Stormwater and snowmelt filled up the reservoir this week, necessitating releases on the spillway to the Feather River. The cement outlet was closed Tuesday after officials noticed water was flowing irregularly. After stopping the flow, engineers found a gaping hole in the concrete chute. By Thursday, the hole had grown to about 45-feet-deep and 300-feet-wide by 500-feet-long, according to a KCBS report.
On Friday the Butte Sheriff released a statement suggesting that an unpaved emergency spillway would likely be used for the first time ever. Crews were clearing trees and brush this week in the event that a release was needed. But during the noon hour Friday, the department posted an update on the flow suggesting that the emergency release is not imminent.
"Water flow over the Oroville Spillway is currently at 65,000 cfs (cubic feet per second). At the current rate of release, and with the current weather forecast, DWR officials do not believe use of the Emergency Spillway will take place," the department wrote on Facebook.
Situated in the western foothills of the Sierra, Lake Oroville is the second-largest man-made reservoir in California after Shasta. It's a key flood-control and water-storage facility within the California State Water Project, and its fresh water releases control salinity intrusion into the Sacramento-San Joaquin Delta and protect the health of fish and wildlife. As of Friday morning, the lake was at 98 percent capacity.
Earlier this week, photos of the damage and chunks of concrete yanked from the mile-long spillway went viral on social media. Engineers don't know what caused the cave-in that is expected to keep growing until it reaches bedrock.
The department 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.
Officials say Oroville Dam itself is sound and there is no imminent threat to the public.
"Despite rumors, no evacuations have been issued at this time due to the Oroville Spillway," the Sheriff's Department posted online Friday.
There's nothing to see here folks, move along.
Since the roads, bridges and power plants are crumbling from decades of neglect, why not the dams?