As it manages storm inflow to Lake Oroville with a main spillway damaged by erosion, the California Department of Water Resources (DWR) announced late Thursday that the reservoir’s emergency spillway likely will be used, perhaps as soon as the early hours of Saturday.
In that event, total discharges from the reservoir would be consistent with flood control releases at this time of year under these weather conditions. DWR does not expect the discharge from the reservoir to exceed the capacity of any channel downstream as the water flows through the Feather River, into the Sacramento River and on to the San Francisco Bay. Inflow to Lake Oroville was expected to peak late Thursday and begin to decline through the weekend.
Oroville Dam itself is sound and there is no imminent threat to the public, said DWR Acting Director William Croyle.
“We and our many partners are doing everything we can to minimize all risks to the public and the dam,” he said.
The emergency spillway has not been used in Oroville Dam’s 48-year history, but Lake Oroville came within a foot of spilling into it in January 1997.
The emergency spillway is a vegetated hillside near the dam, and should it be used, water would wash away large amounts of soil. In preparation for the possible use of the emergency spillway, trees and brush are being removed from the hillside to minimize any flow of debris into the river. Evacuation of fish from a downstream hatchery is underway to avoid harm to young fish and eggs from turbid water.
DWR is coordinating closely with state and federal wildlife and dam safety officials as it responds to the spillway erosion and manages reservoir operations. Those involved in contingency planning and response include the Federal Energy Regulatory Commission, the U.S. Army Corps of Engineers, Butte County Sheriff’s Office, the Governor’s Office of Emergency Services, the state’s Division of Safety of Dams, CAL FIRE and state and federal wildlife agencies.
Lake conditions, including lake levels, inflows, and outflows can be obtained via a recorded message at 530-534-2307. More information is available here.
Friday, February 10, 2017
DWR: Oroville Dam spillway could be ready by Saturday
From a news release: