Georgia localities complete watershed study

The governments of Forsyth County, Hall County and Gainesville, Ga., have recently completed a watershed assessment in preparation for the development of strategies to enhance and protect the region’s water sources. Acting on a statewide directive from the Georgia Department of Natural Resources Environmental Protection Division (EPD), Atlanta, the communities undertook the project a year ago and are using their findings as the basis for new and revised ordinances, land-use guidelines and public education campaigns.

The Community Watershed Assessment Project consisted of four components: * Characterization. The governments tested the water chemistry at 35 stream sampling locations. Sampling was performed once a week over two seasonal four-week periods (in June 1999 and again in September), and data from those sites were compared to data collected during the same period from five reference stations. (The reference stations represented relatively unaffected watersheds in the same basins and ecoregions as the sampling sites.)

The samples indicated that some watersheds are in good shape, while others show signs of degradation. Generally, streams in urbanized areas of the communities were affected by altered hydrology; erosion and sedimentation; degraded habitat; and elevated levels of fecal coliform bacteria. In agricultural areas, sedimentation was the dominant problem, followed by fecal coliform and habitat degradation. However, nutrient loadings were below levels often measured in agricultural areas.

In addition to monitoring and sampling the water quality, the governments documented the number and variety of aquatic life forms and assessed the status of the habitats. All of the characterization data was used to establish a baseline for future water quality comparisons.

* Modeling. Using PLOAD, a spreadsheet-based program from Denver-based CH2M Hill (the project’s primary consultant), the governments were able to simulate changes in the region’s watershed. The characterization data were used as the baseline, and future conditions were simulated by inputting projected rainfall; types and densities of development; and other land uses. For each scenario, the program then predicted the amount of pollutionor stormwater that might enter a stream.* Management planning. Once the govern ments had identified the factors that might affect water quality, they began the process of identifying appropriate measures for protecting the watershed. They appointed a technical advisory group, consisting of agricultural business representatives, environmentalists, builders, homeowners, soil conservationists, the state DOT and universities, to ensure that resulting management plans would be comprehensive.

The planning phase of the project, which involved identification of Best Management Practices, took roughly six months to complete. Recognizing that, when it comes to BMPs, one size does not necessarily fit all, the governments identified a variety of options that each could employ as needed. They included:

— improving riparian buffers;

— establishing 100-foot buffers around perennial streams. The first 50 feet of a buffer would be undisturbed, while the remaining portion of the buffer would be a managed zone (e.g., an alternate-use area, such as a trail, but with no impervious surfaces);

— establishing regional detention ponds;

— improving erosion and sedimentation controls;

— using infiltration trenches; and — using semi-impervious surfaces in parking lots to aid in stormwater filtration and groundwater absorption.

* Public education and involvement. Throughout the study, the governments scheduled public meetings and briefings for elected officials. They held public meetings in each of 12 sub-watersheds to explain the purpose of the project, and they returned this past February and March to report their findings.

With the completion of the Community Watershed Assessment Project, Forsyth County, Hall County and Gainesville are positioned to make some changes to their watershed protection programs. The project consultant has presented recommendations to each of the participating governments, and local officials are in the process of reviewing those.

By next year, they expect to adopt new and revised watershed protection ordinances. That will mark the beginning of three-year phase, in which the changes are implemented, monitored and updated as necessary.

For more information about the Community Watershed Assessment Project, contact Tim Perkins, director of the Forsyth County Department of Water and Sewer, (770) 781-2160; Rob Rivers, utilities and special programs manager for Hall County, (770) 531-6800; or Tim Merritt, manager for the Water Quality and Treatment Division of Gainesville’s Public Utilities Department, (770) 538-2412.