February 11, 2017 – The Department of Water Resources continues to monitor and manage the water flows at the Oroville Dam. Flow over the auxiliary spillway at 2:00 this afternoon was approximately 3000 cubic feet per second (cfs), with peak overflow expected to occur overnight. Peak overflow is expected to range between 6000 and 12,000 cfs. “Oroville Dam is sound and there is no imminent threat to the public,” said DWR Acting Director William Croyle.
Total discharges from the reservoir are 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.
CAL FIRE Incident Management Team #3 is assisting and supporting the Department of Water Resources on managing the incident.
DWR and CAL FIRE crews in past days have been clearing trees and brush from the path water is taking in the auxiliary spillway, which is an unlined hillside. The auxiliary spillway flows are expected to wash soil and debris into the Feather River.
Flows of between 6,000 cubic feet per second (cfs) and 12,000 cfs are expected to flow into the auxiliary spillway for 32 to 58 hours, based on the latest modeling of weather, reservoir inflow and other factors. Those flows will stop once discharge from the lake exceeds inflow. Flows into the auxiliary spillway are far less than the volume of water washing into the lake from the Feather River watershed. That’s because the 16,000-acre surface of the lake acts as a buffer, spreading and attenuating inflow.
In order to help manage reservoir levels, DWR operators also are discharging 55,000 cfs from the damaged concrete spillway and expect to continue to do so. Upward erosion on this closely monitored, gated spillway has slowed considerably.
DWR focused Saturday on ways to get the Hyatt Power Plant at Oroville Dam back in operation, because 14,000 cfs can be discharged from the plant when it is operating, which would help with reservoir management. Power generation was halted when the water levels in the channel that leads from the power plant became high enough to compromise operation. Water levels rose when debris from the eroded concrete spillway piled up in the channel below. The same erosion also threatens the towers that hold the power lines that take electricity from the power plant to the electrical grid; such a connection is needed for the power plant to operate. DWR, Pacific Gas & Electric Company, and other partners are working to safeguard the hydroelectric facility and power lines.
For information on lake conditions, including lake levels, inflows, and outflows, call 530-534-2307. You can also visit the following website http://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action?resid=ORO
Oro-Dam East from Glen Drive to Canyon Drive.
Oroville Dam Crest Road Closed at the left abutment restrooms.
Canyon Drive from Oroville Dam Blvd East to Royal Oaks Drive.
California State Parks has closed off all recreation trails and areas around the Diversion Pool.
Road Blocks/security checkpoints;
Oro-Dam east at Glen Drive
Oro-Dam east at Canyon Drive
Dam Crest Road at Spillway Access Road
Canyon Drive at Royal Oaks Drive
Cooperating Agencies: 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. A total of 250 personnel are assigned to the incident.