Lake Oroville Update - April 25, 2025
Golden mussels during surveys at O’Neill Forebay in Merced County. 
Stopping the Spread of Golden Mussel
With the discovery of the highly invasive golden mussel in California waterways in October 2024, the Department of Water Resources (DWR) has been developing plans to protect State Water Project (SWP) infrastructure while maintaining facilities like Lake Oroville as prime recreation destinations. As temperatures warm, golden mussels are expected to begin spawning, making them a significant threat to the ecological health of all waters of the state, its water storage and conveyance systems, infrastructure, and water quality.
Golden mussels have not been detected at Lake Oroville and DWR will be implementing measures to prevent their introduction. DWR is coordinating with partners at the California Department of Parks and Recreation (State Parks) and the California Department of Fish and Wildlife (CDFW) to implement a watercraft inspection program at Lake Oroville and the surrounding SWP facilities in Butte County. More details will be released soon, with a program expected to begin within the next month.
Golden mussels range from ¾ inches to 2 inches in size and have a light to dark yellowish-brown to brown-colored shell. When golden mussel populations are established, they are difficult to control since they can become very abundant and are easily spread to new waterbodies. Mussel larvae, also referred to as veligers, are microscopic and free floating in infested waters and can be transported in a boat’s live well, ballast tank, or in the bilge if these areas are not completely drained. If left unchecked, golden mussels can alter aquatic ecosystems by filter-feeding on planktonic algae and changing the habitat structure which can damage fisheries, impact water delivery systems by clogging small-diameter pipelines, screens, and filters, and impact recreation by fouling boat hulls and motors and clogging intakes and cooling lines.
To prevent the spread of invasive mussels, DWR routinely monitors for these species and acts to prevent their spread to non-infested waters. When recreating on California’s waterways, always remember to:
- Clean off aquatic plants and animal material from your boat, trailer, and equipment before leaving the ramp or parking lot.
- Drain ballast, bilge, live-wells, and other water-containing devices, and never drain back into the waterway.
- Dry equipment, including bilge, ballast tanks, and live well, before launching into another body of water.
Additional details about golden mussels and an informational video are available on DWR’s website. CDFW also issued a press release last week about a joint effort to stop the spread of golden mussels in California waterways.
Storage Increasing at Lake Oroville
During the winter and early spring months, flood control releases from Oroville Dam ensure the safety of the City of Oroville and downstream communities by reserving storage space to capture high storm inflows while permitting controlled and coordinated releases from the dam. As the warm summer months approach and rain and snowstorms driven by atmospheric rivers wane, DWR transitions from performing flood control releases at Oroville Dam to conserving as much water in the reservoir as possible, while still meeting water delivery and environmental requirements.
DWR has decreased total releases from Lake Oroville to account for reduced inflows into the reservoir while optimizing storage for the benefit of water supply, recreation, and fish and wildlife enhancement. DWR coordinates releases closely with the U.S. Army Corps of Engineers and other water operators and adjusts releases as needed to maintain balance throughout the water system.
Current reservoir levels are as follows, though estimates may change quickly:
- Current Oroville Reservoir Level: 886 feet elevation
- Current Storage: 94 percent of capacity
- Total Releases to the Feather River: 2,300 cubic feet per second
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. DWR continues to monitor lake levels, weather forecasts, and mountain snow levels to optimize water storage while allowing for carryover storage into next year.
Oroville Recreation Advisory Committee
The Oroville Recreation Advisory Committee (ORAC) will hold a meeting on Friday, May 2 at 10 a.m. at the Southside Oroville Community Center located at 2959 Lower Wyandotte Road, Oroville, CA, 95966.
ORAC was established by the Federal Energy Regulatory Commission (FERC) to review and provide recreation plan recommendations for Oroville Facilities owned by the Department of Water Resources (DWR). The 13-member committee is made up of representatives from state and local government, recreation groups, and business and community organizations.
Earth Day Event at the Visitor Center
DWR is hosting an Earth Day event at the Lake Oroville Visitor Center this Saturday, April 26 from noon to 4 p.m. Join our guides in creating beautiful chalk art and craft projects showcasing your love for our planet and its precious resources. Also stop by to view wildflower-inspired artwork from Butte County residents of all ages. Artwork is being displayed in the Visitor Center’s front lobby from Saturday, April 26 through Sunday, May 11.
Located at 917 Kelly Ridge Rd. in Oroville, the Visitor Center is open daily from 9 a.m. to 5 p.m. Staffed by knowledgeable guides, the Visitor Center features interpretive displays on Oroville Dam, area geology, wildlife and habitat, hydroelectric power, and cultural and historical artifacts. View videos in the theater about the construction of Oroville Dam, walk or hike along nearby trails, and visit the 47-foot-tall observation tower that provides unsurpassed panoramic views of surrounding areas. Free guided tours for school and community groups are available by reservation. Parking and admission to the Visitor Center are free.
CAL FIRE Recognizes DWR for Vegetation Management Efforts
In a recent letter to DWR, CAL FIRE Butte County Unit Chief Garrett Sjolund recognized the Department for its vegetation and fire risk reduction efforts throughout the Lake Oroville area, particularly near the Hyatt Powerplant. During the July 2024 Thompson Fire, strong winds began to push the fire along the Feather River and up the canyon towards the Kelly Ridge area, which would have had devastating impacts on local residents, businesses, and public safety.
Ultimately this did not happen, thanks in part to DWR’s previous fuels reduction work along Oro Dam Blvd. E. which caused the fire to slow significantly. Due to lighter vegetation and ladder fuels in the area, surface fuels burned at a much lower rate and reduced spot fire potential.
“It is my opinion that had the DWR not focused effort on fuels reduction along Oro Dam Blvd. E. near Oro Powerhouse Road, the outcome of this incident may have been much different,” noted Chief Sjolund in his letter.
DWR's Fuel Load Management Plan is reducing hazardous fuels and the risk of catastrophic wildfire by thinning vegetation using hand and mechanical methods, accompanied by chipping and controlled burning. By proactively reducing ground fuels, thinning overgrown vegetation, and removing dead and dying vegetation, firefighters have a better chance at suppressing a wildfire. Between early 2013 and June 2024, DWR and its local partners treated or retreated more than 2,500 acres of vegetation.
Vegetation management remains a top priority for DWR and its partners including CAL FIRE, the Butte County Fire Department, the Butte County Sheriff’s Office, the California Conservation Corps (CCC), the California Dept. of Fish and Wildlife (CDFW), the California Department of Parks and Recreation (State Parks), local tribes, and the Butte County Fire Safe Council.
Current Lake Operations
Lake Oroville is at 886 feet elevation and storage is approximately 3.21 million acre-feet (MAF), which is 94 percent of its total capacity and 119 percent of the historical average.
Feather River flows are at 650 cfs through the City of Oroville with 1,650 cfs being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 2,300 cfs downstream. DWR continues to assess Feather River releases daily.
The public can track precipitation, snow, reservoir levels, and more at the California Data Exchange Center. The Lake Oroville gage station is identified as “ORO.”
All data as of midnight 4/24/2025.
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