3.6  Cape Fear River Subbasin 03-06-19
Includes the Black River, Six Runs Creek and Great Coharie Creek
Municipalities: Town of Clinton

 
LCFRP Station Codes (DWQ #):  LCO (64), GCO (63), 6RC(65)
DWQ/UNCW ambient monitoring site(s): none
Waterbody:  Little Coharie Creek, Great Coharie Creek and Six Runs Creek, all flow to the Black River
Location:  Sampson County
Lat/Lon:  N   34.91857   W   78.38873   (GCO)
                N   34.79357   W   78.31192   (6RC)

Use Support Ratings, from NCDENR, DWQ (Cape Fear River Basinwide Water Quality Plan, July 2000): 
Freshwater Streams
Fully Supporting:                   452.1 mi.
Partially Supporting:             15.0 mi.
Not Supporting:                     0.0 mi.
Not Rated:                              40.2 mi.

        This subbasin is located in the coastal plain within Sampson County.  Land adjacent to the Black River is primarily undisturbed forest.  There is a very high concentration of hog farms within these watersheds.  There are 7 permitted dischargers, the largest of which is the Town of Clinton.  (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)

        Stewarts Creek (15.0 miles from source to Six Runs Creek) is currently partially supporting (PS) due to an impaired biological community.  The Town of Magnolia discharges into a tributary, which eventually flows to Stewarts Creek downstream of Warsaw.  The Magnolia WWTP has had problems with effluent toxicity and has been fined monthly since November 1999.  Stewarts Creek is the only stream in the subbasin that is impaired and on the state’s year 2000 303(d) list. (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000)

        Portions of Great Coharie Creek, Little Coharie Creek, Six Runs Creek and Crane Creek were impacted during Hurricane Fran in 1996.  These steams were also subject to massive desnagging operations after the storm.  Benthic monitoring is recommended to determine the impacts of de-snagging operations that remove important habitat in these waters (NCDENR, DWQ Cape Fear River Basinwide Water Quality Plan, July 2000).

UNC-Wilmington – Center for Marine Science, LCFRP
Station Names:  LCO, GCO, 6RC
Data collection:  February 1996 to present
Sampling relevance:  Concentrated animal operations (CAOs) within 
the watershed, reference areas for point and nonpoint source pollution

 
               GCO - blackwater stream, drains
                   riparian wetlands in an area with  
                   concentrated animal operations

        Of the three sites within this subbasin, 6RC and LCO were found to be fully supporting (FS) by UNCW for dissolved oxygen.  GCO was found to be partially supporting (PS) for dissolved oxygen, when rated by the North Carolina State Standard for swampwater of 4.0 mg/L.  This site had dissolved oxygen concentrations below 4.0 mg/L in 17% of all sampled months.  GCO had dissolved oxygen concentrations below 5.0 mg/L in four of the twelve months sampled in the 2001-2002 monitoring period (33%).  If this station was rated using the regular NC State Standard for dissolved oxygen of 5.0 mg/L, it would be non supporting (NS).  This creek does drain swamp areas, so it will normally have lower dissolved oxygen concentrations and be considered under the swampwater standard.

        All stations within this subbasin were found to be fully supporting (FS) for chlorophyll a concentrations.  The mean for all stations and all months was 1.7 mg/L.  The North Carolina State Standard for chlorophyll a is 40 mg/L.

        Two of the three sites within this subbasin were found to be fully supporting (FS) for fecal coliform concentrations.  LCO did not have any fecal coliform concentrations that exceeded the North Carolina State Standard for human contact of 200 CFU/100 mL.  GCO only had one month that exceeded the standard with levels of 234 CFU/100 mL.  6RC was found to be partially supporting (PS), exceeding the standard 17% of the time.

        All sites within this subbasin were found to be fully supporting (FS) for turbidity.  No samples within this monitoring period exceeded 30 NTU, with averages of below 7 NTU.  The North Carolina State Standard for turbidity is 50 NTU.