Application of forecast-informed reservoir operations at US Army Corps of Engineers dams in California

Abstract

The US Army Corps of Engineers (USACE) prescribes flood control operations for reservoirs it regulates in watershed-specific water control manuals (WCMs), which can be decades-old and may not capture changed conditions in the watersheds or include the benefit of state-of-the-science weather and streamflow prediction. Considering the specific characteristics of a reservoir, forecast-informed reservoir operations (FIRO) may be used to enhance flood risk reduction, improve water availability, and achieve other benefits. The first FIRO pilot project at Lake Mendocino in California focused on determining if water supply reliability could be improved using FIRO without increasing flood risk. The final report concluded that FIRO concepts could indeed improve water supply reliability while enhancing flood risk reduction. Subsequently, USACE chose additional reservoir systems in California with different characteristics as additional pilot study locations to further investigate FIRO concepts. These successful FIRO efforts have provided justification to continue its expansion beyond the initial pilot sites. The lessons learned from the FIRO pilot projects are being used to inform the development of the FIRO Screening Process, a screening level framework intended to scale up the implementation of FIRO. The lessons learned could support FIRO implementation at suitable USACE reservoirs by updating WCMs.