Predicting Quality Effects of Pumped Storage

Pumped storage operation (PSO) affects the water quality and in turn the resident biota. A predictive technique was adapted from a recently developed ecologic model to calculate the environmental changes and to evaluate the alternatives of PSO that might enhance a normal ecological succession, forestalling adverse environmental problems. The model, in an application to Smith Mountain Reservoir, Virginia, predicted accurately for an entire year the distributions of daily temperature, dissolved oxygen and other quality constituents that were measured and reported in the literature. PSO, under simulated conditions, was found to improve water quality by deepening the epilimnion. A prolonged pumping schedule at a reduced rate, however, was a better alternative because it would provide a more stable ecosystem without substantially altering the thermal stratification. Thermal stratification is necessary to regulate energy loss, and thus control evaporation and to ensure a varied environment suitable for hosting a diverse and stable biota.