Lake Oroville Update - April 18, 2025

Stopping the Spread of Golden Mussels 

With the introduction of highly invasive golden mussels into 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. Watercraft inspections at Lake Oroville and the surrounding SWP facilities are expected to begin within the next month. More details will be released soon about the inspection and decontamination program.

 

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 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 before launching into another body of water.

 

Flood Control Releases from Lake Oroville Ongoing

As snowmelt season begins, DWR continues to perform flood protection releases from Lake Oroville using the main spillway and Hyatt Powerplant. Releases from Lake Oroville during the spring months help maintain storage capacity in the reservoir to capture runoff from mountain snowmelt, while optimizing storage for the benefit of water supply, recreation, and fish and wildlife enhancement. DWR continues to conserve as much water supply as possible in coordination with the U.S. Army Corps of Engineers (USACE).

 

Between October and June, DWR is required to operate Lake Oroville for flood control under federal Water Control Manual guidelines set by USACE. DWR is also operating under its own Interim Operations Plan (IOP), approved by USACE and the Federal Energy Regulatory Commission. These federal regulations and the IOP establish an expanded 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 USACE and other downstream water operators.

 

Current reservoir levels are as follows, though estimates may change quickly:

• Current Oroville Reservoir Level: 880 feet elevation
• Current Storage Capacity: 91 percent
• Total Releases to the Feather River: 6,000 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.

 

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 to 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. 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.

 

Visitor Center Art Show

Celebrate Earth Day this month with DWR and the Lake Oroville Visitor Center. The Visitor Center is currently accepting wildflower-inspired artwork from Butte County residents of all ages. Submissions can range from photography and painting to digital art, drawing, or textiles. Submit your work by 2 p.m. on Wednesday, April 23. Artwork will be displayed in the Visitor Center’s front lobby from Saturday, April 26 through Sunday, May 11.

 

In addition, DWR is hosting an Earth Day event at the Lake Oroville Visitor Center on 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.

 

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.

 

Current Lake Operations

Lake Oroville is at 880 feet elevation and storage is approximately 3.13 million acre-feet (MAF), which is 91 percent of its total capacity and 119 percent of the historical average.

 

Feather River flows are at 1,000 cfs through the City of Oroville with 5,000 cfs being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 6,000 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 4/17/2025.

 

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