Forecast-Informed Reservoir Operations (FIRO)
Recognizing the connection between improved weather forecasting and reservoir operations, Yuba Water Agency is implementing Forecast-Informed Reservoir Operations at New Bullards Bar Dam to significantly reduce flood risk on the Yuba River. This is now possible because of the recent and marked improvement in the science of weather forecasting. The National Weather Service can now accurately forecast rainfall amounts five days out, allowing water managers to predict flows up to a week in advance of a storm.
How FIRO Works
Implementing Forecast-Informed Reservoir Operations reduces flood risk and improves public safety by using weather forecasts to determine the optimal releases for a dam in advance of threatening storms. As an atmospheric river or 'Pineapple Express' storm approaches that is expected to impact the Yuba River watershed, operators will determine exactly how much water to release in advance of the storm, while there is capacity in the river channel, thus creating room in the reservoir to store the storm flows.
Currently, dam operators are required to keep the reservoir at a significantly reduced water level during storm seasons, ensuring space to handle possible storms, regardless of the forecast.
Yuba Water is partnering with the UC San Diego Scripps Institution of Oceanography's Center for Western Weather and Water Extremes, the California Department of Water Resources, U.S. Army Corps of Engineers and others on the implementation of FIRO. This work, combined with Yuba Water’s planned Atmospheric River Control (ARC) Spillway, will substantially reduce flood risk, and offer potential water supply benefits as well. The research is focused on the Yuba and Feather River watersheds simultaneously, as New Bullards Bar and Oroville dams are operated in coordination to minimize downstream flood impacts.
Benefits of an ARC Spillway at New Bullards Bar
Implementing this new operational method at New Bullards Bar Dam requires the construction of an ARC Spillway, with gates lower in elevation that the current spillway. If forecasts show a storm targeting the Yuba watershed, operators could create enough capacity by releasing water quickly with the new, larger spillway.
In early 2022, Yuba Water’s board of directors approved a 100 percent design of an open-channel ARC spillway. Yuba Water is now working with a team of engineers to bring the project to a 100 percent design phase and is exploring potential partners to collaborate on this important multi-benefit project.
Updating the Water Control Manual for New Bullards Bar
Yuba Water is simultaneously working with the U.S. Army Corps of Engineers to update the water control manual for New Bullards Bar, which guides storm-season operations of the reservoir. The agencies will release the new rules in conjunction with the completion of the ARC spillway.
Additional Information and Resources
- New Bullards Bar Dam Planned ARC Spillway (PDF)
- Forecast-Informed Reservoir Operations: Reducing Flood Risk and Refining Water Operations in Yuba County (Adobe Spark feature story shown below)