Lake Oroville Community Update - December 1, 2023

Salmon Carcass Surveys

Department of Water Resources (DWR) scientists will perform weekly fish carcass surveys in the Feather River through Dec. 22 to record the number of Chinook salmon returning to spawn this season. Approximately two to three boats will be on the river during weekdays conducting carcass surveys. 

 

The weekday carcass survey schedule is as follows, but is subject to change due to crew availability and the number of fish carcasses encountered:

• Monday: Robinson Riffle up to Highway 162
• Tuesday: Highway 70 to the top of the Auditorium Riffle
• Wednesday: Auditorium Riffle to the launch area by the Table Mountain Bridge
• Thursday: Thermalito Afterbay Outlet Boat Ramp upstream to Steep Riffle (near the Fish Monitoring Station); Thermalito Afterbay Outlet Boat Ramp downstream to the G-95 Riffle (near Mile Pond)
• Friday: Gridley Boat Ramp upstream through Hour Bars to the G-95 Riffle (near Mile Pond)

In future years, the carcass survey will be phased out as DWR’s new Feather River Fish Monitoring Station will provide the data necessary to determine the number of Chinook salmon returning to spawn. While some carcass sampling will still occur in the low-flow channel, this will be at a much lower level than current surveying needs.

 

Steelhead Spawning

The fish ladder at the Feather River Fish Hatchery reopened Nov. 30 with steelhead spawning operations beginning around mid-December. Steelhead enter the hatchery via the fish ladder that leads up from the Feather River Fish Barrier Dam and can be seen at the viewing windows and facility. Once the spawned fish eggs have hatched, the juvenile fish will be reared at the hatchery for a full year and then released next winter into the Feather River. If there are any surplus fish beyond the production goal, fish may be planted into the Thermalito Afterbay for recreational fishing.

 

Like the juvenile salmon that populate the Feather River, steelhead trout migrate from freshwater to marine (ocean), returning to freshwater environments to spawn. Unlike salmon, they can spawn several times during their lifetime and can live up to eight years. The “steelhead” name comes from their appearance, a more streamlined shape than Chinook salmon with a silvery or brassy color as an adult.

 

The Feather River Fish Hatchery’s spawning operations enable Chinook salmon and steelhead to be released yearly 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 Nearing Completion

DWR is nearing completion of routine maintenance work on Oroville Dam’s main spillway for the season. Surface concrete work on localized areas of the spillway has been extended through Dec. 8 due to favorable weather conditions.

 

Oroville Dam’s main spillway performed well and operated as designed in 2023, passing over 2,370,000 acre-feet of water – approximately 67 percent of the capacity of Lake Oroville. Due to seasonal temperature variations, spillway releases, and sun exposure, periodic concrete and joint sealant repairs of the main spillway are expected. 

 

Work this year included routine concrete repair, complete sealant replacement on concrete slabs and wall joints, and complete inspection of the 51,000 feet of piping that support 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 the management of these important fish populations. Upstream migrating fish totals between Sept. 11 and Nov. 25 are:

• Chinook salmon: 30,494
• Steelhead: 763

Feather River Fish Monitoring Station net totals are also manually updated weekly on CalFish.org. 

 

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.

 

DWR, State Parks, and the Department of Fish and Wildlife 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. 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.

 

Current Lake Operations

Lake Oroville is at 812 feet elevation and storage is approximately 2.33 million acre-feet (MAF), which is 66 percent of its total capacity and 133 percent of the historical average.

 

Feather River flows remain at 650 cubic feet per second (cfs) through the City of Oroville with 1,100 cfs being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 1,750 cfs downstream. DWR continues to assess releases to the Feather River daily.   

 

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 11/30/2023.