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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