Lake Oroville Community Update - September 22, 2023


A drone view of water levels at the Bidwell Bar Bridge located at Lake Oroville in Butte County. Photo taken March 8, 2023.

A drone view of water levels at the Bidwell Bar Bridge located at Lake Oroville in Butte County, California. Photo taken March 8, 2023.

Oroville Salmon Festival

Join the Department of Water Resources (DWR) at the Oroville Salmon Festival on Saturday, Sept. 23 from 10 a.m. to 4 p.m. for a celebration of the migration of native Chinook salmon in the Feather River. Visit DWR’s booth at the Feather River Fish Hatchery, where we will have educational materials on water safety, salmon coloring sheets for kids, and a salmon head photo opportunity. DWR Guides will also be giving free tours of the Hatchery, where DWR and DFW raise Chinook salmon and steelhead to improve fisheries populations throughout the state.


Other Salmon Festival activities include a pancake breakfast, Motor Mania, Avie’s Place 3K color run, a food and beer garden, Kid’s Zone, and numerous shopping opportunities and vendor booths in downtown Oroville. DWR has also partnered with the Oroville State Theater to showcase videos about efforts to support vital salmon habitat restoration, fisheries health, and population growth.


View the full Salmon Festival schedule at Visit Oroville.


Feather River Floating Classrooms

Join Friends of Butte Creek and DWR scientists for educational floats on the Feather River during the Oroville Salmon Festival on Sept. 23 and each Saturday through Nov. 11. Rafting trips will float through Feather River spawning habitat while DWR scientists provide information on Chinook salmon conservation efforts, ongoing and planned research, and restoration and monitoring projects.


Each Saturday will have three floating classroom sessions with limited seats. Weekend sessions will support free floating classroom events for local schools. Reserve your floating classroom spot on Eventbrite.


DWR Hosts Annual Emergency Preparedness Workshop

DWR’s Oroville Field Division hosted its annual Emergency Action Plan (EAP) review with local emergency responders and government agencies on Sept. 13. The day-long workshop provided an opportunity to review and discuss emergency action plans for the Oroville-Thermalito Complex facilities.


An EAP is a dam owner’s formal plan that identifies potential emergency conditions at a dam and specifies actions to be followed to minimize loss of life and property damage. It includes information that dam owners use to notify local emergency management officials and state and federal dam safety regulators.


The EAP is developed in consultation with local public safety agencies that may be affected by a dam incident. The resulting plan and the dam owner’s approved inundation map informs local jurisdictions as they plan for all types of incidents, and helps local, state, and federal agencies ensure effective emergency response. Inundation maps may be viewed on the Division of Safety of Dams website.


Annual Grebe Survey Complete

During the summer months, a unique bird makes its home in the waters around the Oroville-Thermalito Complex, with a little help from DWR. The Western and Clark’s grebes are aquatic birds with distinctive red eyes and pointed yellow beaks. During the summer, they arrive from the Pacific Ocean to nesting areas around the Thermalito Afterbay in Oroville. The grebes nest in shallow waters, attaching their floating nests to aquatic vegetation under the surface.


Every year since 2004, DWR has established a goal of keeping Thermalito Afterbay water levels more consistent during the birds’ nesting season as part of our commitment to addressing wildlife needs. This year’s annual grebe survey was conducted Aug. 6 with 384 adults and 232 young grebes estimated at the Afterbay.


Hatchery Fish Ladder Opens

Chinook salmon are completing their life cycle and returning home to the Feather River to lay eggs for the next generation of salmon. Spawning activities at the Feather River Fish Hatchery began this week with the opening of the fish ladder on Sept. 15.


Visitors to the Hatchery’s fish barrier dam overlook viewing area can view salmon congregating and jumping in the Feather River and see them up close through the underwater viewing window as they swim up the fish ladder. The overlook is located off Table Mountain Boulevard across from the Hatchery. The fish ladder is expected to remain open through early to mid-July 2024 for viewing opportunities.


The Feather River Fish Hatchery’s spawning operations enable millions of Chinook salmon to be released every spring in the waters of the Feather River, San Pablo Bay, and San Francisco Bay to support Northern California and Pacific Ocean fisheries. DWR owns and maintains the facility and provides funding to the Department of Fish and Wildlife (DFW) for its spawning, rearing, and stocking operations.


Maintenance Work on Main Spillway Underway

DWR is performing routine concrete and sealant repair work on localized areas of the spillway identified during annual inspections. While the main spillway continues to perform well and operate as designed, periodic concrete and sealant repairs of the spillway are expected due to seasonal temperature variations, spillway releases, and sun exposure. In 2023, Oroville Dam’s main spillway has passed over 2,370,000 acre-feet of water – approximately 67 percent of the capacity of Lake Oroville – with flows up to 36,000 cubic feet per second this spring.


Construction work is expected to continue through Nov. 15, but is dependent on weather and Oroville Dam operations. DWR will monitor reservoir levels and weather forecasts closely and will complete repair work early if spillway releases are required for flood control. The construction contract period extends through 2025, permitting the contractor to complete repairs in future dry seasons should the 2023 construction window be limited. 


Approximately 500 square-feet of total concrete repairs are anticipated, representing less than 0.1 percent of the spillway’s surface. DWR will also replace joint sealant at select chute slab and wall joints that wear over time due to the spillway’s environment and inspect 51,000 feet of piping that supports the spillway’s improved drainage system.


The spillway was rebuilt to the highest engineering and safety standards with oversight and guidance by the Federal Energy Regulatory Commission (FERC), Division of Safety of Dams (DSOD), and an independent board of consultants. DWR performed a significant amount of inspection and testing throughout construction to verify compliance with project specifications. DWR also provides regular updates to the Oroville Dam Citizens Advisory Commission, a public forum for discussing operations, maintenance, and public safety activities at Oroville Dam and its facilities.


Oroville Recreation

DWR biologists are using the Feather River Fish Monitoring Station to determine abundance, run timing, and origin (hatchery or natural) of steelhead and Chinook salmon populations. This information will improve management of these important fish populations. Monitoring counts between Sept. 11 and Sept. 15 show a net total of 668 Chinook salmon and 22 steelhead that have passed upstream.


DWR, the California Department of Parks and Recreation, and DFW maintain over 92 miles of trails in the Oroville area. An interactive map of recreation facilities, including open boat ramps, and their permitted uses (hike, bike, horse, multi) is available on DWR’s Lake Oroville Recreation webpage. A paper trail map is available at various locations, including most entrance kiosks and the Lake Oroville Visitor Center. The marinas at Bidwell Canyon and Lime Saddle are open daily and provide a variety of services including a convenience store, gas, and boat rentals.


The Lake Oroville Visitor Center is open seven days a week 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 841 feet elevation and storage is approximately 2.69 million acre-feet (MAF), which is 76 percent of its total capacity and 137 percent of the historical average.


Feather River releases are currently at 7,500 cubic feet per second (cfs). Flows through the City of Oroville are at 650 cfs and releases from the Thermalito Afterbay Outlet (Outlet) are at 6,850 cfs for a total of 7,500 cfs downstream of the Outlet. DWR continues to assess releases to the Feather River daily. 


DWR’s Water Operations division has begun adjusting reservoir levels in accordance with the U.S. Army Corps of Engineers Water Control Manual. This is done each year in preparation for the winter season to provide flood control protection to downstream communities and obtain additional space in the lake for increased storm runoff. Additionally, DWR’s Water Operations division monitors forecasts closely to predict incoming storm impacts and determine whether to release additional water to account for higher estimated inflows.


Visitors to Oroville Dam may also notice minor amounts of water flowing from drains built into the emergency spillway, which is normal and expected with the emergency spillway design. The dam and emergency spillway continue to operate as intended.


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 9/21/2023.