NONPOINT SOIREE SICCESS STOIY
Comprehensive Nonpoint Source Management Addressed Fecal
Coliform Bacteria Impairment in Bulls Bay, Shellfishing Area 7
atPrhnrlipQ Imnrnx/pH Malfunctionin9 sePtic systems, grazing livestock, pet waste,
VVd LUI UUUlUb ipl UVUU marjne vessels, illicit discharges and wildlife contributed
to high levels of fecal coliform (FC) bacteria in Shellfish Harvesting Area 7 of South Carolina's
Awendaw Creek and Bulls Bay watersheds. As a result, the South Carolina Department of Health
and Environmental Control (SCDHEC) added Shellfish Harvesting Area 7 to the 2002 Clean Water Act
(CWA) section 303(d) list of impaired waters for FC bacteria. To improve water quality and reopen the
shellfish beds, private citizens, the marine community, and local and state government collaborated
to implement agricultural best management practices (BMPs), shellfish bed restorations and septic
repairs. As a result, assessments for the 2014 CWA section 303(d) list showed that seven sites in the
previously impaired Shellfish Harvesting Area 7 now meet water quality standards for FC bacteria
and have been removed from the impaired waters list. The shellfish beds have been reopened and
now fully support their designated use for shellfish harvesting.
Problem
The focus area of the Sewee-to-Santee CWA section
319 project was the Atlantic Intercostal Waterway
and its adjacent marshland, from the northern
boundary of Shellfish Harvesting Area 7 extending
southwest to Station 07-02 at Graham Creek and a
contiguous portion of Doe Hall Creek seaward from
station 07-14 (Figure 1). The watershed draining to
the shellfish beds includes HUCs 030502090201 and
030502090202. The monitoring stations assessed for
this project each covers a 1-square-mile area (seg-
ment) within Shellfish Harvesting Area 7. The stations
include 07-02 (Graham Creek at Marker #64), 07-02A
(Graham Creek and Bulls Bay), 07-03 (Awendaw
Creek at Marker #57), 07-04 (Harbor River at Bulls
Bay), 07-05 (Tibwin Creek at Marker #42), 07-09
(Doehall Creek at Confluence of Aiww - North of
Marker #46) and 07-14 (Doehall Creek - Third Bend).
Data collected by SCDHEC at these stations indicated
a failure to attain the designated shellfish harvesting
use in Shellfish Harvesting Area 7, causing Shellfish
Harvesting Area 7 to be added to the 2002 CWA
section 303(d) list of impaired waters for FC bacteria.
These impairments were believed to be caused by
malfunctioning septic systems, grazing livestock, pet
waste, marine vessels, illicit discharges and wildlife.
The applicable state water quality standards for shell-
fish FC are defined as: not to exceed an MPN (most
probable number) fecal coliform 30-day geometric
mean of 14/100 milliliters (ml) with daily maximum
allowable values less than 43 MPN/100 ml.
Shellfish Harvesting Area 7
Harvest Classifications, Stations
and Potential Pollution Sources
Shellfish Harvest Classifications o shellfish Monitoring Sites
APP<0»ed > NPDES Permits
Conditionally Approved Marinas
Restricted
Prohibited
Downgraded: Approved to Restrkted Stormwater Permits
I I Shellfish Mgt. Harvesting Area
Figure 1. Shellfish Harvesting Area 7.
Project Highlights
The project included improved operation and func-
tion of on-site wastewater systems; outreach to the
marine community, local governments and water-
shed citizens; substrate renourishment of oyster
reefs; and the installation of agricultural BMPs.
On-site wastewater problems were a known issue
in the area, so initial efforts were focused there.
A Charleston Soil and Water Conservation District
(CSWCD) contractor conducted homeowner septic
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Figure 2. Local students conduct
a recreational boater survey at
McClellanville boat landing.
system workshops and
participant solicitation
in summer 2009 to
encourage improved
septic maintenance
and repairs. Over the
course of the project
there were 62 complete
septic system replace-
ments and four minor
repairs.
Potential marine sourc-
es of bacteria were
addressed by extensive
outreach, including
in-person surveys (2010
and 2012) at boat land-
ings. Local high school
students were recruited
to conduct these
surveys (Figure 2).
"Our Connected Coast"
signs were posted on
existing information
boards. With the assis-
tance of the U.S. Forest
Service, U.S. Fish and
Wildlife staff, and the
town of McClellanville,
four stand-alone sign
stations were constructed, including one at the
Sewee Visitor and Environmental Education Center.
In 2010 and 2012, The Nature Conservancy and
SCDNR planted more than 11,000 bushels of oyster
shells to enhance water quality and raise public
awareness (Figure 3). They also installed five pet
waste stations (completed in October 2012), at public
areas near waterways including a National Forest
Service campground, a trailhead and a boat landing.
Agricultural BMP implementation began in the
spring of 2012. With U.S. Department of Agriculture
Natural Resources Conservation Service (NRCS)
technical assistance, 10,300 feet of livestock fencing
was installed with a 20-foot buffer around drainage
ditches. This BMP included adding paddocks for
animal rotation and watering pipelines. Other outreach
activities undertaken by various partners included an
information booth at the Awendaw Blue Crab Festival,
other festivals, agricultural workshops, septic system
maintenance guides and TV information spots.
Figure 3. Partners pass mesh bags of
oyster shells as they help to create an
oyster reef on Tibwin Creek.
Coliform 90% Percentile (MPN/100 ml)
Decreasing Bacteria in Shellfish Beds
i
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i
i
1
— t-
§ 2003 2004 2005 2006
10% Exceedance Stand
T
-f-
Resto
Begin
i
2007 20
Years
ird(43MPN
ear (Averag
ation
J.
f-
Resto
Ends
*-.:
ation
*
8 2009 2010 2011 2012 2013
• Average 90% MPN
90%MPN)
Figure 4. Trend of decreasing FC bacteria impairment.
Average 90th percentiles in plot are calculated from
the 3-year average 90th percentiles for the seven
individual stations. Error bars represent one standard
deviation above and below the average 90 percent
MPN, providing some indication of how much bacteria
varied spatially throughout the shellfishing areas.
Results
Monitoring data collected at the completion of this
project showed FC bacteria was reduced at the
seven shellfish monitoring sites (Figure 4). On the
basis of these data, the seven shellfish monitoring
stations located within Shellfish Harvesting Area 7
have been delisted as of the 2014 CWA section
303(d) list. These shellfish beds now support their
designated use and have reopened for harvesting.
Partners and Funding
The restoration of shellfish beds in the Awendaw
Creek and Bulls Bay watersheds was the result
of collaboration between the U.S. Environmental
Protection Agency (EPA), CSWCD, SCDNR, The
Nature Conservancy, Charleston County, Charleston
County Community Services entitlement grant fund-
ing from the U.S. Department of Housing and Urban
Development program, and individual landowners and
septic contractors. The CSWCD received a $596,660
EPA CWA section 319 grant and matched it with
$84,731. The project was managed by CSWCD, its
contractor, and SCDNR. The SCDNR provided $40,000
in funding, along with technical and education sup-
port. The Nature Conservancy and Charleston County
supported the shellfish restorations and provided
$18,432 and $18,000 to this effort, respectively.
Lastly, individual landowners provided $18,974 in fund-
ing for septic system repairs and replacements.
yss
Ill
o
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001TT
October 2015
For additional information contact:
Scott Hagins, Nonpoint Source Coordinator
SCDHEC - Bureau of Water
Water Quality Division
803-898-1584 • haginsms@dhec.sc.gov
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