Lake Oroville Water Operations

Winter storms and spring snowmelt filled the Lake Oroville reservoir to capacity, an increase of more than 2.5 million acre-feet of water since Dec. 1. The Department of Water Resources (DWR) continues releases from Lake Oroville through the Hyatt Powerplant and Thermalito Afterbay River Outlet. Total releases to the Feather River amount to 3,000 cubic feet per second (cfs), with adjustments being made to manage storage levels along with water quality and flows through the Sacramento-San Joaquin Delta. Over the past week, inflows into Lake Oroville have been in the range of 2,800 to 3,700 cfs and are projected to be in the same range for the coming week.

DWR may intermittently use the main spillway this summer for water releases to manage storage within the Oroville complex or maintain Feather River temperature levels during ongoing river valve outlet system work near the Hyatt Powerplant. 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, which continue to operate as intended. DWR periodically maintains and adjusts the seals during low-reservoir conditions to improve their sealing capability. The radial gates were also last inspected and tested in Dec. 2022.

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

Driftwood and other floating debris on Lake Oroville are expected due to continued water inflows from tributaries and a high lake level, in combination with past wildfires impacting the watershed. Since January, DWR and California Department of Parks and Recreation (State Parks) staff have been collecting, containing, and pulling pieces of wood out of the lake and away from boat launch ramps using boom lines. However, boaters, water skiers, and other water recreationists should take precautions when operating boats on Lake Oroville and should remain alert for floating debris.

The Lake Oroville reservoir is the largest storage facility in the State Water Project (SWP) and supports environmental and water delivery needs to 27 million Californians and reduces flood risks to downstream communities. DWR continues to closely monitor lake levels and will adjust releases accordingly to optimize operations for water storage and environmental protection while allowing for carryover storage into next year.