Yuba Water Agency today launched an initiative with the California Department of Water Resources (DWR) and University of California San Diego’s Scripps Institution of Oceanography to improve storm and runoff forecasting, and significantly reduce flood risk though enhanced operations of New Bullards Bar and Oroville dams.
This research will supply information needed for the U.S. Army Corps of Engineers to update the 1970’s-era water control manuals, which dictate the storm-season operations of both reservoirs. Yuba Water’s goal is to have a new water control manual approved about the same time the agency completes construction of a new, planned secondary spillway at its New Bullards Bar Dam, estimated for completion in 2024.
“The updated manuals, combined with the planned secondary spillway at New Bullards Bar, will help us maximize the value of that critical infrastructure improvement, enabling us to respond to changing climate conditions,” said Yuba Water Agency General Manager Curt Aikens. “This will significantly improve our ability to operate the project in extreme events, and help us more efficiently manage water for local farmers, ranchers and fisheries, as well as the 80 percent of Yuba County’s population that relies on groundwater for their primary water supply.”
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. Currently, dam operators are required to keep the reservoir at a significantly reduced water level during storm seasons, ensuring enough space to handle possible storms, regardless of the forecast, even during drought.
“We’re excited to partner with Yuba Water Agency to modernize how our facilities are operated in this new reality under climate change. It’s important we collaborate as our infrastructure is part of a larger system and cannot operate in isolation,” said DWR Director Karla Nemeth. “As California continues to adapt to the impacts of climate change, preparing our water system for intense storms and periods of drought is more critical than ever.”
The $1.95 million contract with Scripps will fund a three-year research program into how atmospheric rivers (also known as “Pineapple Express” storms) impact flood flows in terms of snow line, snow melt, storm location, duration and intensity, as well as improving data collection for better forecasting. The contract costs will be split evenly between Yuba Water Agency and DWR.
Yuba Water Agency already partners with DWR, the Army Corps and National Weather Service on the Forecast-Coordinated Operations program, to minimize regional flood risk. The agencies all work together to coordinate flood releases during major storms. Forecast-informed reservoir operations will elevate that work to the next level, significantly reducing flood risk. In dry and drought years there is also the potential to improve water supply reliability.
The Yuba Water Agency Board of Directors in 2018 approved $11 million for the engineering design, planning and permitting of the secondary spillway, which will have gates 31.5 feet lower in elevation, allowing the agency to release water in advance of large, threatening storms. But to achieve the maximum benefit of the new spillway, the Army Corps water control manual will require these updates, and this research program with DWR and Scripps is a major milestone in that process.
Yuba Water owns and operates New Bullards Bar Dam and Reservoir and DWR owns and operates Oroville Dam and Reservoir.