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GEORGIA
Atlanta metropolitan area streams have suffered from substantial sediments
caused by eroding and undercut streambanks. To reduce this sediment pollution,
an amendment to Georgia's Erosion and Sedimentation Act requires that
construction activities maintain a 25-foot natural buffer along state
waterways. With section 319 funds, Georgia has helped reestablish natural
buffers by supporting demonstration streambank restoration projects and
preparing a streambank stabilization manual based on soil bioengineering
principles. Applying these principles, however, requires educating local
organizations responsible for drainage and streambank maintenance.
Revegetation Reigns in Streambank Venture
DeKalb County's Vegetative Streambank Program grew directly from the
county's desire to improve water quality by reducing nonpoint source pollution.
The county chose the South Fork Peachtree Creek in Medlock Park as its first
demonstration project. Here, lost streambank vegetation and increased water
velocity and volume had widened the channel and severely undercut its banks.
Funded in part by an FY 1993 section 319 grant of $34,000 and an FY 1994 grant
of $24,000, the Vegetative Streambank Stabilization and Reclamation Program was
a joint effort of DeKalb County's Department of Parks and Recreation and
Department of Roads and Drainage. This program complements an existing program
that provides riprap to citizens to use in stabilizing streambanks. The
following activities contributed to the project's success:
- Restoration plans were reviewed with the County - Development Department
and Corps of Engineers to obtain a construction permit.
- Letters were sent to park user groups and signs were posted to inform
general users of the restoration activities.
- Small trees were temporarily relocated and sewer and other utility lines
were marked.
- Because erosion and sediment control practices restricted soil disturbance
to above the existing water line, disturbed areas were seeded and covered with
erosion control fabric immediately after grading and especially before rain was
due.
- Banks were excavated and graded, creating a 3 to 1 slope; excess soil was
stored off site.
- Banks were hand raked and seeded heavily with a mix of fescue and rye
grass. Biodegradable erosion control fabric was placed over the seeds and held
in place by Type 3 riprap at the toe of the slope
- Boy Scouts gathered black willow cuttings from another park and planted
them through the erosion control fabric.
- After construction, disturbed areas were pulverized, fine graded, and
seeded. Straw was placed on a 30- to 40-foot swath along the streambank.
- A construction fence was installed to allow the grass to grow
undisturbed.
The project was completed in April 1993. The revegetation has been a great
success. Not only has it halted streambank erosion, but it has also provided a
contiguous wildlife corridor, increased environmental awareness, and
demonstrates best management practices for stormwater management.
The black willow cuttings are thriving--some have grown into 4-foot shrubs.
Other native grasses, trees, and self-seeded wildflowers are also thriving. The
newly vegetated streambank has endured numerous heavy rainfalls without any
substantial erosion. The success of the streambank program has prompted the
county to fund a permanent project manager to oversee continued revegetation
and stabilization projects.
Other demonstration projects are in progress or scheduled, including an
information pamphlet about vegetative stabilization methods. The program also
assists homeowners through consultations, plant materials, and volunteer
coordination. The second year proposal includes a continued demonstration site,
along with a "how to" video and workshops.
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