Lake Oroville Update - April 19, 2024

Published: April 19, 2024

Feather River Pulse Flow to Benefit Migrating Fish

With warming temperatures and the mountain snowmelt season underway, the Department of Water Resources (DWR) continues to perform required flood protection releases from Lake Oroville using the Hyatt Powerplant. Releases from Lake Oroville during the spring months help maintain storage capacity in the reservoir to capture runoff, while optimizing storage for the benefit of water supply, recreation, and fish and wildlife enhancement. Over the past week, DWR has further decreased total releases from Lake Oroville to account for reduced inflows into the reservoir. 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.

The information below reflects current reservoir level estimates. Forecasts can change quickly and may affect the estimates provided.

• Current Oroville Reservoir Level: 881 feet elevation
• Current Storage Capacity: 92 percent
• Total Releases to the Feather River: 5,000 cubic feet per second (cfs); will reduce to 3,500 cfs on Saturday

Total releases to the Feather River amount to 5,000 cfs with 650 cfs being routed down the Low Flow Channel through the City of Oroville. An additional 4,350 cfs is being released from the Thermalito Afterbay River Outlet, located 5 miles downstream from Oroville. On Saturday, total Feather River releases will be reduced to 3,500 cfs while maintaining 650 cfs in the Low Flow Channel. Thermalito Afterbay River Outlet releases will be reduced to 2,850 cfs.

Reductions are in anticipation of a pulse flow, a temporary increase in river flow, which is scheduled to start Tuesday, April 23. Pulse flows benefit migrating fish such as juvenile salmon and steelhead, that are traveling downstream this time of year. Pulse flows increase their survival by increasing the speed at which juvenile salmon and steelhead move downstream, reducing their exposure to predators and potential infection from pathogens. Pulse flows during the winter and spring mimic natural river hydrologic conditions that the salmon and steelhead, along with many other Central Valley riverine species, have adapted to over many eons.

Pulse flows were developed in coordination with the California Department of Fish and Wildlife (CDFW) and National Marine Fisheries Service (NMFS) for the benefit of salmon migrating out of the Feather River. During the pulse flow period, the Low Flow Channel will remain at 650 cfs, while total Feather River releases will increase to 6,450 cfs. It is expected that flows will be reduced again by Saturday, April 27.

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. DWR continues to monitor lake levels, weather forecasts, and mountain snow levels to optimize water storage while meeting environmental requirements and allowing for carryover storage into next year.

Oroville Wildlife Area Plantings Support Native and Migratory Birds

The nearly 12,000-acre Oroville Wildlife Area (OWA) in Butte County is a popular stopping place on the Pacific Flyway for migrating and native birds thanks to its preservation as a wildlife habitat and its proximity to the Thermalito Afterbay and Feather River. Under the management of CDFW, nearly 300 acres of grains, grasses, and flowering plants are sown yearly to provide food (forage), shelter, and nesting cover for migratory and native birds. This spring, CDFW has begun the planting season with 60 acres of sunflower and safflower seeds at 16 different locations around the Thermalito Afterbay.

Growing different types of grains, grasses, and flowers provides nutrition for different varieties of birds and wildlife, and safflower and black oil sunflower seeds provide the most energy per pound of any typical birdseed. Both safflowers and sunflowers thrive best in arid climates and dry conditions like those found in the north Sacramento Valley where the OWA is located.

However, planting at the OWA does present a challenge due to a lack of an irrigation system. CDFW staff instead utilize dry-land farming techniques including minimal land tilling, wider than normal spacing, and the selection of crops best suited for the environment. CDFW staff have been planting forage in the OWA for over 50 years and have a successful track record of timing the weather with their plowing and seeding activities to provide a welcome bounty of high-energy food and shelter for the Valley's native birds and migrating visitors.

Brad Freeman Trail Reroute

Heavy rains caused slope failure along a portion of the Brad Freeman Trail near the Hyatt Powerplant, making a quarter mile long trail section unsafe for public recreation. DWR and the California Department of Parks and Recreation (State Parks) assessed impacts to the trail with a decision ultimately made to reroute the trail for continued recreation use. DWR and State Parks opened the newly rerouted trail this week, which now runs along the north side of Oro Powerhouse Road. The trail reroute provides continuous access to the 41-mile-long Brad Freeman Trail loop, offering multi-use recreation for hiking, biking, and equestrians. The nearest access points to this trail segment are the Diversion Pool parking lot off Oro Powerhouse Road and the Upper Overlook Day Use Area on Canyon Drive.

DWR, State Parks, and 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.

Earth Day Activities

Celebrate Earth Day with DWR and the Lake Oroville Visitor Center. Our Visitor Center guides are hosting an Earth Day chalk art event this Saturday, April 20 from 10 a.m. to 3 p.m. Join our staff in creating beautiful chalk art showcasing your love for our planet and its precious resources. The event is open to all ages and chalk will be provided. 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.

Oroville Recreation

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 and is a popular destination for bass tournaments. Below the Oroville Dam, the Thermalito Afterbay and the Feather River offer additional excellent fishing opportunities. 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.

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

• Spring-run Chinook salmon: 75
• Fall-run Chinook salmon: 42
• Steelhead: 794
• Due to higher flows in the low-flow channel of the Feather River between Feb. 26 and March 18, some fish swam over the monitoring station and were not counted in upstream migration totals.

Current Lake Operations

Lake Oroville is at 881 feet elevation and storage is approximately 3.25 million acre-feet (MAF), which is 92 percent of its total capacity and 123 percent of the historical average.

Feather River flows are at 650 cfs through the City of Oroville with 4,350 cfs being released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River release of 5,000 cfs downstream. On Saturday, total Feather River releases will be reduced to 3,500 cfs while maintaining 650 cfs in the Low Flow Channel. Thermalito Afterbay River Outlet releases will be reduced to 2,850 cfs. 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 4/18/2024.

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