Oroville Dam spillway to be tried Friday
March 17, 2017
• State to open patched spillway at 11 a.m.
• First time since February spillway erosion
For the first time since the spillway eroded in February, the Department of Water Resources on Friday will direct water from Lake Oroville over the reservoir’s now-patched spillway.
Releases from the Hyatt Powerplant will be curtailed and then the regular Oroville Dam gated flood control spillway will be opened. The plan is to get underway about 11 a.m.
The Feather River will rise between 10 and 15 feet early Friday afternoon, depending on channel geometry and location. DWR says.
Anglers, boaters, and other river users are advised to be aware of the increase in flows, as the river will become deeper and swifter, it says.
The changes will increase outflows from Lake Oroville to the Feather River from the current 13,300 cubic feet per second (cfs) to 50,000 cfs between 11 a.m. and 2 p.m. and then those higher flows are expected to be maintained.
Outflows and river levels will remain steady for approximately one week before being reduced again. The increased flows will continue to leave sufficient storage in Lake Oroville to take on more water from rain or snowmelt, says DWR.
When water releases eroded a gaping hole in the spillway last month, the dam’s emergency spillway was opened for the first time ever on February 12. The resulting erosion there prompted the evacuation of 180,000 people living in Oroville and other communities downstream of the spillway.
Since that chaotic night, Butte County Sheriff Kory Honea and others in the area’s emergency services have developed a formal evacuation plan that would see Oroville residents at the top of the list, given their close proximity to the dam.