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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)

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

Two sites within this subbasin were found by UNCW to be fully supporting (FS) for dissolved oxygen concentrations when compared with the North Carolina State Standard for swampwater of 4.0 mg/L. Burgaw Canal at US 117 (BC117) had only one month below standard, December 2001, when dissolved oxygen (DO) concentrations were 3.9 mg/L. The other fully supporting (FS) site was NCF6, located at the Northeast Cape Fear River six miles upstream of Wilmington. Dissolved oxygen did not fall below the North Carolina Swampwater Standard of 4.0 mg/L. NCF117, the Northeast Cape Fear River at US117, was partially supporting (PS), with DO levels below 4.0 mg/L in two of the months (17% of time). Two sites, Angola Creek (ANC) and Burgaw Canal above WWTP (BCRR) were non supporting (NS) for dissolved oxygen. BCRR only met the standard in 50% of samples, with DO concentrations below 1.0 mg/L in October, November and December 2001. The mean for the 2001-2002 monitoring period was 3.5 mg/L. ANC also had problems with low DO, not meeting the standard 58% of the time. Seven of the twelve months sampled at ANC had dissolved oxygen concentrations of less than 3.0 mg/L (Figure 3.10.1).

Most sites within this subbasin were found to be fully supporting (FS) for chlorophyll a concentrations. BCRR was found to be partially supporting (PS), exceeding the North Carolina State Standard of 40 mg/L 25% of the time. The highest level of 84.3 mg/L was found in June 2002 (Figure 3.10.2).

The two sites on the Northeast Cape Fear River, NCF6 and NCF117, were found to be fully supporting (FS) for fecal coliform bacteria concentrations. Angola Creek (ANC) was partially supporting (PS) with two months which had samples above 200 CFU/100mL (17% of the time). The two sites on Burgaw Canal were both rated as non supporting (NS). BCRR had elevated fecal coliform levels 50 % of the time, with highest levels found in winter months. BC117 was also non supporting (NS), exceeding the standard 67% of the time (Figure 3.10.3).

All sites within this subbasin were fully supporting for turbidity. The North Carolina State Standard for turbidity, 50 NTU, was not exceeded during this monitoring period. The mean for all stations for the 2001-2002 monitoring period was 12.6 NTU.

Nutrient loading, especially of nitrate-N and total phosphorus (TP) was a severe problem at BC117 (Figures 3.10.4 and 3.10.5). Nitrate-N concentrations were the highest seen in the LCFRP system. The nitrate+nitrite and TP concentrations were well above levels known to lead to algal bloom formation, bacterial increases and increased biochemical oxygen demand (BOD) in blackwater streams (Mallin et al. 2001; Mallin et al. 2002). ANC 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 counts, low dissolved oxygen levels, and high sediment metals concentrations. These data are available in hardcopy from Dr. Mallin and also online in report format at this website:
http://www.uncwil.edu/cmsr/aquaticecology/TidalCreeks/Index.htm

Figure 3.10.1 Dissolved oxygen (mg/L) for ANC, BCRR, and NCF117. The line
shows the NC State Standard for dissolved oxygen of 5.0 mg/L and the dashed
line shows the NC State Standard for Swampwater of 4.0 mg/L.

Figure 3.10.2 Chlorophyll a concentrations (mg/L) for ANC, BCRR, and BC117.
The line shows the NC State Standard for chlorophyll a of 40 mg/L.

Figure 3.10.3 Fecal coliform bacteria concentrations (CFU/100 mL) for ANC, BCRR,
and BC117. The line shows the NC State Standard for fecal coliform bacteria for human
contact of 200 CFU/100 mL.

Figure 3.10.4 Nitrate + Nitrite concentrations (mg/L) for ANC and BC117.

Figure 3.10.5 Total phosphorus concentrations (mg/L) for BC117.