A review of stormwater best management practices for karst areas

Stormwater runoff can pollute receiving waters and cause local flooding. Such runoff commonly contains heavy metals, animal and human wastes, grease, oil, sediment, and other potential pollutants. In karst areas, these impacts to groundwater can be magnified because of the nearly direct input of these contaminants to groundwater when runoff flows into sinkholes or through sinking streams. In addition, sinkholes can flood, creating a nuisance and/or damage to surrounding areas. Stormwater management practices that are applicable to controlling water quantity and quality are not necessarily effective in karst at eas. Because karst drainage is not always recognized or understood, prevention of flooding and pollution in such areas through application of best management practices (BMPs) and regulatory controls has not been fully realized. Stormwater BMPs which may work well for controlling water quantity in karst areas are dry detention ponds, runoff spreaders, porous pavement, and increased vegetation density. For controlling water quality, the use of skimmers, wet retention ponds, wetlands, and filtration systems may be applicable. These BMPs would be effective if installed near the sinkhole area or throughout the watershed. The discussion of two case studies in Knoxville, Tennessee, shows that some advances have been made in applying stormwater BMPs in karst areas and classifying sinkholes as Class V Injection Wells.