The following is a regular update from the Department of Water Resources (DWR) on Lake Oroville Emergency Recovery project activities.
Continued Recovery Work
Construction continues at the site by DWR’s prime contractor Kiewit Infrastructure West Co. In the past two weeks, Kiewit has focused on removing the lower 2,000 feet, or lower chute, of the gated flood control spillway (also known as the main spillway.) Kiewit is using excavators and controlled blasting to demolish the concrete slabs and walls of the lower chute.
Kiewit is also removing the last 600 feet of the upper chute, leaving in place the 1,000 feet that leads to the radial gates. This portion of the upper chute has been deemed structurally sound and will not be replaced this year. It will be patched and anchored this year and removed and replaced next year.
Kiewit, last week, began preliminary foundation preparation work where portions of the new lower chute will be constructed.
Kiewit continues to use controlled blasting to break away rock and concrete from the portions of the chute that will be removed and replaced this year.
Kiewit added an additional four drilling crews, bringing the total to seven crews to increase the rate which it demolishes the lower and upper chutes, and the rock slopes adjacent to the spillways.
Safety of workers remains a priority. An emergency construction siren was recently installed and tested. See more information below.
Board of Consultants (BOC) Memo 6
The sixth BOC memo was transmitted to the Federal Energy Regulatory Commission (FERC).
DWR has reviewed the memo and redacted Critical Energy Infrastructure Information (CEII).
The sixth BOC memo is available here, and the role of the independent BOC is explained here.
BOC approval of design
Separate from the completion of its sixth memo, the BOC has also approved DWR’s final design of the reconstruction and repair to the main and emergency spillways.
DWR will manage observed and forecasted reservoir inflow with necessary releases to achieve a safe and reasonable lake level into the fall that takes into account the needs for public safety first and foremost.
DWR will balance the observed and forecasted reservoir inflow with necessary releases to maintain a safe and reasonable lake level into the fall.
This plan is based on public safety first and foremost, as we repair and rebuild the Lake Oroville spillways so they can safely handle flows from winter storms by November 1.
Current lake levels and levels and number of boat lanes available at different elevations are posted here.
We expect the lake to be at or near an elevation of 700 feet by November 1
Memorial Day Weekend Recap
From Friday, May 26, through Monday, May 29, approximately 30,000 people visited the Lake Oroville State Recreation Area and nearby Wildlife Area. The lake level was 825 feet.
Roughly 19,000 on Lake Oroville
Roughly 3,000 on the Forebay
Roughly 8,000 on the Afterbay and in the Wildlife Area
For comparison, last year there were 38,400 visitors and the lake level was 885 feet. In 2015 there were 25,300 visitors and the lake level was 740 feet.
Siren for construction emergencies installed
DWR on Friday tested a siren installed near the main spillway to alert workers on site of a construction-related emergency.
The siren will be tested at noon on the first Friday each month at noon.
This siren is not meant to warn of an evacuation.
Residents should not be concerned if they hear the siren test, and they should not be concerned if they don’t hear the siren test.
DWR is committed to informing the surrounding communities and the general public about the work being done to repair the spillways at Lake Oroville and related impacts to roads, recreation, public access and surrounding infrastructure and ecosystems. These updates will continue through the summer and fall.