Lower Cape Fear River Program 2012 reportEnvironmental Assessment of the Lower
Cape Fear River System, 2012
By
Michael A. Mallin, Matthew R. McIver and James F. Merritt
October 2013
CMS Report No. 13-02
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’s (UNCW) Aquatic Ecology Laboratory perform the sampling effort. The
LCFRP currently encompasses 36 water sampling stations throughout the lower Cape
Fear, Black, and Northeast Cape Fear River watersheds. The LCFRP sampling
program includes physical, chemical, and biological water quality measurements and
analyses of the benthic and epibenthic macroinvertebrate communities, and has in the
past included assessment of the fish communities. Principal conclusions of the UNCW
researchers conducting these analyses are presented below, with emphasis on water
quality of the period January - December 2012. The opinions expressed are those of
UNCW scientists and do not necessarily reflect viewpoints of individual contributors to
the Lower Cape Fear River Program.
The mainstem lower Cape Fear River is a 6th order stream characterized by periodically
turbid water containing moderate to high levels of inorganic nutrients. It is fed by two
large 5th order blackwater rivers (the Black and Northeast Cape Fear Rivers) that have
low levels of turbidity, but highly colored water with less inorganic nutrient content than
the mainstem. While nutrients are reasonably high in the river channels, major algal
blooms have until recently been rare because light is attenuated by water color or
turbidity, and flushing is usually high (Ensign et al. 2004). During periods of low flow (as
in 2008-2011) 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 2012
were slightly lower than the average for 1995-2011. Dissolved oxygen levels were
lowest during the summer and early fall, often falling below the state standard of 5.0
mg/L at several river and upper estuary stations. There is a dissolved oxygen sag in the
main river channel that begins at Station DP below a paper mill discharge and near the
Black River input, and persists into the mesohaline portion of the estuary. Mean oxygen
levels were highest at the upper river stations NC11 and AC and in the middle to lower
estuary at stations M35 to M18. Lowest mainstem average 2012 DO levels occurred at
the lower river and upper estuary stations DP, IC, NAV, HB, BRR and M61 (6.3-6.9
mg/L). As the water reaches the lower estuary higher algal productivity, mixing and
ocean dilution help alleviate oxygen problems.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River. These rivers are classified as blackwater systems because
of their tea colored water. The Northeast Cape Fear River often seems to be more
oxygen stressed than the Black River; as such, in 2012 Stations NCF117 and B210,
representing those rivers, had average DO concentrations of 5.8 and 6.5 mg/L,
respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2012. Stations BCRR and SR had DO levels below 4.0 mg/L
67% of the occasions sampled, with NC403 58%, BC117 50%, LVC2 42%, GS 33%
and NCF117 and SC-CH 25%. Considering all sites sampled in 2012, we rated 29% as
poor for dissolved oxygen, 18% as fair, and 53% as good, a decrease from 2011
Annual mean turbidity levels for 2012 were lower than the long-term average in all
estuary stations. Highest mean turbidities were at NAV and HB (17-20 NTU) with
turbidities generally low in the middle to lower estuary. Stations NAV, HB and BRR
exceeded the estuarine turbidity standard on four, three and two occasions,
respectively. Turbidity was considerably lower in the blackwater tributaries (Northeast
Cape Fear River and Black River) than in the mainstem river. Average turbidity levels
were low in the freshwater streams, with the exception of PB, SR and to a lesser extent
LCO.
Regarding stream stations, chronic or periodic high nitrate levels were found at a
number of sites, including BC117 (Burgaw Creek below Burgaw), ROC (Rockfish
Creek), 6RC (Six Runs Creek), SAR (Sarecta), and GCO (Great Coharie Creek) and
BRN (Browns Creek). Average chlorophyll a concentrations across all sites were
similar to long-term average. We note the highest levels in the river and estuary
occurred in mid-summer; during the growing season May-September river flow as
measured by USGS at Lock and Dam #1 was lower for 2012 compared with the 1995-
2011 long-term average (1,719 CFS compared with 3,361 CFS). Low discharge allows
for settling of suspended solids and more light penetration into the water column, where
the relatively high nutrient levels and slow moving waters support algal bloom formation.
The most troublesome occurrence was the recurrence of cyanobacteria (i.e. blue-green
algal blooms) in the Cape Fear River during August in the river near NC11 (see report
cover). These consisted largely of Microcystis aeruginosa, which produce toxins, and
their occurrence in bloom formation has occurred every summer since 2009. We note
that fish kills were not reported related to the blooms. Stream algal blooms exceeding
20 µg/L in 2012 occurred at ANC, NC403, PB and LRC. Several stream stations,
particularly BC117, BCRR, PB, BRN, HAM (Hammond Creek), GS, N403, LRC and SC-
CH showed high fecal coliform bacteria counts on a number of occasions.
For the 2012 period UNCW rated 100% of the stations as good in terms of chlorophyll a.
For turbidity 91% of the sites were rated good, 6% fair and 3% poor. Fecal coliform
bacteria counts were high in the system in 2012 and the lower estuary had high
enterococcus on some occasions. For bacterial water quality overall, 45% of the sites
rated as poor, 21% as fiar, and 33% as good in 2012. 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. In addition, by our UNCW standards excessive nitrate and
phosphorus concentrations were problematic at a number of stations (Chapter 3).
Table of Contents
1.0 Introduction...........................................................................………...............…........1
1.1 Site Description................................................………....................................2
1.2 Report Organization……………………………………………………… ……..3
2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River
and Estuary………………………………………………..…………………….....….. ….8
Physical Parameters..…......................………..........................................……....11
Chemical Parameters…....……..……….........................................................…..14
Biological Parameters.......……….....……......................................................…..17
Executive Summary
Multiparameter water sampling for the Lower Cape Fear River Program (LCFRP) has
been ongoing since June 1995. Scientists from the University of North Carolina
Wilmington’s (UNCW) Aquatic Ecology Laboratory perform the sampling effort. The
LCFRP currently encompasses 36 water sampling stations throughout the lower Cape
Fear, Black, and Northeast Cape Fear River watersheds. The LCFRP sampling
program includes physical, chemical, and biological water quality measurements and
analyses of the benthic and epibenthic macroinvertebrate communities, and has in the
past included assessment of the fish communities. Principal conclusions of the UNCW
researchers conducting these analyses are presented below, with emphasis on water
quality of the period January - December 2012. The opinions expressed are those of
UNCW scientists and do not necessarily reflect viewpoints of individual contributors to
the Lower Cape Fear River Program.
The mainstem lower Cape Fear River is a 6th order stream characterized by periodically
turbid water containing moderate to high levels of inorganic nutrients. It is fed by two
large 5th order blackwater rivers (the Black and Northeast Cape Fear Rivers) that have
low levels of turbidity, but highly colored water with less inorganic nutrient content than
the mainstem. While nutrients are reasonably high in the river channels, major algal
blooms have until recently been rare because light is attenuated by water color or
turbidity, and flushing is usually high (Ensign et al. 2004). During periods of low flow (as
in 2008-2011) 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 2012
were slightly lower than the average for 1995-2011. Dissolved oxygen levels were
lowest during the summer and early fall, often falling below the state standard of 5.0
mg/L at several river and upper estuary stations. There is a dissolved oxygen sag in the
main river channel that begins at Station DP below a paper mill discharge and near the
Black River input, and persists into the mesohaline portion of the estuary. Mean oxygen
levels were highest at the upper river stations NC11 and AC and in the middle to lower
estuary at stations M35 to M18. Lowest mainstem average 2012 DO levels occurred at
the lower river and upper estuary stations DP, IC, NAV, HB, BRR and M61 (6.3-6.9
mg/L). As the water reaches the lower estuary higher algal productivity, mixing and
ocean dilution help alleviate oxygen problems.
The Northeast Cape Fear and Black Rivers generally have lower DO levels than the
mainstem Cape Fear River. These rivers are classified as blackwater systems because
of their tea colored water. The Northeast Cape Fear River often seems to be more
oxygen stressed than the Black River; as such, in 2012 Stations NCF117 and B210,
representing those rivers, had average DO concentrations of 5.8 and 6.5 mg/L,
respectively. Several stream stations were severely stressed in terms of low dissolved
oxygen during the year 2012. Stations BCRR and SR had DO levels below 4.0 mg/L
67% of the occasions sampled, with NC403 58%, BC117 50%, LVC2 42%, GS 33%
and NCF117 and SC-CH 25%. Considering all sites sampled in 2012, we rated 29% as
poor for dissolved oxygen, 18% as fair, and 53% as good, a decrease from 2011
Annual mean turbidity levels for 2012 were lower than the long-term average in all
estuary stations. Highest mean turbidities were at NAV and HB (17-20 NTU) with
turbidities generally low in the middle to lower estuary. Stations NAV, HB and BRR
exceeded the estuarine turbidity standard on four, three and two occasions,
respectively. Turbidity was considerably lower in the blackwater tributaries (Northeast
Cape Fear River and Black River) than in the mainstem river. Average turbidity levels
were low in the freshwater streams, with the exception of PB, SR and to a lesser extent
LCO.
Regarding stream stations, chronic or periodic high nitrate levels were found at a
number of sites, including BC117 (Burgaw Creek below Burgaw), ROC (Rockfish
Creek), 6RC (Six Runs Creek), SAR (Sarecta), and GCO (Great Coharie Creek) and
BRN (Browns Creek). Average chlorophyll a concentrations across all sites were
similar to long-term average. We note the highest levels in the river and estuary
occurred in mid-summer; during the growing season May-September river flow as
measured by USGS at Lock and Dam #1 was lower for 2012 compared with the 1995-
2011 long-term average (1,719 CFS compared with 3,361 CFS). Low discharge allows
for settling of suspended solids and more light penetration into the water column, where
the relatively high nutrient levels and slow moving waters support algal bloom formation.
The most troublesome occurrence was the recurrence of cyanobacteria (i.e. blue-green
algal blooms) in the Cape Fear River during August in the river near NC11 (see report
cover). These consisted largely of Microcystis aeruginosa, which produce toxins, and
their occurrence in bloom formation has occurred every summer since 2009. We note
that fish kills were not reported related to the blooms. Stream algal blooms exceeding
20 µg/L in 2012 occurred at ANC, NC403, PB and LRC. Several stream stations,
particularly BC117, BCRR, PB, BRN, HAM (Hammond Creek), GS, N403, LRC and SC-
CH showed high fecal coliform bacteria counts on a number of occasions.
For the 2012 period UNCW rated 100% of the stations as good in terms of chlorophyll a.
For turbidity 91% of the sites were rated good, 6% fair and 3% poor. Fecal coliform
bacteria counts were high in the system in 2012 and the lower estuary had high
enterococcus on some occasions. For bacterial water quality overall, 45% of the sites
rated as poor, 21% as fiar, and 33% as good in 2012. 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. In addition, by our UNCW standards excessive nitrate and
phosphorus concentrations were problematic at a number of stations (Chapter 3).
Table of Contents
1.0 Introduction...........................................................................………...............…........1
1.1 Site Description................................................………....................................2
1.2 Report Organization……………………………………………………… ……..3
2.0 Physical, Chemical, and Biological Characteristics of the Lower Cape Fear River
and Estuary………………………………………………..…………………….....….. ….8
Physical Parameters..…......................………..........................................……....11
Chemical Parameters…....……..……….........................................................…..14
Biological Parameters.......……….....……......................................................…..17
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 2012.
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
17-year (1995-2012) data base that is available to the public, and is used as a teaching
tool for programs like UNCW’s River Run. Using this monitoring data as a framework
the program goals also include focused scientific projects and investigation of pollution
episodes. The scientific aspects of the program are carried out by investigators from
the University of North Carolina Wilmington Center for Marine Science. The monitoring
program was developed by the Lower Cape Fear River Program Technical Committee,
which consists of representatives from UNCW, the North Carolina Division of Water
Quality, The NC Division of Marine Fisheries, the US Army Corps of Engineers,
technical representatives from streamside industries, the Cape Fear Public Utility
Authority, Cape Fear Community College, Cape Fear River Watch, the North Carolina
Cooperative Extension Service, the US Geological Survey, forestry and agriculture
organizations, and others. This integrated and cooperative program was the first of its
kind in North Carolina.
Broad-scale monthly water quality sampling at 16 stations in the estuary and lower river
system began in June 1995 (UNCW Aquatic Ecology Laboratory, directed by Dr.
Michael Mallin). Sampling was increased to 34 stations in February of 1996, 35 stations
in February 1998, and 36 stations in 2005. The Lower Cape Fear River Program added
another component concerned with studying the benthic macrofauna of the system in
1996. This component is directed by Dr. Martin Posey and Mr. Troy Alphin of the
UNCW Biology Department and includes the benefit of additional data collected by the
Benthic Ecology Laboratory under Sea Grant and NSF sponsored projects in the Cape
Fear Estuary. These data are collected and analyzed depending upon the availability of
funding. The third major biotic component (added in January 1996) was an extensive
1
fisheries program directed by Dr. Mary Moser of the UNCW Center for Marine Science
Research, with subsequent (1999) overseeing by Mr. Michael Williams and Dr. Thomas
Lankford of UNCW-CMS. This program involved cooperative sampling with the North
Carolina Division of Marine Fisheries and the North Carolina Wildlife Resources
Commission. The fisheries program ended in December 1999, but was renewed with
additional funds from the Z. Smith Reynolds Foundation from spring – winter 2000. The
regular sampling that was conducted by UNCW biologists was assumed by the North
Carolina Division of Marine Fisheries.
1.1. Site Description
The mainstem of the Cape Fear River is formed by the merging of the Haw and the
Deep Rivers in Chatham County in the North Carolina Piedmont. However, its drainage
basin reaches as far upstream as the Greensboro area (Fig. 1.1). The mainstem of the
river has been altered by the construction of several dams and water control structures.
In the coastal plain, the river is joined by two major tributaries, the Black and the
Northeast Cape Fear Rivers (Fig. 1.1). These 5th order blackwater streams drain
extensive riverine swamp forests and add organic color to the mainstem. The
watershed (about 9,164 square miles) is the most heavily industrialized in North
Carolina with 203 permitted wastewater discharges with a permitted flow of
approximately 429 million gallons per day, and (as of 2010) over 2.07 million people
residing in the basin (NCDENR Basinwide Information Management System (BIMS) &
2010 Census). Approximately 23% of the land use in the watershed is devoted to
agriculture and livestock production (2006 National Land Cover Dataset), with livestock
production dominated by swine and poultry operations. Thus, the watershed receives
considerable point and non-point source loading of pollutants. However, the estuary is
a well-flushed system, with flushing time ranging from 1 to 22 days with a median
flushing time of about seven days, much shorter than the other large N.C. estuaries to
the north (Ensign et al. 2004).
Water quality is monitored by boat at nine stations in the Cape Fear Estuary (from
Navassa to Southport) and one station in the Northeast Cape Fear Estuary (Table 1.1;
Fig. 1.1). We note that after July 2011 sampling was discontinued at stations M42 and
SPD, per agreement with the North Carolina Division of Water Quality; and in 2012
sampling was expanded at Smith Creek at the Castle Hayne Road bridge (Table 1.1)
and initiated at a new site along the South River (SR-WC). Riverine stations sampled
by boat include NC11, AC, DP, IC, and BBT (Table 1.1; Fig. 1.1). NC11 is located
upstream of any major point source discharges in the lower river and estuary system,
and is considered to be representative of water quality entering the lower system (we
note that the City of Wilmington and portions of Brunswick County get their drinking
water from the river just upstream of Lock and Dan #1). Station BBT is located on the
Black River between Thoroughfare (a stream connecting the Cape Fear and Black
Rivers) and the mainstem Cape Fear, and is influenced by both rivers. We consider
B210 and NCF117 to represent water quality entering the lower Black and Northeast
Cape Fear Rivers, respectively. Data has also been collected at stream and river
2
stations throughout the Cape Fear, Northeast Cape Fear, and Black River watersheds
(Table 1.1; Fig. 1.1; Mallin et al. 2001).
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
The LCFRP has a website that contains maps and an extensive amount of past water
quality, benthos, and fisheries data gathered by the Program available at:
www.uncw.edu/cms/aelab/LCFRP/.
References Cited
Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511. Mallin, M.A., S.H. Ensign, M.R. McIver, G.C. Shank and P.K. Fowler. 2001. Demographic, landscape, and meteorological factors controlling the microbial pollution of coastal waters. Hydrobiologia 460:185-193. NCDENR. 2005. Cape Fear River Basinwide Water Quality Plan. North Carolina Department of Environment and Natural Resources, Division of Water Quality/Planning, Raleigh, NC, 27699-1617.
3
Table 1.1. Description of sampling locations in the Cape Fear Watershed, 2012,
including UNCW designation and NCDWQ station designation number.
________________________________________________________________
UNCW St. DWQ No. Location
________________________________________________________________
High order river and estuary stations
NC11 B8360000 At NC 11 bridge on Cape Fear River (CFR)
GPS N 34.39663 W 78.26785
AC B8450000 5 km downstream from International Paper on CFR
GPS N 34.35547 W 78.17942
DP B8460000 At DAK America’s Intake above Black River
GPS N 34.33595 W 78.05337
IC B9030000 Cluster of dischargers upstream of Indian Cr. on CFR
GPS N 34.30207 W 78.01372
B210 B9000000 Black River at Highway 210 bridge
GPS N 34.43138 W 78.14462
BBT none Black River between Thoroughfare and Cape Fear River
GPS N 34.35092 W 78.04857
NCF117 B9580000 Northeast Cape Fear River at Highway 117, Castle Hayne
GPS N 34.36342 W 77.89678
NCF6 B9670000 Northeast Cape Fear River near GE dock
GPS N 34.31710 W 77.95383
NAV B9050000 Railroad bridge over Cape Fear River at Navassa
GPS N 34.25943 W 77.98767
HB B9050100 Cape Fear River at Horseshoe Bend
GPS N 34.24372 W 77.96980
BRR B9790000 Brunswick River at John Long Park in Belville
GPS N 34.22138 W 77.97868
M61 B9750000 Channel Marker 61, downtown at N.C. State Port
GPS N 34.19377 W 77.95725
4
M54 B7950000 Channel Marker 54, 5 km downstream of Wilmington
GPS N 34.13933 W 77.94595
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
________________________________________________________________
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
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
5
PB B9130000 Panther Branch below Bay Valley Foods
GPS N 35.13445 W 78.13630
GS B9191000 Goshen Swamp at NC 11
GPS N 35.02923 W 77.85143
SAR B9191500 Northeast Cape Fear River near Sarecta
GPS N 34.97970 W 77.86251
LRC B9460000 Little Rockfish Creek at NC 11
GPS N 34.72247 W 77.98145
ROC B9430000 Rockfish Creek at US 117
GPS N 34.71689 W 77.97961
BCRR B9500000 Burgaw Canal at Wright St., above WWTP
GPS N 34.56334 W 77.93481
BC117 B9520000 Burgaw Canal at US 117, below WWTP
GPS N 34.56391 W 77.92210
SC-CH B9720000 Smith Creek at Castle Hayne Rd.
GPS N 34.25897 W 77.93872
6
Figure 1.1. Map of the Lower Cape Fear River system and the LCFRP sampling stations.
7
2.0 Physical, Chemical, and Biological Characteristics of the
Lower Cape Fear River and Estuary
Michael A. Mallin and Matthew R. McIver
Aquatic Ecology Laboratory
Center for Marine Science
University of North Carolina Wilmington
2.1 - Introduction
This section of the report includes a discussion of the physical, chemical, and biological
water quality parameters, concentrating on the January-December 2012 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 or enterococcus 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. Analysis methods are listed in Table 2.0.
Physical Parameters
Water Temperature, pH, Dissolved Oxygen, Turbidity, Salinity, Conductivity
Field parameters were measured at each site using a YSI 6920 (or 6820) multi-parameter
water quality sonde displayed on a YSI 650 MDS. Each parameter is measured with
individual probes on the sonde. At stations sampled by boat (see Table 1.1) physical
parameters were measured at 0.1 m, the middle of the water column, and at the bottom
(up to 12 m). Occasionally, high flow prohibited the sonde from reaching the actual bottom
and measurements were taken as deep as possible. At the terrestrially sampled stations
(i.e. from bridges or docks) the physical parameters were measured at a depth of 0.1 m.
8
The Aquatic Ecology Laboratory at the UNCW CMS is State-certified by the N.C. Division
of Water Quality to perform field parameter measurements.
Chemical Parameters
Nutrients
A local State-certified analytical laboratory was contracted to conduct all chemical
analyses except for orthophosphate, which is performed at CMS. The following methods
detail the techniques used by CMS personnel for orthophosphate analysis.
Orthophosphate (PO4-3)
Water samples were collected ca. 0.1 m below the surface in triplicate in amber 125 mL
Nalgene plastic bottles and placed on ice. In the laboratory 50 mL of each triplicate was
filtered through separate1.0 micron pre-combusted glass fiber filters, which were frozen
and later analyzed for chlorophyll a. The triplicate filtrates were pooled in a glass flask,
mixed thoroughly, and approximately 100 mL was poured into a 125 mL plastic bottle to be
analyzed for orthophosphate. Samples were frozen until analysis.
Orthophosphate analyses were performed in duplicate using an approved US EPA method
for the Bran-Lubbe AutoAnalyzer (Method 365.5). In this technique the orthophosphate in
each sample reacts with ammonium molybdate and anitmony potassium tartrate in an
acidic medium (sulfuric acid) to form an anitmony-phospho-molybdate complex. The
complex is then reacted with ascorbic acid and forms a deep blue color. The intensity of
the color is measured at a wavelength of 880 nm by a colorimeter and displayed on a chart
recorder. Standards and spiked samples were analyzed for quality assurance.
Biological Parameters
Fecal Coliform Bacteria
Fecal coliform bacteria were analyzed by a State-certified laboratory contracted by the
LCFRP. Samples were collected approximately 0.1 m below the surface in sterile plastic
bottles provided by the contract laboratory and placed on ice for no more than six hours
before analysis. After August 2011 the fecal coliform analysis was changed to
Enterococcus in the estuarine stations downstream of NAV and HB (Stations BRR, M61,
M35, M23 and M18).
Chlorophyll a
The analytical method used to measure chlorophyll a is described in Welschmeyer (1994)
and US EPA (1997) and was performed by CMS personnel. Chlorophyll a concentrations
were determined utilizing the 1.0 micron filters used for filtering samples for
orthophosphate analysis. All filters were wrapped individually in foil, placed in airtight
containers and stored in the freezer. During analysis each filter was immersed in 10 mL of
9
90% acetone for 24 hours, which extracts the chlorophyll a into solution. Chlorophyll a
concentration of each solution was measured on a Turner 10-AU fluorometer. The
fluorometer uses an optimal combination of excitation and emission bandwidth filters which
reduces the errors inherent in the acidification technique. The Aquatic Ecology Laboratory
at the CMS is State-certified by the N.C. Division of Water Quality for the analysis of
chlorophyll a.
Biochemical Oxygen Demand (BOD)
Five sites were originally chosen for BOD analysis. One site was located at NC11,
upstream of International Paper, and a second site was at AC, about 3 miles downstream
of International Paper (Fig.1.1). Two sites were located in blackwater rivers (NCF117 and
B210) and one site (BBT) was situated in an area influenced by both the mainstem Cape
Fear River and the Black River. For the sampling period May 2000-April 2004 additional
BOD data were collected at stream stations 6RC, LCO, GCO, BRN, HAM and COL in the
Cape Fear and Black River watersheds. In May 2004 those stations were dropped and
sampling commenced at ANC, SAR, GS, N403, ROC and BC117 in the Northeast Cape
Fear River watershed for several years. The procedure used for BOD analysis is Method
5210 in Standard Methods (APHA 1995). Samples were analyzed for both 5-day and 20-
day BOD. During the analytical period, samples were kept in airtight bottles and placed in
an incubator at 20o C. All experiments were initiated within 6 hours of sample collection.
Samples were analyzed in duplicate. Dissolved oxygen measurements were made using
a YSI Model 5000 meter that was air-calibrated. No adjustments were made for pH since
most samples exhibited pH values within or very close to the desired 6.5-7.5 range (pH is
monitored during the analysis as well); a few sites have naturally low pH and there was no
adjustment for these samples because it would alter the natural water chemistry and affect
true BOD. Data are presented within for the five original sites.
2.3 - Results and Discussion
This section includes results from monitoring of the physical, biological, and chemical
parameters at all stations for the time period January-December 2012. Discussion of the
data focuses both on the river channel stations and stream stations, which sometimes
reflect poorer water quality than mainstem stations. The contributions of the two large
blackwater tributaries, the Northeast Cape Fear River and the Black River, are represented
by conditions at NCF117 and B210, respectively. The Cape Fear Region did not
experience any significant hurricane activity during this monitoring period (after major
hurricanes in 1996, 1998, and 1999). Therefore this report reflects low to medium flow
conditions for the Cape Fear River and Estuary.
10
Physical Parameters
Water temperature
Water temperatures at all stations ranged from 3.3 to 32.1oC, and individual station annual
averages ranged from 15.9 to 20.9oC (Table 2.1). Highest temperatures occurred during
July and August and lowest temperatures during January. Stream stations were generally
cooler than river stations, most likely because of shading and lower nighttime air
temperatures affecting the shallower waters.
Salinity
Salinity at the estuarine stations (NAV through M18; also NCF6 in the Northeast Cape
Fear River) ranged from 0.1 to 35.1 practical salinity units (psu) and station annual means
ranged from 3.1 to 31.0 psu (Table 2.2). Lowest salinities occurred in spring and also in
September and highest salinities occurred in winter. The annual mean salinity for 2012
was higher than that of the fifteen-year average for 1995-2011 for all of the estuarine
stations (Figure 2.1), due to reduced river flows. Two stream stations, NC403 and PB, had
occasional oligohaline conditions due to discharges from pickle production facilities. SC-
CH is a tidal creek that enters the Northeast Cape Fear River upstream of Wilmington and
salinity there ranged widely, from 0.4 to 10.2 psu.
Conductivity
Conductivity at the estuarine stations ranged from 0.14 to 53.3 mS/cm and from 0.07 to
5.50 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. 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 3.3 to 8.1 and station annual means ranged from 3.7 to 8.0 (Table
2.4). pH was typically lowest upstream due to acidic swamp water inputs and highest
downstream as alkaline seawater mixes with the river water. Low pH values at COL
predominate because of naturally acidic blackwater inputs at this near-pristine stream
station. We also note that LRC had an unusually high pH level (7.8) in May 2012 (Table
2.3).
Dissolved Oxygen
Dissolved oxygen (DO) problems have been a major water quality concern in the lower
Cape Fear River and its estuary, and several of the tributary streams (Mallin et al. 1999;
2000; 2001a; 2001b; 2002a; 2002b; 2003; 2004; 2005a; 2006a; 2006b; 2007; 2008; 2009;
11
2010; 2011; 2012). Surface concentrations for all sites in 2012 ranged from 0.3 to 12.6
mg/L and station annual means ranged from 3.0 to 9.4 mg/L (Table 2.5). Average annual
DO levels at the river channel and estuarine stations for 2012 were slightly lower than the
average for 1995-2011 (Figure 2.2). River dissolved oxygen levels were lowest during the
summer and early fall (Table 2.5), often falling below the state standard of 5.0 mg/L at
several river and upper estuary stations. Working synergistically to lower oxygen levels
are two factors: lower oxygen carrying capacity in warmer water and increased bacterial
respiration (or biochemical oxygen demand, BOD), due to higher temperatures in summer.
Unlike other large North Carolina estuaries (the Neuse, Pamlico and New River) the Cape
Fear estuary rarely suffers from dissolved oxygen stratification. This is because despite
salinity stratification the oxygen remains well mixed due to strong estuarine gravitational
circulation and high freshwater inputs (Lin et al. 2006). Thus, hypoxia in the Cape Fear is
present throughout the water column.
There is a dissolved oxygen sag in the main river channel that begins at DP below a paper
mill discharge and persists into the mesohaline portion of the estuary (Fig. 2.2). Mean
oxygen levels were highest at the upper river stations NC11 and AC and in the low-to-
middle estuary at stations M35 to M18. Lowest mainstem mean 2012 DO levels occurred
at the river and upper estuary stations IC, NAV, HB, BRR and M61 (6.2-6.6 mg/L). HB,
BRR, DP and M61 were all below 5.0 mg/L on 33% or more of occasions sampled, BBT
was below on 25%, and NCF6 was below on 17% of occasions sampled, a deterioration
from 2011. Based on number of occasions the river stations were below 5 mg/L UNCW
rated HB, BRR, DP and M61 as poor for 2012; the mid to lower estuary stations were rated
as good. Discharge of high BOD waste from the paper/pulp mill just above the AC station
(Mallin et al. 2003), as well as inflow of blackwater from the Northeast Cape Fear and
Black Rivers, helps to diminish oxygen in the lower river and upper estuary. Additionally,
algal blooms periodically form behind Lock and Dam #1 (including the blue-green algal
blooms in recent years), 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 2012 mean = 5.8, NCF6 = 6.3, B210 2012 mean =
6.5) . These rivers are classified as blackwater systems because of their tea colored
water. As the water passes through swamps en route to the river channel, tannins from
decaying vegetation leach into the water, resulting in the observed color. Decaying
vegetation on the swamp floor has an elevated biochemical oxygen demand and usurps
oxygen from the water, leading to naturally low dissolved oxygen levels. Runoff from
concentrated animal feeding operations (CAFOs) may also contribute to chronic low
dissolved oxygen levels in these blackwater rivers (Mallin et al. 1998; 1999; 2006; Mallin
2000). We note that phosphorus and nitrogen (components of animal manure) levels have
been positively correlated with BOD in the blackwater rivers and their major tributaries
(Mallin et al. 2006b).
12
Several stream stations were severely stressed in terms of low dissolved oxygen during
the year 2012. Stations BCRR and SR had DO levels below 4.0 mg/L 67% of the
occasions sampled, with NC403 58%, BC117 50%, LVC2 42%, GS 33% and NCF117 and
SC-CH 25% (Table 2.5). Some of this can be attributed to low summer water conditions
and some potentially to CAFO runoff; however point-source discharges also likely
contribute to low dissolved oxygen levels at NC403 and possibly SR, especially via nutrient
loading (Mallin et al. 2001a; 2002a; 2004). Hypoxia is thus a continuing and widespread
problem, with 47% of the sites impacted in 2012.
Field Turbidity
Field turbidity levels ranged from 0 to 50 Nephelometric turbidity units (NTU) and station
annual means ranged from 1 to 20 NTU (Table 2.6). The State standard for estuarine
turbidity is 25 NTU. Annual mean turbidity levels for 2012 were lower than the long-term
average at all estuary sites (Fig. 2.3), due to reduced river flow. Highest mean turbidities
were at NAV and HB (17-20 NTU) with turbidities generally low in the middle to lower
estuary (Figure 2.3). Stations NAV, HB and BRR exceeded the estuarine turbidity
standard on four, three and two occasions, respectively. Turbidity was considerably lower
in the blackwater tributaries (Northeast Cape Fear River and Black River) than in the
mainstem river. Average turbidity levels were low in the freshwater streams, with the
exception of PB, SR and to a lesser extent LCO. The State standard for freshwater
turbidity is 50 NTU.
Note: In addition to the laboratory-analyzed turbidity that are required my NCDWQ for
seven locations, the LCFRP uses nephelometers designed for field use, which allows us to
acquire in situ turbidity from a natural situation. North Carolina regulatory agencies are
required to use turbidity values from water samples removed from the natural system, put
on ice until arrival at a State-certified laboratory, and analyzed using laboratory
nephelometers. Standard Methods notes that transport of samples and temperature
change alters true turbidity readings. Our analysis of samples using both methods shows
that lab turbidity is nearly always lower than field turbidity; thus we do not discuss lab
turbidity in this report.
Total Suspended Solids
Total suspended solid (TSS) values system wide ranged from 1 to 51 mg/L with station
annual means from 2 to 19 mg/L (Table 2.7). The overall highest river values were at NAV
and M18. In the stream stations TSS was generally considerably lower than the river and
estuary, except for a few incidents at Station PB and Station ROC. 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
13
25 mg/L can be considered elevated. The fine silt and clay in the upper to middle estuary
sediments are most likely derived from the Piedmont and carried downstream to the
estuary, while the sediments in the lowest portion of the estuary are marine-derived sands
(Benedetti et al. 2006).
Light Attenuation
The attenuation of solar irradiance through the water column is measured by a logarithmic
function (k) per meter. The higher this light attenuation coefficient is the more strongly light
is attenuated (through absorbance or reflection) in the water column. River and estuary
light attenuation coefficients ranged from 0.77 to 6.08/m and station annual means ranged
from 1.29 at M18 to 4.17 /m at NCF6 (Table 2.8). Elevated mean and median light
attenuation occurred from AC downstream to IC; the estuary from NAV-M54 also had high
attenuation (Table 2.8). In the Cape Fear system, light is attenuated by both turbidity and
water color.
High light attenuation did not always coincide with high turbidity. Blackwater, though low in
turbidity, will attenuate light through absorption of solar irradiance. At NCF6 and BBT,
blackwater stations with moderate turbidity levels, light attenuation was high. Compared to
other North Carolina estuaries the Cape Fear has high average light attenuation. The high
average light attenuation is a major reason why phytoplankton production in the major
rivers and the estuary of the LCFR is generally low. Whether caused by turbidity or water
color this attenuation tends to limit light availability to the phytoplankton (Mallin et al. 1997;
1999; 2004; Dubbs and Whalen 2008).
Chemical Parameters – Nutrients
Total Nitrogen
Total nitrogen (TN) is calculated from TKN (see below) plus nitrate; it is not analyzed in the
laboratory. TN ranged from 50 (detection limit) to 11,100 g/L and station annual means
ranged from 288 to 2,313 g/L (Table 2.9). Mean total nitrogen in 2012 was less than the
sixteen-year mean at the river and estuary stations (Figure 2.4). Previous research (Mallin
et al. 1999) has shown a positive correlation between river flow and TN in the Cape Fear
system. In the main river total nitrogen concentrations were highest between NC11 and
DP, entering the system, then declined into the lower estuary, most likely reflecting uptake
of nitrogen into the food chain through algal productivity and subsequent grazing by
planktivores as well as through dilution and marsh denitrification. The highest median TN
value at the stream stations was at ROC, with 1,305 g/L; other elevated TN values were
seen at BC117, ANC, GCO and 6RC.
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 11,100 g/L and station annual means ranged from 27 to 1,671 g/L (Table 2.10). The
14
highest average riverine nitrate levels were at NC11 and AC (942 and 890 g/L,
respectively) indicating that much of this nutrient is imported from upstream. Moving
downstream, nitrate levels decrease most likely as a result of uptake by primary producers,
microbial denitrification in riparian marshes and tidal dilution. Despite this, the rapid
flushing of the estuary (Ensign et al. 2004) permits sufficient nitrate to enter the coastal
ocean in the plume and contribute to offshore productivity (Mallin et al. 2005b). Nitrate can
limit phytoplankton production in the lower estuary in summer (Mallin et al. 1999). The
blackwater rivers carried lower concentrations of nitrate compared to the mainstem Cape
Fear stations; i.e. the Northeast Cape Fear River (NCF117 mean = 278 g/L) and the
Black River (B210 = 203 g/L). Lowest river nitrate occurred during summer, along with
lowest flows and lowest dissolved oxygen concentrations.
Several stream stations showed high levels of nitrate on occasion including BC117, ROC,
6RC, GCO, SAR, LVC2 and BRN. 6RC, ROC, GCO and SAR and 6RC primarily receive
non-point agricultural or animal waste drainage. BC117 always showed very high nitrate
levels. The Town of Burgaw wastewater plant, upstream of BC117, has no nitrate
discharge limits. Over the past several years a considerable number of experiments have
been carried out by UNCW researchers to assess the effects of nutrient additions to water
collected from blackwater streams and rivers (i.e. the Black and Northeast Cape Fear
Rivers, and Colly and Great Coharie Creeks). These experiments have collectively found
that additions of nitrogen (as either nitrate, ammonium, or urea) significantly stimulate
phytoplankton production and BOD increases. Critical levels of these nutrients were in the
range of 0.2 to 0.5 mg/L as N (Mallin et al. 1998; Mallin et al. 2001a; Mallin et al. 2002a,
Mallin et al. 2004). Thus, we conservatively consider nitrate concentrations exceeding 0.5
mg/L as N in Cape Fear watershed streams to be potentially problematic to the stream’s
environmental health.
Ammonium/ammonia
Ammonium concentrations ranged from 5 (detection limit) to 3,380 g/L and station annual
means ranged from 5 to 372 g/L (Table 2.11). River areas with the highest mean
ammonium levels this monitoring period included AC and DP, which are downstream of a
pulp mill discharge, and M61, located just upstream of the Wilmington South Side
Wastewater Treatment Plant discharge. Ocean dilution and biological uptake accounts for
decreasing levels in the lower estuary. At the stream stations, areas with highest levels of
ammonium were PB, LVC2, ANC, BC117, BCRR and ROC (Table 2.11). ANC had an
unusually high peak concentration of 3,380 g/L in July for unknown reasons.
Total Kjeldahl Nitrogen
Total Kjeldahl Nitrogen (TKN) is a measure of the total concentration of organic nitrogen
plus ammonium. TKN ranged from 50 (detection limit) to 6,000 g/L and station annual
means ranged from 233 to 1,300 g/L (Table 2.12). TKN concentration decreases ocean-
ward through the estuary, likely due to ocean dilution and food chain uptake of nitrogen.
One notably elevated peak of 6,000 µg/L of TKN was seen at ANC in July; ANC also had
15
the highest median concentrations. Other sites with elevated TKN included ROC, GCO,
SR and COL.
Total Phosphorus
Total phosphorus (TP) concentrations ranged from 10 (detection limit) to 1,400 g/L and
station annual means ranged from 32 to 432 g/L (Table 2.13). Mean TP for 2012 was
somewhat higher than the sixteen-year mean in the estuary and river stations (Figure 2.5).
In the river TP is highest at the upper riverine channel stations NC11 and AC and declines
downstream into the estuary. Some of this decline is attributable to the settling of
phosphorus-bearing suspended sediments, yet incorporation of phosphorus into bacteria
and algae is also responsible.
The experiments discussed above in the nitrate subsection also involved additions of
phosphorus, either as inorganic orthophosphate or a combination of inorganic plus organic
P. The experiments showed that additions of P exceeding 0.5 mg/L led to significant
increases in bacterial counts, as well as significant increases in BOD over control. Thus,
we consider concentrations of phosphorus above 0.5 mg/L (500 g/L) to be potentially
problematic to blackwater streams (Mallin et al. 1998; 2004). Streams periodically
exceeding this critical concentration included BC117, GCO, ROC and NC403. Some of
these stations (BC117, NC403) are downstream of industrial or wastewater discharges,
while GCO and ROC are in non-point agricultural areas.
Orthophosphate
Orthophosphate ranged from undetectable to 1,180 g/L and station annual means ranged
from 6 to 328 g/L (Table 2.14). Much of the orthophosphate load is imported into the
Lower Cape Fear system from upstream areas, as NC11 or AC typically have high levels;
there are also inputs of orthophosphate from the paper mill above AC (Table 2.14). The
Northeast Cape Fear River had higher orthophosphate levels than the Black River.
Orthophosphate can bind to suspended materials and is transported downstream via
particle attachment; thus high levels of turbidity at the uppermost river stations may be an
important factor in the high orthophosphate levels. Turbidity declines toward the lower
estuary because of settling, and orthophosphate concentration also declines. In the
estuary, primary productivity helps reduce orthophosphate concentrations by assimilation
into biomass. Orthophosphate levels typically reach maximum concentrations during
summertime, when anoxic sediment releases bound phosphorus. Also, in the Cape Fear
Estuary, summer algal productivity is limited by nitrogen, thereby allowing the
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 high orthophosphate levels, and ROC and GCO had
comparatively high levels. BC117 is below a municipal wastewater discharge, and ROC
and GCO are impacted by agriculture/animal waste runoff.
16
Chemical Parameters - EPA Priority Pollutant Metals
The LCFRP had previously sampled for water column metals (EPA Priority Pollutant
Metals) on a bimonthly basis. However, as of 2007 this requirement was suspended by
the NC Division of Water Quality and these data are no longer collected by the LCFRP.
Biological Parameters
Chlorophyll a
During this monitoring period in most locations chlorophyll a was low, except for elevated
concentrations in July and August at the river and upper estuary stations (Table 2.15).
The only exceedence of the state standard was for 54 µg/L at Station 61 in August; there
was also a bloom or 40 µg/L at AC in July. We note that at the upper site NC11 it has
been demonstrated that chlorophyll a biomass is significantly correlated with biochemical
oxygen demand (BOD5 – Mallin et al. 2006b). What is of human health concern as well as
ecological interest was that blooms of cyanobacteria (blue-green algae) called Microcystis
aeruginosa began occurring in 2009 and continued to occur in summer 2010, 2011 and
2012. This species contains many strains long known to produce toxins, both as a threat
to aquatic life and to humans as well (Burkholder 2002). At least some of the blooms in
the main stem of the Cape Fear have produced toxins. The North Carolina Division of
Public Health had a 2009 bloom sample from Lock and Dam #1 tested and it came out
positive for 73 ppb (g/L) of microcystin (Dr. Mina Shehee, NC Division of Public Health,
memo September 25, 2011), resulting in an advisory to keep children and dogs from
swimming in the waters. For comparison, the World Health Organization has a guideline
of < 1.0 g/L of microcystin-LR for drinking water. Additional algal bloom material from the
Cape Fear River collected in September 2009 was analyzed by Dr. Paul Zimba at Texas
A&M University-Corpus Christi, who found a water microcystin RR concentration of 391
µg/L. In related work UNCW researchers directed by chemists Dr. Jeff Wright and Dr.
Wendy Strangman also isolated the two hepatotoxins, microcystin LR and microcystin RR,
from Cape Fear Microcystis aeruginosa blooms in 2010 (Isaacs 2011). These researchers
also found two new cyanopeptides, micropeptin 1106 and micropeptin 1120 in elevated
concentrations; the biological activity of those two compounds is unknown. We note that
the City of Wilmington and parts of Brunswick County receive their drinking water from the
river above Lock and Dam #1 in the bloom area.
In 2012 a significant Microcystis aeruginosa bloom occurred in July in the vicinity of Lock
and dam #1. Jared Metheny, a student under the direction of Dr. Mike Mallin found
significant correlations between chlorophyll a and BOD5 in surface and sub-surface water
at Stations NC11 and AC and downstream several miles. Dr. Larry Cahoon, of the UNCW
Biology and Marine Biology Department, also collected a variety of chemical samples in
association with blooms upstream of L&D#1, with the goal of gaining further understanding
of how these blooms affect the river’s ecology.
System wide, chlorophyll a ranged from undetectable to 54 g/L and station annual means
ranged from 2-8 g/L, lower than in 2011. Production of chlorophyll a biomass is usually
17
low to moderate in the rivers and estuary primarily because of light limitation by turbidity in
the mainstem and high organic color and low inorganic nutrients in the blackwater rivers.
Spatially, besides Station NC11 along the mainstem high values are normally found in the
mid-to-lower estuary stations because light becomes more available downstream of the
estuarine turbidity maximum (Fig. 2.6). On average, flushing time of the Cape Fear
estuary is rapid, ranging from 1-22 days with a median of 6.7 days (Ensign et al. 2004).
This does not allow for much settling of suspended materials, leading to light limitation of
phytoplankton production. However, under lower-than-average flows there is generally
clearer water through less suspended material and less blackwater swamp inputs. For the
growing season May-September, long-term (1995-2012) average monthly flow at Lock and
Dam #1 was approximately 3,361 CFS (USGS data;
(http://nc.water.usgs.gov/realtime/real_time_cape_fear.html), whereas for 2012 it was well
below that at approximately 1,719 CFS. Thus, chlorophyll a concentrations in the river and
estuary were mostly greater than the average for the preceding sixteen years (Figure 2.6).
Phytoplankton blooms occasionally occur at the stream stations, with a few occurring at
various months in 2012 (Table 2.15). These streams are generally shallow, so vertical
mixing does not carry phytoplankton cells down below the critical depth where respiration
exceeds photosynthesis. Thus, when lower flow conditions prevail, elevated nutrient
conditions (such as are periodically found in these stream stations) can lead to algal
blooms. In areas where the forest canopy opens up large blooms can occur. When
blooms occur in blackwater streams they can become sources of BOD upon death and
decay, reducing further the low summer dissolved oxygen conditions common to these
waters (Mallin et al. 2001a; 2002a; 2004; 2006b). Stations LRC, PB, NC403 and ANC all
had minor algal blooms in 2012, although not exceeding the state standard of 40 µg/L
(Table 2.15).
Biochemical Oxygen Demand
For the mainstem river, median annual five-day biochemical oxygen demand (BOD5)
concentrations were approximately equivalent between NC11 and AC, suggesting that in
2012 (as was the case with 2007 through 2011) there was little discernable effect of BOD
loading from the nearby pulp/paper mill inputs (Table 2.16). BOD5 values between 1.0
and 2.0 mg/L are typical for the rivers in the Cape Fear system (Mallin et al. 2006b) and in
2012 BOD5 values ranged from 0.3 – 4.2 mg/L. There were no major differences among
sites for BOD5 or BOD20 in 2012. BOD20 values showed similar patterns to BOD5 in
2012.
Fecal Coliform Bacteria/ Enterococcus bacteria
Fecal coliform (FC) bacterial counts ranged from 1 to 60,000 CFU/100 mL and station
annual geometric means ranged from 17 to 602 CFU/100 mL (Table 2.17). The state
human contact standard (200 CFU/100 mL) was exceeded at the mainstem sites only
once in 2012, at HB in September. During 2012 the stream stations showed high fecal
coliform pollution levels. BC117 and HAM exceeded 200 CFU/100 mL 67% of the time;
18
BCRR and BRN 58%, PB and SAR 50%, GS, NC403, ROC, LROC SR and SC-CH 42%,
ANC, GCO and LVC2 33% of the time. BC117, NC403 and PB are located below point
source discharges and the other sites are primarily influenced by non-point source
pollution.
Enterococcus counts were initiated in the estuary in mid-2011, as this test is now the
standard used by North Carolina regulators for swimming in salt waters. Sites covered by
this test include BRR, M61, M54, M35, M23 and M18. The State has a single-sample level
for Tier II swimming areas in which the enterococci level in a Tier II swimming area shall
not exceed a single sample of 276 enterococci per 100 milliliter of water (15A NCAC 18A
.3402); the LCFRP is using this standard for the Cape Fear estuary samples in our rating
system. As such, in 2012 most estuary sites exceeded the standard on two occasions,
yielding a Fair rating by our standards. Overall, elevated fecal coliform and enterococcus
counts are problematic in this system, with 66% of the stations rated as Fair or Poor in
2012, higher than the previous year 2011.
2.4 - References Cited
APHA. 1995. Standard Methods for the Examination of Water and Wastewater, 19th ed.
American Public Health Association, Washington, D.C.
Benedetti, M.M., M.J. Raber, M.S. Smith and L.A. Leonard. 2006. Mineralogical indicators of alluvial sediment sources in the Cape Fear River basin, North Carolina. Physical Geography 27:258-281. Burkholder. J.M. 2002. Cyanobacteria. In “Encyclopedia of Environmental Microbiology” (G. Bitton, Ed.), pp 952-982. Wiley Publishers, New York. Dubbs, L. L. and S.C. Whalen. 2008. Light-nutrient influences on biomass, photosynthetic potential and composition of suspended algal assemblages in the middle Cape Fear River, USA. International Review of Hydrobiology 93:711-730. Ensign, S.H., J.N. Halls and M.A. Mallin. 2004. Application of digital bathymetry data in an analysis of flushing times of two North Carolina estuaries. Computers and Geosciences 30:501-511.
Isaacs, J.D. 2011. Chemical investigations of the metabolites of two strains of toxic cyanobacteria. M.S. Thesis, University of North Carolina Wilmington, Wilmington, N.C. Lin, J. L. Xie, L.J. Pietrafesa, J. Shen, M.A. Mallin and M.J. Durako. 2006. Dissolved oxygen stratification in two microtidal partially-mixed estuaries. Estuarine, Coastal and Shelf Science. 70:423-437.
Mallin, M.A. 2000. Impacts of industrial-scale swine and poultry production on rivers and
estuaries. American Scientist 88:26-37.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1997. Nutrient
limitation and eutrophication potential in the Cape Fear and New River Estuaries.
19
Report No. 313. Water Resources Research Institute of the University of North Carolina,
Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 1998. Effect of organic and
inorganic nutrient loading on photosynthetic and heterotrophic plankton communities in
blackwater rivers. Report No. 315. Water Resources Research Institute of the
University of North Carolina, Raleigh, N.C.
Mallin, M.A., L.B. Cahoon, M.R. McIver, D.C. Parsons and G.C. Shank. 1999. Alternation
of factors limiting phytoplankton production in the Cape Fear Estuary. Estuaries
22:985-996.
Mallin, M.A., M.H. Posey, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S. Williams, M.L.
Moser and J.F. Merritt. 2000. Environmental Assessment of the Lower Cape Fear River
System, 1999-2000. CMS Report No. 00-01, Center for Marine Science, University of
North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., L.B. Cahoon, D.C. Parsons and S.H. Ensign. 2001a. Effect of nitrogen and
phosphorus loading on plankton in Coastal Plain blackwater streams. Journal of
Freshwater Ecology 16:455-466.
Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, S.H. Ensign, T.D. Alphin, M.S.
Williams, M.L. Moser and J.F. Merritt. 2001b. Environmental Assessment of the Lower
Cape Fear River System, 2000-2001. CMS Report No. 01-01, Center for Marine
Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., L.B. Cahoon, M.R. McIver and S.H. Ensign. 2002a. Seeking science-based
nutrient standards for coastal blackwater stream systems. Report No. 341. Water
Resources Research Institute of the University of North Carolina, Raleigh, N.C.
Mallin, M.A., M.H. Posey, T.E. Lankford, M.R. McIver, H.A. CoVan, T.D. Alphin, M.S.
Williams and J.F. Merritt. 2002b. Environmental Assessment of the Lower Cape Fear
River System, 2001-2002. CMS Report No. 02-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver, H.A. Wells, M.S. Williams, T.E. Lankford and J.F. Merritt. 2003.
Environmental Assessment of the Lower Cape Fear River System, 2002-2003. CMS
Report No. 03-03, Center for Marine Science, University of North Carolina at
Wilmington, Wilmington, N.C.
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.
20
Mallin, M.A., L.B. Cahoon and M.J. Durako. 2005b. Contrasting food-web support bases for adjoining river-influenced and non-river influenced continental shelf ecosystems. Estuarine, Coastal and Shelf Science 62:55-62. Mallin, M.A., M.R. McIver and J.F. Merritt. 2006a. Environmental Assessment of the Lower Cape Fear River System, 2005. CMS Report No. 06-02, Center for Marine Science, University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., V.L. Johnson, S.H. Ensign and T.A. MacPherson. 2006b. Factors contributing
to hypoxia in rivers, lakes and streams. Limnology and Oceanography 51:690-701.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2007. Environmental Assessment of the Lower
Cape Fear River System, 2006. CMS Report No. 07-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2008. Environmental Assessment of the Lower
Cape Fear River System, 2007. CMS Report No. 08-03, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2009. Environmental Assessment of the Lower
Cape Fear River System, 2008. CMS Report No. 09-06, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2010. Environmental Assessment of the Lower
Cape Fear River System, 2009. CMS Report No. 10-04, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2011. Environmental Assessment of the Lower
Cape Fear River System, 2010. CMS Report No. 11-02, Center for Marine Science,
University of North Carolina at Wilmington, Wilmington, N.C.
Mallin, M.A., M.R. McIver and J.F. Merritt. 2012. Environmental Assessment of the Lower
Cape Fear River System, 2011. CMS Report No. 12-03, 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.
21
Table 2.0 Lower Cape Fear River Program Parameter Analysis Methods List
LabParameterMethod
UNCW Aquatic Ecology Lab TemperatureSM 2550 B-2000
Dissolved OxygenSM 4500 O G-2001
pHSM 45500 H B-2000
Specific ConductivitySM 2510 B-1997
Chlorophyll a Welschmeyer 1985, EPA 445.0
OrthophosphateEPA 365.5
Commercial Contract LabTotal Suspended SolidsSM 2540 D-1997
Lab TurbiditySM 2130 B-2001
Total Nitrogen by addition, TKN + Nitrate/Nitrite
Nitrate-NitriteEPA 353.2, Rev. 2.0-1993
Ammonia-NSM 4500 NH3 D-1997
Total Kjeldahl NitrogenEPA 351.2, Rev. 2.0-1993
Total PhosphorusSM 4500 P E-1999
Fecal Coliform BacteriaSM 9222 D-1997
EnterococcusEPA 1600, Enterolert IDEXX
22
Table 2.1 Water temperature (oC) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 11.6 12.5 12.4 12.0 12.0 12.7 12.7 12.4 JAN 9.3 9.5 9.8 9.8 9.9 11.5
FEB 12.3 12.2 11.9 12.7 12.3 12.5 12.4 13.0 FEB 10.5 10.8 11.1 11.1 11.2 12.7
MAR 13.8 14.9 14.1 14.4 15.1 14.9 14.6 14.0 MAR 13.4 13.4 13.7 14.0 13.7 14.5
APR 19.4 19.7 19.5 20.0 20.2 20.1 19.5 19.5 APR 20.0 19.9 19.8 19.9 20.2 19.7
MAY 21.7 22.0 22.1 22.0 22.1 22.2 22.4 22.2 MAY 21.9 22.1 22.3 22.3 22.3 22.6
JUN 24.7 24.3 24.6 25.9 25.1 25.1 25.0 25.3 JUN 25.3 25.1 23.5 22.9 23.9 23.8
JUL 30.9 31.0 31.3 30.9 30.6 30.0 29.5 29.6 JUL 30.3 30.5 30.5 30.6 32.0 31.4
AUG 29.6 29.7 29.5 29.4 29.7 29.5 29.7 29.9 AUG 29.2 29.1 29.0 28.3 28.8 28.1
SEP 26.9 27.1 28.3 27.3 27.9 28.4 28.4 28.6 SEP 28.2 28.1 28.4 27.1 27.6 26.9
OCT 25.2 26.0 26.5 25.5 25.7 25.9 26.1 26.5 OCT 22.0 22.1 22.1 21.6 22.4 22.6
NOV 14.5 15.1 14.8 15.0 15.4 15.1 15.2 15.5 NOV 13.8 13.9 14.2 13.0 14.1 14.3
DEC 12.6 12.9 15.0 13.2 12.9 13.2 13.8 13.9 DEC 11.6 11.7 11.6 11.5 11.6 12.5
mean 20.3 20.6 20.8 20.7 20.8 20.8 20.8 20.9 mean 19.6 19.7 19.7 19.3 19.8 20.1
std dev 7.2 7.0 7.1 7.0 7.0 6.9 6.9 6.9 std dev 7.7 7.6 7.4 7.3 7.6 6.8
median 20.6 20.9 20.8 21.0 21.2 21.2 21.0 20.9 median 21.0 21.0 21.0 20.8 21.3 21.2
max 30.9 31.0 31.3 30.9 30.6 30.0 29.7 29.9 max 30.3 30.5 30.5 30.6 32.0 31.4
min 11.6 12.2 11.9 12.0 12.0 12.5 12.4 12.4 min 9.3 9.5 9.8 9.8 9.9 11.5
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 9.6 8.3 9.3 8.7 6.6 10.1 9.0 10.1 9.4 JAN 3.9 4.2 3.3 4.0 4.8 4.8 JAN 10.1 5.6 4.3 7.4 9.9
FEB 9.4 8.4 9.4 8.0 8.0 10.6 8.9 8.8 9.2 FEB 8.5 8.7 9.5 9.2 10.2 10.3 FEB 12.2 12.0 11.5 11.6 13.6
MAR 16.3 15.7 17.3 16.4 16.7 17.5 16.4 13.5 14.3 MAR 13.5 13.5 15.4 14.7 15.2 15.0 MAR 14.1 14.9 14.5 13.9 15.4
APR 17.9 19.0 21.0 18.1 21.3 20.2 17.0 16.0 14.4 APR 14.9 14.9 15.2 16.1 16.3 15.3 APR 17.8 15.6 13.3 16.4 18.5
MAY 24.6 22.5 25.0 23.0 24.2 25.1 22.1 21.4 20.6 MAY 21.7 21.5 21.9 21.5 20.1 20.7 MAY 24.0 23.3 18.9 21.4 24.9
JUN 23.9 24.3 26.2 25.2 27.3 25.6 23.1 22.3 21.8 JUN 24.5 23.7 24.4 23.6 23.0 22.5 JUN 22.3 20.9 18.4 23.3 23.4
JUL 26.1 25.1 28.6 27.7 32.1 28.7 25.8 23.9 24.8 JUL 26.8 26.9 27.3 26.5 26.3 27.0 JUL 29.3 29.5 25.1 27.9 30.1
AUG 23.7 24.2 24.6 25.7 25.5 24.8 23.9 23.8 24.1 AUG 25.9 26.0 25.9 26.0 25.5 25.1 AUG 27.1 26.4 23.9 26.4 29.0
SEP 21.3 21.7 21.2 22.4 23.8 23.3 21.5 20.2 20.3 SEP 19.9 19.6 20.8 20.9 19.4 19.6 SEP 26.2 26.0 23.9 25.8 27.6
OCT 18.0 17.9 17.1 17.0 17.6 17.2 16.1 16.8 16.4 OCT 15.7 15.9 15.8 15.3 16.1 15.9 OCT 22.3 19.0 16.5 19.4 22.5
NOV 9.9 10.0 9.1 9.9 9.4 9.3 10.5 10.3 10.7 NOV 10.6 10.4 10.8 12.4 10.8 10.9 NOV 16.0 13.1 10.6 14.0 16.6
DEC 15.5 16.1 16.4 15.1 16.5 16.4 14.8 15.1 13.5 DEC 10.7 10.6 9.9 9.9 10.3 10.3 DEC 12.4 12.5 10.4 12.2 13.2
mean 18.0 17.8 18.8 18.1 19.1 19.1 17.4 16.9 16.6 mean 16.4 16.3 16.7 16.7 16.5 16.5 mean 19.5 18.2 15.9 18.3 20.4
std dev 6.1 6.2 6.9 6.8 8.1 6.6 5.9 5.5 5.6 std dev 7.4 7.3 7.5 7.1 6.7 6.7 std dev 6.5 7.2 6.4 6.7 6.8
median 18.0 18.5 19.2 17.6 19.5 18.9 16.7 16.4 15.4 median 15.3 15.4 15.6 15.7 16.2 15.6 median 20.1 17.3 15.5 17.9 20.5
max 26.1 25.1 28.6 27.7 32.1 28.7 25.8 23.9 24.8 max 26.8 26.9 27.3 26.5 26.3 27.0 max 29.3 29.5 25.1 27.9 30.1
min 9.4 8.3 9.1 8.0 6.6 9.3 8.9 8.8 9.2 min 3.9 4.2 3.3 4.0 4.8 4.8 min 10.1 5.6 4.3 7.4 9.9
23
Table 2.2 Salinity (psu) during 2012 at the Lower Cape Fear River Program estuarine stations.
NAV HB BRR M61 M54 M35 M23 M18 NCF6 SC-CH
JAN 3.9 3.3 3.8 7.3 15.5 24.4 30.3 35.1 11.9 4.9
FEB 3.9 5.3 7.6 10.8 15.5 24.9 31.2 35.1 0.1 2.5
MAR 0.1 0.2 0.2 3.2 4.3 13.4 20.6 26.7 0.1 2.1
APR 0.1 0.1 0.1 2.7 3.2 7.0 17.5 18.6 7.7 0.9
MAY 0.2 2.9 5.9 11.2 12.5 18.1 24.9 28.2 0.3 8.1
JUN 1.5 2.3 2.4 3.3 9.6 18.6 28.5 32.4 0.6 0.4
JUL 5.1 8.4 12.2 15.3 18.3 25.3 32.4 34.0 2.9 6.3
AUG 3.2 7.2 4.2 6.9 11.1 19.0 28.2 33.5 0.1 1.2
SEP 0.8 1.2 1.2 1.4 4.9 11.8 23.5 28.6 0.1 0.1
OCT 5.4 6.2 4.3 10.1 14.8 21.8 30.1 33.4 0.6 1.2
NOV 7.2 11.3 13.9 17.2 20.8 25.3 30.3 31.9 5.3 10.2
DEC 10.9 13.0 7.4 14.5 18.8 25.8 32.7 34.4 7.2 10.1
mean 3.5 5.1 5.3 8.7 12.4 19.6 27.5 31.0 3.1 4.0
std dev 3.3 4.2 4.4 5.4 5.9 6.2 4.9 4.8 4.0 3.8
median 3.6 4.3 4.3 8.7 13.7 20.4 29.3 32.9 0.6 2.3
max 10.9 13.0 13.9 17.2 20.8 25.8 32.7 35.1 11.9 10.2
min 0.1 0.1 0.1 1.4 3.2 7.0 17.5 18.6 0.1 0.1
24
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25
Table 2.3 Conductivity (mS/cm) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 7.00 5.77 6.93 12.60 25.51 38.40 46.68 53.27 JAN 0.15 0.19 0.24 0.23 0.27 19.93
FEB 7.21 9.43 13.21 18.17 25.41 39.09 47.93 53.26 FEB 0.13 0.19 0.19 0.13 0.16 0.29
MAR 0.18 0.36 0.33 5.92 7.71 22.19 32.85 41.75 MAR 0.13 0.13 0.20 0.12 0.14 0.18
APR 0.14 0.14 0.29 5.07 5.81 12.15 28.33 29.97 APR 0.14 0.15 0.25 0.22 0.24 13.34
MAY 0.36 5.38 10.50 18.81 20.87 29.21 39.13 43.67 MAY 0.13 0.26 0.24 0.16 0.21 0.69
JUN 2.91 4.31 4.40 6.07 16.32 30.09 44.17 49.66 JUN 0.15 0.19 0.15 0.12 0.16 0.70
JUL 9.62 14.10 20.53 25.23 29.68 39.95 49.71 51.84 JUL 0.17 0.28 0.42 0.24 0.33 5.40
AUG 5.91 12.64 7.57 12.12 18.81 30.68 43.50 51.24 AUG 0.14 0.36 0.20 0.14 0.20 0.16
SEP 1.55 2.60 2.33 2.72 8.80 19.91 37.26 44.40 SEP 0.16 0.16 0.24 0.11 0.15 0.12
OCT 9.49 10.69 7.71 17.17 24.32 34.72 46.36 50.87 OCT 0.16 0.24 0.26 0.16 0.21 1.13
NOV 12.64 18.97 22.91 27.85 33.19 39.76 46.62 48.85 NOV 0.19 0.24 0.37 0.23 0.30 9.35
DEC 18.25 21.59 12.81 23.84 30.36 40.33 49.87 52.21 DEC 0.20 0.27 0.31 0.30 0.35 12.54
mean 6.27 8.83 9.13 14.63 20.56 31.37 42.70 47.58 mean 0.16 0.22 0.26 0.18 0.23 5.32
std dev 5.64 7.00 7.29 8.53 9.26 9.23 6.88 6.77 std dev 0.02 0.07 0.08 0.06 0.07 6.82
median 6.45 7.60 7.64 14.89 22.59 32.70 45.27 50.26 median 0.15 0.21 0.24 0.16 0.21 0.91
max 18.25 21.59 22.91 27.85 33.19 40.33 49.87 53.27 max 0.20 0.36 0.42 0.30 0.35 19.93
min 0.14 0.14 0.29 2.72 5.81 12.15 28.33 29.97 min 0.13 0.13 0.15 0.11 0.14 0.12
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 0.14 0.19 0.18 0.74 1.08 0.12 0.14 0.71 0.31 JAN 0.15 0.10 0.20 0.15 0.16 0.23 JAN 0.24 0.14 0.10 0.19 8.68
FEB 0.14 0.18 0.17 0.73 1.59 0.13 0.13 0.27 0.16 FEB 0.14 0.10 0.17 0.13 0.16 0.21 FEB 0.19 0.12 0.10 0.17 4.70
MAR 0.13 0.12 0.10 0.25 0.78 0.10 0.10 0.20 0.17 MAR 0.13 0.09 0.14 0.10 0.15 0.17 MAR 0.17 0.11 0.10 0.17 3.89
APR 0.10 0.16 0.16 0.33 1.72 0.16 0.15 0.25 0.27 APR 0.12 0.08 0.12 0.09 0.12 0.15 APR 0.14 0.09 0.09 0.14 1.70
MAY 0.12 0.18 0.16 0.61 2.16 0.15 0.10 0.25 0.23 MAY 0.13 0.09 0.33 0.11 0.14 0.19 MAY 0.24 0.12 0.08 0.18 13.95
JUN 0.09 0.17 0.17 0.54 2.32 0.10 0.11 0.28 0.22 JUN 0.13 0.08 0.26 0.12 0.12 0.15 JUN 0.10 0.09 0.08 0.13 0.84
JUL 0.18 0.18 0.18 0.61 0.73 0.08 0.11 0.22 0.24 JUL 0.13 0.09 0.23 0.13 0.12 0.14 JUL 0.20 0.13 0.09 0.16 11.16
AUG 0.10 0.14 0.16 0.64 3.99 0.09 0.09 0.11 0.10 AUG 0.14 0.17 0.17 0.12 0.11 0.11 AUG 0.14 0.10 0.08 0.16 2.30
SEP 0.09 0.18 0.21 0.69 5.50 0.10 0.13 0.13 0.07 SEP 0.15 0.10 0.37 0.12 0.13 0.16 SEP 0.10 0.08 0.08 0.11 0.27
OCT 0.11 0.21 0.18 0.72 2.48 0.13 0.16 0.36 0.24 OCT 0.15 0.10 0.56 0.10 0.13 0.17 OCT 0.16 0.09 0.08 0.13 2.32
NOV 0.14 0.22 0.21 1.01 4.64 0.16 0.29 0.26 0.27 NOV 0.16 0.11 0.37 0.13 0.14 0.20 NOV 0.20 0.13 0.07 0.15 17.18
DEC 0.12 0.26 0.24 1.01 4.67 0.16 0.25 0.34 0.33 DEC 0.15 0.11 0.27 0.12 0.13 0.19 DEC 0.18 0.14 0.07 0.17 17.06
mean 0.12 0.18 0.18 0.66 2.64 0.12 0.14 0.28 0.22 mean 0.14 0.10 0.27 0.12 0.13 0.17 mean 0.17 0.11 0.08 0.15 7.00
std dev 0.03 0.04 0.03 0.23 1.65 0.03 0.06 0.15 0.08 std dev 0.01 0.02 0.12 0.02 0.02 0.03 std dev 0.05 0.02 0.01 0.02 6.35
median 0.12 0.18 0.17 0.67 2.24 0.12 0.13 0.26 0.24 median 0.14 0.10 0.25 0.12 0.13 0.17 median 0.17 0.11 0.08 0.16 4.29
max 0.18 0.26 0.24 1.01 5.50 0.16 0.29 0.71 0.33 max 0.16 0.17 0.56 0.15 0.16 0.23 max 0.24 0.14 0.10 0.19 17.18
min 0.09 0.12 0.10 0.25 0.73 0.08 0.09 0.11 0.07 min 0.12 0.08 0.12 0.09 0.11 0.11 min 0.10 0.08 0.07 0.11 0.27
26
Table 2.4 pH during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 7.3 7.3 7.3 7.5 7.8 8.1 8.1 8.1 JAN 7.1 7.3 7.2 7.2 7.2 7.5
FEB 7.4 7.4 7.4 7.6 7.9 8.1 8.1 8.0 FEB 7.0 7.3 7.2 6.6 6.9 7.0
MAR 7.1 7.2 7.2 7.3 7.5 8.0 8.1 8.1 MAR 6.9 6.9 7.1 6.4 6.7 6.6
APR 6.7 6.6 6.9 6.9 7.2 7.4 7.9 7.9 APR 6.7 6.8 6.7 6.8 6.8 7.0
MAY 7.6 7.5 7.1 7.4 7.5 7.7 8.0 8.0 MAY 6.7 6.9 6.7 6.1 6.4 6.5
JUN 6.8 6.9 7.1 7.1 7.4 7.8 8.0 8.1 JUN 6.7 6.9 6.5 6.3 6.6 6.7
JUL 7.1 7.2 7.3 7.4 7.7 7.9 8.0 8.0 JUL 6.9 7.6 7.3 6.9 7.0 6.8
AUG 7.1 7.2 7.2 7.3 7.7 7.9 8.0 8.1 AUG 6.6 7.0 6.7 6.4 6.7 6.5
SEP 6.6 6.7 6.7 6.9 7.3 7.4 7.9 8.0 SEP 6.3 6.6 6.6 5.7 6.2 5.8
OCT 7.3 7.4 7.6 7.4 7.6 7.9 8.1 8.1 OCT 6.5 6.9 6.9 6.3 6.7 6.7
NOV 7.5 7.5 7.6 7.7 7.9 8.0 8.1 8.1 NOV 6.0 6.6 6.8 6.5 6.7 6.7
DEC 7.5 7.6 7.5 7.7 7.9 8.0 8.0 8.0 DEC 6.8 6.6 6.6 6.8 6.9 6.8
mean 7.2 7.2 7.2 7.4 7.6 7.9 8.0 8.0 mean 6.7 7.0 6.9 6.5 6.7 6.7
std dev 0.3 0.3 0.3 0.3 0.2 0.2 0.1 0.1 std dev 0.3 0.3 0.3 0.4 0.3 0.4
median 7.2 7.3 7.3 7.4 7.7 7.9 8.0 8.1 median 6.7 6.9 6.8 6.5 6.7 6.7
max 7.6 7.6 7.6 7.7 7.9 8.1 8.1 8.1 max 7.1 7.6 7.3 7.2 7.2 7.5
min 6.6 6.6 6.7 6.9 7.2 7.4 7.9 7.9 min 6.0 6.6 6.5 5.7 6.2 5.8
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 6.4 6.6 6.8 6.5 6.7 7.2 6.8 7.5 6.8 JAN 6.4 6.5 6.5 6.0 6.5 6.7 JAN 6.9 6.6 3.9 6.5 7.3
FEB 6.4 6.7 6.9 6.7 6.8 7.5 7.0 7.2 6.9 FEB 6.9 6.5 6.5 5.8 6.8 7.2 FEB 6.7 6.2 3.9 7.2 7.1
MAR 5.9 6.0 6.4 6.0 6.5 6.7 6.3 6.6 6.4 MAR 6.7 6.3 6.4 5.8 6.8 6.9 MAR 6.7 6.3 3.9 7.2 7.1
APR 5.2 6.4 6.4 5.9 6.8 7.3 6.8 6.7 6.4 APR 6.3 6.0 6.0 5.8 6.3 6.6 APR 6.4 5.9 3.5 6.5 6.8
MAY 5.9 6.1 6.4 6.3 6.8 7.8 6.5 6.9 6.7 MAY 6.8 6.6 6.9 6.0 6.5 7.0 MAY 6.7 6.2 4.0 6.6 6.8
JUN 4.6 6.5 6.7 6.4 6.9 6.8 6.6 6.9 6.6 JUN 6.7 6.3 6.8 6.3 7.0 7.1 JUN 6.0 5.8 3.7 6.3 6.4
JUL 6.2 6.1 6.6 6.5 6.8 6.8 6.8 6.8 6.6 JUL 6.3 6.4 6.6 6.1 6.7 6.7 JUL 6.6 6.4 4.2 6.8 6.5
AUG 5.6 6.6 6.5 6.5 6.4 6.1 6.0 6.1 6.2 AUG 6.5 6.5 6.2 5.8 6.3 6.4 AUG 6.2 5.9 3.8 6.5 6.6
SEP 5.2 6.5 6.7 6.6 6.8 6.7 6.5 6.0 5.2 SEP 6.1 6.7 7.0 6.4 7.1 6.9 SEP 5.8 5.5 3.7 6.4 6.3
OCT 5.9 6.8 6.6 6.6 6.8 7.1 6.5 6.5 6.0 OCT 5.6 5.8 6.6 5.3 5.8 6.5 OCT 6.3 5.7 3.4 7.0 6.9
NOV 6.5 6.9 7.0 7.0 6.2 6.7 6.6 6.1 5.6 NOV 5.6 6.1 6.2 6.3 6.4 6.6 NOV 6.1 5.7 3.3 6.7 6.3
DEC 6.2 6.8 6.8 6.8 6.6 7.0 6.0 6.1 5.7 DEC 5.6 5.8 6.0 5.7 6.2 6.5 DEC 6.5 6.2 3.3 6.6 7.1
mean 5.8 6.5 6.7 6.5 6.7 7.0 6.5 6.6 6.3 mean 6.3 6.3 6.5 5.9 6.5 6.8 mean 6.4 6.0 3.7 6.7 6.8
std dev 0.6 0.3 0.2 0.3 0.2 0.4 0.3 0.5 0.5 std dev 0.5 0.3 0.3 0.3 0.4 0.3 std dev 0.3 0.3 0.3 0.3 0.3
median 5.9 6.6 6.7 6.5 6.8 6.9 6.6 6.7 6.4 median 6.4 6.4 6.5 5.9 6.5 6.7 median 6.5 6.1 3.8 6.6 6.8
max 6.5 6.9 7.0 7.0 6.9 7.8 7.0 7.5 6.9 max 6.9 6.7 7.0 6.4 7.1 7.2 max 6.9 6.6 4.2 7.2 7.3
min 4.6 6.0 6.4 5.9 6.2 6.1 6.0 6.0 5.2 min 5.6 5.8 6.0 5.3 5.8 6.4 min 5.8 5.5 3.3 6.3 6.3
27
Table 2.5 Dissolved Oxygen (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 10.0 10.4 9.8 9.7 9.4 9.5 9.2 8.7 JAN 10.3 10.1 9.4 9.3 9.2 8.1
FEB 8.2 7.9 7.5 7.7 7.9 8.3 8.6 8.2 FEB 10.7 10.8 10.7 9.8 10.3 9.8
MAR 9.5 9.7 9.5 9.3 9.3 9.8 9.8 9.7 MAR 10.6 10.4 10.0 8.8 9.1 8.2
APR 7.2 6.7 7.7 6.9 7.3 8.0 8.2 8.2 APR 7.1 6.7 5.7 5.6 5.4 6.2
MAY 6.2 6.2 6.2 6.5 6.7 7.0 7.5 7.5 MAY 7.5 7.0 6.5 5.5 6.1 5.9
JUN 4.2 4.0 4.5 4.5 5.1 5.9 6.1 6.0 JUN 6.1 5.7 4.4 4.3 4.3 4.1
JUL 4.3 4.0 4.8 4.6 5.3 5.4 5.5 5.7 JUL 4.5 7.0 4.5 3.8 4.0 5.4
AUG 3.3 3.5 4.4 4.3 5.1 6.0 6.1 6.0 AUG 5.7 6.2 4.8 3.9 4.2 3.7
SEP 3.1 3.2 3.8 3.4 4.4 5.1 5.9 6.4 SEP 5.9 5.6 4.8 3.2 3.6 3.0
OCT 4.7 5.1 5.4 5.0 5.5 5.8 6.1 6.1 OCT 7.0 6.3 5.6 5.0 5.0 5.1
NOV 7.1 7.5 7.4 7.6 8.0 8.4 8.6 8.5 NOV 8.1 8.4 7.7 6.7 6.6 7.4
DEC 8.1 8.2 8.2 8.3 8.5 8.7 8.7 8.6 DEC 9.3 9.1 8.4 8.4 8.1 8.5
mean 6.3 6.4 6.6 6.5 6.9 7.3 7.5 7.5 mean 7.7 7.8 6.9 6.2 6.3 6.3
std dev 2.4 2.4 2.0 2.1 1.8 1.7 1.5 1.4 std dev 2.1 1.9 2.3 2.3 2.3 2.1
median 6.7 6.5 6.8 6.7 7.0 7.5 7.9 7.9 median 7.3 7.0 6.1 5.6 5.8 6.1
max 10.0 10.4 9.8 9.7 9.4 9.8 9.8 9.7 max 10.7 10.8 10.7 9.8 10.3 9.8
min 3.1 3.2 3.8 3.4 4.4 5.1 5.5 5.7 min 4.5 5.6 4.4 3.2 3.6 3.0
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 9.4 9.9 10.2 7.9 9.8 11.5 10.1 4.8 2.1 JAN 12.6 12.4 11.6 6.1 12.6 11.7 JAN 9.4 11.2 10.5 7.0 9.4
FEB 9.8 10.2 10.6 8.3 10.7 12.0 10.3 10.1 7.9 FEB 10.9 10.9 9.0 6.3 11.1 10.8 FEB 9.0 9.9 8.4 7.5 9.3
MAR 7.9 6.3 7.3 5.2 4.8 8.9 5.6 7.1 5.1 MAR 9.4 9.6 7.2 4.7 9.4 9.0 MAR 8.8 8.7 7.5 7.8 9.4
APR 4.2 6.4 4.9 3.6 6.5 10.2 7.5 3.3 0.9 APR 8.8 8.7 6.4 3.2 8.6 8.3 APR 5.5 6.5 6.6 4.1 6.9
MAY 3.4 5.2 4.4 0.3 6.5 9.6 6.1 2.8 0.3 MAY 7.1 7.0 6.3 1.0 7.6 7.3 MAY 4.8 4.8 6.0 3.3 5.6
JUN 4.3 5.2 3.6 1.2 8.9 7.3 5.5 2.0 1.2 JUN 6.5 6.5 5.1 0.4 7.0 6.1 JUN 3.6 4.8 5.0 3.0 4.1
JUL 4.8 4.7 2.7 0.4 8.6 6.9 5.7 3.4 1.0 JUL 5.7 6.2 4.4 0.4 6.5 5.5 JUL 4.0 4.2 3.6 2.6 3.7
AUG 4.0 4.5 3.6 1.2 4.4 7.2 4.9 5.4 4.9 AUG 6.7 6.0 3.8 0.6 7.0 7.5 AUG 3.8 4.4 4.1 2.6 3.7
SEP 4.1 5.1 3.6 0.8 6.4 7.9 6.4 6.6 5.9 SEP 7.7 7.6 6.4 3.7 8.2 6.6 SEP 2.2 3.7 3.2 3.4 3.8
OCT 4.2 7.3 6.1 4.1 8.8 9.8 8.4 2.7 0.8 OCT 9.2 8.9 8.3 4.4 9.2 9.3 OCT 4.0 5.7 5.1 4.7 4.8
NOV 5.0 8.9 6.7 4.8 8.7 10.8 8.9 4.2 1.4 NOV 9.6 9.3 9.3 1.5 9.9 8.1 NOV 6.0 6.3 6.8 4.7 7.2
DEC 3.9 7.9 4.9 2.9 4.6 10.3 7.9 1.6 1.6 DEC 9.6 9.4 7.5 3.8 10.1 8.7 DEC 8.0 8.1 7.0 8.0 8.0
mean 5.4 6.8 5.7 3.4 7.4 9.4 7.3 4.5 2.8 mean 8.7 8.5 7.1 3.0 8.9 8.2 mean 5.8 6.5 6.2 4.9 6.3
std dev 2.3 2.0 2.6 2.8 2.1 1.7 1.9 2.5 2.5 std dev 2.0 2.0 2.2 2.2 1.8 1.8 std dev 2.5 2.4 2.1 2.1 2.3
median 4.3 6.4 4.9 3.3 7.6 9.7 7.0 3.8 1.5 median 9.0 8.8 6.8 3.5 8.9 8.2 median 5.2 6.0 6.3 4.4 6.3
max 9.8 10.2 10.6 8.3 10.7 12.0 10.3 10.1 7.9 max 12.6 12.4 11.6 6.3 12.6 11.7 max 9.4 11.2 10.5 8.0 9.4
min 3.4 4.5 2.7 0.3 4.4 6.9 4.9 1.6 0.3 min 5.7 6.0 3.8 0.4 6.5 5.5 min 2.2 3.7 3.2 2.6 3.7
28
0123456789
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Dissolved Oxygen (mg/L)
Fi
g
u
r
e
2
.
2
D
i
s
s
o
l
v
e
d
O
x
y
g
e
n
a
t
t
h
e
L
o
w
e
r
C
a
pe
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
1
v
e
r
s
u
s
2
0
1
2
.
1995-2011 2012
29
Table 2.6 Field Turbidity (NTU) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 16 11 9 8 8 4 4 7 JAN 14 11 13 11 16 19
FEB 17 16 13 8 10 6 6 11 FEB 16 16 18 8 12 12
MAR 29 42 29 13 14 6 7 10 MAR 18 20 22 9 14 16
APR 32 29 25 14 14 7 13 7 APR 20 14 12 9 8 13
MAY 46 15 10 7 8 10 7 10 MAY 16 15 15 9 12 32
JUN 13 17 38 10 12 8 7 7 JUN 14 12 9 7 12 12
JUL 13 12 11 9 10 8 11 8 JUL 23 31 28 8 12 7
AUG 21 7 15 6 4 2 1 1 AUG 24 25 18 5 12 9
SEP 11 9 7 5 3 0 2 2 SEP 37 27 19 10 11 9
OCT 8 5 6 4 6 3 2 5 OCT 35 32 23 12 14 14
NOV 30 34 34 19 19 16 10 12 NOV 10 5 8 2 3 2
DEC 7 6 4 4 4 2 3 4 DEC 6 6 5 4 10 6
mean 20 17 17 9 9 6 6 7 mean 19 18 16 8 11 13
std dev 12 12 12 5 5 4 4 3 std dev 9 9 7 3 3 8
median 17 14 12 8 9 6 7 7 median 17 16 17 9 12 12
max 46 42 38 19 19 16 13 12 max 37 32 28 12 16 32
min 7 5 4 4 3 0 1 1 min 6 5 5 2 3 2
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 4 2 6 1 5 5 4 8 8 JAN 3 3 2 2 3 3 JAN 8 4 2 5 8
FEB 11 3 2 1 7 6 7 14 16 FEB 7 5 3 2 7 5 FEB 3 2 1 2 9
MAR 4 4 3 2 17 9 6 12 9 MAR 7 7 4 2 6 8 MAR 3 3 1 2 7
APR 5 5 6 2 10 3 5 22 7 APR 7 5 3 2 7 5 APR 4 3 1 5 22
MAY 11 3 3 10 6 2 10 11 13 MAY 5 6 3 6 7 5 MAY 6 3 0 5 10
JUN 9 5 3 7 11 12 39 9 6 JUN 5 36 19 47 15 8 JUN 4 3 2 4 31
JUL 10 10 JUL 12 1 11 44 12 4 JUL 6 2 2 5 11
AUG 6 6 4 13 15 20 22 38 20 AUG 15 50 32 49 16 21 AUG 3 2 0 1 14
SEP 6 10 9 15 18 7 14 10 9 SEP 5 1 6 30 2 3 SEP 1 1 0 1 4
OCT 6 7 4 5 12 5 5 10 14 OCT 9 4 4 27 6 8 OCT 2 0 0 1 6
NOV 1 0 1 0 15 1 1 7 7 NOV 0 0 0 4 0 3 NOV 5 2 1 3 18
DEC 4 3 2 7 36 3 7 16 14 DEC 3 1 2 0 0 3 DEC 3 0 0 1 34
mean 6 5 4 6 14 7 11 14 11 mean 7 10 7 18 7 6 mean 4 2 1 3 15
std dev 3 3 2 5 9 5 11 9 4 std dev 4 16 9 20 5 5 std dev 2 1 1 2 10
median 6 5 3 5 12 5 7 11 9 median 6 5 4 5 7 5 median 4 2 1 3 11
max 11 10 9 15 36 20 39 38 20 max 15 50 32 49 16 21 max 8 4 2 5 34
min 1 0 1 0 5 1 1 7 6 min 0 0 0 0 0 3 min 1 0 0 1 4
30
051015202530
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Field Turbidity (NTU)
Fi
g
u
r
e
2
.
3
F
i
e
l
d
T
u
r
b
i
d
i
t
y
a
t
t
h
e
L
o
w
e
r
C
a
pe
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
1
v
e
r
s
u
s
2
0
1
2
.
1995-2011 2012
31
Table 2.7 Total Suspended Solids (mg/L) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 17 18 9 9 15 12 11 16 JAN 5 4 6 12 26
FEB 14 13 13 9 16 13 16 17 FEB 5 6 10 5 10
MAR 26 28 24 12 16 10 15 18 MAR 9 10 12 7 9
APR 27 20 14 10 11 8 22 7 APR 13 7 6 5 12
MAY 29 13 10 11 8 15 14 22 MAY 9 6 10 7 33
JUN 10 10 10 7 16 16 15 10 JUN 8 8 6 6 8
JUL 13 12 13 16 17 15 22 36 JUL 7 14 22 15 8
AUG 19 16 20 12 13 13 18 15 AUG 18 15 14 11 15
SEP 12 14 11 9 9 8 13 16 SEP 20 9 7 5 6
OCT 16 12 12 12 14 13 18 18 OCT 14 10 10 9 8
NOV 29 27 24 26 25 20 19 24 NOV 7 5 7 5 9
DEC 13 18 11 11 13 13 17 24 DEC 4 6 5 11 10
mean 19 17 14 12 14 13 17 19 mean 10 8 10 8 13
std dev 7 6 5 5 4 3 3 7 std dev 5 3 5 3 8
median 16 15 12 11 14 13 17 17 median 8 7 9 7 9
max 29 28 24 26 25 20 22 36 max 20 15 22 15 33
min 10 10 9 7 8 8 11 7 min 4 4 5 5 6
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 1 1 4 5 3 8 6 JAN 1 JAN 5 1 1
FEB 1 1 4 8 5 7 8 FEB 1 FEB 3 1 1
MAR 1 1 10 8 4 6 4 MAR 4 MAR 3 2 1
APR 5 1 8 2 1 19 4 APR 3 APR 4 3 3
MAY 1 12 11 2 9 6 7 MAY 1 MAY 4 1 3
JUN 7 7 8 12 40 6 7 JUN 11 JUN 4 1 1
JUL 9 10 31 7 23 8 6 JUL 6 JUL 5 1 1
AUG 3 9 6 14 12 22 10 AUG 14 AUG 6 1 2
SEP 7 22 9 3 4 5 4 SEP 1 SEP 4 1 1
OCT 3 1 4 2 1 3 14 OCT 1 OCT 6 2 2
NOV 1 2 51 1 1 3 8 NOV 1 NOV 2 1 1
DEC 1 3 17 2 1 4 6 DEC 6 DEC 5 1 1
mean 3 6 14 5 9 8 7 mean 4 mean 4 2 2
std dev 3 6 14 4 12 6 3 std dev 4 std dev 1 1 1
median 2 2 9 4 4 6 6 median 2 median 4 1 1
max 9 22 51 14 40 22 14 max 14 max 6 3 3
min 1 1 4 1 1 3 4 min 1 min 2 1 1
32
Table 2.8 Light Attenuation (k) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 2.95 2.59 2.33 2.33 1.82 1.14 0.88 0.98 JAN
FEB 2.58 2.74 2.48 1.87 1.87 1.00 0.77 0.93 FEB 2.30 2.30 2.28 2.19 2.36 3.91
MAR 3.24 4.41 3.40 2.37 2.55 1.59 1.60 1.26 MAR 2.48 2.81 3.11 3.04 3.02 3.50
APR 3.72 3.85 3.62 3.04 3.10 2.48 1.88 1.53 APR 2.70 2.35 3.15 3.31 3.20 3.60
MAY 3.00 2.58 2.55 2.09 1.95 1.31 1.88 MAY 2.28 2.32 2.17 3.20 2.50 6.08
JUN 4.18 4.31 3.47 3.68 2.82 1.88 1.33 1.07 JUN 2.69 2.51 3.65 3.92 3.54 3.79
JUL 2.65 2.31 2.38 2.18 2.28 1.56 1.46 1.08 JUL 1.99 3.41 3.84 3.22 2.81 3.58
AUG AUG 3.29 4.02 2.92 3.04 2.70 4.29
SEP 5.12 4.64 4.16 3.82 3.22 2.21 1.90 1.54 SEP 3.65 2.68 3.61 4.18 4.27 4.68
OCT 3.25 2.70 2.93 2.66 2.42 1.81 1.29 1.20 OCT 2.84 3.02 3.09 3.72 3.28 4.33
NOV 4.91 4.05 4.60 3.26 2.70 2.31 1.50 1.39 NOV 2.16 2.04 2.95 3.64 3.22 4.00
DEC 3.05 2.80 2.85 2.40 2.33 1.45 1.24 1.36 DEC 1.71 1.89 3.11 2.78 3.55 4.07
mean 3.57 3.40 3.16 2.74 2.47 1.76 1.38 1.29 mean 2.55 2.67 3.08 3.29 3.13 4.17
std dev 0.90 0.85 0.75 0.63 0.46 0.47 0.35 0.28 std dev 0.57 0.62 0.52 0.56 0.54 0.73
max 5.12 4.64 4.60 3.82 3.22 2.48 1.90 1.88 max 3.65 4.02 3.84 4.18 4.27 6.08
min 2.58 2.31 2.33 1.87 1.82 1.00 0.77 0.93 min 1.71 1.89 2.17 2.19 2.36 3.50
33
Table 2.9 Total Nitrogen (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 1,290 1,690 1,320 1,190 1,010 690 430 330 JAN 1,140 1,230 770 1,170 960
FEB 1,030 1,070 1,030 910 690 200 170 50 FEB 1,030 1,080 1,080 770 490
MAR 1,440 1,480 1,330 1,140 1,240 870 760 540 MAR 1,490 1,570 1,300 1,270 1,370
APR 1,150 1,110 1,170 1,240 1,290 1,090 770 730 APR 810 800 610 490 280
MAY 1,640 1,360 1,200 860 840 670 430 340 MAY 1,080 1,270 1,390 1,280 930
JUN 940 920 850 890 890 700 450 400 JUN 1,380 1,340 1,040 1,020 720
JUL 580 560 560 300 400 200 300 300 JUL 630 720 840 780 600
AUG 980 900 950 790 790 340 300 50 AUG 1,420 1,370 1,320 990 900
SEP 960 810 680 690 700 260 200 50 SEP 980 950 750 740 570
OCT 800 600 960 760 690 460 100 140 OCT 1,860 1,800 1,330 1,060 680
NOV 1,070 780 640 1,050 500 810 3,110 470 NOV 1,730 1,820 1,590 1,520 660
DEC 430 340 460 550 620 160 50 50 DEC 1,450 1,230 930 870 350
mean 1,026 968 929 864 805 538 589 288 mean 1,250 1,265 1,079 997 709
std dev 338 397 296 274 270 309 826 225 std dev 368 351 306 286 299
median 1,005 910 955 875 745 565 365 315 median 1,260 1,250 1,060 1,005 670
max 1,640 1,690 1,330 1,240 1,290 1,090 3,110 730 max 1,860 1,820 1,590 1,520 1,370
min 430 340 460 300 400 160 50 50 min 630 720 610 490 280
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 760 480 100 560 150 260 990 11,100 1,030 JAN 940 510 820 330 530 200 JAN 610 630 400 650
FEB 2,180 850 420 710 460 550 1,160 2,870 1,110 FEB 590 370 360 1,210 560 50 FEB 570 370 300 250
MAR 1,530 970 710 550 620 890 1,010 1,680 610 MAR 1,440 960 640 850 770 1,080 MAR 700 550 480 360
APR 670 120 50 260 50 130 980 340 50 APR 1,410 850 860 1,060 700 990 APR 1,150 880 1,000 680
MAY 1,130 580 500 720 700 530 1,160 1,830 850 MAY 1,110 890 1,890 840 710 330 MAY 800 620 730 790
JUN 1,450 1,060 730 1,130 1,180 740 2,480 620 1,030 JUN 1,380 1,150 1,120 1,430 680 800 JUN 1,250 890 940 1,030
JUL 6,530 970 830 1,050 890 1,050 1,450 1,210 780 JUL 1,080 810 1,310 1,470 940 700 JUL 600 500 1,100 690
AUG 1,220 990 560 630 830 940 1,150 1,360 860 AUG 970 1,120 980 1,140 550 940 AUG 750 590 940 640
SEP 1,230 790 540 630 790 580 1,810 710 480 SEP 970 780 1,340 860 510 500 SEP 640 660 750 340
OCT 920 690 600 370 530 480 2,420 500 400 OCT 1,670 580 690 700 380 860 OCT 690 730 720 560
NOV 640 640 300 450 530 440 8,550 710 300 NOV 1,090 420 850 880 830 1,800 NOV 1,180 640 900 420
DEC 480 340 50 530 640 250 4,590 470 120 DEC 1,130 670 730 320 430 230 DEC 790 460 700 400
mean 1,562 707 449 633 614 570 2,313 1,950 635 mean 1,148 759 966 924 633 707 mean 811 627 747 568
std dev 1,634 290 270 252 309 289 2,223 2,974 364 std dev 287 256 403 368 167 486 std dev 243 154 249 223
median 1,175 740 520 595 630 540 1,305 960 695 median 1,100 795 855 870 620 750 median 725 625 740 600
max 6,530 1,060 830 1,130 1,180 1,050 8,550 11,100 1,110 max 1,670 1,150 1,890 1,470 940 1,800 max 1,250 890 1,100 1,030
min 480 120 50 260 50 130 980 340 50 min 590 370 360 320 380 50 min 570 370 300 250
34
0
20
0
40
0
60
0
80
0
1,
0
0
0
1,
2
0
0
1,
4
0
0
1,
6
0
0
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
B
2
1
0
N
C
F
6
Total Nitrogen (g/L)
Fi
g
u
r
e
2
.
4
T
o
t
a
l
N
i
t
r
o
g
e
n
a
t
t
h
e
L
o
w
e
r
C
a
p
e
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
1
v
e
r
s
u
s
2
0
1
2
.
1995-2011 2012
35
Table 2.10 Nitrate/Nitrite (mg/l) during 2012 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 790 1290 820 690 510 390 130 30 JAN 840 1030 470 870 560
FEB 530 570 530 410 390 200 70 10 FEB 1030 980 980 770 290
MAR 640 780 730 540 540 370 260 140 MAR 690 670 600 470 470
APR 450 410 470 440 390 390 270 230 APR 810 800 610 490 280
MAY 1140 960 800 560 540 370 230 140 MAY 880 870 1090 980 330
JUN 340 320 350 290 290 200 50 10 JUN 980 840 440 420 220
JUL 80 60 60 10 10 10 10 10 JUL 30 20 40 80 10
AUG 580 400 450 390 290 140 10 10 AUG 1020 870 1020 690 300
SEP 560 310 280 290 300 260 200 50 SEP 780 650 550 340 107
OCT 500 200 560 460 390 260 100 40 OCT 1460 1400 1030 660 280
NOV 670 480 440 350 300 210 110 70 NOV 1330 1320 1290 920 160
DEC 430 340 460 350 320 160 50 10 DEC 1450 1230 530 870 250
mean 559 510 496 398 356 247 124 63 mean 942 890 721 630 271
std dev 256 346 218 169 145 118 94 71 std dev 387 365 358 273 147
median 545 405 465 400 355 235 105 35 median 930 870 605 675 280
max 1,140 1,290 820 690 540 390 270 230 max 1,460 1,400 1,290 980 560
min 80 60 60 10 10 10 10 10 min 30 20 40 80 10
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 260 180 10 360 50 60 690 11100 330 JAN 740 210 520 130 330 10 JAN 210 330 10 350
FEB 980 350 20 410 60 50 560 1770 510 FEB 490 270 260 1010 560 10 FEB 370 270 10 250
MAR 430 270 210 150 20 290 410 680 310 MAR 840 360 40 50 170 280 MAR 400 350 80 160
APR 70 120 10 260 30 130 980 140 50 APR 610 150 60 60 100 190 APR 250 180 10 180
MAY 130 80 10 20 10 30 560 1030 250 MAY 810 490 1290 40 310 130 MAY 300 220 30 390
JUN 150 260 30 130 80 40 1380 120 30 JUN 880 550 220 130 180 200 JUN 450 190 40 330
JUL 530 270 30 50 90 50 650 410 80 JUL 380 310 210 70 240 200 JUL 10 10 10 90
AUG 120 190 60 30 130 340 450 460 260 AUG 570 220 80 40 150 240 AUG 250 190 40 340
SEP 130 190 40 30 90 80 1110 210 80 SEP 670 380 740 60 310 100 SEP 140 160 50 140
OCT 120 290 10 170 30 180 1920 100 10 OCT 1070 280 290 100 180 360 OCT 190 230 20 160
NOV 140 340 10 250 30 140 7450 310 10 NOV 890 220 250 80 430 10 NOV 480 140 10 220
DEC 80 240 10 230 40 50 3890 270 20 DEC 730 370 230 120 130 30 DEC 290 160 10 200
mean 262 232 38 174 55 120 1,671 1,383 162 mean 723 318 349 158 258 147 mean 278 203 27 234
std dev 268 82 57 131 36 103 2,063 3,098 165 std dev 192 119 356 270 136 117 std dev 135 90 22 97
median 135 250 15 160 45 70 835 360 80 median 735 295 240 75 210 160 median 270 190 15 210
max 980 350 210 410 130 340 7,450 11,100 510 max 1,070 550 1,290 1,010 560 360 max 480 350 80 390
min 70 80 10 20 10 30 410 100 10 min 380 150 40 40 100 10 min 10 10 10 90
36
Table 2.11 Ammonia (mg/l) during 2012 at the Lower Cape Fear River stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 60 60 40 110 80 30 5 5 JAN 40 60 90 80 110
FEB 50 70 70 80 100 20 5 5 FEB 40 80 70 60 70
MAR 20 40 40 60 150 50 20 10 MAR 50 60 150 80 60
APR 90 70 70 70 60 70 30 10 APR 100 90 130 100 80
MAY 90 90 100 90 90 50 10 5 MAY 80 160 100 80 5
JUN 80 70 70 70 100 70 20 5 JUN 50 70 80 60 10
JUL 50 90 110 130 90 20 5 5 JUL 130 90 230 70 40
AUG 30 20 10 20 10 5 5 5 AUG 50 130 40 30 20
SEP 120 100 220 140 70 70 140 500 SEP 110 180 110 70 70
OCT 170 20 100 290 70 140 20 290 OCT 170 50 140 120 50
NOV 20 120 100 120 20 20 70 20 NOV 50 120 100 70 50
DEC 150 100 150 120 70 50 15 15 DEC 20 100 70 120 50
mean 78 71 90 108 76 50 29 73 mean 74 99 109 78 51
std dev 49 32 55 67 37 36 39 157 std dev 45 41 49 26 30
median 70 70 85 100 75 50 18 8 median 50 90 100 75 50
max 170 120 220 290 150 140 140 500 max 170 180 230 120 110
min 20 20 10 20 10 5 5 5 min 20 50 40 30 5
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 10 20 20 40 50 50 50 30 810 JAN 10 10 10 20 10 5 JAN 10 10 10 130
FEB 60 10 10 20 10 10 40 380 130 FEB 30 40 20 30 20 20 FEB 30 20 20 110
MAR 110 40 70 40 120 130 80 330 80 MAR 40 20 20 10 30 50 MAR 10 10 5 110
APR 80 20 10 30 100 50 50 140 120 APR 30 30 20 50 20 80 APR 40 30 10 110
MAY 120 30 5 110 40 30 40 300 560 MAY 30 30 40 130 60 80 MAY 30 40 50 130
JUN 170 50 20 200 90 30 130 140 110 JUN 40 100 130 260 40 50 JUN 50 10 30 130
JUL 3,380 40 10 420 120 100 110 170 160 JUL 80 30 110 310 60 60 JUL 10 30 180 100
AUG 140 120 90 310 510 190 190 230 140 AUG 30 50 60 170 30 60 AUG 30 20 20 100
SEP 140 90 70 260 210 90 140 140 90 SEP 50 50 120 280 20 70 SEP 40 180 250 180
OCT 20 20 70 50 70 100 100 20 170 OCT 70 100 120 100 20 70 OCT 170 100 120 170
NOV 60 30 30 80 100 30 40 170 30 NOV 20 20 100 120 50 70 NOV 150 50 120 150
DEC 170 50 20 50 270 50 20 100 50 DEC 20 70 50 20 50 20 DEC 20 50 50 270
mean 372 43 35 134 141 72 83 179 204 mean 38 46 67 125 34 53 mean 49 46 72 141
std dev 949 32 30 132 137 52 52 112 234 std dev 21 30 46 108 17 25 std dev 54 49 79 48
median 115 35 20 65 100 50 65 155 125 median 30 35 55 110 30 60 median 30 30 40 130
max 3380 120 90 420 510 190 190 380 810 max 80 100 130 310 60 80 max 170 180 250 270
min 10 10 5 20 10 10 20 20 30 min 10 10 10 10 10 5 min 10 10 5 100
37
Table 2.12 Total Kjeldahl Nitrogen (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 500 400 500 500 500 300 300 300 JAN 300 200 300 300 400
FEB 500 500 500 500 300 50 100 50 FEB 50 100 100 50 200
MAR 800 700 600 600 700 500 500 400 MAR 800 900 700 800 900
APR 700 700 700 800 900 700 500 500 APR 50 50 50 50 50
MAY 500 400 400 300 300 300 200 200 MAY 200 400 300 300 600
JUN 600 600 500 600 600 500 400 400 JUN 400 500 600 600 500
JUL 500 500 500 300 400 200 300 300 JUL 600 700 800 700 600
AUG 400 500 500 400 500 200 300 50 AUG 400 500 300 300 600
SEP 400 500 400 400 400 50 50 50 SEP 2000 300 200 400 400
OCT 300 400 400 300 300 200 50 100 OCT 400 400 300 400 400
NOV 400 300 200 700 200 600 3000 400 NOV 400 500 300 600 500
DEC 50 50 50 200 300 50 50 50 DEC 50 50 400 50 50
mean 471 463 438 467 450 304 479 233 mean 471 383 363 379 433
std dev 191 177 172 183 202 223 811 170 std dev 532 261 229 256 245
median 500 500 500 450 400 250 300 250 median 400 400 300 350 450
max 800 700 700 800 900 700 3,000 500 max 2,000 900 800 800 900
min 50 50 50 200 200 50 50 50 min 50 50 50 50 50
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 500 300 100 200 100 200 300 50 700 JAN 200 300 300 200 200 200 JAN 400 300 400 300
FEB 1200 500 400 300 400 500 600 1100 600 FEB 100 100 100 200 50 50 FEB 200 100 300 50
MAR 1100 700 500 400 600 600 600 1000 300 MAR 600 600 600 800 600 800 MAR 300 200 400 200
APR 600 50 50 50 50 50 50 200 50 APR 800 700 800 1000 600 800 APR 900 700 1000 500
MAY 1000 500 500 700 700 500 600 800 600 MAY 300 400 600 800 400 200 MAY 500 400 700 400
JUN 1300 800 700 1000 1100 700 1100 500 1000 JUN 500 600 900 1300 500 600 JUN 800 700 900 700
JUL 6000 700 800 1000 800 1000 800 800 700 JUL 700 500 1100 1400 700 500 JUL 600 500 1100 600
AUG 1100 800 500 600 700 600 700 900 600 AUG 400 900 900 1100 400 700 AUG 500 400 900 300
SEP 1100 600 500 600 700 500 700 500 400 SEP 300 400 600 800 200 400 SEP 500 500 700 200
OCT 800 400 600 200 500 300 500 400 400 OCT 600 300 400 600 200 500 OCT 500 500 700 400
NOV 500 300 300 200 500 300 1100 400 300 NOV 200 200 600 800 400 1800 NOV 700 500 900 200
DEC 400 100 50 300 600 200 700 200 100 DEC 400 300 500 200 300 200 DEC 500 300 700 200
mean 1,300 479 417 463 563 454 646 571 479 mean 425 442 617 767 379 563 mean 533 425 725 338
std dev 1,512 255 247 317 289 261 293 343 273 std dev 218 227 279 410 197 463 std dev 197 182 253 190
median 1,050 500 500 350 600 500 650 500 500 median 400 400 600 800 400 500 median 500 450 700 300
max 6,000 800 800 1,000 1,100 1,000 1,100 1,100 1,000 max 800 900 1,100 1,400 700 1,800 max 900 700 1,100 700
min 400 50 50 50 50 50 50 50 50 min 100 100 100 200 50 50 min 200 100 300 50
38
Table 2.13 Total Phosphorus (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP IC NCF6
JAN 80 110 90 80 70 10 10 10 JAN 120 150 140 130 60
FEB 140 110 140 80 160 100 10 70 FEB 180 180 140 120 80
MAR 180 170 180 160 110 60 50 80 MAR 110 160 130 90 140
APR 140 120 160 90 100 80 50 50 APR 240 190 160 150 110
MAY 310 210 160 90 110 120 110 80 MAY 230 250 260 220 230
JUN 120 110 120 110 110 80 50 40 JUN 180 170 140 140 120
JUL 150 130 100 130 100 60 50 60 JUL 180 190 250 180 70
AUG 150 150 190 150 130 80 40 30 AUG 260 320 240 190 180
SEP 140 140 150 110 120 80 70 30 SEP 220 160 160 110 140
OCT 110 110 110 80 90 50 30 OCT 280 300 280 200 140
NOV 170 130 100 100 70 60 30 30 NOV 260 240 290 170 80
DEC 100 90 90 120 70 40 30 30 DEC 280 260 220 220 70
mean 149 132 133 108 103 70 46 45 mean 212 214 201 160 160
std dev 56 31 34 26 26 28 26 22 std dev 56 55 59 41 50
median 140 125 130 105 105 80 50 35 median 225 190 190 160 115
max 310 210 190 160 160 120 110 80 max 280 320 290 220 220
min 80 90 90 80 70 10 10 10 min 110 150 130 90 90
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 60 40 40 10 110 40 120 1,400 520 JAN 30 10 140 10 30 60 JAN 50 60 10 10
FEB 150 120 170 130 170 120 140 330 110 FEB 60 40 220 10 60 50 FEB 80 60 10 30
MAR 130 40 110 90 380 120 150 620 100 MAR 60 40 290 70 60 50 MAR 40 50 40 70
APR 120 110 80 70 210 110 300 470 340 APR 80 40 280 60 80 130 APR 100 90 70 40
MAY 140 120 120 840 290 50 250 340 350 MAY 160 170 740 120 190 270 MAY 110 130 40 60
JUN 180 180 200 380 220 110 550 270 160 JUN 100 170 680 120 110 200 JUN 120 90 10 50
JUL 710 140 220 630 260 80 310 350 210 JUL 150 60 650 120 190 140 JUL 110 140 60 70
AUG 360 140 140 380 180 130 320 400 170 AUG 150 750 680 130 120 180 AUG 170 140 60 40
SEP 320 210 150 300 160 100 370 230 60 SEP 140 100 420 130 120 200 SEP 160 110 30 30
OCT 180 100 80 160 150 90 280 230 210 OCT 140 50 340 70 70 150 OCT 120 80 30 30
NOV 220 40 40 90 70 40 800 180 120 NOV 70 50 440 70 70 120 NOV 80 60 10 20
DEC 150 80 40 130 270 30 500 300 200 DEC 70 30 300 20 50 80 DEC 50 40 10 10
mean 227 110 116 268 206 85 341 427 213 mean 101 126 432 78 96 136 mean 99 88 32 38
std dev 166 52 60 242 81 35 187 315 126 std dev 43 195 197 45 50 66 std dev 40 34 22 20
median 165 115 115 145 195 95 305 335 185 median 90 50 380 70 75 135 median 105 85 30 35
max 710 210 220 840 380 130 800 1,400 520 max 160 750 740 130 190 270 max 170 140 70 70
min 60 40 40 10 70 30 120 180 60 min 30 10 140 10 30 50 min 40 40 10 10
39
050
10
0
15
0
20
0
25
0
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
Total Phosphorus (g/L)
Fi
g
u
r
e
2
.
5
T
o
t
a
l
P
h
o
s
p
h
o
r
u
s
a
t
t
h
e
L
o
w
e
r
C
a
pe
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
1
v
e
r
s
u
s
2
0
1
2
.
1995-2011 2012
40
Table 2.14 Orthophosphate (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 60 50 50 50 40 20 10 10 JAN 100 100 80 60 70 30
FEB 50 50 50 50 40 20 10 10 FEB 110 100 80 30 60 20
MAR 50 60 60 40 50 30 20 10 MAR 50 50 60 20 40 50
APR 40 40 50 50 50 40 30 20 APR 80 70 60 50 70 40
MAY 90 90 70 60 50 40 20 20 MAY 90 110 120 70 110 50
JUN 50 50 60 50 50 30 10 20 JUN 80 80 50 50 50 50
JUL 70 60 50 50 40 30 20 10 JUL 100 110 150 70 110 30
AUG 70 60 50 70 60 40 10 10 AUG 90 130 120 60 90 70
SEP 50 60 60 60 60 50 30 20 SEP 80 80 80 30 50 60
OCT 40 50 50 50 50 30 20 10 OCT 150 170 130 50 80 60
NOV 70 50 40 50 50 30 20 10 NOV 180 170 170 70 110 40
DEC 50 40 60 50 30 30 10 10 DEC 200 160 130 100 130 30
mean 58 55 54 53 48 33 18 13 mean 109 111 103 55 81 44
std dev 15 13 8 8 9 9 8 5 std dev 45 40 39 22 29 15
median 50 50 50 50 50 30 20 10 median 95 105 100 55 75 45
max 90 90 70 70 60 50 30 20 max 200 170 170 100 130 70
min 40 40 40 40 30 20 10 10 min 50 50 50 20 40 20
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 40 10 10 30 40 0 60 990 250 JAN 10 10 180 10 10 30 JAN 20 20 0 0
FEB 110 10 10 30 20 0 60 240 40 FEB 10 10 180 10 10 30 FEB 20 20 0 0
MAR 90 30 30 50 70 10 60 410 40 MAR 20 10 190 0 10 30 MAR 20 20 0 0
APR 50 30 20 50 40 10 90 170 50 APR 20 10 150 10 20 40 APR 40 40 0 0
MAY 80 50 50 120 70 20 120 190 80 MAY 40 40 490 20 30 70 MAY 40 50 0 10
JUN 110 50 40 120 50 10 190 120 40 JUN 40 60 250 10 30 70 JUN 70 50 10 10
JUL 300 60 40 190 70 20 120 160 90 JUL 50 40 410 10 50 80 JUL 50 60 30 20
AUG 250 60 50 180 20 30 150 270 80 AUG 50 200 270 10 30 60 AUG 60 60 20 10
SEP 240 60 30 110 10 10 120 120 20 SEP 50 40 210 20 30 70 SEP 70 50 10 10
OCT 110 30 30 80 50 10 160 10 40 OCT 60 30 220 20 20 60 OCT 50 30 10 10
NOV 180 30 20 50 20 20 520 70 40 NOV 30 30 280 20 30 50 NOV 30 20 10 0
DEC 90 20 30 40 40 20 370 1180 40 DEC 30 10 190 10 20 20 DEC 20 20 10 0
mean 138 37 30 88 42 13 168 328 68 mean 34 41 252 13 24 51 mean 41 37 8 6
std dev 85 19 13 56 21 9 139 370 61 std dev 17 53 102 6 12 20 std dev 19 17 9 7
median 110 30 30 65 40 10 120 180 40 median 35 30 215 10 25 55 median 40 35 10 5
max 300 60 50 190 70 30 520 1180 250 max 60 200 490 20 50 80 max 70 60 30 20
min 40 10 10 30 10 0 60 10 20 min 10 10 150 0 10 20 min 20 20 0 0
41
Table 2.15 Chlorophyll a (mg/l) during 2012 at the Lower Cape Fear River Program stations.
NAV HB BRR M61 M54 M35 M23 M18 NC11 AC DP BBT IC NCF6
JAN 2 2 2 2 2 3 4 7 JAN 1 0 0 1 1 3
FEB 2 2 2 2 2 3 3 4 FEB 1 1 1 1 1 8
MAR 1 2 1 1 2 4 5 3 MAR 2 3 3 1 2 6
APR 1 1 1 1 3 4 5 7 APR 3 3 1 1 1 3
MAY 5 3 4 4 6 7 8 5 MAY 2 2 3 1 2 4
JUN 3 3 4 3 8 7 7 8 JUN 9 5 2 1 2 1
JUL 17 14 13 9 14 9 8 7 JUL 12 40 22 4 9 24
AUG 4 7 21 54 25 19 7 7 AUG 3 3 4 1 3 2
SEP 2 2 3 5 7 4 8 9 SEP 6 4 6 1 1 1
OCT 3 7 9 4 8 3 5 5 OCT 2 2 1 1 1 2
NOV 2 2 3 2 3 3 4 5 NOV 1 1 1 0 0 2
DEC 2 2 4 3 4 4 7 7 DEC 2 1 1 1 1 2
mean 4 4 6 8 7 6 6 6 mean 4 5 4 1 2 5
std dev 4 4 6 15 7 5 2 2 std dev 4 11 6 1 2 6
median 2 2 4 3 5 4 6 7 median 2 3 2 1 1 3
max 17 14 21 54 25 19 8 9 max 12 40 22 4 9 24
min 1 1 1 1 2 3 3 3 min 1 0 0 0 0 1
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2
JAN 2 2 2 3 2 32 2 2 1 JAN 1 1 1 2 1 1 JAN 3 1 1 1
FEB 3 1 2 2 3 30 2 2 1 FEB 2 1 1 4 1 1 FEB 2 0 1 0
MAR 2 3 2 1 4 3 2 3 1 MAR 1 1 1 1 1 1 MAR 1 1 1 2
APR 2 2 2 1 4 1 0 1 1 APR 1 1 1 1 1 1 APR 1 1 1 1
MAY 20 3 6 8 20 1 2 4 4 MAY 1 1 1 6 1 1 MAY 4 1 1 2
JUN 1 1 4 19 4 7 4 3 1 JUN 1 3 4 12 2 3 JUN 1 1 1 2
JUL 4 4 7 9 6 6 6 1 1 JUL 2 1 2 11 2 1 JUL 2 1 3 6
AUG 6 2 2 8 8 10 2 3 1 AUG 0 4 5 11 2 6 AUG 1 1 1 2
SEP 4 2 3 28 12 8 1 1 0 SEP 0 0 1 9 0 0 SEP 1 1 0 1
OCT 2 2 4 3 2 1 0 1 1 OCT 1 1 1 3 1 7 OCT 0 0 0 1
NOV 1 1 2 2 4 0 0 2 1 NOV 0 0 1 6 0 0 NOV 0 0 0 1
DEC 1 9 2 8 32 1 2 1 2 DEC 7 3 6 4 2 2 DEC 0 0 1 2
mean 4 3 3 8 8 8 2 2 1 mean 1 1 2 6 1 2 mean 1 1 1 2
std dev 5 2 2 8 9 11 2 1 1 std dev 2 1 2 4 1 2 std dev 1 0 1 1
median 2 2 2 6 4 5 2 2 1 median 1 1 1 5 1 1 median 1 1 1 2
max 20 9 7 28 32 32 6 4 4 max 7 4 6 12 2 7 max 4 1 3 6
min 1 1 2 1 2 0 0 1 0 min 0 0 1 1 0 0 min 0 0 0 0
42
012345678
NC
1
1
A
C
D
P
I
C
N
A
V
H
B
B
R
R
M
6
1
M
5
4
M
3
5
M
2
3
M
1
8
N
C
F
1
1
7
N
C
F
6
B
2
1
0
B
B
T
Chlorophyll a(g/L)
Fi
g
u
r
e
2
.
6
C
h
l
o
r
o
p
h
y
l
l
a
a
t
t
h
e
L
o
w
e
r
C
a
p
e
F
e
a
r
R
i
v
e
r
P
r
o
g
r
a
m
m
a
i
n
s
t
e
m
s
t
a
t
i
o
n
s
,
19
9
5
-
2
0
1
1
v
e
r
s
u
s
2
0
1
2
.
1995-2011 2012
43
Table 2.16 Biochemical Oxygen Demand (mg/l) during 2012 at the Lower Cape Fear River Program stations.
5-Day Biochemical Oxygen Demand
NC11 AC NCF117 B210 LVC2 BBT
JAN 0.3 0.4 0.8 0.8 0.8 0.7
FEB 0.4 0.8 0.7 3.7 0.8 0.5
MAR 1.6 1.6 1.1 1.0 0.8 1.7
APR 1.9 0.9 1.6 1.2 1.2 1.4
MAY 0.8 0.9 1.0 0.9 2.0 0.8
JUN 1.3 0.9 1.6 1.7 1.0
JUL 2.3 4.2 0.9 1.5 1.4
AUG 0.9 2.4 1.3
SEP 1.2 0.8 2.2 1.4 1.5 1.1
OCT 1.0 1.6 0.9 1.1 1.5 1.5
NOV 2.3 2.9 0.9 1.0 1.4 1.6
DEC 0.9 0.9 1.2
mean 1.3 1.6 1.1 1.4 1.3 1.2
stdev 0.7 1.2 0.5 0.8 0.4 0.4
median 1.2 0.9 0.9 1.1 1.3 1.2
max 2.3 4.2 2.2 3.7 2.0 1.7
min 0.3 0.4 0.7 0.8 0.8 0.5
20-Day Biochemical Oxygen Demand
NC11 AC NCF117 B210 LVC2 BBT
JAN 2.5 2.5 2.6 2.1 2.6 3.5
FEB 1.9 3.0 2.4 6.3 2.6 2.0
MAR 4.8 3.7 3.6 2.7 2.6 3.8
APR 4.4 2.7 4.3 3.2 3.2 4.0
MAY 2.7 3.8 3.3 2.6 6.0 2.7
JUN 3.5 3.2 4.9 4.3 3.4
JUL 5.2 9.3 2.8 3.1 4.4
AUG 3.0 6.3 3.8 3.3 2.9 3.6
SEP 2.6 1.8 5.2 3.1 3.6 3.3
OCT 3.1 4.0 4.0 3.4 4.9 3.8
NOV 4.6 6.3 2.9 2.4 3.4 4.2
DEC 3.6 2.1 4.5
mean 3.5 4.2 3.6 3.2 3.7 3.4
stdev 1.1 2.2 0.9 1.2 1.1 0.7
median 3.1 3.7 3.6 3.1 3.4 3.6
max 5.2 9.3 5.2 6.3 6.0 4.2
min 1.9 1.8 2.4 2.1 2.6 2.0
44
Table 2.17 Fecal Coliform (cfu/100 mL) and Enterococcus (MPN) during 2012 at the Lower Cape Fear River Program stations.
ENTEROCOCCUS
NC11 AC DP IC NCF6 NAV HB BRR M61 M54 M35 M23 M18
JAN 19 28 82 100 64 37 37 JAN 27 36 39 3 1 1
FEB 10 10 145 10 5 73 91 FEB 91 37 10 5 5 5
MAR 28 10 91 210 73 136 55 MAR 136 127 46 5 5 5
APR 10 5 5 37 19 82 154 APR 118 91 109 19 5 10
MAY 10 10 5 19 55 46 19 MAY 90 110 5 100 5 5
JUN 37 28 46 199 37 28 64 JUN 220 50 10 10 5 10
JUL 37 136 10 5 10 28 46 JUL 687 921 1,047 817 1,120 1,120
AUG 10 55 46 28 82 19 91 AUG 187 62 20 31 5 5
SEP 109 46 73 37 73 109 380 SEP 256 109 20 20 20 5
OCT 28 46 73 37 73 46 46 OCT 215 326 649 291 1,204 2,420
NOV 10 28 19 19 37 28 109 NOV 109 52 20 5 5 5
DEC 28 37 28 28 28 10 19 DEC 20 20 10 10 5 109
mean 28 37 52 61 46 54 93 mean 180 162 165 110 199 308
std dev 26 34 41 68 26 37 94 std dev 169 242 317 227 431 706
max 109 136 145 210 82 136 380 max 687 921 1,047 817 1,204 2,420
min 10 5 5 5 5 10 19 min 20 20 5 3 1 1
Geomean 21 25 33 35 36 42 65 Geomean 123 87 36 22 12 17
ANC SAR GS NC403 PB LRC ROC BC117 BCRR 6RC LCO GCO SR BRN HAM NCF117 B210 COL LVC2 SC-CH
JAN 46 91 28 5 10 118 181 109 46 JAN 91 19 19 28 37 910 JAN 46 5 37 19 200
FEB 1,182 82 19 19 46 37 163 200 580 FEB 100 2,273 490 19 118 13,000 FEB 19 10 37 5 46
MAR 55 230 37 64 190 109 190 109 28 MAR 82 28 28 19 200 154 MAR 19 46 37 19 55
APR 91 64 19 340 240 46 73 819 55 APR 73 73 73 109 100 154 APR 28 64 46 19 546
MAY 55 390 200 163 91 136 240 340 320 MAY 55 28 19 64 118 82 MAY 1,455 546 46 262 210
JUN 127 350 210 637 728 182 29,000 82 550 JUN 250 7,000 637 910 637 100 JUN 28 46 91 91 91
JUL 2,000 13,000 1,455 172 1,091 210 3,500 728 60,000 JUL 172 37 10 600 370 208 JUL 82 82 136 5,100 60,000
AUG 370 217 1,637 5,100 370 6,000 1,728 3,100 1,637 AUG 163 118 109 819 2,400 350 AUG 82 82 64 73 181
SEP 64 181 181 455 10 1,819 190 546 8,000 SEP 280 55 181 210 290 280 SEP 37 73 10 127 240
OCT 550 5600 260 546 540 100 728 380 190 OCT 82 73 290 230 728 380 OCT 55 28 100 390 510
NOV 37 82 118 64 181 1640 109 455 55 NOV 154 5 200 109 540 290 NOV 46 64 19 91 73
DEC 64 136 230 109 1090 546 118 380 230 DEC 280 163 280 82 290 1000 DEC 82 163 220 530 163
mean 491 1,803 451 904 346 1,056 4,384 680 7,913 mean 116 1,193 196 281 516 2,107 mean 240 114 44 873 10,171
std dev 675 4,234 638 1,726 354 1,952 9,372 1,016 18,571 std dev 63 2,313 237 371 791 4,455 std dev 497 178 10 1,891 22,285
max 2,000 13,000 1,637 5,100 1,091 6,000 29,000 3,100 60,000 max 250 7,000 637 910 2,400 13,000 max 1,455 546 64 5,100 60,000
min 46 64 19 5 10 37 73 82 28 min 55 5 19 19 37 82 min 19 5 37 5 46
Geomean 186 284 118 141 165 222 602 289 563 Geomean 103 100 82 91 206 361 Geomean 55 44 43 48 380
45