Recommended Flows to Protect Aquatic Habitat in Georgia Streams

Abstract

Rising demand for surface water withdrawals to support a rapidly growing population prompted us to compare Georgia's current method of protecting stream flows below permitted withdrawals with other methods considered adequate by fisheries professionals for protecting aquatic habitat. U.S. Geological Survey stream gage records from 31 widely-distributed sites were analyzed for broadly applicable relationships among parameters such as average annual flow, mean monthly flow, and 7Q10 flow, in order to define a flow policy that would preserve good habitat quality for most aquatic organisms. These analyses, coupled with a thorough literature review, were used to develop higher flow recommendations that were submitted to the State Environmental Protection Division for replacing the current policy that reserves only the 7Q10 flow (the lowest average flow expected for seven consecutive days with an average frequency of once in ten years).