Lower Cape Fear River Program 2009 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2009
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
September 2010
CMS Report No. 10-04
Center for Marine Science
University of North Carolina Wilmington
Wilmington, N.C. 28409
UNCW Estuarine Biology class 2010 Fish nursery area along Cape Fear Estuary
Persistent blue-green Microcystis algal bloom in Cape Fear River, fall 2009 Microcystis blue-green bloom magnified 150X
Executive Summary
Multiparameter water sampling for the Lower Cape Fear River Program (LCFRP) has
been ongoing since June 1995. Scientists from the University of North Carolina
Wilmington’s (UNCW) Aquatic Ecology Laboratory perform the sampling effort. The LCFRP currently encompasses 36 water sampling stations throughout the Cape Fear, Black, and Northeast Cape Fear River watersheds. The LCFRP sampling program
includes physical, chemical, and biological water quality measurements and analyses of
the benthic and epibenthic macroinvertebrate communities, and has in the past included
assessment of the fish communities. Principal conclusions of the UNCW researchers conducting these analyses are presented below, with emphasis on water quality of the period January - December 2009. The opinions expressed are those of UNCW
scientists and do not necessarily reflect viewpoints of individual contributors to the
Lower Cape Fear River Program.
The mainstem lower Cape Fear River is a 6th order stream characterized by periodically turbid water containing moderate to high levels of inorganic nutrients. It is fed by two
large 5th order blackwater rivers (the Black and Northeast Cape Fear Rivers) that have
low levels of turbidity, but highly colored water with less inorganic nutrient content than
the mainstem. While nutrients are reasonably high in the river channels, major algal blooms have until recently been rare because light is attenuated by water color or turbidity, and flushing is usually high (Ensign et al. 2004). During periods of low flow (as
in 2008) algal biomass as chlorophyll a increases in the river because lower flow causes
settling of more solids and improves light conditions for algal growth. Periodically major
algal blooms are seen in the tributary stream stations, some of which are impacted by point source discharges. Below some point sources, nutrient loading can be high and fecal coliform contamination occurs. Other stream stations drain blackwater swamps or
agricultural areas, some of which periodically show elevated pollutant loads or effects
(Mallin et al. 2001).
Average annual dissolved oxygen (DO) levels at the river channel stations for 2009 were similar to the average for 1996-2008. Dissolved oxygen levels were lowest during
the summer, often falling below the state standard of 5.0 mg/L at several river and
upper estuary stations. There is a dissolved oxygen sag in the main river channel that
begins at Station DP below a paper mill discharge and near the Black River input, and persists into the mesohaline portion of the estuary. Mean oxygen levels were highest at the upper river stations NC11 and AC and in the middle to lower estuary at stations M42
to M18. Lowest mainstem average 2009 DO levels occurred at the lower river and
upper estuary stations DP, BBT, IC, NAV, HB, BRR and M61 (6.6-6.9 mg/L). As the
water reaches the lower estuary higher algal productivity, mixing and ocean dilution help alleviate oxygen problems.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River. These rivers are classified as blackwater systems because
of their tea colored water. The Northeast Cape Fear River often seems to be more oxygen stressed than the Black River; as such, in 2009 Stations NCF117 and B210,
representing those rivers, had average DO concentrations of 6.2 and 7.2 mg/L, respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2009. Station BCRR (upper Burgaw Creek) and SR (South
River) had DO levels below 4.0 mg/L 58% of the occasions sampled, with NC403
(Northeast Cape Fear River headwaters) and GS (Goshen Swamp) 50%, and LVC2 (Livingston Creek) below standard 33% of occasions sampled. Considering all sites sampled in 2009, we rated 19% as poor for dissolved oxygen, 11% as fair, and 69% as
good.
Annual mean turbidity levels for 2009 were generally similar to the long-term average. Highest mean turbidities were at the upper estuary sites NAV (27 NTU), HB (26 NTU) and BRR (25 NTU) with turbidities gradually decreasing downstream through the
estuary. Turbidity was much lower in the blackwater tributaries (Northeast Cape Fear
River and Black River) than in the mainstem river, and were low in general in the lower
order streams. Regarding stream stations, chronic or periodic high nitrate levels were found at a
number of sites, including BC117 (Burgaw Creek below Burgaw), ROC (Rockfish
Creek), 6RC (Six Runs Creek), NC403, and PB (Panther Branch). Average chlorophyll
a concentrations were larger than usual, particularly from June through August 2009; during this same period river flow as measured by USGS at Lock and Dam #1 was lower for 2009 compared with the 1995-2009 long-term average (1,898 CFS compared
with 3,704 CFS). In the estuary blooms occurred from M61 through M35, and stream
stations that hosted algal blooms included GS, NC403, PB and SR, but this represented
fewer blooms than in 2008. The most troublesome occurrence was the presence of cyanobacteria (i.e. blue-green algal blooms) in the Cape Fear River during autumn near and upstream of NC11. These consisted of Microcystis aeruginosa, which can produce
toxins, and their persistence and concentrations was the greatest seen in this section of
the river during the length of the Lower Cape Fear River Program. We note that fish
kills did not occur related to the blooms. Several stream stations, particularly BC117, BCRR, ROC, PB, BRN (Browns Creek),
HAM, SAR (Northeast Cape Fear River near Sarecta), LVC2 and LRC showed high
fecal coliform bacteria counts on a number of occasions. Periodically biochemical
oxygen demand (BOD) concentrations in several Northeast Cape Fear River watershed stream stations (especially AC, N403, GS, ANC) and Station LVC2 in the Cape Fear Watershed were elevated (BOD5 3.0 mg/L or greater). Collection of water column
metals was suspended in early 2007 as they are no longer required by NC DWQ.
This report also includes an in-depth look at each subbasin, providing information regarding the results of the North Carolina Division of Water Quality's 2005 Basinwide Management Plan, and providing the UNCW-Aquatic Ecology Laboratory’s (AEL)
assessments of the 2009 sampling year. The UNCW-AEL utilizes ratings that consider
a water body to be of poor quality if the water quality standard for a given parameter is
in violation > 25% of the time, of fair quality if the standard is in violation between 11 and 25% of the time, and good quality if the standard is violated no more than 10% of
the time. UNCW also considerers nutrient loading in water quality assessments, based on published experimental and field scientific findings.
For the 2009 period UNCW rated 100% of the stations as good in terms of chlorophyll a,
likely due to increased river flows and light attenuation compared with the lower water period of 2008. For turbidity 86% of the sites were rated good, 11% fair, and 3% (one station) poor, all located in the upper estuary. Fecal coliform bacteria counts showed
better water quality in 2009 compared to 2008, with 40% of the sites rated as good to
fair compared with 52% in 2008. Using the 5.0 mg/L DO standard for the mainstem river
stations, and the 4.0 mg/L “swamp water” DO standard for the stream stations and blackwater river stations, 39% of the sites were rated poor or fair for dissolved oxygen, somewhat less than in 2008. In addition, by our UNCW standards excessive nitrate and
phosphorus concentrations were problematic at a number of stations (Chapter 3).
Table of Contents
1.0 Introduction...........................................................................………...............…........1
1.1 Site Description................................................………....................................2 1.2 Report Organization……………………………………………………… ……..3
2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River
and Estuary………………………………………………..…………………….....….. ….8 Physical Parameters..…......................………..........................................……....11
Chemical Parameters…....……..……….........................................................…..14
Biological Parameters.......……….....……......................................................…..17
3.0 Water Quality by Subbasin in the Lower Cape Fear River System…………………45
1.0 Introduction
Michael A. Mallin
Center for Marine Science University of North Carolina Wilmington
The Lower Cape Fear River Program is a unique science and education program that
has a mission to develop an understanding of processes that control and influence the
ecology of the Cape Fear River, and to provide a mechanism for information exchange and public education. This program provides a forum for dialogue among the various Cape Fear River user groups and encourages interaction among them. Overall policy is
set by an Advisory Board consisting of representatives from citizen’s groups, local
government, industries, academia, the business community, and regulatory agencies.
This report represents the scientific conclusions of the UNCW researchers participating in this program and does not necessarily reflect opinions of all other program participants. This report focuses on the period January through December 2009.
The scientific basis of the LCFRP consists of the implementation of an ongoing
comprehensive physical, chemical, and biological monitoring program. Another part of the mission is to develop and maintain a data base on the Cape Fear basin and make use of this data to develop management plans. Presently the program has amassed a
14-year (1995-2009) data base that is available to the public. Using this monitoring
data as a framework the program goals also include focused scientific projects and
investigation of pollution episodes. The scientific aspects of the program are carried out by investigators from the University of North Carolina Wilmington Center for Marine Science. The monitoring program was developed by the Lower Cape Fear River
Program Technical Committee, which consists of representatives from UNCW, the
North Carolina Division of Water Quality, The NC Division of Marine Fisheries, the US
Army Corps of Engineers, technical representatives from streamside industries, the City of Wilmington Wastewater Treatment Plants, Cape Fear Community College, Cape Fear River Watch, the North Carolina Cooperative Extension Service, the US
Geological Survey, forestry and agriculture organizations, and others. This integrated
and cooperative program was the first of its kind in North Carolina.
Broad-scale monthly water quality sampling at 16 stations in the estuary and lower river system began in June 1995 (directed by Dr. Michael Mallin). Sampling was increased
to 34 stations in February of 1996, 35 stations in February 1998, and 36 stations in
2005. The Lower Cape Fear River Program added another component concerned with
studying the benthic macrofauna of the system in 1996. This component is directed by Dr. Martin Posey and Mr. Troy Alphin of the UNCW Biology Department and includes the benefit of additional data collected by the Benthic Ecology Laboratory under Sea
Grant and NSF sponsored projects in the Cape Fear Estuary. 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
1
program involved cooperative sampling with the North Carolina Division of Marine Fisheries and the North Carolina Wildlife Resources Commission. The fisheries
program ended in December 1999, but was renewed with additional funds from the Z.
Smith Reynolds Foundation from spring – winter 2000. The regular sampling that was
conducted by UNCW biologists was assumed by the North Carolina Division of Marine Fisheries.
1.1. Site Description
The mainstem of the Cape Fear River is formed by the merging of the Haw and the Deep Rivers in Chatham County in the North Carolina Piedmont. However, its drainage basin reaches as far upstream as the Greensboro area (Fig. 1.1). The mainstem of the
river has been altered by the construction of several dams and water control structures.
In the coastal plain, the river is joined by two major tributaries, the Black and the
Northeast Cape Fear Rivers (Fig. 1.1). These 5th order blackwater streams drain extensive riverine swamp forests and add organic color to the mainstem. The watershed (about 9,149 square miles) is the most heavily industrialized in North
Carolina with 244 permitted wastewater discharges with a permitted flow of
approximately 425 million gallons per day, and (as of 2000) over 1.83 million people
residing in the basin (NCDENR 2005). Approximately 24% of the land use in the watershed is devoted to agriculture and livestock production (NCDENR 2005), with livestock production dominated by swine and poultry operations. Thus, the watershed
receives considerable point and non-point source loading of pollutants. However, the
estuary is a well-flushed system, with flushing time ranging from 1 to 22 days with a
median flushing time of about seven days, much shorter than the other large N.C. estuaries to the north (Ensign et al. 2004).
Water quality is monitored by boat at nine stations in the Cape Fear Estuary (from
Navassa to Southport) and one station in the Northeast Cape Fear Estuary (Table 1.1;
Fig. 1.1). Riverine stations sampled by boat include NC11, AC, DP, IC, and BBT (Table 1.1; Fig. 1.1). NC11 is located upstream of any major point source discharges in the lower river and estuary system, and is considered to be representative of water quality
entering the lower system (we note that the City of Wilmington and portions of
Brunswick County get their drinking water from the river just upstream of Lock and Dan
#1). Station BBT is located on the Black River between Thoroughfare (a stream connecting the Cape Fear and Black Rivers) and the mainstem Cape Fear, and is influenced by both rivers. We consider B210 and NCF117 to represent water quality
entering the lower Black and Northeast Cape Fear Rivers, respectively. Data has also
been collected at stream and river stations throughout the Cape Fear, Northeast Cape
Fear, and Black River watersheds (Table 1.1; Fig. 1.1; Mallin et al. 2001). Data collection at a station in the Atlantic Intracoastal Waterway was initiated in February 1998 to obtain water quality information near the Southport Wastewater Treatment Plant
discharge, and there is one station, SC-CH, sampled for selected parameters on Smith
Creek at Castle Hayne Road (Table 1.1).
2
1.2. Report Organization
This report contains two sections assessing LCFRP data. Section 2 presents an overview of physical, chemical, and biological water quality data from the 36 individual stations, and provides tables of raw data as well as figures showing spatial or temporal
trends. In Section 3 we analyze our data by sub-basin, give information regarding the
NC DWQ's 2005 Basinwide Plan, and make UNCW-based water quality ratings for
dissolved oxygen, turbidity, chlorophyll a, and fecal coliform bacterial abundance. We also utilize other relevant parameters such as nutrient concentrations to aid in these assessments. This section is designed so that residents of a particular sub-basin can
see what the water quality is like in his or her area based on LCFRP data collections.
The LCFRP has a website that contains maps and an extensive amount of past water quality, benthos, and fisheries data gathered by the Program available at: www.uncw.edu/cmsr/aquaticecology/lcfrp/
References Cited Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511. Mallin, M.A., S.H. Ensign, M.R. McIver, G.C. Shank and P.K. Fowler. 2001. Demographic, landscape, and meteorological factors controlling the microbial pollution of coastal waters. Hydrobiologia 460:185-193. NCDENR. 2005. Cape Fear River Basinwide Water Quality Plan. North Carolina Department of Environment and Natural Resources, Division of Water Quality/Planning, Raleigh, NC, 27699-1617.
3
Table 1.1. Description of sampling locations in the Cape Fear Watershed, 2009, including UNCW designation and NCDWQ station designation number.
________________________________________________________________
UNCW St. DWQ No. Location ________________________________________________________________
High order river and estuary stations
NC11 B8360000 At NC 11 bridge on Cape Fear River (CFR) GPS N 34.39663 W 78.26785
AC B8450000 5 km downstream from International Paper on CFR
GPS N 34.35547 W 78.17942
DP B8460000 At DAK America’s Intake above Black River GPS N 34.33595 W 78.05337
IC B9030000 Cluster of dischargers upstream of Indian Cr. on CFR
GPS N 34.30207 W 78.01372 B210 B9000000 Black River at Highway 210 bridge
GPS N 34.43138 W 78.14462
BBT none Black River between Thoroughfare and Cape Fear River GPS N 34.35092 W 78.04857
NCF117 B9580000 Northeast Cape Fear River at Highway 117, Castle Hayne
GPS N 34.36342 W 77.89678
NCF6 B9670000 Northeast Cape Fear River near GE dock GPS N 34.31710 W 77.95383
NAV B9050000 Railroad bridge over Cape Fear River at Navassa
GPS N 34.25943 W 77.98767 HB B9050100 Cape Fear River at Horseshoe Bend
GPS N 34.24372 W 77.96980
BRR B9790000 Brunswick River at John Long Park in Belville GPS N 34.22138 W 77.97868
M61 B9750000 Channel Marker 61, downtown at N.C. State Port
GPS N 34.19377 W 77.95725
4
M54 B7950000 Channel Marker 54, 5 km downstream of Wilmington GPS N 34.13933 W 77.94595
M42 B9845100 Channel Marker 42 near Keg Island
GPS N 34.09017 W 77.93355 M35 B9850100 Channel Marker 35 near Olde Brunswick Towne
GPS N 34.03408 W 77.93943
M23 B9910000 Channel Marker 23 near CP&L intake canal GPS N 33.94560 W 77.96958
M18 B9921000 Channel Marker 18 near Southport
GPS N 33.91297 W 78.01697
SPD B9980000 1000 ft W of Southport WWT plant discharge on ICW GPS N 33.91708 W 78.03717
________________________________________________________________
Stream stations collected from land ________________________________________________________________
SR B8470000 South River at US 13, below Dunn
GPS N 35.15600 W 78.64013
GCO B8604000 Great Coharie Creek at SR 1214 GPS N 34.91857 W 78.38873
LCO B8610001 Little Coharie Creek at SR 1207
GPS N 34.83473 W 78.37087 6RC B8740000 Six Runs Creek at SR 1003 (Lisbon Rd.)
GPS N 34.79357 W 78.31192
BRN B8340050 Browns Creek at NC 87 GPS N 34.61360 W 78.58462
HAM B8340200 Hammonds Creek at SR 1704
GPS N 34.56853 W 78.55147
LVC2 B8441000 on Livingston Creek near Acme GPS N 34.33530 W 78.2011
COL B8981000 Colly Creek at NC 53
GPS N 34.46500 W 78.26553
5
ANC B9490000 Angola Creek at NC 53
GPS N 34.65705 W 77.73485
NC403 B9090000 Northeast Cape Fear below Mt. Olive Pickle at NC403 GPS N 35.17838 W 77.98028
PB B9130000 Panther Branch below Bay Valley Foods
GPS N 35.13445 W 78.13630
GS B9191000 Goshen Swamp at NC 11 GPS N 35.02923 W 77.85143
SAR B9191500 Northeast Cape Fear River near Sarecta
GPS N 34.97970 W 77.86251 LRC B9460000 Little Rockfish Creek at NC 11
GPS N 34.72247 W 77.98145
ROC B9430000 Rockfish Creek at US 117 GPS N 34.71689 W 77.97961
BCRR B9500000 Burgaw Canal at Wright St., above WWTP
GPS N 34.56334 W 77.93481
BC117 B9520000 Burgaw Canal at US 117, below WWTP GPS N 34.56391 W 77.92210
SC-CH B9720000 Smith Creek at Castle Hayne Rd.
GPS N 34.25897 W 77.93872
6
Figure 1.1 Map of the Lower Cape Fear River system and the LCFRP sampling stations.
7
2.0 Physical, Chemical, and Biological Characteristics of the
Lower Cape Fear River and Estuary
Michael A. Mallin and Matthew R. McIver Center for Marine Science University of North Carolina Wilmington
2.1 - Introduction
This section of the report includes a discussion of the physical, chemical, and biological water quality parameters, concentrating on the January-December 2009 Lower Cape Fear
River Program monitoring period. These parameters are interdependent and define the
overall condition of the river. Physical parameters measured during this study included
water temperature, dissolved oxygen, field turbidity and laboratory turbidity, total suspended solids (TSS), salinity, conductivity, pH and light attenuation. The chemical makeup of the Cape Fear River was investigated by measuring the magnitude and
composition of nitrogen and phosphorus in the water. Three biological parameters
including fecal coliform bacteria, chlorophyll a and biochemical oxygen demand were
examined. 2.2 - Materials and Methods
All samples and field parameters collected for the estuarine stations of the Cape Fear
River (NAV down through M18) were gathered on an ebb tide. This was done so that the data better represented the river water flowing downstream through the system rather than the tidal influx of coastal ocean water. Sample collection and analyses were conducted
according to the procedures in the Lower Cape Fear River Program Quality
Assurance/Quality Control (QA/QC) manual. Technical Representatives from the LCFRP
Technical Committee and representatives from the NC Division of Water Quality inspect UNCW laboratory procedures and periodically accompany field teams to verify proper procedures are followed. We note that our previous Livingston Creek station (LVC) has
been discontinued and a new station sampled from the dock of Hexion Specialty
Chemicals near Acme (LVC2) was put into operation in 2005.
Physical Parameters
Water Temperature, pH, Dissolved Oxygen, Turbidity, Salinity, Conductivity
Field parameters were measured at each site using a YSI 6920 (or 6820) multi-parameter water quality sonde displayed on a YSI 650 MDS. Each parameter is measured with individual probes on the sonde. At stations sampled by boat (see Table 1.1) physical
parameters were measured at 0.1 m, the middle of the water column, and at the bottom
(up to 12 m). Occasionally, high flow prohibited the sonde from reaching the actual bottom
and measurements were taken as deep as possible. At the terrestrially sampled stations the physical parameters were measured at a depth of 0.1 m. The Aquatic Ecology
8
Laboratory at the UNCW CMS is State-certified by the N.C. Division of Water Quality to perform field parameter measurements.
Chemical Parameters
Nutrients
All nutrient analyses were performed at the UNCW Center for Marine Science (CMS) for
samples collected prior to January 1996. A local State-certified analytical laboratory was
contracted to conduct all subsequent analyses except for orthophosphate, which is performed at CMS. The following methods detail the techniques used by CMS personnel for orthophosphate analysis.
Orthophosphate (PO4-3)
Water samples were collected ca. 0.1 m below the surface in triplicate in amber 125 mL Nalgene plastic bottles and placed on ice. In the laboratory 50 mL of each triplicate was
filtered through separate1.0 micron pre-combusted glass fiber filters, which were frozen
and later analyzed for chlorophyll a. The triplicate filtrates were pooled in a glass flask,
mixed thoroughly, and approximately 100 mL was poured into a 125 mL plastic bottle to be analyzed for orthophosphate. Samples were frozen until analysis.
Orthophosphate analyses were performed in duplicate using an approved US EPA method
for the Bran-Lubbe AutoAnalyzer (Method 365.5). In this technique the orthophosphate in
each sample reacts with ammonium molybdate and anitmony potassium tartrate in an acidic medium (sulfuric acid) to form an anitmony-phospho-molybdate complex. The complex is then reacted with ascorbic acid and forms a deep blue color. The intensity of
the color is measured at a wavelength of 880 nm by a colorimeter and displayed on a chart
recorder. Standards and spiked samples were analyzed for quality assurance.
Biological Parameters
Fecal Coliform Bacteria
Fecal coliform bacteria were analyzed at a State-certified laboratory contracted by the LCFRP. Samples were collected approximately 0.1 m below the surface in sterile plastic bottles provided by the contract laboratory and placed on ice for no more than six hours
before analysis.
Chlorophyll a
The analytical method used to measure chlorophyll a is described in Welschmeyer (1994)
and US EPA (1997) and was performed by CMS personnel. Chlorophyll a concentrations
were determined utilizing the 1.0 micron filters used for filtering samples for
orthophosphate analysis. All filters were wrapped individually in foil, placed in airtight containers and stored in the freezer. During analysis each filter was immersed in 10 mL of
9
90% acetone for 24 hours, which extracts the chlorophyll a into solution. Chlorophyll a
concentration of each solution was measured on a Turner 10-AU fluorometer. The
fluorometer uses an optimal combination of excitation and emission bandwidth filters which
reduces the errors inherent in the acidification technique. The Aquatic Ecology Laboratory
at the CMS is State-certified by the N.C. Division of Water Quality for the analysis of chlorophyll a.
Biochemical Oxygen Demand (BOD)
Five sites were originally chosen for BOD analysis. One site was located at NC11, upstream of International Paper, and a second site was at AC, about 3 miles downstream of International Paper (Fig.1.1). Two sites were located in blackwater rivers (NCF117 and
B210) and one site (BBT) was situated in an area influenced by both the mainstem Cape
Fear River and the Black River. For the sampling period May 2000-April 2004 additional
BOD data were collected at stream stations 6RC, LCO, GCO, BRN, HAM and COL in the Cape Fear and Black River watersheds. In May 2004 those stations were dropped and sampling commenced at ANC, SAR, GS, N403, ROC and BC117 in the Northeast Cape
Fear River watershed. The procedure used for BOD analysis was Method 5210 in
Standard Methods (APHA 1995). Samples were analyzed for both 5-day and 20-day
BOD. During the analytical period, samples were kept in airtight bottles and placed in an incubator at 20o C. All experiments were initiated within 6 hours of sample collection. Samples were analyzed in duplicate. Dissolved oxygen measurements were made using
a YSI Model 5000 meter that was air-calibrated. No adjustments were made for pH since
most samples exhibited pH values within or very close to the desired 6.5-7.5 range (pH is
monitored during the analysis as well); a few sites have naturally low pH and there was no adjustment for these samples because it would alter the natural water chemistry and affect true BOD.
2.3 - Results and Discussion
This section includes results from monitoring of the physical, biological, and chemical parameters at all stations for the time period January-December 2009. Discussion of the
data focuses both on the river channel stations and stream stations, which sometimes
reflect poorer water quality than mainstem stations. The contributions of the two large
blackwater tributaries, the Northeast Cape Fear River and the Black River, are represented by conditions at NCF117 and B210, respectively. The Cape Fear Region did not experience any significant hurricane activity during this monitoring period (after major
hurricanes in 1996, 1998, and 1999). Therefore this report reflects low to medium flow
conditions for the Cape Fear River and Estuary.
10
Physical Parameters
Water temperature
Water temperatures at all stations ranged from 4.0 to 30.8oC, and individual station annual averages ranged from 16.7 to 20.8oC (Table 2.1). Highest temperatures occurred during July and August and lowest temperatures during February. Stream stations were
generally cooler than river stations, most likely because of shading and lower nighttime air
temperatures affecting the shallower waters.
Salinity
Salinity at the estuarine stations (NAV through SPD) ranged from 0.1 to 34.2 practical
salinity units (psu) and station annual means ranged from 1.3 to 28.4 psu (Table 2.2),
somewhat lower than in 2008. Lowest salinities occurred in December and highest salinities occurred in July. In the upper estuary the annual mean salinity for 2009 was lower than that of the twelve-year average for 1996-2008 for all stations (Figure 2.1),
approximately equal to the long-term mean in mid-estuary, and higher in the lowest
portions of the estuary. Two stream stations, NC403 and PB, had occasional oligohaline
conditions due to discharges from pickle production facilities. Conductivity
Conductivity at the estuarine stations ranged from 0.10 to 52.01 mS/cm and from 0.06 to
12.33 mS/cm at the freshwater stations (Table 2.3). Temporal conductivity patterns followed those of salinity. Dissolved ionic compounds increase the conductance of water, therefore, conductance increases and decreases with salinity, often reflecting river flow
conditions due to rainfall. Conductivity may also reveal point source pollution sources, as
is seen at BC117, which is below a municipal wastewater discharge. Stations PB and
NC403 are below industrial discharges, and often have elevated conductivity. Smith Creek (SC-CH) is an estuarine tidal creek and the conductivity values reflect this (Table 2.3).
pH
pH values ranged from 3.8 to 8.1 and station annual means ranged from 4.1 to 7.9 (Table 2.4). pH was typically lowest upstream due to acidic swamp water inputs and highest downstream as alkaline seawater mixes with the river water. Low pH values at COL
predominate because of naturally acidic blackwater inputs at this near-pristine stream
station.
Dissolved Oxygen
Dissolved oxygen (DO) problems are a major water quality concern in the lower Cape Fear
River and its estuary, and several of the tributary streams (Mallin et al. 1999; 2000; 2001a;
2001b; 2002a; 2002b; 2003; 2004; 2005a; 2006a; 2006b; 2007; 2008). Surface concentrations for all sites in 2009 ranged from 0.6 to 12.2 mg/L and station annual means
11
ranged from 4.2 to 9.3 mg/L (Table 2.5). Average annual DO levels at the river channel and estuarine stations for 2009 were very similar to the average for 1996-2008 (Figure
2.2). River dissolved oxygen levels were lowest during the summer and early fall (Table
2.5), often falling below the state standard of 5.0 mg/L at several river and upper estuary
stations. Working synergistically to lower oxygen levels are two factors: lower oxygen carrying capacity in warmer water and increased bacterial respiration (or biochemical oxygen demand, BOD), due to higher temperatures in summer. Unlike other large North
Carolina estuaries (the Neuse, Pamlico and New River) the Cape Fear estuary rarely
suffers from dissolved oxygen stratification. This is because despite salinity stratification
the oxygen remains well mixed due to strong estuarine gravitational circulation and high freshwater inputs (Lin et al. 2006). Thus, hypoxia in the Cape Fear is present throughout the water column.
There is a dissolved oxygen sag in the main river channel that begins at DP below a paper
mill discharge and persists into the mesohaline portion of the estuary (Fig. 2.2). Mean oxygen levels were highest at the upper river stations NC11 and AC and in the low-to-middle estuary at stations M23 and M35. Lowest mainstem mean 2009 DO levels
occurred at the river and upper estuary stations IC, NAV, HB, BRR and M61 (6.6-6.9
mg/L). NAV and HB were both below 5.0 mg/L on 42% of occasions sampled and BRR
was below on 33%. All river stations upstream (NC11, AC, DP, BBT, and IC) were below 4.0 mg/L on 9% of occasions sampled or less, and rated as Good. Discharge of high BOD waste from the paper/pulp mill just above the AC station (Mallin et al. 2003), as well as
inflow of blackwater from the Northeast Cape Fear and Black Rivers, has in other years
helped to diminish oxygen in the upper estuary. Additionally, algal blooms periodically
form behind Lock and Dam #1, and the chlorophyll a they produce is strongly correlated with BOD at Station NC11 (Mallin et al. 2006b); thus the blooms do contribute to lower DO in the river. As the water reaches the lower estuary higher algal productivity, mixing and
ocean dilution help alleviate oxygen problems.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the mainstem Cape Fear River (NCF117 2009 mean = 6.2, NCF6 = 6.5, B210 2009 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. 1998; 1999; 2006; Mallin 2000). We note that
phosphorus and nitrogen (components of animal manure) levels are positively correlated
with BOD in the blackwater rivers and their major tributaries (Mallin et al. 2006b). In the past the Northeast Cape Fear River has often been more oxygen stressed than the
Black River, and in 2009 Stations NCF117 DO concentrations were again somewhat lower
than at B210 (means 6.2 and 7.2 mg/L, respectively). Several stream stations were
severely stressed in terms of low dissolved oxygen during the year 2009. Stations SR had DO levels below 4.0 mg/L 58% of the occasions sampled, with NC403 and GS 50%, and
12
LVC2 33%, and BCRR 25% (Table 2.5). Some of this can be attributed to low summer water conditions and some potentially to CAFO runoff; however point-source discharges
also likely contribute to low dissolved oxygen levels at NC403 and possibly SR, especially
via nutrient loading (Mallin et al. 2001a; 2002a; 2004). Hypoxia is thus a widespread
problem, with 39% of the sites impacted in 2008.
Field Turbidity
Field turbidity levels ranged from 0 to 167 Nephelometric turbidity units (NTU) and station
annual means ranged from 3 to 27 NTU (Table 2.6). The State standard for estuarine turbidity is 25 NTU. Annual mean turbidity levels for 2009 were lower than the long-term average in the river stations, higher in the upper estuary, then lower in the mid-to-lower
estuary (Fig. 2.3). Highest mean turbidities were at NAV, HB and BRR (25-27 NTU) with
turbidities generally low in the middle to lower estuary (Figure 2.3). Turbidity was
considerably lower in the blackwater tributaries (Northeast Cape Fear River and Black River) than in the mainstem river. Average turbidity levels were low in the freshwater streams, with the exception of BC117 and to a lesser extent BCRR, PB and LRC. The
State standard for freshwater turbidity is 50 NTU.
Note: In addition to the laboratory-analyzed turbidity that are required my NCDWQ for seven locations, the LCFRP uses nephelometers designed for field use, which allows us to acquire in situ turbidity from a natural situation. North Carolina regulatory agencies are
required to use turbidity values from water samples removed from the natural system, put
on ice until arrival at a State-certified laboratory, and analyzed using laboratory
nephelometers. Standard Methods notes that transport of samples and temperature change alters true turbidity readings. Our analysis of samples using both methods shows that lab turbidity is nearly always lower than field turbidity; thus we do not discuss lab
turbidity in this report.
Total Suspended Solids Total suspended solid (TSS) values system wide ranged from 1 to 110 mg/L with station
annual means from 1 to 24 mg/L (Table 2.7). The overall highest values were at NAV and
NCF6. In the stream stations TSS was generally considerably lower than the river and
estuary, except for Station PB. Although total suspended solids (TSS) and turbidity both quantify suspended material in the water column, they do not always go hand in hand. High TSS does not mean high turbidity and vice versa. This anomaly may be explained by
the fact that fine clay particles are effective at dispersing light and causing high turbidity
readings, while not resulting in high TSS. On the other hand, large organic or inorganic
particles may be less effective at dispersing light, yet their greater mass results in high TSS levels. While there is no NC ambient standard for TSS, many years of data from the lower Cape Fear watershed indicates that 25 mg/L can be considered elevated.
13
Light Attenuation
The attenuation of solar irradiance through the water column is measured by a logarithmic
function (k) per meter. The higher this light attenuation coefficient is the more strongly light is attenuated (through absorbance or reflection) in the water column. River and estuary light attenuation coefficients ranged from 0.97 to 6.63/m and station annual means ranged
from 1.84 at M23 to 4.49 /m at NCF6 (Table 2.8). In the Cape Fear system, light is
attenuated by both turbidity and water color.
High light attenuation did not always coincide with high turbidity. Blackwater, though low in turbidity, will attenuate light through absorption of solar irradiance. At NCF6 and BBT,
blackwater stations with moderate turbidity levels, light attenuation was high. Compared to
other North Carolina estuaries the Cape Fear has high average light attenuation. The high
average light attenuation is a major reason why phytoplankton production in the major rivers and the estuary of the LCFR is generally low. Whether caused by turbidity or water color this attenuation tends to limit light availability to the phytoplankton (Mallin et al. 1997;
1999; 2004).
Chemical Parameters – Nutrients
Total Nitrogen
Total nitrogen (TN) is calculated from TKN (see below) plus nitrate; it is not analyzed in the
laboratory. TN ranged from 60 to 14,900 µg/L and station annual means ranged from 474
to 7,920 µg/L (Table 2.9). Mean total nitrogen in 2009 was slightly higher than the
fourteen-year mean at most river stations, but equivalent to the mean in the mid-to-lower
estuary (Figure 2.4). Previous research (Mallin et al. 1999) has shown a positive
correlation between river flow and TN in the Cape Fear system. In the main river total nitrogen concentrations were highest between NC11 and AC, entering the system, then remained fairly constant down the river and declined from mid-estuary into the lower
estuary, most likely reflecting uptake of nitrogen into the food chain through algal
productivity and subsequent grazing by planktivores as well as through dilution and marsh
denitrification. The blackwater rivers maintained TN concentrations considerably lower than those found in the mainstem Cape Fear River. One stream station, BC117, had a
very high mean of 7,920 µg/L, likely from the upstream Town of Burgaw wastewater
discharge. PB, ROC, NC403 and ANC also had comparatively high TN values among the
stream stations. 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 system wide ranged from 10 (detection limit)
to 14,100 µg/L and station annual means ranged from 67 to 7,166 µg/L (Table 2.10). The
highest average riverine nitrate levels were at NC11 and AC (both 773 µg/L) indicating that
much of this nutrient is imported from upstream. Moving downstream, nitrate levels
14
decrease most likely as a result of uptake by primary producers, microbial denitrification in riparian marshes and tidal dilution. Despite this, the rapid flushing of the estuary (Ensign
et al. 2004) permits sufficient nitrate to enter the coastal ocean in the plume and contribute
to offshore productivity (Mallin et al. 2005b). Nitrate can limit phytoplankton production in
the lower estuary in summer (Mallin et al. 1999). The blackwater rivers carried lower loads of nitrate compared to the mainstem Cape Fear stations; i.e. the Northeast Cape Fear
River (NCF117 mean = 253 µg/L) and the Black River (B210 = 225 µg/L). No clear
temporal pattern was observable for nitrate.
Several stream stations showed high levels of nitrate on occasion including BC117, ROC, 6RC, NC403, PB and LCO. PB and NC403 are downstream of industrial wastewater
discharges and ROC and 6RC primarily receive non-point agricultural or animal waste
drainage. BC117 always showed very high nitrate levels. The Town of Burgaw
wastewater plant, upstream of BC117, has no nitrate discharge limits. Over the past
several years a considerable number of experiments have been carried out by UNCW researchers to assess the effects of nutrient additions to water collected from blackwater
streams and rivers (i.e. the Black and Northeast Cape Fear Rivers, and Colly and Great
Coharie Creeks). These experiments have collectively found that additions of nitrogen (as
either nitrate, ammonium, or urea) significantly stimulate phytoplankton production and
BOD increases. Critical levels of these nutrients were in the range of 0.2 to 0.5 mg/L as N (Mallin et al. 1998; Mallin et al. 2001a; Mallin et al. 2002a, Mallin et al. 2004). Thus, we
conservatively consider nitrate concentrations exceeding 0.5 mg/L as N in Cape Fear
watershed streams to be potentially problematic to the stream’s environmental health.
Ammonium
Ammonium concentrations ranged from 5 (detection limit) to 1,710 µg/L and station annual
means ranged from 15 to 391 µg/L (Table 2.11). River areas with the highest mean
ammonium levels this monitoring period included AC, which is below a pulp mill discharge, and M54, located downstream of the Wilmington South Side Wastewater Treatment Plant
discharge. Ocean dilution and biological uptake accounts for decreasing levels in the
lower estuary. At the stream stations, areas with periodic high levels of ammonium include
BCRR, BC117, LRC, NC403 and especially PB (below a point source), which had the
highest mean and median ammonium concentrations in the system (Table 2.11).
Total Kjeldahl Nitrogen
Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen
plus ammonium. TKN ranged from 50 to 4,900 µg/L and station annual means ranged
from 400 to 1,575 µg/L (Table 2.12). TKN concentration decreases ocean-ward through
the estuary, likely due to ocean dilution and food chain uptake of nitrogen. One notably
elevated peak of 4,900 µg/L of TN was seen at PB in July; this station was located
downstream of an industrial point source discharge and had the highest mean concentrations for the system. Station ANC also had high mean and median
concentrations. No other unusual peaks in TKN were seen in the data.
15
Total Phosphorus
Total phosphorus (TP) concentrations ranged from below detection limit to 2,950 µg/L and
station annual means ranged from 38 to 915 µg/L (Table 2.13). Mean TP for 2009 was
approximately equal to the fourteen-year mean in most areas (Figure 2.5). In the river TP
is highest at the upper riverine channel stations and declines downstream into the estuary.
Some of this decline is attributable to the settling of phosphorus-bearing suspended sediments, yet incorporation of phosphorus into bacteria and algae is also responsible. A temporal pattern of higher summer TP is a result of increasing orthophosphate during the
summer.
The experiments discussed above in the nitrate subsection also involved additions of phosphorus, either as inorganic orthophosphate or a combination of inorganic plus organic P. The experiments showed that additions of P exceeding 0.5 mg/L led to significant
increases in bacterial counts, as well as significant increases in BOD over control. Thus,
we consider concentrations of phosphorus above 0.5 mg/L (500 µg/L ) to be potentially
problematic to blackwater streams. Streams periodically exceeding this critical concentration included BC117, GCO, ROC, PB and NC403. Some of these stations
(BC117, NC403, PB) are downstream of industrial or wastewater discharges, while GCO
and ROC are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 1,720 µg/L and station annual means ranged
from 8 to 702 µg/L (Table 2.14). Much of the orthophosphate load is imported into the
Lower Cape Fear system from upstream areas, as NC11 or AC typically 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 particle attachment; thus high levels of turbidity at the uppermost river stations may be
an important factor in the high orthophosphate levels. Turbidity declines toward the lower
estuary because of settling, and orthophosphate concentration also declines. In the estuary, primary productivity helps reduce orthophosphate concentrations by assimilation
into biomass. Orthophosphate levels typically reach maximum concentrations during
summertime, when anoxic sediment releases bound phosphorus. Also, in the Cape Fear
Estuary, summer algal productivity is limited by nitrogen, thereby allowing the
accumulation of orthophosphate (Mallin et al. 1997; 1999). In spring, productivity in the estuary is usually limited by phosphorus (Mallin et al. 1997; 1999).
The stream station BC117 had very high orthophosphate levels, and ROC, GCO and ANC
had comparatively high levels. BC117 is below a municipal wastewater discharge, and
ROC, GCO and ANC are impacted by agriculture/animal waste runoff.
16
Chemical Parameters - EPA Priority Pollutant Metals
The LCFRP had previously sampled for water column metals (EPA Priority Pollutant
Metals) on a bimonthly basis. However, as of 2007 this requirement was suspended by
the NC Division of Water Quality and these data are no longer collected by the LCFRP. Biological Parameters
Chlorophyll a
During this monitoring period in most locations chlorophyll a was low, except for elevated
concentrations in July and August at many locations (Table 2.15). At many of the river and
estuarine stations chlorophyll a for 2009 was considerably higher than the fourteen-year
mean for those sites (Figure 2.6). However, an unusual and important algal bloom
occurred in September at Station NC11, with chlorophyll a levels of 61 µg/L, the highest we have ever recorded in riverine or estuarine sampling on the Cape Fear. We note that
at this site it has been demonstrated that chlorophyll a biomass is significantly correlated
with biochemical oxygen demand (BOD5 – Mallin et al. 2006b). High chlorophyll at NC11
may represent remnants of algal blooms forming in the more lentic (lake-like) conditions
found above Lock and Dam #1. What was even more important was that this was a bloom of cyanobacteria (blue-green algae) called Microcystis aeruginosa. Significant
concentrations of toxin (72.94 µg/L of microcystin, a liver toxin) were detected in the bloom
as well by the North Carolina Department of health and Human Services (NCDHHS memo
dated September 25, 2010). The World Health Organization has recommended a limit of 1
µg/L of microcystins for drinking water to protect human health (Burkholder 2002). The bloom persisted for a number of weeks before dissipating. The presence of the bloom
affected Brunswick County water treatment in that county and they contracted with UNCW
LCFRP to collect additional water samples to keep them informed of chlorophyll a
concentrations. We note that the City of Wilmington also receives their drinking water from
the river above Lock and Dam #1.
System wide, chlorophyll a ranged from undetectable to 438 µg/L and station annual
means ranged from 1–45 µg/L. Production of chlorophyll a biomass is usually low to
moderate in the rivers and estuary primarily because of light limitation by turbidity in the mainstem and high organic color and low inorganic nutrients in the blackwater rivers.
Spatially, highest values are normally found in the mid-to-lower estuary stations because
light becomes more available downstream of the estuarine turbidity maximum (Table 2.6).
On average, flushing time of the Cape Fear estuary is rapid, ranging from 1-22 days with a median of 6.7 days (Ensign et al. 2004). This does not allow for much settling of
suspended materials, leading to light limitation of phytoplankton production. However,
under lower-than-average flows there is generally clearer water through less suspended
material and less blackwater swamp inputs. For the growing season May-September,
long-term (1995-2009) average monthly flow at Lock and Dam #1 was 3,704 CFS (USGS data; http://nc.water.usgs.gov/realtime/real_time_cape_fear.html), whereas for 2009 it was
17
1,898 CFS. Thus, chlorophyll a concentrations in the estuary were larger than the average
for the preceding eleven years (Figure 2.6).
Substantial phytoplankton blooms occasionally occur at the stream stations, with a few
occurring June through August in 2009 (Table 2.15). These streams are generally shallow, so vertical mixing does not carry phytoplankton cells down below the critical depth where respiration exceeds photosynthesis. Thus, when lower flow conditions prevail,
elevated nutrient conditions (such as are periodically found in these stream stations) can
lead to algal blooms. In areas where the forest canopy opens up large blooms can occur.
When blooms occur in blackwater streams they can become sources of BOD upon death and decay, reducing further the low summer dissolved oxygen conditions common to these waters (Mallin et al. 2001a; 2002a; 2004; 2006b). Stream algal blooms exceeding the
State standard of 40 µg/L in 2009 occurred at GS, PB, NC403 and SR (Table 2.15).
Biochemical Oxygen Demand For the mainstem river, median annual five-day biochemical oxygen demand (BOD5)
concentrations were approximately equivalent between NC11 and AC, suggesting that in
2009 (as was the case with 2007 and 2008) there as little discernable effect of BOD
loading from the nearby pulp/paper mill inputs (Table 2.16). BOD was somewhat lower during the winter than summer at most (but not all) sites.
Results of 2009 BOD analyses from several stream stations in the Northeast Cape Fear
River watershed can be seen in Table 2.16. LVC2, GS, BC117 and N403 all showed large
(> 3.5 mg/L) individual BOD5 measurements during 2009, particularly during summer. Stations BC117, LVC2 and N403 are below point sources, but GS is a non-point runoff area.
Fecal Coliform Bacteria
Fecal coliform (FC) bacterial counts ranged from 1 to >20,000 CFU/100 mL and station annual geometric means ranged from 8 to 492 CFU/100 mL (Table 2.17). The state
human contact standard (200 CFU/100 mL) was exceeded at the mainstem sites only
rarely in 2009, in July and November. Geometric mean fecal coliform counts in 2009 in the
Cape Fear, Black, and Northeast Cape Fear Rivers as well as the estuary were high compared with the fourteen-year average (Figure 2.7).
During 2009 BCRR exceeded the state standard 83% of the time; PB 75%, BC117 and
BRN 58%, LRC, ROC and HAM 50%, SAR 42%, LVC2 33%, 6RC and SR 25% of the
time. BC117, LVC2 and PB are located below point source discharges and the other sites are primarily influenced by non-point source pollution. Overall, elevated fecal coliform counts are problematic in this system, with 40% of the stations impacted in 2009, an
improvement from the previous year 2008.
2.4 - References Cited
18
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed. American Public Health Association, Washington, D.C.
Burkholder. J.M. 2002. Cyanobacteria. In “Encyclopedia of Environmental Microbiology” (G. Bitton, Ed.), pp 952-982. Wiley Publishers, New York. Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511.
Lin, J. L. Xie, L.J. Pietrafesa, J. Shen, M.A. Mallin and M.J. Durako. 2006. Dissolved oxygen stratification in two microtidal partially-mixed estuaries. Estuarine, Coastal and Shelf Science. 70:423-437.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1997. Nutrient limitation and eutrophication potential in the Cape Fear and New River Estuaries.
Report No. 313. Water Resources Research Institute of the University of North Carolina,
Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 1998. Effect of organic and inorganic nutrient loading on photosynthetic and heterotrophic plankton communities in
blackwater rivers. Report No. 315. Water Resources Research Institute of the
University of North Carolina, Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1999. Alternation of factors limiting phytoplankton production in the Cape Fear Estuary. Estuaries
22:985-996.
Mallin, M.A. 2000. Impacts of industrial-scale swine and poultry production on rivers and estuaries. American Scientist 88:26-37.
Mallin, M.A., M.H. Posey, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S. Williams, M.L.
Moser and J.F. Merritt. 2000. Environmental Assessment of the Lower Cape Fear River
System, 1999-2000. CMS Report No. 00-01, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001a. Effect of nitrogen and
phosphorus loading on plankton in Coastal Plain blackwater streams. Journal of
Freshwater Ecology 16:455-466. Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S.
Williams, M.L. Moser and J.F. Merritt. 2001b. Environmental Assessment of the Lower
Cape Fear River System, 2000-2001. CMS Report No. 01-01, Center for Marine
Science, University of North Carolina at Wilmington, Wilmington, N.C. Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002a. Seeking science-based
nutrient standards for coastal blackwater stream systems. Report No. 341. Water
Resources Research Institute of the University of North Carolina, Raleigh, N.C.
19
Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, H.A. CoVan, T.D. Alphin, M.S.
Williams and J.F. Merritt. 2002b. Environmental Assessment of the Lower Cape Fear
River System, 2001-2002. CMS Report No. 02-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C. Mallin, M.A., M.R. McIver, H.A. Wells, M.S. Williams, T.E. Lankford and J.F. Merritt. 2003.
Environmental Assessment of the Lower Cape Fear River System, 2002-2003. CMS
Report No. 03-03, Center for Marine Science, University of North Carolina at
Wilmington, Wilmington, N.C. Mallin, M.A., M.R. McIver, S.H. Ensign and L.B. Cahoon. 2004. Photosynthetic and heterotrophic impacts of nutrient loading to blackwater streams. Ecological Applications 14:823-838. Mallin, M.A., M.R. McIver, T.D. Alphin, M.H. Posey and J.F. Merritt. 2005a. Environmental Assessment of the Lower Cape Fear River System, 2003-2004. CMS Report No. 05-02, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C. Mallin, M.A., L.B. Cahoon and M.J. Durako. 2005b. Contrasting food-web support bases for adjoining river-influenced and non-river influenced continental shelf ecosystems. Estuarine, Coastal and Shelf Science 62:55-62. Mallin, M.A., M.R. McIver and J.F. Merritt. 2006a. Environmental Assessment of the Lower Cape Fear River System, 2005. CMS Report No. 06-02, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., V.L. Johnson, S.H. Ensign and T.A. MacPherson. 2006b. Factors contributing
to hypoxia in rivers, lakes and streams. Limnology and Oceanography 51:690-701. Mallin, M.A., M.R. McIver and J.F. Merritt. 2007. Environmental Assessment of the Lower
Cape Fear River System, 2006. CMS Report No. 07-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2008. Environmental Assessment of the Lower
Cape Fear River System, 2007. CMS Report No. 08-03, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
U.S. EPA 1997. Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices, 2nd Ed. EPA/600/R-97/072. National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental
Protection Agency, Cincinnati, Ohio.
Welschmeyer, N.A. 1994. Fluorometric analysis of chlorophyll a in the presence of chlorophyll b and phaeopigments. Limnology and Oceanography 39:1985-1993.
20
Table 2.1 Water temperature (oC) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 10.2 10.6 10.7 11.3 11.0 11.6 12.2 12.1 12.3 12.1 JAN 10.4 10.8 11.2 11.6 11.4 13.2
FEB 10.0 10.4 10.6 9.9 10.6 10.7 10.7 10.9 10.6 10.5 FEB 7.7 7.8 7.7 7.7 7.8 8.5
MAR 16.9 16.9 16.1 16.5 16.0 15.9 16.0 16.6 16.9 16.4 MAR 10.8 11.0 11.3 12.1 12.0 13.8
APR 18.5 18.5 18.5 18.4 18.4 18.5 18.6 18.3 17.8 19.4 APR 16.1 16.2 16.1 16.1 16.2 16.9
MAY 25.3 25.1 25.0 24.9 24.7 24.8 24.9 24.7 23.7 24.9 MAY 23.8 23.9 23.7 23.7 23.7 24.0
JUN 26.0 26.4 26.5 26.4 26.5 26.3 26.9 26.5 26.3 27.6 JUN 26.2 26.0 26.0 26.0 26.2 25.6
JUL 28.6 28.7 29.2 28.9 28.7 28.8 28.9 28.1 28.0 28.1 JUL 30.8 29.4 28.4 28.5 29.9 29.0
AUG 29.6 29.6 29.6 29.4 29.2 29.0 28.9 29.0 28.6 29.1 AUG 30.1 30.7 30.0 30.7 29.8 30.0
SEP 27.7 28.0 27.8 28.3 27.9 27.4 27.4 27.3 27.1 27.5 SEP 27.1 27.6 27.0 26.5 26.9 27.2
OCT 23.1 23.1 22.9 23.3 23.4 23.2 23.7 23.8 24.3 24.0 OCT 23.0 23.0 21.8 21.8 22.4 22.9
NOV 13.9 14.0 14.0 14.9 15.2 15.7 16.4 16.9 17.0 16.7 NOV 18.5 18.9 18.8 18.8 19.1 19.4
DEC 12.3 12.4 12.5 13.5 13.5 13.5 13.9 14.0 14.4 13.8 DEC 10.8 10.9 11.3 12.1 11.8 12.6
mean 20.2 20.3 20.3 20.5 20.4 20.5 20.7 20.7 20.6 20.8 mean 19.6 19.7 19.4 19.6 19.8 20.3
std dev 7.4 7.3 7.4 7.2 7.1 6.9 6.8 6.6 6.5 6.8 std dev 8.3 8.2 7.8 7.6 7.8 7.2
max 29.6 29.6 29.6 29.4 29.2 29.0 28.9 29.0 28.6 29.1 max 30.8 30.7 30.0 30.7 29.9 30.0
min 10.0 10.4 10.6 9.9 10.6 10.7 10.7 10.9 10.6 10.5 min 7.7 7.8 7.7 7.7 7.8 8.5
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 11.2 10.0 9.9 9.6 8.5 9.4 12.3 11.2 12.4 JAN 9.5 9.2 10.0 8.9 12.3 11.1 JAN 11.9 10.9 10.9 11.0 13.0
FEB 15.5 14.6 16.2 14.3 14.6 13.9 13.2 13.8 12.8 FEB 7.0 6.5 6.8 6.7 8.0 7.3 FEB 8.1 5.7 5.7 4.0 7.7
MAR 8.4 5.7 7.2 7.2 5.5 6.0 5.9 5.8 4.3 MAR 4.6 4.0 4.2 5.1 5.5 5.3 MAR 7.8 6.1 6.1 5.1 8.8
APR 16.1 16.5 17.2 16.7 16.1 16.9 16.6 15.9 15.4 APR 18.8 18.8 19.7 19.4 19.5 18.9 APR 16.8 16.7 16.7 15.4 16.7
MAY 23.3 22.4 22.6 22.5 21.6 22.3 23.1 22.3 22.2 MAY 22.5 23.1 23.6 21.9 22.1 21.5 MAY 23.8 23.5 23.5 20.7 23.7
JUN 24.9 26.6 26.4 26.9 27.4 24.5 24.4 22.4 22.8 JUN 23.6 24.0 25.1 23.5 23.7 23.0 JUN 25.8 25.8 25.8 21.9 26.2
JUL 25.7 25.3 25.2 25.5 25.9 24.0 25.5 24.1 23.6 JUL 24.7 24.7 25.7 24.4 24.1 23.2 JUL 29.3 27.7 27.7 23.6 28.0
AUG 26.5 26.8 26.2 27.2 27.5 26.7 25.9 25.6 25.1 AUG 26.6 26.6 26.1 25.1 25.8 25.5 AUG 29.2 29.2 29.2 26.8 29.2
SEP 22.6 21.6 22.5 22.9 22.4 22.9 22.1 22.8 21.9 SEP 21.8 22.4 22.6 22.1 22.1 21.3 SEP 24.4 23.8 23.7 25.3
OCT 19.6 19.5 18.8 19.2 20.8 18.5 18.5 18.9 18.9 OCT 19.1 18.9 19.0 18.4 18.2 17.4 OCT 20.6 20.0 20.0 18.6 22.7
NOV 15.7 14.6 15.0 14.4 14.5 15.5 14.7 15.1 14.1 NOV 16.8 17.0 17.0 16.3 16.4 16.3 NOV 18.6 16.3 16.3 14.2 19.0
DEC 14.7 13.7 13.0 13.5 12.7 13.9 14.3 14.8 14.5 DEC 8.6 8.4 7.9 8.1 9.3 9.2 DEC 11.7 11.3 11.3 11.7 12.8
mean 18.7 18.1 18.4 18.3 18.1 17.9 18.0 17.7 17.3 mean 17.0 17.0 17.3 16.7 17.3 16.7 mean 19.0 18.1 17.6 16.4 19.4
std dev 6.0 6.7 6.4 6.7 7.3 6.4 6.3 6.0 6.1 std dev 7.6 7.9 8.0 7.5 6.9 6.8 std dev 7.8 8.2 8.4 7.4 7.5
max 26.5 26.8 26.4 27.2 27.5 26.7 25.9 25.6 25.1 max 26.6 26.6 26.1 25.1 25.8 25.5 max 29.3 29.2 29.2 26.8 29.2
min 8.4 5.7 7.2 7.2 5.5 6.0 5.9 5.8 4.3 min 4.6 4.0 4.2 5.1 5.5 5.3 min 7.8 5.7 5.7 4.0 7.7
21
Table 2.2 Salinity (psu) during 2009 at the Lower Cape Fear River Program estuarine stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6 SC-CH
JAN 0.1 0.1 0.1 0.6 1.2 4.4 13.2 17.8 29.5 21.5 0.3 0.7
FEB 2.5 3.6 2.8 5.6 9.2 16.9 21.0 26.6 31.4 26.6 1.1 0.5
MAR 0.1 0.1 0.1 0.7 2.5 5.8 9.9 25.6 28.5 21.6 0.1 0.5
APR 0.1 0.1 0.2 3.5 4.1 6.0 9.7 21.6 26.3 26.4 0.1 0.2
MAY 0.1 0.6 0.9 4.4 8.6 12.2 18.3 27.7 32.0 26.8 0.6 3.7
JUN 0.1 0.1 2.4 6.1 7.3 10.3 12.5 21.7 24.5 29.4 0.1 2.1
JUL 4.2 7.9 9.4 11.4 15.4 19.0 23.1 28.6 32.5 31.3 9.8 10.9
AUG 2.3 4.1 7.7 10.3 13.6 15.9 18.5 26.3 32.2 33.6 1.0 5.9
SEP 0.4 3.3 6.1 10.5 12.8 14.2 16.6 23.7 27.4 30.0 4.1 11.0
OCT 5.6 5.4 5.4 7.5 10.7 13.3 21.4 26.9 34.2 31.0 6.1 4.1
NOV 0.1 0.1 0.1 0.6 1.9 3.8 10.1 14.7 20.7 21.7 14.5 13.8
DEC 0.1 0.2 0.3 3.1 4.9 6.5 9.7 15.2 21.4 21.6 0.1 0.1
mean 1.3 2.1 3.0 5.4 7.7 10.7 15.3 23.0 28.4 26.8 3.2 4.5
std dev 1.9 2.7 3.4 3.9 4.8 5.3 5.1 4.9 4.4 4.4 4.7 4.9
max 5.6 7.9 9.4 11.4 15.4 19.0 23.1 28.6 34.2 33.6 14.5 13.8
min 0.1 0.1 0.1 0.6 1.2 3.8 9.7 14.7 20.7 21.5 0.1 0.1
22
0
5
10
15
20
25
30
NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6
Sa
l
i
n
i
t
y
(
p
s
u
)
Figure 2.1 Salinity at the Lower Cape Fear River Program estuarine stations, 1995-2008
versus 2009.
1995-2008
2009
23
Table 2.3 Conductivity (mS/cm) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 0.10 0.11 0.15 1.14 2.37 8.02 21.89 28.86 45.59 34.22 JAN 0.11 0.21 0.13 0.13 0.13 0.60
FEB 4.66 6.63 5.21 9.83 15.74 27.54 33.51 41.58 48.43 41.67 FEB 0.12 0.12 0.13 0.12 0.14 2.16
MAR 0.12 0.14 0.18 1.31 4.65 9.97 16.71 39.83 44.14 34.35 MAR 0.11 0.12 0.13 0.11 0.11 0.19
APR 0.12 0.14 0.51 6.38 7.55 10.60 16.44 34.32 41.03 41.06 APR 0.11 0.12 0.12 0.09 0.11 0.22
MAY 0.24 1.22 1.81 7.98 14.76 20.52 29.64 42.99 49.08 41.76 MAY 0.11 0.12 0.18 0.16 0.17 1.19
JUN 0.18 0.30 4.56 10.70 12.73 17.54 20.88 34.63 38.63 45.59 JUN 0.12 0.30 0.18 0.12 0.16 0.20
JUL 7.72 13.69 16.13 19.27 25.41 30.77 36.63 44.24 49.75 48.11 JUL 0.11 0.26 0.20 0.20 0.26 16.71
AUG 4.39 7.52 13.43 17.61 22.66 26.15 30.02 41.26 49.34 51.24 AUG 0.14 0.15 0.20 0.19 0.23 1.98
SEP 0.86 6.11 10.89 17.85 21.48 23.47 27.06 37.48 42.66 46.48 SEP 0.11 0.13 0.18 0.16 0.18 7.45
OCT 9.85 9.39 9.52 12.95 18.01 21.97 34.15 41.92 52.01 47.58 OCT 0.13 0.36 0.20 0.20 0.21 10.55
NOV 0.12 0.13 0.18 1.24 3.55 6.95 17.14 24.14 32.93 34.50 NOV 0.17 0.30 0.28 0.28 5.63 23.65
DEC 0.16 0.31 0.66 5.74 8.68 11.33 16.41 24.90 34.05 34.38 DEC 0.09 0.10 0.10 0.09 0.09 0.09
mean 2.38 3.81 5.27 9.33 13.13 17.90 25.04 36.35 43.97 41.75 mean 0.12 0.19 0.17 0.15 0.62 5.41
std dev 3.45 4.68 5.79 6.57 7.83 8.30 7.67 7.04 6.29 6.18 std dev 0.02 0.09 0.05 0.06 1.58 7.77
max 9.85 13.69 16.13 19.27 25.41 30.77 36.63 44.24 52.01 51.24 max 0.17 0.36 0.28 0.28 5.63 23.65
min 0.10 0.11 0.15 1.14 2.37 6.95 16.41 24.14 32.93 34.22 min 0.09 0.10 0.10 0.09 0.09 0.09
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 0.14 0.17 0.16 0.34 1.01 0.15 0.16 0.42 0.26 JAN 0.13 0.09 0.11 0.08 0.11 0.14 JAN 0.16 0.09 0.08 0.13 1.36
FEB 0.11 0.18 0.16 0.38 2.04 0.16 0.15 0.50 0.29 FEB 0.13 0.09 0.13 0.08 0.11 0.14 FEB 0.16 0.09 0.08 0.12 0.92
MAR 0.13 0.14 0.14 0.23 0.90 0.14 0.12 0.28 0.16 MAR 0.10 0.07 0.09 0.06 0.09 0.10 MAR 0.16 0.09 0.08 0.16 1.02
APR 0.13 0.15 0.16 0.32 1.03 0.17 0.07 0.48 0.18 APR 0.12 0.07 0.10 0.07 0.09 0.13 APR 0.14 0.08 0.07 0.14 0.43
MAY 0.10 0.17 0.18 0.50 1.87 0.14 0.13 0.28 0.19 MAY 0.13 0.16 0.17 0.10 0.11 0.16 MAY 0.15 0.08 0.07 0.16 6.79
JUN 0.11 0.19 0.23 0.94 9.74 0.17 0.17 0.57 0.23 JUN 0.13 0.09 0.17 0.09 0.09 0.09 JUN 0.12 0.08 0.07 0.10 3.97
JUL 0.15 0.31 0.24 1.17 12.33 0.27 0.29 0.63 0.21 JUL 0.14 0.09 0.32 0.13 0.12 0.20 JUL 0.17 0.09 0.07 0.12 18.52
AUG 0.11 0.29 0.22 0.68 1.26 0.18 0.10 0.47 0.24 AUG 0.12 0.09 0.15 0.06 0.13 0.22 AUG 0.15 0.14 0.07 0.13 10.47
SEP 0.11 0.11 0.21 0.52 2.23 0.10 0.13 0.86 0.25 SEP 0.14 0.09 0.17 0.09 0.13 0.25 SEP 0.13 0.09 0.17 18.61
OCT 0.11 0.28 0.26 0.75 6.96 0.13 0.19 0.57 0.26 OCT 0.13 0.08 0.10 0.08 0.11 0.22 OCT 0.10 0.09 0.06 0.11 7.38
NOV 0.12 0.21 0.20 0.29 1.23 0.13 0.14 0.31 0.13 NOV 0.16 0.10 0.20 0.10 0.14 0.24 NOV 0.15 0.12 0.08 0.16 22.72
DEC 0.10 0.13 0.14 0.13 0.55 0.05 0.12 0.21 0.12 DEC 0.15 0.10 0.11 0.08 0.15 0.13 DEC 0.10 0.10 0.11 0.08 0.19
mean 0.12 0.19 0.19 0.52 3.43 0.15 0.15 0.46 0.21 mean 0.13 0.09 0.15 0.09 0.12 0.17 mean 0.14 0.10 0.08 0.13 7.70
std dev 0.02 0.06 0.04 0.31 3.97 0.05 0.05 0.18 0.05 std dev 0.02 0.02 0.06 0.02 0.02 0.05 std dev 0.02 0.02 0.01 0.03 8.11
max 0.15 0.31 0.26 1.17 12.33 0.27 0.29 0.86 0.29 max 0.16 0.16 0.32 0.13 0.15 0.25 max 0.17 0.14 0.11 0.17 22.72
min 0.10 0.11 0.14 0.13 0.55 0.05 0.07 0.21 0.12 min 0.10 0.07 0.09 0.06 0.09 0.09 min 0.10 0.08 0.06 0.08 0.19
24
Table 2.4 pH during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 6.9 7.0 7.4 7.5 8.1 8.0 7.9 8.0 8.0 7.8 JAN 6.6 7.1 6.9 6.7 6.8 6.7
FEB 7.2 7.2 7.6 7.4 7.8 7.9 8.0 8.0 7.9 7.9 FEB 6.6 6.9 6.9 6.8 6.9 6.8
MAR 6.9 7.0 7.2 7.1 7.4 7.6 7.8 8.0 8.0 7.9 MAR 7.1 7.1 7.1 6.9 6.9 6.6
APR 7.9 7.1 7.2 7.2 7.7 7.6 7.9 7.9 7.9 7.7 APR 6.9 7.0 7.0 6.4 6.7 6.8
MAY 7.0 7.0 7.3 7.3 7.4 7.7 7.9 8.0 8.0 7.9 MAY 6.8 6.8 6.8 6.7 6.8 6.8
JUN 6.7 6.7 6.7 6.9 7.1 7.2 7.4 7.8 7.9 7.5 JUN 6.7 7.1 6.8 6.5 6.7 6.5
JUL 7.0 7.1 7.1 7.4 7.5 7.7 7.9 7.9 8.0 7.8 JUL 6.9 7.0 6.8 6.8 6.9 7.1
AUG 7.0 7.1 7.1 7.2 7.3 7.5 7.8 7.9 7.9 7.8 AUG 6.9 7.0 6.9 6.9 6.9 6.8
SEP 6.7 6.8 7.0 7.1 7.2 7.4 7.5 7.8 7.8 7.6 SEP 6.6 6.8 6.7 6.6 6.7 6.7
OCT 6.9 7.0 7.1 7.2 7.4 7.5 7.7 7.8 8.0 7.8 OCT 6.7 7.2 6.8 6.7 6.8 6.7
NOV 6.7 6.8 7.1 6.8 7.5 7.7 7.6 7.7 7.8 7.7 NOV 6.7 7.1 6.9 6.9 6.9 7.2
DEC 7.0 7.0 7.4 6.9 7.6 7.6 7.7 8.0 7.9 7.7 DEC 6.6 6.7 6.7 6.3 6.5 6.1
mean 7.0 7.0 7.2 7.2 7.5 7.6 7.8 7.9 7.9 7.8 mean 6.8 7.0 6.9 6.7 6.8 6.7
std dev 0.3 0.1 0.2 0.2 0.3 0.2 0.2 0.1 0.1 0.1 std dev 0.2 0.2 0.1 0.2 0.1 0.3
max 7.9 7.2 7.6 7.5 8.1 8.0 8.0 8.0 8.0 7.9 max 7.1 7.2 7.1 6.9 6.9 7.2
min 6.7 6.7 6.7 6.8 7.1 7.2 7.4 7.7 7.8 7.5 min 6.6 6.7 6.7 6.3 6.5 6.1
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 6.2 6.6 6.6 6.9 6.7 7.2 7.0 7.0 6.4 JAN 6.6 6.3 6.4 5.9 6.5 6.6 JAN 6.0 5.7 3.9 6.7 6.0
FEB 5.8 6.6 6.7 6.8 6.8 7.2 7.1 7.3 7.3 FEB 6.4 6.3 6.4 6.0 6.5 6.7 FEB 6.4 6.1 3.9 7.4 7.4
MAR 5.5 6.5 6.7 6.5 6.4 6.9 6.6 7.2 7.5 MAR 6.2 5.5 6.4 6.2 6.4 6.5 MAR 6.7 6.2 3.8 6.6 7.2
APR 6.3 6.7 6.7 6.5 6.7 7.3 6.9 7.4 6.8 APR 6.8 6.1 6.4 6.1 6.7 6.8 APR 6.5 6.2 4.0 6.6 6.8
MAY 5.8 6.6 6.6 6.4 6.6 7.1 6.8 7.3 7.3 MAY 7.0 7.1 6.9 6.4 7.0 7.0 MAY 6.7 6.3 4.2 6.9 7.0
JUN 6.2 6.9 6.5 6.5 7.3 7.4 7.1 7.4 6.8 JUN 7.0 6.8 6.9 6.1 6.6 6.5 JUN 6.3 6.0 4.0 6.8 6.7
JUL 6.5 7.1 6.6 6.5 7.5 7.7 7.1 7.4 6.7 JUL 7.0 6.8 7.1 6.4 7.1 7.3 JUL 6.6 6.3 4.0 6.8 7.0
AUG 6.2 7.0 6.3 6.4 6.8 7.1 6.6 7.4 6.7 AUG 7.1 6.7 6.4 5.9 7.0 7.4 AUG 6.7 6.5 4.5 6.8 6.7
SEP 5.6 6.3 6.4 6.3 6.7 6.9 6.8 7.7 6.7 SEP 7.0 6.9 6.7 6.1 7.0 7.2 SEP 6.2 6.4 7.0 6.9
OCT 5.2 6.9 6.5 6.4 7.1 7.4 7.2 7.5 6.7 OCT 7.2 6.7 6.2 6.1 6.8 7.1 OCT 5.8 6.4 4.3 6.6 6.6
NOV 5.8 6.4 6.5 6.4 6.6 6.7 6.8 6.8 6.2 NOV 6.6 6.7 6.7 6.3 6.8 6.9 NOV 6.3 6.3 4.4 6.9 7.1
DEC 5.4 6.3 6.6 6.1 6.5 6.6 6.5 6.7 6.1 DEC 6.1 5.9 6.2 6.2 6.5 6.5 DEC 5.9 5.9 3.8 6.5 6.7
mean 5.9 6.7 6.6 6.5 6.8 7.1 6.9 7.3 6.8 mean 6.8 6.5 6.6 6.1 6.7 6.9 mean 6.3 6.2 4.1 6.8 6.8
std dev 0.4 0.3 0.1 0.2 0.3 0.3 0.2 0.3 0.4 std dev 0.4 0.5 0.3 0.2 0.2 0.3 std dev 0.3 0.2 0.2 0.2 0.4
max 6.5 7.1 6.7 6.9 7.5 7.7 7.2 7.7 7.5 max 7.2 7.1 7.1 6.4 7.1 7.4 max 6.7 6.5 4.5 7.4 7.4
min 5.2 6.3 6.3 6.1 6.4 6.6 6.5 6.7 6.1 min 6.1 5.5 6.2 5.9 6.4 6.5 min 5.8 5.7 3.8 6.5 6.0
25
Table 2.5 Dissolved Oxygen (mg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 10.1 10.0 10.1 10.1 10.4 10.3 9.7 9.7 9.1 9.3 JAN 11.0 10.6 10.4 9.6 9.9 8.9
FEB 10.8 10.7 10.6 10.5 10.5 10.5 10.4 10.0 9.5 10.0 FEB 12.1 11.7 11.4 11.4 11.1 10.5
MAR 8.4 9.0 8.4 8.2 8.7 8.5 8.4 7.8 7.8 8.2 MAR 11.4 11.3 11.2 9.9 9.9 8.1
APR 7.8 7.9 7.8 7.8 8.2 8.1 8.2 7.9 8.0 7.2 APR 9.3 9.0 9.0 7.1 7.8 7.6
MAY 5.5 5.9 6.2 6.1 6.4 7.4 7.6 7.4 7.0 7.2 MAY 7.5 6.7 5.8 5.5 5.9 6.6
JUN 4.9 4.9 4.9 5.0 5.2 5.6 6.3 6.7 6.7 5.0 JUN 7.0 5.7 5.5 4.5 4.9 4.3
JUL 4.2 4.6 5.6 5.3 5.6 6.3 7.1 6.4 6.3 5.2 JUL 8.7 4.2 3.5 3.5 3.7 4.6
AUG 3.9 4.0 4.2 4.3 4.9 5.7 6.9 6.6 6.1 5.2 AUG 7.3 7.3 4.7 5.1 4.3 5.1
SEP 4.0 3.8 3.8 3.6 4.2 4.7 5.8 6.0 5.9 4.6 SEP 6.1 6.0 4.6 4.4 4.3 4.0
OCT 4.4 4.4 4.7 4.9 5.0 5.9 6.0 6.4 6.2 6.2 OCT 6.6 6.7 5.2 5.3 5.0 4.4
NOV 7.7 8.2 7.6 6.9 6.4 5.7 5.7 6.0 7.1 7.6 NOV 8.8 8.0 5.7 5.7 5.6 6.3
DEC 8.4 7.9 8.3 7.0 7.5 8.0 8.1 8.5 8.3 7.7 DEC 10.2 9.8 9.5 7.4 8.5 7.2
mean 6.7 6.8 6.9 6.6 6.9 7.2 7.5 7.5 7.3 7.0 mean 8.8 8.1 7.2 6.6 6.7 6.5
std dev 2.5 2.5 2.3 2.2 2.1 1.9 1.5 1.4 1.2 1.7 std dev 2.0 2.4 2.9 2.5 2.6 2.1
max 10.8 10.7 10.6 10.5 10.5 10.5 10.4 10.0 9.5 10.0 max 12.1 11.7 11.4 11.4 11.1 10.5
min 3.9 3.8 3.8 3.6 4.2 4.7 5.7 6.0 5.9 4.6 min 6.1 4.2 3.5 3.5 3.7 4.0
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 8.0 7.8 7.5 7.2 8.3 11.6 9.1 9.2 4.3 JAN 10.7 10.8 8.7 7.3 10.3 9.9 JAN 8.9 8.6 7.0 8.7 8.9
FEB 8.1 7.9 10.0 7.5 8.7 11.0 9.5 9.5 6.8 FEB 12.0 12.2 10.6 9.8 12.0 12.2 FEB 9.7 10.5 9.7 9.8 9.8
MAR 11.6 11.3 12.2 10.6 9.9 11.8 11.0 11.8 10.6 MAR 11.7 11.7 11.7 10.5 10.4 10.8 MAR 11.1 11.5 10.7 9.8 10.5
APR 8.5 6.6 6.8 5.2 7.4 9.4 8.3 8.0 6.7 APR 7.7 7.0 5.0 4.2 8.0 7.3 APR 6.6 7.2 6.2 4.6 8.3
MAY 3.3 5.0 2.8 2.4 1.2 7.3 6.5 6.1 4.7 MAY 7.2 7.1 6.3 1.0 8.1 6.2 MAY 6.5 5.7 5.9 1.4 7.1
JUN 4.5 5.7 1.6 1.7 8.2 8.9 5.9 5.6 1.1 JUN 6.7 7.0 5.8 2.5 7.1 6.8 JUN 4.4 5.7 6.3 5.8 4.8
JUL 1.6 5.0 2.5 1.1 6.1 7.8 6.5 4.6 1.2 JUL 6.2 5.6 4.6 1.2 7.9 7.0 JUL 4.0 4.6 5.4 3.5 4.4
AUG 4.2 5.9 0.6 1.1 4.3 7.1 4.8 5.1 1.8 AUG 6.0 6.3 3.9 2.5 7.2 6.2 AUG 4.3 4.9 4.8 3.5 4.8
SEP 4.5 4.9 2.5 1.9 4.7 7.7 7.1 5.9 7.4 SEP 7.1 7.4 8.3 0.9 8.0 4.5 SEP 3.3 4.8 2.9 4.3
OCT 5.1 7.2 3.0 1.1 5.1 9.0 8.0 6.7 6.3 OCT 9.4 8.3 5.5 1.5 7.9 7.5 OCT 4.0 5.9 6.2 6.2 4.4
NOV 5.9 6.6 6.8 4.0 5.4 9.9 8.2 9.3 8.9 NOV 8.6 8.5 7.0 2.0 8.9 4.7 NOV 4.5 8.3 4.6 4.5 6.3
DEC 6.8 7.0 8.8 6.8 7.0 9.8 7.9 8.1 8.3 DEC 9.9 9.9 9.9 9.2 10.8 10.6 DEC 7.0 8.6 7.3 8.2 7.6
mean 6.0 6.7 5.4 4.2 6.4 9.3 7.7 7.5 5.7 mean 8.6 8.5 7.3 4.4 8.9 7.8 mean 6.2 7.2 6.7 5.7 6.8
std dev 2.7 1.8 3.7 3.2 2.4 1.6 1.7 2.2 3.1 std dev 2.1 2.2 2.5 3.7 1.6 2.5 std dev 2.6 2.3 1.9 2.8 2.3
max 11.6 11.3 12.2 10.6 9.9 11.8 11.0 11.8 10.6 max 12.0 12.2 11.7 10.5 12.0 12.2 max 11.1 11.5 10.7 9.8 10.5
min 1.6 4.9 0.6 1.1 1.2 7.1 4.8 4.6 1.1 min 6.0 5.6 3.9 0.9 7.1 4.5 min 3.3 4.6 4.6 1.4 4.3
26
0
1
2
3
4
5
6
7
8
9
10
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210 BBT
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
Figure 2.2 Dissolved Oxygen at the Lower Cape Fear River Program mainstem stations,
1995-2008 versus 2009.
1995-2008
2009
27
Table 2.6 Field Turbidity (NTU) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 89 72 81 60 61 23 21 18 27 36 JAN 16 21 19 12 16 26
FEB 18 17 19 12 15 9 10 7 10 11 FEB 12 11 14 14 17 32
MAR 8 9 12 16 16 11 7 16 19 10 MAR 40 38 32 16 30 4
APR 14 16 14 9 11 8 14 17 22 15 APR 26 23 21 7 12 13
MAY 7 9 8 7 9 8 6 5 8 6 MAY 13 17 18 17 20 51
JUN 13 19 9 5 5 4 3 4 6 8 JUN 9 15 13 8 9 17
JUL 14 12 10 8 10 8 5 5 3 9 JUL 6 9 10 12 9 9
AUG 26 15 17 9 8 9 7 3 7 8 AUG 7 7 8 6 11 11
SEP 37 9 8 3 4 7 8 5 7 6 SEP 8 6 10 6 8 8
OCT 19 36 14 9 9 9 6 8 9 12 OCT 18 11 11 8 12 18
NOV 59 78 82 40 51 33 16 12 6 15 NOV 8 11 11 10 21 13
DEC 18 17 22 25 20 14 10 13 25 15 DEC 56 50 47 21 33 6
mean 27 26 25 17 18 12 9 9 12 13 mean 18 18 18 11 17 17
std dev 24 24 27 17 18 8 5 5 8 8 std dev 15 13 11 5 8 13
max 89 78 82 60 61 33 21 18 27 36 max 56 50 47 21 33 51
min 7 9 8 3 4 4 3 3 3 6 min 6 6 8 6 8 4
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 4 5 4 2 6 4 5 11 10 JAN 5 5 2 1 6 7 JAN 5 1 0 3 12
FEB 4 3 3 2 6 3 5 9 15 FEB 4 5 2 1 5 5 FEB 4 2 3 3 22
MAR 6 2 1 1 7 11 5 8 8 MAR 8 5 3 4 8 9 MAR 3 6 6 7 21
APR 1 4 1 0 3 13 6 11 10 APR 3 0 0 0 8 5 APR 2 1 0 2 15
MAY 7 13 7 4 32 90 31 167 81 MAY 4 6 3 4 5 6 MAY 2 1 1 2 8
JUN 2 7 8 3 23 1 4 12 8 JUN 5 5 3 12 14 18 JUN 7 4 3 7 21
JUL 1 1 28 7 13 5 4 13 11 JUL 2 2 4 26 4 5 JUL 2 3 4 24 19
AUG 3 2 15 14 16 3 8 13 8 AUG 8 7 9 19 7 6 AUG 3 4 7 9 19
SEP 13 3 3 0 6 8 11 16 7 SEP 6 6 13 8 3 8 SEP 2 3 5 10
OCT 6 4 3 4 6 5 7 12 19 OCT 5 4 6 3 38 7 OCT 1 3 4 7 12
NOV 6 3 2 1 6 10 8 16 15 NOV 3 2 4 3 3 7 NOV 3 4 1 4 25
DEC 6 8 2 18 60 12 10 15 13 DEC 5 3 1 1 6 11 DEC 7 4 2 4 18
mean 5 5 6 5 15 14 9 25 17 mean 5 4 4 7 9 8 mean 3 3 3 6 17
std dev 3 3 8 6 16 24 7 45 20 std dev 2 2 4 8 10 4 std dev 2 2 2 6 5
max 13 13 28 18 60 90 31 167 81 max 8 7 13 26 38 18 max 7 6 7 24 25
min 1 1 1 0 3 1 4 8 7 min 2 0 0 0 3 5 min 1 1 0 2 8
28
0
5
10
15
20
25
30
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210 BBT
Fi
e
l
d
T
u
r
b
i
d
i
t
y
(
N
T
U
)
Figure 2.3 Field Turbidity at the Lower Cape Fear River Program mainstem stations,
1995-2008 versus 2009.
1995-2008
2009
29
Table 2.7 Total Suspended Solids (mg/L) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 59 30 34 25 42 16 22 24 35 42 JAN 7 8 9 10 29
FEB 12 11 11 9 10 10 18 8 8 18 FEB 5 5 8 7 24
MAR 7 8 11 17 17 14 12 35 33 20 MAR 54 46 45 27 3
APR 14 15 19 13 11 12 12 28 53 22 APR 27 29 24 12 16
MAY 6 9 9 8 15 13 14 9 19 18 MAY 9 8 13 18 86
JUN 15 17 7 9 8 11 10 11 9 21 JUN 8 9 15 10 20
JUL 18 15 12 9 16 10 8 10 8 26 JUL 7 8 7 5 9
AUG 29 16 21 11 13 15 13 8 11 21 AUG 4 2 4 5 15
SEP 47 12 17 7 10 13 19 13 20 12 SEP 7 5 7 9 20
OCT 22 25 10 7 8 8 7 8 10 21 OCT 8 7 6 10 17
NOV 45 44 35 14 34 20 11 11 6 23 NOV 3 6 6 16 9
DEC 15 15 9 13 15 14 11 10 19 16 DEC 56 57 54 32 3
mean 24 18 16 12 17 13 13 15 19 22 mean 16 16 17 13 21
std dev 17 10 10 5 11 3 5 9 14 7 std dev 19 18 16 9 22
max 59 44 35 25 42 20 22 35 53 42 max 56 57 54 32 86
min 6 8 7 7 8 8 7 8 6 12 min 3 2 4 5 3
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 2 2 1 1 5 1 2 4 4 JAN 3 3 1 1 5 3 JAN 4 1 1 1
FEB 3 2 2 1 4 1 3 5 7 FEB 2 4 1 1 2 1 FEB 3 1 1 1
MAR 3 2 1 1 6 11 6 6 4 MAR 5 3 3 2 17 6 MAR 2 2 2 4
APR 3 6 3 2 8 16 9 12 6 APR 5 2 3 2 19 5 APR 3 1 1 3
MAY 5 10 8 4 25 101 28 110 28 MAY 1 3 2 11 3 3 MAY 6 2 3 3
JUN 4 10 13 7 13 2 4 12 7 JUN 1 4 2 10 13 8 JUN 5 1 1 4
JUL 8 16 28 9 73 3 1 8 10 JUL 2 1 3 23 1 4 JUL 2 1 3 13
AUG 5 3 14 12 27 2 13 6 8 AUG 4 6 8 9 3 4 AUG 3 1 13 8
SEP 4 7 4 4 8 9 14 12 7 SEP 1 3 6 6 1 2 SEP 3 1 4
OCT 3 3 3 13 4 3 3 7 8 OCT 2 4 4 4 27 4 OCT 3 4 2 2
NOV 1 1 1 1 2 5 6 7 7 NOV 1 1 3 4 1 4 NOV 4 1 2 2
DEC 3 4 2 5 16 10 6 9 6 DEC 3 1 1 1 4 4 DEC 4 1 1 1mean467516148179mean333684mean4134
std dev 2 5 8 4 20 28 8 30 6 std dev 2 2 2 6 9 2 std dev 1 1 3 3
max 8 16 28 13 73 101 28 110 28 max 5 6 8 23 27 8 max 6 4 13 13
min 1 1 1 1 2 1 1 4 4 min 1 1 1 1 1 1 min 2 1 1 1
30
Table 2.8 Light Attenuation (k) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 5.84 5.62 5.79 5.82 6.10 3.24 3.01 2.41 3.21 3.34 JAN 2.07 3.29 2.59 3.04 3.11
FEB 2.52 2.80 2.95 2.26 2.66 1.41 1.15 1.11 0.97 2.19 FEB 1.92 2.17 2.49 2.43 2.57 4.62
MAR 2.85 2.65 3.02 3.40 3.40 2.72 2.50 2.50 3.10 1.56 MAR 4.63 4.38 4.10 3.26 3.64 3.11
APR 3.51 1.89 2.78 2.57 APR 3.11 3.17 3.06 3.13 2.95 4.14
MAY 2.83 3.09 3.19 2.57 2.59 2.55 1.73 1.23 1.72 MAY 2.51 2.46 3.20 2.82 4.34 5.76
JUN 3.32 3.83 3.62 2.78 2.76 2.46 2.13 1.74 1.47 2.10 JUN 2.55 3.79 2.55 3.50 2.93 5.86
JUL 3.40 3.53 3.27 3.03 2.47 2.04 1.58 1.02 1.00 1.83 JUL 2.77 3.24 3.36 3.28 3.49 2.77
AUG 4.30 3.72 3.91 2.79 2.40 2.36 1.27 1.21 1.86 AUG
SEP 6.30 4.29 3.68 3.42 2.66 2.64 2.03 1.89 1.94 1.69 SEP 2.34 1.84 3.63 3.87 4.13 4.31
OCT 4.96 4.74 3.96 3.68 3.43 3.00 2.29 1.71 1.14 1.69 OCT 2.35 2.36 3.26 3.20 3.30 5.85
NOV 6.63 6.04 6.17 6.04 5.60 4.54 2.89 2.34 1.70 2.27 NOV 1.69 2.88 4.03 3.96 4.69 3.63
DEC 3.32 4.18 4.22 4.62 4.16 3.71 3.05 2.98 3.04 2.61 DEC 6.00 5.77 5.72 4.67 4.97 4.88
mean 4.15 4.04 3.98 3.67 3.48 2.83 2.25 1.84 1.96 2.12 mean 2.90 3.21 3.45 3.38 3.65 4.49
std dev 1.44 1.09 1.07 1.28 1.29 0.87 0.61 0.62 0.90 0.52 std dev 1.29 1.12 0.93 0.61 0.78 1.12
max 6.63 6.04 6.17 6.04 6.10 4.54 3.05 2.98 3.21 3.34 max 6.00 5.77 5.72 4.67 4.97 5.86
min 2.52 2.65 2.95 2.26 2.40 1.41 1.15 1.02 0.97 1.56 min 1.69 1.84 2.49 2.43 2.57 2.77
median 3.46 3.83 3.68 3.40 2.76 2.68 2.29 1.82 1.70 1.98 median 2.51 3.17 3.26 3.26 3.49 4.47
31
Table 2.9 Total Nitrogen (µg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 1,920 1,460 1,660 1,400 1,620 1,960 1,260 1,470 940 600 JAN 1,350 1,580 1,340 1,360 1,360
FEB 1,430 1,290 720 1,320 1,370 940 890 490 430 510 FEB 1,380 1,570 1,400 1,600 1,600
MAR 990 930 900 1,050 1,090 1,080 950 530 770 680 MAR 1,280 1,300 1,360 970 970
APR 1,560 1,290 1,010 830 900 1,030 890 730 230 500 APR 1,190 1,290 1,220 1,230 1,230
MAY 1,320 1,430 1,400 1,300 1,050 910 410 330 100 340 MAY 1,130 1,290 1,090 1,190 1,190
JUN 1,630 1,900 1,370 1,260 1,130 1,170 1,210 430 340 300 JUN 1,750 1,860 1,910 1,660 1,660
JUL 1,190 920 850 720 700 680 530 300 600 600 JUL 2,360 2,210 1,660 1,420 1,420
AUG 1,410 1,680 1,120 1,060 1,060 960 880 550 500 600 AUG 1,810 2,000 1,920 1,860 1,860
SEP 1,370 1,050 1,100 860 900 710 860 740 860 640 SEP 1,640 1,450 1,660 1,920 1,920
OCT 1,030 960 830 1,330 700 580 190 320 100 60 OCT 1,150 1,290 910 1,120 1,120
NOV 1,340 1,220 1,300 980 1,240 960 800 590 570 410 NOV 1,920 2,260 1,580 1,240 1,240
DEC 1,240 940 1,080 1,030 1,130 1,020 990 640 560 450 DEC 1,010 1,070 840 910 910
mean 1,369 1,256 1,112 1,095 1,074 1,000 822 593 500 474 mean 1,498 1,598 1,408 1,373 1,373
std dev 246 305 265 215 252 334 297 301 264 169 std dev 385 378 340 314 314
max 1,920 1,900 1,660 1,400 1,620 1,960 1,260 1,470 940 680 max 2,360 2,260 1,920 1,920 1,920
min 990 920 720 720 700 580 190 300 100 60 min 1,010 1,070 840 910 910
median 1,355 1,255 1,090 1,055 1,075 960 885 540 530 505 median 1,365 1,510 1,380 1,300 1,300
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1,300 1,460 840 1,400 1,720 880 1,690 5,970 830 JAN 1,680 1,330 1,280 680 1,160 1,180 JAN 1,050 980 800 820
FEB 1,100 1,340 700 2,000 930 660 2,450 7,150 790 FEB 1,520 1,650 1,130 710 990 750 FEB 1,330 980 600 760
MAR 3,940 1,690 1,780 3,510 5,060 2,770 2,240 4,760 1,050 MAR 2,180 1,780 1,750 1,030 1,630 2,070 MAR 1,160 1,240 820 2,000
APR 980 1,060 630 1,300 1,180 860 1,280 7,720 270 APR 1,340 890 890 890 940 970 APR 1,090 1,260 1,100 970
MAY 980 1,120 800 620 1,080 1,240 1,420 3,840 1,650 MAY 1,300 920 1,020 950 630 560 MAY 990 840 730 3,330
JUN 1,400 1,240 1,120 1,080 2,300 830 1,890 9,710 1,220 JUN 1,550 1,220 1,210 1,100 1,290 950 JUN 1,120 1,000 1,140 650
JUL 1,500 1,240 1,820 1,300 4,940 1,010 4,940 13,800 1,380 JUL 720 720 1,530 1,700 980 470 JUL 1,180 1,150 1,730 1,140
AUG 1,640 980 1,700 1,520 2,940 1,450 1,790 9,610 1,360 AUG 1,250 1,390 1,530 1,110 750 460 AUG 1,180 1,130 1,830 1,090
SEP 1,710 1,460 1,220 1,200 1,480 1,080 2,050 14,900 1,270 SEP 1,410 1,150 680 650 550 200 SEP 1,020 1,100 1,380
OCT 1,520 910 900 1,740 1,620 970 2,710 10,200 760 OCT 930 600 540 900 1,010 400 OCT 900 780 740 710
NOV 2,300 1,790 1,010 1,980 3,110 1,900 1,710 4,600 1,400 NOV 880 410 1,190 640 710 100 NOV 980 500 700 1,090
DEC 1,500 1,500 1,100 2,250 3,240 2,070 1,850 2,780 640 DEC 1,440 730 100 100 1,420 1,640 DEC 1,040 540 810 1,040
mean 1,656 1,316 1,135 1,658 2,467 1,310 2,168 7,920 1,052 mean 1,350 1,066 1,071 872 1,005 813 mean 1,087 958 1,000 1,248
std dev 770 264 401 705 1,363 604 921 3,686 381 std dev 375 407 445 364 313 563 std dev 111 240 399 717
max 3,940 1,790 1,820 3,510 5,060 2,770 4,940 14,900 1,650 max 2,180 1,780 1,750 1,700 1,630 2,070 max 1,330 1,260 1,830 3,330
min 980 910 630 620 930 660 1,280 2,780 270 min 720 410 100 100 550 100 min 900 500 600 650
median 1,500 1,290 1,055 1,460 2,010 1,045 1,870 7,435 1,135 median 1,375 1,035 1,160 895 985 655 median 1,070 990 810 1,065
32
0
200
400
600
800
1000
1200
1400
1600
1800
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210
To
t
a
l
N
i
t
r
o
g
e
n
(
µg/
L
)
Figure 2.4 Total Nitrogen at the Lower Cape Fear River Program mainstem stations,
1995-2008 versus 2009.
1995-2008
2009
33
Table 2.10 Nitrate/Nitrite (µg/l) during 2009 at the Lower Cape Fear River stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 720 660 660 600 620 560 360 270 40 200 JAN 750 680 640 560 250
FEB 730 690 720 630 570 340 290 90 30 110 FEB 880 870 800 800 610
MAR 290 330 300 350 390 380 350 130 70 180 MAR 580 600 660 470 680
APR 560 590 510 130 400 330 290 130 30 10 APR 590 590 520 430 230
MAY 620 630 600 500 450 310 210 30 10 40 MAY 730 790 490 590 420
JUN 730 700 570 460 430 370 310 130 40 10 JUN 950 760 910 760 410
JUL 390 320 250 220 200 80 30 10 10 10 JUL 660 610 460 520 220
AUG 910 880 720 560 460 360 180 50 10 10 AUG 910 1000 820 760 270
SEP 470 450 400 360 300 310 260 140 160 40 SEP 640 750 560 520 320
OCT 330 360 430 330 300 280 190 120 10 60 OCT 650 590 410 520 270
NOV 540 620 600 380 440 460 400 390 270 210 NOV 1320 1460 880 540 180
DEC 440 340 380 330 330 320 290 240 160 150 DEC 610 570 540 510 520
mean 561 548 512 404 408 342 263 144 70 86 mean 773 773 641 582 365
std dev 180 175 152 145 112 108 96 104 79 76 std dev 205 243 165 117 157
max 910 880 720 630 620 560 400 390 270 210 max 1,320 1,460 910 800 680
min 290 320 250 130 200 80 30 10 10 10 min 580 570 410 430 180
median 550 605 540 370 415 335 290 130 35 50 median 695 715 600 530 295
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 300 460 40 800 820 180 990 5370 130 JAN 1080 630 580 180 360 380 JAN 350 380 10 220
FEB 100 540 10 1200 330 260 1450 6950 90 FEB 1120 950 630 210 490 350 FEB 630 480 10 160
MAR 1840 990 980 2710 3460 1570 1440 4160 550 MAR 1080 780 950 330 730 670 MAR 360 440 20 300
APR 80 160 30 700 480 160 580 6820 70 APR 540 190 90 90 140 170 APR 190 260 10 170
MAY 80 320 10 120 80 140 520 2740 850 MAY 800 320 220 50 230 160 MAY 290 240 30 730
JUN 100 240 20 80 10 130 990 9510 120 JUN 650 320 210 10 90 250 JUN 220 200 40 150
JUL 10 40 20 10 40 110 3740 13200 180 JUL 220 120 730 10 380 70 JUL 180 150 30 140
AUG 140 80 10 20 440 350 590 7810 160 AUG 250 190 30 110 250 60 AUG 180 230 30 190
SEP 110 60 20 100 80 80 650 14100 70 SEP 310 150 80 50 250 10 SEP 20 100 580
OCT 120 110 10 40 220 170 1710 9450 160 OCT 230 100 40 10 310 10 OCT 100 80 40 110
NOV 900 190 110 1280 2210 1000 810 3600 700 NOV 380 110 390 40 210 10 NOV 180 100 10 290
DEC 600 1100 700 1750 2540 1470 1350 2280 640 DEC 940 430 40 60 920 740 DEC 340 40 510 640mean3653581637348934681,235 7,166 310 mean 633 358 333 96 363 240 mean 253 225 67 307
std dev 510 342 309 826 1,119 526 847 3,699 274 std dev 343 273 303 94 234 241 std dev 150 138 140 208
max 1,840 1,100 980 2,710 3,460 1,570 3,740 14,100 850 max 1,120 950 950 330 920 740 max 630 480 510 730
min 10 40 10 10 10 80 520 2,280 70 min 220 100 30 10 90 10 min 20 40 10 110
median 115 215 20 410 385 175 990 6,885 160 median 595 255 215 55 280 165 median 205 215 30 205
34
Table 2.11 Ammonium (µg/l) during 2009 at the Lower Cape Fear River stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 80 40 60 70 140 60 50 20 5 10 JAN 40 180 70 50 10
FEB 50 60 60 60 90 10 10 5 5 10 FEB 5 20 30 30 50
MAR 20 5 10 40 100 40 50 5 5 20 MAR 10 10 5 20 30
APR 60 60 60 80 60 70 40 5 5 5 APR 10 20 30 40 20
MAY 100 100 90 80 60 30 10 5 5 5 MAY 130 90 140 130 60
JUN 100 100 90 100 5 60 5 5 5 5 JUN 90 220 90 80 60
JUL 90 100 70 80 130 10 20 5 5 5 JUL 20 460 90 80 10
AUG 40 50 20 20 20 10 5 5 5 5 AUG 10 50 140 130 5
SEP 70 40 40 10 10 20 5 5 5 10 SEP 90 60 100 80 10
OCT 40 30 40 30 30 20 20 20 10 10 OCT 50 90 70 50 40
NOV 80 70 80 60 130 80 100 100 90 80 NOV 20 100 50 40 50
DEC 50 40 40 60 80 100 60 50 30 60 DEC 60 60 60 40 30
mean 65 58 55 58 71 43 31 19 15 19 mean 45 113 73 64 31
std dev 25 29 25 26 46 29 28 28 24 24 std dev 39 121 40 35 20
max 100 100 90 100 140 100 100 100 90 80 max 130 460 140 130 60
min 20 5 10 10 5 10 5 5 5 5 min 5 10 5 20 5
median 65 55 60 60 70 35 20 5 5 10 median 30 75 70 50 30
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 20 60 30 10 160 60 40 10 20 JAN 20 20 20 10 30 30 JAN 10 5 5 5
FEB 30 30 5 10 100 70 20 20 40 FEB 20 10 10 20 40 50 FEB 5 10 10 10
MAR 50 5 5 5 5 220 50 80 30 MAR 70 20 20 10 50 370 MAR 30 20 20 30
APR 40 50 20 50 190 70 30 80 40 APR 5 5 10 10 10 30 APR 5 5 5 5
MAY 200 120 250 140 160 320 130 280 400 MAY 50 60 60 120 60 110 MAY 110 160 160 60
JUN 190 100 10 140 440 10 10 120 240 JUN 20 40 40 50 30 90 JUN 100 100 100 150
JUL 90 5 200 150 1710 90 70 170 190 JUL 10 30 70 5 30 80 JUL 5 40 40 150
AUG 60 40 80 200 470 130 110 120 160 AUG 50 40 70 40 30 50 AUG 20 30 30 300
SEP 30 40 20 10 420 90 30 60 150 SEP 30 20 90 90 40 20 SEP 10 20 20
OCT 40 20 5 280 660 80 20 70 100 OCT 20 10 5 50 30 30 OCT 20 20 20 110
NOV 80 20 70 70 280 140 100 90 110 NOV 20 20 40 30 20 10 NOV 30 30 30 20
DEC 320 30 20 20 100 70 30 50 20 DEC 40 10 20 20 40 40 DEC 20 20 20 20
mean 96 43 60 90 391 113 53 96 125 mean 30 24 38 38 34 76 mean 30 38 40 73
std dev 89 34 78 87 438 80 38 70 109 std dev 18 15 27 34 13 93 std dev 34 44 45 86
max 320 120 250 280 1,710 320 130 280 400 max 70 60 90 120 60 370 max 110 160 160 300
min 20 5 5 5 5 10 10 10 20 min 5 5 5 5 10 10 min 5 5 5 5
median 55 35 20 60 235 85 35 80 105 median 20 20 30 25 30 45 median 20 20 20 25
35
Table 2.12 Total Kjeldahl Nitrogen (µg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 1200 800 1000 800 1000 1400 900 1200 900 400 JAN 600 900 700 800 1100
FEB 700 600 50 700 800 600 600 400 400 400 FEB 500 700 600 800 700
MAR 700 600 600 700 700 700 600 400 700 500 MAR 700 700 700 500 800
APR 1000 700 500 700 500 700 600 600 200 500 APR 600 700 700 800 800
MAY 700 800 800 800 600 600 200 300 100 300 MAY 400 500 600 600 900
JUN 900 1200 800 800 700 800 900 300 300 300 JUN 800 1100 1000 900 900
JUL 800 600 600 500 500 600 500 300 600 600 JUL 1700 1600 1200 900 1100
AUG 500 800 400 500 600 600 700 500 500 600 AUG 900 1000 1100 1100 1000
SEP 900 600 700 500 600 400 600 600 700 600 SEP 1000 700 1100 1400 1000
OCT 700 600 400 1000 400 300 100 200 100 100 OCT 500 700 500 600 600
NOV 800 600 700 600 800 500 400 200 300 200 NOV 600 800 700 700 700
DEC 800 600 700 700 800 700 700 400 400 300 DEC 400 500 300 400 500
mean 808 708 604 692 667 658 567 450 433 400 mean 725 825 767 792 842
std dev 171 171 235 144 160 260 232 260 243 158 std dev 344 289 262 260 185
max 1,200 1,200 1,000 1,000 1,000 1,400 900 1,200 900 600 max 1,700 1,600 1,200 1,400 1,100
min 500 600 50 500 400 300 100 200 100 100 min 400 500 300 400 500
median 800 600 650 700 650 600 600 400 400 400 median 600 700 700 800 850
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 1000 1000 800 600 900 700 700 600 700 JAN 600 700 700 500 800 800 JAN 700 600 800 600
FEB 1000 800 700 800 600 400 1000 200 700 FEB 400 700 500 500 500 400 FEB 700 500 600 600
MAR 2100 700 800 800 1600 1200 800 600 500 MAR 1100 1000 800 700 900 1400 MAR 800 800 800 1700
APR 900 900 600 600 700 700 700 900 200 APR 800 700 800 800 800 800 APR 900 1000 1100 800
MAY 900 800 800 500 1000 1100 900 1100 800 MAY 500 600 800 900 400 400 MAY 700 600 700 2600
JUN 1300 1000 1100 1000 2300 700 900 200 1100 JUN 900 900 1000 1100 1200 700 JUN 900 800 1100 500
JUL 1500 1200 1800 1300 4900 900 1200 600 1200 JUL 500 600 800 1700 600 400 JUL 1000 1000 1700 1000
AUG 1500 900 1700 1500 2500 1100 1200 1800 1200 AUG 1000 1200 1500 1000 500 400 AUG 1000 900 1800 900
SEP 1600 1400 1200 1100 1400 1000 1400 800 1200 SEP 1100 1000 600 600 300 200 SEP 1000 1000 800
OCT 1400 800 900 1700 1400 800 1000 800 600 OCT 700 500 500 900 700 400 OCT 800 700 700 600
NOV 1400 1600 900 700 900 900 900 1000 700 NOV 500 300 800 600 500 100 NOV 800 400 700 800
DEC 900 400 400 500 700 600 500 500 100 DEC 500 300 100 100 500 900 DEC 700 500 300 400
mean 1,292 958 975 925 1,575 842 933 758 750 mean 717 708 742 783 642 575 mean 833 733 936 942
std dev 352 307 400 383 1,163 225 239 413 359 std dev 244 266 317 378 240 344 std dev 118 205 437 594
max 2,100 1,600 1,800 1,700 4,900 1,200 1,400 1,800 1,200 max 1,100 1,200 1,500 1,700 1,200 1,400 max 1,000 1,000 1,800 2,600
min 900 400 400 500 600 400 500 200 100 min 400 300 100 100 300 100 min 700 400 300 400
median 1,350 900 850 800 1,200 850 900 700 700 median 650 700 800 750 550 400 median 800 750 800 800
36
Table 2.13 Total Phosphorus (µg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 270 180 190 150 180 80 70 40 70 70 JAN 90 180 90 90 120
FEB 90 90 140 80 70 50 70 20 20 40 FEB 90 90 100 100 100
MAR 70 80 90 100 110 70 60 50 80 40 MAR 170 180 160 120 60
APR 110 120 120 90 80 80 60 60 80 70 APR 150 130 120 100 80
MAY 110 120 130 100 90 90 50 30 20 30 MAY 120 110 130 150 230
JUN 140 130 90 100 70 70 60 30 40 10 JUN 170 210 170 140 130
JUL 150 110 110 90 100 120 80 40 30 50 JUL 200 200 140 140 120
AUG 210 170 140 110 110 110 80 40 40 50 AUG 170 170 150 180 130
SEP 260 150 140 110 110 110 110 90 70 50 SEP 170 150 180 180 130
OCT 130 120 140 90 100 70 60 50 40 50 OCT 150 150 120 140 120
NOV 180 170 170 130 140 100 70 70 50 40 NOV 200 260 170 130 60
DEC 80 80 80 90 70 60 60 40 50 40 DEC 170 140 130 120 80
mean 150 127 128 103 103 84 69 47 49 45 mean 154 164 138 133 133
std dev 64 33 31 19 31 21 15 18 21 16 std dev 35 44 27 28 28
max 270 180 190 150 180 120 110 90 80 70 max 200 260 180 180 180
min 70 80 80 80 70 50 50 20 20 10 min 90 90 90 90 90
median 135 120 135 100 100 80 65 40 45 45 median 170 160 135 135 120
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 110 90 110 110 160 30 210 530 100 JAN 50 30 110 20 80 70 JAN 70 30 10 30
FEB 70 60 60 90 160 20 230 740 70 FEB 30 20 60 10 40 50 FEB 40 30 10 30
MAR 140 50 40 60 100 60 90 210 50 MAR 90 40 60 30 60 70 MAR 60 40 50 30
APR 80 110 110 150 190 70 170 820 90 APR 70 30 160 50 110 140 APR 60 40 10 30
MAY 190 180 240 270 580 300 310 750 300 MAY 110 260 310 110 100 170 MAY 80 100 30 40
JUN 160 170 270 330 360 40 300 1,180 220 JUN 80 60 290 130 100 100 JUN 60 100 10 50
JUL 130 130 480 370 2,950 70 560 1,690 160 JUL 180 100 460 220 110 170 JUL 80 130 50 70
AUG 200 150 370 650 840 90 380 1,280 260 AUG 200 100 530 130 90 180 AUG 120 120 100 50
SEP 240 160 150 260 350 100 310 1,990 180 SEP 140 70 250 100 80 200 SEP 90 120 60
OCT 160 140 80 540 250 100 500 1,240 170 OCT 120 60 120 70 190 190 OCT 80 100 390 20
NOV 200 60 60 70 140 60 130 350 70 NOV 120 40 300 70 80 90 NOV 70 80 70 30
DEC 210 50 40 80 140 50 100 200 30 DEC 50 10 50 10 40 50 DEC 80 40 10 10
mean 158 113 168 248 518 83 274 915 142 mean 103 68 225 79 90 123 mean 74 78 67 38
std dev 51 47 137 187 762 70 144 548 83 std dev 50 64 153 60 38 55 std dev 19 37 106 16
max 240 180 480 650 2,950 300 560 1,990 300 max 200 260 530 220 190 200 max 120 130 390 70
min 70 50 40 60 100 20 90 200 30 min 30 10 50 10 40 50 min 40 30 10 10
median 160 120 110 205 220 65 265 785 130 median 100 50 205 70 85 120 median 75 90 30 30
37
0
20
40
60
80
100
120
140
160
180
200
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210
To
t
a
l
P
h
o
s
p
h
o
r
u
s
(
µg/
L
)
Figure 2.5 Total Phosphorus at the Lower Cape Fear River program manistem stations,
1995-2008 versus 2009.
1995-2008
2009
38
Table 2.14 Orthophosphate (µg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 80 70 60 40 40 30 10 10 10 10 JAN 40 50 40 30 30 30
FEB 30 30 30 30 10 10 10 0 0 0 FEB 40 40 30 30 30 20
MAR 10 20 20 23 30 30 20 10 10 10 MAR 20 20 30 20 20 20
APR 30 30 30 30 30 30 20 10 0 0 APR 30 30 30 10 20 10
MAY 60 50 50 50 40 30 10 0 0 0 MAY 50 50 50 50 50 40
JUN 60 60 60 40 40 30 20 10 0 10 JUN 70 100 90 40 70 40
JUL 50 40 30 30 40 20 10 20 10 10 JUL 70 90 70 60 80 40
AUG 110 60 50 70 60 50 20 10 10 10 AUG 110 130 110 100 110 60
SEP 100 60 50 60 40 40 30 30 20 20 SEP 50 160 90 70 100 40
OCT 40 50 50 30 40 30 20 20 10 20 OCT 90 100 60 50 70 40
NOV 30 30 30 40 50 40 40 40 30 30 NOV 150 160 100 70 60 30
DEC 40 40 30 40 40 40 30 30 20 20 DEC 40 30 30 20 40 40
mean 53 45 41 40 38 32 20 16 10 12 mean 63 80 61 46 57 34
std dev 30 16 14 14 12 10 10 12 10 9 std dev 37 51 30 26 30 13
max 110 70 60 70 60 50 40 40 30 30 max 150 160 110 100 110 60
min 10 20 20 23 10 10 10 0 0 0 min 20 20 30 10 20 10
median 45 45 40 40 40 30 20 10 10 10 median 50 70 55 45 55 40
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 60 20 20 50 60 0 130 330 10 JAN 10 10 60 0 20 20 JAN 40 10 10 10
FEB 30 10 10 40 30 20 160 610 10 FEB 10 0 40 0 10 10 FEB 10 0 0 10
MAR 70 0 0 20 20 0 20 100 10 MAR 20 0 20 0 10 10 MAR 10 0 0 30
APR 20 20 20 80 40 0 60 550 20 APR 10 0 70 0 20 30 APR 10 10 10 0
MAY 100 50 50 90 70 10 80 260 80 MAY 40 140 110 20 30 50 MAY 40 30 10 0
JUN 110 50 40 70 20 10 170 1,000 70 JUN 50 30 160 10 30 50 JUN 40 30 10 0
JUL 50 60 20 60 80 20 340 1,380 50 JUL 50 40 340 20 30 60 JUL 50 30 20 0
AUG 140 60 80 260 280 20 200 1,120 80 AUG 80 50 290 30 40 90 AUG 50 74 30 10
SEP 190 50 40 150 110 20 20 1,720 40 SEP 50 20 130 20 40 140 SEP 40 40 20
OCT 110 30 30 70 50 20 160 1,030 40 OCT 60 50 10 10 40 80 OCT 40 30 320 0
NOV 160 30 30 40 60 20 80 300 10 NOV 50 20 180 10 40 90 NOV 30 30 40 10
DEC 20 30 20 50 40 10 50 20 60 DEC 20 10 30 0 20 20 DEC 60 30 10 0
mean 88 34 30 82 72 13 123 702 40 mean 38 31 120 10 28 54 mean 35 26 42 8
std dev 56 20 21 65 71 9 92 541 28 std dev 23 39 107 10 11 40 std dev 17 20 93 10
max 190 60 80 260 280 20 340 1,720 80 max 80 140 340 30 40 140 max 60 74 320 30
min 20 0 0 20 20 0 20 20 10 min 10 0 10 0 10 10 min 10 0 0 0
median 85 30 25 65 55 15 105 580 40 median 45 20 90 10 30 50 median 40 30 10 5
39
Table 2.15 Chlorophyll a (µg/l) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 3 2 3 3 4 4 4 5 9 6 JAN 3 2 2 1 1 2
FEB 5 6 12 6 7 10 9 6 5 10 FEB 10 7 5 4 4 3
MAR 11 16 11 8 8 6 3 6 6 5 MAR 16 19 20 12 13 1
APR 3 3 4 3 4 5 6 7 8 6 APR 7 7 8 2 4 5
MAY 3 3 15 7 7 31 12 6 5 10 MAY 6 4 3 2 2 7
JUN 1 1 1 2 1 3 2 3 2 6 JUN 5 3 3 1 2 2
JUL 5 20 25 24 18 30 21 13 8 7 JUL 61 11 2 2 6 10
AUG 6 5 10 10 12 20 26 10 8 8 AUG 22 15 10 11 7 4
SEP 3 2 4 3 4 7 19 13 9 5 SEP 5 5 2 2 1 2
OCT 2 3 3 5 3 7 3 5 6 5 OCT 6 4 1 1 1 2
NOV 4 4 3 2 2 2 2 3 3 3 NOV 10 6 5 4 5 2
DEC 2 2 2 1 1 1 2 3 4 2 DEC 4 3 3 1 2 0
mean 4 6 8 6 6 10 9 7 6 6 mean 13 7 5 4 4 3
std dev 3 6 7 6 5 10 8 3 2 2 std dev 15 5 5 4 3 3
max 11 20 25 24 18 31 26 13 9 10 max 61 19 20 12 13 10
min 1 1 1 1 1 1 2 3 2 2 min 3 2 1 1 1 0
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 2 2 2 4 5 1 1 1 1 JAN 1 1 1 1 1 1 JAN 1 0 0 1
FEB 2 1 2 3 6 1 6 4 2 FEB 1 1 1 1 1 1 FEB 1 1 0 1
MAR 3 3 2 3 2 2 2 1 1 MAR 2 1 3 4 2 2 MAR 1 1 1 3
APR 6 4 4 3 10 2 2 8 2 APR 1 1 2 4 2 2 APR 1 1 4 6
MAY 2 4 7 5 23 35 5 10 3 MAY 0 0 1 2 0 1 MAY 2 1 1 3
JUN 8 3 13 42 16 1 1 2 1 JUN 0 0 0 1 1 1 JUN 1 1 1 1
JUL 11 1 60 17 438 1 2 1 7 JUL 1 1 1 60 5 2 JUL 2 2 2 7
AUG 7 4 19 11 23 4 3 4 1 AUG 1 1 3 3 11 2 AUG 2 2 28 3
SEP 4 2 3 5 5 11 2 1 1 SEP 1 2 2 4 1 2 SEP 1 1 2
OCT 1 1 3 11 6 1 1 1 0 OCT 1 0 1 2 2 1 OCT 0 1 3 1
NOV 1 1 1 3 2 3 1 1 0 NOV 1 0 1 2 1 1 NOV 0 0 4 4
DEC 1 3 6 5 6 2 1 1 1 DEC 1 1 1 1 1 1 DEC 0 0 0 0
mean 4 2 10 9 45 5 2 3 2 mean 1 1 1 7 2 1 mean 1 1 4 3
std dev 3 1 16 11 119 9 2 3 2 std dev 0 1 1 16 3 1 std dev 1 1 8 2
max 11 4 60 42 438 35 6 10 7 max 2 2 3 60 11 2 max 2 2 28 7
min 1 1 1 3 2 1 1 1 0 min 0 0 0 1 0 1 min 0 0 0 0
40
0
2
4
6
8
10
12
14
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210 BBT
Ch
l
o
r
o
p
h
y
l
l
a
(µg/
L
)
Figure 2.6 Chlorophyll a at the Lower Cape Fear River program mainstem stations, 1995-
2008 versus 2009.
1995-2008
2009
41
Table 2.16 Biochemical Oxygen Demand (mg/l) during 2009 at the Lower Cape Fear River Program stations.
5-Day Biochemical Oxygen Demand
month NC11 AC ANC SAR GS N403 ROC BC117 NCF117 B210 LVC2 BBT
JAN 0.9 8.3 0.9 1.5 1.0 0.9 0.9 0.8 0.6 0.5 1.1 2.4
FEB 0.2 0.3 2.1 1.5 1.7 1.1 1.3 1.6 1.7 1.8 1.5 0.0
MAR 1.5 1.6 1.5 1.2 1.9 1.7
APR 1.7 1.4 3.1 2.0 1.9 1.7 2.2 2.9 1.2
MAY 1.9 1.5 3.4 2.8 3.0 3.7 2.4 5.6 3.0 2.5 4.2 1.5
JUN 1.5 2.7 1.7 1.9 1.8 1.4
JUL 6.9 3.4 3.0 1.0 4.7 3.0 1.5 1.1 1.2 1.8 3.5 2.3
AUG 1.8 1.8 1.7 1.8 1.4 1.7
SEP 1.3 1.0 1.4 2.0 1.5 1.6 1.5 1.5 1.2 1.4 1.5 0.9
OCT 1.0 1.8 1.2 1.0 1.0 1.2 1.1 1.4 0.8 1.1 0.9 1.2
NOV 1.7 1.2 1.1 0.8 1.3 2.0
DEC 2.2 2.1 1.1 1.3 1.4 1.8 1.6 1.6 1.3 1.1 1.3 2.0
median 1.7 1.8 1.5 1.5 1.5 1.6 1.5 1.6 1.3 1.6 1.5 1.5
mean 1.9 2.3 2.0 1.6 2.0 1.8 1.6 2.0 1.4 1.5 1.9 1.5
stdev 1.7 2.2 1.0 0.6 1.2 0.9 0.5 1.5 0.7 0.6 1.1 0.7
max 6.9 8.3 3.4 2.8 4.7 3.7 2.4 5.6 3.0 2.5 4.2 2.4
min 0.2 0.3 0.9 1.0 1.0 0.9 0.9 0.8 0.6 0.5 0.9 0.0
20-Day Biochemical Oxygen Demand
month NC11 AC ANC SAR GS N403 ROC BC117 NCF117 B210 LVC2 BBT
JAN 2.9 16.0 3.1 4.0 3.2 2.6 2.8 2.6 2.5 1.7 3.1 5.6
FEB 2.7 2.7 4.7 4.0 4.1 2.6 3.4 2.0 3.8 3.5 3.8 2.4
MAR 4.1 3.8 3.2 2.5 4.2 3.0
APR 4.1 3.7 6.6 5.4 4.8 4.2 5.7 7.2 3.2
MAY 4.7 3.8 8.1 6.7 7.2 8.1 6.1 11.6 6.6 5.3 9.4 4.3
JUN 3.4 7.3 4.5 3.7 4.4 3.6
JUL 10.6 8.4 7.5 3.1 8.2 8.3 4.5 3.2 2.8 3.1 7.4 4.3
AUG 4.2 4.3 3.1 2.6 4.2 4.4
SEP 3.2 2.8 4.0 5.6 3.6 4.6 4.5 3.7 3.2 3.2 3.4 3.3
OCT 2.7 5.2 3.4 3.0 2.7 3.6 3.2 3.6 3.3 3.6 3.7 3.2
NOV 3.5 3.3 3.1 2.0 3.7 5.6
DEC 4.7 4.6 3.1 3.3 3.5 3.9 3.8 3.7 3.5 2.6 2.9 4.3
median 3.5 4.3 4.1 4.0 3.6 3.9 4.2 3.6 3.3 3.2 3.8 4.3
mean 4.2 5.6 5.0 4.3 4.5 4.5 4.2 4.5 3.6 3.1 4.6 4.0
stdev 2.2 3.9 1.9 1.3 1.9 2.2 1.1 3.0 1.2 1.0 2.1 1.0
max 10.6 16.0 8.1 6.7 8.2 8.3 6.1 11.6 6.6 5.3 9.4 5.6
min 2.7 2.7 3.1 3.0 2.7 2.5 2.8 2.0 2.5 1.7 2.9 2.4
42
Table 2.17 Fecal Coliform Bacteria (cfu/100 ml) during 2009 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP IC NCF6
JAN 519 149 149 176 108 51 22 8 8 2 JAN 40 55 29 64 164
FEB 11 11 22 8 11 2 4 2 4 2 FEB 29 11 4 8 19
MAR 28 10 37 82 46 10 10 10 10 10 MAR 84 27 27 43 33
APR 64 64 19 10 37 5 2 12 8 15 APR 10 28 10 10 10
MAY 10 32 64 23 10 5 3 3 3 3 MAY 5 3 28 28 110
JUN 50 23 23 19 5 10 5 5 5 5 JUN 5 10 10 50 64
JUL 118 330 163 1,350 228 10 10 32 10 5 JUL 135 46 14 3 64
AUG 17 11 35 28 38 9 1 2 6 2 AUG 6 11 33 35 31
SEP 37 46 91 91 73 64 19 28 19 19 SEP 64 37 55 37 55
OCT 127 145 82 10 10 19 10 10 10 19 OCT 37 19 28 46 37
NOV 290 330 455 82 127 100 118 19 10 28 NOV 19 46 37 55 226
DEC 19 181 154 73 46 37 37 10 10 55 DEC 199 352 260 154 55
mean 108 111 108 163 62 27 20 12 9 14 mean 53 54 45 44 72
std dev 146 113 117 361 63 29 31 9 4 15 std dev 58 91 66 38 62
max 519 330 455 1,350 228 100 118 32 19 55 max 199 352 260 154 226
min 10 10 19 8 5 2 1 2 3 2 min 5 3 4 3 10
Geomean 50 57 68 47 35 15 9 8 8 8 Geomean 27 26 25 30 52
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2 SC-CH
JAN 46 591 55 73 470 96 130 100 210 JAN 136 58 73 40 390 310 JAN 65 104 37 188 172
FEB 17 38 15 8 110 40 114 118 1,200 FEB 22 19 26 40 73 186 FEB 26 50 17 17 82
MAR 100 64 19 33 46 41 77 37 91 MAR 1,140 257 17 40 28 82 MAR 51 28 19 28 73
APR 37 28 14 37 37 228 64 195 115 APR 46 28 28 14 91 250 APR 145 64 28 55 109
MAY 120 450 195 182 546 3,500 319 10,000 12,000 MAY 46 46 37 140 37 100 MAY 91 10 86 41 32
JUN 108 144 192 88 204 109 410 1,364 208 JUN 41 14 19 160 145 320 JUN 32 32 23 37 28
JUL 64 91 1,546 208 290 830 55 530 637 JUL 19 10 55 455 280 109 JUL 82 118 46 20,000 109
AUG 58 52 116 66 6,000 35 82 1,000 328 AUG 46 40 100 11,200 400 182 AUG 88 74 284 600 27
SEP 728 728 118 181 3,700 364 11,000 1,546 637 SEP 127 19 46 154 230 46 SEP 181 64 127 10
OCT 64 172 118 181 819 37 440 136 520 OCT 1,455 82 127 190 12,000 820 OCT 64 19 55 64 82
NOV 154 310 46 28 580 290 360 410 637 NOV 109 55 136 220 637 280 NOV 127 172 109 230 145
DEC 55 380 200 586 910 350 270 240 685 DEC 330 91 118 37 300 424 DEC 136 109 73 334 91
mean 129 254 220 139 1,143 493 1,110 1,306 1,439 mean 293 60 65 1,058 1,218 259 mean 91 70 71 1,810 80
std dev 184 227 406 151 1,744 933 2,985 2,667 3,198 std dev 461 64 42 3,060 3,256 201 std dev 46 46 73 5,487 48
max 728 728 1,546 586 6,000 3,500 11,000 10,000 12,000 max 1,455 257 136 11,200 12,000 820 max 181 172 284 20,000 172
min 17 28 14 8 37 35 55 37 91 min 19 10 17 14 28 46 min 26 10 17 17 10
Geomean 79 154 87 81 417 169 229 391 492 Geomean 105 40 51 130 231 197 Geomean 78 54 49 140 62
43
0
10
20
30
40
50
60
70
80
90
NC11 AC DP IC NAV HB BRR M61 M54 M42 M35 M23 M18 NCF117 NCF6 B210
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
/
1
0
0
m
L
)
Figure 2.7 Fecal Coliform Bacteria at the Lower Cape Fear River program mainstem
stations, 1996-2008 versus 2009 using geometric mean.
1995-2008
2009
44
3.0 Water Quality Evaluation by Subbasin in the Lower Cape Fear
River System
Matthew R. McIver, Michael A. Mallin, and James F. Merritt
Aquatic Ecology Laboratory
Center for Marine Science University of North Carolina Wilmington
3.0 Water Quality Evaluation by Subbasin
This section details an evaluation of water quality within each subbasin for dissolved
oxygen, turbidity, chlorophyll a, fecal coliform bacteria, nitrate+nitrite and total
phosphorus at the LCFRP sampling sites. Monthly data from January to December 2009 are used in these comparisons.
3.1 Introduction
The NC Division of Water Quality prepares a basinwide water quality plan for each of the
seventeen major river basins in the state every five years (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan October 2005). The basinwide approach is a non-
regulatory watershed based approach to restoring and protecting the quality of North
Carolina’s surface waters. The first basinwide plan for the Cape Fear River was
completed in 1996 and five-year interval updates have been completed in 2000 and
2005.
The goals of the basinwide program are to:
-Identify water quality problems and restore full use to impaired waters.
-Identify and protect high value resource waters.
-Protect unimpaired waters while allowing for reasonable economic growth.
DWQ accomplishes these goals through the following objectives:
-Collaborate with other agencies to develop appropriate management strategies. -Assure equitable distribution of waste assimilative capacity.
-Better evaluate cumulative effects of pollution.
-Improve public awareness and involvement.
The US Geological Survey (USGS) identifies 6 major hydrological areas in the Cape
Fear River Basin. Each of these hydrologic areas is further divided into subbasins by DWQ. There are 24 subbasins within the Cape Fear River basin, each denoted by six
digit numbers, 03-06-01 to 03-06-24 (NCDENR-DWQ, October 2005).
All surface waters in the state are assigned a primary classification that is appropriate to
45
the best uses of that water. North Carolina’s Water Quality Standards Program adopted
classifications and water quality standards for all the state’s river basins by 1963. The program remains consistent with the Federal Clean Water Act and its amendments.
DWQ assesses ecosystem health and human health risk through the use of five use
support categories: aquatic life, recreation, fish consumption, water supply and shellfish
harvesting. These categories are tied to the uses associated with the primary
classifications applied to NC rivers and streams. Waters are supporting if data and
information used to assign a use support rating meet the criteria for that use category. If
these criteria are not met then the waters are Impaired. Waters with inconclusive data
and information are Not Rated. Waters with insufficient data or information are rated No
Data. Because of state wide fish consumption advisories for several fishes, all waters in the basin are impaired on an evaluated basis.
For ambient water quality monitoring criteria DWQ uses water quality data collected by
both their own monitoring system as well as several NPDES discharger coalitions
including the Lower Cape Fear River Program. The parameters used to assess water
quality in the aquatic life category include dissolved oxygen (DO), pH, chlorophyll a and
turbidity as well as benthos and fish data. DWQ rates use support based on whether the
NC State Water Quality Standard is exceeded as listed below:
Numerical standard exceeded in < 10% of samples = Supporting
Numerical standard exceeded in > 10% of samples = Impaired
Less than 10 samples collected = Not Rated
DO and pH standard exceeded in swamp streams = Not Rated
*Some of the NC State Water Quality standards are written with more specific criteria
and the reader should refer to http://h2o.enr.state.nc.us/csu/index.htm for complete
details about the use of the standards.
3.2 Methods
The UNCW Aquatic Ecology Laboratory (AEL) has developed an evaluation system that
incorporates some of the guidelines used by DWQ and utilizes data collected by the
Lower Cape Fear River Program. This approach determines a water quality “rating” for the parameters dissolved oxygen, chlorophyll a, fecal coliform bacteria, field turbidity and
the nutrient species nitrate-nitrite (referred to as nitrate) and total phosphorus. For
dissolved oxygen, chlorophyll a, and fecal coliform bacteria we compare LCFRP data to
the N.C. State Water Quality Standards (http://h2o.enr.state.nc.us/csu/index.htm). Fecal
coliform bacteria data is analyzed considering human contact standards, not shellfishing
standards.
The NC DWQ does not have surface water quality standards for nitrate and total
phosphorus. The AEL water quality standard is based on levels noted to be problematic
in the scientific literature and our own published research. Based on data from four years of nutrient addition bioassay experiments using water from the Black and Northeast Cape
46
Fear Rivers, Colly Creek and Great Coharie Creek, the UNCW-AEL considers total
phophorus levels of 500 µg/L or greater potentially harmful to water quality in all the waters of the Cape Fear River watershed. Nitrate levels of 200 µg/L, 500 µg/L and 1,000
µg/L in small streams, mainstem blackwater stations (NCF117, NCF6, B210) and
mainstem Cape Fear River stations, respectively, are considered harmful to water
quality. These nutrient levels may lead to algal blooms, high bacteria levels and high
biochemical oxygen demand (BOD) in blackwater streams (Mallin et al., 2001; 2002;
2004). Water quality status for nutrient species at the mainstem Cape Fear River
stations was evaluated with a higher standard for nutrients because its waters are quite
different (greater discharge and turbidity concentrations) than the blackwater areas and
are able to better assimilate higher nutrient levels.
AEL rates use support based on whether the NC State Water Quality Standard is
exceeded as listed below:
Good = Standard is exceeded in 0 or 1 of 12 measurements (<10%)
Fair = Standard is exceeded in 2 or 3 of 12 measurements (11-25%)
Poor = Standard is exceeded in 4-12 out of 12 measurements (>25%)
The 36 stations monitored by the LCFRP by subbasin:
03-06-16
Subbasin # LCFRP Stations
BRN, HAM, NC11
03-06-17 LVC2, AC, DP, IC, NAV, HB, BRR,
M61, M54, M42, M35, M23, M18, SPD
03-06-18 SR
03-06-19 6RC, LCO, GCO
03-06-20 COL, B210, BBT
03-06-21 N403
03-06-22 SAR, GS, PB, LRC, ROC
03-06-23 ANC, BC117, BCRR, NCF6, NCF117, SC-CH
Each subbasin is addressed separately with a description and map showing the LCFRP
stations. This will be followed by a summary of the information published in the October
2005 Cape Fear River Basinwide Water Quality Plan and water quality status discussion
using the UNCW-AEL approach for the 2009 LCFRP data.
47
3.3 Cape Fear River Subbasin 03-06-16
Location: Cape Fear River upstream and downstream of Elizabethtown
Counties: Bladen, Columbus, Cumberland, Pender
Water bodies: Cape Fear River Municipalities: Elizabethtown, Dublin, White Lake, East Arcadia, Tar Heel NPDES Dischargers: 7 @ 13.7 million gallons per day Concentrated Swine Operations: 50
LCFRP monitoring stations (DWQ #):
BRN (B8340050), HAM (B8340200), NC11 (B8360000)
NC DWQ monitoring stations (DWQ #):
Six ambient monitoring stations Subbasin 03-06-16 includes the Cape Fear River
and many streams that drain coastal plain wetlands and bay lakes. Most of the watershed is forested with some agriculture
pres
48
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 101.5 freshwater miles Supporting 115.1 freshwater miles
Not Rated 40.1 freshwater miles Not Rated 4.8 freshwater miles
Not Rated 1,593.2 freshwater acres No Data 153.1 freshwater miles
No Data 131.4 freshwater miles No Data 2,510.8 freshwater acres
No Data 917.6 freshwater acres
*Brown’s Creek, rated as impaired in the 2000 CFRBWQP, was upgraded in the 2005
plan (NCDENR DWQ CFRWQBP, July 2000 and NCDENR DWQ CFRWQBP, October 2005).
Data collection: NC11 since June 1995, BRN & HAM since February 1996 Sampling relevance: Represents water entering the Lower Cape Fear River watershed
from the middle basin (NC11). There are also concentrated animal operations within the
area (BRN and HAM).
UNCW Aquatic Ecology Laboratory Evaluation
BRN - representative of small tributaries. NC11 – Main stem of the Cape Fear River
has a deep channel, is freshwater with minor tidal influence.
Dissolved Oxygen ratings for BRN and NC11 were both good. At HAM the rating was
fair, with values exceeding the NC State standard 17% of the time (Table 3.3.1).
All sites within this subbasin had a good rating for chlorophyll a concentrations (Table 3.3.1). The North Carolina State standard for chlorophyll a, 40 µg/L, was exceeded only once which was at NC11 in July 2010. We do note that blue-green algal blooms occurred
49
in the NC11 area late summer through fall 2009 (see Chapter 2).
For fecal coliform bacteria concentrations NC11 had a good rating (Table 3.3.1). BRN
and HAM received poor ratings exceeding the standard 58% and 50% of the time,
respectively.
For field turbidity all stations were rated good (Table 3.3.1). The NC State Standard of 50
NTU was exceeded once at NC11 in December.
For nitrate BRN and HAM received a poor rating exceeding the standard 83% and 42%
of the time, respectively (Table, 3.3.1, Figure 3.3.1). A good rating was found at NC11 for both nutrient species and for total phosphorus at BRN and HAM.
Table 3.3.1 UNCW AEL 2009 evaluation for subbasin 03-06-16
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
BRN G G P G P G
HAM F G P G P G
NC11 G G G G G G
Figure 3.3.1 Nitrate concentrations at the LCFRP stations BRN and HAM for 2009. The
dashed line represents the AEL standard for nitrate, 200 ug/L.
0
100
200
300
400
500
600
700
800
900
1000
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
BRN
HAM
50
51
52
3.4 Cape Fear River Subbasin 03-06-17
Location: Cape Fear River near Riegelwood, downstream to estuarine area
near Southport
Counties: Columbus, Pender, Brunswick, New Hanover
Waterbodies: Cape Fear River and Estuary
Municipalities: Wilmington, Southport NPDES Dischargers: 41 @ 99.9 million gallons per day Concentrated Swine Operations: 7
LCFRP monitoring stations (DWQ #):
LVC2 (B8445000), AC (B8450000), DP (B8460000), IC (B9030000), NAV
(B9050000), HB (B9050100), BRR (B9790000), M61 (B9750000), M54
(B9795000), M42 (B9845100), M35 (B9850100), M23 (B9910000), M18
(B9921000), SPD (B9980000)
DWQ monitoring stations:
53
Subbason 03-06-17 includes the mainstem of the Cape Fear River, the Cape Fear River
Estuary and many streams that drain the areas west of the River. Most of the watershed is forested with some urban areas including Wilmington and Southport.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 14,125.4 saltwater acres Supporting 21,092.3 saltwater acres Not Rated 2.0 saltwater acres Impaired 96.6 saltwater acres Impaired 6,457.0 saltwater acres Supporting 44.1 freshwater miles
Supporting 75.4 freshwater miles Not Rated 5.6 coast miles
Not Rated 22.3 freshwater miles Impaired 4.7 coast miles
Not Rated 406.9 freshwater acres No Data 2,254.6 saltwater acres No Data 2,859.2 saltwater acres No Data 269.1 freshwater miles No Data 215.4 freshwater miles No Data 1,251.5 freshwater acres
No Data 844.5 freshwater acres No Data 12.5 coast miles
No Data 22.8 coast miles
Data collection: Most stations since 1995, all sampled since 1998
Sampling relevance: Highly important estuary for fisheries productivity. Also receives
point source discharge and non-point source pollution.
UNCW Aquatic Ecology Laboratory Evaluation
AC – representative of riverine system HB- upper estuary, upstream of
channel Wilmington
54
M35 – represents wide estuary
Sites given a good rating for dissolved oxygen include AC, DP, IC, NAV, M42, M35, M23,
M18 and SPD (Table 3.4.1). Sites having a fair rating for dissolved oxygen, with the
percentage of samples not meeting the standard shown in parentheses, are M61 (33%)
and M54 (17%) (Figure 3.4.1). LVC2, HB and BRR were rated poor with samples below
the standard 33%, 42% and 33% of the time, respectively (Figure 3.4.2).
All sites within this subbasin had a good rating in terms of chlorophyll a concentrations
(Table 3.4.1). None of the sampled locations exceeded the 40 µg/L North Carolina State
standard on any sample occasion during 2009.
Eleven of the fourteen sites within this subbasin had a good rating for fecal coliform
bacteria concentrations (Table 3.4.1). NAV and HB both had a fair rating with 17% of
samples exceeding the state human contact standard of 200 cfu/100 mL. LVC2 had a
poor rating with 33% of samples exceeding the standard.
Nine of the fourteen sites within this subbasin had a good rating for field turbidity (Table
3.4.1). Five stations were rated fair including NAV, HB, BRR, M61 and M54 with 17%,
25%, 17%, 17% and 17% of samples exceeding the NC state standard for brackish
waters of 25 NTU, respectively.
All sites in this subbasin rated good for nitrate except LVC2 which was rated poor for
nitrate, exceeding the UNCW-AEL recommended standard (200 mg/L for stream
stations) 50% of the time (Table 3.4.1). All stations rated good for total phosphorus.
55
Table 3.4.1 UNCW AEL 2009 evaluation for subbasin 03-06-17
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
LVC2 P G P G P G
AC G G G G G G
DP G G G G G G
IC G G G G G G
NAV G G F F G G
HB P G F F G G
BRR P G G F G G
M61 F G G F G G
M54 F G G F G G
M42 G G G G G G
M35 G G G G G G
M23 G G G G G G
M18 G G G G G G
SPD G G G G G G
56
Figure 3.4.1 Dissolved oxygen concentrations at M61 and M54, rated fair for 2009. The dashed line shows the NC State Standard of 5.0 mg/L.
0
1
2
3
4
5
6
7
8
9
10
11
12
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
M54
M61
Figure 3.4.2 Dissolved oxygen concentrations at HB and BRR, rated poor for 2009.
The dashed line shows the NC State Standard of 5.0 mg/L.
0
1
2
3
4
5
6
7
8
9
10
11
12
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
HB
BRR
57
3.5 Cape Fear River Subbasin 03-06-18
Location: South River headwaters above Dunn down to Black River
Counties: Bladen, Cumberland, Harnett, Johnston, Sampson
Waterbodies: South River, Mingo Swamp
Municipalities: Dunn, Roseboro
NPDES Dischargers: 2 @ 0.08 million gallons per day
Concentrated Swine Operations: 105
LCFRP monitoring stations (DWQ #): SR (B8470000) DWQ monitoring stations: none
This subbasin is located on the inner coastal plain and includes the South River which
converges with the Great Coharie Creek to form the Black River, a major tributary of the
Cape Fear River. Land use is primarily agriculture including row crops and concentrated
animal operations.
58
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Not Rated 52.1 freshwater miles Supporting 52.1 freshwater miles Not Rated 1,454.2 freshwater acres No Data 242.5 freshwater miles
No Data 242.5 freshwater miles No Data 1,454.2 freshwater acres
Data collection: Since February 1996 Sampling relevance: Below City of Dunn, hog operations in watershed
UNCW Aquatic Ecology Laboratory Evaluation
SR – a slow black water tributary
SR had a poor rating for dissolved oxygen concentrations in 2009 (Table 3.5.1). The
North Carolina State Standard for swampwater of 4.0 mg/L was not met 58% of the time.
The lowest levels were found in summer and late fall (Figure 3.5.1). This station has had low dissolved oxygen problems for many years.
SR had a good rating for chlorophyll a exceeding the NC State standard of 40 µg/L on
only one occasion (Table 3.5.1).
SR had a fair water quality rating for fecal coliform bacteria concentrations exceeding
the NC state standard of 200 CFU/100mL in 25% of samples (Table 3.5.1). The highest concentration was in August (11,200 cfu/100mL).
SR had a good rating for field turbidity and total phosphorus (Table 3.5.1). The nitrate
rating was fair with samples exceeding the standard 17% of the time.
59
Table 3.5.1 UNCW AEL 2009 evaluation for subbasin 03-06-18
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SR P G F G F G
Figure 3.5.1 Dissolved oxygen (mg/L) at SR during 2009. The dashed line shows the NC
state standard for swampwater DO of 4.0 mg/L.
0
1
2
3
4
5
6
7
8
9
10
11
12
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
60
61
3.6 Cape Fear River Subbasin 03-06-19
Location: Three main tributaries of Black River near Clinton
Counties: Sampson
Waterbodies: Black River, Six Runs Ck., Great Coharie Ck., Little Coharie Ck. Municipalities: Clinton, Newton Grove, Warsaw NPDES Dischargers: 8 @ 6.8 million gallons per day Concentrated Swine Operations: 374
LCFRP monitoring stations (DWQ #):
LCO (B8610001), GCO (B8604000), 6RC (B8740000)
DWQ monitoring stations: none
62
This subbasin is located in the coastal plain within Sampson County. Land adjacent to the Black River is primarily undisturbed forest. There are numerous concentrated swine
operations within this subbasin.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 71.3 freshwater miles Supporting 153.0 freshwater
miles
Not Rated 99.7 freshwater miles Not Rated 8.8 freshwater miles
No Data 338.4 freshwater miles No Data 347.6 freshwater miles
Data collection: February 1996 to present
Sampling relevance: Many concentrated animal operations (CAOs) within the watershed, reference areas for point and nonpoint source pollution
UNCW Aquatic Ecology Laboratory Evaluation
GCO - blackwater stream, drains riparian wetlands
6RC, LCO and GCO all had a good rating for dissolved oxygen, chlorophyll a and field turbidity concentrations during 2009 (Table 3.6.1).
LCO and GCO had a good rating for fecal coliform during 2009. 6RC had a fair rating for
fecal coliform bacteria with 25% of samples exceeding the NC State human contact
standard of 200 CFU/100mL (Table 3.6.1).
Nitrate levels were rated poor at 6RC, LCO and GCO exceeding 200 µg/L in 100%, 50%,
and 58% of the samples, respectively (Table 3.6.1, Figure 3.6.1). All sites within this
subbasin had a good rating for total phosphorus concentrations (Table 3.6.1).
63
Table 3.6.1 UNCW AEL 2009 evaluation for subbasin 03-06-19
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
6RC G G F G P G
LCO G G G G P G
GCO G G G G P G
Figure 3.6.1 Nitrate concentrations (µg/L) at 6RC, LCO, and GCO during 2009. The
dashed line shows the UNCW-AEL standard of 200 µg/L.
0
200
400
600
800
1000
1200
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
6RC
LCO
GCO
64
65
66
67
3.7 Cape Fear River Subbasin 03-06-20
Location: Lower reach of Black River
Counties: Pender
Waterbodies: Black River, Colly Creek, Moores Creek Municipalities: Town of White Lake, Currie, Atkinson NPDES Dischargers: 2 at 0.82 million gallons per day Concentrated Swine Operations: 18 LCFRP monitoring stations (DWQ #):
COL (B8981000), B210 (B9000000), BBT (none)
DWQ monitoring stations: none
68
This subbasin is located on the coastal plain in Pender County and the land is mostly
forested with some agriculture. The streams in this watershed typically have acidic black waters. The Black River in this area has been classified as Outstanding Resource Waters
(ORW) (NCDENR DWQ Cape Fear River Basinwide Water Quality Plan, October 2005).
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 13.0 freshwater miles Supporting 34.9 freshwater miles
Not Rated 77.9 freshwater miles No Data 199.8 freshwater miles Not Rated 576.0 freshwater acres No Data 576.0 freshwater miles
No Data 143.8 freshwater acres
Data collection: February 1996 to present
UNCW Aquatic Ecology Laboratory Evaluation
Sampling relevance: Colly Creek is a pristine swamp reference site, B210 and BBT are
middle and lower Black River sites
COL – blackwater stream, drains swamp area, very low pH
B210- Black River at Hwy 210 bridge
69
All three sites had a good rating for dissolved oxygen when using the NC State swampwater standard of 4.0 mg/L (Table 3.7.1).
Chlorophyll a and field turbidity concentrations were low for each site within this
subbasin and all sites had a good rating for these parameters (Table 3.7.1).
Fecal coliform bacteria concentrations were low with B210 and COL rated as good (Table 3.7.1). BBT samples were not analyzed for fecal coliform bacteria.
B210 and COL rated good for both nutrient species. BBT samples were not analyzed for
nutrients.
Table 3.7.1 UNCW AEL 2009 evaluation for subbasin 03-06-20
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
B210 G G G G G G
COL G G G G G G
BBT G G G
70
71
3.8 Cape Fear River Subbasin 03-06-21
Location: Headwaters of NE Cape Fear River below Mount Olive
Counties: Duplin, Wayne
Waterbodies: Northeast Cape Fear River Municipalities: Mount Olive NPDES Dischargers: 6 @ 1.4 million gallons per day Concentrated Swine Operations: 75
LCFRP monitoring stations (DWQ#): NC403 (B9090000) DWQ monitoring
stations: NC403
This subbasin includes the headwaters of the Northeast Cape Fear River and small
tributaries. This section of the NE Cape Fear River is very slow moving and somewhat
congested with macrophytic growth. Most of the watershed is forested and there is
significant agriculture in the basin.
72
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 21.7 freshwater miles Supporting 57.3 freshwater miles Not Rated 38.9 freshwater miles No Data 88.1 freshwater miles
No Data 84.7 freshwater miles
Data collection: June 1997 – present Sampling relevance: Below Mount Olive Pickle Plant
UNCW Aquatic Ecology Laboratory Evaluation
NC403 - slow moving headwaters of NE Cape Fear River
NC403 had a poor rating for dissolved oxygen concentrations, not meeting the NC State
Standard for swampwater of 4.0 mg/L in 50% of the samples (Table 3.8.1, Figure 3.8.1)
NC403 had a good rating for chlorophyll a yet had very high aquatic macrophyte biomass present, often times completely covering and blocking the waterway (Table
3.8.1). As we have noticed at several of our stations over the years, chlorophyll a, a
measurement of phytoplankton biomass, often used as an indicator of eutrophic
conditions, is not always adequate to determine problematic conditions with regard to
aquatic flora.
NC403 had a fair rating for fecal coliform bacteria with samples exceeding the NC
State standard for human contact (200 cfu/100 mL) 17% of the time.
Field turbidity was rated as good at NC 403 (Table 3.8.1).
High nitrate levels at NC403 led to a poor rating, with nitrate concentrations >200 µg/L for
50% of the samples (Table 3.8.1, Figure 3.8.1). UNCW AEL researchers are concerned about the elevated nitrate levels that are periodically found at this site since these levels
73
increase the likelihood of algal blooms and excessive aquatic macrophyte growth. Total phosphorus had a fair rating for 2009, exceeding the AEL standard 17% of the time.
Table 3.8.1 UNCW AEL 2009 evaluation for subbasin 03-06-21
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
NC403 P G F G P F
Figure 3.8.1 Dissolved oxygen (mg/L) and nitrate (µg/L) concentrations at NC403 during 2009. The dashed lines show the NC State DO standard of 4.0 mg/L for swampwater and
the UNCW AEL standard for Nitrate of 200 µg/L.
0
2
4
6
8
10
12
0
500
1000
1500
2000
2500
3000
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Di
s
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
Ni
t
r
a
t
e
(
µg/
L
)
Nitrate
DO
74
3.9 Cape Fear River Subbasin 03-06-22
Location: NE Cape Fear River and tributaries in the vicinity of Kenansville Counties: Duplin Waterbodies: Northeast Cape Fear River, Rockfish Creek Municipalities: Beulaville, Kenansville, Rose Hill and Wallace
NPDES Dischargers: 13 @ 9.9 million gallons per day
Concentrated Swine Operations: 449
LCFRP monitoring stations (DWQ #):
PB (B9130000), GS (B9191000), SAR (B9191500), LRC (9460000) ROC
(B9430000)
DWQ monitoring stations: none
75
Land coverage in this watershed is mostly forested with significant agriculture including row crops and a dense concentration of animal operations (poultry and swine).
The CFR Basinwide Water Quality Plans lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting Not Rated
Impaired
No Data
51.1 freshwater miles 72.1 freshwater miles
50.1 freshwater miles
408.8 freshwater miles
Supporting Not Rated
No Data
73.2 freshwater miles 3.0 freshwater miles
505.9 freshwater miles
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: February 1996 to present
Sampling relevance: Below point and non-point source discharges
PB – slow moving swamp-like stream ROC - Rockfish Creek below Wallace
All sites in this subbasin were rated using the dissolved oxygen NC State swampwater
standard of 4.0 mg/L. SAR, PB, LRC and ROC all had a good rating (Table 3.9.1). GS
had a poor rating with DO values dropping below the standard 50% of the time.
For chlorophyll a concentrations all sites had a good rating (Table 3.9.1).
For fecal coliform bacteria concentrations GS had a good rating (Table 3.9.1). SAR, PB LRC and ROC each had a poor rating with 42%, 75% 50% and 50% of samples above the standard, respectively. Fecal coliform bacteria concentrations are shown graphically
in Figure 3.9.1 and 3.9.2.
All sites had a good rating for field turbidity concentrations (Table 3.9.1). Mean levels
were <
15 NTU for all sites within this subbasin for 2009.
76
For nitrate GS had a fair rating with levels exceeding the UNCW AEL standard (200 µg/L)
17% of the time (Table 3.9.1). SAR, PB, LRC and ROC all had a poor rating with levels exceeding the UNCW AEL standard 50%, 67%, 42% and 100% of the time, respectively.
Nitrate levels for SAR, PB, LRC and ROC are shown graphically in Figure 3.9.3 and
3.9.4.
For total phosphorus all stations had a good rating except PB. PB was rated fair,
exceeding the UNCW AEL standard of 500 mg/L in 25% of the samples (Table 3.9.1).
Table 3.9.1 UNCW AEL 2009 evaluation for subbasin 03-06-22
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SAR G G P G P G
GS P G G G F G
PB G G P G P F
LRC G G P G P G
ROC G G P G P G
Figure 3.9.1 Fecal coliform bacteria (cfu/100mL) at SAR and PB, both rated poor during 2009. The dashed line is the NC State Standard for human contact of 200 cfu/100mL).
0
200
400
600
800
1,000
1,200
1,400
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
)
SAR
PB
77
Figure 3.9.2 Fecal coliform bacteria (cfu/100mL) at LRC and ROC, both rated poor
during 2009. The dashed line is the NC State Standard for human contact of 200
cfu/100mL).
0
200
400
600
800
1,000
1,200
1,400
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
)
LRC
ROC
Figure 3.9.3 Nitrate-N concentrations (µg/L) at SAR and PB, both rated poor during
2009. The dashed line represents the UNCW AEL standard of 200 µg/L.
78
0
200
400
600
800
1000
1200
1400
1600
1800
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
SAR
PB
Figure 3.9.4 Nitrate-N concentrations (µg/L) at LRC and ROC, both rated poor during
2009. The dashed line represents the UNCW AEL standard of 200 µg/L.
0
200
400
600
800
1000
1200
1400
1600
1800
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
LRC
ROC
79
80
81
3.10 Cape Fear River Subbasin 03-06-23
Location: Area near Burgaw and Angola swamp
Counties: Pender
Waterbodies: Northeast Cape Fear River,Burgaw Creek Municipalities: Burgaw NPDES Dischargers: 7 @ 3.8 million gallons per day Concentrated Swine Operations: 52
LCFRP monitoring stations (DWQ #):
ANC (69), BCRR (82), BC117 (83), NCF117 (84), NCF6 (85)
DWQ monitoring stations: NCF117
This subbasin is located in the outer coastal plain where many streams are slow flowing
blackwater streams that often dry up during the summer months. Most of the watershed
82
is forested with some agriculture and increasing human development.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 73.8 freshwater miles Supporting 39.5 freshwater miles
Not Rated 45.1 freshwater miles Supporting 1.0 saltwater acre
Impaired 23.4 freshwater miles Not Rated 11.6 freshwater miles
No Data 233.2 freshwater miles Not Data 324.5 freshwater miles
Not Rated 1.0 saltwater acre
UNCW Aquatic Ecology Laboratory Evaluation
Data collection: NCF117 & NCF6 since June 1995, others from February 1996
Sampling relevance: point and non-point source dischargers
ANC - Angola Creek BC117 - Burgaw Canal at US 117
NCF117 - Northeast Cape Fear River at US117
83
For dissolved oxygen BC117, NCF117, NCF6 and SC-CH had a good rating when using
the 4.0 mg/L standard (Table 3.10.1). ANC and BCRR had a fair rating with sub-standard samples 17% and 25% of the time, respectively.
For chlorophyll a all sites rated good during 2009 (Table 3.10.1). Chlorophyll a was not
analyzed at SC-CH.
For fecal coliform bacteria ANC, NCF117, NCF6 and SC-CH had a good rating (Table
3.10.1). BC117 and BCRR each had a poor rating exceeding the human contact
standard 58% and 83% of the time, respectively. Fecal coliform bacteria concentrations for BC117 and BCRR are shown in Figure 3.10.1.
Four of the five stations were rated good for field turbidity. NCF6 was rated fair with
values exceeding the NC State Standard for tidal waters of 25 NTU 25% of the time
(Table 3.10.1).
Nutrient loading of nitrate and total phosphorus was problematic at BC117 which had a
poor rating for both (Table 3.10.1). Nitrate levels exceeded the UNCW AEL standard
100% of the time and total phosphorus levels exceeded the UNCW AEL standard 75% of
the time. BC117 had the highest nitrate and TP levels seen in the LCFRP system. These
levels were far above the concentrations known to lead to algal bloom formation,
bacterial increases and increased biochemical oxygen demand (BOD) in blackwater
streams (Mallin et al. 2001, Mallin et al. 2002). NCF6 was rated fair for nitrate exceeding
the UNCW AEL standard 25% of the time. ANC and BCRR were both rated poor for nitrate as well, exceeding the UNCW AEL standard 33% of the time. Nutrients were not
analyzed at SC-CH.
Table 3.10.1 UNCW AEL 2009 evaluation for subbasin 03-06-23
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
ANC F G G G P G
BC117 G G P G P P
BCRR F G P G P G
NCF117 G G G G G G
NCF6 G G G F F G
SC-CH P G G
84
Figure 3.10.1 Fecal coliform bacteria concentrations (cfu/100mL) at BC117 and BCRR during 2009. The dashed line shows the NC State Standard for human contact, 200
cfu/100 mL.
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Fe
c
a
l
C
o
l
i
f
o
r
m
B
a
c
t
e
r
i
a
(
c
f
u
/
1
0
0
m
L
)
BC117
BCRR
85
86
87
3.11 References Cited
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001. Effect of nitrogen
and phosphorus loading on plankton in Coastal Plain blackwater streams. Journal
of Freshwater Ecology 16:455-466.
Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002. Seeking science-based nutrient standards for coastal blackwater stream systems. Report No. 341.
Water Resources Research Institute of the University of North Carolina, Raleigh,
N.C.
Mallin, M. A., M.R. McIver, S.H. Ensign and L.B. Cahoon. 2004. Photosynthetic and heterotrophic impacts of nutrient loading to blackwater streams. Ecological
Applications14: 823-838.
NCDENR-DWQ (North Carolina Department of Environment and Natural Resources-
Division of Water Quality), Cape Fear River Basinwide Water Quality Plan. July 2000, Raleigh, N.C.
NCDENR-DWQ (North Carolina Department of Environment and Natural Resources-
Division of Water Quality), Cape Fear River Basinwide Water Quality Plan. October
2005, Raleigh, N.C.
88