Forecast-Informed Prerelease Reservoir Operations for Flood Risk Management

Reservoirs serve multiple purposes, and their operations must be performed effectively to reduce flood risk and safeguard infrastructure integrity as well as to address other purposes. Operators may be able to use forecasts to enhance flood risk management (FRM) and improve outcomes for other objectives. Such operations have been termed by the American Meteorological Society as “forecast-informed reservoir operations” (FIRO). This review focuses on reservoirs for which FRM is a primary or key objective and at which FIRO can include preemptively evacuating reservoir storage ahead of a significant inflow event (i.e., prerelease). While prerelease operations have been discussed for some time for hydrologic or inflow forecasting, implementing weather forecasts in FRM reservoir operations is a more recent development. This review summarizes and assigns consistent terminology for methods described in the literature and discusses analysis techniques to assess prerelease viability, the identification of factors that drive prerelease effectiveness, and the advances that have enabled forecast-informed prerelease to be implemented. Findings from this paper and recent sources are used to summarize the likely directions for future research concerning forecast-informed prerelease operations.