Reliability programing in reservoir management: 2. Risk‐loss functions

The reliability programing approach for reservoir management is based on the concept of risk-loss functions. This paper presents a methodology for deriving the risk-loss functions associated with the violations of a freeboard constraint (flood risk) and a water supply storage constraint (drought risk). A relation between the amount of water excess or shortage and its corresponding reliability level is first established. The excesses or shortages are then related to damages (losses). This provides the basis for a final relation of the reliability levels and the damages. A similar approach can be followed in developing the risk-loss functions associated with other reservoir purposes, such as recreation, navigation, and water quality enhancement. The hydrologie, hydraulic, and economic data necessary for developing the riskloss functions are discussed. The methodology is illustrated using data from the Blue Marsh Reservoir on Tulpehochen Creek, Schuylkill River basin, Pennsylvania.