Trade-Offs between Phosphorous Discharge and Hydropower Production Using Reservoir Regulation

Abstract

The management of water flow using reservoirs for the purpose of hydropower production can have significant impacts on solute transport. Reducing the phosphorous load to downstream areas can be of great importance for aquatic habitats associated with recipient waters, as well as for the overall health of coastal and estuary areas. This study demonstrates a combined operation of a network of reservoirs with the objectives of hydropower production and improvement of water quality in downstream areas using a multiobjective approach and incorporating the transport of phosphorous in the watershed. A genetic optimization method was used to determine the trade-off between power production and mitigation of phosphorous discharge in the reservoir network of the Dalälven River, Sweden. The phosphorous export can be reduced (−5%) with a limited loss of power production (−4.3%), but further reduction is associated with a significant loss in total power production. The trade-off between the two objectives is determined using Pareto diagrams and examined for varying particulate conditions.