Water quality dynamics in the discharge of a southeastern hydropower reservoir: Response to peaking generation operation

Abstract

Sampling was conducted to determine the distribution and fate of physicochemical constituents in the releases from West Point Dam, a hydropower project located in west-central Georgia. Routine operation of the dam resulted in two distinct release regimes; peaking operation with meta- or hypolimnetic withdrawal and low-flow operation with near-surface withdrawal. Differences in release water quality were associated with stratified conditions in the reservoir forebay and changes in release regime. Temperatures were most responsive to diel conditions and dissolved oxygen concentrations varied with release type. Concentrations of total iron and manganese in die tailwater, which ranged from 0.3 to 1.9 and 0.1 to 0.5 mg/L−1, respectively, were influenced by hydrograph dynamics, downstream tributary inflows, and physicochemical processes. Longitudinal gradients were observed as increases in dissolved oxygen concentrations and decreases in metals concentrations during steady-state conditions. Processes leading to losses of iron and manganese included oxidation, adsorption, and sedimentation. © 1995 Taylor & Francis Group, LLC.