Section 319
NDNPDINT SDURCF PROGRAM SUCCESS STDRY
New Diversion Levee and Dike Protect Water Quality
Waterbody Improved
Sediment in runoff from pastureland and from non-irrigated crop
production caused siltation and a loss of habitat in Dry Creek. This led
Tennessee to place 17.8 miles of Dry Creek on its 303(d) list of impaired waters for siltation and habitat
alteration. To remedy this problem, local agencies installed a diversion levee that affected 83 acres and
a dike that affected another 5 acres in the watershed. These practices mitigated runoff from the crop
fields and prevented sediment from reaching the stream. As a result, water quality improved along the
17.8-mile Dry Creek segment, and Tennessee removed it from its 2006 303(d) list of impaired waters.
Problem
Dry Creek is in Benton County's Big Sandy River
watershed. Tennessee listed the creek as impaired
on its 2004 303(d) list because siltation and a loss
of habitat reduced the creek's biological integrity.
The creek did not meet the state standard for
the designated use of fish and aquatic life, which
requires that waterbodies have no distinctly visible
solids, scum, foam, oily slick, or the formation of
slimes, bottom deposits, or sludge banks of such
size or character that could be detrimental to fish
and aquatic life. Sediment from eroding stream-
banks and agricultural fields accumulated in Dry
Creek—physically altering the creek's substrate and
reducing viable habitat for macroinvertebrates and
fish.
Figure 1. Re-grading channel banks and installing a
levee along a rapidly eroding drainage area prevents
agricultural field runoff from entering Dry Creek.
Project Highlights
The Chickasaw-Shiloh Resource Conservation &
Development Program (RC&D) installed a diver-
sion levee in 1998 using Tennessee's Agricultural
Resources Conservation Fund (ARCF). The diversion
levee stopped runoff water from rapidly eroding the
upper end of a drainage channel (Figure 1). This site
had been contributing large volumes of sediment to
the creek. A diversion levee is a berm of earth that
redirects polluted runoff to a pipe or some other
controlled outlet that slows the water and allows
sediments and nutrients to settle out before the
water discharges to the stream. The RC&D con-
structed the diversion levee on an agricultural field
that was subsequently enrolled in the Conservation
Reserve Program, which promotes the retirement
of cropland along waterbodies. In this case, the
landowner, Mark Hargis, further protected the land
from erosion and eliminated sedimentation of the
stream channel by planting grass instead of crops
(Figure 2).
Figure 2. A completed levee system borders an
agricultural field, now converted to grassland.
Using matched Clean Water Act section 319
funds from the ARCF, the Benton County Soil
Conservation District constructed a dike in 2004 in
a different area of the watershed. The dike, also a
type of earthen berm, provides a barrier to protect
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people and cropland from flooding, while also
reducing erosion and preventing sediment from
further degrading aquatic habitat. Henry County Soil
Conservation agents advised landowners on the
technical design and specifications of best manage-
ment practices (BMPs), and provided oversight and
expertise during installation (see Figure 3 for BMP
location map).
Results
State monitoring data show that siltation and
habitat alteration declined, allowing the waterbody
to meet state standards. The quality of the in-
stream habitat improved, once again providing for
the development of a diverse aquatic community
that meets regionally based biological integrity
goals. Using U.S. Environmental Protection Agency
rapid bioassessment protocol III, state biologists
calculated a biological reconnaissance score
(biorecon) for Dry Creek, which is used to measure
compliance with the state water quality standard for
siltation. Biorecon—a tool used to assess stream
impairment—uses species richness measures,
emphasizing the presence or absence of indicator
organisms without regard to relative abundance.
The biorecon index is scored on a scale from 1 to
15. A score of less than 5 is regarded as very poor.
A score of more than 10 is considered good. The
principal metrics used are the total macroinverte-
brate families, the number of families of mayflies,
stoneflies, and caddisflies (collectively referred to
as EPT—short for the order names Ephemeroptera,
Plecoptera, and Trichoptera), and the number of
pollution-intolerant families found in a stream.
In 2004 biological sampling of Dry Creek, state
biologists documented 23 total macroinvertebrate
families, including 4 EPT families and 1 intolerant
family. The biological reconnaissance (biorecon)
score for the station was 11 out of a total score of
15, which is in the unimpaired range. Therefore,
Tennessee removed Dry Creek from its 303(d) list
in 2006.
Partners and Funding
This project was funded through cost-sharing
from section 319 grant pool projects. The ARCF
provided $2,500 in state matching funds, and
landowner Mark Hargis donated $3,343. Additional
key partners in this effort included the Henry and
Benton counties' Soil Conservation Districts and the
Chickasaw-Shiloh RC&D.
Diy Creek in Benton County
Big Sandy River Watershed. TN0604000S0702
Hgnrv County
per TDEC 2004 303(d) List
1 Fully Supporting
Not Supporting
I Not Assessed
I Dry. Insufficient Information
• BMPS blltallfd 1999-2005
Citin In Bmrtnn County
I I BigSindyWMBrihid
Benton County
September 2006
Figure 3. Map indicating
the locations of the two key
BMP measures (diversion
levee and dike) installed in
the Dry Creek watershed
(see the lower-right portion
of the map).
PR
U.S. Environmental Protection Agency
fc Office of Water
g Washington, DC
r
EPA841-F-08-001I
July 2008
For additional information contact:
Sam Marshall
Tennessee Department of Agriculture
615-837-5306
Sa m. Marsha II @state.tn. us
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