A over Lake Oroville towards Bidwell Canyon Marina and Bidwell Bar Bridge in Butte County, California. On this date, the water storage was 2,243,714 acre-feet (AF), 66 percent of the total capacity. Photo taken September 5, 2024. Xavier Mascareñas / DWR

DWR: Lake Oroville update: Routine spillway inspections scheduled; Geotechnical investigation; Feather River floating classrooms; Current lake operations; and more …

From the Department of Water Resources:

Routine Spillway Inspections Scheduled

Following another wet winter requiring flood control releases from Oroville Dam’s main spillway, the Department of Water Resources (DWR) will be cleaning and performing routine annual inspections of the concrete spillway chute. DWR contractor Syblon Reid will begin cleaning areas of the spillway the week of Sept. 23. Members of the public should expect to see crews using pressure washers, brooms, and small cleaning equipment, followed by engineers traversing the spillway on foot conducting the inspections.

Annual inspections of the main spillway are conducted by DWR engineers. During the inspections, engineers assess the condition of the spillway’s concrete slabs, walls, joint sealant, and dentates (energy dissipators at the base of the spillway structure). Routine maintenance activities are expected this fall based on inspection results and reservoir levels.

The main spillway continues to perform well and operate as designed. 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.

Lakeside Access Road Now Open

Lake Oroville’s water elevation has dropped sufficiently low to allow DWR to reopen the Lakeside Access Road, providing around-the-clock access to the Spillway Boat Ramp and Day Use Area. Construction of Lakeside Access Road was completed in 2022 and provides a direct route to the Spillway Day Use Area from Oroville Dam Crest Road without requiring visitors to pass through the California Highway Patrol (CHP) inspection kiosk. The CHP kiosk will now be closed with Lakeside Access Road’s reopening.

Geotechnical Investigation

Starting Sept. 23, DWR will begin drilling associated with a geotechnical investigation of Parish Camp Saddle Dam located near the Lime Saddle Marina. The investigation will provide below-surface data needed to analyze and study the dam’s foundation. The geotechnical investigation is a recommendation by Independent Consultants as part of routine facility performance and safety reviews (Part 12D) that are reported to the Federal Energy Regulatory Commission (FERC). DWR’s drilling plan was reviewed and approved by FERC and the California Division of Safety of Dams. In addition to the sampling of soil and rock materials, DWR plans to conduct optical and geophysical surveys within select drill holes to further DWR’s understanding of the subsurface geology, rock quality, and foundation properties. DWR anticipates Parish Camp Saddle Dam field work to conclude by early November.

Recreation Facilities Update Following Thompson Fire

DWR and the California Department of Parks and Recreation (State Parks) reopened a few Lake Oroville State Recreation Area trails and facilities this week following damage from the Thompson Fire. The Brad Freeman Trail (also known as Burma Road) that runs along the north side of the Diversion Pool between Cherokee Road and the Spillway Day Use Area is now open. A section of the Brad Freeman Trail between Oroville Dam Crest Road and the Lower Overlook has reopened in addition to a section of the Dan Beebe Trail between the Lower Overlook and Lake Oroville Visitor Center. The Diversion Pool Car-top Boat Ramp off Cherokee Road is also open for public use. DWR and State Parks continue to assess fire impacts to recreation facilities and prioritize recovery efforts. While additional facilities are expected to reopen in the coming months, long-term closures of some facilities are anticipated for repairs and ongoing hazard tree removal.

Closures remain in effect at the following locations for hazard tree removal and repairs:

  • Brad Freeman Trail between the Fish Barrier Dam and Lower Overlook
  • Dan Beebe Trail between the Lakeland Boulevard Trail Access and the Lower Overlook
  • Lakeland Boulevard Trail Access
  • Powerhouse Road Trail Access
  • Potter’s Ravine Trail
  • Potter’s Point Trail
  • Potter’s Ravine Spur Trail
  • Dead Cow Ravine Trail and Gobbler’s Knob
  • North Fork Trail

DWR, State Parks, and the California Department of Fish and Wildlife (CDFW) maintain over 92 miles of trails in the Oroville area. An interactive map of recreation facilities, including open trails 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.

Feather River Floating Classrooms

Feather River Floating Classroom raft tours are returning this fall, and this year they are FREE! Sponsored and developed by DWR, the Floating Classroom program takes participants through Feather River spawning habitat while scientists with DWR and Pacific States Marine Fisheries Commission provide information on Chinook salmon conservation efforts, ongoing and planned research, restoration and monitoring projects, and fisheries management activities supported by DWR’s State Water Project.

Free rafting tours this fall are scheduled each Saturday starting Oct. 5 through Nov. 9. Each Saturday will have multiple floating classroom sessions with limited seats. Tickets are available on a first-come, first-served basis with up to four free tickets available per unique registration. Participants must complete the online risk acknowledgment and liability release form within three days (72 hours) of reservation confirmation or tickets will be forfeited. Reserve your FREE floating classroom ticket on Eventbrite.

Oroville Recreation

Staffed by knowledgeable guides, the Lake Oroville 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.

Lake Oroville is one of the State Water Project’s premier recreational destinations and one of California’s best fishing spots. The lake provides both warm-water and cold-water fisheries. Below the Oroville Dam, the Thermalito Forebay, Thermalito Afterbay and the Feather River offer additional excellent fishing opportunities for Chinook salmon and steelhead. The marinas at Bidwell Canyon and Lime Saddle are open daily and provide a variety of services including a convenience store, gas, boat rentals, and more.

Upstream migrating fish totals through the Feather River Fish Monitoring Station between Jan. 1 and Sept. 11 are:

  • Spring-run Chinook salmon (March 1 through June 30): 7,124
  • Fall-run Chinook salmon (July 1 through present): 10,022
  • Steelhead: 1,018

Current Lake Operations

Lake Oroville is at 794 feet elevation and storage is approximately 2.04 million acre-feet (MAF), which is 60 percent of its total capacity and 104 percent of the historical average.

Feather River flows are at 650 cubic feet per second (cfs) through the City of Oroville with 8,350 cfs being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 9,000 cfs downstream. DWR continues to assess Feather River releases daily.

Releases from Oroville Dam’s main spillway ceased earlier this summer, but water is still being released through the Hyatt Powerplant for power generation, water deliveries, and environmental requirements. When the main spillway is not in use, water may still be seen on the main spillway outlet as the seals on the eight radial gates are not designed to be watertight. The gate seals do not play a role in the structural integrity of the gates. Visitors to Oroville Dam may also notice minor amounts of water flowing from drains built into the emergency spillway. This is normal and expected given 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 9/19/2024.