Water: Nonpoint Source Success Stories
Georgia (Section 319I - 1994)
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.