Here is a drone view of the Historic Bidwell Bar Bridge and Lake Oroville in Butte County. Photo courtesy of Department of Water Resources

OROVILLE, CA (MPG) - The Department of Water Resources (DWR) continues federally required flood control releases from Lake Oroville to maintain flood protection for downstream communities.

Water is being released through the Hyatt Powerplant for energy production and from Oroville Dam’s main spillway. With wetter watershed conditions earlier last week, Department of Water Resources increased releases to 15,000 cubic feet per second but reduced releases on March 21 as drier conditions returned.

Department of Water Resources continues to conserve as much water supply as possible in coordination with the U.S. Army Corps of Engineers. Releases are subject to change based on ongoing weather conditions.

Between October and June, Department of Water Resources is required to operate Lake Oroville for flood control under federal Water Control Manual guidelines set by the U.S. Army Corps of Engineers. These federal regulations establish a set storage space that is reserved to capture inflows from rain and future snowmelt, while protecting downstream communities from damaging flood events through water releases. Releases to the Feather River are coordinated closely with the U.S. Army Corps of Engineers and other downstream water operators.

Current reservoir levels are as follows, although estimates can change quickly: current reservoir level is at 868 feet elevation, current storage capacity is at 86 percent, total releases to the feather river are at 12,500 cubic feet per second and reducing to 11,500 cubic feet per second on March 16.

Lake Oroville is the largest storage facility in the State Water Project, providing flood protection while supporting environmental and water delivery needs to 27-million Californians. Some water released from Lake Oroville is distributed locally for agriculture benefits, while the remaining Feather River releases flow south through the State Water Project system to reduce salinity effects in the Delta, provide irrigation for crops in the Central Valley and eventually make their way to Southern California. Department of Water Resources continues to monitor lake levels, weather forecasts and mountain snow levels to optimize water storage while allowing for carryover storage into next year.

Planned water fluctuations at the Oroville-Thermalito Complex were coordinated for several locations on the weekend of March 22 and 23 for planned concrete work on the River Valve Outlet System at Oroville Dam. Starting March 21, water levels at the Thermalito Afterbay dropped approximately 3 feet, while water levels at the Diversion Pool and Thermalito Forebay were approximately 1 foot lower than usual. These water level fluctuations are within the standard operating range at these facilities, with water elevations returning to their usual level by the end of last weekend.

The lower water levels within the complex enable Department of Water Resources to continue making progress on the River Valve Outlet System at Oroville Dam. The system is a series of two parallel outlet conduits, each with two valves, which have the capacity to draw water from deep in Lake Oroville for release. The River Valve Outlet System is a critical feature of the dam, providing the ability to discharge cold water to the Feather River to maintain water temperatures necessary for fish health. It also ensures the ability to maintain Feather River flows through River Valve Outlet System releases during drought years, especially if reservoir levels drop below Hyatt Powerplant’s water intake structures.

The California Department of Fish and Wildlife planted approximately 25,000 Eagle Lake Rainbow Trout at Lake Oroville on March 21 to support recreational fishing. Approximately 18,400 trout were planted at Loafer Creek and approximately 6,600 trout were planted at Lime Saddle. The trout were supplied by the Darrah Springs Hatchery and are about 10- to 12-inches in size, sterile and are native to Eagle Lake in Lassen County. More information about Eagle Lake Rainbow Trout is available at wildlife.ca.gov/Fishing/Inland/Eagle-Lake-Rainbow-Trout.

The Christmas Tree Fish Habitat is a project that the Department of Water Resources, the California Conservation Corps, and California Department of Fish and Wildlife installed fish habitat structures earlier this month at Lake Oroville and the Thermalito Afterbay using approximately 1,300 recycled Christmas trees. The trees were collected by Chico Boy Scout Troop 2 and delivered free of charge to the Department of Water Resources by Recology, a local waste management company.

To create the habitats on Lake Oroville and the Thermalito Afterbay, California Conservation Corps team members bundle the recycled Christmas trees together and anchor them in various locations around the lakebed. At Lake Oroville near the Bidwell Saddle Dam area, 744 trees were assembled into 35 structures. At the Thermalito Afterbay, 570 trees were assembled into 56 structures. Anchoring the trees allows them to remain submerged, providing juvenile fish safe refuge, and improving fisheries and recreational fishing opportunities.

For more than 30 years, Department of Water Resources has worked with local groups to construct fish habitat structures, which is one of the longest continuously running warmwater fish habitat improvement programs in the State of California.

Forecast-informed reservoir operations at Lake Oroville can increase region’s resilience to floods, according to a new report released last week by the Center for Western Weather and Water Extremes. The report shows that changes to reservoir operations at Lake Oroville and New Bullards Bar Reservoir can further reduce flood risk for communities along the Yuba and Feather rivers during extreme atmospheric river storm events and potentially benefit water supply during drier periods. The approach, known as Forecast-Informed Reservoir Operations (FIRO), uses improved monitoring, weather and runoff projections to build more flexibility and efficiency into reservoir operations.

In the largest Forecast-Informed Reservoir Operations assessment to date, Department of Water Resources and Yuba Water Agency (Yuba Water) partnered with the Center for Western Weather and Water Extremes at University of California, San Diego’s Scripps Institution of Oceanography and the U.S. Army Corps of Engineers’ Engineering Research and Development Center to evaluate if Forecast-Informed Reservoir Operations could be implemented at both reservoirs to reduce downstream flood risk without negatively impacting water supplies. Lake Oroville is managed by the Department of Water Resources and New Bullards Bar is managed by Yuba Water Agency.

Using historical forecasts, reservoir storage and river flow data, scientists found that Forecast-Informed Reservoir Operations, combined with a planned second spillway at New Bullards Bar, could provide additional flood storage capacity in the Yuba-Feather system and reduce downstream peak flows during prolonged storms such as the 1986 and 1997 floods that devastated Yuba County.

“California’s reservoirs play a critical role in safeguarding our communities from floods and maintaining our state’s water supply, especially as we continue to see more extreme weather events in the form of larger, wetter and more frequent storms and longer, more severe periods of drought,” said Department of Water Resources’ State Climatologist Dr. Michael Anderson. “The Yuba-Feather FIRO Viability Assessment is an important step toward improving flood protection to communities downstream while managing California’s valuable water resources for decades to come.”

Learn more about the Yuba-Feather Forecast-Informed Reservoir Operations Final Viability Assessment in Department of Water Resources' news release available at water.ca.gov/News/News-Releases/2025/Mar-25/Report-Shows-Forecast-Informed-Reservoir-Operations-Can-Increase-Region-Resilience.

Current lake operations entail that Lake Oroville is at 868 feet elevation and storage is approximately 2.96 million acre-feet (MAF), which is 86 percent of its total capacity and 123 percent of the historical average.

Feather River flows are at 4,000 cubic feet per second through the City of Oroville with 8,500 cubic feet per second being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 12,500 cubic feet per second downstream. On March 23, the total Feather River flows reduced to 11,500 cubic feet per second with flows through the City of Oroville at 3,000 cubic feet per second and flows from the outlet at 8,500 cubic feet per second. Department of Water Resources continues to assess Feather River releases daily. 

The public can track precipitation, snow, reservoir levels and more by visiting cdec.water.ca.gov. The Lake Oroville gage station is identified as “ORO.”