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Section 319
NONPOINT SOURCE PROGRAM SOCGESS STORY
Removing Agricultural and Residential Bacteria Sources Improves
Water Quality
WWqtprhnrlv Imnrnx/prl Excessive nutrient loading from agriculture operations and
' '"" "" "v* failing septic systems led to elevated bacteria levels in the
Gravelly Branch subwatershed. As a result, the Delaware Department of Natural Resources
and Environmental Control (DNREC) added a 6.5-mile-long segment of Gravelly Branch to
its 1996 Clean Water Act (CWA) section 303(d) list for bacteria. Project partners developed
nutrient management plans for local farmers, implemented agricultural best management
practices (BMPs), and connected failing septic systems to a central sewer system. These
activities significantly reduced bacteria levels in Gravelly Branch; as a result, Delaware
removed this segment from its 2008 CWA section 303(d) list for bacteria impairment.
Problem
Southern Delaware's Gravelly Branch subwatershed
drains into the Nanticoke River, which in turn flows
into the Chesapeake Bay (Figure 1). Gravelly Branch
begins in the town of Ellendale and flows south-
west toward the city of Seaford. The major land use
in the 24,423-acre Gravelly Branch subwatershed is
agriculture.
The town of Ellendale is situated on land with poor
soils and high seasonal groundwater levels. An
Ellendale-area survey conducted in 1989 showed
that 67 percent of homeowners with septic systems
had problems with their systems overflowing or
needing to be pumped out more than once a year.
Further, many Sussex County residents reported
concerns regarding potential health and public safe-
ty impacts from septic system effluent and drinking
water contamination. Today, most of the area cannot
be permitted for septic and other disposal systems
because of wastewater disposal regulations.
Delaware maintains a statewide General
Assessment Monitoring Network of 181 stations,
which provide data used to conduct long-term
status and trend assessments of water quality
conditions in the state's surface waters. Before
2006, Delaware collected data four to six times a
year. Since 2006, data have been collected six to
12 times a year for physical and chemical param-
eters, including bacteria. Gravelly Branch water
samples from the mid-1990s routinely exceeded
Delaware's water quality standard for enterococci
bacteria, which requires that bacteria levels not
Ellendale
Chesapeake Watershed
Gravelly Branch Watershed
Figure 1. The Gravelly Branch subwatershed lies within the
Chesapeake Bay Basin.
exceed a maximum geometric mean of 104 colony-
forming units (CFU) per 100 milliliters (ml) over a
five-year period. Consequently, a 6.5-mile-long seg-
ment of Gravelly Branch was placed on the state's
1996 CWA section 303(d) list of impaired waters
for bacteria. DNREC identified nonpoint sources,
including direct discharge from failing septic
systems and agricultural sources, as the probable
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sources of bacteria. Segments of Gravelly Branch
were also listed as impaired for dissolved oxygen
and nutrients (1996) and biology/habitat impairment
(1998).
Delaware completed a total maximum daily load
(TMDL) analysis for nutrients and dissolved oxygen
in the tributaries and ponds of the Nanticoke River
and Broad Creek watersheds in 2000. In 2006
Delaware developed a TMDL for bacteria for the
entire Chesapeake Bay drainage basin, including
the Gravelly Branch subwatershed. The TMDL
required that the nonpoint source bacteria load in
the entire Nanticoke River, Gum Branch, Gravelly
Branch, Deep Creek and Broad Creek watersheds
be reduced by nine percent from the 2000 to 2005
baseline level, and that all point source bacteria
loading in the entire Chesapeake Bay drainage
basin be capped at the current geometric mean,
100CFU/100mL
Project Highlights
The Sussex County Conservation District (SCO) pro-
vided technical assistance to the local farming com-
munity to help them develop nutrient management
plans; it also provided cost-share funding for imple-
menting agricultural BMPs. The SCO also partnered
with the U.S. Department of Agriculture's (USDA)
Natural Resources Conservation Service (NRCS),
to develop conservation plans and Environmental
Quality Incentive Program (EQIP) contracts. The
DNREC Nonpoint Source Program provided CWA
section 319 funding to support five SCO planners.
With the assistance of the planners, farmers in the
Gravelly Branch subwatershed installed 17 manure
storage sheds, 15 dead bird composters, one dairy
waste handling system, and 35 heavy-use-area
protection pads (concrete or other artificial surface
pads that help manage animal waste, sediment and
nutrient runoff).
USDA's Delaware Conservation Reserve
Enhancement Program (CREP), a voluntary land
retirement program that helps agricultural producers
protect environmentally sensitive land, was estab-
lished in Delaware in 1999 to improve water quality.
The DNREC Nonpoint Source Program directed CWA
section 319 funds to support a full-time Delaware
CREP Program Coordinator to assist in developing
and implementing the CREP program in the Gravelly
Branch subwatershed and other areas throughout
the state. In the Gravelly Branch subwatershed, the
CREP Program Coordinator worked with landown-
ers to enroll 204 acres of hardwood trees in the
land retirement program and supported 17 acres of
wildlife planting and 5 acres of wetland restoration
through the CREP program.
To address the failing septic systems throughout
Sussex County, the Ellendale-New Market Sanitary
District began operating in 2005 and connected
483 equivalent dwelling units (EDUs) to a central-
ized sewer system. Today, the town has 585 EDUs
connected to the system, and it has the remaining
capacity to permit another 250 new homes in the
district.
Results
After agricultural BMP implementation and removal
of failing septic systems, monitoring data collected
from Gravelly Branch between August 2004 and
September 2009 showed that 34 samples had a
geometric mean of 76.8 col/100 ml. This value was
well below Delaware's freshwater bacteria water
quality standard, which requires a geometric mean
below 104 col/100 mL for a period of five years. As
a result, DNREC removed Gravelly Branch from the
state's list of impaired waters in 2008. Monitoring
will continue in Gravelly Branch to ensure that it
continues to meet standards.
Partners and Funding
The success in the Gravelly Branch subwatershed
was the result of a partnership involving the SCO,
USDA, NRCS, and Delaware Nonpoint Source
Program. Approximately $705,000 in federal CWA
section 319 funds supported Gravelly Branch
subwatershed projects. Additional funding was pro-
vided through the USDA EQIP and CREP programs,
as well as the State of Delaware Conservation Cost
Share program. Approximately $1.7 million from
Delaware's State Revolving Fund and $3.8 million
from the state's 21st Century Fund supported the
development of the Ellendale-New Market sanitary
system.
I
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-12-001E
March 2012
For additional information contact:
Robert Palmer
Delaware Department of Natural Resources
and Environmental Control
Nonpoint Source Program
robert.palmer@state.de.us • 302-739-9922
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