Forecast-Informed Flood Management: Reservoir Operations at Folsom Lake, California (Invited Presentation)

Codified forecast informed flood management for reservoir operation is a significant paradigm shift from the prior century’s mindset. Past flood management regulatory rules offered little confidence in meteorological forecasts where static inflow based constructs were the norm. Regulatory and project agencies responsible for Folsom Lake, near Sacramento California, have demonstrated forecasting skill and confidence, coupled with key reservoir characteristics to re-define the flood management operation in terms of forecasted runoff. Success in balancing multi-objective reservoir purposes means optimizing when possible for water supply and flood management. This “forecast decision making” flood management attitude has potential for a wide range of benefits. Significant advantages include allotment time for flood preparation and ability to recover water supply storage after storm events. A collaborative team of agencies consisting of the U.S. Army Corps of Engineers, U.S. Bureau of Reclamation, Sacramento Area Flood Control Agency, California Department of Water Resources, and the National Weather Service integrated the new flood management paradigm into a revised Water Control Manual. This presentation highlights key characteristics that enable forecast informed flood management, illustrates storm event routings with advanced or pre-storm reservoir releases, and demonstrates rules which accommodate forecast variability.