Internal Loading in Southeastern Piedmont Impoundments

Abstract

In Piedmont impoundments in Georgia, as well as lakes and impoundments throughout the world, accelerated eutrophication of lakes causes detrimental ecological effects such as algal blooms, lake anoxia and toxic metal release from sediments. It often renders water unsafe for agricultural use, recreation and drinking. To reduce the eutrophication of local Piedmont impoundments, recent regulatory controls for nutrients were established as part of the Clean Lakes program and courtordered total maximum daily loads. These regulatory efforts focus on the reduction and minimization of pointsource watershed nutrient inputs, primarily phosphorus, into lake systems, as phosphorus is the limiting nutrient in Piedmont impoundments. Reductions in phosphorus loading are expected to improve lake water quality. However, in the Piedmont, as well as worldwide, many lakes continue to experience algal blooms and lake anoxia after sources of external loading are discontinued. Internal loading has been identified to be a source of algal available phosphorus, as well as other nutrients. The conditions under which internal loading takes place are region-specific as they vary based on local physical, chemical and biological conditions. The purpose of our research is to quantify changes in algal biomass in response to internal loading from resuspended sediment in Lake Allatoona, Georgia. The results of a mesocosm experiment are used to evaluate potential appropriate remediation strategies to minimize detrimental algal blooms in Southeastern Piedmont impoundments.