Lower Cape Fear River Program 2011 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2011
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
September 2012
CMS Report No. 12-03
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
The Port of Wilmington
Alligator on the Black River 2011
Spring 2012 UNCW
Estuarine Biology
class
Rock arch at Lock and Dam #1 under
construction to improve fish passage
Dredging the shipping channel UNCW researchers sampling the
river plume
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 lower Cape Fear, Black, and Northeast Cape Fear River watersheds. The LCFRP sampling
program includes physical, chemical, and biological water quality measurements and
analyses of the benthic and epibenthic macroinvertebrate communities, and has in the
past included assessment of the fish communities. Principal conclusions of the UNCW
researchers conducting these analyses are presented below, with emphasis on water quality of the period January - December 2011. 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 2011 were similar to the average for 1995-2010. 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 2011 DO levels occurred at
the lower river and upper estuary stations DP, IC, NAV, HB, BRR and M61 (6.8-7.6
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 2011 Stations NCF117 and B210,
representing those rivers, had average DO concentrations of 5.3 and 6.9 mg/L, respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2011. Station BCRR (upper Burgaw Creek) had DO levels
below 4.0 mg/L 75% of the occasions sampled, with SR (South River) and GS (Goshen
Swamp) 58%, LVC2 (Livingston Creek) 42%, ANC (Angola Creek) 50% and NC403
(Northeast Cape Fear River headwaters) 67% below standard. Considering all sites sampled in 2011, we rated 17% as poor for dissolved oxygen, 28% as fair, and 55% as
good, a slight improvement from 2010
Annual mean turbidity levels for 2011 were lower than the long-term average in all river
and estuary stations. Highest mean turbidities were at the river sites NC11 (17 NTU) and AC (15 NTU) and the upper estuary sites NAV (21 NTU) and HB (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), 6RC (Six Runs Creek), SAR (Sarecta), and GCO (Great Coharie Creek) and
LCO (Little Coharie Creek). Average chlorophyll a concentrations were larger than
usual, particularly from June through August 2011; during this same period river flow as measured by USGS at Lock and Dam #1 was lower for 2011 compared with the 1995-
2010 long-term average (1,210 CFS compared with 3,580 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.
Stream algal blooms exceeding the State standard of 40 µg/L in 2011 occurred at ANC, NC403, 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 produce toxins, and their occurrence in bloom formation has occurred every summer since 2009. 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), 6RC, LRC and SC-CH 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 2.8 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 2011 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 97% of the stations as good and 3% fair in terms of
chlorophyll a. For turbidity 92% of the sites were rated good and 8% fair. Fecal
coliform bacteria counts showed slightly worse water quality in 2011 compared to 2009, with 49% of the sites rated as poor to fair compared with 43% in 2010. 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, 45% of the sites were
rated poor or fair for dissolved oxygen, about the same as in 2010. 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…………………46
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 2011.
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
16-year (1995-2011) 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 9,164 square miles) is the most heavily industrialized in North
Carolina with 203 permitted wastewater discharges with a permitted flow of
approximately 429 million gallons per day, and (as of 2010) over 2.07 million people residing in the basin (NCDENR Basinwide Information Management System (BIMS) &
2010 Census). Approximately 23% of the land use in the watershed is devoted to
agriculture and livestock production (2006 National Land Cover Dataset), with livestock
production dominated by swine and poultry operations. Thus, the watershed receives
considerable point and non-point source loading of pollutants. However, the estuary is a well-flushed system, with flushing time ranging from 1 to 22 days with a median
flushing time of about seven days, much shorter than the other large N.C. estuaries to
the north (Ensign et al. 2004).
Water quality is monitored by boat at 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). We note that after July 2011 sampling was discontinued at stations M42 and
SPD, per agreement with the North Carolina Division of Water Quality. 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). 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/cms/aelab/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, 2011, 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
4
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
5
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 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 2011 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. By agreement with N.C. Division of Water Quality, after June
2011 sampling was discontinued at stations M42 and SPD.
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 (i.e. from bridges or docks) the physical parameters were measured at a depth of 0.1 m.
8
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 by a State-certified laboratory contracted by the LCFRP. Samples were collected approximately 0.1 m below the surface in sterile plastic bottles provided by the contract laboratory and placed on ice for no more than six hours
before analysis. After August 2011 the fecal coliform analysis was changed to
Enterococcus in the estuarine stations downstream of NAV and HB.
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 2011. 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 0.8 to 32.2oC, and individual station annual
averages ranged from 15.9 to 21.8oC (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. Colly Creek was dry June-August so no data
were collected from that site in summer.
Salinity
Salinity at the estuarine stations (NAV through SPD) ranged from 0.1 to 35.1 practical
salinity units (psu) and station annual means ranged from 4.5 to 30.3 psu (Table 2.2).
Lowest salinities occurred in early spring and December and highest salinities occurred in mid-summer. The annual mean salinity for 2011 was higher than that of the fifteen-year
average for 1995-2010 for all of the estuarine stations (Figure 2.1). Two stream stations,
NC403 and PB, had occasional oligohaline conditions due to discharges from pickle
production facilities. SC-CH is a tidal creek that enters the Northeast Cape Fear River
upstream of Wilmington and salinity there ranges widely, from freshwater to salinity exceeding 18 psu.
Conductivity
Conductivity at the estuarine stations ranged from 0.17 to 53.24 mS/cm and from 0.07 to 10.43 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. Conductivity
at PB was exacerbated in June and July following a May 10 waste pond spill at Bay Valley
Foods. 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 8.7 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. PB had the highest maximum pH concentration in 2011 (8.7); this was the result
of a waste pond spill at Bay Valley Foods in May. We also note that LRC had unusually
high pH levels (8.3) in June and August 2011 (Table 2.3).
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Dissolved Oxygen
Dissolved oxygen (DO) problems have been a major water quality concern in the lower
Cape Fear River and its estuary, and several of the tributary streams (Mallin et al. 1999;
2000; 2001a; 2001b; 2002a; 2002b; 2003; 2004; 2005a; 2006a; 2006b; 2007; 2008; 2009; 2010; 2011). Surface concentrations for all sites in 2011 ranged from 0.2 to 14.5 mg/L
and station annual means ranged from 4.5 to 9.9 mg/L (Table 2.5). Average annual DO
levels at the river channel and estuarine stations for 2011 were mostly higher than the
average for 1995-2010 (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 M23 (note that DO concentrations are higher at M42 due
to cessation of sampling during mid-to-late summer). Lowest mainstem mean 2011 DO
levels occurred at the river and upper estuary stations IC, NAV, HB, BRR and M61 (6.8-7.2 mg/L). NAV, HB and IC were both below 5.0 mg/L on 25% of occasions sampled and
M61, BRR, DP and BBT were below on 17%, an improvement from 2010. Based on
number of occasions the river stations were below 5 mg/L UNCW rated IC, NAV, HB, BRR
and M61 as fair for 2011; 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 2011 mean = 5.3, NCF6 = 6.3, B210 2011 mean = 6.9), a worsening from 2010 . 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
12
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).
Several stream stations were severely stressed in terms of low dissolved oxygen during the year 2011. Station BCRR had DO levels below 4.0 mg/L 75% of the occasions
sampled, with NC403 67%, SR and GS 58% and ANC and LVC2 42% (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 and widespread problem, with 45% of the sites
impacted in 2011.
Field Turbidity
Field turbidity levels ranged from 1 to 61 Nephelometric turbidity units (NTU) and station
annual means ranged from 2 to 21 NTU (Table 2.6). The State standard for estuarine
turbidity is 25 NTU. Annual mean turbidity levels for 2011 were lower than the long-term
average at all estuary sites (Fig. 2.3). Highest mean and median turbidities were at NAV
and HB (16-21 NTU) with turbidities generally low in the middle to lower estuary (Figure 2.3). Station HB and Station SC-CH each exceeded the turbidity standard on two
occasions. 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 PB, SR and to a lesser extent BCRR 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 157 mg/L with station annual means from 2 to 27 mg/L (Table 2.7). The overall highest river values were at NAV and SPD. In the stream stations TSS was generally considerably lower than the river and
estuary, except for Station PB with unusually high values, prompted at least in some cases
by the May waste pond spill at Bay Valley Foods. 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
13
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.
The fine silt and clay in the upper to middle estuary sediments are most likely derived from the Piedmont and carried downstream to the estuary, while the sediments in the lowest
portion of the estuary are marine-derived sands (Benedetti et al. 2006).
Light Attenuation
The attenuation of solar irradiance through the water column is measured by a logarithmic
function (k) per meter. The higher this light attenuation coefficient is the more strongly light
is attenuated (through absorbance or reflection) in the water column. River and estuary
light attenuation coefficients ranged from 0.81 to 5.99/m and station annual means ranged
from 1.41 at M18 to 3.95 /m at NCF6 (Table 2.8). Elevated mean and median light attenuation occurred from AC downstream to IC; the estuary from NAV-M54 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; Dubbs and Whalen 2008).
Chemical Parameters – Nutrients
Total Nitrogen
Total nitrogen (TN) is calculated from TKN (see below) plus nitrate; it is not analyzed in the
laboratory. TN ranged from 70 to 31,650 g/L and station annual means ranged from 334
to 20,305 g/L (Table 2.9). Mean total nitrogen in 2011 was slightly less than the fifteen-
year mean at most river and estuary stations, except the uppermost ones NC11-IP (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 DP, entering the system, then declined 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 24,825 g/L, likely from the
upstream Town of Burgaw wastewater discharge. PB, ROC, LVC2, SAR, ANC, GCO and 6RC also had comparatively high TN values among the stream stations.
14
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 31,600 g/L and station annual means ranged from 26 to 20,034 g/L (Table 2.10). The
highest average riverine nitrate levels were at NC11 and AC (889 and 897 g/L,
respectively) indicating that much of this nutrient is imported from upstream. Moving
downstream, nitrate levels decrease most likely as a result of uptake by primary producers,
microbial denitrification in riparian marshes and tidal dilution. Despite this, the rapid flushing of the estuary (Ensign et al. 2004) permits sufficient nitrate to enter the coastal
ocean in the plume and contribute to offshore productivity (Mallin et al. 2005b). Nitrate can
limit phytoplankton production in the lower estuary in summer (Mallin et al. 1999). The
blackwater rivers carried lower concentrations of nitrate compared to the mainstem Cape
Fear stations; i.e. the Northeast Cape Fear River (NCF117 mean = 275 g/L) and the
Black River (B210 = 218 g/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, 6RC, GCO, SAR, LVC2 and NC403. LVC2 and NC403 are downstream of industrial
wastewater discharges and 6RC, ROC, GCO and SAR 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 4,670 g/L and station annual
means ranged from 7 to 721 g/L (Table 2.11). River areas with the highest mean ammonium levels this monitoring period included AC and DP, which are downstream of a
pulp mill discharge, and 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 PB, LVC2, ANC, BCRR and ROC (Table 2.11). PB had the highest mean and median concentrations in 2011; these were the result of a waste pond spill at
bay Valley Foods in May that impacted stream water quality through September.
15
Total Kjeldahl Nitrogen
Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen
plus ammonium. TKN ranged from 50 to 7,200 g/L and station annual means ranged
from 271 to 1,833 g/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 7,200 µg/L of TN was seen at PB in August. Station PB had the highest
mean and median concentrations; other sites with elevated TKN included ANC, GS,
BCRR, SR and ROC.
Total Phosphorus
Total phosphorus (TP) concentrations ranged from below detection limit to 5,080 g/L and
station annual means ranged from 25 to 2,893 g/L (Table 2.13). Mean TP for 2011 was somewhat below the fifteen-year mean in the estuary and lower river stations, but higher in
the blackwater rivers (Figure 2.5). In the river TP is highest at the upper riverine channel
station AC 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 g/L) to be potentially
problematic to blackwater streams (Mallin et al. 1998; 2004). Streams periodically
exceeding this critical concentration included BC117, GCO, ROC and PB. Some of these
stations (BC117, PB) are downstream of industrial or wastewater discharges, while GCO and ROC are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 3,750 g/L and station annual means ranged
from 6 to 2,048 g/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
16
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.
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 in summer at a few locations (Table 2.15). At many of the river
and estuarine stations chlorophyll a for 2011 was considerably higher than the fifteen-year
mean for those sites (Figure 2.6). Highest chlorophyll a concentrations on the river occurred at Station NC11. 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 is of human health as well as ecological interest was that
blooms of cyanobacteria (blue-green algae) called Microcystis aeruginosa began occurring
in 2009 and continued to occur in summer 2010 and 2011. This species contains many strains long known to produce toxins, both as a threat to aquatic life and to humans as well
(Burkholder 2002). At least some of the blooms in the main stem of the Cape Fear have
produced toxins. The North Carolina Division of Public Health had a 2009 bloom sample
from Lock and Dam #1 tested and it came out positive for 73 ppb (g/L) of microcystin (Dr. Mina Shehee, NC Division of Public Health, memo September 25, 2011), resulting in an
advisory to keep children and dogs from swimming in the waters. For comparison, the
World Health Organization has a guideline of < 1.0 g/L of microcystin-LR for drinking
water. Additionally, a UNCW Marine Science student directed by chemist Dr. Jeff Wright isolated two hepatotoxins, microcystin LR and microcystin RR, from Cape Fear Microcystis
aeruginosa blooms in 2010 (Isaacs 2011). We note that the City of Wilmington receives
their drinking water from the river above Lock and Dam #1.
The 2011 bloom persisted for a number of weeks before dissipating. In 2011 there was also a series of blooms on the Northeast Cape Fear River upstream of our sampling sites reported by NC DWQ (Stephanie Petter Garrett, personal communication); these blooms
led to local hypoxia in the affected waters. These blooms are primarily a surface
phenomenon, thus not captured by the required sampling technique (photic zone.
Presently (summer 2012) there are special projects ongoing by two UNCW researchers, Dr. Mike Mallin and Dr. Larry Cahoon, aimed at gaining further understanding of how these blooms affect the river’s ecology.
17
System wide, chlorophyll a ranged from undetectable to 91 g/L and station annual means
ranged from 2-20 g/L, lower than in 2010. 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, besides Station NC11 along the mainstem high values are normally found in the
mid-to-lower estuary stations because light becomes more available downstream of the
estuarine turbidity maximum (Fig. 2.6). On average, flushing time of the Cape Fear
estuary is rapid, ranging from 1-22 days with a median of 6.7 days (Ensign et al. 2004). This does not allow for much settling of suspended materials, leading to light limitation of
phytoplankton production. However, under lower-than-average flows there is generally
clearer water through less suspended material and less blackwater swamp inputs. For the
growing season May-September, long-term (1995-2010) average monthly flow at Lock and
Dam #1 was approximately 3,580 CFS (USGS data; (http://nc.water.usgs.gov/realtime/real_time_cape_fear.html), whereas for 2011 it was well
below that at approximately 1,210 CFS. Thus, chlorophyll a concentrations in the river and
estuary were greater than the average for the preceding fifteen years (Figure 2.6).
Substantial phytoplankton blooms occasionally occur at the stream stations, with a few occurring summer-fall in 2011 (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). In particular, Station SR had three
blooms exceeding the state standard 40 µg/L in 2011 (46, 83 and 91 g/L); single blooms exceeding the standard also occurred at ANC, NC 403 and PB (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
2011 (as was the case with 2007 through 2010) there was 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
2011 BOD5 values ranged from 0.5 – 4.5 mg/L. NCF117 mean BOD5 was 1.8 mg/L, considerably higher than the 1.2 mg/L mean at Black River B210. Stations LVC2 had the
highest mean and median BOD5 and BOD20 concentrations in 2011. BOD20 values
showed similar patterns to BOD5 in 2011.
18
Fecal Coliform Bacteria
Fecal coliform (FC) bacterial counts ranged from 1 to 60,000 CFU/100 mL and station
annual geometric means ranged from 6 to 875 CFU/100 mL (Table 2.17). The state human contact standard (200 CFU/100 mL) was exceeded at the mainstem sites only
rarely in 2011, once in June at DP, once in July at NAV, and once in November at AC.
Geometric mean fecal coliform counts in 2011 in the Cape Fear, Black, and Northeast
Cape Fear Rivers as well as the estuary were somewhat lower compared with the fifteen-
year average (Figure 2.7). Enterococcus counts, initiated in the estuary in mid-2011, were generally low in 2011.
During 2011 PB exceeded 200 CFU/100 mL 83% of the time; HAM 67%, BCRR and
BC117 58%, BRN 50%, LRC 45%, and 6RC and SC-CH 33% 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. PB in particular had counts of 60,000 CFU/100
mL on two occasions, May and August. Overall, elevated fecal coliform counts are
problematic in this system, with 49% of the stations impacted in 2011, slightly higher than
the previous year 2010.
2.4 - References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed.
American Public Health Association, Washington, D.C.
Benedetti, M.M., M.J. Raber, M.S. Smith and L.A. Leonard. 2006. Mineralogical indicators of alluvial sediment sources in the Cape Fear River basin, North Carolina. Physical Geography 27:258-281. Burkholder. J.M. 2002. Cyanobacteria. In “Encyclopedia of Environmental Microbiology” (G. Bitton, Ed.), pp 952-982. Wiley Publishers, New York. Dubbs, L. L. and S.C. Whalen. 2008. Light-nutrient influences on biomass, photosynthetic potential and composition of suspended algal assemblages in the middle Cape Fear River, USA. International Review of Hydrobiology 93:711-730. Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511. Isaacs, J.D. 2011. Chemical investigations of the metabolites of two strains of toxic cyanobacteria. M.S. Thesis, University of North Carolina Wilmington, Wilmington, N.C. 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.
19
Mallin, M.A. 2000. Impacts of industrial-scale swine and poultry production on rivers and estuaries. American Scientist 88:26-37.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1997. Nutrient
limitation and eutrophication potential in the Cape Fear and New River Estuaries.
Report No. 313. Water Resources Research Institute of the University of North Carolina,
Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 1998. Effect of organic and
inorganic nutrient loading on photosynthetic and heterotrophic plankton communities in
blackwater rivers. Report No. 315. Water Resources Research Institute of the
University of North Carolina, Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1999. Alternation
of factors limiting phytoplankton production in the Cape Fear Estuary. Estuaries
22:985-996.
Mallin, M.A., M.H. Posey, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S. Williams, M.L. Moser and J.F. Merritt. 2000. Environmental Assessment of the Lower Cape Fear River
System, 1999-2000. CMS Report No. 00-01, Center for Marine Science, University of
North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 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.
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.
20
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.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2011. Environmental Assessment of the Lower
Cape Fear River System, 2010. CMS Report No. 11-02, 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
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 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 5.2 5.8 5.9 6.1 6.3 6.6 7.1 7.2 7.2 7.1 JAN 5.0 5.7 5.1 5.1 5.0 6.1
FEB 6.8 7.0 7.3 7.4 7.3 7.5 7.7 8.0 8.0 8.6 FEB 8.6 8.6 8.5 8.8 8.8 9.2
MAR 14.3 14.4 14.0 14.1 14.4 13.9 14.3 13.9 13.0 13.7 MAR 13.0 13.3 13.8 14.0 14 15.0
APR 20.1 21.8 20.9 20.6 20.7 20.7 20.5 20.1 19.5 19.7 APR 14.2 14.3 15.1 15.7 16.8 17.1
MAY 23.9 25.1 24.0 24.1 23.8 24.0 23.6 23.6 23.1 23.1 MAY 22.7 22.6 22.4 22.4 23 23.4
JUN 29.3 28.6 29.2 29.3 28.6 28.4 28.2 27.3 27.0 27.8 JUN 29.3 29.3 29.2 28.9 29.5 29.1
JUL 29.4 29.5 29.6 29.6 29.6 29.5 29.3 29.3 JUL 30.0 30.2 30.1 30.1 30.1 29.7
AUG 31.3 31.1 31.1 31.2 31.0 30.8 30.3 30.4 AUG 32.2 31.2 31.0 31.1 31.4 31.0
SEP 27.3 27.5 27.7 27.6 27.7 28.1 28.0 27.8 SEP 28.4 28.1 27.3 27.3 28.2 27.4
OCT 22.7 22.9 22.5 22.0 22.3 23.0 22.8 22.9 OCT 22.4 22.3 22.4 20.6 22.1 22.2
NOV 16.1 16.6 16.8 16.5 16.5 17.0 16.8 16.6 NOV 15.8 16.2 16.2 15.5 16.5 17.3
DEC 12.3 12.6 13.2 13.7 14.0 14.3 14.7 14.7 DEC 13.5 13.8 13.8 13.4 13.7 14.9
mean 19.9 20.2 20.2 20.2 20.2 16.9 20.3 20.2 20.0 16.7 mean 19.6 19.6 19.6 19.4 19.9 20.2
std dev 8.9 8.8 8.7 8.6 8.5 9.0 8.3 8.1 8.1 8.2 std dev 9.1 8.8 8.7 8.7 8.8 8.2
median 21.4 22.4 21.7 21.3 21.5 17.3 21.8 21.5 21.2 16.7 median 19.1 19.3 19.3 18.2 19.5 19.8
max 31.3 31.1 31.1 31.2 31.0 28.4 30.8 30.3 30.4 27.8 max 32.2 31.2 31.0 31.1 31.4 31.0
min 5.2 5.8 5.9 6.1 6.3 6.6 7.1 7.2 7.2 7.1 min 5.0 5.7 5.1 5.1 5.0 6.1
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 4.6 3.3 4.1 4.4 4.1 5.3 3.4 6.1 3.5 JAN 2.2 1.8 1.3 0.8 2.8 2.4 JAN 5.2 5.1 4.8 6.4
FEB 10.7 10.5 10.3 10.9 8.9 10.6 11.8 10.1 10.8 FEB 7.7 7.6 7.3 7.3 7.6 7.7 FEB 11.4 10.2 12.3 11.9
MAR 9.8 8.8 9.5 9.9 8.7 9.9 8.7 9.1 8.4 MAR 11.6 11.6 11.0 10.6 12.1 11.4 MAR 14.9 14.4 12.6 14.6 14.8
APR 22.8 23.3 23.9 23.4 24.0 22.4 21.6 20.5 18.9 APR 17.1 17.3 17.3 17.0 17.3 16.5 APR 16.0 15.2 13.6 16.0 16.6
MAY 19.1 19.6 19.7 20.3 23.7 24.7 20.0 21.8 18.2 MAY 19.2 19.4 20.1 18.5 19.2 18.0 MAY 23.1 21.7 19.8 22.2 23.6
JUN 27.6 28.1 29.0 26.8 31.6 28.8 26.5 25.1 23.2 JUN 23.8 23.5 24.6 24.8 23.5 22.5 JUN 28.6 28.7 26.9 28.9
JUL 27.0 28.2 30.1 27.4 31.1 27.7 27.2 25.2 JUL 27.2 27.5 28.7 28.7 26.2 25.6 JUL 30.7 30.8 28.6 30.8
AUG 24.7 25.6 25.3 24.8 27.8 26.3 25.1 24.3 23.5 AUG 27.7 27.5 29.0 31.3 26.8 28.0 AUG 30.8 30.0 28.3 30.5
SEP 21.0 20.6 20.9 20.5 21.1 21.1 20.2 22.7 20.3 SEP 23.3 23.1 22.7 24.3 22.3 21.9 SEP 25.5 26.1 24.2 25.4 27.5
OCT 15.8 15.2 15.3 14.5 15.3 14.6 14.6 17.9 15.9 OCT 15.8 16.1 16.0 17.2 15.7 15.4 OCT 20.7 18.3 15.2 18.1 21.0
NOV 17.3 17.8 19.7 16.8 19.0 19.8 15.5 20.1 13.9 NOV 10.8 10.5 10.7 12.3 11.3 10.7 NOV 15.6 13.0 9.5 13.2 15.8
DEC 8.1 7.2 6.9 7.0 5.2 6.3 6.7 9.7 8.4 DEC 12.9 12.9 12.9 12.7 12.2 11.3 DEC 12.1 9.7 8.2 9.7 12.4
mean 17.4 17.4 17.9 17.2 18.4 17.3 16.8 17.9 15.9 mean 16.6 16.6 16.8 17.1 16.4 16.0 mean 21.8 18.7 13.2 18.3 20.0
std dev 7.7 8.4 8.7 7.9 9.8 8.3 8.0 7.2 6.9 std dev 8.0 8.0 8.6 9.0 7.5 7.6 std dev 7.0 8.6 5.9 7.9 8.2
median 18.2 18.7 19.7 18.6 20.1 19.8 17.8 20.3 17.1 median 16.5 16.7 16.7 17.1 16.5 16.0 median 21.9 16.8 12.6 17.1 18.8
max 27.6 28.2 30.1 27.4 31.6 28.8 27.7 27.2 25.2 max 27.7 27.5 29.0 31.3 26.8 28.0 max 30.8 30.8 24.2 28.6 30.8
min 4.6 3.3 4.1 4.4 4.1 5.3 3.4 6.1 3.5 min 2.2 1.8 1.3 0.8 2.8 2.4 min 12.1 5.2 5.1 4.8 6.4
22
Table 2.2 Salinity (psu) during 2011 at the Lower Cape Fear River Program estuarine stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6 SC-CH
JAN 5.2 8.8 7.9 13.7 15.7 18.9 23.9 26.3 31.6 29.5 3.4 1.2
FEB 1.2 5.0 4.8 10.1 10.4 12.7 15.5 24.1 28.2 28.1 0.1 0.3
MAR 0.1 2.3 4.9 7.6 9.3 10.3 13.3 22.0 25.2 27.9 0.1 1.6
APR 0.1 0.5 1.3 2.6 6.6 10.9 18.4 25.9 31.7 25.9 0.1 0.3
MAY 0.1 1.7 2.1 5.1 7.7 11.6 16.5 23.1 28.2 26.6 0.8 2.2
JUN 10.1 15.9 12.8 16.5 19.6 22.2 26.3 32.4 33.9 31.4 7.2 9.2
JUL 12.3 13.6 14.5 18.5 21.3 25.8 31.8 33.0 13.5 15.3
AUG 9.0 12.5 16.5 20.2 22.4 27.6 33.1 35.0 19.4 18.5
SEP 0.1 0.4 1.3 3.6 4.3 8.9 18.1 23.3 3.9 0.5
OCT 14.1 14.8 15.9 20.3 21.5 28.3 35.1 35.1 0.3 1.4
NOV 6.3 10.4 9.4 16.0 17.7 25.4 30.1 34.5 4.1 8.4
DEC 0.1 0.2 2.6 7.3 7.5 14.3 21.0 23.8 1.6 6.6
mean 4.9 7.2 7.8 11.8 13.7 14.4 20.4 26.9 30.3 28.2 4.5 5.5
std dev 5.3 6.1 5.8 6.5 6.7 4.9 6.6 5.5 4.4 2.0 6.1 6.2
median 3.2 6.9 6.4 11.9 13.1 12.2 21.2 26.1 31.7 28.0 2.5 1.9
max 14.1 15.9 16.5 20.3 22.4 22.2 28.3 35.1 35.1 31.4 19.4 18.5
min 0.1 0.2 1.3 2.6 4.3 10.3 8.9 18.1 23.3 25.9 0.1 0.3
23
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1995-2010 2011
24
Table 2.3 Conductivity (mS/cm) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 9.03 15.27 13.72 22.96 25.87 30.67 38.04 41.60 49.00 46.09 JAN 0.15 0.18 0.21 0.20 0.22 6.41
FEB 2.39 9.04 8.62 17.11 17.63 21.32 25.54 38.28 44.16 43.90 FEB 0.14 0.17 0.16 0.09 0.12 0.13
MAR 0.23 4.28 8.75 13.17 15.84 17.40 22.06 34.96 39.51 43.24 MAR 0.17 0.22 0.21 0.14 0.18 0.22
APR 0.27 0.89 2.43 4.84 11.53 18.35 29.69 40.45 48.48 40.49 APR 0.12 0.13 0.13 0.12 0.14 0.20
MAY 0.27 3.19 4.00 9.16 13.40 19.43 26.89 36.64 43.61 41.54 MAY 0.14 0.15 0.16 0.15 0.16 1.57
JUN 17.16 26.15 21.49 27.00 31.62 35.43 41.19 49.62 51.63 48.30 JUN 0.15 0.16 0.30 0.20 0.25 12.68
JUL 21.61 22.61 24.10 30.09 34.10 40.47 48.83 50.51 JUL 0.13 0.11 0.27 0.26 0.35 25.43
AUG 15.57 21.01 27.03 32.58 35.71 43.12 50.62 53.24 AUG 0.20 0.32 0.34 0.34 2.52 31.32
SEP 0.28 0.79 2.50 6.60 7.86 15.36 29.37 36.86 SEP 0.18 0.37 0.23 0.23 0.34 7.22
OCT 23.22 24.39 25.99 32.26 34.31 43.86 48.26 53.15 OCT 0.16 0.29 0.29 0.16 0.23 0.54
NOV 11.07 17.54 16.04 26.09 28.66 39.57 46.24 52.37 NOV 0.21 0.33 0.37 0.24 0.30 7.32
DEC 0.17 0.46 4.78 12.67 12.93 23.63 33.49 37.52 DEC 0.16 0.20 0.23 0.22 0.25 3.05
mean 8.44 12.13 13.29 19.54 22.45 23.77 32.45 41.53 46.67 43.93 mean 0.16 0.22 0.24 0.20 0.42 8.01
std dev 9.04 10.08 9.43 10.17 10.26 7.46 9.68 7.14 6.12 2.89 std dev 0.03 0.09 0.08 0.07 0.66 10.35
median 5.71 12.16 11.23 20.03 21.75 20.37 33.86 41.03 48.74 43.57 median 0.15 0.19 0.23 0.20 0.24 4.73
max 23.22 26.15 27.03 32.58 35.71 35.43 43.86 50.62 53.24 48.30 max 0.21 0.37 0.37 0.34 2.52 31.32
min 0.17 0.46 2.43 4.84 7.86 17.40 15.36 29.37 36.86 40.49 min 0.12 0.11 0.13 0.09 0.12 0.13
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 0.11 0.19 0.18 0.59 2.16 0.17 0.15 0.44 0.30 JAN 0.14 0.10 0.17 0.09 0.15 0.20 JAN 0.10 0.07 0.14 2.29
FEB 0.08 0.19 0.18 0.50 1.71 0.13 0.14 0.42 0.15 FEB 0.11 0.09 0.12 0.08 0.13 0.11 FEB 0.09 0.07 0.10 0.59
MAR 0.09 0.20 0.21 0.71 0.97 0.14 0.15 0.43 0.26 MAR 0.13 0.09 0.13 0.09 0.13 0.16 MAR 0.14 0.10 0.07 0.12 3.03
APR 0.11 0.20 0.21 0.56 1.89 0.25 0.13 0.87 0.29 APR 0.13 0.08 0.12 0.08 0.11 0.16 APR 0.13 0.08 0.07 0.10 0.64
MAY 0.10 0.19 0.17 0.70 2.72 0.16 0.13 0.84 0.30 MAY 0.13 0.09 0.14 0.09 0.12 0.18 MAY 0.13 0.09 0.07 0.15 4.20
JUN 0.18 0.28 0.24 0.86 6.07 0.18 0.26 1.16 0.28 JUN 0.15 0.10 0.44 0.14 0.12 0.23 JUN 0.29 0.12 0.17 15.75
JUL 0.17 0.29 0.26 0.50 10.43 0.33 1.29 0.37 JUL 0.14 0.10 0.43 0.33 0.13 0.19 JUL 4.35 0.14 0.17 22.58
AUG 0.15 0.30 0.34 2.09 5.95 0.29 0.23 0.74 0.19 AUG 0.17 0.12 0.51 0.34 0.10 0.28 AUG 4.81 0.13 0.21 30.10
SEP 0.10 0.24 0.25 0.92 3.99 0.17 0.14 1.15 0.24 SEP 0.15 0.10 0.23 0.35 0.17 0.18 SEP 0.15 0.13 0.10 0.15 1.01
OCT 0.13 0.22 0.23 1.11 2.60 0.17 0.22 0.95 0.23 OCT 0.15 0.10 0.22 0.51 0.15 0.19 OCT 0.19 0.12 0.09 0.14 2.72
NOV 0.12 0.24 0.23 0.92 1.87 0.19 0.16 1.14 0.25 NOV 0.15 0.10 0.32 0.51 0.15 0.21 NOV 0.23 0.15 0.09 0.18 14.40
DEC 0.14 0.29 0.22 0.83 1.47 0.18 0.23 1.14 0.27 DEC 0.15 0.11 0.20 0.21 0.16 0.22 DEC 0.22 0.14 0.10 0.17 11.56
mean 0.12 0.23 0.22 0.86 3.49 0.18 0.19 0.88 0.26 mean 0.14 0.10 0.25 0.24 0.13 0.19 mean 1.06 0.12 0.08 0.15 9.07
std dev 0.03 0.04 0.05 0.43 2.75 0.05 0.07 0.31 0.06 std dev 0.02 0.01 0.14 0.17 0.02 0.04 std dev 1.86 0.02 0.01 0.03 9.81
median 0.12 0.23 0.22 0.77 2.38 0.17 0.15 0.91 0.26 median 0.15 0.10 0.21 0.17 0.13 0.19 median 0.21 0.12 0.07 0.15 3.62
max 0.18 0.30 0.34 2.09 10.43 0.29 0.33 1.29 0.37 max 0.17 0.12 0.51 0.51 0.17 0.28 max 4.81 0.15 0.10 0.21 30.10
min 0.08 0.19 0.17 0.50 0.97 0.13 0.13 0.42 0.15 min 0.11 0.08 0.12 0.08 0.10 0.11 min 0.13 0.08 0.07 0.10 0.59
25
Table 2.4 pH during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 7.6 7.6 7.6 7.8 7.9 8.0 8.1 8.2 8.1 8.0 JAN 6.4 7.1 7.0 6.9 6.9 7.1
FEB 7.3 7.4 7.5 7.7 7.8 8.1 8.2 8.3 8.2 8.0 FEB 6.4 6.7 6.9 6.3 6.5 6.5
MAR 7.4 7.0 7.4 7.4 7.6 7.7 7.8 8.1 8.0 7.8 MAR 7.2 7.2 7.2 6.9 7.0 6.7
APR 6.9 6.9 7.1 7.1 7.5 7.7 7.9 8.0 8.1 8.0 APR 7.0 7.0 7.0 6.8 6.9 6.8
MAY 7.0 7.0 7.0 7.1 7.4 7.6 7.9 8.0 8.0 7.9 MAY 6.8 6.8 6.7 6.6 6.7 6.9
JUN 7.3 7.5 7.6 7.9 8.0 8.1 8.1 8.0 8.1 8.0 JUN 6.9 6.8 7.0 6.7 6.9 7.0
JUL 7.1 7.2 7.1 7.4 7.7 8.0 7.9 8.0 JUL 7.0 6.5 7.0 6.9 6.9 7.1
AUG 7.0 7.1 7.1 7.3 7.5 7.8 7.9 8.0 AUG 6.8 7.0 6.9 6.9 7.0 7.1
SEP 6.7 6.7 6.8 7.0 7.1 7.3 7.7 7.9 SEP 6.8 7.1 6.7 6.7 6.7 6.5
OCT 7.3 7.2 7.4 7.6 7.7 7.9 8.0 8.0 OCT 6.9 7.2 7.2 6.7 6.9 6.6
NOV 7.3 7.3 7.3 7.5 7.6 7.9 7.9 7.9 NOV 6.6 7.2 7.2 7.0 7.0 6.9
DEC 7.1 7.2 7.2 7.3 7.5 7.7 7.9 7.9 DEC 7.2 7.2 7.3 7.1 7.2 7.0
mean 7.2 7.2 7.3 7.4 7.6 7.9 7.9 8.0 8.0 8.0 mean 6.8 7.0 7.0 6.8 6.9 6.9
std dev 0.2 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.1 0.1 std dev 0.3 0.2 0.2 0.2 0.2 0.2
median 7.2 7.2 7.3 7.4 7.6 7.9 7.9 8.0 8.0 8.0 median 6.9 7.1 7.0 6.9 6.9 6.9
max 7.6 7.6 7.6 7.9 8.0 8.1 8.2 8.3 8.2 8.0 max 7.2 7.2 7.3 7.1 7.2 7.1
min 6.7 6.7 6.8 7.0 7.1 7.6 7.3 7.7 7.9 7.8 min 6.4 6.5 6.7 6.3 6.5 6.5
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 6.1 6.8 6.9 6.9 6.7 7.0 7.0 6.8 6.3 JAN 6.2 6.3 6.4 6.5 6.6 6.7 JAN 6.2 3.9 6.9 6.4
FEB 5.1 6.7 6.9 6.8 6.6 7.1 6.9 6.8 6.3 FEB 6.0 5.9 6.2 6.2 6.4 6.4 FEB 5.9 3.9 6.8 6.3
MAR 5.7 7.0 6.9 6.7 6.7 7.4 7.2 7.3 6.8 MAR 6.6 6.6 6.5 6.8 6.8 6.8 MAR 6.6 6.4 4.0 6.8 6.8
APR 6.3 6.9 6.6 6.4 6.9 7.4 7.1 7.6 6.9 APR 6.9 6.6 6.5 6.1 6.8 6.9 APR 6.6 6.2 4.0 6.8 7.0
MAY 6.3 6.9 6.5 6.3 6.8 8.0 7.0 7.8 7.0 MAY 7.1 6.8 6.7 6.2 7.0 7.1 MAY 6.6 6.4 4.0 6.8 6.9
JUN 6.8 7.2 6.6 6.4 6.8 8.3 7.1 7.7 6.9 JUN 7.2 6.8 7.2 6.3 7.0 7.6 JUN 6.8 6.7 6.8 7.1
JUL 6.7 7.3 7.3 6.5 8.7 7.2 7.9 7.0 JUL 7.1 6.8 7.0 6.5 6.7 7.1 JUL 6.9 6.8 6.6 7.1
AUG 6.6 6.7 6.3 6.6 7.1 8.3 7.0 7.6 6.7 AUG 6.8 6.7 7.1 7.2 6.9 7.3 AUG 6.8 6.8 6.8 7.1
SEP 5.7 6.5 6.5 6.6 6.9 7.4 7.1 7.7 6.7 SEP 6.1 6.1 6.2 6.3 6.8 7.0 SEP 6.0 6.0 3.8 6.5 6.9
OCT 6.5 6.7 6.7 6.6 6.8 7.3 6.7 7.7 7.0 OCT 6.8 6.7 6.5 6.1 7.0 7.2 OCT 6.4 6.4 3.9 6.7 6.8
NOV 6.1 6.5 6.4 6.6 6.8 7.3 7.0 7.6 6.7 NOV 6.7 6.6 6.7 6.1 6.9 7.2 NOV 6.7 6.3 4.1 7.5 6.9
DEC 6.4 6.7 6.6 6.6 6.7 7.5 7.1 7.6 6.5 DEC 6.8 6.6 6.5 5.8 6.7 7.0 DEC 6.8 6.3 3.9 6.9 7.2
mean 6.2 6.8 6.7 6.6 7.0 7.5 7.0 7.5 6.7 mean 6.7 6.5 6.6 6.3 6.8 7.0 mean 6.6 6.4 3.9 6.8 6.9
std dev 0.5 0.2 0.3 0.2 0.6 0.5 0.1 0.4 0.3 std dev 0.4 0.3 0.3 0.4 0.2 0.3 std dev 0.3 0.3 0.1 0.2 0.3
median 6.3 6.8 6.6 6.6 6.8 7.4 7.1 7.6 6.8 median 6.8 6.6 6.5 6.3 6.8 7.1 median 6.7 6.4 3.9 6.8 6.9
max 6.8 7.3 7.3 6.9 8.7 8.3 7.2 7.9 7.0 max 7.2 6.8 7.2 7.2 7.0 7.6 max 6.9 6.8 4.1 7.5 7.2
min 5.1 6.5 6.3 6.3 6.6 7.0 6.7 6.8 6.3 min 6.0 5.9 6.2 5.8 6.4 6.4 min 6.0 5.9 3.8 6.5 6.3
26
Table 2.5 Dissolved Oxygen (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 11.4 11.3 11.1 11.0 11.1 11.2 11.3 11.5 10.7 10.6 JAN 13.2 12.9 12.1 12.1 11.9 11.1
FEB 10.8 10.8 10.9 11.1 11.3 11.6 11.9 11.8 11.2 10.2 FEB 12.3 12.0 11.9 10.5 11.0 10.1
MAR 9.2 9.2 9.2 9.2 9.4 9.5 9.8 10.1 10.0 9.0 MAR 10.0 9.7 9.5 9.0 9.2 7.8
APR 6.7 6.9 7.1 7.4 7.4 7.8 7.9 8.0 8.2 7.7 APR 10.1 9.5 9.4 8.8 9.1 8.1
MAY 5.9 6.4 6.0 6.3 6.8 7.0 7.4 7.5 7.3 6.7 MAY 6.9 6.6 5.5 5.4 5.4 6.1
JUN 5.4 5.0 7.0 7.5 8.1 7.7 7.1 6.2 6.4 6.6 JUN 7.3 6.1 5.0 4.7 5.4 5.7
JUL 3.8 4.7 4.0 5.2 6.0 6.9 6.1 6.2 JUL 7.9 5.3 5.1 5.1 4.7 4.4
AUG 3.1 3.3 3.7 3.9 5.0 6.1 5.6 5.5 AUG 7.3 5.1 3.9 3.4 3.2 3.0
SEP 3.7 3.5 3.7 3.2 3.5 4.9 5.8 5.9 SEP 6.1 5.3 3.7 3.8 3.2 1.7
OCT 5.6 5.4 6.0 6.5 6.8 7.1 7.1 7.1 OCT 7.3 6.8 6.6 5.1 5.8 3.4
NOV 7.2 7.3 7.3 7.3 7.5 8.2 8.1 7.8 NOV 8.5 7.8 6.8 6.6 6.5 6.9
DEC 8.7 8.8 8.4 8.1 8.4 8.3 8.5 8.5 DEC 9.7 9.4 9.2 7.8 8.5 7.8
mean 6.8 6.9 7.0 7.2 7.6 9.1 8.1 8.0 7.9 8.5 mean 8.9 8.0 7.4 6.9 7.0 6.3
std dev 2.8 2.7 2.6 2.5 2.3 1.9 2.0 2.1 1.9 1.7 std dev 2.2 2.6 2.9 2.8 2.9 2.9
median 6.3 6.7 7.1 7.4 7.5 8.7 7.7 7.8 7.6 8.4 median 8.2 7.3 6.7 6.0 6.2 6.5
max 11.4 11.3 11.1 11.1 11.3 11.6 11.9 11.8 11.2 10.6 max 13.2 12.9 12.1 12.1 11.9 11.1
min 3.1 3.3 3.7 3.2 3.5 7.0 4.9 5.6 5.5 6.6 min 6.1 5.1 3.7 3.4 3.2 1.7
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 10.6 11.6 10.9 10.0 10.4 11.5 12.3 10.6 8.7 JAN 13.8 13.1 12.7 11.8 13.6 12.5 JAN 11.7 9.9 10.5 10.1
FEB 9.9 8.5 9.4 8.5 10.5 11.3 9.3 9.5 7.8 FEB 10.3 10.4 9.2 9.5 10.7 10.7 FEB 9.5 8.0 8.9 9.2
MAR 10.9 10.6 9.9 8.7 8.4 11.3 10.7 9.0 6.8 MAR 9.9 9.1 7.2 5.5 7.1 7.1 MAR 8.1 8.4 7.1 7.7 8.2
APR 3.1 5.4 1.7 2.4 5.5 6.1 6.4 4.4 0.2 APR 8.4 8.3 6.1 4.4 8.8 7.7 APR 8.1 7.5 6.9 6.9 8.2
MAY 5.0 6.5 3.3 2.4 4.4 10.5 7.3 8.8 0.8 MAY 8.0 7.9 6.4 3.0 7.9 6.7 MAY 4.3 5.2 5.4 2.0 6.1
JUN 2.6 5.8 3.0 3.5 7.4 9.4 5.1 4.8 1.6 JUN 6.5 5.8 6.5 2.5 7.4 9.5 JUN 4.5 4.6 2.5 4.8
JUL 0.6 5.9 6.9 1.6 14.5 *6.0 5.0 0.4 JUL 5.2 5.5 4.0 3.2 5.9 5.1 JUL 5.3 4.3 1.9 4.2
AUG 1.2 5.4 1.0 1.6 1.2 9.5 3.6 4.7 0.8 AUG 5.7 4.8 4.2 8.4 6.2 6.8 AUG 5.5 4.1 1.6 3.2
SEP 3.3 4.0 1.6 1.7 6.5 8.2 5.7 4.7 1.4 SEP 4.1 6.0 2.9 2.9 7.1 5.9 SEP 0.3 3.0 4.4 2.1 3.6
OCT 5.1 7.3 3.1 3.5 7.9 10.5 7.0 7.6 2.6 OCT 8.4 8.6 5.1 0.6 8.8 8.2 OCT 3.2 6.1 6.8 4.3 4.5
NOV 3.5 5.7 2.1 3.7 7.6 7.1 6.9 5.1 0.3 NOV 10.0 10.3 8.8 2.9 9.9 8.8 NOV 5.7 8.1 8.3 6.0 6.9
DEC 7.6 10.1 7.9 6.7 8.0 13.2 9.2 7.7 3.0 DEC 9.4 9.5 7.0 2.2 9.6 8.0 DEC 8.0 10.0 8.6 6.4 8.6
mean 5.3 7.2 5.1 4.5 7.7 9.9 7.5 6.8 2.9 mean 8.3 8.3 6.7 4.7 8.6 8.1 mean 5.3 6.9 7.3 5.1 6.5
std dev 3.6 2.4 3.7 3.1 3.3 2.1 2.5 2.3 3.1 std dev 2.7 2.4 2.7 3.4 2.2 2.1 std dev 2.5 2.7 1.7 3.1 2.4
median 4.3 6.2 3.2 3.5 7.8 10.5 7.0 6.4 1.5 median 8.4 8.5 6.5 3.1 8.4 7.9 median 5.4 6.8 7.1 5.2 6.5
max 10.9 11.6 10.9 10.0 14.5 13.2 12.3 10.6 8.7 max 13.8 13.1 12.7 11.8 13.6 12.5 max 8.1 11.7 9.9 10.5 10.1
min 0.6 4.0 1.0 1.6 1.2 6.1 3.6 4.4 0.2 min 4.1 4.8 2.9 0.6 5.9 5.1 min 0.3 3.0 4.4 1.6 3.2
27
012345678910
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Dissolved Oxygen (mg/L)
Fi
g
u
r
e
2
.
2
D
i
s
s
o
l
v
e
d
O
x
y
g
e
n
a
t
t
h
e
L
o
w
e
r
C
a
pe
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
0
v
e
r
s
u
s
2
0
1
1
.
1995-2010 2011
28
Table 2.6 Field Turbidity (NTU) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 15 16 13 7 8 9 6 5 6 8 JAN 3 4 5 5 7 12
FEB 44 17 10 8 7 7 6 6 7 4 FEB 38 31 27 8 12 6
MAR 17 17 19 12 12 10 9 10 14 8 MAR 27 29 32 18 21 17
APR 17 16 13 9 22 8 8 7 7 17 APR 16 12 10 8 7 6
MAY 14 13 10 7 11 8 5 5 9 8 MAY 8 9 7 7 6 10
JUN 4 7 7 5 5 4 3 4 5 5 JUN 5 5 6 4 5 6
JUL 22 16 18 10 19 14 8 7 JUL 20 7 8 8 15 16
AUG 8 10 9 6 6 6 4 4 AUG 9 5 7 7 3 16
SEP 17 10 11 6 6 6 4 4 SEP 6 8 5 5 5 6
OCT 23 31 15 12 12 8 7 13 OCT 5 8 5 2 5 2
NOV 24 18 13 11 10 8 8 16 NOV 3 6 7 3 3 4
DEC 44 34 24 15 10 6 4 5 DEC 60 61 22 6 9 23
mean 21 17 14 9 11 8 7 6 8 8 mean 17 15 12 7 8 10
std dev 12 8 5 3 5 2 3 2 4 5 std dev 17 17 10 4 5 6
median 17 16 13 9 10 8 6 6 7 8 median 9 8 7 7 7 8
max 44 34 24 15 22 10 14 10 16 17 max 60 61 32 18 21 23
min 4 7 7 5 5 4 3 4 4 4 min 3 4 5 2 3 2
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 6 2 2 2 7 20 3 7 4 JAN 4 3 2 1 3 5 JAN 2 3 11 13
FEB 7 4 3 2 5 4 4 6 6 FEB 11 7 3 2 10 26 FEB 2 2 3 15
MAR 9 5 3 4 10 6 8 12 14 MAR 10 12 5 4 7 7 MAR 4 4 4 5 20
APR 7 5 6 3 13 4 7 10 7 APR 5 5 3 1 5 5 APR 4 4 2 14 26
MAY 12 4 3 2 13 2 5 5 4 MAY 6 6 5 3 6 8 MAY 6 6 2 4 18
JUN 5 2 12 9 44 4 5 12 10 JUN 2 1 5 14 2 5 JUN 4 2 3 10
JUL 3 1 22 15 13 2 6 21 JUL 2 3 2 10 6 19 JUL 4 1 2 7
AUG 3 2 9 15 17 1.0 2 5 5 AUG 3 4 3 10 3 11 AUG 6 1 3 33
SEP 2 2 5 11 9 2 4 6 5 SEP 3 5 10 16 2 3 SEP 4 1 2 1 17
OCT 5 4 4 5 11 2 4 7 11 OCT 3 2 5 45 2 3 OCT 3 4 3 3 8
NOV 4 3 2 3 19 2 3 11 8 NOV 4 3 4 48 6 5 NOV 5 3 2 3 10
DEC 5 4 3 3 19 4 5 8 5 DEC 3 1 2 3 1 2 DEC 5 3 2 5 19
mean 6 3 6 6 15 5 4 8 8 mean 5 4 4 13 4 8 mean 5 3 2 5 16
std dev 3 1 6 5 10 5 2 3 5 std dev 3 3 2 16 3 7 std dev 1 2 1 4 8
median 5 4 4 4 13 4 4 7 7 median 4 4 4 7 4 5 median 4 3 2 3 16
max 12 5 22 15 44 20 8 12 21 max 11 12 10 48 10 26 max 6 6 4 14 33
min 2 1 2 2 5 1 2 5 4 min 2 1 2 1 1 2 min 3 1 2 1 7
29
051015202530
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Field Turbidity (NTU)
Fi
g
u
r
e
2
.
3
F
i
e
l
d
T
u
r
b
i
d
i
t
y
a
t
t
h
e
L
o
w
e
r
C
a
pe
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
0
v
e
r
s
u
s
2
0
1
1
.
1995‐2010 2011
30
Table 2.7 Total Suspended Solids (mg/L) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 20 25 21 15 19 21 19 12 18 21 JAN 4 4 7 6 13
FEB 78 14 13 14 14 15 16 17 23 16 FEB 30 25 23 8 4
MAR 19 23 22 18 17 18 17 24 34 21 MAR 18 24 17 15 17
APR 19 15 14 11 40 14 18 18 24 28 APR 12 15 8 5 7
MAY 16 11 15 8 14 15 12 9 10 20 MAY 7 7 7 5 10
JUN 18 34 19 14 19 18 15 18 17 18 JUN 6 7 15 6 11
JUL 27 23 17 20 29 28 21 20 JUL 15 5 9 23 48
AUG 20 18 25 28 18 25 18 24 AUG 9 8 10 21 37
SEP 31 10 11 8 8 11 14 18 SEP 7 6 7 6 7
OCT 20 14 12 9 11 11 8 14 OCT 6 8 10 5 5
NOV 21 13 15 12 14 13 10 12 NOV 4 3 10 6 8
DEC 24 16 14 12 10 7 9 12 DEC 56 62 19 6 23
mean 26 18 16 14 18 17 16 15 19 21 mean 14 14 12 9 16
std dev 17 7 4 6 9 3 6 5 7 4 std dev 15 17 5 6 14
median 20 15 15 13 16 16 16 15 18 20 median 8 8 10 6 10
max 78 34 25 28 40 21 28 24 34 28 max 56 62 23 23 48
min 16 10 11 8 8 14 7 8 10 16 min 4 3 7 5 4
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 2 3 2 2 6 17 2 5 3 JAN 2 2 2 2 2 2 JAN 2 2 2
FEB 2 3 2 2 9 2 3 3 8 FEB 9 6 3 2 12 32 FEB 2 2 2
MAR 3 3 2 2 28 5 2 6 6 MAR 7 10 4 2 3 2 MAR 2 2 2 3
APR 7 8 12 2 17 2 4 10 10 APR 6 7 4 5 6 4 APR 3 3 2 4
MAY 7 5 5 2 14 9 3 4 6 MAY 3 3 3 3 2 2 MAY 4 5 2 5
JUN 37 2 157 12 45 3 2 12 6 JUN 2 2 55 19 4 3 JUN 7 2 2
JUL 16 4 16 14 27 3 5 20 JUL 2 2 4 15 5 21 JUL 4 2 3
AUG 5 2 21 6 25 2 2 12 9 AUG 2 2 3 9 2 7 AUG 7 2 2
SEP 5 3 6 2 4 8 9 SEP 23 SEP 10 2 2
OCT 2 2 5 2 2 4 4 OCT 6 OCT 4 2 2
NOV 2 2 11 2 2 4 5 NOV 3 NOV 5 2 2
DEC 1 1 10 1 1 4 17 DEC 2 DEC 4 2 1
mean 10 3 27 4 17 4 2 6 8 mean 4 4 9 7 4 9 mean 5 2 2 3
std dev 12 2 53 4 12 5 1 3 5 std dev 3 3 15 7 3 11 std dev 2 1 0 1
median 6 3 8 2 12 2 2 5 7 median 2 2 3 4 4 3 median 4 2 2 2
max 37 8 157 14 45 17 4 12 20 max 9 10 55 19 12 32 max 10 5 2 5
min 2 1 2 1 5 1 1 3 3 min 2 2 2 2 2 2 min 2 2 2 1
31
Table 2.8 Light Attenuation (k) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 3.13 3.04 3.00 2.21 2.35 2.11 1.84 1.87 1.11 1.56 JAN 1.48 1.61 1.99 1.80 2.54 3.87
FEB 5.99 3.58 3.68 5.07 2.32 2.22 2.16 1.57 1.60 1.33 FEB 3.41 3.78 3.06 3.13 3.06 3.39
MAR 3.61 3.79 3.85 3.57 3.13 2.92 2.58 2.31 2.42 1.82 MAR 2.43 2.57 3.52 2.62 2.70 4.90
APR 3.63 3.90 3.09 2.63 4.12 2.11 1.62 1.31 1.18 2.23 APR 2.43 2.58 2.09 2.44 2.24 3.72
MAY 3.76 3.2 3.11 2.56 3.1 1.95 1.75 1.32 1.54 1.66 MAY 2.10 2.06 3.14 3.40 3.32 3.67
JUN 3.20 2.49 2.33 1.96 2.15 1.62 1.19 1.04 0.81 1.22 JUN 1.73 1.65 2.65 2.44 2.29 2.79
JUL 2.72 1.73 2.89 2.06 1.27 1.05 JUL 2.89 1.80 2.35 2.48 2.41 3.29
AUG 2.27 2.32 2.13 2.10 1.79 1.19 1.28 1.15 AUG 2.07 2.21 2.25 2.32 2.94 2.69
SEP 4.56 4.36 4.31 4.32 3.47 2.87 2.02 1.88 SEP 1.88 2.25 3.12 2.71 2.96 4.32
OCT 3.43 3.30 2.49 2.28 1.77 1.30 1.27 OCT 1.85 2.55 2.05 3.39 2.24 5.27
NOV 3.39 2.99 2.79 2.12 2.16 1.63 1.27 1.60 NOV 1.55 1.95 2.75 2.85 2.88 3.84
DEC 5.16 4.18 3.76 2.74 2.02 1.76 1.36 1.31 DEC 5.56 5.57 2.70 2.64 2.48 5.60
mean 3.83 3.38 3.16 2.79 2.65 2.16 1.87 1.49 1.41 1.64 mean 2.45 2.55 2.64 2.69 2.67 3.95
std dev 1.04 0.66 0.67 1.02 0.70 0.43 0.50 0.38 0.43 0.36 std dev 1.13 1.12 0.50 0.46 0.36 0.92
max 5.99 4.36 4.31 5.07 4.12 2.92 2.87 2.31 2.42 2.23 max 5.56 5.57 3.52 3.40 3.32 5.60
min 2.27 2.32 2.13 1.73 1.79 1.62 1.19 1.04 0.81 1.22 min 1.48 1.61 1.99 1.80 2.24 2.69
32
Table 2.9 Total Nitrogen (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 940 720 740 600 540 460 350 210 120 150 JAN 1,410 1,420 1,070 1,130 560
FEB 1,930 1,610 1,330 1,000 970 890 650 150 110 110 FEB 1,750 1,700 1,700 1,230 1,040
MAR 1,420 1,750 990 1,370 1,000 990 770 740 580 720 MAR 1,740 2,300 1,280 1,580 890
APR 640 640 660 620 670 660 760 540 630 620 APR 1,370 1,080 1,310 1,120 810
MAY 1,240 1,020 930 750 850 680 520 540 240 470 MAY 1,650 1,460 1,280 1,160 790
JUN 920 870 790 640 620 430 410 410 310 310 JUN 1,030 1,040 1,250 1,210 800
JUL 930 780 750 750 730 510 310 310 JUL 1,180 1,350 1,360 1,530 1,010
AUG 710 860 1,080 1,270 930 690 420 510 AUG 1,390 1,300 1,540 1,160 990
SEP 1,070 950 940 930 870 760 560 290 SEP 1,170 1,250 1,210 980 1,230
OCT 1,270 1,420 1,340 1,010 1,120 920 640 310 OCT 920 1,100 1,400 1,140 990
NOV 1,400 1,290 1,200 1,040 880 680 360 250 NOV 2,160 2,140 2,310 2,030 920
DEC 950 1,100 780 760 810 640 1,130 350 DEC 1,300 970 1,100 860 560
mean 1,118 1,084 961 895 833 685 638 501 334 397 mean 1,423 1,426 1,401 1,261 883
std dev 342 343 223 242 161 205 157 251 157 227 std dev 336 407 321 300 186
median 1,010 985 935 845 860 670 665 480 310 390 median 1,380 1,325 1,295 1,160 905
max 1,930 1,750 1,340 1,370 1,120 990 920 1,130 630 720 max 2,160 2,300 2,310 2,030 1,230
min 640 640 660 600 540 430 350 150 110 110 min 920 970 1,070 860 560
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 1,390 1,520 510 2,120 1,360 1,330 1,360 5,820 1,150 JAN 1,830 1,070 550 230 550 290 JAN 1,250 930 2,730
FEB 1,270 1,570 810 1,700 1,920 1,250 1,810 6,050 590 FEB 2,050 1,610 780 470 1,460 1,880 FEB 1,240 1,010 660
MAR 1,100 890 510 810 1,670 570 920 5,140 1,570 MAR 2,050 1,720 1,250 1,250 1,090 1,080 MAR 950 630 710 580
APR 2,350 1,500 1,140 950 1,550 640 1,180 24,200 1,340 APR 810 380 400 230 270 430 APR 1,210 730 630 430
MAY 920 820 630 610 1,180 440 840 18,250 730 MAY 1,010 720 720 620 560 520 MAY 1,030 870 850 1,460
JUN 1,240 2,210 950 950 2,250 410 5,540 27,950 850 JUN 670 1,170 4,070 2,010 660 480 JUN 1,500 1,150 1,570
JUL 710 840 1,520 1,010 3,510 610 31,650 2,240 JUL 550 1,040 1,730 1,010 880 720 JUL 640 590 2,230
AUG 810 2,400 2,380 910 7,230 210 2,660 17,100 1,070 AUG 2,010 760 940 1,320 330 320 AUG 630 460 4,020
SEP 1,540 1,290 1,030 800 2,190 690 1,480 28,150 1,130 SEP 810 890 1,740 910 570 430 SEP 1,250 970 760 1,280
OCT 1,050 1,020 710 540 760 440 3,140 26,050 570 OCT 1,410 900 1,260 1,650 700 360 OCT 1,040 1,000 950 560
NOV 820 550 510 570 830 210 830 25,450 350 NOV 1,430 1,100 1,800 1,140 950 420 NOV 1,120 720 720 1,240
DEC 840 700 510 700 1,060 820 2,600 27,850 690 DEC 750 210 250 610 230 70 DEC 680 600 510 610
mean 1,170 1,276 934 973 2,126 637 1,914 20,305 1,023 mean 1,282 964 1,291 954 688 583 mean 1,005 851 786 1,448
std dev 433 563 529 453 1,701 356 1,346 9,299 499 std dev 560 417 980 530 345 457 std dev 273 258 154 1,035
median 1,075 1,155 760 860 1,610 570 1,420 24,825 960 median 1,210 970 1,095 960 615 430 median 1,035 800 760 1,260
max 2,350 2,400 2,380 2,120 7,230 1,330 5,540 31,650 2,240 max 2,050 1,720 4,070 2,010 1,460 1,880 max 1,500 1,250 1,010 4,020
min 710 550 510 540 760 210 610 5,140 350 min 550 210 250 230 230 70 min 630 460 510 430
33
0
20
0
40
0
60
0
80
0
1,
0
0
0
1,
2
0
0
1,
4
0
0
1,
6
0
0
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
Total Nitrogen (g/L)
Fi
g
u
r
e
2
.
4
T
o
t
a
l
N
i
t
r
o
g
e
n
a
t
t
h
e
L
o
w
e
r
C
a
p
e
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
0
v
e
r
s
u
s
2
0
1
1
.
1995-2010 2011
34
Table 2.10 Nitrate/Nitrite (mg/l) during 2011 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 840 620 640 500 440 360 250 110 20 50 JAN 1310 1320 970 1030 460
FEB 730 510 530 400 370 290 250 50 10 10 FEB 1150 1100 1100 730 340
MAR 520 450 390 370 300 290 270 140 80 20 MAR 840 800 780 780 290
APR 540 540 560 520 470 360 260 140 30 120 APR 770 680 810 720 210
MAY 440 420 430 350 350 280 220 140 40 70 MAY 850 860 680 560 290
JUN 520 270 290 240 120 30 10 10 10 10 JUN 730 740 850 910 400
JUL 430 380 350 250 130 10 10 10 JUL 380 850 760 930 410
AUG 610 560 480 470 330 90 20 10 AUG 690 600 540 460 390
SEP 470 450 340 230 270 260 160 90 SEP 870 850 610 480 130
OCT 570 520 540 410 420 220 140 10 OCT 620 600 900 740 190
NOV 800 690 700 540 480 280 160 50 NOV 1560 1440 1510 1330 320
DEC 750 800 480 560 610 590 430 300 DEC 900 920 1050 810 260
mean 602 518 478 403 358 268 226 126 55 47 mean 889 897 880 790 308
std dev 137 136 119 114 136 112 145 108 79 39 std dev 304 255 249 233 95
median 555 515 480 405 360 290 250 140 25 35 median 845 850 830 760 305
max 840 800 700 560 610 360 590 430 300 120 max 1,560 1,440 1,510 1,330 460
min 430 270 290 230 120 30 10 10 10 10 min 380 600 540 460 130
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 290 720 10 1320 260 430 760 5020 350 JAN 1730 970 450 130 450 190 JAN 350 30 230
FEB 70 570 10 800 1020 450 1010 4950 90 FEB 1350 1010 380 170 960 1080 FEB 440 10 60
MAR 200 390 10 410 670 70 420 4640 270 MAR 1150 620 150 150 290 180 MAR 250 230 10 80
APR 150 600 40 250 50 40 380 24100 240 APR 710 280 200 130 170 130 APR 610 230 30 30
MAY 120 320 30 210 180 40 440 18200 30 MAY 510 320 220 120 260 120 MAY 430 270 50 360
JUN 40 1510 50 50 50 10 4940 27900 50 JUN 70 170 2970 10 360 80 JUN 300 250 670
JUL 10 40 20 10 210 10 31600 40 JUL 150 240 930 10 480 120 JUL 240 90 1230
AUG 10 1100 80 10 30 10 1260 16700 270 AUG 1410 160 140 20 230 20 AUG 130 60 920
SEP 40 90 30 100 890 90 380 28100 130 SEP 110 90 40 10 170 30 SEP 50 70 60 180
OCT 50 220 10 40 60 40 1640 26000 170 OCT 710 200 60 50 300 60 OCT 340 200 50 160
NOV 20 150 10 170 30 10 230 25400 150 NOV 830 300 1000 40 250 20 NOV 220 220 20 440
DEC 40 200 10 300 60 20 1100 27800 190 DEC 700 160 150 110 180 20 DEC 180 200 10 210
mean 87 493 26 306 293 110 1,048 20,034 165 mean 786 377 558 79 342 171 mean 275 218 30 381
std dev 83 424 21 373 343 157 1,259 9,602 99 std dev 517 303 789 59 210 280 std dev 151 106 18 360
median 45 355 15 190 120 40 600 24,750 160 median 710 260 210 80 275 100 median 245 225 30 220
max 290 1,510 80 1,320 1,020 450 4,940 31,600 350 max 1,730 1,010 2,970 170 960 1,080 max 610 440 60 1,230
min 10 40 10 10 30 10 10 4,640 30 min 70 90 40 10 170 20 min 50 60 10 30
35
Table 2.11 Ammonium (mg/l) during 2011 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 50 60 70 60 70 40 10 10 5 5 JAN 30 10 20 40 70
FEB 40 50 40 40 20 40 5 5 5 5 FEB 20 10 60 40 10
MAR 90 80 80 80 60 70 60 10 10 5 MAR 80 120 40 70 40
APR 60 60 10 70 80 50 10 10 5 10 APR 30 40 80 60 30
MAY 90 100 110 80 100 50 30 10 10 10 MAY 120 70 80 50 30
JUN 50 80 5 5 5 5 5 5 5 5 JUN 60 100 130 30 20
JUL 20 5 10 5 10 5 10 5 JUL 20 90 50 30 5
AUG 5 10 5 10 10 5 5 5 AUG 100 190 60 50 10
SEP 30 40 60 80 70 30 10 10 SEP 50 160 70 60 150
OCT 40 5 10 10 40 10 20 10 OCT 60 170 90 70 30
NOV 90 90 100 90 100 40 20 10 NOV 30 100 120 50 10
DEC 70 80 90 100 110 100 60 50 DEC 70 110 110 90 20
mean 53 55 49 53 56 43 26 15 11 7 mean 56 98 76 53 35
std dev 28 34 40 36 38 21 29 15 13 3 std dev 32 59 33 18 40
median 50 60 50 65 65 45 10 10 8 5 median 55 100 75 50 25
max 90 100 110 100 110 70 100 60 50 10 max 120 190 130 90 150
min 5 5 5 5 5 5 5 5 5 5 min 20 10 20 30 5
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 5 5 10 40 170 150 20 50 110 JAN 40 40 10 10 10 10 JAN 20 10 1,360
FEB 10 30 20 20 80 10 60 50 60 FEB 50 30 40 5 5 5 FEB 5 10 100
MAR 120 10 10 10 150 10 10 150 170 MAR 20 10 10 10 10 20 MAR 40 10 20 100
APR 2,320 140 160 130 320 30 40 110 300 APR 20 50 20 20 20 50 APR 40 20 20 110
MAY 180 50 70 100 460 20 80 100 460 MAY 50 50 60 20 50 90 MAY 130 100 110 960
JUN 130 60 40 250 1,570 10 70 110 230 JUN 20 30 40 50 40 40 JUN 10 40 90
JUL 10 30 180 300 60 20 90 550 JUL 50 30 90 70 70 140 JUL 5 10 5
AUG 5 40 50 150 4,670 10 40 30 280 AUG 50 30 50 20 30 20 AUG 20 30 80 2,950
SEP 180 130 10 70 560 90 50 70 360 SEP 40 10 70 50 30 20 SEP 100 10 80 610
OCT 50 20 40 120 210 10 910 60 90 OCT 40 5 40 320 30 20 OCT 100 10 40 80
NOV 20 40 20 60 220 10 10 50 20 NOV 20 5 30 10 5 5 NOV 20 20 10 330
DEC 20 10 10 30 180 5 900 70 30 DEC 40 10 20 20 20 10 DEC 20 10 5 180
mean 254 47 52 107 721 32 184 78 222 mean 37 25 40 50 27 36 mean 49 24 39 573
std dev 654 44 59 91 1,309 46 337 34 173 std dev 13 17 24 87 20 41 std dev 45 26 38 858
median 35 35 30 85 215 10 45 70 200 median 40 30 40 20 25 20 median 30 15 20 145
max 2,320 140 180 300 4,670 150 910 150 550 max 50 50 90 320 70 140 max 130 100 110 2,950
min 5 5 10 10 60 5 10 30 20 min 20 5 10 5 5 5 min 5 5 5 5
36
Table 2.12 Total Kjeldahl Nitrogen (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 100 100 100 100 100 100 100 100 100 100 JAN 100 100 100 100 100
FEB 1200 1100 800 600 600 600 400 100 100 100 FEB 600 600 600 500 700
MAR 900 1300 600 1000 700 700 500 600 500 700 MAR 900 1500 500 800 600
APR 100 100 100 100 200 300 500 400 600 500 APR 600 400 500 400 600
MAY 800 600 500 400 500 400 300 400 200 400 MAY 800 600 600 600 500
JUN 400 600 500 400 500 400 400 400 300 300 JUN 300 300 400 300 400
JUL 500 400 400 500 600 500 300 300 JUL 800 500 600 600 600
AUG 100 300 600 800 600 600 400 500 AUG 700 700 1000 700 600
SEP 600 500 600 700 600 500 400 200 SEP 300 400 600 500 1,100
OCT 700 900 800 600 700 700 500 300 OCT 300 500 500 400 800
NOV 600 600 500 500 400 400 200 200 NOV 600 700 800 700 600
DEC 200 300 300 200 200 50 700 50 DEC 400 50 50 50 300
mean 517 567 483 492 475 417 413 375 279 350 mean 533 529 521 471 575
std dev 339 359 219 263 196 195 180 174 168 214 std dev 239 355 250 224 238
median 550 550 500 500 550 400 450 400 250 350 median 600 500 550 500 600
max 1,200 1,300 800 1,000 700 700 700 700 600 700 max 900 1,500 1,000 800 1,100
min 100 100 100 100 100 100 50 100 50 100 min 100 50 50 50 100
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 1100 800 500 800 1100 900 600 800 800 JAN 100 100 100 100 100 100 JAN 900 900 2500
FEB 1200 1000 800 900 900 800 800 1100 500 FEB 700 600 400 300 500 800 FEB 800 1000 600
MAR 900 500 500 400 1000 500 500 500 1300 MAR 900 1100 1100 1100 800 900 MAR 700 400 700 500
APR 2200 900 1100 700 1500 600 800 100 1100 APR 100 100 200 100 100 300 APR 600 500 600 400
MAY 800 500 600 400 1000 400 400 50 700 MAY 500 400 500 500 300 400 MAY 600 600 800 1100
JUN 1200 700 900 900 2200 400 600 50 800 JUN 600 1000 1100 2000 300 400 JUN 1200 900 900
JUL 700 800 1500 1000 3300 600 50 2200 JUL 400 800 800 1000 400 600 JUL 400 500 1000
AUG 800 1300 2300 900 7200 200 1400 400 800 AUG 600 600 800 1300 100 300 AUG 500 400 3100
SEP 1500 1200 1000 700 1300 600 1100 50 1000 SEP 700 800 1700 900 400 400 SEP 1200 900 700 1100
OCT 1000 800 700 500 700 400 1500 50 400 OCT 700 700 1200 1600 400 300 OCT 700 800 900 400
NOV 800 400 500 400 800 200 600 50 200 NOV 600 800 800 1100 700 400 NOV 900 500 700 800
DEC 800 500 500 400 1000 800 1500 50 500 DEC 50 50 100 500 50 50 DEC 500 400 500 400
mean 1,083 783 908 667 1,833 527 867 271 858 mean 496 588 733 875 346 413 mean 730 633 756 1,067
std dev 404 273 512 225 1,764 226 386 342 501 std dev 265 339 473 570 230 240 std dev 269 201 150 825
median 950 800 750 700 1,050 500 700 50 800 median 600 650 800 950 350 400 median 650 550 700 850
max 2,200 1,300 2,300 1,000 7,200 900 1,500 1,100 2,200 max 900 1,100 1,700 2,000 800 900 max 1,200 900 1,000 3,100
min 700 400 500 400 700 200 400 50 200 min 50 50 100 100 50 50 min 400 400 500 400
37
Table 2.13 Total Phosphorus (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 100 90 90 100 70 50 50 60 40 60 JAN 150 140 140 160 50
FEB 210 110 130 90 80 70 90 80 50 40 FEB 210 200 220 140 90
MAR 110 90 60 60 50 50 40 10 30 20 MAR 80 220 110 120 100
APR 110 90 90 80 80 50 60 40 30 40 APR 110 90 80 90 60
MAY 90 120 110 90 100 60 30 10 10 10 MAY 130 110 110 120 70
JUN 80 70 90 80 40 10 20 10 10 10 JUN 140 140 210 160 70
JUL 140 110 120 90 120 50 20 10 JUL 160 160 160 190 80
AUG 70 90 100 90 60 50 50 10 AUG 220 170 230 200 120
SEP 180 150 160 120 100 90 60 30 SEP 100 200 150 140 150
OCT 100 120 100 80 90 60 20 40 OCT 120 140 160 140 130
NOV 160 100 80 80 80 110 10 30 NOV 200 210 380 140 110
DEC 160 150 80 80 120 50 50 50 10 DEC 230 320 190 110 150
mean 126 108 101 87 83 49 58 35 25 30 mean 154 175 178 143 143
std dev 42 23 25 14 24 17 25 24 14 18 std dev 48 58 75 30 30
median 110 105 95 85 80 50 50 30 30 30 median 145 165 160 140 95
max 210 150 160 120 120 70 110 80 50 60 max 230 320 380 200 200
min 70 70 60 60 40 10 20 10 10 10 min 80 90 80 90 90
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 100 70 70 100 200 100 140 430 40 JAN 50 30 70 10 60 60 JAN 70 10 40
FEB 90 140 60 170 180 30 290 520 90 FEB 120 100 110 50 90 140 FEB 80 100 90
MAR 100 80 50 120 410 40 170 820 410 MAR 70 40 140 130 90 60 MAR 120 80 10 10
APR 200 180 220 250 610 90 260 2,950 260 APR 170 50 240 40 100 180 APR 50 40 10 10
MAY 140 130 110 150 350 60 200 2,380 230 MAY 100 50 320 50 70 190 MAY 160 120 10 30
JUN 160 280 300 450 410 40 610 5,080 190 JUN 120 120 670 130 80 160 JUN 100 130 50
JUL 110 490 260 400 380 820 4,770 270 JUL 210 80 760 110 70 350 JUL 40 100 40
AUG 90 160 640 420 2,430 30 1,440 2,590 340 AUG 100 130 1,090 150 80 260 AUG 30 120 30
SEP 170 200 170 270 240 40 700 4,630 360 SEP 170 80 1,650 110 110 280 SEP 310 100 120 10
OCT 120 70 60 140 200 60 810 4,320 240 OCT 190 40 620 140 100 140 OCT 110 140 40 10
NOV 100 70 50 120 170 30 290 3,150 320 NOV 160 50 340 100 70 240 NOV 110 130 10 10
DEC 40 10 40 30 190 10 220 3,080 150 DEC 130 50 250 130 50 170 DEC 50 30 10 10
mean 118 157 169 218 481 48 496 2,893 242 mean 133 68 522 96 81 186 mean 108 95 36 28
std dev 41 122 166 133 601 26 375 1,576 106 std dev 47 32 450 44 17 82 std dev 78 34 41 23
median 105 135 90 160 295 40 290 3,015 250 median 125 50 330 110 80 175 median 105 100 10 20
max 200 490 640 450 2,430 100 1,440 5,080 410 max 210 130 1,650 150 110 350 max 310 140 120 90
min 40 10 40 30 170 10 140 430 40 min 50 30 70 10 50 60 min 30 30 10 10
38
020406080
10
0
12
0
14
0
16
0
18
0
20
0
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
Total Phosphorus (g/L)
Fi
g
u
r
e
2
.
5
T
o
t
a
l
P
h
o
s
p
h
o
r
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L
o
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a
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a
m
m
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s
t
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m
s
t
a
t
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s
,
19
9
5
-
2
0
1
0
v
e
r
s
u
s
2
0
1
1
.
1995-2010 2011
39
Table 2.14 Orthophosphate (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 30 30 30 20 20 10 0 10 0 0 JAN 60 80 80 60 70 10
FEB 70 30 30 20 20 10 0 10 0 0 FEB 70 60 80 50 30 10
MAR 40 30 20 20 20 20 20 0 10 10 MAR 30 60 80 30 50 30
APR 50 50 50 40 30 30 20 10 10 10 APR 50 50 50 30 50 30
MAY 50 60 50 30 20 40 30 20 10 10 MAY 80 80 60 50 60 40
JUN 30 30 30 30 20 10 10 0 10 10 JUN 70 80 120 70 90 40
JUL 60 50 50 50 50 20 20 10 JUL 90 100 90 80 110 50
AUG 60 70 60 70 50 40 30 20 AUG 110 120 120 110 100 60
SEP 70 80 90 80 80 60 40 30 SEP 100 120 100 90 90 70
OCT 50 50 50 50 50 30 20 20 OCT 90 110 120 60 100 70
NOV 70 70 60 60 50 40 20 20 NOV 150 160 190 80 150 40
DEC 60 60 60 50 40 50 50 40 40 DEC 100 100 110 60 90 40
mean 53 51 48 43 38 24 27 18 15 7 mean 83 93 100 64 83 41
std dev 14 18 19 20 19 16 19 13 12 5 std dev 31 31 37 24 33 20
median 55 50 50 45 35 20 25 20 10 10 median 85 90 95 60 90 40
max 70 80 90 80 80 50 60 40 40 10 max 150 160 190 110 150 70
min 30 30 20 20 20 10 0 0 0 0 min 30 50 50 30 30 10
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 30 10 0 20 60 30 50 260 10 JAN 10 10 30 0 10 20 JAN 0 10 0
FEB 60 50 20 40 40 0 80 320 0 FEB 30 10 40 30 10 50 FEB 30 10 0
MAR 60 30 20 40 80 10 170 610 30 MAR 20 10 90 10 30 30 MAR 30 20 10 0
APR 110 50 50 160 70 10 140 2,380 40 APR 40 10 190 10 20 50 APR 20 20 10 0
MAY 80 30 30 70 70 20 90 1,930 30 MAY 40 30 150 10 30 50 MAY 80 40 20 10
JUN 20 40 30 70 40 10 440 3,100 20 JUN 50 40 580 10 30 40 JUN 50 40 20
JUL 20 30 40 90 40 590 3,750 70 JUL 80 50 540 10 30 80 JUL 20 50 20
AUG 10 60 50 80 490 20 780 2,020 130 AUG 50 50 760 10 30 40 AUG 10 50 10
SEP 120 60 40 110 70 10 160 2,760 80 SEP 60 40 480 10 30 90 SEP 130 60 100 10
OCT 70 50 20 70 70 10 450 2,710 100 OCT 60 20 360 10 40 70 OCT 70 60 40 10
NOV 60 20 20 60 60 20 180 2,140 100 NOV 30 20 220 10 20 70 NOV 30 50 10 10
DEC 40 20 20 30 70 10 170 2,590 70 DEC 20 10 170 20 20 70 DEC 40 20 0 10
mean 57 38 28 70 97 14 275 2,048 57 mean 41 25 301 12 25 55 mean 48 37 23 8
std dev 35 17 15 38 125 8 233 1,113 41 std dev 20 16 239 7 9 21 std dev 36 19 31 7
median 60 35 25 70 70 10 170 2,260 55 median 40 20 205 10 30 50 median 35 40 10 10
max 120 60 50 160 490 30 780 3,750 130 max 80 50 760 30 40 90 max 130 60 100 20
min 10 10 0 20 40 0 50 260 0 min 10 10 30 0 10 20 min 10 0 0 0
40
Table 2.15 Chlorophyll a (mg/l) during 2011 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP BBT IC NCF6
JAN 7 9 8 10 11 13 13 17 14 15 JAN 10 14 9 9 8 3
FEB 14 9 9 15 18 18 21 21 16 10 FEB 8 8 7 4 5 3
MAR 7 5 4 3 4 3 3 8 12 7 MAR 7 7 7 5 6 2
APR 3 4 4 4 5 6 8 7 8 6 APR 4 4 3 2 2 2
MAY 5 3 4 3 6 8 7 8 5 5 MAY 1 1 1 0 1 2
JUN 9 8 23 6 7 6 15 7 7 7 JUN 18 8 12 9 11 18
JUL 15 29 16 19 38 25 8 8 JUL 13 5 6 4 3 5
AUG 5 8 10 10 18 21 7 7 AUG 22 8 9 9 13 10
SEP 2 3 7 4 4 8 9 7 SEP 4 5 2 2 2 2
OCT 4 10 6 3 3 3 3 5 OCT 2 2 3 1 2 1
NOV 3 3 3 3 4 6 3 3 NOV 2 1 1 1 1 4
DEC 2 2 2 2 2 2 6 6 DEC 2 2 1 1 1 3
mean 6 8 8 7 10 9 11 9 8 8 mean 8 5 5 4 5 5
std dev 4 7 6 5 10 5 8 5 4 3 std dev 7 4 4 3 4 5
median 5 7 7 4 6 7 8 8 7 7 median 6 5 5 3 3 3
max 15 29 23 19 38 18 25 21 16 15 max 22 14 12 9 13 18
min 2 2 2 2 2 3 2 3 3 5 min 1 1 1 0 1 1
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 3 11 7 11 9 13 4 6 2 JAN 4 1 3 2 9 3 JAN 5 2 2
FEB 2 3 2 5 9 6 1 2 1 FEB 5 3 5 9 5 9 FEB 4 2 1
MAR 5 1 1 2 3 3 1 2 0 MAR 1 1 1 2 1 1 MAR 0 1 4 1
APR 10 1 4 1 39 1 1 1 1 APR 1 1 2 3 1 1 APR 1 2 2 1
MAY 6 1 2 1 6 1 0 0 1 MAY 0 0 1 1 0 0 MAY 1 1 1 13
JUN 74 1 11 5 20 1 0 2 18 JUN 1 0 3 12 0 1 JUN 1 0 1
JUL 25 30 28 50 67 1 1 36 JUL 1 0 1 46 1 7 JUL 5 3 8
AUG 15 2 4 5 29 1 3 2 34 AUG 1 1 2 34 1 23 AUG 9 4 9
SEP 5 4 14 5 4 1 1 1 25 SEP 1 1 3 83 0 6 SEP 1 1 1 1
OCT 2 1 2 2 2 1 1 1 6 OCT 1 0 2 15 1 1 OCT 1 1 1 1
NOV 2 1 1 3 34 1 1 2 7 NOV 1 0 2 91 1 1 NOV 1 0 0 1
DEC 2 1 1 3 3 2 1 1 1 DEC 1 1 2 11 1 2 DEC 1 0 1 1
mean 13 5 6 8 19 3 1 2 11 mean 2 1 2 26 2 5 mean 2 2 2 3
std dev 20 8 8 13 19 4 1 1 13 std dev 1 1 1 30 3 6 std dev 3 2 1 4
median 5 1 3 4 9 1 1 2 4 median 1 1 2 12 1 2 median 1 1 1 1
max 74 30 28 50 67 13 4 6 36 max 5 3 5 91 9 23 max 9 5 4 13
min 2 1 1 1 2 1 0 0 0 min 0 0 1 1 0 0 min 0 0 0 1
41
024681012
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Chlorophyll a(g/L)
Fi
g
u
r
e
2
.
6
C
h
l
o
r
o
p
h
y
l
l
a
at
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,
1
9
9
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-
20
1
0
v
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s
2
0
1
1
.
1995-2010 2011
42
Ta
b
l
e
2
.
1
6
B
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(
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)
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NC
1
1
A
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1
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8
7
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0
8
.
1
4
.
6
9
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2
min
1.
9
3
.
0
1
.
6
1
.
9
2
.
9
2
.
5
Table 2.17 Fecal Coliform/Enterococcus (cfu/100 ml) during 2011 at the Lower Cape Fear River Program stations. Enterococcus analysis at saltwater stations began in September, in italics.
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NC11 AC DP IC NCF6
JAN 19 37 5 10 10 5 5 5 5 5 JAN 5 5 19 28 5
FEB 5 5 5 5 10 10 5 5 5 5 FEB 28 28 10 55 91
MAR 55 46 46 19 55 28 5 10 5 10 MAR 19 1 19 64 55
APR 127 118 91 73 19 5 127 19 10 10 APR 28 10 10 37 5
MAY 10 28 37 10 10 10 5 5 5 5 MAY 5 19 19 28 154
JUN 5 19 5 5 10 10 5 5 5 5 JUN 37 19 390 10 240
JUL 290 118 109 37 37 5 5 5 JUL 37 37 136 5 181
AUG 46 5 46 10 5 5 5 10 AUG 15 29 80 37 22
SEP 46 28 55 46 19 10 5 10 SEP 5 28 19 10 10
OCT 181 181 82 55 46 10 5 10 OCT 5 10 19 37 10
NOV 37 5 37 5 5 5 5 5 NOV 10 590 46 37 10
DEC 118 46 10 10 46 10 10 5 DEC 118 64 37 55 154
mean 78 53 44 24 23 11 16 7 7 7 mean 26 70 67 34 78
std dev 83 54 34 22 17 8 33 4 2 2 std dev 30 158 104 18 80
max 290 181 109 73 55 28 127 19 10 10 max 118 590 390 64 240
min 5 5 5 5 5 5 5 5 5 5 min 5 1 10 5 5
Geomean 40 29 27 15 16 9 8 6 6 6 Geomean 16 21 33 27 34
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 55 82 46 5 82 546 91 220 310 JAN 230 82 19 10 145 270 JAN 82 37 55 73
FEB 28 28 19 73 64 28 64 163 220 FEB 240 220 136 28 46 163 FEB 19 19 64 73
MAR 109 210 19 28 390 455 118 28 100 MAR 181 290 73 64 127 154 MAR 46 64 55 46 64
APR 46 82 118 64 220 546 136 300 10 APR 28 55 46 46 109 154 APR 5 100 37 37 100
MAY 73 46 73 73 60000 230 163 55 82 MAY 100 82 19 136 199 410 MAY 46 64 64 91 64
JUN 273 109 273 273 819 273 127 819 637 JUN 91 37 46 82 546 1091 JUN 55 28 10 37
JUL 210 2100 728 3900 1360 127 546 819 JUL 220 127 91 280 2700 2500 JUL 190 570 580 5300
AUG 136 136 1640 28 60000 190 280 570 9000 AUG 127 82 240 73 1000 55 AUG 82 109 118 55
SEP 109 127 63 36 1000 63 270 136 27 SEP 330 135 490 550 260 406 SEP 199 118 37 390 728
OCT 118 199 37 37 1000 37 154 250 28 OCT 81 81 54 136 118 350 OCT 19 82 73 55 230
NOV 145 136 19 91 530 28 28 240 5 NOV 100 91 230 460 310 3900 NOV 28 91 100 100 390
DEC 81 54 18 63 210 118 154 154 118 DEC 46 64 55 163 210 580 DEC 19 46 37 28 46
mean 115 276 254 389 10,473 229 143 290 946 mean 148 112 125 169 481 836 mean 69 114 51 131 597
std dev 67 553 461 1,061 22,153 194 70 226 2,441 std dev 88 70 131 166 715 1,126 std dev 66 140 23 166 1,431
max 273 2,100 1,640 3,900 60,000 546 280 819 9,000 max 330 290 490 550 2,700 3,900 max 199 570 100 580 5,300
min 28 28 18 5 64 28 28 28 5 min 28 37 19 10 46 55 min 5 19 19 10 37
Geomean 97 122 76 69 875 138 123 204 123 Geomean 120 96 79 100 248 407 Geomean 42 77 46 73 143
44
020406080
10
0
12
0
14
0
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
4
2
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
Fecal Coliform Bacteria (CFU/100 mL)
Fi
g
u
r
e
2
.
7
F
e
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
a
t
t
h
e
Lo
w
e
r
C
a
p
e
F
e
a
r
R
i
v
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r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
st
a
t
i
o
n
s
,
1
9
9
5
-
2
0
1
0
v
e
r
s
u
s
2
0
1
1
.
1995-2010 2011
45
3.0 Water Quality Evaluation by Subbasin in the Lower Cape Fear
River System, 2011
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 2011 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 next
basinwide plan is scheduled to be completed in late 2012.
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
46
the best uses of that water. North Carolina’s Water Quality Standards Program adopted
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://portal.ncdenr.org/web/wq/ps/csu 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/enterococcus bacteria, field turbidity and the nutrient species nitrate-nitrite (referred to as nitrate) and total phosphorus. For dissolved oxygen, chlorophyll a and fecal coliform/enterococcus bacteria LCFRP data
is compared to the N.C. State Water Quality Standards which can be found at
http://portal.ncdenr.org/web/wq/ps/csu. Fecal coliform/enterococcus bacteria data is
compared using human contact standards. A one day value is compared to the standard
which is based on a geometric mean of 5 samples over a 30 day period. Entercoccus
analysis began in July of 2011 at stations BRR, M61, M54, M35, M23 and M18.
The NC DWQ does not have surface water quality standards for nitrate and total
phosphorus. Therefore the AEL water quality standard is based on levels noted to be
47
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 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:
Subbasin # LCFRP Stations
03-06-16 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.
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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
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
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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).
UNCW Aquatic Ecology Laboratory Evaluation
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).
BRN - representative of small tributaries NC11 – Main stem of the Cape Fear River
deep channel, freshwater with minor tidal influence
Dissolved oxygen ratings and chlorophyll a ratings for BRN, HAM and NC11 were all good
for 2011 (Table 3.3.1).
For fecal coliform bacteria concentrations NC11 had a good rating (Table 3.3.1). BRN and
HAM received poor ratings exceeding the standard 50% and 67% of the time, respectively
(Figure 3.3.1).
50
For field turbidity all stations were rated as good (Table 3.3.1). The NC State Standard of 50
NTU was exceeded once at NC11 in December.
For nitrate HAM was rated as good with only one sample exceeding the NC State Standard
in 2011 (Table 3.3.1). NC11 was rated as fair, exceeding the standard 25% of the time.
BRN received a poor rating exceeding the standard 75% of the time (Table, 3.3.1, Figure
3.3.1). All stations rated as good for total phosphorus.
Table 3.3.1 UNCW AEL 2011 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 G G P G G G
NC11 G G G G F G
Figure 3.3.1 Fecal coliform bacteria concentrations at stations BRN and HAM for 2011.
The dashed line represents the NC State Standard, 200 cfu/100 mL.
0
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800
1,000
1,200
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Figure 3.3.2 Nitrate concentrations at BRN for 2011. The dashed line represents the AEL stream standard for nitrate, 200 ug/L.
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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
UNCW Aquatic Ecology Laboratory Evaluation
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.
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, M54, M42, M35, M23, M18 and
SPD (Table 3.4.1). Sites given a fair rating for dissolved oxygen, with the percentage of
samples not meeting the standard shown in parentheses, are DP (17%), IC (17%), NAV (25%), HB (25%), M61 (17%) and BRR (25%). LVC2 was rated poor with samples below
the standard 42% of the time (Figure 3.4.1).
All sites within this subbasin had a good rating for chlorophyll a concentrations (Table
3.4.1). No sample exceeded the 40 µg/L NC State Standard during 2011.
AC, DP, IC, NAV, HB, M42, M35, M23, M18 and SPD rated as good for fecal
coliform/entercoccus bacteria (Table 3.4.1). LVC2, BRR, M61 and M54 rated as fair
exceeding the NC state standard 17%, 25%, 17% and 17% of the time, respectively.
All sites within this subbasin rated good for field turbidity during 2011 except HB which exceeded the NC State Standard 17% of the time giving it a fair rating (Table 3.4.1).
The ten estuary stations were all rated as good for nitrate during 2011 (Table 3.4.1).
AC, DP and IC were rated fair exceeding the UNCW-AEL recommended standard (1,000
g/L for mainstem stations) 25%, 25% and 17% of the time, respectively. LVC2 was rated
as poor for nitrate exceeding the UNCW-AEL recommended standard (200 g/L for stream stations) 58% of the time (Table 3.4.1). All stations rated good for total phosphorus.
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Table 3.4.1 UNCW AEL 20011 evaluation for subbasin 03-06-17
Station Dissolved Oxygen Chlorophyll
a Fec. Coli ECoccus Field Turbidity Nitrate Total Phosphorus
LVC2 P G F G P G
AC G G G G F G
DP F G G G F G
IC F G G G F G
NAV F G G G G G
HB F G G F G G
BRR F G F G G G
M61 F G F G G G
M54 G G F G G G
M42 G G G G 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, rated poor for 2011.
The dashed line shows the NC State Standard of 4.0 mg/L.
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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.
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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
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: Since February 1996
Sampling relevance: Below City of Dunn, hog operations in watershed
SR – a slow black water tributary
SR had a poor rating for dissolved oxygen concentrations in 2011 (Table 3.5.1). The NC State Standard for swampwater of 4.0 mg/L was exceeded 58% of the time (Figure 3.5.1).
SR had a fair rating for chlorophyll a exceeding the NC State standard of 40 µg/L 25% of
the time (Table 3.5.1).
SR had a fair rating for fecal coliform bacteria concentrations exceeding the NC state standard of 200 CFU/100mL in 25% of samples (Table 3.5.1). The highest concentration
was in September (550 cfu/100mL).
SR had a fair rating for field turbidity exceeding the NC state standard 17% of the time.
Nitrate and total phosphorus were rated as good during 2011 (Table 3.5.1).
60
Table 3.5.1 UNCW AEL 2011 evaluation for subbasin 03-06-18
Station Dissolved Oxygen Chlorophyll
a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SR P F F F G G
Figure 3.5.1 Dissolved oxygen (mg/L) at SR during 2011. The dashed line shows the NC
state standard for swampwater DO of 4.0 mg/L.
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6
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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
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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
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: February 1996 to present
Sampling relevance: Many concentrated animal operations (CAOs) within the
watershed, reference areas for point and nonpoint source pollution
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 2011 (Table 3.6.1).
LCO and GCO had a fair rating for fecal coliform bacteria during 2011exceeding the NC
state standard 17% and 25 % of the time, respectively. 6RC had a poor rating for fecal
coliform bacteria with 33% of samples exceeding the NC state human contact standard of
200 CFU/100mL (Table 3.6.1, Figure 3.6.1).
Nitrate levels were rated poor at 6RC, LCO and GCO exceeding 200 µg/L in 75%, 58%,
and 50% 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 as poor with 42% of
samples exceeding the UNCW-AEL recommended standard of 500 g/L (Table 3.6.2).
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Table 3.6.1 UNCW AEL 2011 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 F G P G
GCO G G F G P P
Figure 3.6.1 Fecal coliform bacteria concentrations at 6RC during 2011. The
dashed line shows the NC state standard of 200 cfu/100 mL.
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Figure 3.6.2 Nitrate concentrations (µg/L) at 6RC, LCO, and GCO during 2011. The
dashed line shows the UNCW-AEL standard of 200 g/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
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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
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: February 1996 to present
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
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B210 and COL had a good rating for dissolved oxygen in 2011. BBT had a fair rating as dissolved oxygen concentration dropped below the NC state standard for
swampwaters of 4.0 mg/L 17% of the time (Table 3.7.1).
All three sites were rated good for chlorophyll a, and field turbidity during 2011(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 and total phosphorus COL and B210 rated as good during 2011 (Table 3.7.1).
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 G G
COL G G G G G G
BBT F G G
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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.
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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
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: June 1997 – present
Sampling relevance: Below Mount Olive Pickle Plant
NC403 - slow moving headwaters of NE Cape Fear River
NC403 had a poor rating for dissolved oxygen concentrations dropping below the NC state
standard for swampwater of 4.0 mg/L in 67% 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) 17% 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 50% 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 2011.
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Table 3.8.1 UNCW AEL 2011 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
2011. 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 g/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 58% of the time.
All sites had a good rating for chlorophyll a and field turbidity concentrations (Table 3.9.1). For fecal coliform bacteria concentrations SAR, GS and ROC each had a fair rating with
17%, 25% and 17% of samples above the standard, respectively (Table 3.9.1, Figure
3.9.1). Sites PB and LRC were rated poor with 83% and 45% of samples above the
standard (Figure 3.9.2).
For nitrate GS had a good rating (Table 3.9.1). LRC had a fair rating exceeding the UNCW
AEL standard of 200 g/L 17% of the time. SAR, PB and ROC all had a poor rating with
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levels exceeding the UNCW AEL standard 67%, 42% and 92% of the time, respectively
(Figure 3.9.3).
For total phosphorus SAR, GS and LRC were rated as good (Table 3.9.1). PB was rated as
fair, exceeding the UNCW AEL standard of 500 mg/L in 17% of the samples (Table 3.9.1).
ROC was rated as poor, exceeding the standard 42% of the time.
Table 3.9.1 UNCW AEL 2011 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 G G
PB G G P G P F
LRC G G P G F G
ROC G G F G P P
Figure 3.9.1 Fecal coliform bacteria (cfu/100mL) at SAR, GS and ROC which rated fair
during 2011. The dashed line is the NC State Standard for human contact of 200 cfu/100mL).
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Figure 3.9.2 Fecal coliform bacteria (cfu/100mL) at LRC and PB which rated poor during 2011. The dashed line is the NC State Standard for human contact of 200 cfu/100mL.
Figure 3.9.3 Nitrate concentrations (µg/L) at SAR, PB and ROC which rated poor during
2011. The dashed line represents the UNCW AEL standard of 200 g/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
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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
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
NCF117 - Northeast Cape Fear River at US117
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All sites were rated for dissolved oxygen using the NC state standard for swampwater of 4.0
mg/L. BC117 had a good rating (Table 3.10.1). NCF117, NCF6 and SC-CH had a fair rating with 17%, 25% and 17% of samples sub-standard, respectively. ANC and BCRR had a
poor rating with sub-standard samples 50% and 75% of the time, respectively (Figure
3.10.1).
For chlorophyll a all stations rated good (Table 3.10.1). Chlorophyll a was not analyzed at
SC-CH.
For fecal coliform bacteria NCF117 and NCF6 had a good rating (Table 3.10.1). ANC was rated fair exceeding the standard 17% of the time. BC117, BCRR and SC-CH each had a poor rating, exceeding the human contact standard of 200 cfu/100 mL 58%, 42% and 33%
of the time, respectively (Figure 3.10.2).
All six stations were rated good for field turbidity during 2011 (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 92% 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). BCRR was also rated poor for nitrate, exceeding the
standard 33% of the time. All other sites were rated good for nitrate and total phosphorus.
Nutrients were not analyzed at SC-CH.
Table 3.10.1 UNCW AEL 2011 evaluation for subbasin 03-06-23
Station Dissolved Oxygen Chlorophyll
a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
ANC P G F G G G
BC117 F G P G P P
BCRR P G P G P G
NCF117 F G G G G G
NCF6 F G G G G G
SC-CH G F G
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Figure 3.10.1 Dissolved oxygen concentrations (mg/L) at ANC and BCRR which rated poor during 2011. The dashed line shows the NC state standard for swampwater, 4.0
mg/L.
Figure 3.10.2 Fecal coliform bacteria concentrations (cfu/100mL) at BC117, BCRR and
SC-CH which rated poor during 2011. 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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