Oroville Reservoir

Oroville Reservoir
Name	Oroville Reservoir
Location	Butte County, California, Oroville, Feather River
Type	reservoir
Inflow	Feather River (California), North Fork Feather River, South Fork Feather River
Outflow	Feather River (California)
Basin countries	United States
Area	15,810 acres
Max-depth	770 ft
Volume	3,537,577 acre-feet
Elevation	902 ft

Oroville Reservoir is a large storage reservoir in Butte County, California formed by the construction of the Oroville Dam on the Feather River (California). It serves as a central component of the California State Water Project and plays roles in flood control, water supply, hydropower generation, and recreation. The reservoir is adjacent to the city of Oroville and lies within a network of water infrastructure including Thermalito Afterbay and the Thermalito Diversion Pool.

Overview

Oroville Reservoir is a key facility in the California State Water Project, linking to systems managed by the California Department of Water Resources, the Federal Energy Regulatory Commission, and regional entities such as the Metropolitan Water District of Southern California and the Sacramento Valley. The reservoir interfaces with major conveyance works including the State Water Project Aqueduct, Oroville-Thermalito Complex, and downstream nodes like the Sutter Bypass. Surrounding jurisdictions include Chico, California, Gridley, California, and Yuba City, California. The site sits within the historic Sierra Nevada (United States) foothills and intersects hydrologic regions governed by the U.S. Geological Survey and National Oceanic and Atmospheric Administration.

History and Construction

Proposals to impound the Feather River (California) date to early 20th-century plans involving the California Division of Water Resources and influences from figures associated with the Central Valley Project. Construction of Oroville Dam began in 1961 under the auspices of the California Department of Water Resources and was completed in 1968, parallel to other large projects like Shasta Dam and Folsom Dam. The project involved contractors and engineers linked to firms that previously worked on Hoover Dam-era projects and incorporated lessons from events such as the St. Francis Dam failure. The reservoir’s development intersected with policy debates in the California State Legislature and environmental assessments influenced by agencies like the U.S. Fish and Wildlife Service.

Physical Characteristics and Hydrology

Oroville Reservoir occupies a canyon on the Feather River (California), impounded by Oroville Dam, an embankment dam constructed of earthfill and rock. The reservoir’s capacity is among the largest in California (state), with a storage volume of about 3.5 million acre-feet and a surface area near 15,810 acres at full pool. Tributaries include the Oroville-Thermalito Complex inflows, North Fork Feather River, and numerous creeks draining the Sierra Nevada (United States). Hydrologic monitoring is carried out by the U.S. Geological Survey, the National Weather Service, and the California Department of Water Resources for parameters such as inflow, outflow, evaporation, and sedimentation. The facility contributes to regional groundwater recharge processes affecting basins overseen by the California State Water Resources Control Board.

Water Management and Uses

Oroville Reservoir is integral to water allocation across Southern California, the San Francisco Bay Area, and the Central Valley. The reservoir supports irrigation districts like the Butte County Water District and interfaces with urban suppliers including the San Francisco Public Utilities Commission and the East Bay Municipal Utility District. Hydropower generation at the Edward Hyatt Powerplant connects to the California Independent System Operator grid and complements other hydroelectric resources such as Shasta Dam facilities. Flood control operations coordinate with downstream channels including the Sacramento River and the Yuba River confluences, and management is guided by planning frameworks from agencies like the Federal Emergency Management Agency and the California Office of Emergency Services.

Environmental and Ecological Impacts

The impoundment altered habitats of native species such as the Central Valley Chinook salmon and Central Valley steelhead, with downstream effects noted by the National Marine Fisheries Service and the California Department of Fish and Wildlife. Reservoir operations affect riparian zones, wetlands in the Sutter Basin, and migratory corridors recognized by groups like the Audubon Society and the Sierra Club. Water quality issues monitored by the State Water Resources Control Board include temperature, dissolved oxygen, and nutrient dynamics affecting populations of delta smelt and other species central to listings under the Endangered Species Act. Restoration efforts have involved partnerships with organizations such as the Wildlife Conservation Board and university researchers from University of California, Davis and California State University, Sacramento.

Safety, Dam Incidents, and Repairs

Oroville Dam and its auxiliary spillways have been the focus of high-profile safety events, notably the 2017 spillway damage incident that prompted emergency evacuations coordinated with the California Office of Emergency Services and the Federal Emergency Management Agency. Investigations involved the U.S. Army Corps of Engineers, the Federal Energy Regulatory Commission, and independent engineering firms with precedents in reviews of structures like Glen Canyon Dam. Subsequent repairs and retrofit projects were overseen by the California Department of Water Resources with contract work by heavy civil firms experienced on projects such as San Luis Dam rehabilitation. Monitoring continues under protocols informed by the National Dam Safety Program and standards from the American Society of Civil Engineers.

Recreation and Public Access

Recreational uses at the reservoir include boating, fishing, camping, and hiking, with management by entities such as the California Department of Parks and Recreation and local county parks departments in Butte County, California. Anglers target species managed by the California Department of Fish and Wildlife and visits draw outdoor organizations like the American Whitewater and the Boy Scouts of America. Nearby attractions include historic sites in Oroville, trail networks connected to the Sierra Nevada (United States), and facilities coordinated with the U.S. Forest Service in adjacent federal lands. Access and facilities are subject to regulations from the California State Water Project administrative framework and local ordinances enacted by the Butte County Board of Supervisors.

Category:Reservoirs in California