Lower Cape Fear River Program 2008 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2008
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
October 2009
CMS Report No. 09-06
Center for Marine Science
University of North Carolina Wilmington
Wilmington, N.C. 28409
Executive Summary
Multiparameter water sampling for the Lower Cape Fear River Program (LCFRP) has
been ongoing since June 1995. Scientists from the University of North Carolina
Wilmington (UNCW) 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 the period January - December 2008. 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 are rare because light is attenuated by water color or turbidity, and flushing is 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 2008 were similar to the average for 1996-2007. 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 2008 DO levels occurred at the lower river and
upper estuary stations DP, BBT, IC, NAV, HB, BRR and M61 (6.2-6.9 mg/L). As the
water reaches the lower estuary higher algal productivity, mixing and ocean dilution help
alleviate oxygen problems. For this low water year we rated one several stations as fair (DO less than 5.0 mg/L on 11-25% of occasions sampled); HB, BRR, M61, DP and IC.
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 2008 Stations NCF117 and B210,
2
representing those rivers, had average DO concentrations of 6.4 and 6.8 mg/L, respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2008. Stations BCRR (upper Burgaw Creek) and SR (South
River) had DO levels below 4.0 mg/L 58% of the occasions sampled, with LVC2
(Livingston Creek) 42%, NC403 (Northeast Cape Fear River headwaters) 33% and ANC (Angola Creek), GS (Goshen Swamp) and HAM (Hammond Creek) 25%. Smith Creek (SC-CH) had DO levels below 5.0 mg/L 33% of the time. Considering all sites
sampled in 2008, we rated 19% as poor for dissolved oxygen, 28% as fair, and 53% as
good.
Annual mean turbidity levels for 2008 were considerably lower than the long-term average, probably a result of low rainfall and lower river discharge. Highest mean
turbidities were at the upper estuary site NAV (25 NTU), and the upper river sites N11
(26 NTU), AC (25 NTU) and DP (19 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, LVC2 and PB (Panther Branch). Algal blooms occurred more frequently than usual, particularly from June through September 2008.
In the estuary blooms occurred from M61 through M35, and stream stations strongly
impacted by algal blooms included ANC, GS, NC403, PB, LRC (Little rockfish Creek)
and BCRR. This was a considerable increase over both 2006 and 2007, possibly a result of lower flow (better bloom formation conditions for phytoplankton) yet sufficient nitrogen and phosphorus availability. Several stream stations, particularly BC117,
BCRR, ROC, PB, BRN (Browns Creek), HAM, SAR (Northeast Cape Fear River near
Sarecta), NC403, GS 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 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 2008 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.
3
For the 2008 period UNCW rated 83% of the stations as good in terms of chlorophyll a,
with one (PB) rated as poor and four (ANC, GS, NC403 and BCRR) rated as fair. For
turbidity all of the sites were rated good except for SC-CH, which was rated poor with
the brackish water standard of 25 NTU exceeded 33% of occasions sampled. Fecal
coliform bacteria counts showed poorer water quality in 2008 compared to 2007, with 52% of the sites rated as poor or fair compared with 41% in 2007. 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, 47% of the sites were
rated poor or fair for dissolved oxygen, slightly less than in 2007. In addition, by our
UNCW standards excessive nitrate and phosphorus concentrations were problematic at a number of stations (Chapter 3).
4
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…………………43
5
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 2008.
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
13-year (1995-2008) data base freely 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
6
program involved cooperative sampling with the North Carolina Division of Marine Fisheries and the North Carolina Wildlife Resources Commission. The fisheries
program ended in December 1999, but was renewed with additional funds from the Z.
Smith Reynolds Foundation from spring – winter 2000, and has been operational
periodically for special projects since that period. 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. 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). 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 sampled on Smith Creek at Castle Hayne Road (Table 1.1).
7
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.
8
Table 1.1. Description of sampling locations in the Cape Fear Watershed, 2008, 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
9
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
10
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
11
Figure 1.1 Map of the Lower Cape Fear River system and the LCFRP sampling stations.
12
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 2008 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
13
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 directly from the 1.0 micron filters used for filtering samples for
orthophosphate analysis. All filters were wrapped individually in foil, placed in airtight containers and stored in the freezer. During analysis each filter is immersed in 10 mL of
14
90% acetone for 24 hours, which extracts the chlorophyll a into solution. Chlorophyll a
concentration of each solution is measured on a Turner 10-AU fluorometer. The
fluorometer uses an optimal combination of excitation and emission bandwidth filters which
reduces the errors inherent in the acidification technique. 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 2008. Discussion of the
data focuses both on the river channel stations and stream stations, which sometimes
reflect poorer water quality than mainstem staions. 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.
15
Physical Parameters
Water temperature
Water temperatures at all stations ranged from 6.0 to 32.3oC and individual station annual averages ranged from 16.5 to 20.9oC (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 ranged from 0.1 to 35.2 practical salinity units (psu) and
station annual means ranged from 1.3 to 30.8 psu (Table 2.2), somewhat lower than in
2007. Lowest salinities occurred in December and highest salinities occurred in July. We note that average river discharge as computed by the U.S. Geological Survey (USGS) for 2008 was 3,201 CFS, compared with 5,119 CFS in 2007 and 3,301 CFS in 2006; see
http://nc.water.usgs.gov/realtime/real_time_cape_fear.html. In the mid-to-lower estuary
annual mean salinity for 2008 was higher than that of the twelve-year average for 1996-
2007 for all stations (Figure 2.1), due to low runoff and discharge conditions. 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 0.11 to 53.5 mS/cm and from 0.0 to 13.91 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 3.7 to 8.1 and station annual medians ranged from 3.9 to 8.0
(Table 2.4). pH was typically lowest upstream due to acidic swamp water inputs and
highest downstream as alkaline seawater mixes with the river water. Low pH values at
COL predominate because of naturally acidic blackwater inputs at this near-pristine stream station.
Dissolved Oxygen
Dissolved oxygen (DO) problems are a major water quality concern in the lower Cape Fear River and its estuary, and several of the tributary streams (Mallin et al. 1999; 2000; 2001a;
16
2001b; 2002a; 2002b; 2003; 2004; 2005a; 2006a; 2006b; 2007; 2008). Surface concentrations for all sites in 2008 ranged from 0.2 to 12.0 mg/L and station annual means
ranged from 4.1 to 9.6 mg/L (Table 2.5). Average annual DO levels at the river channel
and estuarine stations for 2008 were very similar to the average for 1996-2007 (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 middle
estuary at stations M42 and M35. Lowest mainstem mean 2008 DO levels occurred at the
lower river and upper estuary stations IC, NAV, HB, BRR and M61 (6.6-6.9 mg/L). NAV had DO concentrations less than 4.0 mg/L 17% of occasions sampled, and IC, NCF6, HB, BRR and M61 were below 5.0 mg/L 25% of the time. 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 2008 mean = 6.4, NCF6 = 6.7, B210 2008 mean =
6.8). 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 2008 Stations NCF117 DO concentrations were again somewhat lower
than at B210 (means 6.4 and 6.8 mg/L, respectively). Several stream stations were severely stressed in terms of low dissolved oxygen during the year 2008. Stations SR and
17
BCRR had DO levels below 4.0 mg/L 58% of the occasions sampled, with LVC2 42%, NC403 33%, and ANC, GS and HAM 25% (Table 2.5). Smith Creek had DO levels below
5.0 mg/L 33% of the time. 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 47% of the sites impacted in 2008.
Field Turbidity
Field turbidity levels ranged from 0 to 145 nephelometric turbidity units (NTU) and station annual means ranged from 1 to 26 NTU (Table 2.6). Annual mean turbidity levels for 2008
were considerably lower than the long-term average at the main river and estuarine
stations (Fig. 2.3) probably a result of low river discharge and a lack of major stormwater
runoff activity. Highest mean turbidities were at NC11 (26 NTU), NAV (25 NTU) and AC (25 NTU) with turbidities generally low in the middle to lower estuary (Figure 2.3). Turbidity was lower in the blackwater tributaries (Northeast Cape Fear River and Black
River) than in the mainstem river.
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 96 mg/L with station
annual means from 2 to 19 mg/L (Table 2.7). The overall highest values were at NCF6,
followed by the upper river stations NC11, and AC, and the upper estuary site NAV. In the
stream stations TSS was generally considerably lower than the river and estuary, except for BCRR and 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.
18
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 0.74 to 7.77/m and station annual means ranged from 1.25 at M18 to 4.22 /m at NAV (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 50 to 27,300 µg/L and station annual means ranged from 371
to 12,557 µg/L (Table 2.9). Mean total nitrogen in 2008 was slightly higher than the twelve-year mean at most river stations, but lower than the mean in the 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 at NC11, 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 12,557 µg/L, likely from the upstream Town of Burgaw wastewater discharge. ROC and LVC2 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 27,300 µg/L and station annual means ranged from 45 to 11,832 µg/L (Table 2.10). The
highest average riverine nitrate levels were at AC (764 µg/L) and NC11 (739 µg/L)
indicating that much of this nutrient is imported from upstream. Moving downstream,
nitrate levels decrease most likely as a result of uptake by primary producers, microbial
19
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 = 283 µg/L) and the Black
River (B210 = 220 µg/L). No clear temporal pattern was observable for nitrate.
Several stream stations showed high levels of nitrate on occasion including BC117, ROC, 6RC, LVC2, NC403 and LCO. NC403 and LVC2 are downstream of industrial wastewater discharges and LCO, 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 1,810 µg/L and station annual
means ranged from 5 to 676 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, andM54, 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, PB, GS and especially LVC2 (below point sources), 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 9,200 µg/L and station annual means ranged
from 188 to 1,905 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
anomalous peak of 6,200 µg/L of TN was seen at M42 in July; this was a real number
according to the laboratory, but clearly an isolate, and rare excursion in that area of the estuary. Likewise an unusual peak of 9,200 µg/L occurred at AC in March.
20
Total Phosphorus
Total phosphorus (TP) concentrations ranged from below detection limit to 3,860 µg/L and
station annual means ranged from 31 to 1,576 µg/L (Table 2.13). Mean TP for 2008 was approximately equal to the twelve-year mean in all areas except the Northeast Cape Fear River, where it was much higher than the mean (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, GS and NC403. Some of these stations (BC117,
NC403) are downstream of industrial or wastewater discharges, while GS and GCO are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 2,820 µg/L and station annual means ranged
from 7 to 1,108 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
estuary because of settling, and orthophosphate concentration also declines. In the
estuary, primary productivity helps reduce orthophosphate concentrations by assimilation
into biomass. Orthophosphate levels typically reach maximum concentrations during summertime, when anoxic sediment releases bound phosphorus. Also, in the Cape Fear
Estuary, summer algal productivity is limited by nitrogen, thereby allowing the
accumulation of orthophosphate (Mallin et al. 1997; 1999). In spring, productivity in the
estuary is usually limited by phosphorus (Mallin et al. 1997; 1999).
The stream station BC117 had very high orthophosphate levels, and ROC and GCO had
comparatively high levels. BC117 is below a municipal wastewater discharge, and ROC
and GCO are impacted by agriculture/animal waste runoff.
21
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 chlorophyll a was moderate in the river but relatively high at
the estuarine stations (Table 2.15). At many of the estuarine stations chlorophyll a for
2008 was approximately double that of the twelve-year mean for those sites (Figure 2.6).
Two moderate algal blooms occurred at Station NC11, with chlorophyll a levels of 24 µg/L
in July and 34 µg/L in August. 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. System wide, chlorophyll
a ranged from undetectable to 376.0 µg/L and station annual means ranged from 1.4 –
41.9 µg/L; these numbers represent a considerable increase in phytoplankton production
throughout the system compared with 2007. 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. However, in 2008 phytoplankton biomass as chlorophyll a was unusually elevated from
M61 to M35 during the months of June – September (Table 2.15).
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, the
low flow conditions prevailing in 2008 allowed for clearer water through less suspended
material and less blackwater swamp inputs. Thus, chlorophyll a concentrations in the estuary were larger than the average for the preceding eleven years (Figure 2.6). Highest chlorophyll a concentrations were found from June through September in both the main
channels and at the stream stations.
Substantial phytoplankton blooms occasionally occur at the stream stations, with more than usual occurring in 2008 (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
22
waters (Mallin et al. 2001a; 2002a; 2004; 2006b). Stream algal blooms in 2008 were particularly high at GS, PB, NC403, BCRR and ANC (Table 2.15).
Biochemical Oxygen Demand
For the mainstem river, mean annual five-day biochemical oxygen demand (BOD5) concentrations were approximately equivalent between NC11 and AC, suggesting that in
2008 (as was the case with 2007) there were no discernable effects of BOD loading from
the nearby pulp/paper mill inputs (Table 2.16). BOD was somewhat lower during the
winter than summer. Results of 2008 BOD analyses from several stream stations in the Northeast Cape Fear
River watershed can be seen in Table 2.16. ANC, GS, and N403 all showed large (> 4.3
mg/L) individual BOD5 measurements during 2008, particularly during summer. Station
N403 is below point sources, but the other two sites are non-point runoff areas. Fecal Coliform Bacteria
Fecal coliform (FC) bacterial counts ranged from 1 to >30,000 CFU/100 mL and station
annual geometric means ranged from 5 to 788 CFU/100 mL (Table 2.17). The state human contact standard (200 CFU/100 mL) was exceeded at the mainstem sites only rarely in 2008. Geometric mean fecal coliform counts in 2008 in the Cape Fear, Black, and
Northeast Cape Fear Rivers were high compared with the twelve-year average, whereas
the estuarine counts were approximately equal to the long-term geometric means (Figure
2.7). All stream stations surpassed the state standard for human contact of 200 CFU/100 mL on
at least one occasion and many were particularly problematic. During 2008 BC117
exceeded the state standard 100% of the time; BRN 58%, 6RC, SAR and HAM 50%, PB,
ROC, and BCRR 42%, N403 and SR 33%, and ANC, GS, LRC 25% of the time. BC117, NC403, and PB are located below point source discharges and the other sites are primarily influenced by non-point source pollution. Overall, elevated fecal coliform counts are
problematic in this system, with 52% of the stations impacted in 2008, a worsening from
the previous year 2007.
2.4 - References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed.
American Public Health Association, Washington, D.C.
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.
23
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.
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.
24
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.
25
Table 2.1 Water temperature (oC) during 2008 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 11.0 10.8 11.1 11.5 11.7 11.6 11.8 11.9 11.3 JAN 9.6 9.9 9.6 9.5 9.4 11.5
FEB 13.1 13.3 13.2 13.8 13.7 13.4 13.6 13.6 13.1 13.0 FEB 11.8 11.9 12.3 12.3 12.7 12.9
MAR 13.4 14.1 14.2 14.1 14.7 14.9 15.0 14.9 14.4 14.8 MAR 12.5 13.2 13.2 13.7 13.2 13.4
APR 19.9 19.7 20.0 20.7 20.3 20.8 20.5 19.8 19.4 20.2 APR 17.5 17.6 17.7 16.6 17.2 17.9
MAY 22.3 22.8 23.3 22.5 22.4 22.7 22.6 22.3 21.7 21.9 MAY 21.5 22.1 21.3 21.4 21.9 23.0
JUN 25.6 26.0 25.9 26.2 26.8 26.4 29.3 29.1 28.2 28.7 JUN 27.7 28 27.8 27.6 28.4 27.9
JUL 29.5 30.0 30.0 29.9 28.9 28.6 28.2 28.0 27.8 28.2 JUL 28.9 29.4 29.1 29.2 29.1 28.5
AUG 31.3 31.4 32.3 31.7 30.8 30.8 31.2 30.3 30.2 30.5 AUG 27.9 28.0 27.1 26.8 27.7 28.5
SEP 27.5 28.5 28.5 28.5 28.2 28.1 28.7 28.0 28.3 28.1 SEP 26.3 26.1 26.3 26.2 29.1 27.9
OCT 23.4 24.4 23.4 23.7 23.5 24.3 24.7 25.4 24.9 24.6 OCT 21.8 22.2 22.1 21.9 22.3 23.1
NOV 15.4 15.7 15.8 16.3 16.2 16.2 16.3 16.5 16.4 15.4 NOV 13.3 13.2 13.0 12.3 13.2 14.3
DEC 8.6 8.7 9.3 10.3 10.2 10.5 10.6 11.3 11.4 10.8 DEC 10.9 11.1 11.3 11.5 11.8 12.0
mean 20.0 20.5 20.6 20.7 20.6 20.7 21.0 20.9 20.6 20.6 mean 19.1 19.4 19.2 19.1 19.7 20.1
std dev 7.8 7.8 7.8 7.5 7.2 7.1 7.4 7.2 7.1 7.4 std dev 7.4 7.4 7.2 7.2 7.6 7.1
median 21.1 21.3 21.7 21.6 21.4 21.8 21.6 21.1 20.6 21.1 median 19.5 19.9 19.5 19.0 19.6 20.5
max 31.3 31.4 32.3 31.7 30.8 30.8 31.2 30.3 30.2 30.5 max 28.9 29.4 29.1 29.2 29.1 28.5
min 8.6 8.7 9.3 10.3 10.2 10.5 10.6 11.3 11.4 10.8 min 9.6 9.9 9.6 9.5 9.4 11.5
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 10.9 13.2 13.2 12.3 13.4 13.5 12.4 15.3 11.2 JAN 6.9 6.9 7.3 7.4 9.8 6.6 JAN 10.3 10.2 11.8 9.3 11.8
FEB 17.5 16.5 17.1 15.6 15.3 13.8 15.9 16.4 13.4 FEB 9.7 9.1 10.3 9.3 11.6 10.3 FEB 11.5 14.1 14.1 11.6 11.6
MAR 15.7 14.9 15.3 15.2 12.8 13.8 15.9 12.7 14.2 MAR 12.8 12.5 13.7 13.2 13.7 13.2 MAR 12.9 14.1 15.1 13.6 15.4
APR 18.0 16.2 16.6 17.2 16.2 16.7 16.4 16.0 15.9 APR 16.0 15.5 15.5 15.6 15.5 15.2 APR 17.4 16.4 15.5 17.5 18.0
MAY 22.2 17.8 21.8 23.3 24.8 22.1 20.7 18.9 19.8 MAY 20.9 21.0 21.3 20.8 20.6 19.3 MAY 21.8 20.4 18.1 19.8 22.2
JUN 30.2 30.1 29.6 30.2 30.9 29.4 27.1 26.2 25.0 JUN 25.3 24.7 26.1 23.0 20.7 20.8 JUN 29.3 30.6 27.7 28.0 30.6
JUL 28.0 26.5 26.7 26.8 27.2 26.5 26.5 25.6 24.5 JUL 22.7 22.8 25.0 24.7 22.9 22.3 JUL 28.5 28.6 27.0 28.8
AUG 25.3 23.5 24.4 23.3 22.9 23.0 22.3 21.9 21.7 AUG 26.9 26.5 26.7 26.6 27.0 25.4 AUG 30.5 29.5 26.7 28.5 30.9
SEP 25.3 24.7 25.2 24.5 25.7 23.5 23.2 22.6 22.7 SEP 24.5 24.3 24.8 24.3 24.3 23.3 SEP 27.6 25.3 23.8 25.4 28.1
OCT 20.8 19.9 20.5 20.5 20.2 19.5 21.0 19.3 20.1 OCT 18.1 18.2 18.4 18.7 18.6 17.7 OCT 21.2 18.8 17.2 18.6 22.8
NOV 7.8 7.0 8.0 7.8 7.0 7.9 6.6 8.2 6.3 NOV 13.5 13.3 13.8 13.2 14.4 13.3 NOV 11.5 8.5 7.0 8.3 11.5
DEC 7.4 6.2 8.2 7.1 6.0 7.2 6.1 7.3 6.1 DEC 10.0 9.6 9.7 9.0 10.6 10.3 DEC 10.2 10.6 12.5 12.3 12.0
mean 19.1 18.0 18.9 18.7 18.5 18.1 17.8 17.5 16.7 mean 17.3 17.0 17.7 17.1 17.5 16.5 mean 19.4 18.9 17.2 18.3 20.3
std dev 7.6 7.4 7.0 7.4 8.0 7.1 6.9 6.1 6.6 std dev 6.8 6.8 7.0 6.8 5.7 5.9 std dev 8.1 7.9 6.5 7.5 7.9
median 19.4 17.2 18.8 18.9 18.2 18.1 18.6 17.7 17.9 median 17.1 16.9 17.0 17.2 17.1 16.5 median 19.3 17.6 15.5 18.1 20.1
max 30.2 30.1 29.6 30.2 30.9 29.4 27.1 26.2 25.0 max 26.9 26.5 26.7 26.6 27.0 25.4 max 30.5 30.6 27.7 28.5 30.9
min 7.4 6.2 8.0 7.1 6.0 7.2 6.1 7.3 6.1 min 6.9 6.9 7.3 7.4 9.8 6.6 min 10.2 8.5 7.0 8.3 11.5
26
Table 2.2 Salinity (psu) during 2008 at the Lower Cape Fear River Program estuarine stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD NCF6
JAN 3.3 5.4 4.6 8.4 10.8 13.8 20.4 25.1 31.2 27.4 7.6
FEB 0.1 0.5 1.1 5.9 8.0 9.6 14.3 23.9 27.6 28.3 0.3
MAR 0.1 0.1 0.1 0.4 1.5 4.6 10.2 20.2 30.4 21.4 0.1
APR 0.1 0.1 0.1 4.0 6.5 7.2 13.6 21.8 29.0 22 0.1
MAY 1.3 2.3 1.2 3.1 8.2 10.8 16.9 25.5 31.8 27.1 1.6
JUN 2.1 5.8 7.3 11.8 13.8 17.3 21.5 27.6 31.6 32.9 4.6
JUL 1.2 3.1 5.5 12.3 18.4 21.0 24.3 31.9 34.2 35.2 12.0
AUG 5.9 6.6 8.3 13.0 16.8 19.9 22.8 32.5 34.6 32.1 13.3
SEP 0.5 1.2 0.8 4.3 7.9 12.1 19.8 29.1 32.0 29.2 5.8
OCT 1.1 1.6 0.8 3.0 7.1 12.3 16.1 25.3 33.3 29.7 0.7
NOV 0.3 4.5 8.9 13.6 15.8 17.8 21.4 27.7 30.2 30.9 0.4
DEC 0.1 0.1 2.0 7.7 8.2 10.6 12.9 19.6 24.0 24.9 0.2
mean 1.3 2.6 3.4 7.3 10.3 13.1 17.9 25.9 30.8 28.4 3.9
std dev 1.7 2.4 3.3 4.5 5.0 5.1 4.5 4.2 2.9 4.2 4.8
median 0.8 2.0 1.6 6.8 8.2 12.2 18.4 25.4 31.4 28.8 1.2
max 5.9 6.6 8.9 13.6 18.4 21.0 24.3 32.5 34.6 35.2 13.3
min 0.1 0.1 0.1 0.4 1.5 4.6 10.2 19.6 24.0 21.4 0.1
27
0
5
10
15
20
25
30
35
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, 1995-2007
versus 2008.
1995-2007
2008
28
Table 2.3 Specific Conductivity (mS/cm) during 2008 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 6.06 9.59 8.24 14.42 18.27 22.83 32.67 39.44 47.94 42.68 JAN 0.12 0.16 0.20 0.19 0.26 13.16
FEB 0.20 1.06 2.14 10.39 13.70 16.26 23.55 35.64 43.00 43.85 FEB 0.14 0.14 0.21 0.15 0.18 0.60
MAR 0.11 0.11 0.16 0.72 2.91 8.22 17.32 32.25 46.71 34.05 MAR 0.10 0.27 0.18 0.10 0.13 0.22
APR 0.15 0.15 0.31 7.16 11.40 12.54 22.48 34.72 44.79 34.89 APR 0.09 0.11 0.12 0.08 0.09 0.15
MAY 2.56 4.32 2.26 5.69 14.14 18.25 27.55 39.75 48.61 42.09 MAY 0.09 0.13 0.14 0.12 0.14 3.02
JUN 3.94 10.28 12.69 19.87 22.89 28.18 34.40 43.03 48.52 50.45 JUN 0.15 0.29 0.23 0.23 0.28 8.31
JUL 2.29 5.77 9.90 20.76 29.82 33.64 38.33 49.00 52.12 53.50 JUL 0.15 0.35 0.32 0.32 0.57 20.28
AUG 10.55 11.85 14.43 21.75 27.61 32.06 36.30 49.91 52.85 49.36 AUG 0.15 0.20 0.17 0.16 0.21 22.20
SEP 1.11 1.77 1.60 7.79 13.72 20.26 31.90 44.93 49.18 45.20 SEP 0.10 0.11 0.14 0.11 0.14 10.35
OCT 2.05 3.06 1.57 5.59 12.31 20.57 26.35 39.65 50.76 45.56 OCT 0.10 0.10 0.12 0.11 0.13 1.42
NOV 0.68 8.01 15.22 22.37 25.82 28.84 34.03 42.95 46.37 47.36 NOV 0.12 0.12 0.14 0.12 0.14 0.85
DEC 0.14 0.17 3.83 13.31 14.06 17.86 21.50 31.51 37.89 39.16 DEC 0.08 0.10 0.10 0.10 0.10 0.38
mean 2.49 4.68 6.03 12.48 17.22 21.63 28.86 40.23 47.39 44.01 mean 0.11 0.17 0.17 0.15 0.20 6.74
std dev 3.12 4.32 5.72 7.37 7.87 7.80 6.68 6.03 4.13 5.93 std dev 0.02 0.08 0.06 0.07 0.13 8.09
median 1.58 3.69 3.05 11.85 14.10 20.42 29.72 39.70 48.23 44.52 median 0.11 0.13 0.16 0.12 0.14 2.22
max 10.55 11.85 15.22 22.37 29.82 33.64 38.33 49.91 52.85 53.50 max 0.15 0.35 0.32 0.32 0.57 22.20
min 0.11 0.11 0.16 0.72 2.91 8.22 17.32 31.51 37.89 34.05 min 0.08 0.10 0.10 0.08 0.09 0.15
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 0.22 0.23 0.22 0.31 1.62 0.15 0.16 1.20 0.29 JAN 0.15 0.13 0.21 0.15 0.15 0.22 JAN 0.25 0.16 0.21 0.25 6.40
FEB 0.19 0.22 0.21 0.53 2.77 0.14 0.15 0.87 0.28 FEB 0.14 0.11 0.19 0.13 0.16 0.22 FEB 0.21 0.13 0.16 0.26 14.45
MAR 0.16 0.15 0.15 0.18 0.45 0.13 0.12 0.29 0.21 MAR 0.13 0.10 0.13 0.11 0.16 0.17 MAR 0.15 0.10 0.13 0.17 1.53
APR 0.11 0.13 0.12 0.27 0.43 0.11 0.09 0.24 0.17 APR 0.03 0.09 0.09 0.08 0.09 0.08 APR 0.10 0.07 0.09 0.13 0.53
MAY 0.09 0.10 0.16 0.32 4.90 0.10 0.11 0.38 0.21 MAY 0.11 0.08 0.11 0.08 0.11 0.16 MAY 0.13 0.08 0.08 0.14 4.16
JUN 0.15 0.30 0.22 0.61 8.81 0.17 0.14 1.09 0.32 JUN 0.14 0.09 0.17 0.14 0.11 0.22 JUN 0.16 0.09 0.06 0.14 11.24
JUL 0.18 0.38 0.22 0.63 13.91 0.29 0.33 1.13 0.60 JUL 0.15 0.10 0.33 0.06 0.10 0.23 JUL 0.39 0.14 0.00 0.18 24.48
AUG 0.16 0.40 0.22 0.65 4.99 0.16 0.14 0.35 0.20 AUG 0.13 0.09 0.18 0.07 0.10 0.16 AUG 0.30 0.11 0.11 0.19 13.43
SEP 0.22 0.53 0.62 0.80 8.03 0.29 0.11 0.59 0.24 SEP 0.09 0.06 0.08 0.07 0.08 0.09 SEP 0.18 0.08 0.10 0.16 3.44
OCT 0.14 0.19 0.19 0.34 1.95 0.13 0.12 0.57 0.27 OCT 0.12 0.08 0.10 0.07 0.10 0.15 OCT 0.17 0.08 0.08 0.12 4.23
NOV 0.18 0.21 0.22 0.27 1.39 0.15 0.16 0.45 0.28 NOV 0.13 0.09 0.15 0.08 0.12 0.18 NOV 0.20 0.10 0.08 0.13 3.61
DEC 0.19 0.19 0.18 0.33 1.27 0.14 0.15 0.40 0.25 DEC 0.13 0.09 0.12 0.09 0.11 0.17 DEC 0.19 0.09 0.08 0.13 1.78
mean 0.16 0.25 0.23 0.44 4.21 0.16 0.15 0.63 0.28 mean 0.12 0.09 0.15 0.09 0.11 0.17 mean 0.20 0.10 0.10 0.17 7.44
std dev 0.04 0.13 0.13 0.20 4.15 0.06 0.06 0.35 0.11 std dev 0.03 0.02 0.07 0.03 0.03 0.05 std dev 0.08 0.03 0.05 0.05 7.12
median 0.17 0.22 0.21 0.33 2.36 0.15 0.14 0.51 0.26 median 0.13 0.09 0.14 0.08 0.11 0.17 median 0.19 0.09 0.09 0.15 4.20
max 0.22 0.53 0.62 0.80 13.91 0.29 0.33 1.20 0.60 max 0.15 0.13 0.33 0.15 0.16 0.23 max 0.39 0.16 0.21 0.26 24.48
min 0.09 0.10 0.12 0.18 0.43 0.10 0.09 0.24 0.17 min 0.03 0.06 0.08 0.06 0.08 0.08 min 0.10 0.07 0.00 0.12 0.53
29
Table 2.4 pH during 2008 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 7.3 7.3 7.5 7.6 7.7 7.8 8.0 8.1 8.1 8.0 JAN 7.0 6.9 6.8 6.8 6.9 7.0
FEB 7.2 7.3 7.3 7.4 7.6 7.7 8.0 8.1 8.1 8.0 FEB 6.9 6.7 7.0 6.4 6.6 6.8
MAR 6.7 6.6 6.9 6.9 7.3 7.5 7.8 8.1 8.1 8.1 MAR 6.6 7.2 6.9 6.1 6.5 6.6
APR 6.8 7.2 7.0 7.0 7.2 7.4 7.7 8.0 8.1 7.9 APR 6.7 6.7 6.8 5.9 6.3 6.3
MAY 6.8 6.9 7.1 7.1 7.4 7.6 7.7 7.9 7.9 7.8 MAY 6.6 6.7 6.6 6.5 6.6 6.7
JUN 7.0 7.1 7.1 7.4 7.7 7.9 8.0 8.0 8.0 7.7 JUN 7.0 7.0 6.9 6.8 6.9 7.0
JUL 7.1 7.3 7.2 7.4 7.6 7.7 7.8 7.9 8.0 7.8 JUL 6.8 7.0 6.9 6.9 7.0 7.2
AUG 7.0 7.0 7.2 7.3 7.5 7.9 8.0 8.0 8.0 8.0 AUG 6.8 6.9 6.6 6.6 6.7 7.0
SEP 7.2 7.4 7.1 7.1 7.3 7.7 8.1 8.0 8.0 8.0 SEP 6.7 6.6 6.7 6.2 6.6 6.7
OCT 6.7 6.9 6.9 6.9 7.1 7.4 7.6 7.9 8.1 7.9 OCT 6.6 6.6 6.4 6.2 6.4 6.6
NOV 7.5 7.4 7.4 7.4 7.5 7.6 7.7 7.9 7.9 7.6 NOV 6.5 6.7 6.8 6.6 6.7 6.7
DEC 7.0 6.9 7.4 7.4 7.4 7.6 7.7 7.9 7.9 7.7 DEC 6.6 6.5 6.6 6.5 6.4 6.7
median 7.0 7.2 7.2 7.4 7.2 7.7 7.8 8.0 8.0 7.9 median 6.7 6.7 6.8 6.5 6.6 6.7
std dev 0.2 0.3 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.2 std dev 0.2 0.2 0.2 0.3 0.2 0.2
median 7.0 7.2 7.2 7.4 7.5 7.7 7.8 8.0 8.0 7.9 median 6.7 6.7 6.7 6.8 6.5 6.6
max 7.5 7.4 7.5 7.6 7.7 7.9 8.1 8.1 8.1 8.1 max 7.0 7.2 7.0 6.9 7.0 7.2
min 6.7 6.6 6.9 6.9 7.1 7.4 7.6 7.9 7.9 7.6 min 6.5 6.5 6.4 5.9 6.3 6.3
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 7.0 6.5 6.9 6.6 6.7 7.4 7.1 7.6 7.2 JAN 7.2 6.4 6.5 5.7 6.5 6.4 JAN 6.8 6.2 3.7 7.6 6.5
FEB 6.7 6.7 6.7 6.5 6.8 7.4 6.8 7.6 6.9 FEB 6.5 5.9 6.5 5.5 6.8 7.0 FEB 6.6 6.2 6.2 6.6 6.5
MAR 5.9 6.5 6.8 6.4 6.7 7.0 6.8 7.2 7.6 MAR 6.5 5.8 6.3 5.6 6.8 6.9 MAR 6.5 5.9 3.7 6.9 7.1
APR 5.6 6.4 6.5 6.3 6.5 6.6 6.3 7.0 6.5 APR 5.8 6.0 6.3 5.9 6.1 6.0 APR 6.2 5.7 4.1 6.7 6.6
MAY 5.4 5.8 6.8 6.5 7.1 7.0 6.9 7.3 7.0 MAY 6.9 6.4 6.5 6.0 6.9 6.9 MAY 6.5 6.1 4.0 6.8 6.7
JUN 6.7 7.1 6.7 6.5 7.4 8.1 7.1 7.9 7.0 JUN 7.2 6.9 7.2 6.0 7.1 6.7 JUN 6.6 6.5 4.1 6.7 7.0
JUL 7.1 7.0 7.0 7.0 8.0 8.1 7.3 7.9 7.5 JUL 7.1 6.7 7.1 6.0 6.9 7.0 JUL 7.0 6.9 6.6 7.1
AUG 6.7 7.3 7.1 6.4 6.9 7.7 7.1 7.3 6.9 AUG 7.0 6.4 6.4 6.1 6.8 6.7 AUG 6.7 6.0 3.8 6.8 6.9
SEP 6.9 6.2 5.2 6.3 7.1 7.4 6.8 7.6 6.9 SEP 5.9 5.2 6.0 5.9 5.9 6.1 SEP 6.6 5.6 3.8 6.5 6.7
OCT 5.9 6.2 6.2 6.3 6.7 7.3 6.9 7.3 6.5 OCT 6.4 6.1 6.1 5.9 6.5 6.7 OCT 6.2 5.8 3.8 6.3 6.7
NOV 6.4 6.3 6.4 6.6 6.6 7.3 6.9 7.2 6.6 NOV 7.4 6.6 6.5 5.9 6.6 7.0 NOV 6.3 5.8 4.0 7.1 6.8
DEC 6.5 6.5 6.6 6.6 6.6 7.2 7.0 7.0 6.4 DEC 6.5 6.0 6.2 5.9 6.4 6.7 DEC 6.7 6.2 3.9 6.4 6.5
median 6.6 6.5 6.7 6.5 6.8 7.4 6.9 7.3 6.9 median 6.7 6.3 6.5 5.9 6.7 6.7 median 6.6 6.1 3.9 6.7 6.7
std dev 0.6 0.4 0.5 0.2 0.4 0.4 0.2 0.3 0.4 std dev 0.5 0.5 0.4 0.2 0.4 0.3 std dev 0.2 0.4 0.7 0.3 0.2
median 6.6 6.5 6.7 6.5 6.8 7.4 6.9 7.3 6.9 median 6.7 6.3 6.5 5.9 6.7 6.7 median 6.6 6.1 3.9 6.7 6.7
max 7.1 7.3 7.1 7.0 8.0 8.1 7.3 7.9 7.6 max 7.4 6.9 7.2 6.1 7.1 7.0 max 7.0 6.9 6.2 7.6 7.1
min 5.4 5.8 5.2 6.3 6.5 6.6 6.3 7.0 6.4 min 5.8 5.2 6.0 5.5 5.9 6.0 min 6.2 5.6 3.7 6.3 6.5
30
Table 2.5 Dissolved Oxygen (mg/l) during 2008 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 9.3 9.4 9.4 9.2 9.4 9.5 9.5 9.5 9.3 9.4 JAN 10.7 10.1 9.9 10.0 9.9 9.1
FEB 9.3 9.2 9.2 8.9 9.2 9.3 9.4 9.4 9.4 8.8 FEB 10.4 9.8 9.7 9.2 9.2 9.3
MAR 8.6 8.5 8.4 8.4 8.8 8.9 9.0 9.0 8.8 9.0 MAR 10.8 10.3 10.2 9.4 9.8 9.3
APR 7.5 7.1 7.4 7.0 7.0 7.4 7.5 7.4 7.5 7.6 APR 8.8 8.5 8.2 6.4 7.0 5.6
MAY 6.2 6.1 6.4 6.3 6.5 6.9 6.9 6.9 7.0 6.7 MAY 7.2 6.7 5.7 5.5 5.9 6.0
JUN 4.9 5.4 5.5 6.2 7.4 7.8 7.1 6.8 6.1 5.1 JUN 8.8 6.8 5.1 5.1 5.4 6.8
JUL 3.9 4.3 4.8 5.8 6.1 6.2 6.1 5.9 6.1 5.7 JUL 6.8 5.1 3.5 3.5 3.8 5.6
AUG 3.5 3.8 4.9 4.8 5.4 7.0 7.9 5.6 5.8 6.0 AUG 6.4 6.0 4.6 4.6 4.5 3.6
SEP 4.8 5.0 6.0 4.9 5.1 7.2 8.9 6.6 6.5 6.8 SEP 6.7 6.4 6.1 4.3 5.7 4.1
OCT 4.7 4.9 4.8 4.9 5.1 5.8 5.7 6.3 6.4 6.2 OCT 7.8 7.4 5.0 4.6 4.8 4.3
NOV 7.2 7.0 7.0 6.9 7.3 7.6 7.6 7.8 7.9 7.1 NOV 9.5 9.1 9.1 7.7 8.4 7.3
DEC 9.8 9.8 9.6 8.9 9.0 9.1 9.0 8.9 8.6 8.6 DEC 10.3 9.9 9.6 9.2 8.9 8.9
mean 6.6 6.7 7.0 6.9 7.2 7.7 7.9 7.5 7.5 7.3 mean 8.7 8.0 7.2 6.6 6.9 6.7
std dev 2.3 2.1 1.8 1.7 1.6 1.2 1.3 1.4 1.3 1.4 std dev 1.7 1.8 2.5 2.3 2.2 2.1
median 6.7 6.6 6.7 6.6 7.2 7.5 7.8 7.2 7.3 7.0 median 8.8 8.8 8.0 7.2 6.0 6.5
max 9.8 9.8 9.6 9.2 9.4 9.5 9.5 9.5 9.4 9.4 max 10.8 10.3 10.2 10.0 9.9 9.3
min 3.5 3.8 4.8 4.8 5.1 5.8 5.7 5.6 5.8 5.1 min 6.4 5.1 3.5 3.5 3.8 3.6
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 6.1 7.1 8.7 6.8 8.4 10.7 9.2 7.3 3.7 JAN 11.6 11.5 9.7 8.9 11.1 10.3 JAN 8.9 10.1 8.4 7.5 9.4
FEB 11.7 6.6 8.3 5.2 8.3 10.8 8.3 6.8 3.6 FEB 11.2 10.8 8.4 9.0 11.7 9.5 FEB 10.2 9.4 8.5 8.0 9.5
MAR 9.9 7.1 9.5 8.1 8.6 10.5 8.8 9.5 6.0 MAR 9.4 9.3 6.8 6.8 9.8 9.2 MAR 9.1 8.5 7.2 9.9 8.7
APR 6.4 6.4 6.6 5.9 6.7 8.6 6.5 8.0 7.5 APR 6.1 6.3 5.7 4.8 7.2 8.5 APR 5.8 6.7 6.4 4.3 7.5
MAY 5.6 9.5 5.6 2.6 9.5 7.7 6.8 6.7 2.5 MAY 7.2 7.2 4.9 2.4 8.0 5.8 MAY 5.1 5.6 6.8 3.1 6.1
JUN 3.4 5.3 3.7 4.3 6.5 9.3 7.4 5.8 0.9 JUN 7.4 6.9 5.6 0.2 8.1 3.9 JUN 4.2 4.4 4.7 1.8 4.6
JUL 4.0 5.2 1.2 5.1 7.7 9.5 5.0 3.3 1.4 JUL 6.3 6.0 5.2 1.9 8.5 2.9 JUL 5.3 5.0 1.5 5.7
AUG 3.0 5.1 6.0 1.5 5.3 9.0 6.1 6.4 4.6 AUG 5.8 5.7 1.8 1.1 6.3 3.4 AUG 4.7 4.3 5.2 1.9 3.9
SEP 3.6 6.4 5.8 2.1 7.3 7.6 7.2 6.5 0.5 SEP 3.5 3.9 3.0 0.6 5.6 6.3 SEP 3.7 3.5 4.1 2.6 3.8
OCT 4.4 3.6 2.9 1.8 6.5 8.4 6.8 7.3 2.0 OCT 7.7 7.0 4.3 1.5 8.7 7.6 OCT 4.0 5.7 5.8 5.2 4.9
NOV 7.5 8.8 8.2 6.7 9.2 11.3 10.1 9.6 8.6 NOV 9.7 9.7 7.7 3.1 9.9 7.4 NOV 6.9 8.9 9.3 8.3 7.9
DEC 8.9 9.6 10.1 8.4 10.2 12.0 11.0 10.3 8.2 DEC 10.1 9.5 7.9 7.2 9.5 9.0 DEC 9.1 9.6 7.2 8.5 9.0
mean 6.2 6.7 6.4 4.9 7.9 9.6 7.8 7.3 4.1 mean 8.0 7.8 5.9 4.0 8.7 7.0 mean 6.4 6.8 6.7 5.2 6.8
std dev 2.8 1.8 2.8 2.4 1.4 1.4 1.7 1.9 2.9 std dev 2.4 2.3 2.3 3.2 1.8 2.5 std dev 2.3 2.4 1.7 3.1 2.2
median 5.9 6.5 6.3 5.2 8.0 9.4 7.3 7.1 3.7 median 7.6 7.1 5.7 2.8 8.6 7.5 median 5.6 6.2 6.8 4.8 6.8
max 11.7 9.6 10.1 8.4 10.2 12.0 11.0 10.3 8.6 max 11.6 11.5 9.7 9.0 11.7 10.3 max 10.2 10.1 9.3 9.9 9.5
min 3.0 3.6 1.2 1.5 5.3 7.6 5.0 3.3 0.5 min 3.5 3.9 1.8 0.2 5.6 2.9 min 3.7 3.5 4.1 1.5 3.8
31
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, 1995-2007 versus 2008.
1995-2007
2008
32
Table 2.6 Field Turbidity (NTU) during 2008 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 33 15 16 7 22 4 3 4 5 7 JAN 31 29 16 16 16 10
FEB FEB 12 12 13 4 7 35
MAR 76 62 75 62 43 21 9 9 12 10 MAR 10 12 12 3 7 10
APR 8 6 7 7 6 6 3 5 5 5 APR 20 17 18 4 12 11
MAY 10 13 11 6 5 5 4 5 6 8 MAY 14 13 11 8 7 5
JUN 37 10 9 6 9 7 5 3 3 7 JUN 7 17 10 9 9 8
JUL 16 12 11 8 8 6 5 3 1 5 JUL 11 15 14 13 18 7
AUG 13 8 9 7 6 7 5 3 3 4 AUG 11 9 8 8 7 15
SEP 13 16 14 8 7 6 4 3 3 3 SEP 33 42 19 9 13 12
OCT 7 6 7 5 6 3 3 3 3 5 OCT 12 9 7 7 7 14
NOV 48 7 6 8 8 7 8 8 10 6 NOV 12 17 9 6 10 30
DEC 16 14 11 9 8 6 7 9 11 8 DEC 143 110 87 62 39 18
mean 25 15 16 12 12 7 5 5 6 6 mean 26 25 19 12 13 15
std dev 22 16 20 17 11 5 2 2 4 2 std dev 38 28 22 16 9 9
median 16 12 11 7 8 6 5 4 5 6 median 12 12 16 13 8 10
max 76 62 75 62 43 21 9 9 12 10 max 143 110 87 62 39 35
min 7 6 6 5 5 3 3 3 1 3 min 7 9 7 3 7 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 0 0 0 1 6 3 6 10 36 JAN 7 5 5 4 5 4 JAN 5 2 1 3 33
FEB 5 2 2 1 6 2 3 11 13 FEB 5 4 1 1 3 5 FEB 5 1 0 2 11
MAR 2 5 2 11 50 6 12 16 16 MAR 4 2 1 0 3 3 MAR 1 0 0 0 9
APR 5 3 2 2 6 17 4 9 13 APR 18 4 3 2 18 13 APR 8 5 0 1 21
MAY 4 4 5 1 11 5 15 10 12 MAY 5 4 3 2 6 4 MAY 3 2 0 4 25
JUN 4 1 20 14 12 5 6 7 5 JUN 2 1 3 22 7 6 JUN 5 3 2 9 16
JUL 1 1 12 11 13 1 3 2 7 JUL 3 2 5 31 4 6 JUL 6 9 5 32
AUG 1 2 20 4 12 7 10 12 14 AUG 3 13 40 4 16 8 AUG 3 3 2 5 19
SEP 0 1 0 2 12 0 3 6 13 SEP 1 0 1 3 9 18 SEP 14 3 3 3 32
OCT 2 1 0 2 5 2 5 5 6 OCT 5 2 1 2 3 3 OCT 1 1 0 1 4
NOV 3 3 2 2 8 9 5 7 9 NOV 4 2 1 0 8 4 NOV 2 1 0 1 8
DEC 3 3 2 1 6 4 5 11 10 DEC 11 3 1 0 9 11 DEC 3 2 2 11 79
mean 3 2 6 4 12 5 6 9 13 mean 6 4 5 6 8 7 mean 5 3 1 4 24
std dev 2 1 7 5 12 5 4 4 8 std dev 5 3 11 10 5 5 std dev 4 2 1 3 20
median 3 2 2 2 10 5 5 10 13 median 5 3 2 2 6 6 median 4 2 0 3 20
max 5 5 20 14 50 17 15 16 36 max 18 13 40 31 18 18 max 14 9 3 11 79
min 0 0 0 1 5 0 3 2 5 min 1 0 1 0 3 3 min 1 0 0 0 4
33
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, 1995-2007 versus 2008.
1995-2007
2008
34
Table 2.7 Total Suspended Solids (mg/L) during 2008 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 23 18 15 8 10 6 4 6 8 20 JAN 10 9 9 11 11
FEB 18 14 19 13 15 15 13 16 29 24 FEB 10 9 10 4 41
MAR 31 34 29 35 30 20 13 18 22 17 MAR 9 9 10 7 16
APR 6 7 5 7 9 7 5 9 10 8 APR 17 15 16 13 13
MAY 12 9 11 9 10 9 9 7 16 24 MAY 7 4 1 5 6
JUN 42 15 14 17 17 21 7 10 7 9 JUN 5 7 6 5 6
JUL 12 11 10 10 16 9 9 7 5 10 JUL 8 11 11 20 18
AUG 18 8 4 9 9 9 9 8 17 16 AUG 6 6 7 5 22
SEP 10 8 12 9 9 11 18 9 10 10 SEP 29 24 10 7 26
OCT 9 8 6 6 8 6 7 20 8 8 OCT 9 5 5 4 8
NOV 8 11 16 16 15 17 18 24 26 20 NOV 12 15 8 10 40
DEC 10 9 8 9 8 10 11 12 15 14 DEC 96 77 47 14 24
mean 17 13 12 12 13 12 10 12 14 15 mean 18 16 12 9 19
std dev 11 8 7 8 6 5 5 6 8 6 std dev 25 20 12 5 12
median 12 10 12 9 10 10 9 10 13 15 median 10 10 9 10 7
max 42 34 29 35 30 21 18 24 29 24 max 96 77 47 20 41
min 6 7 4 6 8 6 4 6 5 8 min 5 4 1 4 6
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 3 3 3 2 5 3 8 6 27 JAN 3 3 1 2 2 3 JAN 5 2 1 1
FEB 5 3 5 1 6 2 2 8 10 FEB 4 3 2 1 1 5 FEB 6 1 1 1
MAR 2 6 3 5 16 6 18 14 11 MAR 5 3 1 5 2 2 MAR 3 1 1 1
APR 4 4 4 2 5 25 5 7 7 APR 7 3 1 3 25 11 APR 7 8 1 5
MAY 4 6 8 5 5 10 18 16 12 MAY 4 3 5 4 5 3 MAY 4 3 1 5
JUN 27 1 21 14 16 14 8 10 15 JUN 1 1 40 18 3 4 JUN 6 3 15 14
JUL 1 11 9 8 5 1 4 5 10 JUL 1 1 3 16 2 6 JUL 5 1 3
AUG 1 1 24 4 8 4 10 9 5 AUG 3 13 12 6 20 4 AUG 3 3 1 3
SEP 2 4 3 5 46 3 5 10 15 SEP 2 1 3 7 14 18 SEP 6 3 1 2
OCT 3 3 1 5 4 1 8 5 7 OCT 4 3 3 3 5 1 OCT 3 4 1 2
NOV 2 1 1 1 8 5 3 3 3 NOV 2 1 3 2 7 1 NOV 4 2 1 1
DEC 2 1 1 1 1 4 1 4 4 DEC 8 3 1 1 11 5 DEC 3 1 1 5
mean 5 4 7 4 10 7 8 8 11 mean 4 3 6 6 8 5 mean 5 3 2 4
std dev 7 3 8 4 12 7 6 4 7 std dev 2 3 11 6 8 5 std dev 1 2 4 4
median 3 3 4 5 6 4 7 8 10 median 4 3 3 4 5 4 median 5 3 1 3
max 27 11 24 14 46 25 18 16 27 max 8 13 40 18 25 18 max 7 8 15 14
min 1 1 1 1 1 1 1 3 3 min 1 1 1 1 1 1 min 3 1 1 1
35
Table 2.8 Light Attenuation during 2008 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 3.81 2.75 2.12 2.41 1.92 1.85 1.57 0.96 0.94 1.23 JAN 3.88 3.66 3.39 3.16 3.12 2.35
FEB 3.67 4.22 2.53 3.79 2.52 1.96 2.77 1.47 FEB 2.17 2.21 3.24 2.11 1.96 5.78
MAR 5.60 5.30 5.49 5.76 4.47 3.27 2.66 1.53 1.35 1.61 MAR 2.38 3.53 3.17 2.42 2.86 4.12
APR 2.79 3.32 2.83 3.16 2.47 2.24 2.02 1.71 1.26 1.71 APR 2.54 2.86 2.95 3.54 3.88 4.70
MAY 2.79 2.60 2.79 2.29 2.00 2.00 1.48 1.17 0.93 1.51 MAY 3.16 3.24 3.53 2.99 3.07 3.10
JUN 5.65 3.47 2.25 2.66 2.32 1.97 1.89 1.09 0.89 1.41 JUN 1.65 2.85 2.65 2.66 2.98 2.81
JUL 3.39 2.95 2.31 3.34 2.05 1.86 1.50 0.95 0.74 1.29 JUL 2.24 3.69 3.11 2.85 4.47 2.36
AUG 2.62 2.35 2.18 3.08 2.18 2.05 1.78 0.92 0.82 1.05 AUG 2.01 1.78 2.97 2.31 3.10 2.47
SEP 3.47 4.02 2.44 3.03 2.07 2.48 1.91 1.01 1.07 1.12 SEP 4.08 4.16 3.16 4.12 2.88 3.44
OCT 3.93 3.79 3.33 3.68 3.10 2.56 2.27 1.34 0.82 1.49 OCT 2.69 2.53 3.62 3.80 3.64 5.02
NOV 9.58 3.54 2.79 2.91 2.44 2.28 2.14 1.71 1.68 1.46 NOV 3.16 3.32 2.80 3.38 3.15 6.67
DEC 3.39 2.93 2.35 2.87 2.13 1.79 1.70 1.40 DEC 7.77 6.49 7.91 4.97 3.63 4.02
mean 4.22 3.44 2.78 3.25 2.47 2.26 1.92 1.35 1.25 1.40 mean 3.14 3.36 3.54 3.19 3.23 3.90
std dev 1.95 0.82 0.92 0.91 0.71 0.43 0.37 0.38 0.58 0.19 std dev 1.63 1.19 1.40 0.83 0.62 1.41
median 3.57 3.40 2.49 3.06 2.25 2.15 1.90 1.26 1.01 1.44 median 2.62 2.62 3.28 3.17 3.08 3.11
max 9.58 5.30 5.49 5.76 4.47 3.27 2.66 1.96 2.77 1.71 max 7.77 6.49 7.91 4.97 4.47 6.67
min 2.62 2.35 2.12 2.29 1.92 1.85 1.48 0.92 0.74 1.05 min 1.65 1.78 2.65 2.11 1.96 2.35
36
Table 2.9 Total Nitrogen (µg/l) during 2008 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 1,210 860 1,210 1,130 670 740 650 450 120 260 JAN 1,380 2,060 1,360 1,240 830
FEB 1,370 1,130 1,370 1,070 1,260 1,220 550 720 200 470 FEB 1,760 1,620 1,680 1,310 1,300
MAR 2,180 1,850 1,820 1,550 1,430 1,340 1,130 200 270 620 MAR 2,470 2,390 1,640 1,210 1,480
APR 1,280 1,550 1,610 750 900 660 730 360 200 350 APR 1,200 1,040 1,170 1,400 1,440
MAY 1,190 1,320 1,140 1,190 970 830 720 110 50 70 MAY 1,090 1,450 900 700 700
JUN 1,200 1,200 900 1,000 870 530 390 160 150 600 JUN 1,330 1,800 1,350 1,230 810
JUL 1,580 1,550 1,270 1,200 910 6,720 480 200 200 200 JUL 2,050 2,110 2,560 2,350 830
AUG 1,240 1,290 1,090 1,170 1,130 780 700 500 300 700 AUG 1,320 1,580 1,390 1,550 950
SEP 1,040 930 980 950 1,050 900 1,210 260 200 260 SEP 1,410 1,090 1,390 970 960
OCT 890 1,060 1,090 1,100 910 670 570 360 1,920 350 OCT 1,340 980 1,350 2,130 550
NOV 1,670 790 910 1,140 880 750 360 740 580 430 NOV 1,400 1,490 1,530 1,610 1,090
DEC 850 890 960 880 980 680 640 540 260 290 DEC 1,700 1,550 1,910 1,180 1,040
mean 1,308 1,202 1,196 1,094 997 1,318 678 383 371 383 mean 1,538 1,597 1,519 1,407 998
std dev 350 312 273 190 191 1,644 249 202 483 179 std dev 378 421 398 440 276
median 1,225 1,165 1,115 1,115 940 765 645 360 200 350 median 1,470 1,565 1,390 1,275 955
max 2,180 1,850 1,820 1,550 1,430 6,720 1,210 740 1,920 700 max 2,470 2,390 2,560 2,350 1,480
min 850 790 900 750 670 530 360 110 50 70 min 1,090 980 900 700 550
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 400 570 100 1,430 1,930 550 1,140 25,300 1,180 JAN 1,070 1,150 980 540 470 550 JAN 850 710 520 1,150
FEB 2,260 960 850 1,160 1,420 450 930 17,800 990 FEB 950 1,010 1,240 1,030 540 740 FEB 1,250 760 630 1,890
MAR 9,730 1,250 130 2,170 2,940 950 1,430 5,010 1,020 MAR 1,330 1,730 1,030 960 850 750 MAR 710 1,020 900 1,390
APR 2,260 1,280 1,240 1,700 2,220 2,050 1,870 3,300 1,240 APR 2,820 910 1,660 1,900 1,250 1,720 APR 1,050 950 1,200 900
MAY 1,560 1,340 1,190 1,190 1,000 900 1,920 6,740 1,830 MAY 1,700 1,230 940 970 710 580 MAY 1,150 1,150 960 1,200
JUN 1,290 2,960 1,730 1,500 1,190 660 1,730 27,300 2,010 JUN 940 910 1,640 1,840 770 440 JUN 1,030 890 1,040 1,870
JUL 830 890 1,930 1,070 1,300 400 2,350 24,000 1,510 JUL 380 870 1,180 1,130 720 230 JUL 960 670 4,180
AUG 970 3,450 2,330 940 1,140 720 2,420 4,920 590 AUG 1,050 1,930 2,640 1,130 1,180 850 AUG 660 960 830 2,500
SEP 800 1,590 1,600 1,100 3,580 600 1,740 12,300 1,200 SEP 1,190 1,170 1,030 1,260 850 1,270 SEP 750 1,020 1,240 1,220
OCT 1,440 1,050 1,020 1,080 690 1,010 970 9,470 680 OCT 1,590 1,060 530 660 550 510 OCT 1,200 1,210 1,040 1,220
NOV 1,770 630 500 2,230 3,360 1,200 1,660 8,100 900 NOV 1,560 940 930 460 680 300 NOV 1,100 670 600 760
DEC 1,640 760 500 1,640 2,380 830 1,360 6,440 790 DEC 1,890 1,230 720 800 910 1,330 DEC 770 620 600 1,330
mean 2,079 1,394 1,093 1,434 1,929 860 1,627 12,557 1,162 mean 1,373 1,178 1,210 1,057 790 773 mean 957 886 869 1,634
std dev 2,371 865 683 412 927 425 464 8,366 419 std dev 587 318 533 432 229 433 std dev 195 190 241 893
median 1,500 1,150 1,105 1,310 1,675 775 1,695 8,785 1,100 median 1,260 1,105 1,030 1,000 745 660 median 995 920 900 1,275
max 9,730 3,450 2,330 2,230 3,580 2,050 2,420 27,300 2,010 max 2,820 1,930 2,640 1,900 1,250 1,720 max 1,250 1,210 1,240 4,180
min 400 570 100 940 690 400 930 3,300 590 min 380 870 530 460 470 230 min 660 620 520 760
37
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, 1995-2007 versus 2008.
1995-2007
2008
38
Table 2.10 Nitrate/Nitrite (µg/l) during 2008 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 610 460 510 530 470 440 350 250 120 160 JAN 880 1,060 760 640 430
FEB 670 630 570 470 460 420 350 220 100 70 FEB 1,060 1,020 980 710 400
MAR 480 450 520 450 430 340 230 10 70 120 MAR 770 790 740 510 480
APR 380 350 410 250 200 160 130 60 10 50 APR 500 440 470 300 240
MAY 550 550 550 470 420 340 270 110 10 70 MAY 390 650 100 100 10
JUN 460 390 360 330 280 180 60 10 10 10 JUN 750 810 560 520 340
JUL 880 850 770 500 310 520 80 10 10 10 JUL 850 810 960 1,150 430
AUG 640 590 590 470 330 180 100 10 10 10 AUG 820 880 490 650 350
SEP 440 530 480 550 550 400 210 60 10 60 SEP 610 590 690 470 460
OCT 390 360 390 300 210 170 170 60 1720 50 OCT 640 680 450 1,730 150
NOV 770 790 710 640 580 550 360 140 80 30 NOV 900 790 930 810 90
DEC 450 490 460 380 380 380 340 240 160 90 DEC 700 650 610 480 240
mean 560 537 527 445 385 340 221 98 193 61 mean 739 764 645 673 302
std dev 150 152 118 107 118 132 108 89 463 44 std dev 177 168 244 404 148
median 515 510 515 470 400 360 220 60 40 55 median 715 650 580 345 345
max 880 850 770 640 580 550 360 250 1,720 160 max 1,060 1,060 980 1,730 480
min 380 350 360 250 200 160 60 10 10 10 min 390 440 100 100 10
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 10 70 10 730 1,530 50 340 24,900 380 JAN 870 450 180 40 170 50 JAN 350 310 20 450
FEB 160 160 50 460 420 50 530 16,900 190 FEB 550 410 340 30 40 40 FEB 350 260 30 290
MAR 530 250 30 1,070 1,740 150 430 4,010 220 MAR 1,030 930 130 60 250 150 MAR 510 320 10 290
APR 460 180 140 700 1,220 450 370 2,100 140 APR 720 210 60 10 150 220 APR 350 250 10 10
MAY 60 240 190 290 10 10 820 5,340 730 MAY 910 400 100 50 290 110 MAY 350 450 360 10
JUN 30 1,520 10 10 10 10 730 27,300 90 JUN 340 210 340 40 370 40 JUN 240 200 30 890
JUL 30 90 30 70 10 10 1,350 24,000 110 JUL 80 70 180 30 420 30 JUL 260 70 980
AUG 70 1,550 30 40 40 120 1,020 3,420 190 AUG 350 130 40 30 80 150 AUG 160 160 30 1,100
SEP 10 390 10 10 980 10 440 11,200 10 SEP 190 70 30 60 50 370 SEP 150 120 40 220
OCT 40 50 20 80 90 110 170 9,270 80 OCT 590 160 30 60 150 110 OCT 200 110 40 220
NOV 270 30 10 1,530 2,460 200 860 7,700 500 NOV 960 440 330 160 180 10 NOV 200 170 10 60
DEC 440 260 10 1,240 1,780 130 660 5,840 390 DEC 1,190 730 320 300 310 330 DEC 270 220 10 230
mean 176 399 45 519 858 108 643 11,832 253 mean 648 351 173 73 205 134 mean 283 220 54 396
std dev 188 518 56 510 837 120 319 8,720 200 std dev 340 256 123 77 118 113 std dev 99 102 98 366
median 65 210 25 375 700 80 595 8,485 190 median 655 305 155 45 175 110 median 265 210 30 260max5301,550 190 1,530 2,460 450 1,350 27,300 730 max 1,190 930 340 300 420 370 max 510 450 360 1,100
min 10 30 10 10 10 10 170 2,100 10 min 80 70 30 10 40 10 min 150 70 10 10
39
Table 2.11 Ammonium (µg/l) during 2008 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 100 120 180 130 140 120 50 30 5 10 JAN 50 80 50 50 130
FEB 60 60 70 120 100 110 80 10 5 5 FEB 20 70 90 60 50
MAR 100 90 110 110 130 60 40 40 5 30 MAR 40 190 100 40 20
APR 50 50 50 60 80 70 60 30 5 20 APR 50 80 80 50 30
MAY 70 70 70 90 90 50 80 20 5 20 MAY 100 150 130 90 80
JUN 90 110 110 130 190 50 20 30 5 50 JUN 40 180 190 110 50
JUL 30 30 30 40 40 40 10 5 5 5 JUL 70 340 60 20 20
AUG 40 5 30 20 30 20 5 5 5 10 AUG 100 110 80 70 30
SEP 70 50 50 30 30 5 5 5 5 5 SEP 70 100 100 40 30
OCT 80 60 70 70 100 50 60 10 5 10 OCT 40 50 50 50 30
NOV 60 180 230 250 190 120 120 20 5 NOV 40 50 60 50 20
DEC 20 30 40 100 100 110 100 70 10 30 DEC 70 50 70 50 30
mean 64 71 87 96 102 67 53 23 5 18 mean 58 121 88 57 43
std dev 26 48 62 62 54 39 38 19 1 14 std dev 25 85 40 24 32
median 65 60 70 95 100 55 55 20 5 10 median 60 50 30 50 30
max 100 180 230 250 190 120 120 70 10 50 max 100 340 190 110 130
min 20 5 30 20 30 5 5 5 5 5 min 20 50 50 20 20
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 20 10 10 20 80 20 340 60 60 JAN 70 30 20 5 30 5 JAN 30 10 10 590
FEB 5 20 10 40 130 10 40 40 30 FEB 40 20 20 10 20 5 FEB 50 5 5 1,070
MAR 10 10 5 10 380 10 30 180 40 MAR 20 20 10 10 30 20 MAR 20 5 40 310
APR 80 50 50 40 120 170 70 90 110 APR 80 30 50 20 30 70 APR 60 50 5 270
MAY 230 130 120 130 20 50 70 110 120 MAY 60 60 30 60 40 50 MAY 50 30 30 750
JUN 170 200 210 190 40 80 90 180 710 JUN 70 70 90 450 140 170 JUN 80 100 120 390
JUL 40 70 460 140 20 20 40 40 260 JUL 30 30 60 100 20 30 JUL 10 30 1,810
AUG 20 80 520 30 40 190 60 80 70 AUG 50 50 70 50 40 60 AUG 5 20 50 1,300
SEP 5 5 20 110 650 40 40 70 290 SEP 10 5 10 40 5 50 SEP 20 5 30 390
OCT 60 40 40 70 120 70 40 50 80 OCT 70 20 40 70 20 30 OCT 50 20 20 210
NOV 210 20 10 40 110 20 30 40 30 NOV 30 10 40 10 5 5 NOV 50 10 10 230
DEC 80 90 5 10 70 80 30 60 5 DEC 60 30 30 20 10 510 DEC 20 10 5 790
mean 78 60 122 69 148 63 73 83 150 mean 49 31 39 70 33 84 mean 37 25 30 676
std dev 81 58 183 59 185 60 86 50 198 std dev 23 20 25 123 36 142 std dev 23 27 34 499
median 50 45 30 40 95 45 40 65 75 median 55 30 35 30 25 40 median 40 15 20 490
max 230 200 520 190 650 190 340 180 710 max 80 70 90 450 140 510 max 80 100 120 1,810
min 5 5 5 10 20 10 30 40 5 min 10 5 10 5 5 5 min 5 5 5 210
40
Table 2.12 Total Kjeldahl Nitrogen (µg/l) during 2008 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 600 400 700 600 200 300 300 200 50 100 JAN 500 1,000 600 600 400
FEB 700 500 800 600 800 800 200 500 100 400 FEB 700 600 700 600 900
MAR 1,700 1,400 1,300 1,100 1,000 1,000 900 200 200 500 MAR 1,700 1,600 900 700 1,000
APR 900 1,200 1,200 500 700 500 600 300 200 300 APR 700 600 700 1,100 1,200
MAY 640 770 590 720 550 490 450 50 50 50 MAY 700 800 800 600 700
JUN 740 810 540 670 590 350 330 160 150 600 JUN 580 990 790 710 470
JUL 700 700 500 700 600 6,200 400 200 200 200 JUL 1,200 1,300 1,600 1,200 400
AUG 600 700 500 700 800 600 600 500 300 700 AUG 500 700 900 900 600
SEP 600 400 500 400 500 500 1,000 200 200 200 SEP 800 500 700 500 500
OCT 500 700 700 800 700 500 400 300 200 300 OCT 700 300 900 400 400
NOV 900 50 200 500 300 200 50 600 500 400 NOV 500 700 600 800 1,000
DEC 400 400 500 500 600 300 300 300 100 200 DEC 1,000 900 1,300 700 800
mean 748 669 669 649 612 978 461 293 188 329 mean 798 833 874 734 734
std dev 318 351 297 176 208 1,589 264 156 117 190 std dev 338 342 283 225 225
median 670 700 565 635 600 500 400 250 200 300 median 705 700 650 700 650
max 1,700 1,400 1,300 1,100 1,000 6,200 1,000 600 500 700 max 1,700 1,600 1,600 1,200 1,200
min 400 50 200 400 200 200 50 50 50 50 min 500 300 600 400 400
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 400 500 100 700 400 500 800 400 800 JAN 200 700 800 500 300 500 JAN 500 400 500 700
FEB 2,100 800 800 700 1,000 400 400 900 800 FEB 400 600 900 1,000 500 700 FEB 900 500 600 1,600
MAR 9,200 1,000 100 1,100 1,200 800 1,000 1,000 800 MAR 300 800 900 900 600 600 MAR 200 700 900 1,100
APR 1,800 1,100 1,100 1,000 1,000 1,600 1,500 1,200 1,100 APR 2,100 700 1,600 1,900 1,100 1,500 APR 700 700 1,200 900
MAY 1,500 1,100 1,000 900 1,000 900 1,100 1,400 1,100 MAY 790 830 840 920 420 470 MAY 800 700 600 1,200
JUN 1,260 1,440 1,730 1,500 1,190 660 1,000 50 1,920 JUN 600 700 1,300 1,800 400 400 JUN 790 690 1,010 980
JUL 800 800 1,900 1,000 1,300 400 1,000 50 1,400 JUL 300 800 1,000 1,100 300 200 JUL 700 600 3,200
AUG 900 1,900 2,300 900 1,100 600 1,400 1,500 400 AUG 700 1,800 2,600 1,100 1,100 700 AUG 500 800 800 1,400
SEP 800 1,200 1,600 1,100 2,600 600 1,300 1,100 1,200 SEP 1,000 1,100 1,000 1,200 800 900 SEP 600 900 1,200 1,000
OCT 1,400 1,000 1,000 1,000 600 900 800 200 600 OCT 1,000 900 500 600 400 400 OCT 1,000 1,100 1,000 1,000
NOV 1,500 600 500 700 900 1,000 800 400 400 NOV 600 500 600 300 500 300 NOV 900 500 600 700
DEC 1,200 500 500 400 600 700 700 600 400 DEC 700 500 400 500 600 1,000 DEC 500 400 600 1,100
mean 1,905 995 1,053 917 1,074 755 983 733 910 mean 724 828 1,037 985 585 639 mean 674 666 819 1,240
std dev 2,245 388 679 264 529 316 300 495 441 std dev 485 334 566 472 266 344 std dev 216 197 245 640
median 1,330 1,000 1,000 950 1,000 680 1,000 750 800 median 650 750 900 960 500 550 median 700 695 800 1,050
max 9,200 1,900 2,300 1,500 2,600 1,600 1,500 1,500 1,920 max 2,100 1,800 2,600 1,900 1,100 1,500 max 1,000 1,100 1,200 3,200
min 400 500 100 400 400 400 400 50 400 min 200 500 400 300 300 200 min 200 400 500 700
41
Table 2.13 Total Phosphorus (µg/l) during 2008 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 120 90 100 70 80 70 50 40 10 40 JAN 160 150 100 100 80
FEB 190 170 170 100 100 80 70 50 50 50 FEB 160 130 150 100 200
MAR 160 190 200 160 150 100 70 50 40 50 MAR 130 170 140 80 100
APR 110 90 100 80 80 70 60 40 40 40 APR 110 110 110 130 120
MAY 120 100 110 90 70 70 60 50 30 50 MAY 160 150 130 120 80
JUN 180 110 110 90 110 70 80 60 50 60 JUN 120 160 140 140 90
JUL 270 190 160 130 90 80 70 60 40 30 JUL 160 220 230 270 100
AUG 150 160 130 110 120 110 60 30 30 30 AUG 160 180 160 170 130
SEP 120 120 130 110 100 120 120 40 40 30 SEP 170 160 140 110 130
OCT 110 100 110 80 70 50 50 30 20 30 OCT 100 100 110 100 120
NOV 190 110 100 80 70 60 60 50 50 NOV 120 130 130 140 190
DEC 70 70 60 60 80 60 50 40 40 10 DEC 360 320 220 120 110
mean 149 125 123 97 93 78 67 45 37 38 mean 159 165 147 132 132
std dev 51 40 36 27 23 20 18 10 12 13 std dev 65 56 39 48 48
median 135 110 110 90 85 70 60 45 40 40 median 130 120 115 120 115
max 270 190 200 160 150 120 120 60 50 60 max 360 320 230 270 270
min 70 70 60 60 70 50 50 30 10 10 min 100 100 100 80 80
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 30 40 40 70 70 100 260 3,550 230 JAN 40 20 170 20 40 80 JAN 90 40 10 10
FEB 80 70 70 80 150 50 170 1,770 240 FEB 50 40 280 30 50 90 FEB 810 40 20 40
MAR 90 80 70 160 180 40 140 400 130 MAR 60 40 190 40 60 80 MAR 70 40 20 30
APR 230 100 100 130 130 150 130 250 130 APR 140 200 260 70 120 100 APR 160 80 30 40
MAY 160 160 170 220 140 100 250 730 170 MAY 110 70 390 90 100 180 MAY 110 100 20 50
JUN 150 330 400 490 220 80 380 3,400 370 JUN 130 110 1,160 210 120 200 JUN 120 130 50 80
JUL 100 150 510 380 230 70 380 3,860 400 JUL 150 120 660 160 80 210 JUL 90 130 70
AUG 50 880 370 330 230 60 650 680 160 AUG 150 130 1,720 90 260 230 AUG 80 140 70 60
SEP 40 110 90 500 370 70 360 1,670 350 SEP 130 60 200 110 160 170 SEP 170 130 90 50
OCT 230 180 170 320 170 40 250 1,340 180 OCT 130 70 80 60 100 160 OCT 140 110 10 20
NOV 170 90 80 70 180 70 150 790 70 NOV 80 30 150 40 80 150 NOV 90 60 10 10
DEC 140 60 60 50 80 40 110 470 60 DEC 80 30 50 10 80 110 DEC 40 10 10 30
mean 123 188 178 233 179 73 269 1,576 208 mean 104 77 443 78 104 147 mean 164 84 31 41
std dev 66 221 152 159 76 31 148 1,260 109 std dev 38 51 485 57 57 51 std dev 198 43 26 21
median 120 105 95 190 175 70 250 1,065 175 median 120 65 230 65 90 155 median 100 90 20 40
max 230 880 510 500 370 150 650 3,860 400 max 150 200 1,720 210 260 230 max 810 140 90 80
min 30 40 40 50 70 40 110 250 60 min 40 20 50 10 40 80 min 40 10 10 10
42
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, 1995-2007 versus 2008.
1995-2007
2008
43
Table 2.14 Orthophosphate (µg/l) during 2008 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 BBT
JAN 30 20 40 40 50 40 30 30 0 20 JAN 80 70 30 30 30 30
FEB 90 80 70 50 40 40 30 10 10 10 FEB 60 70 60 30 50 30
MAR 60 60 80 60 40 40 30 10 10 20 MAR 70 90 70 20 40 20
APR 40 30 30 40 30 30 20 10 10 20 APR 30 40 40 30 40 30
MAY 50 50 50 50 50 40 40 40 30 30 MAY 70 70 60 50 50 40
JUN 30 30 20 30 20 20 10 10 10 20 JUN 40 70 50 50 30 40
JUL 60 60 50 40 30 20 20 10 10 20 JUL 40 60 70 70 30 50
AUG 70 80 70 60 40 20 10 10 0 10 AUG 80 100 80 100 60 70
SEP 50 50 50 40 50 40 30 10 0 10 SEP 50 50 50 50 40 40
OCT 40 40 40 40 30 30 20 10 10 10 OCT 40 50 40 30 50 40
NOV 70 60 40 40 40 40 30 20 10 10 NOV 60 50 60 80 50 30
DEC 20 30 30 30 30 30 30 20 20 10 DEC 80 80 70 40 30 50
mean 51 49 48 43 38 33 25 16 10 16 mean 58 67 57 48 42 39
std dev 19 19 17 9 9 8 9 10 8 6 std dev 17 17 14 23 10 13
median 50 50 45 40 40 35 30 10 10 15 median 50 45 40 45 40 40
max 90 80 80 60 50 40 40 40 30 30 max 80 100 80 100 60 70
min 20 20 20 30 20 20 10 10 0 10 min 30 40 30 20 30 20
month ANC SAR GS NC403 PB LRC ROC BC117 BCRR month 6RC LCO GCO SR BRN HAM month NCF117 B210 COL LVC2
JAN 10 10 10 30 10 20 140 430 50 JAN 10 10 120 0 10 20 JAN 30 20 0 0
FEB 10 20 20 40 30 10 120 1770 120 FEB 20 10 250 0 20 20 FEB 30 20 0 10
MAR 20 20 10 80 30 10 40 360 50 MAR 10 10 190 0 20 30 MAR 20 10 0 10
APR 120 20 20 40 20 20 40 1730 30 APR 40 80 120 10 20 20 APR 70 30 0 0
MAY 100 20 20 40 30 10 60 550 50 MAY 30 20 220 10 20 40 MAY 30 30 0 0
JUN 60 60 40 60 40 40 130 1770 60 JUN 50 40 60 40 50 60 JUN 50 60 30 40
JUL 30 40 30 50 20 20 200 2820 90 JUL 50 40 300 20 20 60 JUL 20 40 10
AUG 10 40 20 110 30 20 300 450 60 AUG 40 20 10 40 70 AUG 20 50 40 10
SEP 0 20 20 130 10 10 150 1170 60 SEP 60 10 100 20 70 60 SEP 60 50 50 0
OCT 130 50 60 120 50 10 100 830 40 OCT 30 10 40 10 40 50 OCT 60 30 0 0
NOV NOV 20 10 80 10 20 60 NOV 30 20 0 0
DEC 90 20 10 30 20 0 50 310 20 DEC 20 10 30 0 20 30 DEC 20 10 0 0
mean 53 29 24 66 26 15 121 1,108 57 mean 32 23 137 11 29 43 mean 37 31 11 7
std dev 47 15 14 36 11 10 75 779 26 std dev 16 20 86 11 17 18 std dev 17 16 18 11
median 30 20 20 50 30 10 120 830 50 median 30 10 120 10 20 45 median 30 30 0 0
max 130 60 60 130 50 40 300 2,820 120 max 60 80 300 40 70 70 max 70 60 50 40
min 0 10 10 30 10 0 40 310 20 min 10 10 30 0 10 20 min 20 10 0 0
44
Table 2.15 Chlorophyll a (µg/l) during 2008 at the Lower Cape Fear River Program stations.
month NAV HB BRR M61 M54 M42 M35 M23 M18 SPD month NC11 AC DP BBT IC NCF6
JAN 2.8 3.1 4.5 2.7 2.8 3.9 4.1 1.0 4.5 5.3 JAN 1.2 1.1 1.3 1.4 1.9 2.7
FEB 3.5 3.1 4.0 3.7 6.2 6.6 7.0 10.8 12.2 7.0 FEB 3.5 3.4 2.8 1.2 1.5 3.4
MAR 4.4 3.7 3.7 4.0 5.2 6.8 4.2 6.5 5.7 5.2 MAR 2.5 1.6 1.6 1.0 1.4 2.2
APR 5.7 3.8 5.1 3.3 2.5 2.5 4.5 3.5 4.5 4.1 APR 2.7 2.8 2.8 1.0 1.4 1.4
MAY 3.3 3.3 6.8 4.8 3.4 5.2 3.8 3.4 5.0 3.9 MAY 2.0 1.2 1.1 1.0 1.2 1.5
JUN 8.8 10.1 16.1 19.3 23.9 25.2 29.5 13.0 8.5 6.8 JUN 12.8 4.9 3.0 3.1 6.3 9.6
JUL 9.4 9.0 11.4 21.4 26.7 21.4 15.9 4.9 5.7 9.4 JUL 24.1 11.1 4.4 3.1 3.9 12.0
AUG 8.8 7.8 24.5 18.6 24.0 39.8 23.7 9.0 8.3 9.5 AUG 34.2 22.9 14.7 11.7 13.4 31.7
SEP 3.0 5.0 9.0 7.0 11.0 35.0 40.0 13.0 11.0 16.0 SEP 2.0 2.0 2.0 1.0 1.0 5.0
OCT 1.0 1.0 1.0 1.0 2.0 3.0 3.0 4.0 2.0 3.0 OCT 1.0 0.5 1.0 1.0 1.0 1.0
NOV 3.4 1.4 2.7 2.4 2.4 2.7 3.1 4.9 4.3 3.3 NOV 1.1 1.1 1.2 0.9 0.6 1.5
DEC 1.0 1.0 1.1 1.2 1.3 1.8 1.8 3.3 3.6 2.9 DEC 5.0 4.3 3.2 2.7 1.7 1.5
mean 4.6 4.4 7.5 7.5 9.3 12.8 11.7 6.4 6.3 6.4 mean 7.7 4.7 3.3 2.4 2.9 6.1
std dev 2.8 2.9 6.6 7.3 9.4 13.2 12.2 3.9 2.9 3.6 std dev 10.3 6.1 3.6 2.9 3.5 8.4
median 3.5 3.5 4.8 3.9 4.3 5.9 4.4 4.9 5.4 5.3 median 2.6 2.6 2.4 2.4 1.1 1.5
max 9.4 10.1 24.5 21.4 26.7 39.8 40.0 13.0 12.2 16.0 max 34.2 22.9 14.7 11.7 13.4 31.7
min 1.0 1.0 1.0 1.0 1.3 1.8 1.8 1.0 2.0 2.9 min 1.0 0.5 1.0 0.9 0.6 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 3.8 1.2 2.6 6.5 8.8 5.7 0.8 0.8 6.7 JAN 0.8 0.7 1.8 2.0 1.5 2.6 JAN 0.5 0.4 0.7 1.2
FEB 84.3 2.1 7.2 3.1 8.0 2.8 0.9 1.8 7.7 FEB 3.1 1.3 1.6 3.4 3.1 32.4 FEB 0.9 1.3 1.2 2.9
MAR 17.1 3.5 2.5 8.4 4.6 4.1 2.4 9.9 1.5 MAR 1.2 1.0 1.6 1.2 1.5 3.8 MAR 1.1 1.4 1.1 1.0
APR 2.2 1.7 2.2 1.7 2.3 2.6 1.0 2.7 1.1 APR 2.0 2.2 3.3 5.6 3.4 1.9 APR 0.9 1.2 3.3 3.8
MAY 2.7 1.5 2.4 5.2 12.0 14.3 2.8 4.6 1.3 MAY 0.7 0.7 1.1 2.3 0.9 0.5 MAY 0.5 0.5 0.8 1.6
JUN 19.4 1.4 118.3 100.9 43.0 2.3 0.9 3.7 376.0 JUN 3.3 0.7 1.6 104.1 1.5 1.6 JUN 1.3 1.2 6.7 4.4
JUL 11.4 7.2 36.1 39.6 79.9 12.5 24.0 5.8 113.8 JUL 0.9 1.2 1.2 14.3 8.1 7.3 JUL 4.3 2.2 7.7
AUG 81.5 58.7 281.4 56.3 173.3 7.0 16.3 14.4 14.6 AUG 5.8 12.6 42.9 22.0 32.0 40.3 AUG 32.1 6.4 18.9 27.6
SEP 15.0 3.0 3.0 12.0 163.0 9.0 1.0 7.0 4.0 SEP 1.0 0.0 1.0 3.0 1.0 2.0 SEP 2.0 0.0 1.0 6.0
OCT 4.0 2.0 2.0 8.0 4.0 2.0 1.0 3.0 1.0 OCT 1.0 0.5 1.0 2.0 1.0 1.0 OCT 1.0 1.0 1.0 1.0
NOV 1.2 0.5 0.6 1.3 1.1 59.3 0.7 0.7 0.2 NOV 0.4 0.4 1.7 1.3 1.1 0.5 NOV 0.3 0.7 0.2 0.3
DEC 0.8 0.5 1.0 1.9 2.3 30.4 1.4 1.0 0.5 DEC 1.3 0.8 1.4 2.3 1.5 1.5 DEC 0.2 0.4 0.3 2.3
mean 20.3 6.9 38.3 20.4 41.9 12.7 4.4 4.6 44.0 mean 1.8 1.8 5.0 13.6 4.7 8.0 mean 3.8 1.4 3.2 5.0
std dev 28.7 15.7 80.1 29.3 60.7 16.0 7.2 4.0 104.6 std dev 1.5 3.3 11.4 27.9 8.5 12.9 std dev 8.6 1.6 5.3 7.1
median 7.7 1.9 2.6 7.3 8.4 6.4 1.0 3.4 2.8 median 1.1 0.8 1.6 2.7 1.5 2.0 median 1.0 1.1 1.0 2.6
max 84.3 58.7 281.4 100.9 173.3 59.3 24.0 14.4 376.0 max 5.8 12.6 42.9 104.1 32.0 40.3 max 32.1 6.4 18.9 27.6
min 0.8 0.5 0.6 1.3 1.1 2.0 0.7 0.7 0.2 min 0.4 0.0 1.0 1.2 0.9 0.5 min 0.2 0.0 0.2 0.3
45
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-
2007 versus 2008.
1995-2007
2008
46
Table 2.16 Biochemical Oxygen Demand (mg/l) during 2008 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 1.2 1.2 1.4 0.8 0.6 0.7 0.8 1.0 1.0 1.0 1.2 1.1
FEB 4.9 0.6 0.8 0.6 0.5 0.9 0.4 0.2 1.0
MAR 0.8 1.8 2.0 1.3 0.8 1.2 1.7 1.8 1.3 0.9 2.2 1.1
APR 0.9 1.0 2.1 1.6 1.5 1.2 1.5 1.5 2.4 1.8 2.3 0.9
MAY 1.2 1.3 1.4 1.8 1.6 2.2 2.8 2.3 1.1 1.3 3.3 1.1JUN2.1 1.3 4.4 0.8 8.9 7.8 0.9 1.6 0.9 1.0 1.3 0.9
JUL 2.3 2.1 1.9 0.8 4.6 2.9 2.8 0.8 0.6 1.4 2.9
AUG 2.0 1.5 2.1 0.9 6.4 1.8 1.2 1.5 0.7 1.0 3.3 2.0
SEP 1.5 1.6 2.2 1.2 1.6 2.3 1.3 1.3 0.7 2.5 1.6 1.4
OCT 1.0 0.7 1.8 1.7 1.2 1.4 1.4 2.1 1.3 2.1 1.7 1.3
NOV
DEC 1.3 2.0 2.4 1.3 1.1 1.0
median 1.2 1.3 2.0 1.2 1.6 1.4 1.3 1.5 1.0 1.2 2.0 1.1
mean 1.4 1.4 2.3 1.2 2.8 2.1 1.5 1.4 1.0 1.3 2.1 1.2
max 2.3 2.1 4.9 2.0 8.9 7.8 2.8 2.3 2.4 2.5 3.3 2.0
min 0.8 0.7 1.3 0.6 0.6 0.6 0.5 0.8 0.4 0.2 1.0 0.9
stdev 0.6 0.4 1.2 0.5 2.7 2.0 0.7 0.5 0.6 0.7 0.9 0.4
20-Day Biochemical Oxygen Demand
month NC11 AC ANC SAR GS N403 ROC BC117 NCF117 B210 LVC2 BBT
JAN 3.6 4 2.8 1.9 1.6 1.8 3.3 2.5 2.6 1.9 4.4 3.1FEB9.5 2.4 2.5 2.2 2.3 3.2 2.4 1.2 8.5
MAR 2.9 5.7 5.1 4.1 3.2 3.5 4.5 6.6 3.3 1.5 5.7 2.2
APR 2.5 2.9 5.2 5.3 3.1 4.1 3.7 5.6 3.9 5.7 2.5
MAY 3.9 3.9 4.9 4.0 3.7 4.9 5.6 5.2 3.2 3.3 9.1 3.5
JUN 4.5 4.9 >8.9 3.2 >9.1 >9.0 3.3 4.5 2.8 3.1 3.9 3.5
JUL 5.3 7.3 4.5 2.8 7.8 8.0 6.0 2.3 1.5 3.2 8.3AUG3.0 3.1 4.6 3.2 14.8 5.5 4.6 4.7 2.0 3.3 8.7 3.3
SEP 4.0 4.3 5.5 4.6 4.4 5.4 4.4 3.9 2.3 5.4 5.5 3.9
OCT 3.1 2.4 5.6 4.8 3.4 4.0 4.4 5.5 4.0 4.3 4.8 3.9
NOV
DEC
median 3.6 4.0 5.0 3.6 3.7 4.0 4.4 4.2 2.7 3.3 5.7 3.4mean3.6 4.3 5.3 3.6 5.2 4.3 4.3 4.2 3.0 3.1 6.5 3.2
max 5.3 7.3 9.5 5.2 14.8 8.0 6.0 6.6 5.6 5.4 9.1 3.9
min 2.5 2.4 2.8 1.9 1.6 1.8 2.3 2.3 1.5 1.2 3.9 2.2
stdev 0.9 1.5 1.9 1.1 4.0 1.9 1.1 1.4 1.2 1.3 2.0 0.6
47
Table 2.17 Fecal Coliform (cfu/100 ml) during 2008 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 30 21 27 19 14 8 5 2 2 2 JAN 36 40 64 26 36
FEB 52 52 46 31 31 25 16 8 1 10 FEB 31 40 20 27 82
MAR 460 30 35 40 50 35 12 4 4 9 MAR 11 15 12 22 13
APR 26 33 28 37 15 8 8 4 6 6 APR 8 13 37 68 29
MAY 36 80 114 63 41 23 6 9 3 8 MAY 7 27 64 46 100
JUN 8 37 72 42 22 10 20 16 6 2 JUN 4 17 31 40 163
JUL 11 15 13 32 16 10 2 2 < 1 3 JUL 4 2 17 15 28
AUG 48 84 48 20 13 4 < 2 4 < 2 < 2 AUG 15 19 38 40 58
SEP 23 58 91 57 19 11 3 < 1 1 1 SEP 48 164 94 44 100
OCT 54 164 48 44 37 19 4 4 < 2 11 OCT 31 20 31 26 34
NOV 98 104 40 33 19 8 19 2 29 4 NOV 260 2,000 220 420 580
DEC 45 5 19 8 13 28 4 24 52 13 DEC 500 219 188 54 33
mean 74 57 48 36 24 16 9 7 12 6 mean 80 215 68 69 105
std dev 119 43 29 15 12 9 6 7 16 4 std dev 144 542 65 107 149
max 460 164 114 63 50 35 20 24 52 13 max 500 2,000 220 420 580
min 8 5 13 8 13 4 2 2 1 1 min 4 2 12 15 13
Geomean 40 41 41 32 22 13 7 5 5 5 Geomean 24 38 46 42 59
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 51 90 100 64 840 82 119 430 146 JAN 119 110 119 110 42 240 JAN 46 58 116 44 88
FEB 120 700 570 28 109 17 28 240 75 FEB 64 28 20 108 35 192 FEB 22 33 17 25 46
MAR 104 118 73 64 480 14 240 1,200 490 MAR 430 32 32 100 82 108 MAR 19 47 48 146 37
APR 56 144 46 98 28 36 118 1,455 109 APR 2,300 600 230 80 230 240 APR 64 91 33 84 64
MAY 560 96 73 114 182 134 500 819 1,550 MAY 162 34 164 29 72 65 MAY 118 58 128 85 137
JUN 110 80 100 400 115 110 100 637 46 JUN 230 28 73 819 1,000 84 JUN 4 31 96 32 78
JUL 208 773 540 144 28 682 46 1,364 91 JUL 82 64 76 235 66 52 JUL 146 24 45 37
AUG 100 520 204 1,091 30,000 1,050 591 1,819 9,400 AUG 195 146 120 109 637 176 AUG 182 58 73 135 37
SEP 32 150 185 172 130 5 135 550 2,000 SEP 273 104 86 285 455 2,350 SEP 5,500 2,200 319 230 419
OCT 290 300 145 280 5,100 127 270 910 2,273 OCT 305 100 80 92 546 500 OCT 95 104 48 120 56
NOV 55 1,091 155 210 455 195 210 1,000 145 NOV 120 48 74 182 620 760 NOV 64 773 50 95 51
DEC 91 546 82 82 127 546 181 490 181 DEC 1,600 260 148 216 270 819 DEC 23 140 223 593 196
mean 148 384 189 229 3,133 250 212 910 1,376 mean 490 130 102 197 338 466 mean 524 301 105 136 104
std dev 142 322 170 279 8,213 317 166 455 2,542 std dev 676 156 56 200 299 621 std dev 1,501 606 87 149 105
max 560 1,091 570 1,091 30,000 1,050 591 1,819 9,400 max 2,300 600 230 819 1,000 2,350 max 5,500 2,200 319 593 419
min 32 80 46 28 28 5 28 240 46 min 64 28 20 29 35 52 min 4 24 17 25 37
Geomean 106 258 139 142 311 94 154 788 357 Geomean 254 80 85 141 197 244 Geomean 69 95 76 92 75
48
0
10
20
30
40
50
60
70
80
90
100
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, 1995-2007 versus 2008.
1995-2007
2008
49
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 2008 are used in these comparisons.
3.1 Introduction
The NC Division of Water Quality prepares a basinwide water quality plan for each of the
seventeen major river basins in the state every five years (NCDENR, DWQ Cape Fear
River Basinwide Water Quality Plan, October 2005). The basinwide approach is a
non-regulatory watershed based approach to restoring and protecting the quality of North
Carolina’s surface waters. The first basinwide plan for the Cape Fear River was completed
in 1996 and five-year interval updates have been completed in 2000 and 2005.
The goals of the basinwide program are to: -Identify water quality problems and restore full use to impaired waters.
-Identify and protect high value resource waters.
-Protect unimpaired waters while allowing for reasonable economic growth.
DWQ accomplishes these goals through the following objectives:
-Collaborate with other agencies to develop appropriate management strategies.
-Assure equitable distribution of waste assimilative capacity. -Better evaluate cumulative effects of pollution.
-Improve public awareness and involvement.
The US Geological Survey (USGS) identifies 6 major hydrological areas in the Cape Fear
River Basin. Each of these hydrologic areas is further divided into subbasins by DWQ. There are 24 subbasins within the Cape Fear River basin, each denoted by six digit numbers, 03-06-01 to 03-06-24 (NCDENR-DWQ, October 2005).
All surface waters in the state are assigned a primary classification that is appropriate to
the best uses of that water. North Carolina’s Water Quality Standards Program adopted
50
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 a statewide fish consumption advisory 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:
Standard exceeded in < 10% of samples = Supporting
Standard exceeded in > 10% of samples = Impaired Less than 10 samples collected = Not Rated DO and pH standard
exceeded in swamps = 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 status is based on levels noted to be problematic in the
scientific literature and our own published research. Based on data from four years of
nutrient addition bioassay experiments using water from the Black and Northeast Cape
Fear Rivers, Colly Creek and Great Coharie Creek, the UNCW-AEL considers total
phophorus levels of 500 µg/L or greater potentially harmful to water quality in all the waters
of the Cape Fear River watershed. Nitrate levels of 200 µg/L, 500 µg/L and 1,000 µg/L in
51
small streams, mainstem blackwater stations (NCF117, NCF6, B210) and mainstem Cape
Fear River stations, respectively, are considered harmful to water quality. These nutrient levels may lead to algal blooms, high bacteria levels and high biochemical oxygen demand
(BOD) in blackwater streams (Mallin et al., 2001; 2002; 2004). Water quality status for
nutrient species at the mainstem Cape Fear River stations was evaluated with a higher
standard for nutrients because its waters are quite different than the blackwater areas and
are able to better assimilate higher nutrient levels.
Our system lists a sampling location as having good quality (G) if the standard is
exceeded in none or 1 sample out of 12 measurements (<10%), fair quality (F) if standard is exceeded in 2 or 3 or 12 of measurements (11-25%), or poor quality (P) if 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 2008 LCFRP data.
52
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 present.
53
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 101.5 freshwater miles Supporting 115.1 freshwater miles
Not Rated 40.1 freshwater miles Not Rated 4.8 freshwater miles
Not Rated 1,593.2 freshwater acres No Data 153.1 freshwater miles
No Data 131.4 freshwater miles No Data 2,510.8 freshwater acres
No Data 917.6 freshwater acres
*Brown’s Creek, rated as impaired in the 2000 CFRBWQP, was upgraded in the 2005
plan (NCDENR DWQ CFRWQBP, July 2000 and NCDENR DWQ CFRWQBP, October 2005).
Data collection: NC11 since June 1995, BRN & HAM since February 1996 Sampling relevance: Represents water entering the Lower Cape Fear River watershed
from the middle basin (NC11). There are also concentrated animal operations within the
area (BRN and HAM).
UNCW Aquatic Ecology Laboratory Evaluation
BRN - representative of small tributaries NC11 – Main stem of the Cape Fear River
deep channel, freshwater with minor tidal influence
Dissolved Oxygen ratings for BRN and NC11 were both good. At HAM the rating was fair,
with values exceeding the NC State standard 25% of the time (Table 3.3.1).
All sites within this subbasin had a good rating for chlorophyll a concentrations (Table
54
3.3.1). The North Carolina State standard for chlorophyll a of 40 µg/L was not exceeded at any station during 2008. Of note is that chlorophyll a concentrations at all three stations
was greater than 30 µg/L during August.
For fecal coliform bacteria concentrations NC11 had a fair rating with concentrations
exceeding the NC State Standard in 17% of twelve samples (Table 3.3.1). BRN and HAM
received a poor rating 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 rated as poor (above standard 42% of the time) and HAM rated as fair
(above the standard 25% of the time). 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 2008 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 F G
NC11 G G F G G G
55
56
57
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:
58
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
59
M35 – represents wide estuary
Sites given a good rating for dissolved oxygen include AC, DP, IC, M54, 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 NAV (17%), HB (25%), BRR (25%), and M61 (25%). LVC2 was rated poor with samples below the standard 42% of the time.
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 2008, although there were several that were at or
near 40 µg/L in the middle estuary during the summer.
All but two sites within this subbasin had a good rating for fecal coliform bacteria
concentrations (Table 3.4.1). LVC2 and AC each had two samples (17%) exceed the 200
cfu/100mL North Carolina State human contact standard during 2008.
All the LCFRP sites in this subbasin had a good rating for field turbidity. The station NAV
and those upstream were evaluated using the NC State Standard for freshwater of 50 NTU
while all stations downstream of NAV were evaluated with the NC State Standard for
brackish waters of 25 NTU.
AC and IC were both rated fair for nitrate, exceeding the recommended UNCW-AEL
standard 17% of the time (Table 3.4.1) LVC2 was rated poor for nitrate, exceeding the
UNCW-AEL recommended standard (200 mg/L) 75% of the time. All stations rated good
for total phosphorus.
60
Table 3.4.1 UNCW AEL 2008 evaluation for subbasin 03-06-17
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
LVC2 P G F G P G
AC G G F G F G
DP G G G G G G
IC G G G G F G
NAV F G G G G G
HB F G G G G G
BRR F G G G G G
M61 F G G G G G
M54 G G G G G G
M42 G G G G G G
M35 G G G G G G
M23 G G G G G G
M18 G G G G G G
SPD G G G G G G
61
Figure 3.4.1 Dissolved oxygen concentrations at LVC2, rated poor for 2008. The dashed line shows the NC State Standard for swampwater, 4.0 mg/L.
0
1
2
3
4
5
6
7
8
9
10
11
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
)
62
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.
63
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 was found to have a poor rating for dissolved oxygen concentrations in 2008 (Table
3.5.1). The North Carolina State Standard for swampwater of 4.0 mg/L was not met 33%
of the time. The lowest levels were found in summer and late fall (Figure 3.5.1).
SR had a good rating for chlorophyll a exceeding the NC State standard of 40 µg/L on
one occasion (Table 3.5.1, Figure 3.5.1).
SR had a poor water quality status for fecal coliform bacteria concentrations, exceeding
the NC State Standard of 200 CFU/100mL in 33% of samples (Table 3.5.1). The highest concentration was in June (819 CFU/100mL).
SR had a good rating for field turbidity, nitrate and total phosphorus (Table 3.5.1).
64
Table 3.5.1 UNCW AEL 2008 evaluation for subbasin 03-06-18
Station Dissolved Oxygen Chlorophyll a Fecal Coliform Field Turbidity Nitrate Total Phosphorus
SR P G P G G G
Figure 3.5.1 Dissolved oxygen (mg/L) at SR during 2008. The dashed line shows the NC
State Standard for swampwater DO of 4.0 mg/L.
Figure 3.5.2 Fecal Coliform Bacteria (cfu/100 mL) at SR during 2008. The dashed line
shows the NC State Standard of 200 cfu/100 mL.
0
1
2
3
4
5
6
7
8
9
10
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Dis
s
o
l
v
e
d
O
x
y
g
e
n
(
m
g
/
L
)
0
100
200
300
400
500
600
700
800
900
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
/
10
0
mL
)
65
66
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
67
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 and LCO had a good rating for dissolved oxygen concentrations during 2008 (Table
3.6.1). GCO was rated fair with two samples (17%) below the NC State Standard of 4.0
mg/L.
All sites within this subbasin had a good rating for chlorophyll a and field turbidity concentrations (Table 3.6.1).
6RC had a poor rating for fecal coliform bacteria with 50% of samples exceeding the NC
State human contact standard of 200 CFU/100mL (Table 3.6.1). LCO had a fair rating with
a 17% rate and GCO had a good rating for fecal coliform bacteria.
Nitrate levels were rated poor at 6RC, LCO and GCO, exceeding 200 µg/L in 83%, 67%,
and 33% of the samples, respectively (Table 3.6.1, Figure 3.6.1).
68
Total phosphorus was rated good at 6RC and LCO and rated fair at GCO with levels above
500 µg/L 25% of the time (Table 3.6.1).
Table 3.6.1 UNCW AEL 2008 evaluation for subbasin 03-06-19
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
6RC G G P G P G
LCO G G F G P G
GCO F G G G P F
Figure 3.6.1 Nitrate concentrations (µg/L) at 6RC, LCO, and GCO during 2008. The
dashed line shows the UNCW-AEL standard of 200 µg/L.
0
200
400
600
800
1,000
1,200
1,400
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
6RC
LCO
GCO
69
70
71
72
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
73
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
74
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 generally low with B210 and COL rating as fair with samples exceeding the NC State standard 17% and 18% of the time respectively
(Table 3.7.1). BBT samples were not analyzed for fecal coliform bacteria.
All stations rated good for both nutrient species. BBT samples were not analyzed for
nutrients.
Table 3.7.1 UNCW AEL 2008 evaluation for subbasin 03-06-20
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
B210 G G F G G G
COL G G F G G G
BBT G G G
75
76
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.
77
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 21.7 freshwater miles Supporting 57.3 freshwater miles Not Rated 38.9 freshwater miles No Data 88.1 freshwater miles
No Data 84.7 freshwater miles
Data collection: June 1997 – present Sampling relevance: Below Mount Olive Pickle Plant
UNCW Aquatic Ecology Laboratory Evaluation
NC403 - slow moving headwaters of NE Cape Fear River
NC403 had a poor rating for dissolved oxygen concentrations, not meeting the NC State
Standard for swampwater of 4.0 mg/L in 33% of the samples (Table 3.8.1, Figure 3.8.1)
NC403 had a fair rating for chlorophyll a and 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.
Field turbidity was rated as good at NC 403 (Table 3.8.1).
NC403 had a poor rating for fecal coliform bacteria with samples exceeding the NC
State standard for human contact (200 cfu/100 mL) 33% of the time.
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
78
about the elevated nitrate levels that are periodically found at this site since these levels increase the likelihood of algal blooms and excessive aquatic macrophyte growth. Total
phosphorus had a good rating at this location for 2008.
Table 3.8.1 UNCW AEL 2008 evaluation for subbasin 03-06-21
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
NC403 P F P G P G
Figure 3.8.1 Dissolved oxygen (mg/L) and nitrate (µg/L) concentrations at NC403 during
2008. 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
1
2
3
4
5
6
7
8
9
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
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
79
Figure 3.9.1 Fecal Coliform Bacteria concentrations (cfu/100 mL) at NC403 during 2008. The dashed line shows the NC State standard of 200 cfu/100 mL.
0
200
400
600
800
1000
1200
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
/
10
0
ml
)
80
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
81
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 25% of the time.
For chlorophyll a concentrations SAR, LRC and ROC had a good rating (Table 3.9.1). GS
was rated fair with samples exceeding the NC State Standard 17% of the time. PB was
rated poor, exceeding the standard 33% of the time.
Fecal coliform bacteria concentrations were rated using the NC State standard of 200
CFU/100 mL for human contact. GS and LRC each had a fair rating with both exceeding
the standard 25% of the time (Table 3.9.1). SAR, PB and ROC each had a poor rating
with 50%, 42% and 42% of samples above the standard, respectively. Fecal coliform
bacteria concentrations are shown graphically in Figure
3.9.1.
82
All sites had a good rating for field turbidity concentrations (Table 3.9.1). Mean levels were less than 15 NTU for all sites within this subbasin for 2008.
For nitrate GS and LRC had a good rating (Table 3.9.1). SAR, PB, and ROC all had a poor
rating with levels exceeding the UNCW AEL standard (200 µg/L) 50%, 58%, 33% and 92%
of the time, respectively. Nitrate levels for SAR, PB and ROC are shown graphically in
Figure 3.9.2.
For total phosphorus all stations were rated good (Table 3.9.1).
Table 3.9.1 UNCW AEL 2008 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 F F F G G G
PB G P P G P G
LRC G G F G G G
ROC G G P G P G
Figure 3.9.1 Fecal coliform bacteria at SAR, PB and ROC (cfu/100mL) during 2008. The dashed line is the NC State Standard for human contact of 200 cfu/100mL).
0
200
400
600
800
1000
1200
1400
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
ROC
83
Figure 3.9.2 Nitrate-N concentrations (µg/L) at SAR, PB and ROC during 2008. The
dashed line represents the UNCW AEL standard of 200 µg/L.
0
200
400
600
800
1,000
1,200
1,400
1,600
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Ni
t
r
a
t
e
(
µg/
L
)
SAR
PB
ROC
84
85
86
3.10 Cape Fear River Subbasin 03-06-23
Location: Area near Burgaw and Angola swamp
Counties: Pender
Waterbodies: Northeast Cape Fear River,Burgaw Creek
Municipalities: Burgaw NPDES Dischargers: 7 @ 3.8 million gallons per day Concentrated Swine Operations: 52
LCFRP monitoring stations (DWQ #):
ANC (69), BCRR (82), BC117 (83), NCF117 (84), NCF6 (85)
DWQ monitoring stations: NCF117
This subbasin is located in the outer coastal plain where many streams are slow flowing
blackwater streams that often dry up during the summer months. Most of the watershed is
87
forested with some agriculture and increasing human development.
The CFR Basinwide Water Quality Plan lists the following ratings for this subbasin:
Aquatic Life Recreation
Supporting 73.8 freshwater miles Supporting 39.5 freshwater miles
Not Rated 45.1 freshwater miles Supporting 1.0 saltwater acre
Impaired 23.4 freshwater miles Not Rated 11.6 freshwater miles
No Data 233.2 freshwater miles Not Data 324.5 freshwater miles
Not Rated 1.0 saltwater acre
UNCW Aquatic Ecology Laboratory Evaluation
NCF117 - Northeast Cape Fear River at US117
Data collection: NCF117 & NCF6 since June 1995, others from February 1996
Sampling relevance: point and non-point source dischargers
ANC - Angola Creek BC117 - Burgaw Canal at US 117
88
For dissolved oxygen BC117, NCF117 and NCF6 had a good rating when using the 4.0
mg/L standard (Table 3.10.1). ANC had a fair rating with sub-standard samples 25% of the time. SC-CH and BCRR had a poor rating with substandard samples 33% and 58% of the
time. DO levels for ANC, BCRR and SC-CH are seen in Figure 3.10.1.
For chlorophyll a BC117, NCF117 and NCF6 rated good (Table 3.10.1). ANC and BCRR
rated fair exceeding the NC State Standard of 40 µg/L 17% of the time at both sites.
Chlorophyll a was not analyzed at SC-CH.
For fecal coliform bacteria NCF117, NCF6 and SC-CH had a good rating (Table 3.10.1). ANC had a fair rating, exceeding the standard 25% of the time. BC117 and BCRR each
had a poor rating exceeding the human contact standard 100% and 42% of the time,
respectively. Fecal coliform bacteria concentrations for BC117 and BCRR are shown in
Figure 3.10.2.
All stations were rated good for field turbidity except SC-CH which had field turbidity values exceeding the NC State Standard for tidal waters of 25 NTU 33% 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). ANC and BC117 were both rated poor for nitrate as well,
exceeding the UNCW AEL standard 33% and 42% of the time, respectively.
Table 3.10.1 UNCW AEL 2008 evaluation for subbasin 03-06-23
Station Dissolved
Oxygen
Chlorophyll
a
Fecal
Coliform
Field
Turbidity
Nitrate Total
Phosphorus
ANC F F F G P G
BC117 G G P G P P
BCRR P F P G P G
NCF117 G G G G G G
NCF6 G G G G G G
SC-CH P G P
89
Figure 3.10.1 Dissolved oxygen concentrations (mg/L) at BCRR, SC-CH and ANC for 2008. The dashed line shows the NC State Standard for swampwater, 4.0 mg/L.
Figure 3.10.2 Fecal coliform bacteria concentrations (cfu/100mL) at BC117, BCRR and ANC during 2008. The dashed line shows the NC State Standard for human contact, 200
cfu/100 mL.
0
2
4
6
8
10
12
14
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
)
BCRR
SC-CH
ANC
0
200
400
600
800
1000
1200
1400
1600
1800
2000
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
ANC
90
91
92
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.
93