USACE Set to Take Full Control of Isabella Dam Water Releases

The U.S. Army Corps of Engineers Sacramento District will begin the process early Thursday morning to take full control of water releases from Isabella Lake as temperatures heat up.

Beginning at approximately 12 a.m. Thursday, operators will begin a phased process to briefly stop the release of water from Isabella Lake into Isabella Partners’ hydropower plant at the foot of the main dam. Once releases have stopped, power plant operators will drain the conduit and fully open the plant’s gates. Then dam operators will begin releasing water again, gradually increasing the outflow to the current target of approximately 6,200 cubic feet of water per second.

Isabella Reservoir is located forty miles northeast of Bakersfield, Kern County, California, and consists of an earthfill main dam and auxiliary dam across Kern River and Hot Springs Valley, respectively. In September 2017, the Corps awarded a $204 million contract to Flatiron/Dragados/Sukut Joint Venture of Benicia, California, to construct the Phase II dams and spillways modifications. Phase II reached completion in late 2023. (U.S. Army Corps of Engineers photo)
Isabella Reservoir is located forty miles northeast of Bakersfield, Kern County, California, and consists of an earthfill main dam and auxiliary dam across Kern River and Hot Springs Valley, respectively. In September 2017, the Corps awarded a $204 million contract to Flatiron/Dragados/Sukut Joint Venture of Benicia, California, to construct the Phase II dams and spillways modifications. Phase II reached completion in late 2023. (U.S. Army Corps of Engineers photo)

This flood risk reduction measure will enable USACE to fully control the rate at which controlled water releases enter the Kern River ahead of increased temperatures and reservoir inflows due to snowmelt runoff. Currently, the hydropower plant controls that rate.

It will take approximately six hours to stop flows through the hydropower plant, with releases expected to be reduced by 1,000 cfs each hour. After power plant operators evacuate the conduit and fully open the hydropower plant gates, USACE will restart releases at 500 cfs and will increase outflow by 500 cfs per hour for about 12 hours, or until the release reaches the target outflow.

USACE strongly discourages activities in or around downstream waterways because currents are expected to fluctuate significantly, increasing danger for anyone in the water or along banks.

USACE continues to coordinate controlled water releases with local and state agencies to add flood control space in our reservoirs and to help reduce the impacts of snowmelt runoff or potential future precipitation. Our number one priority continues to be the life, health, and safety of the public.

For emergency information and planning resources, please visit:
Kern County Emergency Plans: https://kerncountyfire.org/education-safety/emergency-plans/
Kern County Emergency Alert Program: https://kerncountyfire.org/education-safety/ready-kern/
California Governor’s Office of Emergency Services: www.caloes.ca.gov

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