Creative Strategies for Implementing Projects to Manage Nonpoint Source Pollution: A Case Study from the Mcdaniel Farm Park Stream Restoration Project

The Sweetwater Creek watershed is located in central Gwinnett County within the Ocmulgee River Basin. The study area is comprised of 26 square miles. A total of 153 projects were identified in the Watershed Improvement Plan (WIP) for Sweetwater Creek. Total cost of all projects was estimated at 15,044,500.Implementation of projects was broken down into two primary phases:Phase I – Prioritization of the recommended projects in the WIPPhase II – Project design and constructionProject prioritization included a review of data from the Sweetwater Creek WIP to develop a short list of BMP and stream projects for implementation. This was accomplished by conducting limited field work to review short listed projects. The work also included a review of regulatory requirements for potential projects and preliminary discussions of land acquisition issues.The McDaniel Farm Park stream restoration project was the first step in bridging the gap between watershed planning and implementation. As a result of the Phase I study, the McDaniel Farm Park stream restoration project was the first project chosen for implementation for a number of reasons. 1) The project was identified in the WIP as providing reduction in TSS because of eroding banks along an unnamed tributary to Sweetwater Creek. 2) The project was located on County-owned land within an existing park and the project could be completed on County-owned property, avoiding land acquisition that could cost the County additional time and money for the project. 3) Because the project is located in a park there will be a number of opportunities to provide public awareness and education to citizens regarding the program. 4) There was a nearby road construction project that was going to impact a stream channel and as a result the Georgia Department of Transportation (GA DOT) needed mitigation credits to obtain a 404 permit for the project. The McDaniel Farm Park stream restoration project could be used to provide mitigation for the road project. GA DOT cost for mitigation for the road project was 1.6 million.The McDaniel Farm Park stream restoration project involved the restoration of a deeply incised stream channel (South Tributary) and the restoration of stream buffers along the South Tributary as well as along Sweetwater Creek and another tributary within the Park (North Tributary).The stream design involved the use of natural channel design and soil bioengineering to stabilize the eroding banks. The final design plans were based on fluvial geomorphic techniques and measurements that included the following:Reference reach geomorphic features (e.g., dimension, plan, and profile)TopographyHydrologic conditionsRegional curve information from North Carolina and GeorgiaNatural vegetation communities in the areaThe restoration plan proposed for the McDaniel Farm Park tributary is summarized as follows:Approximately 1,260 feet of Rosgen Priority 1 and 2 stream restorationSpot repairs in about 165 feet of channelNorth and South Tributary and Sweetwater Creek riparian zone enhancement (e.g., exotic species control, replanting with native species) along 4,714 feet of channelErosion control at BMPsThe natural channel design included Rosgen Priority 1 and 2 restoration techniques in the incised channels. The design utilized channel geometry measurements of the existing channel and a reference reach, along with an evaluation of Piedmont regional curves to ensure the channel form is compatible with the site-specific hydrology. The existing channels were realigned and reconfigured to introduce a meander pattern, slope, and cross-section with a bankfull bench to dissipate flow energy of storm events. Elements of the proposed riparian zone and stream buffer project along the North and South Tributary and Sweetwater Creek included the following:Thinning existing overstocked riparian sapling stands adjacent to the North TributaryManaging exotic speciesPlanting with native plant species on floodplains and riparian areasAn extensive planting program was planned for the stream buffers. The planting areas were divided into 8 zones depending on the hydrology, slope, and on-site conditions. A total of 28.7 acres will be planted or treated with supplemental plantings to improve diversity. Approximately 1,300 pounds of native grass seeds, 3,200 live stakes, 1,260 shrub and trees seedlings, 11,754 containerize shrubs, and 1,880 balled and burlapped trees will be used to replant the site. Native hardwood, shrubs and herbaceous species that are endemic to the local area will be used.The project has been designed and was bid for construction in January 2006. Project construction is planned to start in July 2006. This restoration site provided mitigation for a large road project in Gwinnett County. The value of the mitigation was 1.6 million and was paid to Gwinnett County by GA DOT. It is likely that this project will be funded completely by the fee for the mitigation.