 9.5 4.5
mean 2.4 3.2 4.6 7.9 9.5 12.0 14.7 22.1 25.9 25.2 4.4 3.9
std dev 4.3 4.0 5.3 6.5 7.5 9.0 9.8 8.6 7.2 7.7 6.3 3.9
median 0.1 1.9 3.1 8.0 9.3 12.2 15.7 25.0 26.7 29.7 0.7 3.9
max 13.8 12.5 16.1 17.5 21.2 23.8 27.9 33.9 35.0 32.9 17.2 12.0
min 0.0 0.0 0.0 0.1 0.1 0.1 1.2 6.3 14.7 7.0 0.0 0.1
23
0
5
10
15
20
25
30
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6
Sa
l
i
n
i
t
y
(
P
S
U
)
Figure 2.1 Salinity at the Lower Cape Fear River Program estuarine stations,
1995-2009 versus 2010.
1995-2009
2010
24
Table 2.3 Conductivity (mS/cm) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 0.14 1.02 1.47 8.90 9.60 12.61 18.38 29.01 31.93 36.35 JAN 0.12 0.14 0.13 0.09 0.11 0.13
FEB 0.09 0.09 0.09 0.10 0.10 0.22 2.28 11.12 33.11 12.28 FEB 0.10 0.11 0.11 0.08 0.09 0.09
MAR 0.11 0.11 0.12 2.16 3.41 5.35 6.88 22.52 24.06 29.80 MAR 0.10 0.13 0.12 0.08 0.11 0.12
APR 0.13 1.86 1.47 5.05 9.33 13.71 21.45 29.08 38.91 34.38 APR 0.10 0.11 0.11 0.09 0.10 0.15
MAY 9.57 12.25 17.13 22.96 26.81 30.91 37.42 44.75 48.48 46.53 MAY 0.12 0.14 0.23 0.14 0.19 2.32
JUN 0.13 0.15 0.17 5.49 7.06 8.39 11.09 23.82 27.36 36.05 JUN 0.13 0.15 0.15 0.11 0.13 9.87
JUL 2.22 5.40 9.78 20.97 24.67 27.12 31.13 39.32 41.73 47.30 JUL 0.11 0.27 0.24 0.10 0.16 6.43
AUG 12.13 13.41 16.45 26.38 29.68 33.41 39.11 47.21 50.44 47.06 AUG 0.17 0.46 0.29 0.20 0.24 28.07
SEP 22.87 20.85 36.39 28.53 33.98 37.72 43.51 51.65 53.20 50.34 SEP 0.14 0.31 0.25 0.25 1.92 25.71
OCT 0.11 0.11 0.12 0.14 0.42 1.39 2.97 OCT 0.08 0.10 0.10 0.09 0.10 0.07
NOV 0.30 5.16 10.51 18.56 22.69 26.73 29.80 39.88 43.10 47.59 NOV 0.17 0.34 0.27 0.13 0.20 0.30
DEC 1.80 7.12 11.34 19.37 22.03 37.52 39.75 45.27 51.83 46.05 DEC 0.18 0.21 0.23 0.23 0.28 16.25
mean 4.13 5.63 8.75 13.22 15.82 19.59 23.65 34.87 40.38 39.43 mean 0.13 0.21 0.19 0.13 0.30 7.46
std dev 7.17 6.71 10.90 10.62 12.07 14.13 15.17 12.61 10.17 11.30 std dev 0.03 0.12 0.07 0.06 0.51 10.40
median 0.2 3.5 5.6 13.7 15.8 20.2 25.6 39.3 41.7 46.0 median 0.1 0.1 0.2 0.1 0.1 1.3
max 22.87 20.85 36.39 28.53 33.98 37.72 43.51 51.65 53.20 50.34 max 0.18 0.46 0.29 0.25 1.92 28.07
min 0.09 0.09 0.09 0.10 0.10 0.22 2.28 11.12 24.06 12.28 min 0.08 0.10 0.10 0.08 0.09 0.07
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 0.10 0.17 0.16 0.32 0.13 0.13 0.33 0.13 JAN 0.15 0.10 0.12 0.09 0.12 0.07 JAN 0.12 0.09 0.09 0.10 0.24
FEB 0.09 0.13 0.13 0.17 0.33 0.12 0.11 0.15 0.12 FEB 0.12 0.08 0.11 0.07 0.10 0.10 FEB 0.10 0.08 0.09 0.12
MAR 0.08 0.13 0.13 0.34 0.52 0.12 0.12 0.28 0.12 MAR 0.13 0.09 0.12 0.08 0.10 0.12 MAR 0.11 0.08 0.08 0.10 0.20
APR 0.09 0.17 0.16 0.50 0.45 0.21 0.18 0.82 0.29 APR 0.11 0.07 0.09 0.06 0.10 0.12 APR 0.14 0.08 0.07 0.12 0.63
MAY 0.14 0.20 0.23 0.52 1.42 0.21 0.31 0.89 0.40 MAY 0.13 0.09 0.17 0.10 0.11 0.11 MAY 0.24 0.10 0.07 0.16 5.95
JUN 0.14 0.20 0.19 0.74 1.83 0.20 0.15 0.44 0.25 JUN 0.11 0.07 0.09 0.08 0.08 0.16 JUN 0.27 0.09 0.08 0.18 11.86
JUL 0.14 0.27 0.23 1.33 10.70 0.19 0.18 1.15 0.23 JUL 0.10 0.09 0.15 0.14 0.11 0.11 JUL 0.28 0.07 0.08 0.16 12.88
AUG 0.18 0.30 0.34 1.06 3.78 0.18 0.71 0.18 AUG 0.13 0.10 0.18 0.42 0.17 0.21 AUG 0.32 0.13 0.07 0.17 20.27
SEP 0.15 0.34 0.32 1.04 7.59 0.17 0.15 0.89 0.15 SEP 0.36 0.11 0.10 0.25 SEP 0.19 0.11 0.07 0.17 11.18
OCT 0.09 0.21 0.20 0.57 0.59 0.16 0.16 0.99 0.16 OCT 0.10 0.07 0.11 0.07 0.15 0.17 OCT 0.12 0.08 0.10 0.10 0.53
NOV 0.08 0.23 0.25 0.63 0.55 0.14 0.15 0.87 0.33 NOV 0.17 0.11 0.19 0.09 0.15 0.19 NOV 0.14 0.10 0.08 0.14 10.96
DEC 0.09 0.19 0.19 0.73 1.75 0.13 0.13 0.34 0.23 DEC 0.14 0.10 0.18 0.10 0.13 0.22 DEC 0.21 0.11 0.07 0.15 8.01
mean 0.11 0.21 0.21 0.66 2.68 0.16 0.16 0.65 0.22 mean 0.13 0.11 0.13 0.12 0.13 0.14 mean 0.19 0.09 0.08 0.14 6.90
std dev 0.03 0.06 0.07 0.34 3.42 0.04 0.05 0.33 0.09 std dev 0.02 0.08 0.04 0.10 0.05 0.05 std dev 0.08 0.02 0.01 0.03 6.68
median 0.09 0.20 0.19 0.60 1.42 0.16 0.15 0.77 0.20 median 0.13 0.09 0.12 0.09 0.12 0.12 median 0.17 0.09 0.08 0.15 6.98
max 0.18 0.34 0.34 1.33 10.70 0.21 0.31 1.15 0.40 max 0.17 0.36 0.19 0.42 0.25 0.22 max 0.32 0.13 0.10 0.18 20.27
min 0.08 0.13 0.13 0.17 0.33 0.12 0.11 0.15 0.12 min 0.10 0.07 0.09 0.06 0.08 0.07 min 0.10 0.07 0.07 0.10 0.12
25
Table 2.4 pH during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 7.3 7.3 7.6 7.2 7.6 7.7 7.9 8.0 8.0 8.0 JAN 6.2 6.6 6.7 6.3 6.5 6.7
FEB 6.9 7.0 7.2 6.9 7.3 7.9 8.3 8.2 7.9 7.8 FEB 6.7 6.6 6.7 6.5 6.5 6.3
MAR 7.3 7.3 7.6 7.3 7.7 7.9 8.0 8.0 7.9 7.7 MAR 6.6 6.8 6.8 6.4 6.7 6.5
APR 6.8 6.9 6.9 7.0 7.7 7.4 8.0 7.9 8.0 7.9 APR 6.6 6.8 6.8 6.4 6.6 6.5
MAY 7.1 7.3 7.3 7.5 7.8 8.3 8.1 8.0 8.0 7.9 MAY 6.9 6.9 7.0 6.6 6.9 6.8
JUN 6.8 6.9 6.9 7.0 7.1 7.2 7.4 7.8 7.9 7.6 JUN 7.0 7.1 7.1 6.4 6.8 7.0
JUL 7.0 7.1 7.1 7.3 7.6 7.7 8.0 8.1 8.1 7.7 JUL 6.6 7.0 6.8 6.1 6.6 6.9
AUG 7.0 7.2 7.2 7.3 7.5 7.6 7.8 7.9 7.9 7.9 AUG 7.4 7.4 7.1 6.9 7.0 7.1
SEP 7.1 7.1 7.2 7.4 7.6 7.7 7.9 8.0 8.1 7.9 SEP 6.9 7.1 6.8 6.8 6.8 7.1
OCT 6.0 6.1 6.2 6.0 6.3 6.5 7.0 OCT 6.1 6.2 6.2 5.6 5.9 5.5
NOV 7.3 7.2 7.3 7.3 7.5 7.6 7.7 7.9 8.0 7.7 NOV 6.6 7.0 7.0 6.5 6.7 6.5
DEC 7.5 7.3 7.3 7.5 7.5 8.0 8.0 8.1 8.1 8.0 DEC 6.8 7.1 7.0 7.0 7.0 7.3
mean 7.0 7.1 7.2 7.1 7.4 7.6 7.8 8.0 8.0 7.8 mean 6.7 6.9 6.8 6.5 6.7 6.7
std dev 0.4 0.3 0.4 0.4 0.4 0.5 0.3 0.1 0.1 0.1 std dev 0.3 0.3 0.2 0.4 0.3 0.5
median 7.1 7.2 7.2 7.3 7.6 7.7 8.0 8.0 8.0 7.9 median 6.7 7.0 6.8 6.5 6.7 6.8
max 7.5 7.3 7.6 7.5 7.8 8.3 8.3 8.2 8.1 8.0 max 7.4 7.4 7.1 7.0 7.0 7.3
min 6.0 6.1 6.2 6.0 6.3 6.5 7.0 7.8 7.9 7.6 min 6.1 6.2 6.2 5.6 5.9 5.5
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 5.0 6.7 6.8 6.7 6.9 6.9 6.7 5.6 JAN 6.2 6.2 6.3 6.4 6.6 6.5 JAN 5.9 5.7 3.8 6.4 6.1
FEB 4.7 6.6 6.6 6.4 6.4 6.6 6.5 6.3 6.0 FEB 5.8 5.8 6.1 6.2 6.1 6.2 FEB 6.0 5.6 3.8 5.9
MAR 5.4 6.7 6.9 6.7 6.7 6.9 6.8 6.6 5.9 MAR 6.2 6.2 6.3 6.4 6.5 6.5 MAR 5.8 6.6 3.9 6.3 5.8
APR 5.7 6.9 6.9 6.8 7.0 7.4 7.1 7.4 7.0 APR 6.6 6.2 6.5 6.3 6.7 6.8 APR 6.5 6.2 4.0 6.6 7.0
MAY 7.2 7.4 7.3 7.1 7.2 7.7 7.5 7.6 7.3 MAY 7.1 6.8 7.0 6.2 7.0 7.1 MAY 6.9 6.6 4.0 6.7 7.2
JUN 6.5 6.8 6.5 6.6 7.0 7.6 7.0 7.5 7.2 JUN 6.6 6.1 6.5 6.3 6.8 6.9 JUN 6.9 6.4 4.0 6.8 6.9
JUL 6.4 7.1 6.9 6.6 8.0 8.1 7.2 7.8 6.9 JUL 6.6 6.7 6.8 6.2 6.8 6.7 JUL 6.9 4.8 3.9 7.1 7.0
AUG 6.6 6.5 6.2 6.6 7.2 7.2 7.6 6.9 AUG 6.8 6.5 6.6 6.0 7.0 7.2 AUG 7.1 6.8 3.9 6.8 7.0
SEP 6.4 6.8 6.4 6.5 7.8 7.3 6.8 7.6 6.7 SEP 6.3 6.7 6.2 7.0 7.0 SEP 6.8 6.3 4.1 6.9 7.2
OCT 4.4 6.6 6.5 6.6 6.9 7.2 7.0 7.5 6.3 OCT 5.9 5.1 5.9 5.9 6.4 6.6 OCT 5.7 5.6 3.8 6.3 6.4
NOV 5.5 6.9 6.8 6.9 6.9 7.3 7.2 7.4 6.6 NOV 6.6 6.6 6.5 6.4 7.0 6.9 NOV 6.2 6.1 4.0 6.8 6.6
DEC 5.3 6.7 6.9 6.9 6.8 7.1 7.0 6.9 6.6 DEC 6.9 6.7 6.6 6.1 6.9 7.0 DEC 6.6 6.3 4.0 6.9 6.9
mean 5.8 6.8 6.7 6.7 7.1 7.3 7.0 7.2 6.6 mean 6.5 6.3 6.5 6.2 6.7 6.8 mean 6.4 6.1 3.9 6.7 6.7
std dev 0.9 0.2 0.3 0.2 0.5 0.4 0.3 0.5 0.5 std dev 0.4 0.5 0.3 0.2 0.3 0.3 std dev 0.5 0.6 0.1 0.3 0.5
median 5.6 6.8 6.8 6.7 7.0 7.3 7.0 7.5 6.7 median 6.6 6.3 6.5 6.2 6.8 6.9 median 6.6 6.3 4.0 6.8 6.9
max 7.2 7.4 7.3 7.1 8.0 8.1 7.5 7.8 7.3 max 7.1 6.8 7.0 6.4 7.0 7.2 max 7.1 6.8 4.1 7.1 7.2
min 4.4 6.5 6.2 6.4 6.4 6.6 6.5 6.3 5.6 min 5.8 5.1 5.9 5.9 6.1 6.2 min 5.7 4.8 3.8 6.3 5.8
26
Table 2.5 Dissolved Oxygen (mg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 12.4 12.1 12.1 11.2 11.3 11.2 11.0 10.7 10.6 10.0 JAN 12.4 12.1 11.9 11.5 11.4 11.3
FEB 11.7 11.7 11.7 11.4 11.7 11.5 11.4 11.4 10.5 11.3 FEB 12.7 12.6 12.4 11.7 11.8 11.0
MAR 10.9 11.0 11.0 10.5 10.5 10.5 10.5 10.0 10.0 10.4 MAR 10.4 10.2 9.9 8.7 9.3 8.0
APR 7.2 7.1 7.0 7.0 6.9 7.3 7.9 7.9 8.2 7.7 APR 9.0 8.7 8.4 6.2 7.4 6.4
MAY 5.6 7.3 6.0 6.4 7.5 10.9 9.6 7.6 7.4 7.0 MAY 8.0 7.8 6.6 4.9 5.8 6.3
JUN 6.2 6.4 6.4 6.0 6.4 6.4 6.8 6.8 7.1 5.8 JUN 7.5 7.3 6.9 5.3 6.1 5.8
JUL 4.6 4.8 4.7 5.2 6.3 6.1 8.0 7.4 7.0 5.9 JUL 6.7 6.0 3.8 3.9 3.9 5.3
AUG 3.2 3.4 4.2 4.2 4.7 5.2 5.5 5.9 5.8 5.9 AUG 8.4 7.3 5.6 4.7 5.0 4.0
SEP 3.8 4.1 4.1 4.8 5.0 6.0 5.8 6.1 6.0 5.4 SEP 7.4 6.1 3.9 4.1 3.7 3.8
OCT 4.8 5.0 4.8 3.9 4.0 4.2 5.0 OCT 7.4 6.4 5.8 4.3 4.5 3.8
NOV 8.1 8.1 7.7 8.0 7.3 7.3 7.5 7.7 8.1 7.7 NOV 9.7 9.2 8.3 7.8 8.0 7.2
DEC 10.1 9.8 9.9 9.6 10.3 9.6 9.5 9.6 9.1 9.5 DEC 10.3 10.0 9.3 9.4 8.9 8.6
mean 7.4 7.6 7.5 7.4 7.7 8.0 8.2 8.3 8.2 7.9 mean 9.2 8.6 7.7 6.9 7.2 6.8
std dev 3.2 3.0 3.0 2.7 2.7 2.6 2.2 1.9 1.7 2.1 std dev 2.0 2.2 2.8 2.9 2.8 2.6
median 6.7 7.2 6.7 6.7 7.1 7.3 8.0 7.7 8.1 7.7 median 8.7 8.3 7.6 5.8 6.8 6.4
max 12.4 12.1 12.1 11.4 11.7 11.5 11.4 11.4 10.6 11.3 max 12.7 12.6 12.4 11.7 11.8 11.3
min 3.2 3.4 4.1 3.9 4.0 4.2 5.0 5.9 5.8 5.4 min 6.7 6.0 3.8 3.9 3.7 3.8
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 10.9 13.0 13.7 11.2 13.0 12.9 12.0 11.9 JAN 13.5 14.1 16.8 14.9 17.0 17.5 JAN 10.6 10.4 9.0 8.7 11.3
FEB 11.1 12.1 12.1 11.9 10.8 12.7 11.8 10.6 10.2 FEB 11.9 12.0 11.3 11.3 11.6 12.0 FEB 10.7 10.9 11.1 9.6
MAR 11.3 8.9 10.5 9.3 9.7 11.4 9.7 10.4 8.9 MAR 11.4 11.8 10.6 10.2 11.8 12.1 MAR 11.0 11.3 10.5 10.8 11.1
APR 5.7 7.2 8.6 7.0 7.5 10.3 8.0 3.2 0.6 APR 9.1 6.6 5.5 4.3 9.0 8.0 APR 7.2 6.6 5.6 4.6 8.4
MAY 1.9 6.7 3.1 3.1 6.7 7.5 5.5 3.0 0.2 MAY 7.0 6.9 5.9 1.5 7.4 4.4 MAY 5.6 5.3 5.5 2.3 6.4
JUN 0.7 5.4 1.8 1.4 6.5 8.0 5.7 5.1 3.5 JUN 6.5 6.3 5.0 2.6 7.5 5.4 JUN 5.0 4.6 5.3 2.1 4.4
JUL 0.3 6.1 3.1 0.8 9.1 10.4 4.8 4.1 0.5 JUL 6.4 6.5 5.4 4.8 7.1 6.3 JUL 5.3 4.7 3.8 3.7 5.0
AUG 0.5 5.8 1.3 4.9 8.5 7.0 6.5 1.7 AUG 7.2 7.4 6.3 0.5 7.7 4.7 AUG 5.4 5.2 5.2 2.9 4.6
SEP 2.1 4.9 0.5 1.0 10.1 7.5 5.5 4.7 0.7 SEP 7.2 5.3 0.3 8.0 2.9 SEP 3.7 4.8 5.0 2.6 5.4
OCT 5.2 7.4 3.6 6.6 8.4 9.5 7.7 6.2 0.4 OCT 5.4 5.9 5.6 3.5 8.3 7.2 OCT 2.9 5.7 4.7 5.5 4.6
NOV 7.2 9.4 5.1 7.3 7.1 11.2 9.7 6.3 1.0 NOV 9.0 9.0 5.2 3.0 9.6 5.5 NOV 5.8 6.8 6.7 6.1 5.7
DEC 8.9 9.7 9.6 9.2 10.6 12.4 11.0 8.8 6.2 DEC 10.6 10.2 8.3 4.6 10.7 8.7 DEC 7.1 7.6 8.0 5.4 7.4
mean 5.5 8.1 6.1 6.1 8.6 10.4 8.3 6.7 3.8 mean 8.9 8.7 7.6 5.1 9.6 7.9 mean 6.7 7.0 6.7 5.0 7.0
std dev 4.4 2.6 4.6 3.9 1.6 2.0 2.7 3.0 4.3 std dev 2.6 2.7 3.6 4.6 2.8 4.2 std dev 2.7 2.5 2.4 2.8 2.5
median 5.5 7.3 4.4 6.8 8.5 10.4 7.9 6.3 1.4 median 9.0 7.3 5.8 3.9 8.7 6.8 median 5.7 6.2 5.6 4.6 6.1
max 11.3 13.0 13.7 11.9 10.8 13.0 12.9 12.0 11.9 max 13.5 14.1 16.8 14.9 17.0 17.5 max 11.0 11.3 11.1 10.8 11.3
min 0.3 4.9 0.5 0.8 6.5 7.5 4.8 3.0 0.2 min 5.4 5.9 5.0 0.3 7.1 2.9 min 2.9 4.6 3.8 2.1 4.4
27
0
1
2
3
4
5
6
7
8
9
10
NC11 AC DP IC NAV HB BRR M61 M54 M42 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,
1995-2009 versus 2010.
1995-2009
2010
28
Table 2.6 Field Turbidity (NTU) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 12 12 12 20 14 13 9 8 10 6 JAN 29 39 34 10 19 7
FEB 30 31 32 26 36 64 42 30 16 25 FEB 37 43 41 16 25 6
MAR 13 15 15 15 19 20 16 11 14 6 MAR 34 42 43 4 16 5
APR 16 14 18 13 14 9 8 7 6 11 APR 23 28 26 8 15 4
MAY 18 21 11 11 15 13 15 6 8 15 MAY 11 13 14 7 7 18
JUN 11 11 12 11 11 11 9 9 7 17 JUN 22 20 17 8 11 14
JUL 13 11 9 7 7 8 9 6 6 14 JUL 17 12 19 9 13 11
AUG 14 11 10 9 9 10 14 5 11 4 AUG 8 9 13 5 10 20
SEP 19 24 12 7 16 7 4 4 5 13 SEP 8 10 15 11 22 19
OCT 30 38 50 25 45 34 20 OCT 41 31 24 7 16 7
NOV 17 11 9 10 9 7 6 6 7 10 NOV 8 8 12 5 9 20
DEC 9 9 6 7 7 12 12 11 6 9 DEC 9 7 5 5 11 12
mean 17 17 16 13 17 17 14 9 9 12 mean 21 22 22 8 15 12
std dev 7 9 13 7 12 16 10 7 4 6 std dev 12 14 12 3 5 6
median 15 13 12 11 14 12 11 7 7 11 median 20 17 18 8 14 12
max 30 38 50 26 45 64 42 30 16 25 max 41 43 43 16 25 20
min 9 9 6 7 7 7 4 4 5 4 min 8 7 5 4 7 4
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 9 2 0 1 5 7 13 9 JAN 4 2 1 0 6 8 JAN 6 3 3 5 25
FEB 10 3 2 7 36 9 10 32 20 FEB 6 4 1 2 10 13 FEB 33 5 2 15
MAR 8 6 4 2 9 5 6 10 12 MAR 7 2 1 1 6 10 MAR 5 3 2 12 19
APR 14 7 3 5 9 10 6 7 18 APR 4 2 2 1 6 7 APR 3 2 3 3 6
MAY 2 3 8 3 7 22 3 7 27 MAY 4 4 3 4 8 5 MAY 6 7 3 7 9
JUN 5 5 6 4 9 12 86 25 49 JUN 6 5 4 3 122 38 JUN 6 4 2 5 25
JUL 3 2 14 7 12 2 7 20 30 JUL 14 3 5 30 30 45 JUL 5 3 1 5 10
AUG 4 9 9 6 8 5 22 12 AUG 14 9 13 56 3 4 AUG 2 2 1 5 13
SEP 6 2 23 13 3 3 4 9 8 SEP 4 7 17 3 6 SEP 2 2 1 3 6
OCT 5 3 2 3 5 6 6 13 15 OCT 3 2 2 2 10 5 OCT 3 2 1 8 4
NOV 5 3 4 2 16 5 5 8 8 NOV 6 4 14 4 3 3 NOV 4 2 2 3 20
DEC 8 5 2 3 12 8 12 17 21 DEC 3 3 3 2 4 5 DEC 3 9 2 3 22
mean 7 4 6 5 11 8 13 15 19 mean 6 4 5 10 18 12 mean 7 4 2 5 15
std dev 3 2 7 3 9 6 23 8 12 std dev 4 2 4 17 34 14 std dev 8 2 1 3 8
median 6 3 4 4 9 6 6 13 17 median 6 4 3 3 6 7 median 5 3 2 5 14
max 14 9 23 13 36 22 86 32 49 max 14 9 14 56 122 45 max 33 9 3 12 25
min 2 2 0 1 3 2 3 7 8 min 3 2 1 0 3 3 min 2 2 1 3 4
29
0
5
10
15
20
25
30
NC11 AC DP IC NAV HB BRR M61 M54 M42 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,
1995-2009 versus 2010.
1995-2009
2010
30
Table 2.7 Total Suspended Solids (mg/L) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 6 6 6 11 10 11 8 7 8 10 JAN 15 21 21 7 5
FEB 12 16 12 10 14 57 24 17 18 18 FEB 18 19 21 12 2
MAR 7 8 7 9 13 17 12 9 8 8 MAR 33 55 52 13 9
APR 15 10 10 9 14 8 8 12 8 16 APR 23 25 28 16 8
MAY 14 20 10 9 16 15 9 14 9 27 MAY 9 9 12 3 6
JUN 6 7 6 9 9 8 7 8 12 17 JUN 18 19 10 7 14
JUL 8 6 8 8 12 12 12 10 10 18 JUL 9 9 2 10 9
AUG 12 11 11 12 14 10 18 8 9 14 AUG 9 12 14 10 38
SEP 31 37 20 13 25 19 13 16 12 34 SEP 4 8 7 15 28
OCT 22 25 30 16 54 24 16 OCT 17 20 13 12 6
NOV 13 9 8 11 11 13 7 12 8 12 NOV 3 5 6 6 21
DEC 9 7 8 8 11 22 17 18 16 16 DEC 6 6 4 9 13
mean 13 14 11 10 17 18 13 12 11 17 mean 14 17 16 10 13
std dev 7 10 7 2 12 13 5 4 4 8 std dev 9 14 14 4 11
median 12 10 9 10 13 14 12 12 9 16 median 12 15 13 10 9
max 31 37 30 16 54 57 24 18 18 34 max 33 55 52 16 38
min 6 6 6 8 9 8 7 7 8 8 min 3 5 2 3 2
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1 1 1 1 1 3 6 4 JAN 1 1 1 1 3 1 JAN 3 1 1 2
FEB 2 1 1 2 9 36 7 18 7 FEB 2 1 1 1 9 4 FEB 3 1 1
MAR 7 4 1 1 4 3 4 5 5 MAR 2 1 1 1 4 3 MAR 2 1 1 4
APR 5 5 1 2 5 4 1 3 10 APR 5 1 1 3 9 4 APR 5 2 1 5
MAY 5 3 10 4 8 30 2 6 25 MAY 2 2 2 10 6 3 MAY 5 2 2 4
JUN 6 6 9 4 7 14 37 14 24 JUN 6 4 4 3 105 23 JUN 8 1 2 3
JUL 5 5 10 6 29 2 2 12 4 JUL 10 2 5 13 26 30 JUL 4 2 2 4
AUG 5 10 8 4 7 3 12 8 AUG 15 7 13 22 4 4 AUG 5 2 2 5
SEP 7 2 13 8 6 2 4 8 11 SEP 2 4 11 2 5 SEP 4 2 2 4
OCT 2 2 2 2 4 3 2 9 118 OCT 2 2 2 3 10 8 OCT 2 2 2 3
NOV 2 2 2 2 34 10 2 3 15 NOV 4 3 9 6 2 3 NOV 3 2 2 2
DEC 2 2 3 3 6 4 8 8 9 DEC 2 2 2 2 2 3 DEC 5 2 2 2
mean 4 4 5 3 11 10 6 9 20 mean 5 2 4 6 15 8 mean 4 2 2 4
std dev 2 3 5 2 11 12 10 5 32 std dev 4 2 4 7 29 9 std dev 2 0 0 1
median 5 2 2 3 7 4 3 8 9 median 2 2 2 3 5 4 median 4 2 2 4
max 7 10 13 8 34 36 37 18 118 max 15 7 13 22 105 30 max 8 2 2 5
min 1 1 1 1 4 1 1 3 4 min 1 1 1 1 2 1 min 2 1 1 2
31
Table 2.8 Light Attenuation (k) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 2.62 3.11 2.44 3.43 2.94 2.97 2.56 2.08 2.78 2.11 JAN 3.41 3.50 3.25 2.94 3.08 4.41
FEB 3.51 3.51 3.47 4.06 4.00 6.20 4.48 3.75 2.38 3.38 FEB 3.21 3.62 3.37 2.80 3.22 3.62
MAR 2.51 2.62 2.63 3.05 3.02 3.14 2.92 2.14 2.20 1.63 MAR 3.9 4.29 4.08 2.98 3.26 4.07
APR 3.35 3.11 3.19 3.07 3.07 2.54 2.24 1.84 1.46 2.24 APR 3.2 3.50 3.68 3.25 3.37 4.16
MAY 2.30 MAY 2.4 2.46 2.58 2.93 2.47 5.12
JUN 2.14 2.45 2.43 2.41 2.46 2.39 1.50 1.68 1.98 2.20 JUN
JUL 2.81 2.65 2.39 1.48 1.78 1.94 1.91 1.38 1.17 1.69 JUL 3.7 3.75 4.80 4.44 4.26 2.99
AUG 2.30 2.08 2.13 1.77 1.82 1.74 1.75 1.06 0.87 1.03 AUG 2.38 3.62 3.37 3.09 3.38
SEP 3.34 3.58 2.34 1.69 3.06 1.56 1.13 0.98 1.01 2.03 SEP 1.97 2.38 3.39 3.02 3.70 2.47
OCT 5.75 5.87 7.39 6.12 5.24 OCT 4.48 4.00 3.74 4.14 4.24 4.59
NOV NOV
DEC 3.31 2.87 2.90 3.10 2.06 2.30 1.62 1.62 0.87 1.65 DEC 1.96 2.03 2.78 2.73 3.32 3.80
mean 2.88 2.89 2.97 2.99 3.16 3.09 2.54 1.84 1.64 2.03 mean 3.06 3.32 3.50 3.23 3.44 3.86
std dev 0.51 0.49 1.06 1.31 1.64 1.69 1.34 0.82 0.72 0.61 std dev 0.85 0.75 0.63 0.58 0.56 0.78
median 2.81 2.87 2.54 3.06 2.98 2.47 2.08 1.68 1.46 2.07 median 3.20 3.56 3.38 3.00 3.32 3.94
max 3.51 3.58 5.75 5.87 7.39 6.20 5.24 3.75 2.78 3.38 max 4.48 4.29 4.80 4.44 4.26 5.12
min 2.14 2.08 2.13 1.48 1.78 1.56 1.13 0.98 0.87 1.03 min 1.96 2.03 2.58 2.73 2.47 2.47
32
Table 2.9 Total Nitrogen (µg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 1,060 1,090 1,060 1,100 1,090 990 690 660 560 480 JAN 600 960 610 850 1,430
FEB 1,240 1,140 1,150 1,430 1,430 1,500 1,220 940 380 890 FEB 1,010 1,020 1,030 1,020 1,540
MAR 1,200 1,270 1,280 1,290 1,290 1,040 1,030 630 590 450 MAR 1,410 1,400 1,420 1,180 1,480
APR 1,170 990 1,060 960 1,240 810 560 420 270 540 APR 1,160 1,260 1,110 2,340 1,230
MAY 1,170 1,030 850 750 680 730 450 200 600 400 MAY 1,440 1,470 1,750 1,390 980
JUN 1,040 1,140 1,150 1,660 1,120 1,120 1,080 700 510 540 JUN 1,140 1,090 1,090 1,250 940
JUL 1,200 1,070 830 1,040 1,050 490 430 200 200 300 JUL 1,390 1,260 1,210 1,200 790
AUG 1,250 1,350 1,310 1,030 950 960 770 650 620 550 AUG 360 880 690 630 730
SEP 830 890 690 360 580 510 340 130 120 250 SEP 620 850 870 960 420
OCT 990 900 930 930 830 810 870 OCT 1,070 920 930 810 910
NOV 1,240 970 870 760 760 590 660 150 420 140 NOV 1,340 1,360 1,170 980 1,060
DEC 1,480 1,300 1,270 770 850 670 580 410 300 480 DEC 2,180 2,110 1,520 1,530 990
mean 1,156 1,095 1,038 1,007 989 852 723 463 415 456 mean 1,143 1,215 1,117 1,178 1,042
std dev 155 145 194 330 248 278 266 259 167 186 std dev 460 339 318 426 317
median 1,185 1,080 1,060 995 1,000 810 675 420 420 480 median 1,150 1,175 1,100 1,100 985
max 1,480 1,350 1,310 1,660 1,430 1,500 1,220 940 620 890 max 2,180 2,110 1,750 2,340 1,540
min 830 890 690 360 580 490 340 130 120 140 min 360 850 610 630 420
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1,430 2,950 2,160 3,820 1,840 2,230 4,420 850 JAN 2,400 2,080 1,340 190 1,300 1,860 JAN 1,720 1,380 640 580
FEB 1,810 2,990 2,820 3,570 4,350 2,330 2,660 2,070 1,370 FEB 3,090 2,250 2,460 780 1,560 2,080 FEB 1,540 700 1,420
MAR 960 2,220 1,910 3,570 2,550 1,500 1,920 4,140 640 MAR 2,550 2,090 2,010 740 1,250 1,270 MAR 1,590 1,420 600 810
APR 1,500 1,640 830 1,700 1,430 1,180 3,470 19,500 940 APR 1,490 840 740 890 840 830 APR 1,350 920 900 910
MAY 1,000 1,820 1,200 1,020 1,190 1,910 3,780 21,100 2,800 MAY 1,530 1,320 1,160 1,150 950 760 MAY 1,230 1,250 1,100 1,730
JUN 1,100 1,340 530 820 1,070 1,080 3,420 6,760 2,510 JUN 1,350 1,150 900 880 1,360 840 JUN 1,110 1,120 1,310 1,830
JUL 1,100 730 1,200 1,100 2,060 11,300 2,710 30,000 980 JUL 1,350 860 940 800 670 910 JUL 890 1,100 1,200 830
AUG 2,500 1,310 1,100 840 1,460 2,290 13,200 820 AUG 1,480 670 830 1,440 250 160 AUG 450 1,250 1,040 1,540
SEP 1,090 1,810 1,060 750 3,490 910 2,410 19,000 1,220 SEP 870 2,650 1,250 450 120 SEP 890 920 940 1,220
OCT 1,490 880 630 970 1,100 740 2,650 26,800 1,110 OCT 880 800 570 720 910 890 OCT 810 730 850 670
NOV 900 1,000 500 880 860 350 800 21,800 580 NOV 1,250 710 1,040 570 460 300 NOV 1,060 830 1,000 670
DEC 1,200 1,330 500 1,670 840 630 940 3,800 1,020 DEC 1,520 670 680 330 170 200 DEC 680 610 500 1,120
mean 1,340 1,668 1,203 1,726 1,855 2,161 2,440 14,383 1,237 mean 1,717 1,193 1,277 812 848 852 mean 1,110 1,019 958 1,083
std dev 435 709 705 1,152 1,104 2,946 878 9,456 671 std dev 634 577 677 342 438 609 std dev 373 262 271 423
median 1,150 1,490 1,080 1,060 1,430 1,180 2,530 16,100 1,000 median 1,490 865 990 790 875 835 median 1,085 1,010 970 910
max 2,500 2,990 2,820 3,820 4,350 11,300 3,780 30,000 2,800 max 3,090 2,250 2,650 1,440 1,560 2,080 max 1,720 1,420 1,420 1,830
min 900 730 500 750 840 350 800 2,070 580 min 880 670 570 190 170 120 min 450 610 500 580
33
0
200
400
600
800
1,000
1,200
1,400
1,600
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210
To
t
a
l
N
i
t
r
o
g
e
n
(
µg/
L
)
Figure 2.4 Total Nitrogen at the Lower Cape Fear River Program mainstem stations,
1995-2009 versus 2010.
1995-2009
2010
34
Table 2.10 Nitrate/Nitrite (µg/l) during 2010 at the Lower Cape Fear River stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 760 790 760 700 690 590 490 360 260 180 JAN 600 560 610 650 930
FEB 640 640 650 830 730 700 620 540 180 490 FEB 510 520 530 620 940
MAR 700 670 680 690 690 640 630 430 390 250 MAR 810 800 720 580 580
APR 370 390 360 360 340 310 260 220 70 140 APR 560 560 510 440 330
MAY 670 530 450 350 280 130 50 10 10 10 MAY 840 970 850 690 380
JUN 540 540 550 960 520 520 480 300 210 40 JUN 640 590 690 650 440
JUL 500 470 430 340 250 190 30 10 10 10 JUL 590 460 510 400 290
AUG 550 550 510 430 350 260 170 50 20 50 AUG 360 580 690 630 330
SEP 430 390 390 360 280 210 140 30 10 50 SEP 620 550 470 560 420
OCT 390 400 530 330 330 310 270 OCT 470 420 430 310 210
NOV 740 570 470 360 360 290 260 150 120 40 NOV 1,040 860 670 480 160
DEC 980 900 770 470 450 270 180 110 10 80 DEC 1,880 1,710 1,120 1,030 390
mean 606 570 546 515 439 368 298 201 117 122 mean 743 715 650 587 450
std dev 170 152 133 211 168 183 199 175 122 137 std dev 384 339 184 174 240
median 595 545 520 395 355 300 260 150 70 50 median 610 570 640 600 385
max 980 900 770 960 730 700 630 540 390 490 max 1,880 1,710 1,120 1,030 940
min 370 390 360 330 250 130 30 10 10 10 min 360 420 430 310 160
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 330 2,550 1,960 3,520 1,540 1,930 4,420 650 JAN 2,000 168 134 190 1,100 1,360 JAN 1,020 980 40 280
FEB 610 2,290 2,020 3,070 3,350 1,630 1,860 1,170 570 FEB 2,390 1,750 1,860 480 960 1,080 FEB 840 10 820
MAR 60 1,620 1,410 3,070 1,850 1,000 1,320 3,840 140 MAR 2,150 1,690 1,510 340 750 770 MAR 890 920 10 310
APR 100 340 30 900 330 180 2,170 19,500 40 APR 790 240 40 90 240 230 APR 450 220 10 110
MAY 10 520 10 220 90 510 2,880 21,100 10 MAY 930 520 60 450 250 160 MAY 230 350 10 630
JUN 10 140 30 120 170 280 1,820 5,460 810 JUN 550 250 100 80 260 140 JUN 310 320 110 830
JUL 10 30 10 10 60 10,700 1,710 30,000 80 JUL 850 460 440 10 170 310 JUL 190 100 10 230
AUG 10 110 10 40 360 1,390 12,000 120 AUG 880 370 130 40 250 60 AUG 150 150 40 740
SEP 90 610 60 50 1,390 210 1,410 19,000 20 SEP 470 1,950 50 450 10 SEP 290 220 40 520
OCT 90 280 30 470 600 240 1,850 26,800 110 OCT 380 200 70 20 210 290 OCT 110 130 50 170
NOV 10 300 10 680 160 50 300 21,800 80 NOV 650 210 40 70 260 10 NOV 160 230 10 70
DEC 200 630 10 1,270 140 130 340 3,000 420 DEC 1,120 370 380 30 170 10 DEC 180 310 10 220mean1287854661,118 773 1,497 1,582 14,008 254 mean 1,154 558 560 154 423 369 mean 402 328 97 374
std dev 172 833 781 1,272 986 2,960 689 9,763 269 std dev 661 531 718 164 313 434 std dev 312 293 220 250
median 75 430 30 575 330 280 1,765 15,500 115 median 880 370 132 75 255 195 median 260 225 25 280
max 610 2,550 2,020 3,520 3,350 10,700 2,880 30,000 810 max 2,390 1,750 1,950 480 1,100 1,360 max 1,020 980 820 830
min 10 30 10 10 60 50 300 1,170 10 min 380 168 40 10 170 10 min 110 10 10 70
35
Table 2.11 Ammonium (µg/l) during 2010 at the Lower Cape Fear River stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 5 80 80 100 90 90 70 50 10 20 JAN 50 60 60 60 40
FEB 5 5 10 20 30 20 40 20 5 20 FEB 10 10 5 10 10
MAR 30 10 20 70 150 80 50 30 30 10 MAR 40 80 70 40 40
APR 40 50 60 80 240 70 60 30 5 5 APR 20 60 60 50 40
MAY 90 70 80 60 160 5 5 5 5 5 MAY 20 20 120 120 20
JUN 60 60 60 80 60 70 90 30 20 40 JUN 40 80 70 70 60
JUL 70 70 60 30 5 10 10 5 5 5 JUL 40 180 160 90 10
AUG 30 40 10 10 10 5 10 5 5 5 AUG 30 220 50 50 300
SEP 20 20 5 10 5 5 5 5 5 5 SEP 20 210 70 20 60
OCT 40 30 70 20 60 50 50 OCT 30 40 50 20 10
NOV 50 50 50 80 80 70 80 20 20 5 NOV 40 60 90 60 5
DEC 90 80 90 100 120 60 50 30 20 10 DEC 30 40 40 30 70
mean 44 47 50 55 84 45 43 21 12 12 mean 31 88 70 52 55
std dev 29 26 30 35 73 33 30 15 9 11 std dev 12 73 39 32 80
median 40 50 60 65 70 55 50 20 5 5 median 30 60 65 50 40
max 90 80 90 100 240 90 90 50 30 40 max 50 220 160 120 300min55510555555min10105105
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 130 110 30 50 90 110 130 50 JAN 120 20 10 20 50 260 JAN 100 5 10 40
FEB 150 70 40 20 40 30 50 210 40 FEB 60 20 40 10 20 190 FEB 20 5 10
MAR 40 30 30 20 100 5 30 40 30 MAR 60 30 30 40 60 70 MAR 30 10 30 220
APR 180 110 20 130 150 110 40 100 190 APR 40 30 20 40 20 40 APR 70 20 5 160
MAY 40 620 80 100 230 480 60 150 930 MAY 40 40 70 40 50 60 MAY 60 70 50 410
JUN 80 80 30 140 80 100 380 420 710 JUN 120 70 50 60 70 160 JUN 10 30 80 500
JUL 10 30 100 340 60 10 40 60 150 JUL 50 40 50 280 40 40 JUL 20 30 40 140
AUG 70 90 50 160 140 90 110 120 AUG 70 50 100 500 40 50 AUG 10 50 160 290
SEP 160 350 90 260 680 180 150 120 200 SEP 30 50 90 20 30 SEP 40 30 100 280
OCT 250 100 20 30 60 60 50 30 60 OCT 10 5 5 10 30 30 OCT 30 5 10 90
NOV 10 150 20 50 230 40 40 60 10 NOV 30 5 40 5 10 5 NOV 10 10 5 100
DEC 70 70 50 60 140 70 70 50 170 DEC 5 10 50 20 20 5 DEC 40 30 10 720
mean 99 151 47 113 174 107 93 123 222 mean 55 29 43 93 36 78 mean 37 25 43 268
std dev 75 170 28 101 180 134 97 107 291 std dev 38 19 26 148 19 81 std dev 28 20 48 205
median 75 95 35 80 140 70 55 105 135 median 50 30 45 40 35 45 median 30 25 20 220
max 250 620 100 340 680 480 380 420 930 max 120 70 100 500 70 260 max 100 70 160 720
min 10 30 20 20 40 5 30 30 10 min 5 5 5 5 10 5 min 10 5 5 40
36
Table 2.12 Total Kjeldahl Nitrogen (µg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 300 300 300 400 400 400 200 300 300 300 JAN 100 400 100 200 500
FEB 600 500 500 600 700 800 600 400 200 400 FEB 500 500 500 400 600
MAR 500 600 600 600 600 400 400 200 200 200 MAR 600 600 700 600 900
APR 800 600 700 600 900 500 300 200 200 400 APR 600 700 600 1,900 900
MAY 500 500 400 400 400 600 400 200 600 400 MAY 600 500 900 700 600
JUN 500 600 600 700 600 600 600 400 300 500 JUN 500 500 400 600 500
JUL 700 600 400 700 800 300 400 200 200 300 JUL 800 800 700 800 500
AUG 700 800 800 600 600 700 600 600 600 500 AUG 100 300 100 100 400
SEP 400 500 300 100 300 300 200 100 100 200 SEP 100 300 400 400 100
OCT 600 500 400 600 500 500 600 OCT 600 500 500 500 700
NOV 500 400 400 400 400 300 400 100 300 100 NOV 300 500 500 500 900
DEC 500 400 500 300 400 400 400 300 300 400 DEC 300 400 400 500 600
mean 550 525 492 500 550 483 425 273 300 336 mean 425 500 483 600 600
std dev 132 123 150 173 176 157 142 142 154 123 std dev 228 141 223 434 224
median 500 500 450 600 550 450 400 200 300 400 median 500 500 500 500 600
max 800 800 800 700 900 800 600 600 600 500 max 800 800 900 1,900 900
min 300 300 300 100 300 300 200 100 100 100 min 100 300 100 100 100
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1,100 400 200 300 300 300 100 200 JAN 400 400 100 100 200 500 JAN 700 400 600 300
FEB 1,200 700 800 500 1,000 700 800 900 800 FEB 700 500 600 300 600 1,000 FEB 700 700 600 300
MAR 900 600 500 500 700 500 600 300 500 MAR 400 400 500 400 500 500 MAR 700 500 600 500
APR 1,400 1,300 800 800 1,100 1,000 1,300 100 900 APR 700 600 700 800 600 600 APR 900 700 900 800
MAY 1,000 1,300 1,200 800 1,100 1,400 900 100 2,800 MAY 600 800 1,100 700 700 600 MAY 1,000 900 1,100 1,100
JUN 1,100 1,200 500 700 900 800 1,600 1,300 1,700 JUN 800 900 800 800 1,100 700 JUN 800 800 1,200 1,000
JUL 1,100 700 1,200 1,100 2,000 600 1,000 100 900 JUL 500 400 500 800 500 600 JUL 700 1,000 1,200 600
AUG 2,500 1,200 1,100 800 1,100 900 1,200 700 AUG 600 300 700 1,400 100 100 AUG 300 1,100 1,000 800
SEP 1,000 1,200 1,000 700 2,100 700 1,000 100 1,200 SEP 400 700 1,200 100 100 SEP 600 700 900 700
OCT 1,400 600 600 500 500 500 800 100 1,000 OCT 500 600 500 700 700 600 OCT 700 600 800 500
NOV 900 700 500 200 700 300 500 100 500 NOV 600 500 1,000 500 200 300 NOV 900 600 1,000 600
DEC 1,000 700 500 400 700 500 600 800 600 DEC 400 300 300 300 100 200 DEC 500 300 500 900
mean 1,217 883 742 608 1,082 664 858 433 983 mean 564 508 625 667 450 483 mean 708 692 867 675
std dev 418 313 312 243 495 305 338 455 659 std dev 130 180 265 361 301 254 std dev 180 225 236 245
median 1,100 700 700 600 1,000 600 850 100 850 median 600 450 650 700 500 550 median 700 700 900 650
max 2,500 1,300 1,200 1,100 2,100 1,400 1,600 1,300 2,800 max 800 900 1,100 1,400 1,100 1,000 max 1,000 1,100 1,200 1,100
min 900 400 200 200 500 300 300 100 200 min 400 300 100 100 100 100 min 300 300 500 300
37
Table 2.13 Total Phosphorus (µg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 90 80 150 70 130 60 60 50 60 50 JAN 120 200 90 130 60
FEB 80 60 70 70 70 140 80 60 40 50 FEB 80 90 80 60 40
MAR 80 80 70 70 110 80 80 40 50 30 MAR 150 150 170 90 100
APR 150 100 90 80 100 70 50 40 30 40 APR 120 140 140 100 70
MAY 110 110 90 80 110 110 40 30 20 50 MAY 140 140 160 140 90
JUN 210 110 190 70 130 70 90 40 30 20 JUN 140 160 130 130 90
JUL 140 130 110 100 80 80 70 40 30 40 JUL 150 180 170 140 90
AUG 150 130 130 120 100 90 70 40 40 40 AUG 120 200 200 170 160
SEP 150 160 140 110 110 90 90 60 100 60 SEP 140 190 160 210 130
OCT 120 140 180 150 180 130 100 OCT 130 120 110 100 150
NOV 180 120 100 100 80 70 70 60 40 50 NOV 160 160 160 150 150
DEC 200 170 140 130 100 80 70 60 40 50 DEC 240 230 170 200 100
mean 138 116 122 96 108 89 73 47 44 44 mean 141 163 145 135 135
std dev 42 31 38 26 28 24 16 11 21 11 std dev 36 37 35 42 42
median 145 115 120 90 105 80 70 40 40 50 median 140 160 160 135 95
max 210 170 190 150 180 140 100 60 100 60 max 240 230 200 210 210
min 80 60 70 70 70 60 40 30 20 20 min 80 90 80 60 60
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 230 160 140 60 40 200 400 120 JAN 120 140 120 100 160 150 JAN 40 20 30 30
FEB 160 30 40 60 130 50 90 210 100 FEB 50 20 50 10 60 50 FEB 60 10 30
MAR 80 50 40 70 160 40 100 280 40 MAR 40 10 30 10 40 50 MAR 50 20 10 10
APR 160 140 100 170 260 110 400 1,890 300 APR 70 30 120 60 80 110 APR 80 50 10 40
MAY 90 190 180 290 260 210 790 3,040 860 MAY 110 80 100 100 350 170 MAY 110 110 30 60
JUN 90 140 180 290 230 80 710 960 540 JUN 120 70 220 90 360 370 JUN 120 110 10 30
JUL 100 510 430 350 1,280 50 440 3,780 210 JUL 140 70 410 140 140 160 JUL 120 70 10 30
AUG 120 120 180 320 340 650 1,850 170 AUG 200 80 590 180 90 210 AUG 110 110 40 50
SEP 240 180 290 590 690 100 650 2,130 270 SEP 110 470 240 70 230 SEP 150 140 40 50
OCT 220 90 110 140 160 70 450 2,240 290 OCT 110 40 120 50 110 140 OCT 130 40 10 20
NOV 140 120 110 100 330 80 250 2,660 300 NOV 170 70 590 90 90 200 NOV 80 70 20 40
DEC 140 90 80 70 270 70 180 580 390 DEC 100 50 270 70 60 190 DEC 110 90 30 40
mean 148 152 157 209 374 82 409 1,668 299 mean 112 64 258 95 134 169 mean 97 70 23 36
std dev 54 118 106 156 321 46 237 1,129 213 std dev 46 36 197 64 104 82 std dev 33 41 12 14median140130125155260704201,870 280 median 110 70 170 90 90 165 median 110 70 25 40
max 240 510 430 590 1,280 210 790 3,780 860 max 200 140 590 240 360 370 max 150 140 40 60
min 80 30 40 60 130 40 90 210 40 min 40 10 30 10 40 50 min 40 10 10 10
38
0
20
40
60
80
100
120
140
160
180
200
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 B210 NCF6
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 mainstem stations, 1995-2009
versus 2010.
1995-2009
2010
39
Table 2.14 Orthophosphate (µg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 30 30 30 20 20 20 20 20 10 10 JAN 20 20 50 10 20 20
FEB 20 20 20 20 40 20 20 10 10 5 FEB 30 30 30 10 30 20
MAR 40 30 40 40 50 30 20 10 5 10 MAR 40 40 40 30 30
APR APR
MAY 40 40 30 20 40 10 10 10 5 20 MAY 60 70 80 50 70 40
JUN 60 60 60 40 30 50 30 20 20 10 JUN 70 70 80 40 60 30
JUL 80 80 70 50 40 30 10 10 0 10 JUL 50 90 80 40 60 40
AUG 70 60 50 50 40 40 30 20 10 20 AUG 40 110 110 70 100 50
SEP SEP
OCT 40 40 40 60 50 50 40 OCT 50 40 40 30 30 110
NOV 70 60 70 30 30 40 40 30 10 10 NOV 90 90 80 30 60 50
DEC 90 70 60 40 40 40 10 10 5 10 DEC 80 110 40 100 110 40
mean 54 49 47 37 38 33 23 16 8 12 mean 53 67 63 42 57 43
std dev 23 20 18 14 9 13 12 7 6 5 std dev 22 33 26 29 31 26
median 50 50 45 40 40 35 20 10 10 10 median 50 70 65 40 60 40
max 90 80 70 60 50 50 40 30 20 20 max 90 110 110 100 110 110min202020202010101005min202030102020
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 70 20 10 20 10 60 220 5 JAN 20 5 20 5 20 20 JAN 20 10 10 5
FEB 70 20 10 40 80 10 60 210 10 FEB 10 5 20 5 10 10 FEB 20 10 5
MAR 100 50 40 110 80 20 280 1,880 10 MAR 20 10 80 10 20 40 MAR 30 20 5
APR APR APR
MAY 20 60 40 120 120 30 670 2,940 200 MAY 40 30 100 20 20 60 MAY 40 30 10 5
JUN 20 50 40 130 60 20 480 790 310 JUN 40 30 130 20 30 70 JUN 50 50 10 10
JUL 10 60 60 60 50 10 30 2,350 60 JUL 50 30 230 10 30 30 JUL 40 30 5 5
AUG 40 40 40 150 70 5 70 1,650 50 AUG 60 30 270 10 20 110 AUG 40 40 20 5
SEP SEP SEP
OCT 170 30 30 70 70 20 240 2,140 40 OCT 60 10 70 10 40 70 OCT 80 20 5 5
NOV 80 30 40 40 110 30 20 2,340 40 NOV 40 20 240 20 90 30 NOV 40 50 20 10
DEC 70 40 30 20 80 20 70 320 230 DEC 40 20 130 30 40 110 DEC 50 30 5 5
mean 65 40 34 76 80 18 198 1,484 96 mean 38 19 129 14 32 55 mean 41 29 10 6
std dev 47 15 15 48 22 9 221 1,015 109 std dev 17 11 90 8 23 35 std dev 17 14 6 2
median 70 40 40 65 80 20 70 1,765 45 median 40 20 115 10 25 50 median 40 30 8 5
max 170 60 60 150 120 30 670 2,940 310 max 60 30 270 30 90 110 max 80 50 20 10
min 10 20 10 20 50 5 20 210 5 min 10 5 20 5 10 10 min 20 10 5 5
40
Table 2.15 Chlorophyll a (µg/l) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 3 3 3 2 2 2 2 5 4 6 JAN 6 6 3 1 6 1
FEB 4 3 3 2 3 4 3 3 4 3 FEB 10 9 9 3 5 1
MAR 5 5 6 4 3 3 3 3 4 5 MAR 6 3 4 1 3 1
APR 9 8 9 7 4 10 9 5 5 4 APR 8 7 7 2 4 2
MAY 5 8 12 24 76 23 7 4 7 MAY 11 11 9 2 4 3
JUN 5 6 6 9 10 9 14 13 13 22 JUN 7 9 7 2 4 7
JUL 7 16 5 21 20 22 33 12 9 8 JUL 39 10 6 2 4 12
AUG 5 6 14 13 10 14 13 6 6 5 AUG 47 31 23 12 17 7
SEP 6 7 7 8 10 15 8 7 7 7 SEP 24 8 3 2 6 4
OCT 1 2 2 1 3 2 2 OCT 2 1 1 1 1 0
NOV 2 2 2 3 3 3 4 3 3 5 NOV 2 1 1 0 1 1
DEC 2 2 2 3 3 4 4 4 5 4 DEC 0 0 0 0 0 1
mean 5 6 6 8 6 14 10 6 6 7 mean 14 8 6 2 5 3
std dev 2 4 4 7 5 20 9 3 3 5 std dev 15 8 6 3 4 3
median 5 6 6 6 3 7 6 5 5 5 median 8 8 5 2 4 2
max 9 16 14 24 20 76 33 13 13 22 max 47 31 23 12 17 12
min 1 2 2 1 2 2 2 3 3 3 min 0 0 0 0 0 0
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1 1 1 3 1 1 1 0 JAN 1 1 1 1 1 1 JAN 0 3 0 1
FEB 2 2 2 4 2 2 2 2 3 FEB 2 2 1 1 1 2 FEB 1 2 1
MAR 2 2 1 2 3 4 1 2 1 MAR 2 3 1 1 1 4 MAR 1 2 7 1
APR 3 2 6 2 8 4 1 2 2 APR 1 3 2 3 2 2 APR 1 2 3 8
MAY 19 2 43 8 8 7 2 1 10 MAY 1 1 1 3 1 1 MAY 1 1 1 10
JUN 28 2 5 7 42 2 4 4 3 JUN 1 1 2 5 5 3 JUN 4 1 1 11
JUL 26 8 29 34 217 3 2 29 3 JUL 2 1 2 5 5 14 JUL 11 1 0 18
AUG 47 3 7 8 39 2 4 10 AUG 3 2 5 62 1 4 AUG 11 2 1 19
SEP 49 1 16 11 34 3 1 2 23 SEP 0 14 14 1 4 SEP 3 1 2 14
OCT 2 1 3 5 25 12 0 1 1 OCT 1 0 1 2 2 1 OCT 0 0 0 1
NOV 1 1 2 2 13 5 1 1 2 NOV 1 0 3 2 5 1 NOV 0 0 0 1
DEC 4 2 1 4 3 9 1 5 1 DEC 0 1 1 1 1 1 DEC 0 0 0 1
mean 15 2 10 8 36 5 2 5 5 mean 1 1 3 8 2 3 mean 3 1 1 8
std dev 17 2 13 8 59 3 1 8 6 std dev 1 1 4 17 2 3 std dev 4 1 2 7
median 4 2 4 5 13 4 1 2 3 median 1 1 2 3 1 2 median 1 1 1 8max49843342171242923max331462514max113719
min 1 1 1 2 2 1 0 1 0 min 0 0 1 1 1 1 min 0 0 0 1
41
0
2
4
6
8
10
12
14
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210 BBT
Ch
l
o
r
o
p
h
y
l
l
a
(µg/
L
)
Figure 2.6 Chlorophyll a at the Lower Cape Fear River mainstem stations, 1995-2009
versus 2010.
1995-2009
2010
42
Table 2.16 Biochemical Oxygen Demand (mg/l) during 2010 at the Lower Cape Fear River Program stations.
5-Day Biochemical Oxygen Demand
month NC11 AC NCF117 B210 LVC2 BBT
JAN 1.2 1.7 0.8 0.7 0.8 1.0
FEB 0.9 0.9
MAR 1.2 1.4 0.9 1.0 1.8 1.0
APR 1.3 1.8 1.6 1.5 1.6 1.2MAY1.7 1.0 1.1 0.9 2.7 0.8
JUN 1.5 1.5 0.7 1.3 2.1 1.1
JUL 3.1 1.9 0.9 1.3 1.6 1.6
AUG 1.8 2.3 2.0 1.0 1.9 1.5SEP2.8 1.7 0.8 1.1 1.8 1.2
OCT 1.4 1.7 3.3 3.1 1.4
NOV 2.4 1.4 0.7
DEC 0.6 1.1 0.6 0.6 1.2 1.0
mean 1.7 1.6 1.2 1.0 1.9 1.1
stdev 0.8 0.4 0.8 0.3 0.7 0.3
median 1.5 1.7 0.9 1.0 1.8 1.1max3.1 2.3 3.3 1.5 3.1 1.6
min 0.6 1.0 0.6 0.6 0.8 0.7
20-Day Biochemical Oxygen Demand
month NC11 AC NCF117 B210 LVC2 BBT
JAN 2.9 3.5 2.3 1.5 2.2 2.1
FEB 2.0 1.8
MAR 3.2 3.8 2.8 2.0 4.6 2.7
APR 4.0 4.7 4.3 3.5 4.6 3.4
MAYJUN 2.8 3.2 2.1 3.2 5.5 2.8
JUL 6.6 5.2 2.2 3.0 4.1 3.8
AUG 4.6 7.2 3.3 2.4 5.5 3.7
SEP 5.9 5.5 2.4 2.9 5.1 3.4OCT4.7 5.3 4.9 3.6 4.2
NOV 3.5 4.6 3.5 2.4 3.9 2.4
DEC 3.5 3.4 2.6 1.9 5.8 3.6
mean 4.2 4.6 2.9 2.5 4.5 3.2
stdev 1.3 1.2 1.0 0.7 1.1 0.7
median 3.8 4.7 2.6 2.4 4.6 3.4
max 6.6 7.2 4.9 3.5 5.8 4.2min2.8 3.2 2.0 1.5 2.2 2.1
43
Table 2.17 Fecal Coliform (cfu/100 ml) during 2010 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 19 10 19 5 5 5 5 5 5 5 JAN 46 64 136 64 10
FEB 73 91 64 37 91 136 73 82 28 10 FEB 37 55 37 46 46
MAR 19 19 37 46 109 64 73 5 10 5 MAR 10 10 5 10 10
APR 5 28 28 37 5 5 10 5 5 5 APR 10 19 28 28 19
MAY 109 28 55 10 10 10 10 10 10 10 MAY 10 10 10 10 10
JUN 19 10 46 28 10 28 10 10 10 10 JUN 19 37 19 10 100
JUL 28 10 10 19 5 5 5 5 5 5 JUL 28 310 10 10 55
AUG 19 19 19 28 5 5 5 5 5 5 AUG 5 64 28 19 64
SEP 28 109 10 10 10 10 5 5 5 5 SEP 64 37 55 46 19
OCT 82 154 136 136 145 210 91 OCT 145 46 64 55 73
NOV 37 46 19 28 5 10 5 5 5 10 NOV 10 19 37 10 46
DEC 19 5 19 10 19 5 5 5 5 28 DEC 10 10 5 19 5
mean 38 44 39 33 35 41 25 13 8 9 mean 33 57 36 27 38
std dev 31 46 34 33 48 63 32 22 7 6 std dev 38 79 35 19 29
max 109 154 136 136 145 210 91 82 28 28 max 145 310 136 64 100
min 5 5 10 5 5 5 5 5 5 5 min 5 10 5 10 5
Geomean 28 26 29 23 14 15 12 7 7 8 Geomean 20 33 23 21 26
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM monthNCF117 B210 COL LVC2 SC-CH
JAN 28 100 10 64 37 91 819 19 JAN 55 136 91 37 270 390 JAN 55 64 28 163 46
FEB 163 290 37 64 390 118 172 350 352 FEB 181 64 109 46 55 154 FEB 163 46 64 64
MAR 37 46 5 10 46 10 10 199 10 MAR 10 10 28 64 28 55 MAR 46 64 28 91 37
APR 28 118 109 270 181 136 19 172 100 APR 100 5 28 10 210 910 APR 28 82 10 10 28
MAY 73 172 109 136 637 13,000 73 82 21,000 MAY 55 55 127 127 210 181 MAY 10 37 73 64 55
JUN 480 127 127 310 1,091 4,300 6,000 5,300 12,000 JUN 570 300 4,600 390 23,000 6,000 JUN 73 5 19 28 82
JUL 37 73 637 109 637 172 100 1,091 46 JUL 280 46 136 1,728 8,000 1,091 JUL 10 163 10 118 364
AUG 145 330 546 73 3,400 163 2,182 350 AUG 1,000 637 1,728 15,000 273 819 AUG 64 230 73 28 28
SEP 190 37 100 637 190 455 210 273 380 SEP 46 109 240 290 5 SEP 127 145 37 64 73
OCT 55 109 181 82 199 220 172 910 340 OCT 380 364 100 118 230 154 OCT 55 55 55 127 100
NOV 91 55 163 5 163 46 10 100 100 NOV 55 91 250 37 190 260 NOV 37 73 55 46 64
DEC 91 637 100 127 430 109 1,091 637 5,900 DEC 73 300 28 37 250 455 DEC 73 46 37 37 3,400
mean 118 175 177 157 669 1,691 676 1,010 3,383 mean 251 171 611 1,486 2,751 873 mean 62 84 41 71 362
std dev 121 165 193 170 910 3,770 1,629 1,414 6,344 std dev 288 184 1,285 4,100 6,472 1,583 std dev 43 61 22 46 920
max 480 637 637 637 3,400 13,000 6,000 5,300 21,000 max 1,000 637 4,600 15,000 23,000 6,000 max 163 230 73 163 3,400
min 28 37 5 5 46 10 10 82 10 min 10 5 28 10 28 5 min 10 5 10 10 28
Geomean 81 123 90 84 359 206 119 483 336 Geomea 127 82 144 139 346 283 Geomea 46 61 34 54 88
44
0
10
20
30
40
50
60
70
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
/
1
0
0
m
L
)
Figure 2.7 Fecal Coliform Bacteria at the Lower Cape Fear River mainstem stations,
1995-2009 versus 2010.
1995-2009
2010
45
3.0 Water Quality Evaluation by Subbasin in the Lower Cape Fear
River System
Matthew R. McIver, Michael A. Mallin, and James F. Merritt
Aquatic Ecology Laboratory
Center for Marine Science University of North Carolina Wilmington
3.0 Water Quality Evaluation by Subbasin
This section details an evaluation of water quality within each subbasin for dissolved
oxygen, turbidity, chlorophyll a, fecal coliform bacteria, nitrate-nitrite and total phosphorus
at the LCFRP sampling sites. Monthly data from January to December 2009 are used in these comparisons.
3.1 Introduction
The NC Division of Water Quality prepares a basinwide water quality plan for each of the
seventeen major river basins in the state every five years (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan October 2005). The basinwide approach is a
non-regulatory watershed based approach to restoring and protecting the quality of North
Carolina’s surface waters. The first basinwide plan for the Cape Fear River was completed
in 1996 and five-year interval updates have been completed in 2000 and 2005.
The goals of the basinwide program are to: -Identify water quality problems and restore full use to impaired waters.
-Identify and protect high value resource waters.
-Protect unimpaired waters while allowing for reasonable economic growth.
DWQ accomplishes these goals through the following objectives:
-Collaborate with other agencies to develop appropriate management strategies.
-Assure equitable distribution of waste assimilative capacity. -Better evaluate cumulative effects of pollution.
-Improve public awareness and involvement.
The US Geological Survey (USGS) identifies 6 major hydrological areas in the Cape Fear
River Basin. Each of these hydrologic areas is further divided into subbasins by DWQ. There are 24 subbasins within the Cape Fear River basin, each denoted by six digit numbers, 03-06-01 to 03-06-24 (NCDENR-DWQ, October 2005).
All surface waters in the state are assigned a primary classification that is appropriate to
the best uses of that water. North Carolina’s Water Quality Standards Program adopted
46
classifications and water quality standards for all the state’s river basins by 1963. The
program remains consistent with the Federal Clean Water Act and its amendments. DWQ assesses ecosystem health and human health risk through the use of five use
support categories: aquatic life, recreation, fish consumption, water supply and shellfish
harvesting. These categories are tied to the uses associated with the primary
classifications applied to NC rivers and streams. Waters are supporting if data and
information used to assign a use support rating meet the criteria for that use category. If
these criteria are not met then the waters are Impaired. Waters with inconclusive data and
information are Not Rated. Waters with insufficient data or information are rated No Data.
Because of state wide fish consumption advisories for several fishes, all waters in the
basin are impaired on an evaluated basis.
For ambient water quality monitoring criteria DWQ uses water quality data collected by both
their own monitoring system as well as several NPDES discharger coalitions including the
Lower Cape Fear River Program. The parameters used to assess water quality in the
aquatic life category include dissolved oxygen (DO), pH, chlorophyll a and turbidity as well
as benthos and fish data. DWQ rates use support based on whether the NC State Water
Quality Standard is exceeded as listed below:
Numerical standard exceeded in < 10% of samples = Supporting
Numerical standard exceeded in > 10% of samples = Impaired
Less than 10 samples collected = Not Rated
DO and pH standard exceeded in swamp streams = Not Rated
*Some of the NC State Water Quality standards are written with more specific criteria and the reader should refer to http://h2o.enr.state.nc.us/csu/index.htm for complete details
about the use of the standards.
3.2 Methods
The UNCW Aquatic Ecology Laboratory (AEL) has developed an evaluation system that
incorporates some of the guidelines used by DWQ and utilizes data collected by the Lower
Cape Fear River Program. This approach determines a water quality “rating” for the parameters dissolved oxygen, chlorophyll a, fecal coliform bacteria, field turbidity and the
nutrient species nitrate-nitrite (referred to as nitrate) and total phosphorus. For dissolved oxygen, chlorophyll a, and fecal coliform bacteria we compare LCFRP data to the N.C.
State Water Quality Standards (http://h2o.enr.state.nc.us/csu/index.htm). Fecal coliform
bacteria data is analyzed considering human contact standards, not shellfishing standards.
The NC DWQ does not have surface water quality standards for nitrate and total
phosphorus. The AEL water quality standard is based on levels noted to be problematic in
the scientific literature and our own published research. Based on data from four years of
nutrient addition bioassay experiments using water from the Black and Northeast Cape
Fear Rivers, Colly Creek and Great Coharie Creek, the UNCW-AEL considers total phophorus levels of 500 µg/L or greater potentially harmful to water quality in all the waters
47
of the Cape Fear River watershed. Nitrate levels of 200 µg/L, 500 µg/L and 1,000 µg/L in
small streams, mainstem blackwater stations (NCF117, NCF6, B210) and mainstem Cape Fear River stations, respectively, are considered harmful to water quality. These nutrient
levels may lead to algal blooms, high bacteria levels and high biochemical oxygen demand
(BOD) in blackwater streams (Mallin et al., 2001; 2002; 2004). Water quality status for
nutrient species at the mainstem Cape Fear River stations was evaluated with a higher
standard for nutrients because its waters are quite different than the blackwater areas and
are able to better assimilate higher nutrient levels.
AEL rates use support based on whether the NC State Water Quality Standard is exceeded
as listed below: Good = Standard is exceeded in 0 or 1 of 12 measurements (<10%) Fair = Standard is exceeded in 2 or 3 of 12 measurements (11-25%)
Poor = Standard is exceeded in 4-12 out of 12 measurements (>25%)
The 36 stations monitored by the LCFRP by subbasin:
03-06-16
Subbasin # LCFRP Stations
BRN, HAM, NC11
03-06-17 LVC2, AC, DP, IC, NAV, HB, BRR,
M61, M54, M42, M35, M23, M18, SPD
03-06-18 SR
03-06-19 6RC, LCO, GCO
03-06-20 COL, B210, BBT
03-06-21 N403
03-06-22 SAR, GS, PB, LRC, ROC
03-06-23 ANC, BC117, BCRR, NCF6, NCF117, SC-CH
Each subbasin is addressed separately with a description and map showing the LCFRP
stations. This will be followed by a summary of the information published in the October
2005 Cape Fear River Basinwide Water Quality Plan and water quality status discussion
using the UNCW-AEL approach for the 2009 LCFRP data.
48
3.3 Cape Fear River Subbasin 03-06-16
Location: Cape Fear River upstream and downstream of Elizabethtown
Counties: Bladen, Columbus, Cumberland, Pender
Water bodies: Cape Fear River
Municipalities: Elizabethtown, Dublin, White Lake, East Arcadia, Tar Heel
NPDES Dischargers: 7 @ 13.7 million gallons per day
Concentrated Swine Operations: 50
LCFRP monitoring stations (DWQ #): BRN (B8340050), HAM (B8340200), NC11 (B8360000) NC DWQ monitoring stations (DWQ #):
Six ambient monitoring stations Subbasin 03-06-16 includes the Cape Fear River
and many streams that drain coastal plain wetlands and bay lakes. Most of the
watershed is forested with some agriculture pres
49
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 101.5 freshwater miles Supporting 115.1 freshwater miles
Not Rated 40.1 freshwater miles Not Rated 4.8 freshwater miles
Not Rated 1,593.2 freshwater acres No Data 153.1 freshwater miles
No Data 131.4 freshwater miles No Data 2,510.8 freshwater acres
No Data 917.6 freshwater acres
*Brown’s Creek, rated as impaired in the 2000 CFRBWQP, was upgraded in the 2005
plan (NCDENR DWQ CFRWQBP, July 2000 and NCDENR DWQ CFRWQBP, October 2005).
Data collection: NC11 since June 1995, BRN & HAM since February 1996 Sampling relevance: Represents water entering the Lower Cape Fear River watershed
from the middle basin (NC11). There are also concentrated animal operations within the
area (BRN and HAM).
UNCW Aquatic Ecology Laboratory Evaluation
BRN - representative of small tributaries NC11 – Main stem of the Cape Fear River
deep channel, freshwater with minor tidal influence
Dissolved Oxygen ratings for BRN and NC11 were both good. At HAM the rating was fair,
with values exceeding the NC State standard 25% of the time (Table 3.3.1).
All sites within this subbasin had a good rating for chlorophyll a concentrations (Table
50
3.3.1). The North Carolina State standard for chlorophyll a, 40 µg/L, was exceeded only
once which was at NC11 in August 2010.
For fecal coliform bacteria concentrations NC11 had a good rating (Table 3.3.1). BRN and
HAM received poor ratings exceeding the standard 75% and 58% of the time, respectively
(Figure 3.3.1).
For field turbidity all stations were rated good (Table 3.3.1). The NC State Standard of 50
NTU was exceeded once at BRN in June.
For nitrate BRN and HAM received a poor rating exceeding the standard 84% and 50% of the time, respectively (Table, 3.3.1, Figure 3.3.2). A fair rating was given to NC11 for nitrate as samples exceeded the standard on two occasions in 2010. All stations rated good for
total phosphorus.
Table 3.3.1 UNCW AEL 2010 evaluation for subbasin 03-06-16
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
BRN G G P G P G
HAM F G P G P G
NC11 G G G G F G
Figure 3.3.1 Fecal coliform bacteria concentrations at the LCFRP stations BRN and HAM
for 2010. The dashed line represents the NC State Standard, 200 cfu/100 mL.
0
200
400
600
800
1,000
1,200
1,400
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
/
1
0
0
m
l
)
51
Figure 3.3.2 Nitrate concentrations at the LCFRP stations BRN and HAM for 2010. The
dashed line represents the AEL standard for nitrate, 200 ug/L.
0
200
400
600
800
1000
1200
1400
1600
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
BRN
HAM
52
53
54
3.4 Cape Fear River Subbasin 03-06-17
Location: Cape Fear River near Riegelwood, downstream to estuarine area
near Southport
Counties: Columbus, Pender, Brunswick, New Hanover
Waterbodies: Cape Fear River and Estuary
Municipalities: Wilmington, Southport NPDES Dischargers: 41 @ 99.9 million gallons per day Concentrated Swine Operations: 7
LCFRP monitoring stations (DWQ #):
LVC2 (B8445000), AC (B8450000), DP (B8460000), IC (B9030000), NAV
(B9050000), HB (B9050100), BRR (B9790000), M61 (B9750000), M54
(B9795000), M42 (B9845100), M35 (B9850100), M23 (B9910000), M18
(B9921000), SPD (B9980000)
DWQ monitoring stations:
55
Subbason 03-06-17 includes the mainstem of the Cape Fear River, the Cape Fear River
Estuary and many streams that drain the areas west of the River. Most of the watershed is forested with some urban areas including Wilmington and Southport.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 14,125.4 saltwater acres Supporting 21,092.3 saltwater acres Not Rated 2.0 saltwater acres Impaired 96.6 saltwater acres Impaired 6,457.0 saltwater acres Supporting 44.1 freshwater miles
Supporting 75.4 freshwater miles Not Rated 5.6 coast miles
Not Rated 22.3 freshwater miles Impaired 4.7 coast miles
Not Rated 406.9 freshwater acres No Data 2,254.6 saltwater acres No Data 2,859.2 saltwater acres No Data 269.1 freshwater miles No Data 215.4 freshwater miles No Data 1,251.5 freshwater acres
No Data 844.5 freshwater acres No Data 12.5 coast miles
No Data 22.8 coast miles
Data collection: Most stations since 1995, all sampled since 1998
Sampling relevance: Highly important estuary for fisheries productivity. Also receives
point source discharge and non-point source pollution.
UNCW Aquatic Ecology Laboratory Evaluation
AC – representative of riverine system HB- upper estuary, upstream of
channel Wilmington
56
M35 – represents wide estuary
Sites given a good rating for dissolved oxygen include AC, M42, M35, M23, M18 and SPD
(Table 3.4.1). Sites having a fair rating for dissolved oxygen, with the percentage of
samples not meeting the standard shown in parentheses, are DP (17%), IC(17%), NAV (17%), HB (25%), M61 (25%) and M54 (17%). LVC2 and BRR were rated poor with samples below the standard 45% and 33% of the time, respectively (Figure 3.4.1).
All sites within this subbasin had a good rating in terms of chlorophyll a concentrations
(Table 3.4.1). One sample exceeded the 40 µg/L NC State Standard during 2010: the May
sample from M42 measured 76 µg/L.
All sites within this subbasin rated good for fecal coliform bacteria during 2010 (Table 3.4.1). Only two samples exceeded the NC State Standard.
Ten of the fourteen sites within this subbasin had a good rating for field turbidity (Table
3.4.1). Four stations were rated fair including HB, BRR, M54 and M42 with all sites
exceeding the NC state standard for brackish waters of 25 NTU 17% of the time.
All sites in this subbasin rated good for nitrate except LVC2 which was rated poor for
nitrate, exceeding the UNCW-AEL recommended standard (200 mg/L for stream stations)
73% of the time (Table 3.4.1). All stations rated good for total phosphorus.
57
Table 3.4.1 UNCW AEL 20010 evaluation for subbasin 03-06-17
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
LVC2 P G G G P G
AC G G G G G G
DP F G G G G G
IC F G G G G G
NAV F G G G G G
HB F G G F G G
BRR P G G F G G
M61 F G G G G G
M54 F G G F G G
M42 G G G F G G
M35 G G G G G G
M23 G G G G G G
M18 G G G G G G
SPD G G G G G G
Figure 3.4.1 Dissolved oxygen concentrations at LVC2 and BRR, rated poor for 2010. The dashed line shows the NC State Standard of 5.0 mg/L.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
LVC2
BRR
58
3.5 Cape Fear River Subbasin 03-06-18
Location: South River headwaters above Dunn down to Black River
Counties: Bladen, Cumberland, Harnett, Johnston, Sampson
Waterbodies: South River, Mingo Swamp
Municipalities: Dunn, Roseboro
NPDES Dischargers: 2 @ 0.08 million gallons per day
Concentrated Swine Operations: 105
LCFRP monitoring stations (DWQ #): SR (B8470000) DWQ monitoring stations: none
This subbasin is located on the inner coastal plain and includes the South River which
converges with the Great Coharie Creek to form the Black River, a major tributary of the
Cape Fear River. Land use is primarily agriculture including row crops and concentrated
animal operations.
59
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Not Rated 52.1 freshwater miles Supporting 52.1 freshwater miles Not Rated 1,454.2 freshwater acres No Data 242.5 freshwater miles
No Data 242.5 freshwater miles No Data 1,454.2 freshwater acres
Data collection: Since February 1996
Sampling relevance: Below City of Dunn, hog operations in watershed
UNCW Aquatic Ecology Laboratory Evaluation
SR – a slow black water tributary
SR had a poor rating for dissolved oxygen concentrations in 2010 (Table 3.5.1). The NC
State Standard for swampwater of 4.0 mg/L was not met 50% of the time. The lowest
levels were found in summer and late fall (Figure 3.5.1).
SR had a good rating for chlorophyll a exceeding the NC State standard of 40 µg/L on
one occasion (Table 3.5.1).
SR had a poor water quality rating for fecal coliform bacteria concentrations exceeding the NC state standard of 200 CFU/100mL in 33% of samples (Table 3.5.1). The highest
concentration was in August (15,000 cfu/100mL).
SR had a good rating for field turbidity and total phosphorus (Table 3.5.1). The nitrate
rating was fair with samples exceeding the standard 25% of the time.
60
Table 3.5.1 UNCW AEL 2010 evaluation for subbasin 03-06-18
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SR P G F G F G
Figure 3.5.1 Dissolved oxygen (mg/L) at SR during 2010. The dashed line shows the NC
state standard for swampwater DO of 4.0 mg/L.
0
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3.6 Cape Fear River Subbasin 03-06-19
Location: Three main tributaries of Black River near Clinton
Counties: Sampson
Waterbodies: Black River, Six Runs Ck., Great Coharie Ck., Little Coharie Ck. Municipalities: Clinton, Newton Grove, Warsaw NPDES Dischargers: 8 @ 6.8 million gallons per day Concentrated Swine Operations: 374
LCFRP monitoring stations (DWQ #):
LCO (B8610001), GCO (B8604000), 6RC (B8740000)
DWQ monitoring stations: none
63
This subbasin is located in the coastal plain within Sampson County. Land adjacent to the Black River is primarily undisturbed forest. There are numerous concentrated swine
operations within this subbasin.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 71.3 freshwater miles Supporting 153.0 freshwater miles
Not Rated 99.7 freshwater miles Not Rated 8.8 freshwater miles
No Data 338.4 freshwater miles No Data 347.6 freshwater miles
Data collection: February 1996 to present
Sampling relevance: Many concentrated animal operations (CAOs) within the
watershed, reference areas for point and nonpoint source pollution
UNCW Aquatic Ecology Laboratory Evaluation
GCO - blackwater stream, drains riparian wetlands
6RC, LCO and GCO all had a good rating for dissolved oxygen, chlorophyll a and field
turbidity concentrations during 2010 (Table 3.6.1).
GCO had a fair rating for fecal coliform bacteria during 2010. 6RC and LCO had a poor
rating for fecal coliform bacteria with 36% and 33% of samples exceeding the NC State
human contact standard of 200 CFU/100mL, respectively (Table 3.6.1, Figure 3.6.1).
Nitrate levels were rated poor at 6RC, LCO and GCO exceeding 200 µg/L in 100%, 84%,
and 42% of the samples, respectively (Table 3.6.1, Figure 3.6.1). 6RC and LCO had a
good rating for total phosphorus concentrations, while GCO rated fair with 17% of samples
exceeding the UNCW-AEL recommended standard of 500 µg/L (Table 3.6.1).
64
Table 3.6.1 UNCW AEL 2010 evaluation for subbasin 03-06-19
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
6RC G G P G P G
LCO G G P G P G
GCO G G F G P F
Figure 3.6.1 Fecal coliform bacteria concentrations at 6RC and LCO during 2010. The
dashed line shows the NC State standard of 200 cfu/100 mL.
0
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1,400
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Figure 3.6.1 Nitrate concentrations (µg/L) at 6RC, LCO, and GCO during 2010. The
dashed line shows the UNCW-AEL standard of 200 µg/L.
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3.7 Cape Fear River Subbasin 03-06-20
Location: Lower reach of Black River
Counties: Pender
Waterbodies: Black River, Colly Creek, Moores Creek Municipalities: Town of White Lake, Currie, Atkinson NPDES Dischargers: 2 at 0.82 million gallons per day Concentrated Swine Operations: 18 LCFRP monitoring stations (DWQ #):
COL (B8981000), B210 (B9000000), BBT (none)
DWQ monitoring stations: none
70
This subbasin is located on the coastal plain in Pender County and the land is mostly
forested with some agriculture. The streams in this watershed typically have acidic black waters. The Black River in this area has been classified as Outstanding Resource Waters
(ORW) (NCDENR DWQ Cape Fear River Basinwide Water Quality Plan, October 2005).
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 13.0 freshwater miles Supporting 34.9 freshwater miles
Not Rated 77.9 freshwater miles No Data 199.8 freshwater miles Not Rated 576.0 freshwater acres No Data 576.0 freshwater miles
No Data 143.8 freshwater acres
Data collection: February 1996 to present
UNCW Aquatic Ecology Laboratory Evaluation
Sampling relevance: Colly Creek is a pristine swamp reference site, B210 and
BBT are middle and lower Black River sites
COL – blackwater stream, drains swamp area, very low pH
B210- Black River at Hwy 210 bridge
71
All three sites had a good rating for dissolved oxygen when using the NC State swampwater standard of 4.0 mg/L (Table 3.7.1).
Chlorophyll a and field turbidity concentrations were low for each site within this
subbasin and all sites had a good rating for these parameters (Table 3.7.1).
Fecal coliform bacteria concentrations were low with B210 and COL rated as good (Table 3.7.1). BBT samples were not analyzed for fecal coliform bacteria.
For nitrate COL rated good and B210 rated fair with 17% of the samples exceeding the
UNCW-AEL recommended standard of 500 µg/L. BBT samples were not analyzed for
nutrients.
Table 3.7.1 UNCW AEL 2010 evaluation for subbasin 03-06-20
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
B210 G G G G F G
COL G G G G G G
BBT G G G
72
73
3.8 Cape Fear River Subbasin 03-06-21
Location: Headwaters of NE Cape Fear River below Mount Olive
Counties: Duplin, Wayne
Waterbodies: Northeast Cape Fear River Municipalities: Mount Olive NPDES Dischargers: 6 @ 1.4 million gallons per day Concentrated Swine Operations: 75
LCFRP monitoring stations (DWQ#): NC403 (B9090000) DWQ monitoring
stations: NC403
This subbasin includes the headwaters of the Northeast Cape Fear River and small
tributaries. This section of the NE Cape Fear River is very slow moving and somewhat
congested with macrophytic growth. Most of the watershed is forested and there is
significant agriculture in the basin.
74
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 21.7 freshwater miles Supporting 57.3 freshwater miles Not Rated 38.9 freshwater miles No Data 88.1 freshwater miles
No Data 84.7 freshwater miles
Data collection: June 1997 – present Sampling relevance: Below Mount Olive Pickle Plant
UNCW Aquatic Ecology Laboratory Evaluation
NC403 - slow moving headwaters of NE Cape Fear River
NC403 had a poor rating for dissolved oxygen concentrations, not meeting the NC State
Standard for swampwater of 4.0 mg/L in 33% of the samples (Table 3.8.1, Figure 3.8.1)
NC403 had a good rating for chlorophyll a yet had very high aquatic macrophyte biomass
present, often times completely covering and blocking the waterway (Table 3.8.1). As we have noticed at several of our stations over the years, chlorophyll a, a measurement of
phytoplankton biomass, often used as an indicator of eutrophic conditions, is not always
adequate to determine problematic conditions with regard to aquatic flora.
NC403 had a fair rating for fecal coliform bacteria with samples exceeding the NC State
standard for human contact (200 cfu/100 mL) 25% of the time.
Field turbidity was rated as good at NC 403 (Table 3.8.1).
For nitrate NC403 had a poor rating with concentrations >200 µg/L for 67% of the samples
(Table 3.8.1, Figure 3.8.1). UNCW AEL researchers are concerned about the elevated
nitrate levels at this site since these levels increase the likelihood of algal blooms and excessive aquatic macrophyte growth. Total phosphorus had a good rating for 2010.
75
Table 3.8.1 UNCW AEL 2010 evaluation for subbasin 03-06-21
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
NC403 P G F G P G
Figure 3.8.1 Dissolved oxygen (mg/L) and nitrate (µg/L) concentrations at NC403 during
2010. The dashed lines show the NC State DO standard of 4.0 mg/L for swampwater and
the UNCW AEL standard for Nitrate of 200 µg/L.
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3.9 Cape Fear River Subbasin 03-06-22
Location: NE Cape Fear River and tributaries in the vicinity of Kenansville
Counties: Duplin
Waterbodies: Northeast Cape Fear River, Rockfish Creek Municipalities: Beulaville, Kenansville, Rose Hill and Wallace NPDES Dischargers: 13 @ 9.9 million gallons per day Concentrated Swine Operations: 449
LCFRP monitoring stations (DWQ #):
PB (B9130000), GS (B9191000), SAR (B9191500), LRC (9460000) ROC
(B9430000)
DWQ monitoring stations: none
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Land coverage in this watershed is mostly forested with significant agriculture including row crops and a dense concentration of animal operations (poultry and swine).
The CFR Basinwide Water Quality Plans lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting Not Rated
Impaired
No Data
51.1 freshwater miles 72.1 freshwater miles
50.1 freshwater miles
408.8 freshwater miles
Supporting Not Rated
No Data
73.2 freshwater miles 3.0 freshwater miles
505.9 freshwater miles
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: February 1996 to present
Sampling relevance: Below point and non-point source discharges
PB – slow moving swamp-like stream ROC - Rockfish Creek below Wallace
All sites in this subbasin were rated using the dissolved oxygen NC State swampwater
standard of 4.0 mg/L. SAR, PB, LRC and ROC all had a good rating (Table 3.9.1). GS had
a poor rating with DO values dropping below the standard 50% of the time.
For chlorophyll a SAR, GS, LRC and ROC had a good rating (Table 3.9.1). PB was rated
poor having concentrations exceeding the NC State standard of 40 µg/L 18% of the time.
For fecal coliform bacteria concentrations SAR, GS and ROC each had a fair rating with
25%, 17% and 25% of samples above the standard, respectively (Table 3.9.1, Figure
3.9.1). Sites PB and LRC were rated poor with 55% and 36% of samples above the
standard (Figure 3.9.2).
All sites had a good rating for field turbidity concentrations (Table 3.9.1).
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For nitrate GS had a fair rating with levels exceeding the UNCW AEL standard (200 µg/L)
25% of the time (Table 3.9.1). SAR, PB, LRC and ROC all had a poor rating with levels exceeding the UNCW AEL standard 75%, 55%, 73% and 100% of the time, respectively.
Nitrate levels for SAR, PB, LRC and ROC are shown graphically in Figure 3.9.3 and 3.9.4.
For total phosphorus PB was rated fair, exceeding the UNCW AEL standard of 500 mg/L in
18% of the samples (Table 3.9.1). ROC was rated poor, exceeding the standard 33% of the
time.
Table 3.9.1 UNCW AEL 2010 evaluation for subbasin 03-06-22
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SAR G G F G P G
GS P G F G F G
PB G F P G P F
LRC G G P G P G
ROC G G F G P P
Figure 3.9.1 Fecal coliform bacteria (cfu/100mL) at SAR, GS and ROC which rated poor
during 2010. The dashed line is the NC State Standard for human contact of 200 cfu/100mL).
0
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Figure 3.9.2 Fecal coliform bacteria (cfu/100mL) at LRC and PB which rated poor during 2010. The dashed line is the NC State Standard for human contact of 200 cfu/100mL.
Figure 3.9.3 Nitrate-N concentrations (µg/L) at SAR and PB which rated poor during 2010.
The dashed line represents the UNCW AEL standard of 200 µg/L.
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Figure 3.9.4 Nitrate-N concentrations (µg/L) at LRC and ROC which rated poor during
2010. The dashed line represents the UNCW AEL standard of 200 µg/L.
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3.10 Cape Fear River Subbasin 03-06-23
Location: Area near Burgaw and Angola swamp
Counties: Pender
Waterbodies: Northeast Cape Fear River,Burgaw Creek Municipalities: Burgaw NPDES Dischargers: 7 @ 3.8 million gallons per day Concentrated Swine Operations: 52
LCFRP monitoring stations (DWQ #):
ANC (69), BCRR (82), BC117 (83), NCF117 (84), NCF6 (85)
DWQ monitoring stations: NCF117
This subbasin is located in the outer coastal plain where many streams are slow flowing
blackwater streams that often dry up during the summer months. Most of the watershed is
84
forested with some agriculture and increasing human development.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 73.8 freshwater miles Supporting 39.5 freshwater miles
Not Rated 45.1 freshwater miles Supporting 1.0 saltwater acre
Impaired 23.4 freshwater miles Not Rated 11.6 freshwater miles
No Data 233.2 freshwater miles Not Data 324.5 freshwater miles
Not Rated 1.0 saltwater acre
UNCW Aquatic Ecology Laboratory Evaluation
NCF117 - Northeast Cape Fear River at US117
Data collection: NCF117 & NCF6 since June 1995, others from February 1996
Sampling relevance: point and non-point source dischargers
ANC - Angola Creek BC117 - Burgaw Canal at US 117
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For dissolved oxygen SC-CH had a good rating when using the 4.0 mg/L standard (Table
3.10.1). BC117, NCF117 and NCF6 had a fair rating with 17% of samples sub-standard for all three sites. ANC and BCRR had a poor rating with sub-standard samples 42% and
67% of the time, respectively (Figure 3.10.1).
For chlorophyll a BC1117, BCRR, NCF117 and NCF6 were all rated good (Table 3.10.1).
ANC was rated poor, exceeding the NC State standard of 40 µg/L 17% of the time.
Chlorophyll a was not analyzed at SC-CH.
For fecal coliform bacteria ANC, NCF117 and NCF6 had a good rating (Table 3.10.1). SC-CH was rated fair, exceeding the NC State human contact standard 17% of the time.
BC117 and BCRR each had a poor rating exceeding the human contact standard 67%
and 58% of the time, respectively (Figure 3.10.1).
All five stations were rated good for field turbidity during 2010 (Table 3.10.1).
Nutrient loading of nitrate and total phosphorus was problematic at BC117 which had a
poor rating for both (Table 3.10.1). Nitrate levels exceeded the UNCW AEL standard 100%
of the time and total phosphorus levels exceeded the UNCW AEL standard 75% of the
time. BC117 had the highest nitrate and TP levels seen in the LCFRP system. These levels
were far above the concentrations known to lead to algal bloom formation, bacterial
increases and increased biochemical oxygen demand (BOD) in blackwater streams (Mallin
et al. 2001, Mallin et al. 2002). All other sites were rated fair for nitrate exceeding the
UNCW AEL standard 25% of the time. ANC, NCF117 and NCF6 were rated good for total phosphorus. BCRR was rated fair for total phosphorus, exceeding the UNCW AEL
recommended standard 17% of the time. Nutrients were not analyzed at SC-CH.
Table 3.10.1 UNCW AEL 2010 evaluation for subbasin 03-06-23
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
ANC P F G G F G
BC117 F G P G P P
BCRR P G P G F F
NCF117 F G G G F G
NCF6 F G G F F G
SC-CH G F G
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Figure 3.10.1 Fecal coliform bacteria concentrations (cfu/100mL) at BC117 and BCRR which rated poor during 2010. The dashed line shows the NC State Standard for human
contact, 200 cfu/100 mL.
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3.11 References Cited
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.
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
Applications14: 823-838.
NCDENR-DWQ (North Carolina Department of Environment and Natural
Resources-Division of Water Quality), Cape Fear River Basinwide Water Quality Plan. July 2000, Raleigh, N.C.
NCDENR-DWQ (North Carolina Department of Environment and Natural
Resources-Division of Water Quality), Cape Fear River Basinwide Water Quality
Plan. October 2005, Raleigh, N.C.
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