NORTHERN CALIFORNIA – The California Department of Water Resources on Wednesday offered an update on operations at the Lake Oroville spillways.

On Sunday DWR completed the transition from incident emergency response to incident emergency recovery at the damaged spillways.
 
Officials said emergency recovery includes construction of the main spillway and the emergency spillway throughout the summer and fall.

DWR reported that the main spillway will be operational by Nov. 1 to accommodate flows from winter storms.

Additional work will begin again in 2018 to complete reconstruction of both spillways, the agency said.

DWR said it will begin ramping down outflows from the main spillway on Friday, May 19, at 9 a.m., with outflows expected to stop by Friday afternoon. The gates at the main spillway are closing to accommodate the construction work on the main spillway.
 
“We are making gradual changes to outflows and river levels and will continue to adjust as we balance community concerns, regulatory requirements and Mother Nature,” said acting DWR Director Bill Croyle.
 
DWR said it intends to keep the gates at the main spillway closed for the remainder of the season.
 
Agency officials that, as part of the ongoing site preparation work that is under way – in addition to the upcoming use of the main spillway – some soil and concrete may be dislodged from the spillway structure. This is expected and will not delay construction.

To balance flows in the Feather River, the Hyatt Powerplant flows are expected to ramp up from 5,000 cubic feet per second to 8,100 cubic feet per second at 1 p.m. Friday.
 
Penstock 1 at Hyatt Powerplant is expected to come online after routine and scheduled maintenance early next week. Once Penstock 1 is back in use, Hyatt Powerplant will have the ability to release 13,000 cubic feet per second.

The River Valves Outlet System has the capacity to release an additional 4,000 cubic feet per second should DWR deem it necessary. A contingency plan is in place should reservoir levels require that the main spillway be used once more this spring or summer.
 
The forecast flows downstream in the Feather River will be a gradual transition over four days, beginning at 20,550 cubic feet per second on Friday morning and ramping down to 5,300 cubic feet per second to Sunday, before the outflow is allowed to rise to 9,800 cubic feet per second beginning on Sunday night.

Meantime, Kiewit Infrastructure West Co. – shown in the video above at work at the site on Tuesday – is expected to ramp up construction work on Monday, May 22. DWR said the complete recovery or replacement of the spillways will be done in multiple phases due to the enormity of the project and the time limitations of the construction season.
 
Work has already started on portions of work like road construction and slope stabilization in and around future work areas which needs to be completed regardless of spillway recovery design decisions.
 
The public can watch construction activities through a live feed from two cameras at the site.

Hosted by the California Department of Parks and Recreation, the Lake Oroville State Recreation Area Spillway Live Stream is at www.parks.ca.gov/live/lakeorovillesra_spillway .