Lake Oroville Update - May 2, 2025

Clean, Drain, and Dry Your Vessels

With the discovery of the highly invasive golden mussel in California waterways, the Department of Water Resources (DWR) is developing plans to protect State Water Project (SWP) infrastructure in Oroville while maintaining recreation opportunities at local reservoirs. Golden mussels have not been detected at Lake Oroville, the Thermalito Forebay, or the Thermalito Afterbay, and DWR will be implementing measures to prevent their introduction.

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. 

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, which is expected to begin later this month. Once the inspection program starts, watercraft and trailers will need to be mussel free and 100 percent dry to pass an inspection. This includes, but is not limited to, the live well, ballast tank, bilge, cup holders, low depressions in the hull, anchor storage area, life jackets, bait buckets, ropes or lines, or any area in the watercraft or trailer that can hold water.

Mussel inspections at DWR’s Oroville facilities will be free, with more details about inspection locations, hours of operation, and a future decontamination station to come. Boats that pass inspection will be permitted to launch and also offered an Oroville reentry seal upon departure. An intact reentry seal will allow watercraft to bypass the inspection process on the next visit and launch at any of the three Oroville reservoirs.

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.

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.

Additional details about golden mussels and an informational video are available on DWR’s website.

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 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: 891 feet elevation
• Current Storage: 96 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.

Summer Hours in Effect for Spillway Day-Use Area

As the summer months approach and daylight hours linger, the Spillway Boat Ramp and Day Use Area is now open from 5 a.m. to 11 p.m. All vehicles and trailers are subject to inspection by the California Highway Patrol (CHP) for security purposes. There are five other boat ramps at Lake Oroville that are open and do not entail CHP inspections: Bidwell Canyon, Loafer Point, Loafer Creek, Lime Saddle, and Enterprise.

Upcoming Road Closure for Tree Removal

DWR and its partners at the California Conservation Corps (CCC) and Butte County Sheriff’s Office are closing portions of Canyon Drive for tree and vegetation removal over the next two weeks. Canyon Drive between the Oro Dam Blvd. E./Royal Oaks Dr. intersection and Oroville Dam Crest Road will be closed to traffic Tuesday, May 6 through Thursday, May 8 between 7 a.m. and 4:30 p.m. The following week, Canyon Drive will be closed between Oroville Dam Crest Road and Royal Oaks Drive (Upper Oroville Dam Overlook) Monday, May 12 through Thursday, May 15 between 7 a.m. and 4:30 p.m. DWR is performing fuel load reduction activities to minimize fire risk in areas surrounding Lake Oroville. Oroville Dam Crest Road will remain open to visitors during nearby tree removal work.

DWR’s Fuel Load Management Plan is dedicated to reducing wildfire risk, enhancing public safety, and improving forest health around Lake Oroville. During vegetation management activities some trails within the Lake Oroville State Recreation Area may be intermittently closed. Trail users should use caution in active work areas and follow all posted signage.

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 CCC, the California Department of Fish and Wildlife (CDFW), the California Department of Parks and Recreation (State Parks), local tribes, and the Butte County Fire Safe Council.

Oroville Recreation Advisory Committee

The Oroville Recreation Advisory Committee (ORAC) met May 2 at the Southside Oroville Community Center. ORAC was established by the Federal Energy Regulatory Commission (FERC) to review and provide recreation plan recommendations for Oroville Facilities owned by DWR. The 13-member committee is made up of representatives from state and local government, recreation groups, and business and community organizations. To obtain a summary of the meeting, send a request to oroville@water.ca.gov.

Current Lake Operations

Lake Oroville is at 891 feet elevation and storage is approximately 3.29 million acre-feet (MAF), which is 96 percent of its total capacity and 120 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 11:59 p.m. on 5/1/2025.