UPDATE: Drone video over spillway added.
Collapse of emergency spillway expected, evacuation ordered
Department of Water Resources officials say they expect the emergency spillway at Oroville Dam to fail, and say residents should evacuate northward.
The emergency spillway suffered erosion and could fail, according to DWR. If that happens, the water behind that barrier will comedown the hill and down the river.
Flow through the broken main spillway was increased to 100,000 cubic feet per second in an effort to lower the water level in the lake more rapidly.
The Butte County Sheriff’s Office reports helicopters will be depositing rock-filled containers to strengthen the potential failure point.
Bud Englund, a public information officer for the incident, said downtown Oroville and low-lying areas, including residents along the Feather River from Oroville to Gridley, are being evacuated.
Reporter Andre Byik said Caltrans and the California Highway Patrol have converted the southbound lanes of Highway 70 into northbound lanes to expedite the evacuation. Traffic there is still nearly gridlocked.
An evacuation center has been set up at the Silver Dollar Fairgrounds in Chico. Black Butte Lake west of Orland has also opened up the Buckhorn Campground to evacuees.
Emergency operations centers as far south of Sacramento have been notified, Englund said.
Evacuation orders have also been made in Yuba and Sutter counties.
My local newspaper publishes a scathing editorial of DWR idiocy and mismanagement
Live video here: https://www.facebook.com/KCRA3/videos/10155026580966514/
UPDATE: DWR issued this statement.n their track record so far…not sure its all that reassuring.
OROVILLE DAM, Calif. – The Department of Water Resources has provided an explanation as to why the mandatory immediate evacuations in Oroville and areas downstream are occurring. The concern is that erosion at the head of the emergency/auxiliary spillway issued evacuation orders for residents. The concern is that erosion at the head of the emergency spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville. Those potential flows could exceed the capacity of downstream channels.
To avert more erosion at the top of the emergency/auxiliary spillway, DWR doubled the flow down its main spillway from 55,000 cubic feet per second (CFS) to 100,000 cfs. The next several hours will be crucial in determining whether the concrete structure at the head of the auxiliary spillway remains intact and prevents larger, uncontrolled flows.
Current flows are contained with downstream channels.
Flow over the auxiliary spillway weir began Saturday morning and has slowed considerably. DWR officials expect that flow to stop entirely soon, according to a press release sent at 6:11 P.M. Sunday. This would reduce the erosion on the downstream side of the structure.
DWR officials stress that Oroville Dam itself is sound and is a separate structure from the emergency/auxiliary spillway.
UPDATE: Live view from the State Emergency Operations Center
UPDATE: Drne video shot earlier today: