3.8
Cape
Fear River Subbasin 03-06-21
Includes the Northeast Cape Fear River and Barlow Branch
Municipalities: Mount Olive
LCFRP Station Code (DWQ#): NC403
(94)
DWQ/UNCW ambient monitoring site(s): NC403
Waterbody: Northeast Cape Fear
River
Location: NC
Hwy 403, on the borders of Wayne and Duplin County
Lat/Lon: N
35.17838 W 77.98028 (NC403)
|
Use Support Ratings, from NCDENR, DWQ (Cape
Fear River Basinwide Water Quality Plan, July 2000):
Freshwater Streams
Fully Supporting:
69.3 mi.
Partially Supporting:
0.0 mi.
Not Supporting:
4.3 mi.
Not Rated:
6.8 mi.
Significant dischargers in this subbasin are Mount Olive Pickle Company and the
Town of Mount Olive. DWQ biological
assessment sampling resulted in no impaired rating for streams in this subbasin.
Portions of the Northeast Cape Fear River and Barlow Branch were identified as
impaired in the 1996 Basinwide Water Quality Plan.
The discharge from Mount Olive Pickle Company was the cause of
impairment. Chloride levels exceeded the water quality limit in 48% of the
samples from 1993 to July 1996, at Northeast Cape Fear River at SR 1937
approximately 2.7 miles from discharge source.
The ambient water quality station was relocated approximately 5.1 miles
downstream in 1996 to the NC403 site. The
ambient station data at NC 403 has not indicated high chloride levels.
Currently the Northeast Cape Fear River (3.3 miles from source to SR
1937) and Barlow Branch (1 mile) are not supporting (NS). (NCDENR,
DWQ, Cape Fear River Basinwide Water Quality Plan, July 2000)
The
Mount Olive Pickle Company discharges chlorides above permitted levels into
Barlow Branch before it joins the Northeast Cape Fear River.
The Mount Olive Pickle Company was given a variance from the state
surface water quality standard for chloride (230mg/L) in 1996.
They have met the requirements of the variance to date, and have reduced
water usage and salt usage. (NCDENR,
DWQ, Cape Fear River Basinwide Water Quality Plan, July 2000)
UNC-Wilmington
– Center for Marine Science, LCFRP
Station Name: NC403
Data collection: June 1997 –
present
Sampling relevance: Below Mount
Olive Pickle Plant
NC403 - slow
moving creek
The NC403 site was found to be poor quality
for dissolved oxygen concentrations, not meeting the NC State Standard of 5.0
mg/L in 67% of all samples. Even
when using the NC swampwater standard of 4.0 mg/L, NC403 was found to be poor
quality, not meeting the standard 58% of the time. For July - October 2002, and May - June 2003 the dissolved
oxygen levels were equal or less than 1.0 mg/L.
The mean for the 2002-2003 sampling period was 3.4 mg/L.
The dissolved oxygen concentrations are represented graphically in Figure
3.8.1.
For biological standards, NC403 was found to
be good quality in terms of chlorophyll a and fecal coliform bacteria
concentrations. Extensive aquatic
macrophyte vegetation characterizes this site.
NC403 was found to be good quality for
turbidity, with samples not exceeding the standard of 50 NTU during the
2002-2003 monitoring period.
UNCW researchers are concerned that elevated
nutrient levels are periodically found at this site. Nitrate-N concentrations >500 mg/L
occurred several times at NC403 during the 2002-2003 monitoring period, levels
that can cause algal blooms. High
total phosphorus (TP) concentrations occur at times (>500 mg/L),
which UNCW scientists find can stimulate increased biochemical oxygen demand (BOD)
and lead to lower dissolved oxygen levels (Mallin et al. 2002).
Nutrient concentrations are shown graphically for NC403 in Figure 3.8.2.
Figure 3.8.1 Dissolved
oxygen concentrations (mg/L) at NC403 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 3.8.2 Nutrient
concentrations (mg/L)
at NC403 for the 2002-2003
monitoring period.