ENVIRONMENTAL ASSESSMENT OF THE
LOWER CAPE FEAR RIVER SYSTEM
2002 - 2003
by
Michael A. Mallin, Matthew R. McIver,
Heather A. Wells, Michael S. Williams,
Thomas E. Lankford, and James F. Merritt
CMS Report No. 03-03
Center for Marine Science
University of North Carolina at Wilmington
Wilmington, N.C. 28409
October 2003
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 at
Wilmington (UNCW) perform the sampling effort. The LCFRP currently encompasses
35 water sampling stations throughout the Cape Fear, Black, and Northeast Cape Fear
River watersheds. The LCFRP sampling program includes physical, chemical, and
biological water quality measurements, analyses of the benthic and epibenthic
macroinvertebrate communities, and assessment of the fish communities. Principal
conclusions of the UNCW researchers conducting these analyses are presented below,
with emphasis on the period July 2002-June 2003. 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 characterized by reasonably turbid water
containing moderate to high levels of inorganic nutrients. It is fed by two large
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, algal blooms are
rare because light is attenuated by water color or turbidity, and flushing is high. Periodic
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.
During the 2002-2003 sampling period, a prolonged drought that had been in effect for
over two years ended. The summer of 2002 had been characterized by high salinity in
the estuary and main river channel; low salinities were found in these locations in spring
and early summer 2003. Whereas annual turbidity means remained below the longterm average in the river and estuary, the ending of the drought did lead to increasing
turbidities in the upper estuary. Low dissolved oxygen remained a major problem in the
LCFR basin, with a summer sag in the lower river and upper estuary, and some stream
stations (ANC, NC403, and SR) were impacted severely. Algal blooms were largely
absent in the larger streams but several occurred in smaller, nutrient-impacted streams.
Several stream stations, particularly BCRR, BC117, LRC, BRN and HAM showed high
fecal coliform counts on a number of occasions. Chronic or periodic high nutrient levels
were found at a number of stations, including ANC, BC117, BCRR, LRC, NC403, PB
and SAR. Rockfish Creek (ROC) is showing increasing trends (and sporadic high
levels) of phosphorus and nitrate over the past several years and is a station of
increasing concern. Water column metals concentrations were not problematic during
the period 2002-2003.
This report includes an in-depth look at use support ratings for each subbasin,
comparing the results of the North Carolina Division of Water Quality's 2000 Basinwide
Management Plan with the UNCW-LCFRP's assessments of the 2001-2002 sampling
year. The UNCW-LCFRP utilized definitions for use support 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. UNCW found that 97% of the stations
sampled showed good water quality in terms of turbidity and chlorophyll a. However,
33% of the stations had either fair or poor water quality in terms of fecal coliform
bacterial contamination, and 60% of the stations were fair to poor in terms of dissolved
oxygen concentrations. In addition, UNCW considered 20% of the stations to be
negatively impacted by excessive nutrient loading.
The UNCW-LCFRP conducted an examination of river and stream biochemical oxygen
demand (BOD) over a five-year period in the lower Cape Fear River system, in coastal
North Carolina. Median BOD5 was approximately 1.0 mg/L in the Piedmont-derived
sixth order Cape Fear River and slightly lower in the two fifth order blackwater
tributaries, the Black and Northeast Cape Fear Rivers. BOD in the Cape Fear River
was most strongly correlated with chlorophyll a, whereas in the two blackwater
tributaries BOD was most strongly correlated with phosphorus concentrations and fecal
coliform bacterial counts. This relationship may be a result of nutrient induced
increases in heterotrophy, as previous experimental studies have shown that
phosphorus additions to blackwater streams lead directly to increased bacterial counts
and BOD concentrations. BOD load as lbs BOD/day was correlated much more
strongly with river discharge than BOD concentration in all three rivers, with discharge
alone able to explain from 40-80% of BOD load variability, depending upon the system.
A set of second-to-third order rural streams in the Black River basin was also examined.
Median BOD5 concentrations ranged from 0.9-1.2 mg/L in all six tributaries, regardless
of land use and watershed size. BOD load varied directly with stream flow. In contrast,
BOD5 and BOD20 concentrations in three urban streams in Wilmington, N.C. were
approximately double those of the rural streams, with much higher storm event maxima
in the urban situations.
The reintroduction of electroshocking data from this years survey has given us the
ability to closely monitor fish species richness and disease incidence. Species richness
in samples collected by this gear has shown declines that give cause for concern.
Trend line analysis shows over a 23% drop and this is excluding a seven-month and a
nine-month data gap that would likely have lowered the trend line further due to the time
of year in which they occurred. Although the drought had little, if any effect on overall
fish community structure, non-native percentages, or disease incidence, species
richness reached record levels in the trawling surveys. This suggests the drought
created a more estuarine environment in our sampling area and more estuarine
dependant species were therefore captured. The catches of estuarine dependent
species further reinforces the important role the Cape Fear River system plays as
habitat for not only resident species but estuarine and marine species. Drops in
disease percentages in the electroshocking and gillnets surveys were mostly driven by
the drops in the disease percentage of bowfin. Although most of the trend analysis
showed no discernible patterns in a positive or negative direction, a trend toward
decreasing species richness and catch-per-unit-effort in the electroshocking surveys
may be developing and should be closely monitored in future surveys.
Table of Contents
1.0 Introduction...........................................................................………..................…......1
1.1 Site Description................................................………........................…........2
2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River
and Estuary………………………………………………..……………………........….....7
Physical Parameters..…......................………............................................…....…9
Chemical Parameters…....……..……….........................................................…..12
Biological Parameters.......……….....……......................................................…..15
3.0 Use Support and Water Quality by Sub-basin in the Mid-and-Lower Cape Fear
River System………………………………………………………………………………..53
4.0 Biochemical Oxygen Demand (BOD) Studies in the Lower Cape Fear River
System......................……………………………………………………………………...98
5.0 Fisheries Studies in the Lower Cape Fear River System, July 2001– June
2002.……………………………………………………………………………………....116
1.0 Introduction
Michael A. Mallin
Center for Marine Science
University of North Carolina at 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 July 2002 through June 2003.
The scientific basis of the Program 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. 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 at 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 (directed by Dr. Michael Mallin). Sampling was increased
to 34 stations in February of 1996, and 35 stations in February 1998. 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 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. The third major biotic component (added in January 1996) was an
extensive fisheries program directed by Dr. Mary Moser of the UNCW Center for Marine
Science Research, with subsequent (1999) overseeing by Mr. Michael Williams and Dr.
Thomas Lankford of UNCW-CMS. This program involved cooperative sampling with the
North Carolina Division of Marine Fisheries and the North Carolina Wildlife Resources
Commission. The fisheries program ended in December 1999, but was renewed with
additional funds from the Z. Smith Reynolds Foundation from spring – winter 2000, and
has been operational since that period.
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 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 blackwater streams drain extensive riverine swamp forests and
add organic color to the mainstem. The watershed is the most heavily industrialized in
North Carolina, and contains 280 permitted wastewater discharges (NCDENR 2000)
and approximately 1.5 million people residing in the basin. Approximately 24% of the
land use in the watershed is devoted to agriculture and livestock production (NCDENR
2000), particularly swine and poultry operations. Thus, the watershed receives
considerable point and non-point source loading of pollutants.
Water quality is monitored by boat at ten stations in the Cape Fear Estuary (from
Navassa to Southport) and one station in the Northeast Cape Fear Estuary (Table 1.1;
Fig. 1.1). Riverine stations sampled by boat include NC11, AC, DP, IC, and BBT (Table
1.1; Fig. 1.1). NC11 is located upstream of any major point source discharges in the
lower river and estuary system, and is considered to be representative of water quality
entering the lower system. BBT is located on the Black River between Thoroughfare
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). Data collection at a station in the Atlantic Intracoastal Waterway was
initiated in February 1998 to obtain water quality information near the Southport
Wastewater Treatment Plant discharge.
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.uncwil.edu/cmsr/aquaticecology/lcfrp/
This report contains four sections assessing LCFRP data. Section 2 presents an
overview of physical, chemical, and biological water quality data from the 35 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, compare our results with DWQ's
2000 Basinwide Plan, and make use support assessments for dissolved oxygen,
turbidity, chlorophyll a, metals, and fecal coliform bacterial abundance. We also utilize
other relevant parameters such as nutrient load 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.
Section 4 presents an assessment of biochemical oxygen demand (BOD) in the three
main tributaries (the Cape Fear, Black, and Northeast Cape Fear Rivers), as well as six
rural tributaries. BOD comparisons and loading data are compared by location and
factors influencing concentration and load are discussed. These data are also
compared with urban stream BOD data from Wilmington City streams. In Sections 5 we
present an assessment of the fish community of the Lower Cape Fear basin, as
captured and analyzed by three different methods.
1.2. References Cited
NCDENR. 2000. Cape Fear River Basinwide Water Quality Plan. North Carolina
Department of Environment and Natural Resources, Division of Water Quality, Water
Quality Section, Raleigh, NC, 27699-1617.
Table 1.1. Description of sampling locations in the Cape Fear Watershed, 2002 - 2003,
including UNCW designation and NCDWQ map number.
________________________________________________________________
UNCW St. DWQ No.
Location
________________________________________________________________
High order river and estuary stations
NC11
GPS
59
At NC 11 bridge on Cape Fear River (CFR)
N 34.39663
W 78.26785
LVC
GPS
74
40 m up Livingston Creek from Cape Fear River
N 34.35180
W 78.20128
AC
GPS
61
5 km downstream from International Paper on CFR
N 34.35547
W 78.17942
DP
GPS
92
At Dupont Intake above Black River
N 34.33595
W 78.05337
IC
GPS
71
Cluster of dischargers upstream of Indian Cr. on CFR
N 34.30207
W 78.01372
B210
GPS
70
Black River at Highway 210 bridge
N 34.43138
W 78.14462
BBT
GPS
none
Black River between Thoroughfare and Cape Fear River
N 34.35092
W 78.04857
NCF117
GPS
84
Northeast Cape Fear River at Highway 117, Castle Hayne
N 34.36342
W 77.89678
NCF6
GPS
85
Northeast Cape Fear River near GE dock
N 34.31710
W 77.95383
NAV
GPS
72
Railroad bridge over Cape Fear River at Navassa
N 34.25943
W 77.98767
HB
GPS
73
Cape Fear River at Horseshoe Bend
N 34.24372
W 77.96980
BRR
GPS
75
Brunswick River near new boat ramp in Belville
N 34.22138
W 77.97868
M61
GPS
86
Channel Marker 61, downtown at N.C. State Port
N 34.19377
W 77.95725
M54
GPS
87
Channel Marker 54, 5 km downstream of Wilmington
N 34.13933
W 77.94595
M42
GPS
88
Channel Marker 42 near Keg Island
N 34.09017
W 77.93355
M35
GPS
89
Channel Marker 35 near Olde Brunswick Towne
N 34.03408
W 77.93943
M23
GPS
90
Channel Marker 23 near CP&L intake canal
N 33.94560
W 77.96958
M18
GPS
91
Channel Marker 18 near Southport
N 33.91297
W 78.01697
SPD
93
1000 ft W of Southport WWT plant discharge on ICW
GPS
N 33.91708
W 78.03717
________________________________________________________________
Tributary stations collected from land
________________________________________________________________
SR
GPS
62
South River at US 13, below Dunn runoff
N 35.15600
W 78.64013
GCO
GPS
63
Great Coharie Creek at SR 1214
N 34.91857
W 78.38873
LCO
GPS
64
Little Coharie Creek at SR 1207
N 34.83473
W 78.37087
6RC
GPS
65
Six Runs Creek at SR 1003 (Lisbon Rd.)
N 34.79357
W 78.31192
BRN
GPS
66
Browns Creek at NC 87
N 34.61360
W 78.58462
HAM
GPS
67
Hammonds Creek at SR 1704
N 34.56853
W 78.55147
COL
GPS
68
Colly Creek at NC 53
N 34.46500
W 78.26553
ANC
GPS
69
Angola Creek at NC 53
N 34.65705
W 77.73485
NC403
GPS
94
Northeast Cape Fear below Mt. Olive Pickle at NC403
N 35.17838
W 77.98028
PB
GPS
77
Panther Branch below Cates Pickle
N 35.13445
W 78.13630
GS
GPS
78
Goshen Swamp at NC 11
N 35.02923
W 77.85143
SAR
GPS
79
Northeast Cape Fear River near Sarecta
N 34.97970
W 77.86251
LRC
GPS
80
Little Rockfish Creek at NC 11
N 34.72247
W 77.98145
ROC
GPS
81
Rockfish Creek at US 117
N 34.71689
W 77.97961
BCRR
GPS
82
Burgaw Canal at Wright St., above WWTP
N 34.56334
W 77.93481
BC117
GPS
83
Burgaw Canal at US 117, below WWTP
N 34.56391
W 77.92210
2.0- Physical, Chemical, and Biological Characteristics of the
Lower Cape Fear River and Estuary
Matthew R. McIver and Michael A. Mallin
Center for Marine Science
University of North Carolina at Wilmington
2.1 - Introduction
This section of the report includes a discussion of the physical, chemical, and biological
water quality parameters, concentrating on the 2002-2003 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, turbidity, salinity, conductivity and pH. The chemical
makeup of the Cape Fear River was investigated by measuring the magnitude and
composition of nitrogen and phosphorus in the water, as well as concentrations of United
States Environmental Protection Agency (US EPA) priority pollutant metals. 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 which has been approved by the NC Division
of Water Quality.
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 610D (or 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
the physical parameters were measured at a depth of 0.1 m.
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. 0.2 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 Technicon AutoAnalyzer (Method 365.5). In this technique the orthophosphate in
each sample reacts with ammonium molybdate and anitmony potassium tartrate in an
acidic medium (sulfuric acid) to form an anitmony-phospho-molybdate complex. The
complex is then reacted with ascorbic acid and forms a deep blue color. The intensity of
the color is measured at a wavelength of 880 nm by a colorimeter and displayed on a chart
recorder. Standards and spiked samples were analyzed for quality assurance.
Biological Parameters
Fecal Coliform Bacteria
Fecal coliform bacteria were analyzed at a state-certified laboratory contracted by LCFRP.
Samples were collected approximately 0.2 m below the surface in sterile plastic bottles
provided by the contract laboratory and placed on ice for no more than six hours before
analysis.
Chlorophyll a
The analytical method used to measure chlorophyll a is described in Welschmeyer (1994)
and US EPA (1997) and was performed by CMS personnel. Chlorophyll a concentrations
were determined directly from the 1.0 micron filters used for filtering samples for
orthophosphate analysis. All filters were wrapped individually in foil, placed in airtight
containers and stored in the freezer. During analysis each filter is immersed in 10 mL of
90% acetone for 24 hours, which extracts the chlorophyll a into solution. Chlorophyll a
concentration of each solution is 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.
Biochemical Oxygen Demand (BOD)
Five sites were 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 this sampling period additional BOD data were
collected at stream stations LVC, 6RC, LCO, GCO, BRN, HAM and COL. 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 5 hours of sample collection. Samples were analyzed in duplicate.
Dissolved oxygen measurements were made using a YSI Model 57 meter that was aircalibrated. No adjustments were made for pH since most all samples exhibited pH values
within or very close to the desired 6.5-7.5 range. Several 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.
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 July 2002-June 2003. Discussion of the data
focuses mainly on the river channel stations, but poor water quality conditions at stream
stations will also be discussed. 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 hurricanes in 1996, 1998, and 1999);
however, there was higher than average rainfall during the latter portion of this sampling
period, in contrast to the drought last year. Therefore this report reflects mixed flow
conditions for the Cape Fear River and Estuary.
Physical Parameters
Water temperature
Water temperatures at all stations ranged from 3.9 to 30.5 oC and individual station annual
averages ranged from 15.9 to 19.5 oC (Table 2.1). Highest temperatures occurred during
July (all station mean = 27.8) and lowest temperatures during January (all station mean =
7.7). Stream stations were generally cooler than river stations, most likely because of
shading and lower nighttime air temperatures affecting the shallower waters.
Salinity
Salinity at the estuarine stations ranged from 0.0 to 34.4 parts per thousand (ppt) and
station annual means ranged from 2.4 to 26.0 ppt (Table 2.2). Lowest salinity occurred in
June 2003 (all stations mean = 2.6) and highest salinity occurred in July 2002 (all stations
mean = 22.1). Two stream stations, NC403 and SAR, had occasional oligohaline
conditions due to discharges from pickle production facilities. Annual mean salinity for
2002-2003 was higher than the eight-year average for 1995-2003 at all stations (Figure
2.1).
Conductivity
Conductivity at estuarine stations ranged from 0.1 to 52.3 mS/cm and from 0.0 to 7.7
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.
pH
pH values ranged from 3.3 to 10.3 and stations annual medians ranged from 3.7 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. Some unusually high
pH values at LRC,BC117 and ANC are most likely due to industrial discharges and or algal
blooms (see also very high dissolved oxygen concentrations). Low pH values at COL
predominate because of naturally acidic blackwater inputs.
Dissolved Oxygen
Dissolved oxygen (DO) problems are a major water quality concern in the Cape Fear River
(Mallin et al. 1997; 1998a; 1998b; 1999a; 1999b). Concentrations ranged from 0.1 to 16.8
mg/L and station annual means ranged from 3.4 to 10.6 mg/L (Table 2.5). Average annual
DO levels at the river channel stations were higher for 2002-2003 than the average for
1995-2003 (Figure 2.2). Dissolved oxygen levels were lowest during the summer (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. These hypoxic conditions
could have negative impacts on the biota in the Cape Fear River.
There is an 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. Mean oxygen levels
were highest at the upper river stations NC11 (9.0 mg/L) and AC (8.6 mg/L) and in the
middle to lower estuary at stations M42 (8.3 mg/L) and M23 (8.4 mg/L). Lowest DO levels
were at the lower river and upper estuary stations IC (7.4 mg/L ) and NAV (7.5 mg/L).
Discharge of high BOD waste from the paper/pulp mill just above the AC station, as well as
inflow of blackwater from the Northeast Cape Fear and Black Rivers, helps to diminish
oxygen in the upper estuary. 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 mean = 6.5, B210 mean = 7.2). These rivers are
classified as blackwater systems because of their tea colored water. As the water passes
through swamps en route to the river channel, tannins from decaying vegetation leach into
the water, resulting in the observed color. Decaying vegetation on the swamp floor has an
elevated biochemical oxygen demand and usurps oxygen from the water, leading to
naturally low dissolved oxygen levels. Runoff from concentrated animal feeding operations
(CAFOs) may also contribute to chronic low dissolved oxygen levels in these blackwater
rivers (Mallin et al. 1998b; 1999a; Mallin 2000).
Several stream stations were severely stressed in terms of low dissolved oxygen during
the year July 2002-June 2003. These included ANC, NC403, BCRR and SR (Table 2.5).
Some of this can be attributed to low water conditions; however point-source discharges
also likely contribute to low dissolved oxygen at NC403 and possibly SR, especially via
nutrient loading (Mallin et al. 2001; Mallin et al. 2002).
Field Turbidity
Turbidity levels ranged from 0 to 140 nephelometric turbidity units (NTU) and station
annual means ranged from 2 to 28 NTU (Table 2.6). Annual mean turbidity levels for
2002-2003 were lower than the 1995-2003 averages at the river stations and lower
estuary, but higher at the mid-upper estuary stations (Figure 2.3). Turbidity was highest at
the upper river stations, reaching a maximum at the upper estuary, and declining toward
the lower estuary. Turbidity was lowest in the blackwater tributaries (Northeast Cape Fear
River and Black River).
Note: 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 substantially lower than field turbidity. We therefore recommend that
NCDWQ investigate the utilization of field rather than laboratory turbidity in order to obtain
data more representative of natural conditions.
Total Suspended Solids
Total suspended solid (TSS) values ranged from 0 to 109 mg/L with station annual means
from 1 to 22 mg/L (Table 2.7). For the river channel stations TSS was highest in the
middle estuary at Marker 42 (mean = 22). Highest monthly means for TSS occurred in
winter and spring. Although total suspended solids (TSS) and turbidity both quantify
suspended material in the water column, they do not always go hand in hand. High TSS
does not mean high turbidity and vice versa. This anomaly may be explained by the fact
that fine clay particles are effective at dispersing light and causing high turbidity readings,
while not resulting in high TSS. On the other hand, large organic or inorganic particles
may be less effective at dispersing light, yet their greater mass results in high TSS levels.
Light Attenuation
The attenuation of solar irradiance through a water column is measured by a
dimensionless 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. Light attenuation ranged from 0.66 to 5.63 k/m and station annual means
ranged from 1.51 to 3.70 k/m (Table 2.8). Annual light attenuation means for this
monitoring period were lower than for the eight-year period 1995-2003 (Figure 2.4).
High light attenuation did not always coincide with high turbidity. Blackwater, though low in
turbidity, may increase light attenuation 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.
Chemical Parameters – Nutrients
Total Nitrogen
Total nitrogen (TN) ranged from 90 to 17,900 g/L and station annual means ranged from
541 to 9,233 g/L (Table 2.9). Mean total nitrogen was higher this monitoring period than
for the eight-year mean at all but one channel station (Figure 2.5). Previous research
(Mallin et al. 1999a) has shown a positive correlation between river flow and TN in the
Cape Fear system. Total nitrogen concentrations remained fairly constant down the river
and 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. The pulp mill above AC is a source of TN, increasing levels at this station over
levels at NC11. The blackwater rivers maintained TN concentrations somewhat lower than
those found in the mainstem Cape Fear River. One stream station, BC117, had a very
high mean of 9,233 g/L, presumably from upstream wastewater discharge. ROC has
recently begun to show high levels of TN as well (mean 2,079 g/L) although the source is
not known at this point in time. Temporal patterns for TN were not evident.
Nitrate+Nitrite
Nitrate+nitrite (henceforth referred to as nitrate) is the main species of inorganic nitrogen in
the Lower Cape Fear River. Concentrations ranged from 5 (detection limit) to 16,800 g/L
and station annual means ranged from 47 to 8,245 g/L (Table 2.10). Station annual
means for the 2002-2003 monitoring period were mostly higher than the eight-year means
(Figure 2.6). The highest riverine nitrate levels were at NC11 (mean = 719 g/L) indicating
that much of this nutrient is imported from upstream. Moving downstream from NC11,
nitrate levels decrease most likely as a result of uptake by primary producers and tidal
dilution. The blackwater rivers carried low loads of nitrate compared to the mainstem
Cape Fear stations, though the Northeast Cape Fear River (NCF117 mean = 226 g/L)
had higher nitrate than the Black River (B210 = 129 g/L). No clear temporal pattern was
observable for nitrate.
Several stream stations showed high levels of nitrate on occasion including SAR, NC403,
PB, ROC, BC117. NC403 and PB are downstream of industrial wastewater discharges
and ROC primarily receives non-point agricultural or animal waste drainage. BC117, with
high nitrate levels, exceeded the North Carolina State drinking water standard of 10 mg/L
on five occasions. The Town of Burgaw wastewater plant, upstream of BC117, has no
nitrate discharge limits.
Ammonium
Ammonium concentrations ranged from 10 (detection limit) to 1,180 g/L and station
annual means ranged from 44 to 224 g/L (Table 2.11). This monitoring period the mean
ammonium levels were generally higher than the eight-year means at the channel stations
(Figure 2.6). Areas with the highest ammonium levels this monitoring period included AC
(mean = 199 g/L), which is below a pulp mill discharge, M61 (mean = 120 g/L), and M54
(mean = 125 g/L) in the middle estuary. Ocean dilution accounts for decreasing levels
down into the estuary. At the stream stations, areas with high levels of ammonium include
LVC, ANC, BC117, PB, and BCRR.
Total Kjeldahl Nitrogen
Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen
plus ammonium. TKN ranged from 50 to 3,420 g/L and station annual means ranged
from 429 to 1,462 g/L (Table 2.12). Mean TKN for this monitoring period was mostly
higher than the eight-year mean at the channel stations (Figure 2.8). TKN concentration
drops down through the estuary, likely due to ocean dilution and food chain uptake of
nitrogen. Measured TKN levels in the blackwater rivers are usually higher than in the
mainstem Cape Fear River as a result of the high concentration of organic materials
dissolved in the water (Figure 2.8). The stream stations typically have higher TKN as a
result of the influence of swamp water with high organic and ammonium content. There
were somewhat higher TKN levels during summer months.
Total Phosphorus
Total phosphorus (TP) concentrations ranged from 10 (detection limit) to 4,740 g/L and
station annual means ranged from 35 to 1,563 g/L (Table 2.13). Mean TP for this
monitoring period was lower than the eight-year mean at all channel stations but one
(Figure 2.8). TP is highest at the upper riverine channel stations and declines
downstream into the estuary. Some of this decline is attributable to the settling of
phosphorus-bearing turbidity, yet incorporation of phosphorus into the food chain is also
responsible. A temporal pattern of higher summer TP is a result of increasing
orthophosphate, as the spatial pattern of TP is similar to that of orthophosphate.
At the stream stations several areas had high TP including BC117, NC403, and ROC.
Some of these stations (BC117, NC403) are downstream of industrial or wastewater
discharges.
Orthophosphate
Orthophosphate ranged from 0 to 3,740 g/L and station annual means ranged from 5 to
1,409 g/L (Table 2.14). The 2002-2003 annual means at the channel stations were
higher about half the time and lower half the time than the eight-year means (Figure 2.9).
Much of the orthophosphate load is imported into the Lower Cape Fear system from
upstream areas, as NC11 typically has the highest levels. The Northeast Cape Fear River
had higher orthophosphate levels than the Black River. Orthophosphate can bind to
suspended materials and is transported downstream via turbidity; thus high levels of
turbidity at the uppermost river stations may be an important factor in the high
orthophosphate levels. Turbidity declines toward the estuary because of settling, and
orthophosphate concentration also declines. In the estuary, primary productivity helps
reduce orthophosphate concentrations by assimilation into biomass. Orthophosphate
levels typically reach maximum concentrations during summertime, when anoxic sediment
releases bound phosphorus. Also, in the Cape Fear Estuary, summer algal productivity is
limited by nitrogen, thereby allowing the accumulation of orthophosphate (Mallin et al.
1997; 1999a). In spring, productivity in the estuary is usually limited by phosphorus (Mallin
et al. 1997; 1999a).
The stream stations BC117 and ROC had very high orthophosphate levels while SAR and
NC403 had moderately high levels. NC403 and BC117 are strongly influenced by
industrial and municipal wastewater discharges, and SAR and ROC by agriculture/animal
waste runoff. There is a trend of increasing orthophosphate at ROC since 1996, which will
be investigated more closely in the coming year.
Chemical Parameters - EPA Priority Pollutant Metals
Aluminum levels in the Lower Cape Fear system were generally higher in the upper river
and decreased toward the lower estuary (Table 2.15). Stream stations were generally low
except COL which is considered pristine swamp water. There is no North Carolina aquatic
standard for aluminum.
Arsenic, cadmium, and chromium all maintained concentrations below detection limits at
all stations (except two stations in February) throughout the year (Tables 2.16, 2.17, and
2.18).
Copper concentrations periodically exceeded the state tidal saltwater standard of 3 g/L at
some of the estuarine stations each month (Table 2.19). The freshwater standard of 7
g/L was never exceeded at the upper river stations.
The LCFRP is an iron-rich system (Table 2.20). All of the freshwater stations except for
NCF117, BC117, and COL maintained average iron concentrations near or above the
state standard of 1000 g/L. Iron concentrations generally decreased down-estuary.
Water-column concentrations of lead, mercury, and nickel were below the analytical
detection limit except for three occasions for nickel (Table 2.21, 2.22, 2.23).
Zinc concentrations remained below the state standard at all stations but showed highest
values at BC117 (Table 2.24).
Biological Parameters
Chlorophyll a
During this monitoring period chlorophyll a was generally low at the river and estuarine
stations (Table 2.25). Chlorophyll a ranged from 0.1 to 177.8 g/L and station annual
means ranged from 1.0 to 22.4 g/L. Production of chlorophyll a biomass is low to
moderate in this system primarily because of light limitation by turbidity in the mainstem
and high organic color and low inorganic nutrients in the blackwater rivers. Spatially,
highest values are normally found in the mid-to-lower estuary stations because light
becomes more available downstream of the estuarine turbidity maximum (Figure 2.11).
Chlorophyll a production is extremely limited in the large blackwater tributaries. Highest
chlorophyll a concentrations were found during spring and summer. There was no clear
pattern of differences in mean annual levels at the channel stations from the eight-year
mean.
Substantial phytoplankton blooms do occur at the stream stations (Table 2.25). These
streams are generally shallow, so mixing does not carry phytoplankton cells down below
the critical depth where respiration exceeds photosynthesis. Thus, when flow conditions
permit, 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 readily occur. When blooms occur in blackwater stream stations, they can
become sources of BOD upon death and decay, reducing further the low summer
dissolved oxygen conditions common to these waters (Mallin et al. 2001; 2002).
Particularly large stream algal blooms occurred this year at GS, PB, LRC, SR and BCRR,
with smaller blooms at ANC and LRC (Table 2.25).
Biochemical Oxygen Demand
For the main stem river, mean annual five-day biochemical oxygen demand (BOD5)
concentrations were highest at AC, on average about 30% higher than at NC11 suggesting
influence from the pulp/paper mill inputs (Table 2.26). BOD was somewhat lower during
the winter.
A project aimed at assessing rural stream contributions to BOD was continued this
monitoring period. Results of BOD in several stream stations can be seen in Table 2.26.
HAM showed the highest BOD5 and BOD20 levels, with very little difference among the
other stream stations. The BOD studies are detailed in Chapter 4 of this report.
Fecal Coliform Bacteria
Fecal coliform (FC) bacterial counts ranged from 0 to 4,360 cfu/100 mL and station annual
geometric means ranged from 1 to 195 cfu/100 mL (Table 2.27). No clear temporal
pattern is evident. The state human contact standard (200 CFU) was not exceeded at the
channel stations during any month. FC counts this monitoring period were higher at the
Cape Fear River stations but lower at the estuary stations and the blackwater stations
compared with the eight-year average (Figure 2.12). FC bacteria show a notable spatial
trend of highest counts in the upper estuary-lower river area bounded by IC, NAV, HB, and
BRR.
Most stream stations surpassed the state standard for human contact of 200 CFU/100 mL
on at least one occasion. BCRR, BC117, LRC, BRN, and HAM all had particularly high
levels on at least one occasion. LRC is located below a point source discharge and the
other sites are primarily influenced by non-point source pollution.
2.4 - References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed.
American Public Health Association, Washington, D.C.
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. 1998b. 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. 1999a. Alternation
of factors limiting phytoplankton production in the Cape Fear Estuary. Estuaries
22:985-996.
Mallin, M.A. 2000. Impacts of industrial-scale swine and poultry production on rivers and
estuaries. American Scientist 88:26-37.
Mallin, M.A., 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.
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.
Table 2.1 Water Temperature (degrees C) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
72
NAV
29.5
29.7
27.0
26.4
16.0
9.6
7.9
7.3
9.5
13.9
23.6
20.8
18.4
8.4
29.7
7.3
73
HB
29.9
29.9
27.3
26.6
16.0
9.5
8.5
7.5
9.9
14.3
23.7
21.0
18.7
8.3
29.9
7.5
75
BRR
29.6
30.0
27.4
26.7
16.1
9.1
8.0
7.1
9.8
14.3
23.5
21.0
18.6
8.5
30.0
7.1
86
M61
30.1
29.5
27.8
27.3
16.8
10.2
8.5
7.6
10.0
14.7
23.8
21.6
19.0
8.3
30.1
7.6
87
M54
29.7
29.4
27.8
26.9
17.0
10.0
8.5
7.9
10.4
14.8
23.5
22.1
19.0
8.2
29.7
7.9
88
M42
29.2
29.6
28.1
26.8
17.1
9.6
8.5
8.3
10.9
15.0
23.6
21.9
19.1
8.1
29.6
8.3
89
M35
28.9
29.0
28.3
26.7
17.4
10.3
9.8
8.7
10.6
15.3
23.7
23.1
19.3
7.8
29.0
8.7
90
M23
28.4
28.5
28.0
26.5
17.8
10.7
9.0
8.7
10.9
14.8
23.4
24.0
19.2
7.7
28.5
8.7
91
M18
28.2
28.0
28.0
26.4
18.1
11.4
11.3
8.6
11.1
15.4
23.2
24.0
19.5
7.3
28.2
8.6
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
69
ANC
23.8
24.8
23.1
21.9
11.8
5.1
7.9
8.2
12.9
18.7
24.6
18.6
16.8
6.9
24.8
5.1
79
SAR
25.1
26.8
22.9
22.6
12.1
4.3
6.8
7.7
11.7
17.9
24.2
19.4
16.8
7.6
26.8
4.3
78
94
77
GS NC403 PB
25.7 26.2 26.9
26.7 27.0 28.6
23.4 23.2 25.4
22.9 23.5 28.8
11.8 12.2 11.5
4.2
4.3
3.9
7.3
6.5
6.1
8.1
6.7
8.0
11.7 10.8 10.6
19.5 15.9 17.3
25.4 23.9 24.3
18.7 19.5 20.0
17.1 16.6 17.6
7.7
7.9
8.9
26.7 27.0 28.8
4.2
4.3
3.9
80
LRC
30.5
26.2
23.7
24.5
12.9
6.3
8.6
8.4
11.6
16.8
23.7
21.6
17.9
7.8
30.5
6.3
81
83
82
RO C BC117 BCRR
28.1 25.0 23.5
27.5 26.5 24.3
23.3 22.7 23.5
24.1 24.9 22.6
12.2 16.2 12.0
5.8
8.0
5.3
7.0
8.6
7.4
6.8
8.6
7.0
12.1 10.9 10.2
16.3 14.6 14.7
24.2 23.2 21.3
20.6 19.4 19.2
17.3 17.4 15.9
8.0
6.8
7.0
28.1 26.5 24.3
5.8
8.0
5.3
93
SPD
28.2
28.2
28.3
26.8
17.0
10.3
9.8
9.0
11.0
14.9
23.7
23.7
19.2
7.7
28.3
9.0
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
59
74
NC11 LVC
30.2 29.6
30.0 29.5
25.3 24.4
27.1 26.2
14.2 14.5
10.0
9.9
7.5
7.1
7.1
7.2
8.4
8.8
13.8 15.9
22.8 24.3
20.6 20.9
18.1 18.2
8.5
8.3
30.2 29.6
7.1
7.1
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
65
6RC
25.7
22.7
25.1
23.1
12.1
6.2
6.3
9.0
13.2
16.4
20.9
21.9
16.9
7.0
25.7
6.2
64
LCO
26.4
23.0
24.6
23.8
12.2
6.4
6.0
8.7
13.0
16.6
21.1
22.2
17.0
7.2
26.4
6.0
61
AC
29.8
29.9
25.8
26.6
14.5
10.3
7.6
7.2
8.5
13.9
23.3
20.6
18.2
8.4
29.9
7.2
92
DP
29.8
29.4
26.6
26.4
14.9
9.4
7.6
7.2
8.7
14.2
23.6
20.6
18.2
8.5
29.8
7.2
BBT
29.8
29.5
26.7
25.9
14.7
9.0
7.4
7.3
10.2
14.8
23.6
20.9
18.3
8.4
29.8
7.3
71
IC
30.2
29.4
26.9
26.3
15.0
9.4
7.8
7.1
9.4
14.5
23.7
20.8
18.4
8.5
30.2
7.1
85
70
84
NCF6 B210 NC F117
30.1 28.6
29.2
29.4 27.8
29.4
27.2 25.3
26.1
26.4 25.4
25.7
16.5 14.3
17.4
11.2
7.5
9.9
8.8
6.8
8.2
8.3
8.6
7.4
12.8 11.6
11.5
17.3 16.6
16.5
24.0 22.3
24.3
21.6 21.4
21.1
19.5 18.0
18.9
7.7
7.8
7.8
30.1 28.6
29.4
8.3
6.8
7.4
63
GC O
26.5
23.5
24.4
23.1
11.8
6.1
6.1
10.2
13.5
16.3
20.8
22.7
17.1
7.0
26.5
6.1
62
SR
26.2
26.5
23.9
23.0
12.0
5.7
5.9
9.5
12.7
16.8
14.9
21.2
16.5
7.2
26.5
5.7
66
BRN
25.3
23.6
25.9
23.6
12.6
7.8
8.0
12.0
13.3
19.3
19.4
24.1
17.9
6.5
25.9
7.8
67
68
HAM CO L
24.4 25.8
23.3 20.6
24.6 25.7
22.5 22.6
13.1 13.4
6.4
6.2
7.2
5.8
9.3
8.2
11.3 12.2
17.2 16.1
18.5 20.2
22.8 20.4
16.7 16.4
6.7
6.9
24.6 25.8
6.4
5.8
All station
mean
27.8
27.4
25.6
25.2
14.4
8.0
7.7
8.1
11.0
15.9
22.8
21.3
Table 2.2 Salinity (psu) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
72
73
75
86
87
88
89
90
91
85
93
All stations
month
NAV
HB
BRR
M61
M54
M42
M35
M23
M18
NCF6
SPD
mean
JUL
10.6
14.0
15.0
18.6
20.7
24.1
28.3
32.7
34.4
11.1
33.4
22.1
AUG
10.6
14.1
14.5
19.7
20.6
22.1
26.4
30.7
32.5
14.1
31.6
21.5
SEP
0.1
1.7
2.2
6.7
10.3
13.6
18.3
26.4
29.3
2.1
27.5
12.6
OCT
4.0
8.2
10.1
14.0
16.4
18.1
22.1
27.9
30.6
0.5
28.7
16.4
NOV
0.1
0.1
1.5
5.1
8.5
10.8
16.1
25.1
27.4
3.5
27.9
11.5
DEC
2.8
2.0
2.1
6.7
8.8
10.0
16.8
23.8
28.7
0.2
27.3
11.7
JAN
0.1
0.1
0.1
0.3
1.8
2.1
10.0
11.4
28.7
0.1
17
6.5
FEB
0.2
0.6
0.2
2.8
6.7
10.6
17.4
28.1
31.1
1.1
24.6
11.2
MAR
0.0
0.0
0.1
0.1
0.1
1.2
4.6
15.2
16.9
0.1
17.1
5.0
4.9
APR
0.0
0.0
0.0
0.1
0.1
0.6
3.7
10.1
25.5
0.1
14.2
MAY
0.0
0.1
0.1
1.1
2.0
3.9
5.8
10.6
14.9
0.1
19.4
5.3
JUN
0.0
0.0
0.0
0.0
0.0
0.1
1.7
6.3
12.1
0.0
8.8
2.6
23.1
mean
2.4
3.4
3.8
6.3
8.0
9.8
14.3
20.7
26.0
2.8
std dev
3.9
5.2
5.6
7.0
7.4
8.1
8.6
8.9
7.0
4.6
7.3
max
10.6
14.1
15.0
19.7
20.7
24.1
28.3
32.7
34.4
14.1
33.4
min
0.0
0.0
0.0
0.0
0.0
0.1
1.7
6.3
12.1
0.0
8.8
Table 2.3 Conductivity (mS/cm) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
72
NAV
18.05
18.07
0.29
7.33
0.21
5.20
0.12
0.37
0.09
0.09
0.09
0.07
4.2
6.6
18.1
0.1
73
75
86
87
88
89
90
91
93
HB
BRR M61 M54 M42 M35 M23 M18 SPD
23.39 24.85 30.23 33.25 38.18 44.03 51.06 52.34 51.04
23.50 24.07 31.80 32.95 35.21 41.32 47.27 49.69 48.61
3.21
4.20 11.71 17.57 22.66 29.79 41.34 45.36 42.81
13.90 16.94 23.27 26.68 29.43 35.17 43.42 47.31 44.56
0.21
2.81
9.05 14.65 18.11 26.25 39.12 42.68 43.30
3.80
3.89 11.78 15.25 16.95 27.37 37.77 44.58 42.70
0.18
0.20
0.51
3.10
4.16 17.03 19.14 44.55 27.81
1.13
0.35
5.20 11.75 18.00 28.26 43.84 47.84 38.96
0.09
0.12
0.13
0.24
2.31
8.18 25.58 27.44 27.79
0.10
0.09
0.10
0.11
1.22
6.72 17.13 39.92 23.35
0.10
0.18
2.20
3.80
6.94 10.31 17.97 24.49 31.15
0.07
0.07
0.08
0.09
0.24
3.33 11.09 20.59 15.04
5.8
6.5
10.5
13.3
16.1
23.1
32.9
40.6
36.4
8.7
9.2
11.3
11.9
12.8
13.2
13.2
10.0
10.7
23.5
24.9
31.8
33.2
38.2
44.0
51.1
52.3
51.0
0.1
0.1
0.1
0.1
0.2
3.3
11.1
20.6
15.0
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
59
74
NC11 LVC
0.22
0.24
0.21
0.40
0.12
0.11
0.16
0.18
0.15
0.26
0.13
0.14
0.10
0.12
0.11
0.18
0.08
0.14
0.08
0.16
0.07
0.68
0.07
0.15
0.1
0.2
0.0
0.2
0.2
0.7
0.1
0.1
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
69
ANC
0.11
0.12
0.10
0.18
0.20
0.17
0.17
0.14
0.11
0.09
0.08
0.06
0.1
0.0
0.2
0.1
79
SAR
0.16
0.30
0.33
0.28
0.24
0.20
0.17
0.18
0.14
0.13
0.12
0.10
0.2
0.1
0.3
0.1
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
65
6RC
0.13
0.15
0.13
0.13
0.12
0.15
0.14
0.13
0.12
0.11
0.10
0.08
0.1
0.0
0.1
0.1
78
94
GS NC 403
0.20
0.65
0.31
0.45
0.31
0.23
0.26
0.71
0.24
0.64
0.19
0.30
0.16
0.29
0.17
0.39
0.14
0.26
0.13
0.31
0.12
0.41
0.10
0.24
0.2
0.4
0.1
0.2
0.3
0.7
0.1
0.2
77
PB
7.71
3.43
0.61
5.02
2.95
0.84
0.70
1.74
0.75
1.13
2.39
0.70
2.3
2.1
7.7
0.6
80
LRC
0.17
0.15
0.11
0.20
0.17
0.14
0.14
0.17
0.12
0.12
0.11
0.07
0.1
0.0
0.2
0.1
81
83
RO C BC 117
0.36
0.95
0.52
0.84
0.28
0.16
0.32
0.97
0.75
1.03
0.26
0.47
0.18
0.36
0.17
0.56
0.12
0.19
0.12
0.26
0.11
0.67
0.07
0.13
0.3
0.5
0.2
0.3
0.7
1.0
0.1
0.1
82
BC RR
0.20
0.19
0.27
0.33
0.27
0.29
0.23
0.30
0.14
0.09
0.14
0.05
0.2
0.1
0.3
0.1
64
LCO
0.08
0.08
0.10
0.09
0.09
0.10
0.10
0.09
0.08
0.07
0.06
0.05
0.1
0.0
0.1
0.1
61
AC
0.43
0.55
0.20
0.47
0.21
0.38
0.12
0.15
0.09
0.09
0.08
0.08
0.2
0.2
0.5
0.1
92
DP
0.30
0.31
0.22
0.41
0.18
0.18
0.12
0.15
0.09
0.10
0.10
0.08
0.2
0.1
0.4
0.1
BBT
0.31
0.30
0.22
0.22
0.16
0.16
0.10
0.14
0.09
0.08
0.09
0.06
0.2
0.1
0.3
0.1
71
IC
3.92
5.17
0.24
0.32
0.17
0.18
0.11
0.15
0.09
0.09
0.10
0.07
0.9
1.7
5.2
0.1
85
70
84
NCF6 B210 NCF117
18.75 0.09
0.21
23.35 0.11
0.62
3.97
0.14
0.20
1.05
0.13
0.22
6.42
0.12
0.29
0.36
0.11
0.21
0.24
0.10
0.16
2.09
0.10
0.17
0.16
0.09
0.13
0.11
0.07
0.11
0.22
0.07
0.11
0.07
0.05
0.07
4.7
0.1
0.2
7.6
0.0
0.1
23.3
0.1
0.6
0.1
0.0
0.1
63
GCO
0.28
0.32
0.17
0.24
0.23
0.17
0.13
0.15
0.11
0.10
0.09
0.07
0.2
0.1
0.3
0.1
62
SR
0.13
0.20
0.49
0.17
0.13
0.10
0.09
0.09
0.07
0.07
0.06
0.05
0.1
0.1
0.5
0.0
66
BRN
0.12
0.11
0.19
0.15
0.16
0.16
0.16
0.16
0.09
0.11
0.09
0.08
0.1
0.0
0.2
0.1
67
68
HAM CO L
0.20
0.16
0.21
0.58
0.18
0.12
0.20
0.14
0.20
0.10
0.20
0.12
0.16
0.10
0.17
0.10
0.06
0.09
0.12
0.08
0.12
0.06
0.08
0.05
0.2
0.1
0.0
0.1
0.2
0.6
0.1
0.1
All station
mean
11.5
11.2
6.5
8.6
6.1
6.1
3.5
5.8
2.7
2.6
3.0
1.5
Table 2.4 pH at the Lower Cape Fear River stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
std de v
max
min
72
NAV
7.3
7.4
7.2
7.1
7.6
7.8
7.5
7.2
6.4
6.6
6.1
6.5
7.2
0.5
7.8
6.1
73
HB
7.5
7.3
7.1
7.1
7.3
7.9
7.4
7.2
6.3
6.9
6.2
6.5
7.2
0.5
7.9
6.2
75
BRR
7.5
7.4
7.2
7.2
7.5
8.0
7.1
6.8
6.8
7.6
6.3
6.6
7.2
0.5
8.0
6.3
86
M61
7.8
7.5
7.1
7.2
7.4
7.9
7.5
7.1
6.8
7.6
6.7
6.4
7.3
0.4
7.9
6.4
87
M54
8.0
7.7
7.4
7.5
7.5
8.0
7.4
8.1
7.3
8.0
7.1
6.5
7.5
0.4
8.1
6.5
88
M42
8.2
7.9
7.5
7.6
7.8
8.0
7.6
8.2
6.5
8.1
7.1
6.6
7.7
0.6
8.2
6.5
89
M35
8.1
8.0
7.7
7.7
7.9
8.0
7.9
8.1
8.3
8.0
7.3
6.8
8.0
0.4
8.3
6.8
90
M23
8.1
8.0
7.9
7.9
8.1
7.9
8.2
8.0
8.1
8.1
7.6
7.5
8.0
0.2
8.2
7.5
91
M18
8.2
8.0
8.0
7.9
8.0
7.9
7.7
7.9
8.1
7.9
7.8
7.9
7.9
0.1
8.2
7.7
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
std de v
max
min
69
ANC
6.1
6.2
5.8
5.8
6.0
5.5
10.3
6.6
5.9
4.6
5.9
4.5
5.9
1.4
10.3
4.5
79
SAR
6.7
6.3
5.7
6.5
6.4
5.9
6.3
6.3
6.5
6.5
6.5
6.3
6.4
0.3
6.7
5.7
78
GS
6.7
6.0
5.7
6.4
6.5
6.0
6.5
6.3
6.4
6.7
6.7
6.4
6.4
0.3
6.7
5.7
94
NC403
6.3
6.4
6.1
6.3
6.8
6.1
6.3
6.7
6.4
6.3
6.4
6.0
6.3
0.2
6.8
6.0
77
PB
6.4
7.2
6.2
6.9
6.4
6.0
6.9
6.3
6.3
6.6
6.7
6.5
6.5
0.3
7.2
6.0
80
LRC
9.6
7.8
6.4
7.4
7.1
6.6
6.4
6.7
6.5
6.7
7.2
6.6
6.7
0.9
9.6
6.4
81
83
82
RO C BC117 BCRR
8.0
8.5
7.5
7.5
7.6
6.4
6.8
6.8
6.9
7.1
7.5
7.4
7.0
7.1
6.1
6.6
6.8
6.8
6.3
7.3
5.8
6.8
6.5
6.3
6.5
6.3
6.7
6.6
6.4
6.5
7.2
7.5
7.2
6.2
6.5
5.6
6.8
7.0
6.6
0.5
0.6
0.6
8.0
8.5
7.5
6.2
6.3
5.6
93
SPD
8.2
7.7
7.6
7.5
7.7
7.6
7.4
7.6
7.4
7.8
7.6
7.4
7.6
0.2
8.2
7.4
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
std de v
max
min
59
74
NC11 LVC
6.9
7.1
6.6
6.9
5.9
6.0
6.4
6.5
5.9
6.6
6.1
6.5
6.4
6.3
5.7
6.5
7.1
6.7
5.5
6.0
6.2
7.0
6.5
6.8
6.3
6.6
0.5
0.3
7.1
7.1
5.5
6.0
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
std de v
max
min
65
6RC
7.3
6.4
6.4
6.4
6.1
5.9
5.9
7.3
6.2
6.1
7.4
6.4
6.4
0.5
7.4
5.9
64
LCO
6.9
6.5
5.7
6.5
5.9
5.8
5.6
6.3
5.9
5.9
7.3
5.7
5.9
0.5
7.3
5.6
61
AC
7.3
7.1
6.4
6.9
6.6
6.9
6.4
6.6
6.6
6.1
6.2
6.6
6.6
0.3
7.3
6.1
92
DP
7.1
6.9
6.5
6.8
6.6
6.5
6.5
6.8
6.5
6.2
6.1
6.6
6.6
0.3
7.1
6.1
BBT
7.1
6.9
6.5
6.5
6.5
6.4
6.4
6.8
6.3
6.2
5.8
6.2
6.5
0.3
7.1
5.8
63
GCO
6.9
6.8
6.1
6.6
6.2
5.8
5.9
6.7
5.9
5.9
6.9
6.2
6.2
0.4
6.9
5.8
62
SR
6.6
6.8
5.4
6.0
5.9
5.5
5.9
6.5
5.6
5.6
6.9
6.0
6.0
0.5
6.9
5.4
66
BRN
7.1
7.0
6.7
6.7
6.1
6.1
6.2
6.7
5.9
6.0
6.8
6.5
6.6
0.4
7.1
5.9
71
IC
7.1
6.9
6.5
6.7
6.4
6.5
6.5
6.8
6.4
6.3
5.8
6.4
6.5
0.3
7.1
5.8
85
70
84
NCF6 B210 NCF117
7.4
6.7
6.6
7.0
6.7
6.8
6.6
5.9
6.2
6.6
6.3
6.3
6.7
6.5
6.4
6.6
6.1
6.1
6.4
6.0
6.1
6.7
6.1
6.1
6.3
6.1
6.4
6.2
5.5
5.6
6.0
6.9
7.0
5.9
5.4
6.1
6.6
6.1
6.3
0.4
0.4
0.4
7.4
6.9
7.0
5.9
5.4
5.6
67
68
HAM CO L
6.8
5.2
6.9
6.6
6.8
3.7
6.6
3.5
6.3
3.5
6.2
3.5
6.3
3.6
6.8
4.1
5.7
3.7
6.2
3.3
6.6
4.5
6.5
4.1
6.6
3.7
0.3
0.9
6.9
6.6
5.7
3.3
All station
mean
7.3
7.1
6.5
6.8
6.7
6.6
6.7
6.8
6.5
6.5
6.7
6.3
Table 2.5 Dissolved Oxygen (mg/L) at the Lower Cape Fear River stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
72
NAV
4.4
3.7
4.7
3.4
8.2
10.7
12.1
11.7
10.8
8.6
6.0
5.8
7.5
3.1
12.1
3.4
73
HB
5.6
3.9
4.1
3.6
8.2
10.7
11.8
11.7
10.8
9.1
6.0
5.9
7.6
3.0
11.8
3.6
75
BRR
5.7
5.2
3.9
3.8
8.7
11.1
12.3
12.6
10.8
8.6
6.3
6.2
7.9
3.0
12.6
3.8
86
M61
6.2
4.2
3.7
4.2
8.1
10.6
12.1
11.3
10.6
8.2
6.0
5.5
7.6
2.9
12.1
3.7
87
M54
8.0
5.4
3.7
4.8
7.4
11.4
12.2
11.7
10.6
8.1
6.2
5.9
8.0
2.8
12.2
3.7
88
M42
8.2
7.3
4.2
5.4
7.4
11.4
12.4
11.6
10.9
8.3
6.6
5.8
8.3
2.6
12.4
4.2
89
M35
7.2
7.2
5.3
5.8
7.5
10.2
11.4
11.2
10.6
8.7
6.7
6.1
8.2
2.1
11.4
5.3
90
M23
6.5
6.2
5.6
6.0
7.7
10.8
11.8
10.5
10.9
9.6
7.5
7.1
8.4
2.1
11.8
5.6
91
M18
6.5
6.0
5.8
6.1
7.5
10.4
10.2
10.3
10.5
9.3
7.5
7.4
8.1
1.8
10.5
5.8
DWQ# 69
month ANC
0.4
JUL
0.6
AUG
0.3
SEP
O CT 0.7
0.6
NO V
4.0
DEC
9.2
JAN
8.9
FEB
MAR 10.7
7.6
APR
5.3
MAY
4.0
JUN
mean 4.4
std de v 3.8
10.7
max
0.3
min
79
SAR
4.5
4.2
4.0
6.5
9.3
11.8
11.3
11.3
10
6.9
4.1
5.0
7.4
3.0
11.8
4.0
78
94
77
GS NC403 PB
2.2
1.0
1.8
1.1
0.8
2.8
2.5
0.1
3.2
0.7
0.9
16.0
4.6
3.6
6.6
10.7
8.6
7.6
11.4
7.3
9.6
11.5
5.6
8.6
8.6
7.3
9.8
9.7
4.3
8.4
5.0
0.4
7.0
5.6
0.8
8.4
6.1
3.4
7.5
3.9
3.0
3.6
11.5
8.6
16.0
0.7
0.1
1.8
80
LRC
16.8
9.5
6.9
9.5
10.9
12.2
12.4
12.3
11.2
9.4
8.5
7.7
10.6
2.5
16.8
6.9
81
83
82
RO C BC117 BCRR
6.9
14.4
2.2
5.9
4.1
0.7
5.4
5.4
5.0
3.7
6.8
1.1
9.3
7.0
2.4
11.2
9.8
8.5
11.7
10.3
11.1
11.9
9.2
9.5
9.7
9.4
9.6
8.2
8.4
8.2
6.1
4.4
2.2
5.5
7.9
7.7
8.0
8.1
5.7
2.7
2.7
3.6
11.9
14.4
11.1
3.7
4.1
0.7
93
SPD
5.8
4.9
4.4
4.5
6.9
10.4
11.3
11.0
10.5
8.7
6.6
6.6
7.6
2.5
11.3
4.4
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
59
74
NC11 LVC
7.7
7.4
6.3
4.5
7.0
4.2
5.6
5.6
10.1
9.8
11.2
10.6
11.8
8.3
13.0
12.7
11.7
11.4
8.9
7.0
7.7
6.9
7.1
6.8
9.0
7.9
2.4
2.6
13.0
12.7
5.6
4.2
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
65
6RC
4.8
6.2
5.4
6.6
9.4
11.9
12.2
11.6
9.3
8.5
7.0
5.5
8.2
2.6
12.2
4.8
64
LCO
4.3
6.1
6.1
6.7
9.6
12.1
11.7
11.6
8.4
8.4
7.2
5.5
8.1
2.5
12.1
4.3
61
AC
7.2
4.4
6.3
6.3
9.9
10.4
11.5
12.9
11.5
8.6
7.1
6.9
8.6
2.5
12.9
4.4
92
DP
4.4
4.1
5.7
3.3
9.5
9.9
11.6
12.9
11.5
8.4
6.1
6.6
7.8
3.1
12.9
3.3
BBT
4.3
4.3
4.4
3.3
9.0
10.0
10.7
12.5
10.0
6.4
5.6
5.3
7.2
3.0
12.5
3.3
71
IC
4.6
4.1
5.0
3.3
8.5
9.7
11.0
12.8
10.8
7.3
5.8
5.8
7.4
3.0
12.8
3.3
85
70
84
NCF6 B210 NCF117
6.6
5.5
5.1
4.6
2.9
5.7
4.8
4.7
4.3
4.5
4.3
3.5
7.5
8.1
6.2
8.6
10.6
8.6
10.0
11.1
9.8
11.6
11.2
11.7
8.9
9.5
8.7
5.7
6.9
5.4
5.5
5.4
4.7
4.4
6.0
4.5
6.9
7.2
6.5
2.3
2.7
2.5
11.6
11.2
11.7
4.4
2.9
3.5
63
GCO
2.6
4.5
0.8
4.9
8.4
10.4
10.7
9.1
6.9
5.7
4.7
4.6
6.1
2.9
10.7
0.8
62
SR
1.2
5.7
2.9
0.4
7.7
8.2
11.1
9.6
8.1
7.3
3.1
4.3
5.8
3.3
11.1
0.4
66
BRN
6.1
9.0
8.4
8.4
9.6
11.9
12.2
11.8
8.2
8.6
8.1
7.0
9.1
1.9
12.2
6.1
67
68
HAM CO L
1.4
5.0
6.6
4.3
3.3
5.5
3.3
6.2
7.7
7.9
9.1
10.4
10.8
11.2
11.1
10.3
9.1
8.1
8.1
6.5
4.9
7.0
6.4
5.7
6.8
7.3
3.0
2.2
11.1
11.2
1.4
4.3
All station
mean
5.5
4.8
4.5
4.8
7.7
10.2
11.1
11.1
9.9
7.9
5.9
5.9
Table 2.6 Turbidity (NTU) at the Lower Cape Fear River stations, 2002-2003.
DWQ# 72
month NAV
18
JUL
17
AUG
21
SEP
24
O CT
35
NO V
32
DEC
21
JAN
12
FEB
71
MAR
39
APR
21
MAY
24
JUN
mean
28
std de v 15
71
max
12
min
73
HB
18
15
18
15
38
29
16
12
70
30
17
23
25
15
70
12
75
BRR
12
13
19
14
31
32
38
14
53
25
14
19
24
12
53
12
86
M61
7
9
10
10
20
36
47
13
65
25
22
14
23
17
65
7
87
M54
12
11
13
28
30
31
41
16
63
29
22
23
27
14
63
11
88
M42
12
10
11
16
25
22
36
16
55
34
14
19
23
13
55
10
89
M35
6
8
12
11
99
26
12
14
42
25
9
14
23
25
99
6
90
M23
4
5
7
6
17
17
10
14
25
17
9
9
12
6
25
4
91
M18
3
5
9
8
13
21
11
20
21
10
11
9
12
6
21
3
DWQ# 69
month ANC
4
JUL
4
AUG
6
SEP
5
O CT
9
NO V
4
DEC
3
JAN
3
FEB
13
MAR
6
APR
15
MAY
12
JUN
mean
7
std de v 4
15
max
3
min
79
SAR
2
3
4
2
2
2
2
3
3
6
6
6
3
2
6
2
78
GS
11
6
3
35
3
2
1
4
140
3
4
3
18
38
140
1
94
NC403
6
3
2
4
2
1
1
1
0
0
7
2
2
2
7
0
77
PB
25
18
5
34
11
3
3
4
2
2
8
3
10
10
34
2
80
LRC
3
2
14
2
4
11
2
4
7
4
4
26
7
7
26
2
81
83
82
RO C BC117 BCRR
2
4
19
2
3
11
12
9
11
4
3
9
4
6
16
5
16
8
2
6
52
4
81
11
10
15
12
8
8
9
8
10
12
9
19
13
6
15
15
3
21
11
12
81
52
2
3
8
93
SPD
8
15
15
13
17
18
9
11
28
11
18
8
14
5
28
8
DWQ# 59
74
month NC11 LVC
8
9
JUL
10
10
AUG
29
4
SEP
9
9
O CT
20
20
NO V
12
11
DEC
46
5
JAN
18
20
FEB
86
82
MAR
36
19
APR
18
20
MAY
30
21
JUN
me an
27
19
20
std de v 21
86
82
max
8
4
min
DWQ# 65
month 6RC
5
JUL
4
AUG
17
SEP
4
O CT
4
NO V
3
DEC
4
JAN
5
FEB
6
MAR
8
APR
5
MAY
3
JUN
me an
6
std de v 4
17
max
3
min
64
LCO
15
2
6
2
4
3
5
3
3
4
6
1
5
4
15
1
61
AC
10
11
28
12
17
18
41
19
87
38
12
32
27
21
87
10
92
DP
16
7
19
12
14
13
38
15
96
35
13
30
26
23
96
7
BBT
11
6
11
5
16
11
15
11
42
15
10
11
14
9
42
5
63
GCO
4
4
20
15
2
1
3
2
1
2
4
1
5
6
20
1
62
SR
15
4
13
25
2
1
3
38
1
2
2
2
9
11
38
1
66
BRN
12
3
3
2
4
3
5
3
85
7
7
8
12
22
85
2
71
IC
21
18
14
7
20
17
23
11
70
25
12
18
21
15
70
7
85
70
84
NCF6 B210 NCF117
8
3
4
15
1
4
31
2
4
10
2
1
24
2
2
38
2
4
13
6
4
15
3
4
10
3
5
5
2
3
23
3
3
5
2
3
16
3
3
10
1
1
38
6
5
5
1
1
67
68
HAM CO L
10
4
8
9
4
7
4
1
8
3
4
1
6
1
4
1
125
2
7
1
14
2
9
1
17
3
33
3
125
9
4
1
All station
mean
9
8
12
10
16
13
15
12
40
14
11
12
Table 2.8 Light Attenuation (k) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period.
DWQ #
59
month NC11
JUL
1.79
AUG
1.80
SEP
3.05
OCT
2.03
NOV
2.37
DEC
JAN
FEB
MAR
APR
3.55
MAY
2.82
JUN
mean
2.49
std dev 0.63
max
3.55
min
1.79
61
AC
2.91
2.91
3.61
3.19
2.29
92
DP
2.57
2.19
2.60
3.21
2.25
71
IC
2.81
2.82
2.50
3.33
2.79
72
NAV
2.55
2.29
3.35
4.39
3.23
73
HB
2.76
3.04
3.17
2.93
3.16
75
BRR
2.18
2.34
2.97
2.87
3.26
86
M61
1.60
1.51
2.26
2.07
2.85
87
M54
2.47
1.81
2.73
2.53
3.15
88
M42
2.10
1.38
2.46
2.57
2.78
89
M35
nd
1.79
1.92
2.04
nd
90
M23
1.09
0.96
1.47
1.31
1.72
91
M18
0.66
1.16
1.78
1.35
1.54
93
SPD
1.42
2.26
2.49
2.39
2.17
85
NCF6
1.90
2.20
4.72
3.66
2.95
BBT
2.20
2.17
2.56
3.42
2.54
3.56
2.36
3.81
3.08
0.53
3.81
2.29
3.45
2.90
3.64
2.85
0.51
3.64
2.19
3.25
2.82
3.54
2.98
0.33
3.54
2.50
3.43
3.38
3.62
3.28
0.60
4.39
2.29
3.72
4.36
3.48
3.33
0.48
4.36
2.76
3.34
3.13
3.76
3.57
3.72
2.67
0.88
3.76
1.51
4.11
3.14
3.70
2.96
0.68
4.11
1.81
4.35
2.89
3.37
2.74
0.82
4.35
1.38
3.27
2.64
3.21
2.48
0.60
3.27
1.79
2.59
2.14
2.37
1.71
0.57
2.59
0.96
1.66
2.22
1.69
1.51
0.43
2.22
0.66
2.58
2.98
2.40
2.34
0.41
2.98
1.42
3.91
5.63
4.63
3.70
1.21
5.63
1.90
3.16
3.23
3.32
2.83
0.48
3.42
2.17
2.87
0.42
3.34
2.18
All stations
mean
2.1
2.0
2.7
2.7
2.6
3.4
3.1
3.3
Table 2.9 Total Nitrogen (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
72
NAV
1,330
1,160
2,250
1,880
1,590
1,200
970
1,280
1,180
1,060
960
970
1,319
382
2,250
960
73
HB
1,280
1,110
1,800
1,640
1,560
1,060
900
1,310
1,010
920
830
1,090
1,209
300
1,800
830
75
BRR
1,240
1,000
1,900
1,640
1,530
1,070
980
1,290
1,000
1,670
1,010
980
1,276
314
1,900
980
86
M61
1,060
930
1,740
1,400
1,470
1,060
1,020
1,200
810
1,380
1,210
1,060
1,195
250
1,740
810
87
M54
980
1,640
2,200
1,400
1,480
980
1,040
1,160
1,160
1,110
1,120
1,190
1,288
336
2,200
980
88
M42
980
1,000
1,460
860
1,300
900
1,050
960
1,130
910
1,050
1,130
1,061
167
1,460
860
89
M35
1,020
430
1,530
730
1,240
720
850
780
1,070
930
970
870
928
266
1,530
430
90
M23
410
670
1,400
1,030
810
560
760
510
820
750
720
760
767
245
1,400
410
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
69
ANC
1,110
1,120
1,810
1,230
1,170
1,220
2,920
1,170
2,230
1,580
1,460
2,590
1,634
598
2,920
1,110
79
SAR
2,720
2,720
1,630
1,320
900
2,150
740
1,150
1,240
1,250
1,160
1,200
1,515
635
2,720
740
78
GS
1,290
1,260
1,440
1,680
1,020
1,120
550
660
1,580
1,400
990
900
1,158
335
1,680
550
94
NC403
1,050
1,260
1,380
1,080
830
1,400
1,380
1,540
1,730
1,750
1,540
660
1,300
325
1,750
660
77
PB
1,940
1,480
2,440
1,700
920
1,460
1,580
1,160
2,210
1,590
990
1,240
1,559
445
2,440
920
80
LRC
680
740
1,350
750
920
970
870
1,010
1,410
1,090
670
1,220
973
242
1,410
670
81
RO C
1,630
1,360
4,350
1,840
5,440
2,410
1,440
1,010
1,680
1,250
1,160
1,380
2,079
1,325
5,440
1,010
83
BC117
14,500
16,920
4,930
17,900
13,640
5,390
4,870
6,000
2,350
3,180
16,700
4,410
9,233
5,825
17,900
2,350
91
93
M18 SPD
320
490
350
790
1,050 1,240
910 1,090
590
630
430
510
270
580
470
550
760
870
90
880
620
550
630
740
541
743
264
230
1,050 1,240
90
490
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
59
NC11
1,600
1,470
2,330
2,310
1,660
1,230
1,270
1,290
1,080
980
1,170
990
1,448
441
2,330
980
74
LVC
1,690
2,170
1,610
2,050
1,820
1,150
630
1,410
1,210
1,250
2,590
1,150
1,561
517
2,590
630
61
AC
2,000
2,410
2,300
2,280
1,760
1,920
1,310
1,450
1,140
1,000
1,190
1,370
1,678
476
2,410
1,000
92
DP
1,520
1,370
2,510
2,130
1,590
990
1,350
1,440
1,140
1,040
1,260
1,040
1,448
438
2,510
990
71
IC
1,500
1,360
2,330
2,020
1,380
1,120
1,150
1,310
1,050
790
1,090
1,010
1,343
420
2,330
790
85
NCF6
1,130
1,050
1,690
670
1,320
1,290
1,070
1,050
1,080
1,140
1,330
1,240
1,172
230
1,690
670
70
B210
720
700
1,780
690
730
870
630
790
800
830
1,030
1,170
895
304
1,780
630
82
BCRR
1,760
1,360
1,610
990
840
740
880
230
1,240
470
810
1,000
994
424
1,760
230
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
65
6RC
990
610
2,090
1,070
790
920
990
890
1,140
1,280
1,230
1,090
1,091
350
2,090
610
64
LCO
830
890
1,500
910
680
760
980
1,300
990
1,170
1,160
1,040
1,018
224
1,500
680
63
GCO
1,480
1,250
2,140
1,340
1,050
1,060
850
1,370
870
960
990
820
1,182
357
2,140
820
62
66
67
68
SR
BRN HAM CO L
940
850
780 1,040
1,090 480
720 1,940
1,920 1,300 1,530 1,590
3,420 510
780
990
1,280 550
590
790
650
430
610
970
540
500
740
750
550
450
390
620
480 1,350 1,790 690
790
650
880
930
1,220 680
990 1,220
980
840 1,140 1,650
1,155 716
912 1,098
786
304
385
402
3,420 1,350 1,790 1,940
480
430
390
620
84
NCF117
820
730
1,590
740
910
1,210
1,210
980
1,370
1,170
1,130
1,450
1,109
268
1,590
730
All station
mean
1,601
1,664
1,927
1,871
1,626
1,191
1,054
1,134
1,195
1,109
1,574
1,170
Table 2.10 Nitrate-Nitrite (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
72
NAV
600
460
760
890
890
340
50
780
430
360
280
320
513
257
890
50
73
HB
440
410
800
720
810
320
440
740
390
370
250
340
503
195
810
250
75
BRR
400
300
880
590
760
340
440
710
360
400
340
330
488
188
880
300
86
M61
300
320
720
510
630
340
420
600
180
380
400
310
426
152
720
180
87
M54
220
1,000
640
490
590
310
440
570
350
390
380
340
477
198
1,000
220
88
M42
60
150
490
350
490
260
440
460
360
310
340
340
338
126
490
60
89
M35
20
80
420
270
450
190
390
310
400
310
340
330
293
128
450
20
90
M23
5
30
210
150
220
140
360
80
210
260
210
300
181
101
360
5
91
M18
20
5
160
100
190
90
80
10
260
90
170
220
116
80
260
5
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
69
ANC
5
5
5
5
5
5
900
60
950
110
5
50
175
337
950
5
79
SAR
1,450
1,540
5
200
140
1,370
210
550
530
160
40
270
539
552
1,540
5
78
GS
20
5
5
5
5
5
5
5
310
5
5
190
47
94
310
5
94
NC403
20
5
5
5
260
780
900
1,150
1,260
310
5
50
396
467
1,260
5
77
PB
20
5
970
5
90
630
1,250
730
1,760
780
5
590
570
548
1,760
5
80
LRC
30
40
5
50
290
220
460
340
910
190
30
400
247
251
910
5
81
RO C
640
580
2,810
570
4,530
1,360
900
510
890
290
180
430
1,141
1,221
4,530
180
83
BC117
13,700
16,000
3,330
16,800
12,500
4,430
4,440
5,020
1,580
2,350
15,600
3,190
8,245
5,799
16,800
1,580
82
BCRR
5
20
150
5
200
290
610
5
560
100
5
220
181
204
610
5
93
SPD
5
230
50
40
120
90
260
140
250
200
40
270
141
93
270
5
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
59
NC11
680
660
960
1,580
900
690
650
960
370
390
480
310
719
336
1,580
310
74
61
92
LVC
AC
DP
740
690
680
1,190 1,130 620
260
710
820
1,450 1,340 1,400
920
930
860
620
590
390
120
650
660
890
930
950
360
380
370
420
420
470
310
440
370
240
330
330
627
712
660
400
303
301
1,450 1,340 1,400
120
330
330
BBT
779
746
660
702
964
343
402
800
424
296
400
288
567
222
964
288
71
85
70
84
IC
NCF6 B210 NCF117
66
370
70
170
520
350
60
60
910
70
150
50
1,210
80
30
20
780
510
50
30
380
210
60
400
570
280
200
450
850
320
380
390
340
350
310
520
290
190
60
150
320
140
70
180
280
240
110
290
543
259
129
226
317
124
108
170
1,210 510
380
520
66
70
30
20
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
65
6RC
340
50
5
300
200
360
480
530
570
550
320
280
332
177
570
5
64
LCO
40
30
5
10
80
200
470
880
510
320
150
90
232
257
880
5
66
BRN
60
60
60
100
90
90
80
150
260
230
70
50
108
66
260
50
67
68
HAM CO L
20
10
5
910
30
30
5
10
60
20
5
5
150
5
5
5
200
5
140
5
110
5
100
5
69
85
66
249
200
910
5
5
63
GCO
260
220
5
5
280
470
300
980
360
40
30
10
247
269
980
5
62
SR
20
5
40
5
100
50
50
120
50
60
90
70
55
34
120
5
All station
mean
677
828
497
882
880
486
532
638
483
331
661
338
Table 2.11 Ammonium (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std dev
max
min
72
NAV
170
50
140
60
100
130
70
70
30
60
110
70
88
40
170
30
73
HB
170
40
120
80
100
110
80
90
60
70
100
70
91
32
170
40
75
BRR
130
40
120
80
130
150
100
80
50
80
100
80
95
32
150
40
86
M61
150
60
120
130
170
190
100
120
70
60
180
90
120
44
190
60
87
M54
80
80
160
60
200
180
140
170
90
70
160
110
125
47
200
60
88
M42
40
40
80
60
190
170
150
140
70
80
170
100
108
51
190
40
89
M35
40
40
70
70
180
130
110
100
90
80
150
100
97
40
180
40
90
M23
20
40
60
70
130
80
110
40
30
80
110
90
72
33
130
20
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std dev
max
min
69
ANC
80
90
10
100
80
50
320
60
50
140
160
1,020
180
264
1,020
10
79
SAR
100
80
80
110
250
90
40
80
20
70
80
80
90
54
250
20
78
GS
60
40
50
140
50
40
30
40
10
30
70
60
52
31
140
10
94
NC 403
100
170
90
50
80
80
40
70
20
30
210
60
83
54
210
20
77
PB
430
120
250
120
170
160
60
70
40
50
130
70
139
105
430
40
80
LRC
30
50
80
100
200
100
50
230
20
80
90
120
96
61
230
20
81
83
RO C BC 117
100
80
60
100
80
160
100
300
50
100
140
120
50
60
50
200
50
50
120
60
90
130
100
420
83
148
29
106
140
420
50
50
91
M18
60
40
70
110
130
60
30
40
30
30
90
60
63
31
130
30
82
BC RR
470
520
180
40
130
70
50
40
50
40
160
130
157
159
520
40
93
SPD
50
60
130
70
100
60
80
50
30
80
70
100
73
26
130
30
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std dev
max
min
59
74
NC 11 LVC
90
120
70
210
220
80
70
80
100
220
90
100
70
120
40
80
60
130
70
190
100 1,180
70
180
88
224
43
292
220 1,180
40
80
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std dev
max
min
65
6RC
160
80
140
60
60
80
60
40
60
60
70
80
79
34
160
40
64
LCO
160
70
110
190
40
50
40
70
10
50
70
60
77
50
190
10
61
AC
440
330
330
320
130
350
90
70
70
80
100
80
199
135
440
70
92
DP
200
80
220
100
90
90
100
80
60
80
130
80
109
48
220
60
BBT
93
30
51
28
41
36
70
63
33
22
43
20
44
21
93
20
63
GC O
210
130
120
270
60
50
40
60
10
30
50
50
90
75
270
10
62
SR
220
40
160
50
60
40
30
40
10
30
40
60
65
59
220
10
66
BRN
100
60
70
120
70
50
40
40
80
60
90
70
71
23
120
40
71
IC
200
60
160
80
80
90
90
60
50
60
110
70
93
43
200
50
85
70
84
NC F6 B210 NC F117
280
180
220
50
60
50
40
90
60
40
200
40
160
40
40
60
40
50
60
40
70
120
50
60
50
10
30
60
50
80
60
40
90
80
60
90
88
72
73
67
56
48
280
200
220
40
10
30
67
68
HAM C O L
160
280
80
210
170
190
80
70
50
40
40
30
50
60
40
40
110
10
80
40
100
40
90
60
88
89
41
83
170
280
40
10
All station
mean
158
97
125
106
110
96
70
78
47
65
133
92
Table 2.12 Total Kjeldahl Nitrogen (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
72
73
75
86
87
NAV
HB
BRR M61 M54
730
840
840
760
760
700
700
700
610
640
1,490 1,000 1,020 1,020 1,560
990
920 1,050 890
910
700
750
770
840
890
860
740
730
720
670
470
460
540
600
600
500
570
580
600
590
750
620
640
630
810
700
550 1,270 1,000 720
680
580
670
810
740
650
750
650
750
850
768
707
788
769
812
254
153
210
142
248
1,490 1,000 1,270 1,020 1,560
470
460
540
600
590
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
69
ANC
1,110
1,120
1,810
1,230
1,170
1,220
2,020
1,110
1,280
1,470
1,460
2,540
1,462
427
2,540
1,110
79
SAR
1,270
1,180
1,630
1,120
760
780
530
600
710
1,090
1,120
930
977
304
1,630
530
78
GS
1,270
1,260
1,440
1,680
1,020
1,120
550
660
1,270
1,400
990
710
1,114
328
1,680
550
94
NC403
1,030
1,260
1,380
1,080
570
620
480
390
470
1,440
1,540
610
906
409
1,540
390
88
M42
920
850
970
510
810
640
610
500
770
600
710
790
723
147
970
500
89
90
M35 M23
1,000 410
350
640
1,110 1,190
460
880
790
590
530
420
460
400
470
430
670
610
620
490
630
510
540
460
636
586
219
224
1,110 1,190
350
400
91
M18
300
350
890
810
400
340
190
460
500
50
450
410
429
223
890
50
77
80
81
83
82
PB
LRC RO C BC117 BCRR
1,920 650
990
840 1,760
1,480 700
780
920 1,340
1,470 1,350 1,540 1,600 1,460
1,700 700 1,270 1,130 990
830
630
910 1,140 640
830
750 1,050 960
450
330
410
540
430
270
430
670
500
980
230
450
500
790
770
680
810
900
960
830
370
990
640
980 1,130 810
650
820
950 1,220 780
991
727
938
996
815
507
225
272
274
469
1,920 1,350 1,540 1,600 1,760
330
410
500
430
230
93
SPD
490
560
1,190
1,050
510
420
320
410
620
680
510
470
603
250
1,190
320
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
59
NC11
920
810
1,370
730
760
540
620
330
710
590
690
680
729
239
1,370
330
74
LVC
950
980
1,350
600
900
530
510
520
850
830
2,280
910
934
468
2,280
510
61
92
71
AC
DP
IC
1,310 840
840
1,280 750
840
1,590 1,690 1,420
940
730
810
830
730
600
1,330 600
740
660
690
580
520
490
460
760
770
710
580
570
500
750
890
770
1,040 710
730
966
788
750
328
292
236
1,590 1,690 1,420
520
490
460
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
65
6RC
650
560
2,090
770
590
560
510
360
570
730
910
810
759
426
2,090
360
64
LCO
790
860
1,500
900
600
560
510
420
480
850
1,010
950
786
289
1,500
420
63
GCO
1,220
1,030
2,140
1,340
770
590
550
390
510
920
960
810
936
456
2,140
390
85
NCF6
760
700
1,620
590
810
1,080
790
730
730
950
1,190
1,000
913
271
1,620
590
70
B210
650
640
1,630
670
680
810
430
410
490
770
960
1,060
767
321
1,630
410
62
66
67
68
SR
BRN HAM CO L
920
790
760 1,030
1,090 420
720 1,030
1,880 1,240 1,500 1,560
3,420 410
780
980
1,180 460
530
770
600
340
610
970
490
420
590
750
430
300
390
620
430 1,090 1,590 690
730
420
740
930
1,130 610
880 1,220
910
790 1,040 1,650
1,101 608
844 1,017
802
293
352
309
3,420 1,240 1,590 1,650
430
300
390
620
84
NCF117
650
670
1,540
720
880
810
760
590
850
1,020
950
1,160
883
253
1,540
590
All station
mean
910
834
1,436
986
748
701
518
501
711
778
907
831
Table 2.13 Total Phosphorus (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
72
NAV
130
140
200
180
160
120
70
110
60
80
120
100
123
41
200
60
73
HB
110
100
170
120
160
100
60
110
140
80
100
110
113
30
170
60
75
BRR
70
250
170
120
150
100
80
120
110
90
110
100
123
47
250
70
86
M61
80
80
130
90
120
110
120
90
100
80
130
110
103
18
130
80
87
M54
70
80
110
90
110
110
120
90
130
100
110
130
104
18
130
70
88
M42
80
110
90
80
90
90
110
70
140
100
90
110
97
18
140
70
89
M35
30
50
70
60
100
80
60
60
110
90
70
100
73
22
110
30
90
M23
30
140
50
40
40
60
50
40
80
60
50
80
60
28
140
30
91
M18
20
20
30
30
40
50
10
30
60
40
50
60
37
15
60
10
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
69
ANC
100
100
140
110
60
90
220
60
120
110
150
300
130
66
300
60
79
SAR
70
170
140
360
120
60
40
60
40
100
180
100
120
85
360
40
78
GS
230
190
110
460
60
60
20
30
60
70
150
90
128
117
460
20
94
NC403
380
1,570
740
600
60
80
60
50
70
110
1,460
150
444
527
1,570
50
77
PB
320
480
300
370
120
130
40
50
40
60
210
80
183
144
480
40
80
LRC
50
50
70
60
40
50
40
30
20
40
60
70
48
15
70
20
81
RO C
670
1,200
1,030
550
1,400
230
90
170
90
210
370
140
513
443
1,400
90
83
BC117
4,740
3,610
570
2,270
2,600
430
350
890
140
420
2,560
180
1,563
1,480
4,740
140
82
BCRR
290
330
280
410
150
130
40
50
150
30
140
70
173
120
410
30
93
SPD
40
40
50
50
50
40
10
40
60
50
30
60
43
13
60
10
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
59
74
NC11 LVC
250
190
210
290
210
30
230
220
130
160
90
70
100
20
100
120
340
170
100
90
110
240
110
110
165
143
77
81
340
290
90
20
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
65
6RC
130
240
310
170
70
90
30
40
140
60
150
80
126
80
310
30
64
LCO
120
90
70
60
30
20
10
20
20
40
90
40
51
34
120
10
61
AC
280
310
180
270
140
110
110
110
160
120
110
110
168
73
310
110
92
DP
190
180
190
230
130
80
110
110
150
100
120
120
143
43
230
80
63
62
GCO
SR
570
140
810
90
1,400 1,000
470
350
130
70
90
20
90
10
230
20
110
30
140
70
260
110
170
70
373
165
378
266
1,400 1,000
90
10
71
IC
170
170
200
200
150
80
90
100
130
80
120
100
133
43
200
80
85
70
84
NCF6 B210 NCF117
50
110
110
70
120
80
70
80
50
80
150
60
120
70
70
140
30
70
60
20
40
70
20
50
140
30
50
90
50
90
130
90
90
120
70
110
95
70
73
31
40
23
140
150
110
50
20
40
66
BRN
110
70
60
600
40
40
30
30
140
80
120
100
118
149
600
30
67
68
HAM CO L
240
40
230
40
190
30
230
10
110
20
80
20
50
10
80
10
290
20
90
20
200
180
130
20
160
35
76
45
290
180
50
10
All station
mean
312
358
256
284
214
92
65
97
108
92
250
100
Table 2.14 Orthophosphate (g/L) at the Lower Cape Fear River Program stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
72
NAV
80
70
120
100
90
40
30
60
40
30
60
40
63
28
120
30
73
HB
50
60
110
80
90
30
30
70
40
30
70
40
58
25
110
30
75
BRR
40
40
120
70
80
30
30
60
40
30
70
40
54
26
120
30
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
69
ANC
70
20
70
60
10
40
50
20
90
90
100
320
78
78
320
10
79
SAR
630
70
70
170
90
40
20
30
20
40
110
60
113
161
630
20
78
GS
80
50
60
80
30
30
10
10
20
30
80
40
43
25
80
10
86
M61
40
50
90
60
60
40
40
60
30
30
60
50
51
16
90
30
87
M54
30
40
80
70
60
30
40
40
40
30
50
50
47
15
80
30
88
M42
20
30
50
50
50
40
40
30
30
30
50
50
39
10
50
20
89
M35
20
20
50
40
40
30
30
10
30
30
50
40
33
12
50
10
90
M23
10
10
30
30
30
20
30
0
20
30
30
30
23
10
30
0
91
M18
0
10
30
20
20
10
10
0
20
10
30
10
14
10
30
0
94
77
NC403 PB
80
30
250
110
480
80
290
30
50
40
60
60
50
40
30
20
60
20
90
30
230
90
40
50
143
50
134
28
480
110
30
20
80
LRC
0
20
10
30
20
20
10
0
10
10
30
20
15
10
30
0
81
RO C
740
1,340
900
420
1,340
110
70
120
50
90
220
90
458
475
1,340
50
83
BC117
3,740
3,400
290
2,370
2,530
430
350
820
110
310
2,440
120
1,409
1,319
3,740
110
82
BCRR
80
120
210
180
90
110
40
10
100
10
40
30
85
61
210
10
93
SPD
10
10
20
20
20
10
10
0
20
20
20
20
15
6
20
0
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
59
74
NC11 LVC
190
180
130
220
110
10
170
180
90
110
50
50
60
10
60
70
40
50
30
30
60
140
40
50
86
92
51
69
190
220
30
10
DWQ# 65
month 6RC
50
JUL
70
AUG
100
SEP
70
O CT
30
NO V
40
DEC
20
JAN
10
FEB
20
MAR
20
APR
50
MAY
40
JUN
me an
43
std dev 25
100
max
10
min
64
LCO
50
40
20
70
10
10
10
0
10
10
30
20
23
20
70
0
61
AC
200
270
110
210
100
60
50
70
50
30
60
50
105
75
270
30
92
DP
160
140
100
190
90
40
60
80
40
30
60
40
86
50
190
30
BBT
120
110
100
110
90
30
30
60
40
20
60
40
68
35
120
20
63
GCO
330
300
380
230
100
70
80
180
90
120
150
30
172
109
380
30
62
SR
30
10
10
50
30
10
0
0
10
10
40
20
18
15
50
0
66
BRN
20
20
20
30
10
10
10
0
20
20
40
40
20
12
40
0
71
IC
120
90
130
170
90
30
50
70
40
30
60
40
77
43
170
30
85
70
84
NCF6 B210 NCF117
40
50
60
50
30
40
20
50
80
40
70
20
30
40
20
30
20
10
20
20
10
30
30
10
30
50
30
50
40
60
60
70
30
80
43
33
41
16
22
18
70
80
80
20
10
20
67
68
HAM CO L
70
20
50
10
60
10
70
0
40
0
30
0
30
0
10
0
70
10
30
0
70
10
60
0
49
5
20
6
70
20
10
0
All station
mean
312
358
256
284
214
92
65
97
108
92
250
100
Table 2.15 Aluminum (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. There is no North
Carolina standard for Aluminum.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
149
203
329
365
228
1,070
391
313
1070
149
87
M54
75
110
232
628
353
1,260
443
408
1260
75
89
M35
34
91
309
550
306
485
296
188
550
34
90
M23
44
90
255
594
325
560
311
210
594
44
91
M18
67
67
220
634
203
245
239
190
634
67
59
NC11
232
342
722
580
1,450
1,360
781
469
1450
232
74
LVC
295
362
390
580
879
894
567
242
894
295
92
DP
223
431
418
495
1,540
1,420
755
521
1540
223
79
SAR
137
100
159
127
409
301
206
112
409
100
80
LRC
59
82
211
101
302
1,460
369
495
1460
59
83
84
BC117 NC F 117
160
278
151
299
505
349
208
338
362
538
1,080
734
411
423
324
163
1080
734
151
278
65
6RC
108
124
149
133
412
228
192
105
412
108
64
GCO
172
151
103
94
81
152
126
34
172
81
68
CO L
383
842
757
685
758
903
721
166
903
383
Table 2.16 Arsenic (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for arsenic is 50 g/L for freshwater and tidal salt water
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
0
0
0
0
0
0
0
0
0
89
M35
0
0
0
0
0
0
0
0
0
0
90
M23
0
0
0
12
0
0
2
4
12
0
91
M18
0
0
0
13
0
0
2
5
13
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.17 Cadmium (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for cadmium in freshwater is 2 mg/l and in tidal
salt water is 5 mg/l.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
0
0
0
0
0
0
0
0
0
89
M35
0
0
0
0
0
0
0
0
0
0
90
M23
0
0
0
0
0
0
0
0
0
0
91
M18
0
0
0
0
0
0
0
0
0
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.18 Chromium (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represent
a measurement below the analytical detection limit. The North Carolina standard for cadmium in freshwater is 50 mg/l and in tidal
salt water is 20 mg/l.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
0
0
0
0
0
0
0
0
0
89
M35
0
0
0
0
0
0
0
0
0
0
90
M23
0
0
0
0
0
0
0
0
0
0
91
M18
0
0
0
0
0
0
0
0
0
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.19 Copper (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for copper in freshwater is 7 g/l and in tidal
salt water is 3 g/l.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
14
7
11
3
3
6
5
14
0
87
M54
0
0
5
0
3
4
2
2
5
0
89
M35
6
0
8
8
4
5
5
3
8
0
90
M23
12
0
10
5
8
3
6
4
12
0
91
M18
9
0
11
3
0
6
5
4
11
0
59
NC11
2
3
0
2
3
3
2
1
3
0
74
LVC
2
3
2
2
3
3
3
1
3
2
92
DP
0
3
0
2
4
3
2
2
4
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
2
0
0
0
0
0
0
1
2
0
83
84
BC117 NC F 117
11
0
9
0
4
0
5
0
3
0
0
0
5
0
4
0
11
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.20 Iron (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. The North Carolina standard
for iron in freshwater is 1000 g/l. There is no standard for tidal salt water.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
680
1,090
1,560
811
1,670
1,670
1247
407
1670
680
87
M54
390
302
1,360
818
1,600
1,630
1017
544
1630
302
89
M35
380
199
1,020
593
1,470
971
772
429
1470
199
90
M23
450
113
784
603
821
616
565
236
821
113
91
M18
470
85
954
641
493
375
503
263
954
85
59
NC11
450
697
980
1,240
1,940
1,810
1186
545
1940
450
74
LVC
390
1,110
948
1,080
1,420
1,360
1051
338
1420
390
92
DP
525
839
1,010
858
2,030
2,160
1237
625
2160
525
79
SAR
1,930
1,960
479
421
1,120
908
1136
620
1960
421
80
LRC
1,580
1,300
671
424
1,270
1,460
1118
422
1580
424
83
84
65
BC117 NC F 117 6RC
320
510
4,020
1,160
438
1,960
975
773
748
748
516
518
1,060
763
1,010
1,170
847
691
906
641
1491
298
157
1224
1170
847
4020
320
438
518
64
GCO
4,700
1,910
295
200
499
868
1412
1576
4700
200
68
CO L
1,060
719
319
264
396
731
582
281
1060
264
Table 2.21 Lead (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for lead in freshwater and tidal salt water is 25 g/l.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
0
0
0
0
0
0
0
0
0
89
M35
0
0
0
0
0
0
0
0
0
0
90
M23
0
0
0
0
0
0
0
0
0
0
91
M18
0
0
0
0
0
0
0
0
0
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.22 Mercury (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for mercury in freshwater is 0.012 g/L and tidal
salt water is 0.025 g/L.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
0
0
0
0
0
0
0
0
0
89
M35
0
0
0
0
0
0
0
0
0
0
90
M23
0
0
0
0
0
0
0
0
0
0
91
M18
0
0
0
0
0
0
0
0
0
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.23 Nickel (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for nickel in freshwater is 88 g/L and tidal
salt water is 8.2 g/L.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
0
0
0
0
0
0
0
0
0
87
M54
0
15
0
0
0
0
3
6
15
0
89
M35
0
0
0
10
0
0
2
4
10
0
90
M23
0
0
0
0
0
0
0
0
0
0
91
M18
0
0
0
0
0
10
2
4
10
0
59
NC11
0
0
0
0
0
0
0
0
0
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
0
0
0
0
0
0
0
0
83
84
BC117 NC F 117
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
0
0
0
0
0
0
0
0
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.24 Zinc (g/l) at the Lower Cape Fear River Program stations for the 2002-2003 monitoring period. A zero value represents
a measurement below the analytical detection limit. The North Carolina standard for zinc in freshwater is 50 g/L and tidal
salt water is 86 g/L.
DWQ#
month
AUG
O CT
DEC
FEB
APR
JUN
me an
std de v
max
min
72
NAV
0
12
0
0
0
0
2
4
12
0
87
M54
0
18
0
0
0
0
3
7
18
0
89
M35
0
17
0
0
0
0
3
6
17
0
90
M23
0
21
0
13
17
0
9
9
21
0
91
M18
0
17
0
0
0
0
3
6
17
0
59
NC11
0
10
0
0
0
13
4
5
13
0
74
LVC
0
0
0
0
0
0
0
0
0
0
92
DP
0
0
0
0
0
0
0
0
0
0
79
SAR
0
0
0
0
0
0
0
0
0
0
80
LRC
0
0
11
0
0
0
2
4
11
0
83
84
BC117 NC F 117
15
0
12
0
15
0
25
0
10
0
10
0
15
0
5
0
25
0
10
0
65
6RC
0
0
0
0
0
0
0
0
0
0
64
GCO
0
19
0
0
0
0
3
7
19
0
68
CO L
0
0
0
0
0
0
0
0
0
0
Table 2.25 Chlorophyll a (g/L) at the Lower Cape Fear River stations, 2002-2003.
DWQ# 72
month NAV
7.2
JUL
6.0
AUG
2.3
SEP
O CT 2.2
0.8
NO V
1.2
DEC
1.9
JAN
3.1
FEB
2.1
MAR
1.9
APR
1.8
MAY
2.2
JUN
me an 2.7
std de v 1.8
7.2
max
0.8
min
73
HB
9.0
6.6
2.5
3.5
0.6
1.2
1.7
2.9
1.8
2.1
1.7
2.2
3.0
2.3
9.0
0.6
75
BRR
15.3
20.1
5.8
4.8
1.2
1.0
2.5
4.9
2.4
1.8
2.3
2.3
5.4
5.8
20.1
1.0
87
M54
20.1
13.5
3.6
3.8
2.5
1.2
2.1
3.2
2.6
2.1
1.8
2.1
4.9
5.5
20.1
1.2
88
M42
20.7
33.4
4.8
4.9
2.6
1.2
1.7
5.1
4.0
1.7
2.6
2.2
7.1
9.4
33.4
1.2
89
M35
17.2
27.9
13.5
3.7
2.7
1.9
1.8
5.9
3.6
1.4
2.0
2.1
7.0
8.0
27.9
1.4
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std de v
max
min
79
SAR
0.8
0.3
1.3
0.3
0.2
0.1
1.5
7.6
1.7
0.7
1.0
1.0
1.4
1.9
7.6
0.1
78
94
77
GS NC403 PB
53.3
5.8
40.8
1.3
6.6
31.7
1.6
1.8
6.2
31.5
2.4 177.8
1.9
1.2
3.3
0.4
0.9
0.9
3.7
1.8
1.5
23.5
2.3
2.2
2.5
3.0
1.3
1.1
0.6
1.1
3.0
2.5
1.2
1.5
1.4
1.1
10.4
2.5
22.4
16.1
1.8
48.6
53.3
6.6 177.8
0.4
0.6
0.9
80
LRC
2.9
1.8
29.5
0.8
0.4
0.9
1.9
25.0
3.0
0.8
0.7
1.7
5.8
9.7
29.5
0.4
81
83
82
RO C BC117 BCRR
2.4
3.4
58.4
2.3
1.0
9.4
8.0
1.3
1.9
7.3
0.8
16.2
1.9
0.4
0.6
0.4
0.4
0.2
1.6
0.7
0.5
8.2
1.1
0.5
1.5
4.5
2.0
0.6
0.7
0.9
0.5
1.2
0.6
1.1
1.2
1.0
3.0
1.4
7.7
2.9
1.2
16.0
8.2
4.5
58.4
0.4
0.4
0.2
69
ANC
13.2
21.8
18.7
9.9
5.2
2.0
6.0
4.4
4.9
0.7
1.8
1.9
7.5
6.7
21.8
0.7
86
M61
9.4
7.0
4.3
3.6
2.1
1.2
2.5
3.2
2.2
1.6
1.5
1.8
3.4
2.4
9.4
1.2
90
M23
2.8
4.4
3.2
2.0
2.4
2.8
1.7
5.6
6.7
2.3
2.7
4.4
3.4
1.5
6.7
1.7
91
M18
2.0
1.7
4.0
2.4
2.3
2.9
3.9
4.8
6.9
3.9
2.9
10.4
4.0
2.4
10.4
1.7
93
SPD
2.0
4.8
3.1
2.6
2.4
2.5
2.2
7.6
6.6
2.8
3.5
3.1
3.6
1.7
7.6
2.0
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
me an
std dev
max
min
59
74
NC11 LVC
12.6 19.3
12.7
7.0
1.5
0.6
4.3
1.7
0.7
0.7
1.3
0.9
1.6
2.0
5.1
5.4
2.7
2.6
3.7
4.8
2.2
1.5
3.6
3.7
4.3
4.2
3.9
5.0
12.7 19.3
0.7
0.6
DWQ# 65
month 6RC
0.4
JUL
0.5
AUG
1.4
SEP
O CT 0.4
0.5
NO V
0.4
DEC
0.7
JAN
10.5
FEB
1.0
MAR
0.6
APR
0.2
MAY
0.8
JUN
me an 1.5
std dev 2.7
max 10.5
0.2
min
64
LCO
0.5
0.6
0.5
0.3
0.5
0.2
0.5
1.0
1.2
0.6
0.4
5.2
1.0
1.3
5.2
0.2
61
AC
25.7
9.6
1.6
2.1
0.7
1.0
1.9
5.4
2.7
3.6
2.0
3.9
5.0
6.7
25.7
0.7
92
DP
3.4
3.0
2.3
2.9
0.7
0.9
1.9
4.4
2.5
3.7
1.9
3.3
2.6
1.1
4.4
0.7
BBT
2.7
2.7
1.6
0.5
0.5
0.7
0.8
3.6
1.5
1.5
1.2
1.4
1.6
0.9
3.6
0.5
71
IC
12.1
5.0
2.7
0.8
0.3
0.8
1.4
4.5
2.0
2.4
1.7
2.0
3.0
3.1
12.1
0.3
85
70
84
NCF6 B210 NCF117
14.2
3.8
3.9
10.4
1.2
5.2
5.9
0.6
3.0
3.1
0.6
0.8
1.2
0.2
0.3
1.0
0.1
0.2
0.6
0.4
0.3
1.3
0.5
1.2
0.8
1.2
0.6
0.7
0.5
0.8
1.1
0.3
0.5
0.4
0.5
0.3
3.4
0.8
1.4
4.3
1.0
1.6
14.2
3.8
5.2
0.4
0.1
0.2
63
GCO
1.4
2.2
1.7
4.9
1.4
0.5
0.3
2.6
1.3
0.7
0.8
0.9
1.6
1.2
4.9
0.3
62
SR
119.2
31.7
35.1
5.2
0.9
0.3
1.5
12.1
2.0
0.6
0.6
1.0
17.5
32.8
119.2
0.3
66
BRN
2.8
1.3
0.4
0.6
0.7
0.4
2.4
11.7
4.5
0.8
0.8
1.2
2.3
3.1
11.7
0.4
67
68
HAM CO L
17.7 14.1
8.7
14.8
3.3
2.2
12.2
1.2
0.7
1.3
0.2
0.1
0.8
0.2
9.2
1.1
3.5
1.7
0.5
0.6
0.4
1.7
0.6
0.7
4.8
3.3
5.5
5.0
17.7 14.8
0.2
0.1
All station
mean
15.8
8.8
4.9
9.4
1.2
0.9
1.5
5.9
2.7
1.6
1.5
2.1
Table 2.26 Biochemical Oxygen Demand (mg/L) at the Lower Cape Fear River stations, 2002-2003.
5-Day Biochemical Oxygen Demand
DWQ#
month
JUL
AUG
SEP
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
mean
max
min
stdev
59
NC11
1.9
1.7
1.4
1.3
0.7
1.1
1.2
1.0
0.8
1.4
1.2
1.2
1.2
1.2
1.9
0.7
0.3
61
AC
1.2
2.8
1.6
2.3
1.0
2.3
1.4
1.4
1.0
2.2
1.2
1.5
1.5
1.7
2.8
1.0
0.6
74
LVC
1.9
1.7
1.2
1.2
1.2
1.1
1.1
1.7
1.3
2.5
4.2
1.8
1.5
1.7
4.2
1.1
0.9
BBT
1.1
0.8
1.1
1.1
0.8
1.3
1.3
1.1
0.7
1.3
1.1
1.1
1.1
1.3
0.7
0.2
70
84
B210 NCF117
1.2
0.7
0.4
0.7
1.3
0.8
1.3
1.1
0.7
0.5
1.1
1.3
0.8
0.9
0.8
0.9
0.5
0.8
0.9
1.2
1.1
1.2
1.0
1.0
1.0
0.9
0.9
0.9
1.3
1.3
0.4
0.5
0.3
0.2
65
6RC
1.5
0.8
1.9
70
84
B210 NCF117
2.5
2.2
2.0
2.4
4.3
3.0
2.8
2.7
2.2
2.0
2.5
4.0
1.9
2.7
1.9
2.6
2.3
3.5
2.8
3.9
3.3
3.8
3.2
3.4
2.5
2.9
2.6
3.0
4.3
4.0
1.9
2.0
0.7
0.7
84
6RC
3.7
2.7
6.2
1.3
0.8
1.3
1.0
0.6
1.8
1.1
1.4
1.3
1.2
1.9
0.6
0.4
64
LCO
1.2
1.2
1.6
0.8
1.2
0.9
2.3
0.9
1.6
2.1
2.0
1.3
1.3
1.4
2.3
0.8
0.5
63
GCO
1.6
1.0
3.6
2.5
1.2
0.8
0.7
0.8
0.3
1.1
1.1
1.0
1.1
1.3
3.6
0.3
0.9
66
BRN
2.0
1.1
1.1
1.0
1.1
1.0
0.9
1.4
1.6
0.8
1.4
1.2
1.1
1.2
2.0
0.8
0.3
67
HAM
2.9
2.1
1.7
1.5
2.2
1.2
0.9
1.6
3.4
1.2
1.5
1.6
1.6
1.8
3.4
0.9
0.7
68
COL
2.3
3.4
1.4
1.3
1.5
0.9
0.5
0.6
0.3
0.7
1.2
0.9
1.1
1.3
3.4
0.3
0.9
All stations
mean
1.6
1.5
1.6
1.4
1.1
1.2
1.1
1.1
1.1
1.4
1.5
1.3
65
LCO
3.1
3.1
4.3
2.4
2.9
2.1
3.3
2.6
6.7
6.8
6.5
3.2
3.2
3.9
6.8
2.1
1.7
64
GCO
4.6
3.9
9.1
7.2
3.0
2.0
2.0
2.6
2.3
3.2
3.4
2.7
3.1
3.8
9.1
2.0
2.2
63
BRN
4.8
2.3
2.5
2.5
2.4
2.2
2.0
2.4
6.2
2.8
3.5
3.5
2.5
3.1
6.2
2.0
1.3
66
HAM
7.1
4.9
4.6
4.1
5.3
2.7
2.4
2.6
9.1
3.6
3.9
4.6
4.4
4.6
9.1
2.4
1.9
67
COL
4.8
7.5
4.2
3.0
3.4
1.2
1.5
1.9
1.9
2.3
3.3
2.9
3.0
3.2
7.5
1.2
1.7
68 All stations
mean
4.0
4.0
4.6
3.5
3.0
2.9
2.5
2.7
4.3
4.3
4.2
3.6
20-Day Biochemical Oxygen Demand
DWQ#
month
JUL
AUG
SEP
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
median
mean
max
min
stdev
59
NC11
4.5
4.4
4.6
2.6
2.3
2.6
2.7
2.5
3.8
3.8
3.2
3.4
3.3
3.4
4.6
2.3
0.8
61
AC
3.0
6.9
5.3
5.8
3.1
6.7
3.4
3.6
4.2
5.8
3.2
3.6
3.9
4.6
6.9
3.0
1.5
74
LVC
4.9
4.7
4.1
2.4
4.1
2.8
2.7
4.4
5.4
7.2
9.0
5.1
4.6
4.7
9.0
2.4
1.9
BBT
3.0
2.7
3.4
2.7
2.5
3.6
3.1
2.9
3.2
3.6
3.3
3.1
3.1
3.6
2.5
0.4
2.8
2.4
2.8
2.1
3.0
4.9
3.4
3.8
3.0
3.4
6.2
2.1
1.2
Table 2.27 Fecal Coliform Bacteria (cfu/100 mL) at the Lower Cape Fear River stations, 2002-2003.
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
Ge ome an
72
NAV
125
43
45
20
45
23
29
4
82
30
14
44
42
31
125
4
31
73
HB
45
70
51
16
33
21
30
5
76
32
12
39
36
21
76
5
29
75
BRR
58
75
86
55
70
11
20
4
110
20
24
27
47
32
110
4
33
86
M61
10
33
50
33
34
11
25
9
48
22
13
38
27
14
50
9
23
87
M54
7
29
62
27
24
5
22
5
45
22
15
24
24
16
62
5
18
88
M42
3
14
11
7
19
5
15
2
42
18
7
21
14
11
42
2
10
89
M35
0
2
7
4
5
3
5
3
21
22
5
16
8
7
22
0
4
90
M23
4
0
1
1
2
2
2
0
2
7
4
30
5
8
30
0
1
91
M18
1
3
1
0
2
0
1
0
5
5
4
13
3
4
13
0
1
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
Ge ome an
69
ANC
145
195
70
233
267
220
64
30
54
41
106
175
133
80
267
30
107
79
SAR
37
25
409
54
46
200
98
35
42
110
46
130
103
105
409
25
71
78
GS
35
117
364
300
68
140
41
20
60
51
273
120
132
111
364
20
92
94
NC403
86
81
70
29
20
114
10
6
4
12
32
24
41
36
114
4
25
77
PB
74
21
655
50
52
207
18
10
14
115
114
25
113
173
655
10
53
80
81
83
82
LRC RO C BC117 BCRR
43
60
297
49
1,600
40
155
166
490
664
236
600
20
71
167
290
121
64
136
103
673
460 1,430 920
77
77
410
50
110
88
369
33
42
78
69
78
41
43
60
3
32
40
175
97
88
94
79
40
278
148
299
202
445
190
358
268
1,600 664 1,430 920
20
40
60
3
107
90
195
87
93
SPD
0
3
5
8
12
11
2
0
2
6
7
18
6
5
18
0
2
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
Ge ome an
59
74
NC11 LVC
12
11
10
8
58
61
6
24
36
31
13
19
84
25
7
5
134
170
70
32
5
7
43
37
40
36
39
43
134
170
5
5
23
22
DWQ#
month
JUL
AUG
SEP
O CT
NO V
DEC
JAN
FEB
MAR
APR
MAY
JUN
mean
std de v
max
min
Ge ome an
65
6RC
337
36
54
31
70
50
70
35
66
48
11
46
71
82
337
11
51
64
LCO
26
8
44
195
113
23
39
22
64
22
56
44
55
50
195
8
39
61
AC
12
18
39
19
18
14
72
8
100
76
4
39
35
30
100
4
23
92
DP
42
31
45
11
29
15
56
5
104
55
21
29
37
26
104
5
28
71
IC
45
44
52
21
34
20
39
5
79
41
23
38
37
18
79
5
31
63
GCO
50
39
64
64
76
33
42
17
80
59
14
49
49
20
80
14
44
62
SR
52
20
500
560
89
72
114
94
235
51
59
51
158
175
560
20
97
66
BRN
843
27
134
44
203
52
93
33
2,310
64
84
180
339
632
2,310
27
121
85
70
84
NCF6 B210 NCF117
41
47
46
51
33
27
39
47
22
21
32
18
77
70
62
47
34
16
27
41
27
11
24
11
22
36
33
17
23
15
52
28
39
52
40
34
38
38
29
18
12
14
77
70
62
11
23
11
33
36
26
67
68
HAM CO L
520
449
7
157
215
64
106
35
600
80
81
13
42
12
19
11
4,360
9
50
7
52
12
140
120
516
81
1,174 121
4,360 449
7
7
115
33
All station
mean
104
92
163
72
75
147
53
31
267
38
43
55
Figure 2.1 Mean salinity at the Lower Cape Fear River Program estuarine stations.
30
25
Salinity (ppt)
20
15
10
5
0
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
June 1995-June 2003
M23
M18
NCF6
Figure 2.2 Mean dissolved oxygen concentrations at the Lower Cape Fear River Program
channel stations.
10
9
8
Dissolved Oxygen (mg/L)
7
6
NC State
Standard
5
4
3
2
1
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
BBT
Figure 2.3 Mean field turbidity at the Lower Cape Fear River Program channel
stations.
NC state tidal freshwater
50
45
40
Field Turbidity (NTU)
35
30
NC state tidal saltwater standard
25
20
15
10
5
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
M18
June 1995-June 2003
NCF117
NCF6
B210
BBT
Figure 2.4 Mean light attenuation at the Lower Cape Fear River Program stations.
4.50
4.00
3.50
Light Attenuation (k)
3.00
2.50
2.00
1.50
1.00
0.50
0.00
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
SPD
NCF6
BBT
Figure 2.5 Mean total nitrogen at the Lower Cape Fear River Program channel
stations.
1,800
1,600
1,400
Total Nitrogen (g/L)
1,200
1,000
800
600
400
200
0
NC11
AC
DP
IC
NAV
HB
BRR
July 2002-June 2003
M61
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
Figure 2.6 Mean nitrate+nitrite at the Lower Cape Fear River Program channel
stations.
800
700
Nitrate+Nitrite (g/L)
600
500
400
300
200
100
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
BBT
Figure 2.7 Mean ammonium concentrations at the Lower Cape Fear River Program
channel stations.
250
Ammonium (g/L)
200
150
100
50
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
BBT
Figure 2.8 Mean total Kjeldahl nitrogen at the Lower Cape Fear River Program
channel stations.
1,200
Total Kjeldahl Nitrogen (g/L)
1,000
800
600
400
200
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
Figure 2.9 Mean total phosphorus at the Lower Cape Fear River Program channel
stations.
200
180
160
Total Phosphorus (g/L)
140
120
100
80
60
40
20
0
NC11
AC
DP
IC
NAV
HB
BRR
July 2002-June 2003
M61
M54
M42
M35
June 1995-June 2003
M23
M18
NCF117
NCF6
B210
Figure 2.10 Mean orthophospate concentrations at the Lower Cape Fear River
Program channel stations.
120
Orthophosphate (g/L)
100
80
60
40
20
0
NC11
AC
DP
IC
NAV
HB
BRR
July 2002-June 2003
M61
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
BBT
Figure 2.11 Mean chlorophyll a concentrations at the Lower Cape Fear River
Program channel stations.
8
7
Chlorophyll a (g/L)
6
5
4
3
2
1
0
NC11
AC
DP
IC
NAV
HB
BRR
M61
July 2002-June 2003
M54
M42
M35
M23
June 1995-June 2003
M18
NCF117
NCF6
B210
BBT
Figure 2.12 Geometric mean fecal coliform bacteria concentrations at the Lower
Cape Fear River Program channel stations.
50
45
Fecal Coliform Bacteria (cfu/100 mL)
40
35
30
25
20
15
10
5
0
NC11
AC
DP
IC
NAV
HB
BRR
July 2002-June 2003
M61
M54
M42
M35
M23
February 1996-June 2003
M18
NCF117
NCF6
B210
3.0 Use Support by Subbasin in the
Lower Cape Fear River System
by
Heather A. Wells, Michael A. Mallin, and James F. Merritt
Center for Marine Science
University of North Carolina at Wilmington
Wilmington, NC 28409
3.0 Use Support Comparison by Subbasins
A compilation and comparison using information from the North Carolina
Department of Environmental and Natural Resources (NCDENR), Division of
Water Quality (DWQ) Cape Fear River Basinwide Water Quality Plan, July 2000,
and the research conducted by UNC-Wilmington, Center for Marine Science
(CMS), Lower Cape Fear River Program (LCFRP) for July 2002 - June 2003.
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. The
basinwide approach is a nonregulatory 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 the 2000 report is the
first of the five-year interval updates. 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;
- develop appropriate management strategies to protect and restore water
quality;
- assure equitable distribution of waste assimilative capacity for
dischargers; and
- improve public awareness and involvement in the management of the
state’s surface waters.
(NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
The NCDENR has divided the Cape Fear River Basin into three areas: an
upper basin, middle basin, and lower basin. The watershed is divided into 6
major hydrological areas by the US Geological Survey (USGS). 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 6-digit numbers
(03-06-01 to 03-06-24). (NCDENR, DWQ Cape Fear River Basinwide Water
Quality Plan, July 2000)
The Division of Water Quality (DWQ) conducts an assessment and
determines water classification according to their best-intended uses. Use
support ratings are established such as fully supporting (FS) if standard is
exceeded in < 10% of measurements, partially supporting (PS) if standard is
exceeded in 11-25% of measurements, or non supporting (NS) if standard is
exceeded in > 25% of measurements. DWQ also utilizes other criteria, such as
the benthic community composition and fisheries populations. (NCDENR, DWQ
Cape Fear River Basinwide Water Quality Plan, July 2000)
UNCW researchers have adopted a rating system that incorporates some
of the guidelines used by DWQ. Water quality ratings are as follows for the
parameters that have North Carolina State Standards (dissolved oxygen,
chlorophyll a, fecal coliform bacteria, and turbidity): good quality (G) if standard
is exceeded in < 10% of measurements, fair quality (F) if standard is exceeded in
11-25% of measurements, or poor quality (P) if standard is exceeded in > 25% of
measurements. UNCW also rates stations where nutrient concentrations exceed
levels noted to be problematic in the scientific literature.
Some of the subbasins have waters that are on the state’s year 2000
303(d) list. Section 303(d) of the Clean Water Act (CWA) requires states to
develop a list of waters not meeting water quality standards or which have
impaired uses. Waters may be excluded from the list if existing control strategies
for point and nonpoint source pollution will achieve the standards or uses. Listed
waters must be prioritized, and a management stategy or total maximum daily
load (TMDL) must be developed for all listed waters. (NCDENR, DWQ Cape
Fear River Basinwide Water Quality Plan, July 2000)
The ambient data was taken by DWQ from September 1993 to August
1998 for the July 2000 Basinwide Report. The next data window will be from
September 1998 to August 2003 and the basinwide plan will be published in
2005. (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July
2000)
For more information consult the NC Division of Water Quality Basinwide
Planning Website: http://h2o.enr.state.nc.us/basinwide
The 35 stations monitored by UNC-Wilmington’s Center for Marine Science
(CMS), for the Lower Cape Fear River Program (LCFRP) fall into the middle and
lower basins designated by the NCDENR. The stations are in the following
subbasins:
Subbasin #
03-06-16 (middle)
UNC-W, LCFRP Stations
BRN, HAM, NC11
03-06-17 (lower)
LVC, AC, DP, IC, NAV, HB, BRR, M61,
M54, M42, M35, M23, M18, SPD
03-06-18 (middle)
SR
03-06-19 (middle)
LCO, GCO, 6RC
03-06-20 (middle)
COL, B210, BBT
03-06-21 (lower)
N403
03-06-22 (lower)
PB, GS, SAR, LRC, ROC
03-06-23 (lower)
ANC, BCRR, BC117, NCF117, NCF6
3.2 Methods
Each subbasin will be addressed separately; with a description and map
with the Lower Cape Fear River Program (LCFRP) stations designated, and
municipalities noted. This will be followed by a summary of the information
published by NCDENR and DWQ in the Cape Fear River Basinwide Water
Quality Plan, July 2000. UNCW results and comments for the 2002-2003
monitoring period will follow, with graphical representation when chronic
problems have been observed.
3.3 Cape Fear River Subbasin 03-06-16
Includes the Cape Fear River, Harrison Creek and Turnbull
Creek
Municipalities: City of Elizabethtown
LCFRP Station Codes (DWQ #): BRN (66), HAM (67), NC11 (59)
DWQ/UNCW ambient monitoring site(s): NC11
Waterbody: Lower Cape Fear River
Location: Within Bladen County, Browns and Hammonds Creeks are near
Elizabethtown. NC11 is on the main stem of the Cape Fear River
Lat/Lon: N 34 36.816 W 78 35.077 (BRN) to
N 34 23.798 W 78 16.071 (NC11)
BRN
HAM
NC11
Use Support Ratings, from NCDENR, DWQ (2000 Basinwide Report):
Fully Supporting:
240.8 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
8.5 mi.
Not Rated:
11.8 mi.
The portion of the Cape Fear River within this subbasin is deep and slow moving.
There are several natural lakes and streams that are tannin-stained with low pH
blackwaters. Land use is mostly forest and marsh with some agriculture within
the subbasin. There are eight permitted dischargers, mostly near Elizabethtown.
Four of the largest dischargers, Veeder-Root, Smithfield Foods Incorporated in
Tar Heel, Alamac Knit Fabrics in Elizabethtown, and Dupont of Fayetteville,
discharge into the Cape Fear River. (NCDENR, DWQ Cape Fear River
Basinwide Water Quality Plan, July 2000)
Portions of Turnbull Creek and Harrisons Creek were considered partially
supporting (PS) in the 1996 Basinwide Plan. Both are currently fully supporting
(FS) and no longer on the state’s 303(d) list. Brown’s Creek (8.5 miles from
source to Cape Fear River) is non supporting (NS) according to recent DWQ
monitoring because of an impaired biological community. Urban nonpoint
sources and sanitary sewer overflows from the City of Elizabethtown are possible
sources of impairment. This stream is on the state’s year 2000 303(d) list.
(NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
Approximately 1% of the waters in this subbasin are impaired by nonpoint source
pollution (mostly urban). All of the waters in this subbasin are affected by
nonpoint sources. DENR, other state agencies and environmental groups have
programs and initiatives underway to address water quality problems associated
with nonpoint sources. (NCDENR, DWQ Cape Fear River Basinwide Water
Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: BRN, HAM, NC11
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. There are also several
concentrated animal operations within the area.
BRN - representative of
shallow creeks that enter
the Cape Fear River
Cape Fear
NC11 - main stem of
River, deep channel,
relatively slow moving,
freshwater yet tidally
influenced
The sites at Browns Creek (BRN) and North Carolina Highway 11 (NC11) were
found to have a good quality rating for dissolved oxygen, meeting the North
Carolina State Standard of 5.0 mg/L in all sampled months. Hammonds Creek
(HAM), a small channelized tributary, was rated as poor, with dissolved oxygen
levels falling below 5.0 mg/L in four of the twelve sampled months (33% of the
time). The lowest concentrations of dissolved oxygen at HAM were 1.4 mg/L,
found in July 2002. The dissolved oxygen concentrations for Hammonds Creek
are represented graphically in Figure 3.3.1.
All sites within this subbasin were found to have a good quality rating for
chlorophyll a concentrations. The North Carolina State Standard for chlorophyll a
of 40 g/L was not exceeded at HAM, BRN, or NC11 during the 2002-2003
monitoring period.
Fecal coliform bacteria concentrations were low at NC11, receiving a good
quality rating with no samples over the NC State Standard for human contact
waters of 200 CFU/100mL in 2002-2003. Browns Creek (BRN) received a fair
quality rating for fecal coliform bacteria concentrations, exceeding the standard
25% of the time. Hammonds Creek (HAM) was rated as poor quality for fecal
coliform bacteria concentrations, due to exceeding the NC State Standard in 33%
of samples. Fecal coliform bacteria concentrations were greater than 4,000
CFU/100mL in March 2003 at HAM. Also there were elevated turbidity
concentrations noted during March sampling, reaching 125 NTU at HAM. There
was heavy rain previous to and during the March Cape Fear River sampling, and
high water with flooded banks was noted at all sites within this subbasin. Fecal
coliform bacteria concentrations for Browns Creek and Hammonds Creek are
represented graphically in Figure 3.3.2.
Though there were elevated turbidity levels noted in the March 2003 sampling, all
sites within this subbasin were rated as good quality for turbidity concentrations.
The March 2003 samples were the only ones to exceed the 50 NTU North
Carolina State Standard for turbidity. The concentrations for March 2003 were
85 NTU, 125 NTU, and 86 NTU for BRN, HAM, and NC11 respectively. The
means for the 2002-2003 sampling period were 12 NTU (BRN), 17 NTU (HAM)
and 27 NTU (NC11).
12.0
10.0
8.0
HAM
6.0
4.0
2.0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0.0
JUL
Dissolved Oxygen (mg/L)
Dissolved Oxygen Concentrations (mg/L)
for 2002-2003 monitoring period
Figure 3.3.1 Dissolved oxygen concentrations (mg/L) for Hammonds Creek
(HAM). The line shows the NC State Standard of 5.0 mg/L.
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
BRN
HAM
JUL
Fecal Coliform Bacteria
(CFU/100mL)
Fecal Coliform Bacteria Concentrations (CFU/100mL)
for 2002-2003 monitoring period
Figure 3.3.2. Fecal coliform bacteria concentrations (CFU/100mL) for Browns
Creek (BRN) and Hammonds Creek (HAM). The line shows the NC State
Standard for human contact waters of 200 CFU/100mL.
3.4 Cape Fear River Subbasin 03-06-17
Includes Town Creek, Smith Creek and the Brunswick River
Municipalities: City of Wilmington and Town of Southport
LCFRP Station Codes (DWQ #): LVC (74), AC (61), DP (92), IC (71), NAV (72),
HB (73), BRR (75), M61 (86), M54 (87), M42 (88), M35 (89), M23 (90), M18 (91),
SPD (93)
DWQ/UNCW ambient monitoring site(s): NAV, M61, M54
Waterbody: Lower Cape Fear River and Estuary
Location: Lower Cape Fear River including Livingston Creek, downstream to
estuarine area off Town of Southport
Lat/Lon: N 34 21.108 W 78 12.077 (LVC)
N 33 55.025 W 78 02.230 (SPD)
LVC
AC
DP
IC
NAV
HB
BRR
M61
M54
M42
M35
M23
M18
SPD
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
251.5 mi.
Partially Supporting:
3.8 mi.
Not Supporting:
0.0 mi.
Not Rated:
65.5 mi.
Estuarine Waters
Fully Supporting:
Partially Supporting:
Not Supporting:
Not Rated:
16,314 ac.
7,211 ac.
0.0 ac.
925 ac.
This subbasin is located in the outer coastal plain and in estuarine regions of the
basin. Significant dischargers in this subbasin are the City of Wilmington and the
Town of Southport. There are 49 permitted dischargers in the subbasin; half of
which discharge directly into the Cape Fear River. The largest dischargers are
International Paper, Wilmington North Side WWTP and Wilmington South Side
WWTP. (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July
2000)
Portions of Livingston Creek, the Cape Fear River and estuarine areas were
identified as impaired in the 1996 Basinwide Water Quality Plan (NCDENR,
DWQ). Currently Livingston Creek is listed as fully supporting (FS) and is longer
on the 303(d) list of impaired waters. The Cape Fear River is currently partially
supporting (PS), because of an impaired biological community. The International
Paper Board discharge and nonpoint source pollution are possible causes of
impairment, and this segment of the river is on the state’s year 2000 303(d) list.
The Cape Fear River Estuary (5000 acres) is partially supporting (PS) and is on
the state’s year 2000 303(d) list. The cumulative impacts from WWTP
discharges in the subbasin as well as nonpoint source pollution are suspected to
be the significant contributors to the impairment. Swamp water drainage may
also be a source of low dissolved oxygen (DO) waters feeding into the estuary.
Possible sources of nonpoint source pollution include marinas, canal systems,
and septic systems. (NCDENR, DWQ Cape Fear River Basinwide Water Quality
Plan, July 2000)
Approximately 45% of the waters in this subbasin are impaired by nonpoint
source pollution. All the waters of the subbasin are affected by nonpoint sources.
The 303(d) list approach will be to develop a TMDL (Total Maximum Daily Load)
for this segment of the Cape Fear River because of low DO levels. Because of
the nature of the river/estuary system in this portion of the basin, addressing
water quality issues must not be limited to problems in impaired segments alone.
Because this segment of the river and estuary are impaired, issuance of new and
expanding discharges that would further increase the load of oxygen-consuming
waste into these waters will be considered on a case by case basis. (NCDENR,
DWQ, Cape Fear River Basinwide Water Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: LVC, AC, DP, IC, NAV, HB, BRR, M61, M54, M42,
M35, M23, M18, SPD
Data collection: some stations since 1995, all sampled since 1998
Sampling relevance: below point source dischargers, including City
of Wilmington, and nonpoint source pollution
AC - representative of riverine
system
channel
stations, low salinity, fairly narrow
HB - riverine station, upstream of
cape
more open,
Wilmington, shows change of
from upland forested areas to
wider river channel
M35 - representative of the
estuarine stations, wider channel,
strong tidal influence
Sites rated as good quality for dissolved oxygen concentrations include: AC,
M42, M35, M23, and M18. The following sites were rated as fair quality for
dissolved oxygen, with the percentage of samples not meeting the standard of
5.0 mg/L shown in parentheses: LVC (17%), DP (25%), IC (17%), HB (25%),
BRR (17%), M61 (25%), and M54 (17%). Navassa (NAV) was rated as poor
quality for dissolved oxygen concentrations due to levels below 5.0mg/L in 33%
of all samples. Dissolved oxygen concentrations are represented graphically for
DP, NAV, HB and M61 in Figure 3.4.1. In summer months, the riverine sampling
sites in this subbasin are monitored weekly, and the estuary stations are
monitored biweekly. Low dissolved oxygen levels are a concern during summer
months because there is generally less rain, more transpiration, lower flow levels,
and the warmer waters hold less dissolved oxygen than colder waters. The
summer values are represented graphically in Figure 3.4.2.
All sites within this subbasin were found to be good quality in terms of chlorophyll
a concentrations. None of the sampled locations exceeded the 40 g/L North
Carolina State Standard on any sample occasion.
All sites within this subbassin were rated as good quality for fecal coliform
bacteria concentrations. No site exceeded the 200 CFU/100mL NC State
Standard for human contact waters. The NC State Standard for Shellfishing
states that geometric mean cannot exceed 14 CFU/100mL and no more than
10% of samples may exceed 43 CFU/100mL. When considering this subbasin
from a shellfishing perspective, the stations in the middle estuary (from river
channel marker 35 (M35) and upstream) are poor quality due to concentrations
with a geometric mean above 14 CFU/100mL (NC State Standard for
Shellfishing). The lower estuary stations (M23 and downstream) were more
suited for shellfishing. M23, M18 and SPD all maintained fecal coliform bacteria
geomeans below 14 CFU/100mL and did not exceed 43 CFU/100mL in more
than 10% of samples. The higher salinities found in the lower estuary
significantly increase mortality of fecal coliform bacteria.
For turbidity, the upper stations within this watershed were evaluated using the
North Carolina State Standard for freshwater of 50 NTU. All stations
downstream of NAV were evaluated with the NC State Standard for brackish
waters of 25 NTU. The following stations were good quality for turbidity: LVC,
AC, DP, IC, NAV, M23, M18, and SPD. The following sites were rated as fair
quality for turbidity: M61, M42, and M35. The sites that were rated as poor were
found in the lower estuary, and rated by the brackish water standard of 25 NTU.
HB and BRR were both poor quality for turbidity, exceeding the standard 33% of
the time. M54 was also rated poor quality, exceeding the standard in 50% of
sampled months.
Dissolved Oxygen Concentrations (mg/L)
for 2002-2003 monitoring period
DP
NAV
HB
M61
12
10
8
6
4
2
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0
JUL
Dissolved Oxygen (mg/L)
14
Figure 3.4.1 Dissolved oxygen concentrations (mg/L) for DP, NAV, HB, and
M61 for the 2003-2003 monitoring period. The solid line shows the NC State
Standard of 5.0 mg/L and the dashed line shows the swampwater standard of 4.0
mg/L.
DP
NAV
HB
M61
9/25/02
9/17/02
9/11/02
9/04/02-9/5/02
8/29/02
8/22/02
8/16/02
8/6/02-8/7/02
7/25/02
7/17/02
7/9/02-7/10/02
7/3/02
6/27/02
6/19/02
6/13/02
8
7
6
5
4
3
2
1
0
6/4/02-6/5/02
Dissolved Oxygen (mg/L)
Dissolved Oxygen Concentrations (mg/L)
in Summer Months for 2002
Figure 3.4.2 Dissolved oxygen concentrations (mg/L) in summer months,
weekly sampling DP, NAV, and HB, and biweekly sampling of M61. The line
shows the NC State Standard of 5.0 mg/L.
3.5 Cape Fear River Subbasin 03-06-18
Includes the South River and Big Creek
Municipalities: Cities of Dunn and Roseboro
LCFRP Station Codes (DWQ #): SR (62)
DWQ/UNCW ambient monitoring site(s): none
Waterbody: South River
Location: Harnett, Cumberland, Bladen and Sampson Counties. South River
upstream of confluence with the Black River
Lat/Lon: N 35 09.360 W 78 38.408 (SR)
SR
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
165.9 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
0.0 mi.
Not Rated:
113.7 mi.
This subbasin is located on the inner coastal plain and includes South River and
Black River (Little Black River), both major tributaries of the Cape Fear River.
Land use is primarily agriculture in the form of animal operations (mostly hog
farms). Most streams are slow moving black-water swamp streams. There are
three permitted dischargers within this subbasin. (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan, July 2000)
The South River (7.2 miles from source to NC 13) and the Little Black River (from
Dunn to I-95) were both rated as partially supporting (PS) in the 1996 plan.
Neither river was sampled by DWQ because of low flow conditions, each is
currently not rated (NR). Both remain on the state’s year 2000 303(d) list.
Portions of the South River are not impaired; however, because of fish
consumption advisories, this 70.9-mile segment is on the 303(d) list. (NCDENR,
DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
All the waters of the subbasin are affected by nonpoint sources. The Nature
Conservancy has acquired a 295-acre tract in the Black River Watershed
Outstanding Resource Waters (ORW) to demonstrate how the riparian buffer
protects the river from nonpoint source pollution. (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: SR
Data collection: since February 1996
Sampling relevance: Below City of Dunn, hog operations in
watershed
SR - below the Mingo
Swamp
South River (SR) was found to be poor quality for dissolved oxygen
concentrations. The North Carolina State Standard of 5.0 mg/L was not met 42%
of the time, and the swampwater standard of 4.0 mg/L was not 33% of the time.
The lowest levels were found in late summer and early fall, with October of 2002
having the lowest value of 0.4 mg/L. The mean for this site for 2002-2003 was
5.8 mg/L. The values for the 2002-2003 dissolved oxygen concentrations are
represented graphically in Figure 3.5.1.
This site was found to be good quality for chlorophyll a, with only one sample
exceeding the 40 g/L North Carolina State Standard.
SR was rated as fair quality for fecal coliform bacteria concentrations, exceeding
the NC State Standard of 200 CFU/100mL in 25% of all samples. The highest
concentrations were in September and October 2002, measuring 500
CFU/100mL and 560 CFU/100mL respectively.
This site was found to be good quality in terms of turbidity, with no samples
above the 50 NTU North Carolina State Standard. This site had a mean turbidity
value of 9 NTU for the 2002-2003 monitoring period.
Dissolved Oxygen Concentration (mg/L)
for 2002-2003 monitoring period
Dissolved Oxygen (mg/L)
12
10
SR
8
6
4
2
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
JUL
0
Figure 3.5.1 Dissolved oxygen concentrations (mg/L) for South River (SR) for
the 2002-2003 monitoring period. The line shows the North Carolina State
Standard of 5.0 mg/L and the dashed line shows the NC State Standard for
swampwater of 4.0 mg/L.
3.6 Cape Fear River Subbasin 03-06-19
Includes the Black River, Six Runs Creek and Great Coharie
Creek
Municipalities: Town of Clinton
LCFRP Station Codes (DWQ #): LCO (64), GCO (63), 6RC (65)
DWQ/UNCW ambient monitoring site(s): none
Waterbody: Little Coharie Creek, Great Coharie Creek and Six Runs Creek, all
flow to the Black River
Location: Sampson County
Lat/Lon: N 34 55.114 W 78 23.324 (GCO)
N 34 47.614 W 78 18.715 (6RC)
GCO
LCO
6RC
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
452.1 mi.
Partially Supporting:
15.0 mi.
Not Supporting:
0.0 mi.
Not Rated:
40.2 mi.
This subbasin is located in the coastal plain within Sampson County. Land
adjacent to the Black River is primarily undisturbed forest. There is a very high
concentration of hog farms within these watersheds. There are 7 permitted
dischargers, the largest of which is the Town of Clinton. (NCDENR, DWQ Cape
Fear River Basinwide Water Quality Plan, July 2000)
Stewarts Creek (15.0 miles from source to Six Runs Creek) is currently partially
supporting (PS) due to an impaired biological community. The Town of Magnolia
discharges into a tributary, which eventually flows to Stewarts Creek downstream
of Warsaw. The Magnolia WWTP has had problems with effluent toxicity and
has been fined monthly during violations. Stewarts Creek is the only stream in
the subbasin that is impaired and on the state’s year 2000 303(d) list. (NCDENR,
DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
Portions of Great Coharie Creek, Little Coharie Creek, Six Runs Creek and
Crane Creek were impacted during Hurricane Fran in 1996. These steams were
also subject to massive desnagging operations after the storm. Benthic
monitoring is recommended to determine the impacts of desnagging operations
that remove important habitat in these waters. (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan, July 2000).
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: LCO, GCO, 6RC
Data collection: February 1996 to present
Sampling relevance: Concentrated animal operations (CAOs) within
the watershed, reference areas for point and nonpoint source
pollution
GCO - blackwater
stream, drains
riparian wetlands in an
area with concentrated
animal operations
Little Coharie Creek (LCO) and Six Runs Creek (6RC) were found to be good
quality for dissolved oxygen (DO) concentrations, falling below the NC State
Standard of 5.0 mg/L only once in July 2002. Great Coharie Creek (GCO) was
rated as poor quality for dissolved oxygen concentrations, not meeting the
standard of 5.0 mg/L in 50% of sampled months. When reevaluated using the
swampwater standard of 4.0 mg/L, GCO was rated as fair quality, with only 2
samples below the 4.0 mg/L swampwater standard. The lowest values for DO at
GCO were in July 2002, measuring 2.6 mg/L, and September 2002, measuring
0.8 mg/L. The dissolved oxygen concentration values for GCO are represented
graphically in Figure 3.6.1.
All sites within this subbasin were found to be good quality for chlorophyll a
concentrations, fecal coliform bacteria concentrations and turbidity
concentrations.
Nutrient loading, especially total phosphorus (TP) was a problem at GCO
(Figures 3.6.2). In September of 2002 TP levels were 1,400 g/L, and average
concentrations for the sampling period were 373 g/L. These levels were far
above the concentrations known to lead to ATP increases, bacterial increases
and increased biochemical oxygen demand (BOD) in blackwater streams (Mallin
et al. 2001, Mallin et al. 2002).
Dissolved Oxygen Concentrations (mg/L)
for 2002-2003 monitoring period
Dissolved Oxygen (mg/L)
12.0
10.0
GCO
8.0
6.0
4.0
2.0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
JUL
0.0
Figure 3.6.1 Dissolved oxygen concentrations (mg/L) for GCO during the 20022003 monitoring period. The line shows the NC State Standard for dissolved
oxygen of 5.0 mg/L, and the dashed line shows the NC State Standard for
swampwater of 4.0 mg/L.
1600
1400
1200
1000
800
600
400
200
0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
GCO
JUL
Total Phophorus ( g/L))
Total Phosphorus (g/L) for the 2002-2003
monitoring period
Figure 3.6.2 Total phosphorus concentrations (g/L) for GCO during the
2002-2003 monitoring period.
3.7 Cape Fear River Subbasin 03-06-20
Includes the Black River, Colly Creek and Moores Creek
Municipalities: Town of White Lake, Currie and Atkinson
LCFRP Station Codes (DWQ #): COL (68), B210 (70), BBT
DWQ/UNCW ambient monitoring site(s): none
Waterbody: Creeks that drain into the Black River, draining swamp areas
Location: Pender County, tributaries of the Black River, before confluence with
the Lower Cape Fear River
Lat/Lon: N 34 27.900 W 78 15.392 (COL) to
N 34 21.086 W 78 02.956 (BBT)
B210
COL
BBT
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
142.5 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
0.0 mi.
Not Rated:
35.7 mi.
This subbasin is located in the coastal plain in Pender County. The only
permitted discharger within the subbasin is White Lake WWTP. The
characteristics of streams in this area are typically: low geographic relief, low pH
blackwaters, and a tendency for all but the largest rivers to stop flowing in the
summer. The Black River in this area has been classified as Outstanding
Resource Waters (ORW). (NCDENR, DWQ Cape Fear River Basinwide Water
Quality Plan, July 2000)
Agriculture is the major land use, and nonpoint source pollution is a major
problem throughout the subbasin, especially the tributaries. Biological rating
resulted in no streams being classified as impaired. The water quality of this
subbbasin appears to be generally good. Due to the lack of flow in summer
months, DWQ water quality monitoring assessments of tributaries were based on
winter sampling. (NCDENR, DWQ Basinwide Water Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: COL, B210, BBT
Data collection: February 1996 to present
Sampling relevance: Colly Creek is pristine swamp reference site,
B210 and BBT are middle and lower Black River sites
COL – blackwater,
stream, drains
large swamp area
B210 - Black River, where
Hwy 210 bridge passes
over
Colly Creek was found to be good quality for dissolved oxygen concentrations.
B210 was rated as fair quality if measured by the NC State Standard of 5.0 mg/L,
not meeting the standard in 25% of sampled months. B210 was good quality for
dissolved oxygen if measured by the swampwater standard of 4.0 mg/L. BBT
was rated as poor quality if using the 5.0 mg/L standard, but found to be good
quality if measured by the swampwater 4.0 mg/L standard. This area is affected
by swampwater inputs and may have lower dissolved oxygen concentrations as
a result of these inputs.
Chlorophyll a concentrations were all low for the sites within this subbasin. All
stations were found to be good quality for chlorophyll a. No sample exceeded
the 40 g/L North Carolina State Standard.
Fecal coliform bacteria concentrations were generally low, and COL and B210
were good quality. BBT samples were not analyzed for fecal coliform bacteria.
All three sites were found to be good quality for turbidity levels, not exceeding the
North Carolina State Standard of 50 NTU.
3.8 Cape Fear River Subbasin 03-06-21
Includes the Northeast Cape Fear River and Barlow Branch
Municipalities: Mount Olive
LCFRP Station Code (DWQ#): NC403 (94)
DWQ/UNCW ambient monitoring site(s): NC403
Waterbody: Northeast Cape Fear River
Location: NC Hwy 403, on the borders of Wayne and Duplin County
Lat/Lon: N 35 10.703 W 77 58.817 (NC403)
NC403
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
69.3 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
4.3 mi.
Not Rated:
6.8 mi.
Significant dischargers in this subbasin are Mount Olive Pickle Company and the
Town of Mount Olive. DWQ biological assessment sampling resulted in no
impaired rating for streams in this subbasin.
Portions of the Northeast Cape Fear River and Barlow Branch were identified as
impaired in the 1996 Basinwide Water Quality Plan. The discharge from Mount
Olive Pickle Company was the cause of impairment. Chloride levels exceeded
the water quality limit in 48% of the samples from 1993 to July 1996, at Northeast
Cape Fear River at SR 1937 approximately 2.7 miles from discharge source.
The ambient water quality station was relocated approximately 5.1 miles
downstream in 1996 to the NC403 site. The ambient station data at NC 403 has
not indicated high chloride levels. Currently the Northeast Cape Fear River (3.3
miles from source to SR 1937) and Barlow Branch (1 mile) are not supporting
(NS). (NCDENR, DWQ, Cape Fear River Basinwide Water Quality Plan, July
2000)
The Mount Olive Pickle Company discharges chlorides above permitted levels
into Barlow Branch before it joins the Northeast Cape Fear River. The Mount
Olive Pickle Company was given a variance from the state surface water quality
standard for chloride (230mg/L) in 1996. They have met the requirements of the
variance to date, and have reduced water usage and salt usage. (NCDENR,
DWQ, Cape Fear River Basinwide Water Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Name: NC403
Data collection: June 1997 – present
Sampling relevance: Below Mount Olive Pickle Plant
NC403 - slow moving creek
The NC403 site was found to be poor quality for dissolved oxygen
concentrations, not meeting the NC State Standard of 5.0 mg/L in 67% of all
samples. Even when using the NC swampwater standard of 4.0 mg/L, NC403
was found to be poor quality, not meeting the standard 58% of the time. For July
- October 2002, and May - June 2003 the dissolved oxygen levels were equal or
less than 1.0 mg/L. The mean for the 2002-2003 sampling period was 3.4 mg/L.
The dissolved oxygen concentrations are represented graphically in Figure 3.8.1.
For biological standards, NC403 was found to be good quality in terms of
chlorophyll a and fecal coliform bacteria concentrations. Extensive aquatic
macrophyte vegetation characterizes this site.
NC403 was found to be good quality for turbidity, with samples not exceeding the
standard of 50 NTU during the 2002-2003 monitoring period.
UNCW researchers are concerned that elevated nutrient levels are periodically
found at this site. Nitrate-N concentrations >500 g/L occurred several times at
NC403 during the 2002-2003 monitoring period, levels that can cause algal
blooms. High total phosphorus (TP) concentrations occur at times (>500 g/L),
which UNCW scientists find can stimulate increased biochemical oxygen demand
(BOD) and lead to lower dissolved oxygen levels (Mallin et al. 2002). Nutrient
concentrations are shown graphically for NC403 in Figure 3.8.2.
10.0
8.0
6.0
4.0
2.0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0.0
JUL
Dissolved Oxygen (mg/L)
Dissolved Oxygen Concentrations (mg/L)
at NC403 for the 2002-2003 monitoring period
Figure 3.8.1 Dissolved oxygen concentrations (mg/L) at NC403 for the 20022003 monitoring period. The line shows the NC State Standard of 5.0 mg/L and
the dashed line shows the swampwater standard of 4.0 mg/L.
1800
1600
1400
1200
1000
800
600
400
200
0
Nitrate-Nitrite
Total Phosphorus
JUL
AUG
SEP
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
Concentration ( g/L)
Nutrient Concentrations (g/L) for NC403
for the 2002-2003 monitoring period
Figure 3.8.2 Nutrient concentrations (g/L) at NC403 for the 2002-2003
monitoring period.
3.9 Cape Fear River Subbasin 03-06-22
Includes the Northeast Cape Fear River and Rockfish Creek
Municipalities: Beulaville, Kenansville, Rose Hill and Wallace
LCFRP Station Codes (DWQ #): PB (77), GS (78), SAR (79), LRC (80), ROC
(81)
DWQ/UNCW ambient monitoring site(s): none
Waterbody: Northeast Cape Fear River
Location: Duplin County
Lat/Lon: N 35 08.067 W 78 08.178 (PB) to
N 34 43.035 W 77 58.763 (ROC)
PB
GS
SAR
LRC
ROC
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
283.3 mi.
Partially Supporting:
22.7 mi.
Not Supporting:
0.0 mi.
Not Rated:
208.2 mi.
This subbasin contains the towns of Beulaville, Kenansville, Rose Hill, and
Wallace. Most of the watershed is agricultural, including row crops and a dense
concentration of animal operations (poultry and swine). The largest discharger is
Stevecoknit Fabrics. Other large dischargers include Guilford Mills, SwiftEckrich/Butterball and the town of Wallace. (NCDENR, DWQ, Cape Fear River
Basinwide Water Quality Plan, July 2000)
Goshen Swamp and Panther Creek were not supporting (NS) in the 1996 plan
because of high chloride discharge from Dean Pickle and Specialty Products.
Discharge flows into a low flow tributary of Panther Creek before entering
Goshen Swamp. Dean Pickle and Specialty Products was given a variance for
chloride levels and has met that variance to date. Goshen Swamp and Panther
Creek were not sampled during recent DWQ monitoring because of low flow
conditions. These two streams are currently not rated (NR). (NCDENR, DWQ,
Cape Fear River Basinwide Water Quality Plan, July 2000)
Rockfish Creek (7.2 miles SR 1165 to Northeast Cape Fear River) was partially
supporting (PS) in the 1996 plan. Currently, 8.7 miles (from Swift-Eckrich to Little
Rockfish Creek) are partially supporting (PS) because of habitat degradation.
The 3.8-mile segment from Little Rockfish Creek to the Northeast Cape Fear
River is fully supporting (FS). Desnagging operations after Hurricane Fran
removed important habitat for macroinvertebrates and fish in these waters. Point
source dischargers may contribute to the habitat degradation. These waters are
on the state’s year 2000 303(d) list. (NCDENR, DWQ, Cape Fear River
Basinwide Water Quality Plan, July 2000)
Muddy Creek (14.0 miles from the source to Northeast Cape Fear River) was not
rated in 1993 because of its small size. The stream is significantly larger due to
changes associated with Hurricane Fran in 1996. The stream is partially
supporting (PS) according to recent DWQ monitoring due to nonpoint sources.
The watershed contains many hog operations. This stream is on the state’s year
2000 303(d) list. (NCDENR, DWQ, Cape Fear River Basinwide Water Quality
Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: PB, GS, SAR, LRC, ROC
Data collection: February 1996 to present
Sampling relevance: Below point and nonpoint source discharges
PB - Panther Branch,
below
Products
Dean Pickle and Specialty
ROC - Rockfish Creek,
downstream of Wallace
Two sites within this subbasin, Little Rockfish Creek (LRC) and Rockfish Creek
(ROC) were found to be good quality in terms of dissolved oxygen
concentrations. Two sites, Panther Branch (PB) and Sarecta (SAR) were found
to be fair quality, not meeting the 5.0 mg/L standard 25% of the time. PB was
found to be fair quality if measured by the swampwater standard of 4.0.mg/L, not
meeting the standard 25% of the time. SAR was considered good quality if
measured by the 4.0 mg/L swampwater standard. One site, Goshen Swamp
(GS) was found to be poor quality for dissolved oxygen, not meeting the standard
of 5.0 mg/L 42% of the time. Even when considering this site with the
swampwater standard of 4.0 mg/L, it is found to be poor quality, not meeting the
standard 33% of the time. Samples for GS from July - October 2002 were all
less than 3.0 mg/L, with the lowest concentration reported in October of 0.7
mg/L. The dissolved oxygen concentrations for GS are shown graphically in
Figure 3.9.1.
Most sites within this subbasin were found to be good quality for chlorophyll a
concentrations. The exception is Panther Branch (PB), which was found to be
fair quality, exceeding the NC State Standard of 40 g/L 17% of the time.
For fecal coliform bacteria concentrations, all sites within this subbasin were
found to be fair quality. PB, SAR and ROC all exceeded the NC State Standard
for human contact of 200 CFU/100mL in 17% of sampled months. GS and LRC
were also rated as fair quality, both exceeded the standard 25% of the time. The
highest levels for most sites were found in September and December 2002.
Fecal coliform bacteria concentrations are shown graphically for GS and LRC in
Figure 3.9.2.
All sites were found to be good quality for turbidity concentrations. Mean turbidity
levels were less than 20 NTU for all sites within this subbasin for the 2002-2003
monitoring period.
Stations PB and ROC both displayed high total phosphorus concentrations
(Figure 3.9.3). High phosphorus levels are known to significantly increase
bacterial concentration and biochemical oxygen demand (BOD) levels. Stations
PB, SAR and ROC had elevated levels of nitrate+nitrite at times (Figure 3.9.4).
High nitrate levels have been known to lead to algal bloom formation (Mallin et al.
2001, Mallin et al. 2002).
18
PB
GS
SAR
16
14
12
10
8
6
4
2
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0
JUL
Dissolved Oxygen (mg/L)
Dissolved Oxygen Concentrations (mg/L)
for the 2002-2003 monitoring period
Figure 3.9.1 Dissolved oxygen concentrations (mg/L) for the 2002-2003
monitoring period. The line shows the NC State Standard for dissolved oxygen
of 5.0 mg/L and the dashed line shows the swampwater standard of 4.0 mg/L.
Fecal Coliform Bacteria Concentrations (CFU/100mL)
for the 2002-2003 monitoring period
1,800
(CFU/100mL)
1,600
GS
LRC
1,400
1,200
1,000
800
600
400
200
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
JUL
0
Figure 3.9.2 Fecal coliform bacteria concentrations (CFU/100mL) for the 20022003 monitoring period. The line shows the NC State Standard for human
contact waters of 200 CFU/100mL.
1,600
1,400
1,200
1,000
800
600
400
200
0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
PB
ROC
JUL
Total Phosphorus (g/L)
Total Phosphorus (g/L) for the
2002-2003 monitoring period
Figure 3.9.3 Total phosphorus concentrations (g/L) for the 2002-2003
monitoring period.
Nitrate+Nitrite (g/L)
Nitrate+Nitrite ( g/L) for
the 2002-2003 monitoring period
5000
SAR
PB
ROC
4000
3000
2000
1000
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
JUL
0
Figure 3.9.4 Nitrate-Nitrite concentrations (g/L) for the 2002-2003 monitoring
period.
3.10 Cape Fear River Subbasin 03-06-23
Includes the Northeast Cape Fear River and Burgaw Creek
Municipalities: Town of Burgaw
LCFRP Station Codes (DWQ #): ANC (69), BCRR (82), BC117 (83), NCF117
(84), NCF6 (85)
DWQ ambient monitoring site(s): NCF117
Waterbody: Northeast Cape Fear and tributaries
Location: Pender and New Hanover Counties
Lat/Lon: N 34 39.423 W 77 44.091 (ANC)
N 34 19.026 W 77 57.230 (NCF6)
BCRR
BC117
ANC
NCF117
NCF6
Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water
Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
304.1 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
14.3 mi.
Not Rated:
37.5 mi.
This subbasin is located in the outer coastal plain and contains the Town of
Burgaw. Most streams in this area are slow flowing blackwater streams, and
many dry up or stop flowing during the summer. Much of the subbasin is
undeveloped and included in either the Holly Shelter Game Refuge or the Angola
Bay Game Refuge. (NCDENR, DWQ Cape Fear River Basinwide Water Quality
Plan, July 2000)
There are six permitted dischargers in the subbasin, with the largest dischargers
being Occidental Chemical, Thorn Apple Valley, and Burgaw WWTP. Ambient
chemistry data show average nutrient levels in the Northeast Cape Fear River at
US 117 to be lower than more upstream river sites. Biological rating resulted in
impaired ratings for four of the seven stream segments. Benthic
macroinvertebrate data showed fairly stable water quality for most of the
subbasin, exceptions include Burgaw Creek below WWTP, and Burnt Mill Creek
in Wilmington, both of which were rated poor. (NCDENR, DWQ Cape Fear River
Basinwide Water Quality Plan, July 2000)
Portions of Burnt Mill Creek and Burgaw Creek are currently rated as impaired
according to recent DWQ monitoring. Burnt Mill Creek (4.8 miles from source to
Smith Creek) was not supporting (NS) in the 1996 plan and is currently not
supporting (NS) because of impaired biological community. Instream habitat
degradation associated with urban nonpoint sources and channel dredging is a
possible cause of impairment. This stream is on the state’s year 2000 303(d) list.
(NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
Burgaw Creek (9.5 miles from Osgood Canal to the Northeast Cape Fear River)
was not supporting (NS) in the 1996 plan, and is currently non-supporting (NS)
due to impaired biological community. Instream habitat degradation associated
with urban nonpoint sources is a possible cause of impairment. There are
indications of excessive nutrients in this stream, and fecal coliform bacteria are
also noted as a problem parameter. Failing septic systems have been noted in
this watershed as well. The stream is channelized and has been adversely
impacted by desnagging activities after Hurricane Fran. This stream is on the
state’s year 2000 303(d) list. (NCDENR, DWQ Cape Fear River Basinwide
Water Quality Plan, July 2000)
UNC-Wilmington – Center for Marine Science, LCFRP
Station Names: ANC, BCRR, BC117, NCF117, NCF6
Data collection: NCF117 & NCF6 since June 1995, all others since
February 1996
Sampling relevance: point and nonpoint source dischargers
ANC - Angola Creek, swamp
reference
site, tributary of the Northeast
Cape Fear River
BC117 - Burgaw Canal at
US 117, downstream of
Burgaw WWTP
NCF117 - Northeast Cape Fear
River at
at US117, also a DWQ ambient
site
Almost all sites within this subbasin were rated as poor quality in terms of
dissolved oxygen concentrations. BC117 was the exception, rated as fair quality,
and not meeting the 5.0 mg/L standard in 17% of sampled months. NCF117 and
NCF6 were both found to be poor quality, not meeting the standard in 33% of
samples. BCRR was found to be poor quality, not meeting the standard 42% of
the time. ANC was also found to be poor quality, not meeting the standard 58%
of the time. In five of the twelve sampled months, dissolved oxygen
concentrations were less than 1.0 mg/L at ANC. All sites were also rated using
the NC swampwater standard of 4.0 mg/L. BC117, NCF117 and NCF6 were
rated good quality for dissolved oxygen concentrations, and ANC and BCRR
would still be poor quality, not meeting the 4.0 mg/L standard in 42% of sampled
months. The dissolved oxygen concentrations are shown graphically for the four
sites found to be poor quality in Figure 3.10.1.
All sites in this subbasin were found to be good quality in terms of chlorophyll a
concentrations. Mean for the 2002-2003 monitoring period were all less than 10
g/L, well below the NC State Standard of 40 g/L.
Two sites, NCF117 and NCF6 were found to be good quality for fecal coliform
bacteria concentrations. Two sites, ANC and BCRR were found to be fair quality,
exceeding the human contact water (200 CFU/100mL) standard 25% of the time.
One site, BC117 was found to be poor quality, exceeding the standard 42% of
the time. The geomean for BC117 for the 2002-2003 monitoring period was 195
CFU/100mL, with the highest concentrations of 1430 CFU/100mL found in
December 2002. Fecal coliform bacteria concentrations for ANC, BCRR and
BC117 are shown graphically in Figure 3.10.2.
All sites within this subbasin were found to be good quality for turbidity. The
mean value for all stations and all months for this subbasin for the 2002-2003
monitoring period was 11 NTU.
Nutrient loading, especially of nitrate-N and total phosphorus (TP) was a severe
problem at BC117 (Figures 3.10.3 and Figure 3.10.4). Both nitrate-N and TP
were the highest 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 and ANC also periodically experienced
elevated nutrient levels as well.
UNCW also samples Burnt Mill Creek as part of the Wilmington Watersheds
Program. Our data show excessive fecal coliform bacteria concentrations, low
dissolved oxygen levels, and high sediment metal concentrations. These data
are available in hardcopy from Dr. Michael Mallin and also online in report format
at this website:
http://www.uncwil.edu/cmsr/aquaticecology/TidalCreeks/Index.htm
14
12
10
ANC
BCRR
NCF117
NCF6
8
6
4
2
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0
JUL
Dissolved Oxygen (mg/L)
Dissolved Oxygen (mg/L) for
the 2002-2003 monitoring period
Figure 3.10.1 Dissolved oxygen concentrations (mg/L) for the 2002-2003
monitoring period. The line shows the NC State Standard of 5.0 mg/L and the
dashed line shows the swampwater standard of 4.0 mg/L.
1,600
1,400
1,200
1,000
800
600
400
200
0
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
ANC
BCRR
BC117
JUL
Fecal Coliform Bacteria
(CFU/100mL)
Fecal Coliform Bacteria (CFU/100mL)
for the 2002-2003 montoring period
Figure 3.10.2 Fecal coliform bacteria concentrations (CFU/100mL) for the
2002-2003 monitoring period. The line shows the NC State Standard for human
contact waters of 200 CFU/100mL.
20,000
15,000
BC117
10,000
5,000
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0
JUL
Nitrate+Nitrite (g/L)
Nitrate+Nitrite (g/L) for the
2002-2003 monitoring period
Figure 3.10.3 Nitrate-nitrite concentrations (g/L) for BC117 for the 2002-2003
monitoring period.
5,000
BC117
4,000
3,000
2,000
1,000
JUN
MAY
APR
MAR
FEB
JAN
DEC
NOV
OCT
SEP
AUG
0
JUL
Total Phosphorus (g/L)
Total Phosphorus (g/L) for
the 2002-2003 monitoring period
Figure 3.10.4 Total phosphorus concentrations (g/L) for BC117 for the 20022003 monitoring period.
3.11 Summary of all Stations
Table 3.11.1 UNCW ratings of sample stations in the Lower Cape Fear River
Program, based on July 2002 - June 2003 monitoring data.
G (good quality) – standard exceeded in < 10% of the measurements
F (fair quality) – standard exceeded in 11-25% of the measurements
P (poor quality) – standard exceeded in > 25% of the measurements
Subbasin Station
03-06-16 BRN
HAM
NC11
03-06-17 LVC
AC
DP
IC
NAV
HB
BRR
M61
M54
M42
M35
M23
M18
SPD
03-06-18 SR
03-06-19 LCO
GCO
6RC
03-06-20 COL
B210
BBT
03-06-21 N403
03-06-22 PB
GS
SAR
LRC
ROC
03-06-23 ANC
BCRR
BC117
NCF117
NCF6
DO
G
P (33%)
G
F (17%)
G
F (25%)
F (17%)
P (33%)
F (25%)
F (17%)
F (25%)
F (17%)
G
G
G
G
F (25%)
P (42%)
G
P (50%)
G
G
F (25%)
P (33%)
P (67%)
F (25%)
P (42%)
F (25%)
G
G
P (58%)
P (42%)
F (17%)
P (33%)
P (33%)
Swamp
DO
F (25%)
P (33%)
F (17%)
G
G
P (58%)
F (25%)
P (33%)
G
P (42%)
P (42%)
G
G
G
Chl a
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
F (17%)
G
G
G
G
G
G
G
G
G
Fecal
Coliforms*
F (25%)
P (33%)
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
F (25%)
G
G
G
G
G
no sample
G
F (17%)
F (25%)
F (17%)
F (25%)
F (17%)
F (25%)
F (25%)
P (42%)
G
G
Turbidity
G
G
G
G
P (42%)
P (33%)
G
P (33%)
G
G
G
G
G
F (17%)
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
Excessive
Nutrients
TP
TP & Nitrate-N
TP & Nitrate-N
Nitrate-N
TP & Nitrate-N
TP
TP & Nitrate-N
*Fecal coliform bacteria rating system is based on the human contact standard of
200 CFU/100mL, not the shellfishing standard of 14 CFU/100mL
3.12 References Cited
Cape Fear River Basinwide Water Quality Plan. July 2000. North Carolina
Department of Environmental and Natural Resources (NCDENR), Division of
Water Quality (DWQ) Section, Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001. Effect of
nitrogen and phosphorus loading on plankton in Coastal Plain blackwater
streams. Journal of Freshwater Ecology 16:455-466.
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.
4.0 BOD Concentrations, Loading, and Sources in the
Lower Cape Fear River System
by
Michael A. Mallin
Center for Marine Science
University of North Carolina at Wilmington
Wilmington, NC 28409
4.1 Abstract
An examination of river and stream biochemical oxygen demand (BOD) was conducted
over a five-year period in the lower Cape Fear River system, in coastal North Carolina.
Median BOD5 was approximately 1.1 mg/L in the Piedmont-derived sixth order Cape
Fear River and slightly lower in the two fifth order blackwater tributaries, the Black and
Northeast Cape Fear Rivers. BOD in the Cape Fear River was most strongly correlated
with chlorophyll a, whereas in the two blackwater tributaries BOD was most strongly
correlated with phosphorus concentrations and fecal coliform bacterial counts. This
relationship may be a result of nutrient induced increases in heterotrophy, as previous
experimental studies have shown that phosphorus additions to blackwater streams lead
directly to increased bacterial counts and BOD concentrations. BOD load as lbs
BOD/day was correlated much more strongly with river discharge than BOD
concentration in all three rivers, with discharge alone able to explain from 40-80% of
BOD load variability, depending upon the system. A set of second-to-third order rural
streams in the Black River basin was also examined. Median BOD5 concentrations
ranged from 0.9-1.2 mg/L in all six tributaries, regardless of land use and watershed
size. BOD load varied directly with stream flow. In contrast, BOD5 and BOD20
concentrations in three urban streams in Wilmington, N.C. were approximately double
those of the rural streams, with much higher storm event maxima in the urban
situations.
4.2 Introduction
The North Carolina Division of Water Quality (NCDWQ 2000) has indicated that the
lower Cape Fear River and its estuary is impaired by low dissolved oxygen (DO). Thus,
the NCDWQ is requiring a TMDL (total maximum daily load) for biochemical oxygen
demand (BOD). Research has confirmed that low DO (between 3 and 5 mg/L) is
common in the lower river and estuary during June through September (Mallin et al.
1999; 2002a). Over the past several years the Lower Cape fear River Program has
performed a number of BOD related studies to help in understanding the magnitude of
this problem and potential sources of BOD.
The Cape Fear River system is a depository for numerous NPDES dischargers, which
are point sources of treated effluent into the system (NCDWQ 2000). Point sources are
permitted by the NC Division of Water Quality to release a prescribed amount of BOD
into the system through their discharges, and are required to report actual amounts
discharged. Besides these point sources, BOD may also enter the system through non-
point source runoff from agricultural sources such as swine waste lagoon spray field
sites, areas where poultry manure is spread, and cattle pastures. Another potential
source is natural BOD from organic materials in riparian swamps that flow into the river
via tributary streams. Finally, the Cape Fear River receives urban runoff from a number
of municipalities and thus non-point source runoff from urban and suburban streams is
also a source of BOD to the system.
The Lower Cape Fear River Program (LCFRP) has been collecting BOD data since
February 1996. Using these data we describe the seasonal and spatial BOD loads that
come into the lower system from the upper and middle Cape Fear watersheds, and the
two major blackwater tributaries. The blackwater tributaries drain extensive agricultural
areas, and point source discharges are relatively low in volume in these watersheds.
Thus, a significant amount of BOD loading to the system is may be derived from nonpoint sources. However, there is currently no published information available on the
variability of BOD loading to the system from non-point sources. Estimating BOD loads
requires both assessment of BOD concentrations in the water and computation of
stream flow at the time of analysis. During the period May 2000 through June 2003 we
collected monthly BOD and streamflow data at six rural streams in the Black River
watershed. These collections were made on a pre-set schedule, so they are not storm
event samples, but primarily represent base flow conditions. Additionally, the City of
Wilmington is funding the Wilmington Watersheds Program, under which the UNC
Wilmington Aquatic Ecology Laboratory collects water quality information on urban and
suburban watersheds. As a part of this effort we collected BOD data on three urban
and suburban streams draining into the Cape fear estuary near the City of Wilmington.
4.3 Materials and Methods
We collected water samples by boat on a monthly basis at six locations in the LCFR
system (Fig. 1.1). These sites were the Cape Fear River at Highway NC11 (to measure
BOD loads entering the lower CFR mainstem from the Piedmont and upper Coastal
Plain); AC (to measure BOD in the mainstem downstream of inputs from a pulp and
paper mill on the Cape Fear River and dischargers on Livingston Creek); LVC (to
measure BOD in lower Livingston Creek); the Northeast Cape Fear River at Highway
117 (NCF117 - to measure BOD loads from the upper Northeast Cape Fear River
basin); the Black river at Highway 210 (B210 - to measure BOD loads from the upper
Black River system); and BBT (to measure BOD in the lower Black River that is also
influenced by the mainstem CFR via the channel known as Thoroughfare). Samples
were collected by hand in acid-cleaned 1L plastic bottles and stored on ice for transport
to the laboratory. Data collected during the five-year period from July 1998 through
June 2003 are presented within.
Laboratory analyses for BOD followed APHA (1995). In the laboratory, a warm-water
bath was used to raise the temperature of the 1L bottles to 20o C. Samples were then
aerated by rapid mixing to ensure adequate initial dissolved oxygen of the sample
water. Duplicate 300 mL BOD bottles were filled with sample water, and air bubbles
were removed from the shoulder of the bottles by tapping them with an acrylic BOD
bottle stopper. Samples were incubated for 20 days at 20.0o C. Dissolved oxygen was
read at the time of setup, day 5, and day 20 using a YSI 57 also recorded at setup, day
5, and day 20. BOD5 and BOD20 measurements (as mg/L BOD) were calculated by
subtracting dissolved oxygen on day 5 and 20, respectively, from the initial dissolved
oxygen.
Daily river discharge data was obtained from the U.S. Geological Survey for the three
main river branches. The flow gauging stations are located at Lock and Dam #1 on the
Cape Fear mainstem, near Tomahawk on the Black River, and near Chinquapin on the
Northeast Cape Fear River. Average river discharge for each month from July 1998
through June 2003 was converted from CFS to CF/day. BOD (converted from mg/L to
lbs/ft3) and flow measurements were then multiplied to obtain average monthly
estimates of BOD loading as lbs/day.
BOD and BOD loading data for the three main tributary rivers were entered into a data
matrix along with a number of physical, chemical and biological variables collected with
the BOD samples, including water temperature, turbidity, total nitrogen (TN), nitrate-N,
ammonium, total phosphorus (TP), orthophosphate-P, chlorophyll a and fecal coliform
bacteria counts. River discharge data were included in the matrix, both as flow on the
day of collection and as average flow for the seven-day period preceding sampling.
Correlation and regression analyses were performed using SAS for each of the three
main tributaries to assess major factors influencing BOD and BOD load over the fiveyear period July 1998 through June 2003.
During the period May 2000 - June 2003, samples were collected monthly from the
following second and third order streams: Colly Creek (COL), Great Coharie Creek
(GCO), Little Coharie Creek (LCO), Hammond Creek (HAM), Browns Creek (BRN), and
Six Runs Creek (6RC). COL, GCO, LCO and 6RC are located in the Black River Basin
and HAM and BRN empty into the mainstem of the Cape Fear River (Fig. 1.1). A
bucket and rope were used to collect water mid-stream from a bridge. Acid-cleaned 1L
plastic bottles were filled from the bucket and stored on ice for transport to the
laboratory.
For the stream stations flow was measured mid-stream from a bridge using a MarshMcBirney Flo-Mate Model 2000. A lead weight and fin apparatus were used to keep the
flow sensor motionless in the water column and pointed into the current. Flow data
were obtained as m/s. A lead line with 0.5 m gradations was used to measure depth at
3 m intervals across the stream. From these measurements average depth was
computed. Average depth was multiplied by stream width to obtain the cross-sectional
area of the creek in m2. Volume of flow was calculated by multiplying flow by crosssection area of the stream to obtain m3/s, subsequently converted to m3/day. BOD5
and BOD20 were converted to lbs BOD/m3, and multiplied by daily flow. BOD loading
was computed as lbs BOD/day.
Additional BOD data were collected from three urban and suburban streams, as a part
of the Wilmington Watersheds Program (Mallin et al. 2003). Smith Creek drains into the
Northeast Cape Fear River just upstream of the City of Wilmington, and Barnards and
Motts Creeks drain into the Cape Fear Estuary downstream of the Wilmington port area.
Smith Creek was sampled from the Castle Hayne Road bridge, and Barnards and Motts
Creeks were sampled from bridges on River Road, using the bucket technique as
described above. Data presented here are from February 2001 through April 2003.
Flow data from these three stations are not available.
4.4 Results and Discussion
BOD Concentrations - Spatial Comparisons
During the five-year period from July 1998 through June 2003, BOD among the major
tributaries of the lower Cape Fear River system showed little variability (Table 4.1).
Median BOD5 of the water entering the lower system at Station NC11 was 1.1 mg/L,
slightly higher than that of the two blackwater tributaries, the Black and Northeast Cape
Fear Rivers (Table 4.1). Between NC11 and AC, located about two miles downstream
of International Paper (IP), BOD5 and BOD20 concentrations increased of about 27%
and 31%, respectively. This increase was either due to inputs from IP, Livingston
Creek, or some combination of the two sources. BOD5 and BOD20 in Livingston Creek
are both 30-34% higher than water from NC11. However, Livingston Creek has been
sampled only about 50 m up from the mouth; thus, at times this station receives
significant inputs of water from the river channel. Median ratios of BOD20 to BOD5
varied from a low of 2.6 at NC11 to a high of 3.1 at LVC.
Peak BOD concentrations were generally found during or following rain events and
subsequent runoff episodes. In the main Cape Fear River channel the BOD5 maximum
of 2.4 mg/L occurred in February 2001, under moderate flow conditions (Fig. 4.1). The
BOD20 maximum of 8.6 mg/L occurred in December 2000, under conditions of
relatively low flow (Fig. 4.1). However, peak BOD5 and BOD20 concentrations at AC,
BBT, B210 and NCF117 all occurred in September 1998, following Hurricane Bonnie.
This hurricane impacted the Northeast Cape Fear and Black River watersheds in
particular, with little effect in the Piedmont (Mallin et al. 2002a).
Area of origination did not have a major influence on long-term BOD (BOD20)
compared with BOD5. The ratio of BOD20 to BOD5 in the Black and Northeast Cape
Fear Rivers was 2.9 in both cases; at BBT it was 2.8 and at Livingston Creek
(blackwater stream) it was 3.1. At NC11 it was 2.6 and at AC it was 2.7, indicating that
the blackwater influence provided somewhat more recalcitrant material to the load,
whereas the inputs from the upper and middle Cape Fear basins provided somewhat
more labile BOD.
BOD concentrations among the six stream stations showed little variability, despite
differences in discharge, watershed size, and land use. Median BOD5 among the
streams ranged from 0.9 - 1.2 mg/L, and median BOD20 ranged from 2.5 - 3.6 mg/L.
Mean values of both parameters were likewise in those ranges (Table 4.2). Median
ratios of BOD20 to BOD5 varied from a low of 2.5 at Browns Creek (BRN) to a high of
3.1 in Little Coharie Creek (LCO).
In contrast to the main river channels and the rural streams, the urban and suburban
streams yielded notably higher BOD concentrations (Table 4.3). Both BOD5 and
BOD20 yielded median and mean concentrations approximately twice those of the rural
stream sites. The maximum BOD5 values found in the urban streams were also twice
as high as the maximum values in the rural streams, whereas maximum BOD20 values
at the urban sites were 2-3 times as high as in the rural streams (Table 4.3). Median
BOD20 to BOD5 ratios varied from a low of 2.8 at Motts Creek to a high of 3.8 at
Barnards Creek.
BOD Loading to the Lower System
The mainstem of the Cape Fear River provided by far the largest BOD load to the lower
system, approximately 77% of the total (Fig. 4.2a). This load was considerably
increased by inputs from International Paper and Livingston Creek according to data
accumulated from Station AC (Fig. 4.2b). Median load increased by 37% at AC relative
to the upstream station NC11.
BOD loads in the Black and Northeast Cape Fear Rivers contributed relatively minor
(10% and 11%, respectively) amounts of total system BOD load compared with the
mainstem (Table 4.1). We were unable to compute a daily load at BBT due to lack of
accurate nearby river discharge data, but average BOD5 and BOD20 values at that
station fell between those at NC11 and AC (Table 4.1). BBT is in an area strongly
affected by tides, and also receives mainstem CFR BOD inputs via the channel known
as Thoroughfare.
There is a pronounced seasonal signal in BOD loading to the lower system (Fig. 4.2).
The data exhibit an annual winter-spring loading increase in all three main tributaries,
but especially so in the mainstem. This is likely due to a combination of factors. During
this period river flow is normally high due to the cooler weather and reduced
evapotranspiration. Increased river flow should bring about increased non-point source
runoff from agriculture and urban sources, as well as loading of decaying detrital matter
from riparian swamp forests. Also, there are occasional spring algal blooms in the
mainstem that die and subsequently contribute to the BOD load. Finally, because
cooler water holds more dissolved oxygen, many dischargers are permitted to increase
their BOD loads to the rivers in winter.
Peak loading rates occurred in different months than peak concentrations. At NC11
peak loadings of BOD5 and BOD20 were 150,921 and 409,643 lbs/day, respectively, in
April 2003, a month of very high river flow (Fig. 4.1). During that same month peak
loadings at AC of BOD5 and BOD20 were 237,162 and 625,244, respectively. In the
two major blackwater tributaries peak loadings were reached in September 1999,
following Hurricane Floyd. Maximum BOD5 and BOD20 loadings at B210 were 31,302
and 97,036 lbs/day, respectively, and maxima at NCF117 were 47,366 and 102,627
lbs/day, respectively. In addition, elevated BOD loading occurred following Hurricane
Bonnie in September 1998, especially in the blackwater tributaries. Thus, stream
discharge determined BOD loading more than BOD concentrations, at least at the
concentrations found in this study.
Probably the most realistic measure of the load is obtained by using the median. This
reduces the effect of data outliers (such as generated during hurricanes and droughts).
Between NC11 and AC the median increase is thus 9,060 lbs/day of BOD5. Discharger
self-reported data from International Paper shows that median rate of 4,169 lbs/day of
BOD5 originated from this industry from 1998-2003, or 46% of the BOD5 increase
between the two stations. Based on these figures, the other 54% of the BOD5
originated either from point sources in Livingston Creek and/or non-point sources in
Livingston Creek or the Cape Fear River.
BOD loading from the rural streams to the main river channels differed considerably,
ranging from a low of 33 lbs/day at Hammonds Creek to a high of 978 lbs/day at Six
Runs Creek (Table 4.2). This wide range was due to the broadly differing streamflow
regimes among these streams. In other words, the largest creeks such as 6RC, GCO,
LCO and COL had much greater BOD loading to the system than the small creeks such
as HAM and BRN.
Factors Associated with BOD
Correlation analyses indicated that BOD5 and BOD20 were positively correlated with
several factors (Table 4.4). At NC11 BOD5 was positively correlated with turbidity, fecal
coliform counts, and especially chlorophyll a, and BOD20 was positively correlated with
chlorophyll a only. The positive correlation between BOD5 and fecal coliform bacteria
may indicate that a portion of the BOD-producing materials are likely derived from the
same sources as fecal coliform bacteria, possibly livestock grazing areas, swine lagoon
spray fields, and/or human sewage effluents. Also, bacteria in general are
heterotrophs, using up dissolved oxygen during respiration, and fecal coliforms may
contribute to BOD in this manner (Mallin et al. 2002b). Turbidity was also strongly
correlated with fecal coliforms, indicating that non-point source runoff of wastes is an
important issue. Turbidity was also strongly correlated with river flow, indicating
upstream sedimentation problems and long-distance transport of turbidity. Dr. Lynn
Leonard of UNCW has analyzed turbidity particles from NC11 and indicated that these
particles are characteristic of the Piedmont and upper Coastal Plain. BOD5 and BOD20
loads were positively correlated with turbidity and fecal coliforms at NC11, as well as
with river flow on the day of sample collection and average river flow for the seven days
preceding sample collection at all three stations (Table 4.4). Water temperature was
inversely related to BOD load; this was likely a result of higher river discharge during the
cooler months. At NC11 BOD5 concentrations were weakly correlated with BOD5 loads
(r = 0.30, p = 0.02). The correlation between BOD load and river discharge was much
stronger, evidence that the rather low variability and ranges of BOD at this station do
not strongly affect BOD load, whereas river discharge does (Fig. 4.1).
The relatively strong correlation with chlorophyll a in the Cape Fear River at NC11 is
likely a result of algal biomass senescing in the BOD samples during incubation.
Nutrient addition bioassay experiments have demonstrated that nutrient inputs lead
directly to chlorophyll a increases in experimental chambers, and have the secondary
effect of causing significant BOD increases (Mallin et al. 2002b; Mallin et al. in press).
Strong positive correlations between phytoplankton biomass and BOD have also been
reported from Minnesota rivers (Heiskary and Markus 2001) as well as tidal creeks in
coastal North Carolina (MacPherson 2003). Median BOD5 in the Cape Fear River was
in the low range of the Minnesota rivers investigated by Heiskary and Markus (2001),
and the mean 2002-2003 chlorophyll a concentration in the Cape Fear River (4.3 mg/L)
was comparable to the chlorophyll a values in the Minnesota Rivers expressing BOD5
in the 1.0-1.2 mg/L range.
In the Black River, BOD5 showed a positive correlation with fecal coliforms, and a
positive correlation with orthophosphate as well. In Minnesota rivers, positive
correlations between BOD and phosphorus were reported from a number of systems
(Heiskary and Markus 2001). BOD20 was positively correlated with water temperature,
fecal coliform counts, orthophosphate, TP, and flow (Table 4.4). BOD5 and BOD20
loads were strongly correlated with river flow, but were not correlated with BOD
concentrations. In the Northeast Cape Fear River, both BOD5 and BOD20 were
significantly correlated with turbidity, fecal coliforms, orthophosphate, TP, and flow. In
this river, turbidity was also correlated with fecal coliform counts. BOD5 and BOD20
loads were strongly correlated with river flow, and also correlated with fecal coliforms,
orthophosphate, and TP (Table 4.4). In this river BOD concentrations were highly
significantly correlated with BOD loads (p < 0.001).
The lack of correlation between BOD concentration and chlorophyll a in the two
blackwater rivers is a result of the low phytoplankton biomass. The deep, well-mixed,
humic-stained waters retard phytoplankton growth (Mallin et al. 2001; Mallin et al. in
press). However, the positive correlations between phosphorus and BOD in these
blackwater streams are not surprising. Nutrient addition bioassay experiments have
demonstrated that additions of phosphorus, especially organic phosphorus, lead directly
to significant increases in BOD, ATP biomass, and bacterial abundance (Mallin et al.
2001; Mallin et al. 2002b; Mallin et al. in press). Phosphorus-induced increases in
bacterial abundance have been reported from salt marsh environments as well
(Sundareshwar et al. 2003).
Prediction of BOD concentration
Linear regression analyses were used to derive predictive equations for BOD5 and
BOD20 concentrations in the three main tributaries of the Cape Fear system (Table
4.5). For the Cape Fear River mainstem, models involving chlorophyll a along with
either turbidity or total phosphorus were the best predictors of BOD5, although neither
was able to account for more than 39% of the variability. The best predictors of BOD20
were models using these same two variables, although both accounted for only 19% of
the variability in BOD20 concentration (Table 4.5). The best predictive model for BOD5
in the Black River combined fecal coliform counts with TP, accounting for only 18% of
the variability. BOD20 in the Black River was best predicted by a model utilizing river
discharge on the sampling day along with TP, accounting for 25% of the variability in
BOD20 concentration (Table 4.5). In the Northeast Cape Fear River two models using
fecal coliform counts and either river discharge or TP both accounted for 67% of the
variability in BOD5. These same two variables best predicted BOD20 concentration,
with the discharge plus fecal coliform count model accounting for 66% of BOD20
variability and TP plus fecal coliform count model 61% of the variability (Table 4.5).
Prediction of BOD Load
The two components of BOD load are BOD concentration and stream discharge. River
discharge was strongly correlated to BOD in all three rivers, much more strongly than
BOD concentrations (Table 4.4; Fig. 4.1). We wanted to determine the extent that river
flow (a parameter that is measured continuously by USGS using instrumentation) could
be used, either alone or with other parameters, to predict BOD loading to the lower
Cape Fear Basin. We used linear regression analysis to evaluate such predictive
equations.
Regression modeling indicated that the best single-variable model for predicting BOD5
load arriving at NC11 involved river flow on the day of sample collection, accounting for
69% of the variability in BOD5 load. Adding variables to the model provided little more
predictive power; addition of turbidity increased the r2 to 71% (Table 4.6). River
discharge alone accounted for 79% of the variability in BOD20 load, with addition of
other variables providing negligible improvement to the model (Table 4.6). Models
using river discharge alone accounted for only 40% of the variability in both BOD5 and
BOD20 load in the Black River, with no improvement from addition of other variables
(Table 4.6). For the Northeast Cape Fear River, discharge alone accounted for 60% of
the BOD5 load variability with no further improvement from other variables. Discharge
alone accounted for 68% of the variability in BOD20 load, with addition of fecal coliform
counts marginally improving that to 71% (Table 4.6).
To summarize, river flow alone can be used to predict a substantial amount of the
variability in BOD load from the mainstem CFR and the Northeast Cape Fear River.
However flow alone or in combination with the other factors tested did not predict much
of the BOD load from the upper Black River. As noted, higher flow occurs in winter,
when larger amounts of BOD are permitted to be released by point source dischargers.
Also, greater river flow leads to greater non-point source inputs of BOD. The statistical
relationship between turbidity (an indicator of non-point source runoff) and fecal coliform
counts, and the correlation between BOD and fecal coliform counts both indicate a
strong non-point source BOD source in the Cape Fear River system.
Acknowledgments
For funding we thank the Lower Cape Fear River Program and the Water Resources
Research Institute of the University of North Carolina. Field and laboratory help was
provided by Scott Ensign, Virginia Johnson, Tara MacPherson, Matthew McIver, Doug
Parsons and Heather Wells. River flow data were provided by the U.S. Geological
Survey, Raleigh, N.C., and rainfall data were provide by the State Climate Office, North
Carolina State University, Raleigh. Robert Farmer of the North Carolina Division of
Water Quality provided us with NPDES discharger BOD data.
4.5 References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed.
American Public Health Association, Washington, D.C.
Heiskary, S. and H. Markus. 2001. Establishing relationships among nutrient
concentrations, phytoplankton abundance, and biochemical oxygen demand in
Minnesota, USA, rivers. Journal of Lake and Reservoir Management 17:251-267.
MacPherson, T.A. 2003. Sediment oxygen demand and biochemical oxygen demand:
patterns of oxygen depletion in tidal creek study sites. M.S. Thesis, the University of
North Carolina at Wilmington, Wilmington, NC. 55 pp.
Mallin, M.A., M.R. McIver, S.H. Ensign and L.B. Cahoon. Photosynthetic and
heterotrophic impacts of nutrient loading to blackwater streams. Ecological
Applications (In press).
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1999.
Alternation of factors limiting phytoplankton production in the Cape Fear Estuary.
Estuaries 22:985-996.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001. Effect of nitrogen and
phosphorus loading on plankton in Coastal Plain blackwater streams. Journal of
Freshwater Ecology 16:455-466.
Mallin, M.A., M.H. Posey, M.R. McIver, D.C. Parsons, S.H. Ensign and T.D. Alphin.
2002a. Impacts and recovery from multiple hurricanes in a Piedmont-Coastal Plain
river system. BioScience 52:999-1010.
Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002b. Seeking sciencebased 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., L.B. Cahoon, M.H. Posey, D.C. Parsons, V.L. Johnson, T.D. Alphin and
J.F. Merritt. 2003. Environmental Quality of Wilmington and New Hanover County
Watersheds, 2001-2002. CMS Report 03-01, Center for Marine Science, University of
North Carolina at Wilmington, Wilmington, N.C.
NCDENR. 2000. Cape Fear River Basinwide Water Quality Plan. North Carolina
Department of Environment and Natural Resources, Division of Water Quality, Water
Quality Section, Raleigh, NC, 27699-1617.
Sundareshwar, P.V., J.T. Morris, E.K. Koepfler and B. Forwalt. 2003. Phosphorus
limitation of coastal ecosystem processes. Science 299:563-565.
Table 4.1. Descriptive statistics of biochemical oxygen demand (BOD) collected at six
LCFRP river stations, July 1998 – June 2003.
______________________________________________________________________
BOD5
______________________________________________________________________
Creek
NC11
AC
LVC
BBT
B210
NCF117
______________________________________________________________________
Mean (mg/L) 1.2
1.6
1.4
1.2
0.9
1.0
SD
0.5
0.9
0.6
0.6
0.4
0.5
Minimum
0.6
0.5
0.6
0.6
0.4
0.4
Maximum
2.4
6.0
4.2
6.0
2.8
4.2
Median
1.1
1.4
1.3
1.1
0.8
0.9
Median
Flow (ft3/s)
2,992
2,992
525
510
Median
Load (lbs/d) 15,748
24,808
2,300
2,477
______________________________________________________________________
BOD20
______________________________________________________________________
Mean (mg/L) 3.2
4.4
4.0
3.3
2.5
2.8
SD
1.2
1.9
1.6
1.3
0.7
1.1
Minimum
1.8
1.9
1.8
1.7
1.3
1.2
Maximum
8.6
14.2
9.0
12.0
4.9
9.0
Median
2.9
3.8
4.0
3.1
2.3
2.6
Median
Load (lbs/d) 50,994
66,212
6,544
7,096
______________________________________________________________________
Table 4.2. Descriptive statistics of biochemical oxygen demand (BOD) collected at six
Black River basin stream stations, May 2000 – June 2003.
______________________________________________________________________
BOD5
______________________________________________________________________
Creek
6RC
LCO
GCO
BRN
HAM
COL
______________________________________________________________________
Mean (mg/L) 1.1
1.0
1.0
1.0
1.4
1.1
SD
0.5
0.5
0.7
0.4
0.7
0.8
Minimum
0.4
0.4
0.3
0.3
0.4
0.3
Maximum
2.4
2.3
3.6
2.4
3.4
3.5
Median
0.9
0.9
0.9
1.0
1.2
1.0
Median
Flow (m3/d) 434,160
422,064
494,208
20,736
9,504
Median
Load (lbs/d) 978
827
923
35
33
374,544
687
______________________________________________________________________
BOD20
______________________________________________________________________
Mean (mg/L) 2.9
3.0
3.1
2.7
3.6
2.9
SD
1.0
1.3
1.7
1.0
1.6
1.3
Minimum
1.6
1.2
1.2
1.4
1.2
1.2
Maximum
6.2
6.8
9.1
6.2
9.1
7.5
Median
2.7
2.8
2.7
2.5
3.6
2.7
2,480
3,003
86
79
1,844
Median
Load (lbs/d) 2,410
______________________________________________________________________
Table 4.3. Descriptive statistics of biochemical oxygen demand (BOD) collected at three
urban stream stations in the Cape Fear Estuary, February 2001 – April 2003.
______________________________________________________________________
BOD5
______________________________________________________________________
Creek
Smith Creek
Barnards Creek
Motts Creek
______________________________________________________________________
Mean (mg/L)
2.1
2.0
2.4
SD
1.3
1.3
1.8
Minimum
0.2
0.4
0.2
Maximum
5.5
6.1
7.9
Median
1.8
1.6
2.2
______________________________________________________________________
BOD20
______________________________________________________________________
Mean (mg/L)
7.1
7.4
7.0
SD
4.5
4.7
4.4
Minimum
2.4
2.5
2.2
Maximum
20.4
21.6
23.2
Median
5.8
6.0
6.1
______________________________________________________________________
Table 4.4. Correlation analyses between BOD and various physical and biological
parameters for the mainstem Cape Fear (NC11), Black (B210), and Northeast Cape
Fear (NCF117) Rivers, July 1998 - June 2003.
NC11
VARIABLE
BOD5
BOD5LOAD
BOD20
BOD20LOAD
TURB
____________________________________________________________________________
TEMP
-0.351
0.006
-0.378
0.003
TURB
0.285
0.030
0.707
0.001
0.679
0.001
1.000
0.0
FC
0.257
0.049
0.315
0.015
0.300
0.021
0.583
0.001
CHLORA
0.525
0.001
0.368
0.004
FLOW
0.831
0.001
0.888
0.001
0.723
0.001
FLOW7
0.625
0.001
0.690
0.001
0.260
0.046
B210
VARIABLE
BOD5
BOD5LOAD
BOD20
BOD20LOAD
TURB
____________________________________________________________________________
TEMP
0.343
0.008
FC
0.329
0.010
0.267
0.041
OP
0.281
0.031
0.369
0.004
TP
0.312
0.016
FLOW
0.639
0.001
FLOW7
0.463
0.001
0.314
0.015
0.463
0.001
0.455
0.001
____________________________________________________________________________
NCF117
VARIABLE
BOD5
BOD5LOAD
BOD20
BOD20LOAD
TURB
____________________________________________________________________________
TURB
0.388
0.002
FC
0.802
0.001
0.339
0.009
0.757
0.001
0.294
0.023
OP
0.441
0.001
0.300
0.024
0.460
0.001
0.303
0.021
TP
0.407
0.001
0.277
0.034
0.426
0.001
0.277
0.033
FLOW
0.550
0.001
0.775
0.001
0.646
0.001
0.825
0.001
0.403
0.001
0.383
0.002
0.505
0.001
FLOW7
0.393
0.002
1.000
0.0
0.480
0.001
TEMP=water temperature, TURB=turbidity, FC=fecal coliform abundance,
CHLA=chlorophyll a, FLOW=flow on day of sampling, FLOW7=average flow for seven
days preceding sampling
Table 4.5. Regression equations for prediction of BOD5 and BOD20 concentrations in
the Cape Fear, Black, and Northeast Cape Fear Rivers.
______________________________________________________________________
Cape Fear River at NC11
BOD5 = CHLA(0.065) + TURB(0.005) + 0.763; r2 = 0.38, p = 0.0001
BOD5 = CHLA(0.064) + FC(0.0008) + 0.860; r2 = 0.36, p = 0.0001
BOD20 = CHLA(0.123) + TURB(0.010) + 2.500, r2 = 0.19, p = 0.003
BOD20 = CHLA(0.123) + FC(0.0018) + 2.672; r2 = 0.19, p = 0.002
Black River at B210
BOD5 = TP(0.003) + FC(0.004) + 0.542; r2 = 0.18, p = 0.004
BOD20 = TP(0.0085) + FLOW(0.0003) + 1.673; r2 = 0.25, p + 0.0004
Northeast Cape Fear River at NCF117
BOD5 = FC(0.002) + TP(0.002) + 0.627; r2 = 0.67, p = 0.0001
BOD5 = FC(0.002) + FLOW(0.0001) + 0.781; r2 = 0.67, p = 0.0001
BOD20 = FC(0.0035) + FLOW(0.0004) + 2.313; r2 = 0.66, p = 0.0001
BOD20 = FC(0.0043) + TP(0.0067) + 1.996; r2 = 0.61, p = 0.0001
______________________________________________________________________
Table 4.6. Regression equations for prediction of BOD5 and BOD20 load in the Cape
Fear, Black, and Northeast Cape Fear Rivers.
______________________________________________________________________
Cape Fear River at NC11
BOD5 LOAD = FLOW(5.200) + + 6027.45; r2 = 0.69, p = 0.0001
BOD5 LOAD = FLOW(4.179) + TURB(247.634) + 4421.11; r2 = 0.71, p = 0.0001
BOD20 LOAD = FLOW(15.762) + 10646; r2 = 0.79, p = 0.0001
Black River at B210
BOD5 LOAD = FLOW(4.257) + 11018.40; r2 = 0.40, p = 0.0001
BOD20 LOAD = FLOW(12.994) + 2232.987; r2 = 0.40, p + 0.0001
Northeast Cape Fear River at NCF117
BOD5 LOAD = FLOW(7.532) - 324.27; r2 = 0.60, p = 0.0001
BOD20 LOAD = FLOW(19.676) + 341.60; r2 = 0.68, p = 0.0001
BOD20 LOAD = FLOW(21.84) - FC(18.26) - 84.51; r2 = 0.70, p = 0.0001
______________________________________________________________________
FIG. 4.1A. BOD5 LOAD TO LOWER
CAPE FEAR SYSTEM FROM THREE
MAJOR TRIBUTARIES
Fig. 4.2A. Lower Cape Fear River BOD5 load
(lbs BOD5/day) from the three major
tributaries, July 1998 - June 2003
NC11
NC11
B210
B210
NCF117
NCF117
FIG. 4.1B. BOD5 LOAD TO LOWER
CAPE FEAR SYSTEM INCLUDING IP
AND LIVINGSTON CREEK INPUTS
Fig. 4.2B. Lower Cape Fear River BOD5 load
(lbs BOD5/day) from the three major
tributaries, including inputs from IP and
Livingston Creek, July 1998 - June 2003
AC
AC
B210
B210
NCF117
NCF117
5.0 Fisheries Studies in the Lower Cape Fear River System,
June 2002 - June 2003
Michael S. Williams and Thomas E. Lankford
Center for Marine Science
University of North Carolina at Wilmington
5.1 Introduction
The sampling period June 2002-June 2003 represented the sixth consecutive
year of a comprehensive survey of fish populations in the lower portion of the
Cape Fear River basin. This project represents one component of the University
of North Carolina at Wilmington’s Lower Cape Fear River Program. The fisheries
component has focused on obtaining baseline data on fish community structure,
seasonal and spatial trends in abundance, disease incidence, and non-native fish
populations. This monitoring program has also provided valuable data on the
response of fish populations to hurricanes. Immediately prior to the first year of
sampling, Hurricanes Bertha and Fran made landfall over the Cape Fear River
basin. We were able to document impacts to, and short-term recovery of, the
fish community following these events in the spring and summer of 1997 (Mallin
et al. 1997; 1998). The landfall of Hurricanes Bonnie in August 1998 and Floyd
in September 1999 provided additional opportunities to examine the immediate
effects of these large-scale disturbances on fish community structure, this time
with the benefit of baseline data collected before the storms. The lack of
hurricanes during the 2000, 2001, and 2002 sampling periods gave us the
opportunity to begin documenting the long-term effects and potential recoveries
of fish communities after these large-scale disturbances. Throughout the
2001/2002 year of sampling, the Cape Fear River basin experienced a prolonged
and severe drought. This event has provided the opportunity to investigate
potential impacts of drought conditions on the fish community in the lower Cape
Fear River system. Large rain events in the spring of 2003 resulted in a recovery
from the drought and gave us the opportunity to document drought recovery
changes in the fish community (Figure 5-56). The specific objectives of this year's
study were to document seasonal and spatial patterns in 1) fish species
composition, 2) fish abundance, 3) fish disease incidence, and 4) non-native fish
populations. Our objectives also included studying the long-term effects of prior
hurricanes on fishes of both the Cape Fear and Northeast Cape Fear Rivers. We
will also be documenting changes in fish community structure within our sampling
area due to the drought of 2002 and the recovery from the drought in 2003. We
used three gear types, gillnets, trawls, and a boat electroshocker, to sample a
broad segment of the fish population. The fisheries monitoring component
remains a cooperative effort between the Lower Cape Fear River Program (Dr.
Thomas Lankford and Michael Williams, gillnets and electroshocking), and the
North Carolina Division of Marine Fisheries (NCDMF, Wilmington office, trawl).
5.2 Methods
Study Sites
Fish monitoring was conducted at each of nine fixed sites in tidal regions of the
lower watershed (Figure 5-57). Five sites were selected in the Cape Fear River
mainstem: approximately 1.5 km above the NC11 bridge (NC11 = H11), the
lower limb of the oxbow downstream from Sykes landing near Acme (AC = WL),
the mouth of the Black River below Lyon Thoroughfare (BBT = BLK), and the
mouth of Indian Creek (IC). One site was selected in the Brunswick River
between the Belleville boat ramp and the Highway 74/76 bridge (BRR). The
remaining locations were in the Northeast Cape Fear River: approximately 2 km
downstream of the NC117 bridge at Castle Hayne (NCF117 = 117), opposite the
Hoechst Celanese dock (NCF6 = GE), at the mouth of Smith Creek (Smith =
SMT), and in Horseshoe Bend (HB). Each site was located near a water quality
monitoring station.
Gillnets
Gillnets were used to sample large resident and anadromous species that are
less susceptible to electroshock and trawl collection. Sinking, 50-meter, 5 ½ inch
stretch, monofilament nets were deployed perpendicular to the current to sample
the lower half of the water column on the shoreline. At the Horseshoe Bend and
Smith Creek sites, 30-meter nets were used due to the channel being too narrow
at these locations is too narrow to set longer nets. In each sampling month the
nets were set over a three-day period. This resulted in two 24-hour soak times at
each station, and allowed sampling both during the day and night. After the first
24-hour soak period, the nets were checked and redeployed to reduce fish
mortality. Due to the high incidence of fish mortality in summer, soak times were
reduced to less than four hours during months that water temperatures exceeded
21oC. Catches were standardized to reflect a 24-hour set in our catch-per-uniteffort calculations to compensate for the reduced soak time. All fish captured
were identified, measured (nearest mm total length) and examined for external
evidence of disease (i.e. ulcerations, lesions, fin rot, structural deformities, etc.).
All fish were released at the sampling site. The number of species collected,
catch per unit effort (CPUE = number fish caught /24 hour/50 meter net), %
diseased fish (number of diseased fish divided by the total catch), and % nonnative fish (number of non-native fish divided by the total catch) was determined
for each site during each sampling month.
Trawl
North Carolina Division of Marine Fisheries (NCDMF) personnel conducted
monthly trawl sampling at each station following primary nursery trawl sampling
protocol. This sampling method targets small, bottom-oriented fishes that are
generally not collected with either of the other sampling methods. For each
sample, a 3.2 meter flat otter trawl with 0.64 cm mesh in the body, a 0.32 cm
mesh bag, and a tickler chain was towed with the current for one minute. All fish
were identified, measured (nearest mm total length, TL), examined for external
evidence of disease, and released at the study site. The number of species
collected, catch per unit effort (CPUE = number of fish / tow), % diseased fish
(number diseased fish / total catch), and % non-native fish (number of non-native
fish divided by the total catch) were determined for each site and sampling
month.
Boat electroshocker
We conducted boat-electroshocking surveys monthly at 8 of the 9 sampling
locations (water conductivity at the Brunswick River site is typically too high to
permit electroshocking). This technique targets shoreline oriented species that
are difficult to capture with trawls or gillnets. We used a 7500-watt electrofishing
system with an 18-dropper array from an aluminum boat. At each site, a 183meter reach was sampled by making a pass along each shoreline, standardizing
to a power output of 5000 watts. All stunned fish were captured using a dip net
and placed in an aerated holding tank until one side of the reach had been
sampled. Fish were then released down current of the sampling area and the
remaining side not shocked was then sampled. Fish were identified, measured
(nearest mm total length, TL), examined for external evidence of disease (e.g.,
ulcers, lesions, fin rot, structural deformities, etc.) and released at the sampling
site. The number of species collected, catch-per-unit-effort (CPUE = number of
fish / 183 m reach), % diseased fish (number of diseased fish divided by total
catch), and % non-native fish (number of non-native fish divided by the total
catch) was determined for each site and sampling month.
A mechanical failure of the electroshocking boat generator in mid-October
of 2001 prevented electrofishing and necessitated the purchase and assembly of
a new boat and generator. Consequently, the months of October 2001 to July
2002 were not sampled with this gear. A new electroshocking boat and
generator were obtained and electrofishing was resumed in July 2002.
5.3 Results and Discussion
Community-Level
Species Richness
Species richness is an important indicator of aquatic ecosystem health.
The presence of many different species in a system generally indicates a healthy
fish community with high productivity and resource availability. Declines in
species richness may signal declines in ecosystem health due to the
deterioration of water quality or biotic interactions such as predation, competition
or disease. Because 1997 was a non-hurricane year, we were able to collect all
twelve months of sampling data. In this year a seasonal pattern in species
richness and abundance was documented (Mallin et al 1999). In general species
richness tends to be higher in summer and fall than in spring and winter in the
electroshocking surveys. Although this trend has been apparent every year
since 1997, there has been a long-term decline in species richness in the
samples obtained using this gear. The trend line shows the gradual decline of
over 23% (Figure 5-44). Lack of funding caused a loss of data January through
July 2000 and October through June of 2001. Both data gaps happened during
the winter/spring seasons, which typically have lower species abundance.
Therefore, this trend toward a decline becomes a cause for concern considering
the trend line would show an even further decline if the lost data from the months
not sampled had been incorporated into the analysis.
Species richness in the trawling samples has remained fairly constant
since 1997. The trend line shows a slight increase. Species richness tends to
be lower during the spring/summer months in the trawling survey just as it is in
the electroshocking survey. The data gap from January to July in 2000 would
likely have lowered the end of the trend line and show less of an increase. It is
noteworthy that the drought between May and August of 2002 also showed the
highest number of species captured in the trawling survey since 1997. Only five
of the sixty-four months of sampling before the drought captured 18 or more
species. June, July, and August of the 2002 drought documented a catch of 19,
20, and 21 species respectively (Figure 5-45). During a drought, low freshwater
river flow allows the salt wedge to move further upstream into normally
freshwater habitat. This creates a more estuarine habitat in our sampling area,
allowing more estuarine oriented species to utilize the area. It should be
emphasized again that the lower Cape Fear River system is an important habitat
for marine fishes, and particularly juvenile marine fishes. The functional value of
Cape Fear River nursery habitat depends largely on its ability to provide biotic
and abiotic conditions that are suitable for growth and survival of juvenile fishes.
Because many resource species utilize the Cape Fear River system as a juvenile
nursery, it is important that environmental conditions be monitored closely and
that these habitats receive protection from anthropogenic or other impacts that
compromise their suitability as habitat.
Gillnetting species richness has been highly variable. Catches are still
dominated by non-natives. A difference in richness was documented between
the low flow winter/spring season of 2001 and the high flow winter/spring season
of 2002. This is contrary to species richness decreases documented after high
flow events in the spring flood of 1998 and the hurricane flood of 1999 (Figure 546). Future surveys should focus on what influences species richness during
flood and non-flood events.
Abundance
Catch-per-unit-effort in electroshocking samples went up sharply in the
2001 samples. Other than this increase, electroshocking CPUE has declined
every year since 1997 (Figure 5-47). No seasonal trends have been
documented.
The trawling CPUE trend line shows an increase. This increase was
driven by unprecedented catches of Atlantic croaker, spot, southern flounder and
hogchokers during the springs of 2001 and 2002. The 2003 spring trawling
CPUE is well above the 1997-1999 spring seasons but over 50% less than the
2001 spring season (5-48). Observation of flow rates during this time of year do
not suggest a correlation between flow rate and the above average trawling
catches (Figure 5-56).
Gillnetting catch-per-unit-effort trends remain relatively constant since
1997 (Figure 5-49). The trend line shows an increase due to the exceptionally
large catches of blue catfish during June and July of 2002. An effort of only 1.5
net days in June captured 31 blue catfish along with 7 other fish, and in July 2.1
net days netted 24 blue catfish and 18 other fish. It appears the drought of 2002
increased blue catfish catch-per-unit-effort. It will be important in future surveys
to investigate whether the drought caused the increase in CPUE or if there were
actually more blue catfish in our sampling area. Catch-per-unit-effort is used to
indicate a population size. If environmental conditions are affecting non-native
fishes susceptibility to gillnets, however, then the data may show a change in
population size when environmental conditions actually caused the change.
Whether the low flows caused the catfish to become more susceptible to gillnets
or more catfish were in the area, future surveys should investigate how droughts
affect the catch of blue catfish in the Cape Fear River.
Disease
Whether from exposure to toxicants, environmental stressors, or resource
limitation, high infection rates in a fish community indicate a deterioration of
ecosystem health and function. Fishes captured in this survey that exhibit
external signs of disease are closely examined. The capture site, the anatomical
sites of diseases, and a description of the diseases are documented for each
specimen. Disease percentages in the electroshocking samples have been
highly variable since 1997. No seasonal or spatial patterns have been observed.
Although there are data gaps for the periods January-July 2000 and NovemberJune 2002, the long-term data suggest a decline in overall disease incidence
(Figure 5-50). In fact, the July 2002-June 2003 season had the lowest disease
incidence of any season other then the July-June 2000 season (for which six
months of data were missing. For the current year, species with the highest
disease percentage were bowfin (34%), striped bass (25%) and largemouth bass
(10.6%).
The trawling survey typically captures small, young fishes which are
difficult to observe for the small lesions and/or ulcerations that we use to
document external signs of disease in this program. This is likely the reason that
of the >50,000 fishes captured in the trawling survey, only two fish have been
documented to have external signs of disease (Figure 5-51). For this reason, the
trawling data are not considered to be a good indicator of disease percentages.
The gillnet data showed a decline in disease percentage. The trend line
showed over a 50% drop from January of1997 to June of 2003 (Figure 5-52).
The decline in the percentage of diseased Bowfin was a major contributor to the
drop in the overall disease percentage. Of the 18 bowfin captured in the gillnets
during the period June 2002-June 2003, none showed external signs of disease.
The two species captured in gillnets with external signs of disease were striped
bass (7.8 %) and blue catfish (1.9%).
Non-natives
Trend lines for percent non-native species captured in the electroshocking
survey increased slightly since 1997. Higher than average catches in the fall of
2000, spring of 2001, and spring of 2003 caused the increase in the trend line
(Figure 5-53). Large catches of redear sunfish, common carp and blue catfish
led to the sharp increase of percent non-native during the 2002/2003 season.
Trawling trends show little change in non-native percentages. Large
catches of blue and channel catfish in the winter of 1997 and spring of 1998 have
skewed the trend line to show a decreasing non-native percentage in the most
recent years of sampling (Figure 5-54). The non-native catches are driven by
blue catfish, channel catfish, and redear sunfish.
Although the gillnetting catch percentage continues to vary widely (0100%) there is a slight trend toward an increasing non-native percentage (Figure
5-55). Catches continue to be dominated by blue catfish, flathead catfish, and
common carp. When all the samples are combined from January 1997 to June
2003, the non-native percentage of resident fish is just over 56%. Blue catfish
continue to dominate the gillnet catch (64%) as-well-as the non-native gillnet
catch (37%).
Non-natives are species that have been introduced, either intentionally or
by accident, to systems and do not naturally occur there. Non-natives often prey
on and compete with native species for resources. They are often tolerant of a
wide range of environmental conditions and may have fewer natural predators
than native species. This gives non-natives a competitive advantage that can
lead to the population suppression or extirpation of more desirable native
species. Dr. Mary Moser, for example, documented the extirpation of native
catfish from the Cape Fear River system by the non-native blue (Ictalurus
furcatus), flathead (Pylodictis olivaris), and channel (Ictalurus punctatus)
catfishes (Moser and Roberts 1999). The lower Cape Fear River Program has
captured just 3 native catfish since 1997 compared to >2,000 non-native
catfishes. Flathead catfish are piscivorous at age 1 and are known to consume
largemouth bass, catfish and sunfishes (Ashley and Buff 1987, Hackney, P. A.
1965). The state record blue catfish is 80 pounds, the state record flathead
catfish is 69 pounds and the state record channel catfish is 40 pounds. In
contrast the largest of the native catfish species reaches just 13 pounds. The
large body sizes and high abundance of these non-native catfishes are likely
having dramatic impacts on the native fish community.
Grass carp (Ctenopharyngodon idella) are another non-native species of
concern. Grass carp have reached sizes of over 60 pounds in this state. They
are herbivores and have been introduced to reservoirs and ponds throughout the
Cape Fear River basin to control aquatic vegetation. When they are introduced
to the Cape Fear by flooding events, however, they consume aquatic vegetation
that functions in controlling erosion and as nursery habitat for juvenile fishes.
The state of North Carolina recognized the potentially destructive habits of this
species and requires that all grass carp be certified as triploid before they can be
introduced to ponds and reservoirs. A study in the Chesapeake Bay found that
although stocking of non-sterile grass carp has been illegal since 1979, 18% of
the feral grass carp collected in Chesapeake Bay tributaries were not triploid.
The researchers speculated that the non-triploid carp originated from illegal
stocking efforts or had been introduced them before the regulations were put into
place (Schultz et. al. 2001). If a mistake has been made and 100% of the grass
carp introduced were not sterile, then there could be a reproducing population of
grass carp in the Cape Fear. If conditions are favorable, it takes only a few
individuals to populate a river system. An example would be the flathead catfish.
Eleven individuals were introduced in 1966 and they are now one of the
dominant predators in the Cape Fear River system. A reproducing population of
non-native grass carp could thus severely impact our fisheries resources
(Raibley et al. 1995). Catch data provided from this program continues to
document low numbers of grass carp in the Lower Cape Fear River. It is also
noteworthy that all individuals captured have been between 633 mm (24 inches)
and 1097 mm (43 inches). Captures of smaller sizes of grass carp (ie. <150mm /
6 inches) may indicate reproduction within the river system. Due to the
observations of low catch numbers (six between June 2002 and June 2003) and
size classes larger than that expected from the young-of-the-year size class,
there is no data to document grass carp reproduction in the lower Cape Fear
River. Future surveys should continue to document the sizes and numbers of
grass carp captured so that if reproduction becomes likely, then appropriate
management plans can be initiated.
Trends in Abundance of Important Species
American Shad
Throughout the history of settlement on the Cape Fear River, the spring
spawning run of the American shad (Alosa sapidissima) has supported a very
important commercial and recreational fishery. Commercial landings of this
species have shown a gradual decline since the early 1970's, indicating a
decrease in their population size. To stem any further decline in their numbers,
the North Carolina Division of Marine Fisheries enacted a Fisheries Management
Plan for the American shad. In 1998 an amendment to the Interstate
Management Plan for American Shad included a phase out of the offshore shad
fishery over a five-year period beginning in 1999. American shad migrate from
Canada to Florida. The offshore fishery intercepts shad that are migrating south
to spawn in the rivers and streams they originated from. If North Carolina shad
are being captured in Massachusetts, resource managers here cannot regulate
the shad fishery properly. With the offshore phase out, the Cape Fear River
shad fishery will become even more important. Catch-Per-Unit-Effort data have
shown large fluctuations over the six seasons of sampling, but no distinct trends
have been observed. This spring’s flow rates were the second highest recorded
since 1997 and had the third largest catch-per-unit-effort of American shad. Last
spring, however, had the lowest flow observed during this survey and the highest
April CPUE of the survey. Thus, our data do not indicate a strong relationship
between river flow during spring months and the abundance of adult American
Shad (Figure 5-20).
Atlantic Sturgeon
Historically, North Carolina supported a large sturgeon fishery. Due to
overfishing, habitat degradation, and dam construction, the Atlantic sturgeon
(Acipenser oxyrhynchus) is currently classified as a threatened species in North
Carolina and their possession has been banned since 1991. The shortnose
sturgeon (Acipenser brevirostrum) also occurs in this drainage (Moser and Ross
1995) and has undergone such a dramatic population decline that it has been
federally listed as a endangered species. Both species of sturgeon can live over
60 years. While the shortnose reaches it's maximum size at around 100 cm
(3.33 feet) the Atlantic sturgeon can attain sizes exceeding 300 cm (9.8 feet) and
270 kg (>600 pounds). Sturgeon are harvested for the meat, insinglass made
from the swim bladders, emulsifiers and thickeners from the cartilagenous
backbone, leather products made from their thick skin, and most importantly, the
roe, which can be made into high quality caviar (Williams and Moser 1999). With
American sturgeon caviar currently selling for $192.00 a pound and smoked
sturgeon selling for $14.00 a pound, overfishing can quickly become a problem.
Recent catches of ripe sturgeon during the spring spawning season and the
regular catches of juveniles in this survey indicate a reproducing population in
this drainage. Although previous years have documented relatively similar catchper-unit-efforts, the summer of 2002 yielded twice the CPUE of any season since
1997. This also happens to be the lowest flow conditions experienced during this
survey. Although catch-per-unit-effort increased greatly during these low flows
conditions, previous years with low flow summers did not have the same
resulting increases in CPUE. Future surveys should investigate river flow and
other environmental conditions that may impact the Atlantic sturgeon’s use of the
Lower Cape Fear River (Figure 5-21).
Blue Catfish
The blue catfish (Ictalurus furcatus) was introduced to the Cape Fear River by
the Wildlife Resources Commission in the attempt to create a trophy fishery
(Moser and Roberts 1998). Although blue catfish were uncommon in the 1970's,
they are currently the most abundant species captured in our gillnet survey
(Mallin et. al. 1998,1999,2000,2001,2002). The success of the blue catfish in the
Cape Fear River system is likely due to its generalist feeding behavior. Gut
content analyses have shown this species to feed on a wide range of prey
including snakes, birds, fish, shrimp, worms, eels, grapes, other fish, and
suprisingly clams. Over 75% of the stomachs examined contained an Asian
fresh water clam (Corbicula fluminia) that was introduced by a bilge discharge in
the Wilmington harbor in 1975 (Williams and Moser, in prep). Although thought
to have aided in the demise of our native catfish population through competition,
blue catfish are a popular sport fish and support a small commercial fishery in the
Cape Fear River. Blue Catfish CPUE in the trawling survey continue to be highly
variable, but maintain a trend that doesn’t increase or decrease to any
appreciable degree. Blue catfish gillnetting CPUE, however, increased last
summer during the drought to over four times higher than previously documented
by this survey. This species continues to be the dominant catch in the gillnet
survey, comprising thirty-seven percent of the total catch and sixty-four percent
of the non-native catch. Catch-Per-Unit-Effort shows a slight increase in the
trawling trend lines. This is due to an extremely large catch of blue catfish in
March of 2003 (Figure 5-24). It is interesting to note that there was a large catch
of adults during June and July of 2002 and a large catch of juveniles in March
and April of 2003. Future surveys should investigate if large summer catches of
adults can lead to increases in juvenile abundance the following spring.
Bowfin
Although much maligned by many fisherman, bowfin (Amia calva) are an
important predator in the Cape Fear River system (Mallin et. al.
1998,1999,2000). This native species not only assists in keeping the forage
base balanced, it can be used as a valuable indicator of the quality of water that
it inhabits. This species can use a modified swim bladder to absorb oxygen from
the air (Guier, et al 1994). This permits bowfin to utilize hypoxic areas in the
water where other predators are excluded. Although disease incidence is still
high (>25%), this seasons sample showed one of the lowest disease
percentages documented by the survey. A high incidence of diseased bowfin
may indicate poor water quality. The most common external sign of disease was
termed scale hemorrhage. The term was used to describe areas on the fish
where multiple scales were missing and the underlying skin appeared red or
inflamed. Investigations into the cause of these infections may shed light on
potential bioaccumulation of toxins by this species or attacks by toxic alga in the
Cape Fear River system. Catch-per-unit-effort increased slightly in the gillnetting
samples but dropped impressively in the electroshocking samples since 1997.
Throughout this survey, bowfin exhibited the highest infection rate of any species
captured. Drops in abundance coupled with drops in disease percentages may
indicate a problem. It may be that exposure to toxicants, environmental
stressors, resource limitation, or unknown sources for their high infection rates
are reaching critical levels and the infected individuals are being eliminated from
the population. Future surveys should focus on the decreases in CPUE of bowfin
(Figure 5-26).
Channel catfish
Channel catfish were introduced into the Cape Fear in the early 1900's (Smith
1907). A small but stable population was established that persisted through the
1970's. In recent years, however, this species has shown "reductions in relative
abundance since the introduction of the blue and flathead catfishes."(Moser and
Roberts 1998). The decline is likely due to competition with blue catfish. This
survey shows no significant trends in catch-per-unit-effort but did have the
highest gillnetting CPUE of the survey in July of 2002 and a trawling catch that
was four times higher than any channel catfish CPUE since 1997. As with the
blue catfish, there was a large catch of adults in the summer of 2002 and a large
catch of juveniles in the winter/spring of 2003. Future surveys should investigate
if large summer catches of adults can lead to increases in juvenile abundance
the following spring. (Figure 5-28).
Atlantic croaker and spot
In 2000 there were over 2.8 million pounds of spot (Leiostomus xanthurus) and
over 10 million pounds of Atlantic croaker (Micropogias undulatus) sold in North
Carolina. As with many marine species, croaker and spot spawn offshore and
their larvae migrate into estuarine nursery habitat (Norcross 1991). The Cape
Fear River system is used as nursery habitat by these species (Mallin et. al.
1998,1999,2000,2001). Catch-per-unit-effort can exceed hundreds per trip.
Atlantic croaker populations can fluctuate widely, and have shown this pattern in
the Cape Fear. In 1998 croaker had a statistically significant higher catch-perunit-effort in our fall samples, but no other changes have been documented
(Figure 29). Spot showed no major fluctuations in abundance until the spring of
2001 when catch-per-unit-effort was 10 times higher than previously documented
by this survey. The spring of 2002 showed a seventeen-percent larger CPUE
than the 2001 catch. Both of these species are important to recreational and
commercial fisheries here in North Carolina. It is important that water quality and
aquatic vegetation be protected in the Cape Fear. This way the critical nursery
habitat is available and important commercial fisheries are not negatively
affected (Figure 5-38).
Flathead catfish
In 1966 the North Carolina Wildlife Resources Commission introduced the
flathead catfish (Pylodictis olivaris) to the Cape Fear River in an attempt to create
a trophy fishery (Moser and Roberts 1998). Within 15 years of their introduction,
the flathead catfish was found to be the most abundant catfish by weight and
considered to be the new dominant predator in the Cape Fear (Guier et. al.
1981). Guier's study in the late 1970's showed that fish (99.4% by weight ) were
the principle prey of P. olivaris. Catfishes were the dominant fish found in the
flathead's diet (Guier et al. 1981, Ashley et al. 1989). This is a strong indication
that the introduction of this species has led to the severe decline of our native
catfish populations. The lower Cape Fear River Program has captured 3 native
catfish since 1997 compared to over two-thousand non-native catfishes. Thus
less than 0.1% of our catfish captures are native species. Future studies should
reexamine the diet of flatheads to determine which prey species are currently
being exploited as a food source. When all samples from this program are
combined there is a slight trend toward an increasing CPUE but no significant
patterns have been observed. (Figure 5-30).
Hybrid-striped bass
Hybrid striped bass are a hybrid of striped bass (Morone saxatalis) and white
bass (Morone chrysops). They have been stocked as a put and take fishery in
Lake Jordon nearly every year since 1983. The hybrids are introduced to the
Cape Fear River by flooding events. Through competition, hybrids utilize the
resources normally available to striped bass (Patrick and Moser 2001). Hybrids
do not reproduce and so the resources they keep from striped are not converted
into reproduction. As a result of competition with hybrids, striped bass may not
be as healthy and in turn, not produce as many juveniles. Tag and recapture
data from studies conducted in this drainage suggested that hybrids conduct a
spawning run with true striped bass as has been documented in other systems
(Patrick and Moser 2001). Due to competition with true striped bass for food
resources and spawning habitat, hybrid striped bass are likely having a negative
impact on the striped bass population in the Cape Fear River system. While
commercial landings of striped bass in North Carolina have shown a gradual
increase since 1990, landings in the Cape Fear System remain low and this is
the only river in North Carolina that stocks hybrid striped bass. Although the
hybrid striped bass population appeared to have decreased since 1997, we have
had an increase in the fall of 2002. (Figure 5-34). Due to gradual decreases in
CPUE during non-hurricane years, it was suggested in last years report that
individuals were likely introduced to the lower Cape Fear River system by
flooding events upstream. The increase in the fall CPUE of 2002 however,
followed a severe drought during the summer of 2002. Future surveys should
focus on the conditions that impact the population size of hybrid striped bass in
the Lower Cape Fear River system.
Longnose gar
Longnose gar (Lepisosteus osseus) are freshwater piscivores that can reach six
feet in length and weigh over fifty pounds. These predators not only consume
game fishes but also compete with more desirable species such as striped and
largemouth bass. This makes these non-game fish unpopular with local
fisherman. This species can tolerate a wide range of environmental conditions.
Although the gar captured in this survey showed a high occurrence of wounds,
probably from motorboat propellers, no fish exhibited external signs of disease.
Knowing their relative population levels allows us to track their potential impact
on other fish populations. There has been a trend toward lower a lower catchper-unit-effort but no patterns have been documented in the electroshocking or
gillnet surveys (Figure 5-36).
Southern flounder
The flounder fishery is the most lucrative finfish fishery in North Carolina. In
2000 this fishery was valued at over 11.6 million dollars. The vast majority of
flounder caught in North Carolina are summer flounder (Paralichthys dentatus)
and the southern flounder (Paralichthys lethostigma). While the summer flounder
tend to inhabit more saline waters, southern flounder are found throughout our
more freshwater survey area. Large catches (>100) of juveniles in the spring
indicate that the Cape Fear River system is an important nursery for P.
lethostigma. Although coast wide landings of southern flounder are declining, we
observed a statistically significant increase in the spring 2001 trawling and
shocking catch-per-unit-effort. The 2002 spring trawling catch-per-unit-effort was
significantly lower than that of 2001, but was still twice as high as any of the other
years (Figure 5-42). The spring season of 2002 showed an increase in CPUE
from last year and documented the second largest CPUE since 1997. It is hoped
that the large catch-per-unit-efforts of last the two years is an indication of large
year-classes that will soon enter the adult population.
Striped bass
Striped bass (Morone saxitilis) are one of 7 anadromous species found in the
Cape Fear River system. Due to dramatic drops in the population, a coast wide
moratorium on striped bass fishing was imposed from 1985 to 1990. Although
striped bass populations in other N. C. drainages have rebounded, the Cape
Fear River striped bass population has not (Mallin et. al.
1998,1999,2000,2001,2002). Declines in water quality and the introduction and
possible predation by non-native catfishes are probably contributing to the
problem, one specific culprit could be competition from hybrid striped bass.
Gillnet surveys showed the average catch-per-unit effort of striped bass from
1990 to 1992 declined by 50% when compared to the catch-per-unit average
from 1996 to 1999. Unfortunately, the same survey showed a more than doubling
of the catch-per-unit-effort of hybrid striped bass during the same time period
(Patrick and Moser 2000). Tag and recapture data and the capture of spent
hybrid females also indicate that the hybrid striped bass conduct a spawning run
with the striped bass and may be competing for mates and spawning habitat.
The true striped bass and the hybrids have a very high diet overlap. If food
resources, spawning habitat, or spawning partners are limited, it is likely that the
hybrids are depressing the true striped bass population in the Cape Fear. CatchPer-Unit-Effort was the higher during the 2002/2003 season than any other
season documented since 1997. This increase comes after a major drought it is
interesting, although low flow conditions in previous years did not have the same
resulting increases in CPUE. Future surveys should investigate river flow and
other environmental conditions that may impact the spring anadromous run of
striped bass in the Lower Cape Fear River. (Figure 5-40).
5.4 Summary and Recommendations
The reintroduction of electroshocking data from this years survey has given us
the ability to closely monitor species richness and disease incidence. Species
richness in samples provided by this gear has shown declines that give cause for
concern. Trend line analysis shows over a 23% drop and this is excluding a
seven-month and a nine-month data gap that would likely have lowered the trend
line further due to the time of year in which they occurred. Although the drought
had little, if any effect on overall fish community structure, non-native
percentages, or disease incidence, species richness reached record levels in the
trawling surveys. This suggests the drought created a more estuarine
environment in our sampling area and more estuarine dependant species were
therefore captured. The catches of estuarine dependent species further
reinforces the important role the Cape Fear River system plays as habitat for not
only resident species but estuarine and marine species. Drops in disease
percentages in the electroshocking and gillnets surveys were mostly driven by
the drops in the disease percentage of bowfin. Although most of the trend
analysis showed no discernable patterns in a positive or negative direction, a
trend toward decreasing species richness and catch-per-unit-effort in the
electroshocking surveys may be developing and should be closely monitored in
future surveys.
At the species-level,
It is recommended that future monitoring efforts be expanded to address
several important issues concerning Cape Fear River fish communities.
1)
Diets of non-native catfishes (particularly blue catfish and
flathead catfish) should be reexamined to determine whether
these introduced predators continue to exploit native catfishes as
prey. With such substantial drops in the native catfish
population, it will be important to assess their potential predatory
impacts on other native species due to the depletion of one of
their prey items.
2)
Ploidy testing of feral grass carp should also be considered to
assess their potential for reproduction and whether adults
currently in the system are likely to establish a breeding
population.
3)
Toxicant/contaminant testing should be incorporated as a
parameter for routine monitoring.
4)
Tagging of resource and indicator species should be conducted
during routine sampling. This would enable mark/recapture
studies to estimate important biological parameters, including
population size, growth rate, home range, and migratory
patterns.
5)
Finally, it is critical that future monitoring efforts continue without
interruption such that additional data gaps do not further impede
the survey’s ability to document seasonal, spatial, and
interannual trends, as well as patterns of response to, and
recovery from, ecosystem disturbance.
5.5 Acknowledgements
We thank the Division of Marine Fisheries, Wilmington office for conducting the
trawling portion of this survey, and for continued technical and logistical support.
Field assistance was provided by, Melissa Anderson, Donald Burkhalter, Steve
Hall, Susanna Holst, Roger Keeter, Matthew McIver, Bethany Noller, Robert
Mires, Wiley Rimmer, Andrea Quattrini, Doug Parsons, Anthony Santoes, Joshua
Slater, and Darrell Watson.
5.6 Literature Cited
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Fear River, North Carolina. Proceedings of the Annual Conference of the
Southeast Association of Fish and Wildlife Agencies, 41:93-99.
Guier C. R., L. E. Nichols, and R. T. Rachels. 1981. Biological investigation of
flathead catfish in the Cape Fear River. Proceedings of the Annual Conference
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Hendrick, M. S., S. L. Katz, D. R. Jones. 1994. Periodic air-breathing in a
primitive fish revealed by spectral analysis. Journal of Experimental Biology
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Hackney, P. A. 1965. Predator-prey relationships of the flathead catfish in ponds
under selected forage fish conditions. Proc. Ann. Conf. S.E. Assoc. Game and
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H. Ensign, and J. F. Merritt. 1997. Environmental Assessment of the Lower
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Alphin, M. S. Williams, M. L. Moser, and J. F. Merritt. 2001. Environmental
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Wilmington, Wilmington, N.C.
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Alphin, M. S. Williams, and J. F. Merritt. 2002. Environmental Assessment of the
Lower Cape Fear River System, 2001-2002. CMSR Report No. 02-01. Center
for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Moser, M.L., and S.B. Roberts. 1999. Effects of non-indigenous ictalurid
introductions and recreational electrofishing on native ictalurids of the Cape Fear
River drainage, North Carolina. Pages 479 – 486 in E. R. Irwin, W. A. Hubert, C.
F. Rabeni, H. L. Schramm, Jr., and T. Coon, editors. Catfish 2000: proceedings
of the international ictalurid symposium, American Fisheries Society, Symposium
24, Bethesda, Maryland.
Moser and Ross. 1995. Habitat use and movements of shortnose and Atlantic
sturgeons in the Cape Fear River, North Carolina. Transactions of the American
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List of Figures
Figure 5-1. Fish Collections: Cape Fear River at H11 (NC11), 2003
Figure 5-2. Fish Collections: Cape Fear River at Syke's Landing, 2003
Figure 5-3. Fish Collections: Cape Fear River at Black River, 2003
Figure 5-4. Fish Collections: Cape Fear River at Indian Creek, 2003
Figure 5-5. Fish Collections: Cape Fear River at Brunswick River, 2003
Figure 5-6. Fish Collections: Northeast Cape Fear River at Castle Hayne
(NCF117), 2003
Figure 5-7. Fish Collections: Northeast Cape Fear River at GE (NCF6), 2003
Figure 5-8. Fish Collections: Northeast Cape Fear River at Smith Creek
(Smith), 2003
Figure 5-9 . Fish Collections: Cape Fear River at HorseshoeBend (HB), 2003
Figure 5-10 . Fish collections pooled by station (all months), 2003. Error bars
represent standard error.
Figure 5-11 . Fish collections pooled by month (all stations), 2003. Error bars
represent standard error.
Figure 5-12 . Number of Species at all Stations by Month, 2003. Error bars
represent standard error
Figure 5-13. Catch-Per-Unit-Effort at all Stations by Month, 2003. Error bars
represent standard error
Figure 5-14. Percent Diseased Non-transients Captured at all Stations by
Month, 2003
Figure 5-15. Percent Non-natives captured at all Stations by Month, 2003
Figure 5-16. Number of Species Captured at all Stations by Gear Type 19972003
Figure 5-17. Catch-Per-Unit-Effort of Each Gear Type by Month 1997 – 2003
Figure 5-18. Percentage of all Resident Diseased Fish by Season 1997 –
2003
Figure 5-19. Non-native Percentage of Resident Fish by Season 1997 – 2003
Figure 5-20. Catch-Per-Unit-Effort of American Shad (Alosa sapidissima)
1/1997- 5/2003
Figure 5-21. Catch-Per-Unit-Effort of American Shad (Alosa sapidissima) by
Station 1/1997- 5/2003
Figure 5-22. Catch-Per-Unit-Effort of Atlantic Sturgeon (Acipenser
oxyrhynchus) and 1/1997 - 5/2003
Figure 5-23. Catch-Per-Unit-Effort of Atlantic Sturgeon (Acipenser
oxyrhynchus) by Station 1/1997 - 5/2003
Figure 5-24. Catch-Per-Unit-Effort of Blue Catfish (Ictalurus furcatus)
1/1997 - 5/2003
Figure 5-25. Catch-Per-Unit-Effort of Blue Catfish (Ictalurus furcatus) by Station
1/1997 - 5/2003
Figure 5-26. Catch-Per-Unit Effort of Bowfin (Amia calva) 1/1997 –
5/2003
Figure 5-27. Catch-Per-Unit Effort of Bowfin (Amia calva) by Station 1/1997 –
5/2003
Figure 5-28. Catch-Per-Unit-Effort of Channel Catfish (Ictalurus
punctatus) 1/1997 - 5/2003
Figure 5-29. Catch-Per-Unit-Effort of Channel Catfish (Ictalurus
punctatus) by Station 1/1997 - 5/2003
Figure 5-30. Catch-Per-Unit-Effort of Flathead Catfish (Pylodictus
olivarius) 1/1997 - 5/2003
Figure 5-31. Catch-Per-Unit-Effort of Flathead Catfish (Pylodictus
olivarius) 1/1997 - 5/2003
Figure 5-32. Catch-Per-Unit-Effort of Grass Carp (Ctenopharyngodon idella) by
Station 1/1997 - 5/2003
Figure 5-33. Catch-Per-Unit-Effort of Grass Carp (Ctenopharyngodon idella) by
Station by Station by Station 1/1997 - 5/2003
Figure 5-34. Catch-Per-Unit-Effort of Hybrid Striped Bass (Morone saxatilis X
Morone chrysops) 1/1997 - 5/2003
Figure 5-35. Catch-Per-Unit-Effort of Hybrid Striped Bass (Morone saxatilis X
Morone chrysops) by Station 1/1997 - 5/2003
Figure 5-36. Catch-Per-Unit-Effort of Longnose Gar (Lepisosteus osseus)
1/1997 - 5/2003
Figure 5-37. Catch-Per-Unit-Effort of Longnose Gar (Lepisosteus osseus) by
Station 1/1997 - 5/2003
Figure 5-38. Catch-Per-Unit-Effort of Spot (Leiostomus xanthurus) 1/1997 5/2003
Figure 5-39. Catch-Per-Unit-Effort of Spot (Leiostomus xanthurus) by Station
1/1997 - 5/2003
Figure 5-40. Catch-Per-Unit-Effort of Striped Bass (Morone saxatilis) 1/1997 5/2003
Figure 5-41. Catch-Per-Unit-Effort of Striped Bass (Morone saxatilis) 1/1997 5/2003
Figure 5-42. Catch-Per-Unit-Effort of Southern Flounder (Paralichthys
lethostigma) 1/1997- 5/2003
Figure 5-43. Catch-Per-Unit-Effort of Southern Flounder (Paralichthys
lethostigma) 1/1997- 5/2003
Figure 5-44. Number of Species Captured in the Electroshocking survey
1/1997- 5/2003
Figure 5-45. Number of Species Captured in the Trawling survey 1/19975/2003
Figure 5-46. Number of Species Captured in the Gillnetting survey 1/19975/2003
Figure 5-47. Average Monthly Catch-Per-Unit-Effort in the Electroshocking
survey 1/1997- 5/2003
Figure 5-48. Average Monthly Catch-Per-Unit-Effort in the Trawling survey
1/1997- 5/2003
Figure 5-49. Average Monthly Catch-Per-Unit-Effort in the Gillnetting survey
1/1997- 5/2003
Figure 5-50. Average Monthly Disease Percentage of Resident Fish Captured in
the Electroshocking survey 1/1997- 5/2003
Figure 5-51. Average Monthly Disease Percentage of Resident Fish Captured in
the Trawling survey 1/1997- 5/2003
Figure 5-52. Average Monthly Disease Percentage of Diseased Resident Fish
Captured in the Gillnetting survey 1/1997- 5/2003
Figure 5-53. Average Monthly Non-native Percentage of Resident Fish
Captured in the Electroshocking survey 1/1997- 5/2003
Figure 5-54. Average Monthly Non-native Percentage of Resident Fish
Captured in the Trawling survey 1/1997- 5/2003
Figure 5-55. Average Monthly Non-native Percentage of Resident Fish
Captured in the Gillnetting survey 1/1997- 5/2003
Figure 5-56. Average Monthly Non-native Percentage of Resident Fish
Captured in the Gillnetting survey 1/1997- 5/2003
Figure 5-57. Map of sampling locations in the Lower Cape Fear River.
Figure 5-57 Map of Fisheries sampling on the Lower Cape Fear River.