Basinwide Considerations for Water Quality Management: Importance of Phosphorus Retention by Reservoirs

Reservoirs are designed and operated to control the flow of rivers to achieve flood control, water storage, power generation, irrigation, navigation, and other beneficial uses. From a water control or water quantity standpoint, reservoirs within the same drainage basin are often viewed as an integrated system to be optimized to achieve authorized reservoir uses and basinwide water control objectives. While methods for accomplishing this are well established, similar basinwide considerations for water quality are less common. This technical note provides a theoretical basis for implementing basinwide water quality management by considering the water quality influences of reservoirs on regulated rivers, specifically, the retention of phosphorus.