3.10
Cape
Fear River Subbasin 03-06-23
Includes the Northeast Cape Fear River and Burgaw Creek
Municipalities: Town of Burgaw
LCFRP Station Codes (DWQ #): ANC
(69), BCRR (82), BC117 (83),
NCF117 (84), NCF6 (85)
DWQ ambient monitoring site(s): NCF117
Waterbody: Northeast Cape Fear and
tributaries
Location: Pender
and New Hanover Counties
Lat/Lon: N
34.65705 W 77.73485
(ANC)
N 34.31710
W 77.95383 (NCF6)
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Use Support Ratings, from
NCDENR, DWQ (Cape
Fear River Basinwide Water Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
304.1 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
14.3 mi.
Not Rated:
37.5 mi.
This
subbasin is located in the outer coastal plain and contains the Town of Burgaw.
Most streams in this area are slow flowing blackwater streams, and many
dry up or stop flowing during the summer. Much
of the subbasin is undeveloped and included in either the Holly Shelter Game
Refuge or the Angola Bay Game Refuge. (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan,
July 2000)
There
are six permitted dischargers in the subbasin, with the largest dischargers
being Occidental Chemical, Thorn Apple Valley, and Burgaw WWTP.
Ambient chemistry data show average nutrient levels in the Northeast Cape
Fear River at US 117 to be lower than more upstream river sites. Biological rating resulted in impaired ratings for four of
the seven stream segments. Benthic
macroinvertebrate data showed fairly stable water quality for most of the
subbasin, exceptions include Burgaw Creek below WWTP, and Burnt Mill Creek in
Wilmington, both of which were rated poor.
(NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
Portions of Burnt Mill Creek and Burgaw Creek are currently rated as impaired
according to recent DWQ monitoring. Burnt
Mill Creek (4.8 miles from source to Smith Creek) was not supporting (NS) in the
1996 plan and is currently not supporting (NS) because of impaired biological
community. Instream habitat
degradation associated with urban nonpoint sources and channel dredging is a
possible cause of impairment. This
stream is on the state’s year 2000 303(d) list.
(NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)
Burgaw
Creek (9.5 miles from Osgood Canal to the Northeast Cape Fear River) was not
supporting (NS) in the 1996 plan, and is currently non supporting (NS) due to
impaired biological community. Instream
habitat degradation associated with urban nonpoint sources is a possible cause
of impairment. There are
indications of excessive nutrients in this stream, and fecal coliform bacteria
are also noted as a problem parameter. Failing
septic systems have been noted in this watershed as well.
The stream is channelized and has been adversely impacted by desnagging
activities after Hurricane Fran. This
stream is on the state’s year 2000 303(d) list. (NCDENR, DWQ
Cape Fear River Basinwide Water Quality Plan, July 2000)
UNC-Wilmington
– Center for Marine Science, LCFRP
Station Names: ANC, BCRR, BC117,
NCF117, NCF6
Data collection: NCF117 & NCF6
since June 1995, all others since
February 1996
Sampling relevance: point and
nonpoint source dischargers
ANC -
Angola Creek, swamp reference
site, tributary of the
Northeast Cape Fear
BC117 -
Burgaw Canal at US 117,
downstream of Burgaw WWTP
NCF117
- Northeast
Cape Fear River at
US117, also a DWQ ambient
monitoring site
Almost all sites within
this subbasin were rated as poor quality in terms of dissolved oxygen
concentrations. BC117 was the
exception, rated as fair quality, and not meeting the 5.0 mg/L standard in 17%
of sampled months. NCF117 and NCF6
were both found to be poor quality, not meeting the standard in 33% of samples.
BCRR was found to be poor quality, not meeting the standard 42% of the
time. ANC was also found to be poor
quality, not meeting the standard 58% of the time.
In five of the twelve sampled months, dissolved oxygen concentrations
were less than 1.0 mg/L at ANC. All
sites were also rated using the NC swampwater standard of 4.0 mg/L.
BC117, NCF117 and NCF6 were rated good quality for dissolved oxygen
concentrations, and ANC and BCRR would still be poor quality, not meeting the
4.0 mg/L standard in 42% of sampled months.
The dissolved oxygen concentrations are shown graphically for the four
sites found to be poor quality in Figure 3.10.1.
All sites in this subbasin
were found to be good quality in terms of chlorophyll a concentrations.
Mean for the 2002-2003 monitoring period were all less than 10 mg/L,
well below the NC State Standard of 40 mg/L.
Two sites, NCF117 and NCF6
were found to be good quality for fecal coliform bacteria concentrations.
Two sites, ANC and BCRR were found to be fair quality, exceeding the
human contact water (200 CFU/100mL) standard 25% of the time.
One site, BC117 was found to be poor quality, exceeding the standard 42%
of the time. The geomean for BC117
for the 2002-2003 monitoring period was 195 CFU/100mL, with the highest
concentrations of 1430 CFU/100mL found in December 2002.
Fecal coliform bacteria concentrations for ANC, BCRR and BC117 are shown
graphically in Figure 3.10.2.
All sites within this
subbasin were found to be good quality for turbidity. The mean value for all stations and all months for this
subbasin for the 2002-2003 monitoring period was 11 NTU.
Nutrient loading,
especially of nitrate-N and total phosphorus (TP) was a severe problem at BC117
(Figures 3.10.3 and Figure 3.10.4). Both
nitrate-N and TP were the highest levels seen in the LCFRP system.
These levels were far above the concentrations known to lead to algal
bloom formation, bacterial increases and increased biochemical oxygen demand (BOD)
in blackwater streams (Mallin et al. 2001, Mallin et al. 2002).
BCRR and ANC also periodically experienced elevated nutrient levels as
well.
UNCW also samples Burnt
Mill Creek as part of the Wilmington Watersheds Program. Our data show excessive fecal coliform bacteria
concentrations, low dissolved oxygen levels, and high sediment metal
concentrations. These data are
available in hardcopy from Dr. Michael Mallin and also online in report format
at this website:
http://www.uncw.edu/cmsr/aquaticecology/TidalCreeks/Index.htm
Figure 3.10.1 Dissolved
oxygen concentrations (mg/L) for the 2002-2003 monitoring
period.
The line shows the NC State Standard of 5.0 mg/L and the dashed line
shows
the swampwater standard of 4.0 mg/L.
Figure 3.10.2 Fecal
coliform bacteria concentrations (CFU/100mL) for the
2002-2003 monitoring
period. The line shows the NC State
Standard for human
contact waters of 200 CFU/100mL.
Figure 3.10.3 Nitrate-nitrite
concentrations (mg/L)
for BC117 for the 2002-2003 monitoring period.
Figure 3.10.4 Total
phosphorus concentrations (mg/L)
for BC117 for the 2002-2003 monitoring period.