In California, Thompson Fire impacts Oroville Dam and powerhouse

In California, Thompson Fire impacts Oroville Dam and powerhouse
(An aerial overview of the recently completed Lake Oroville main spillway during Phase 2 of the recovery efforts. Work continues on the concrete cap below the Lake Oroville emergency spillway weir at the Butte County, California site. Photo taken January 24, 2019. Kelly M. Grow / California Department of Water Resources, FOR EDITORIAL USE ONLY)

CAL FIRE/Butte County Fire Department reported on the morning of July 4 that the Thompson Fire near Oroville, Calif., has destroyed four structures, with four firefighters injured, and involves 3,568 acres.

The fire is only 7% contained, and the cause is under investigation.

In its incident report, CAL FIRE/Butte County Fire Department noted that it was a vegetation fire and firefighters were working to strengthen containment and control lines. Over the previous 12 hours, there had been no change in the noted acreage, but expected high temperatures on July 4 increased the chances for fire growth.

Mandatory evacuation orders have been issued for several zones, with evacuation warnings issued for others.

On July 3, CBS News reported that the Thompson Fire impacted operations at Oroville Dam, with California Department of Water Resources officials announcing on July 2 that several State Water Project (SWP) facilities in the area of the Thompson Fire are under evacuation orders – including the Hyatt Powerplant at Oroville Dam.

In addition, PG&E de-energized the high-voltage powerlines and staff have been evacuated, DWR said, but some essential staff have also been relocated to the Thermalito Pumping-Generating Plant, to maintain water operations and monitor fire impacts to DWR facilities.

DWR said there are no risks to the dam structure and precautionary measures – like wetting down possibly at-risk areas and positioning backup generators at key facilities – have been implemented.

In a July 3 statement on X (formerly Twitter), DWR said SWP facilities under evacuation orders include the Hyatt Powerplant, the Oroville Field Divisions’ main office and the Lake Oroville Visitor Center. DWR said it was able to resume Hyatt Powerplant and Oroville-Thermalito Complex operations around 2 pm. Oroville Dam’s main spillway has been closed, with water being released through the Hyatt Powerplant for power generation, water deliveries and environmental requirements.

The SWP provides water to 29 public water agencies and also uses the water for hydropower generation. The SWP is a system of 32 storage facilities, 21 pumping plants, four pumping-generating plants, eight conventional hydroelectric plants and about 700 miles of canals and pipelines. Lake Oroville is the largest storage facility in the SWP, providing water to 27 million Californians and 750,000 acres of farmland, while providing flood protection to downstream communities along with environmental and recreation benefits. Among the SWP generating plants is the 762 MW Hyatt Powerplant at the foot of Oroville Dam.

“DWR staff have performed initial assessments of the SWP facilities and found minor damage to nonessential infrastructure such as fencing or equipment. While the Thompson Fire burnt grasses along the face of Oroville Dam and near the main spillway, there was no damage to the dam or spillway structure and Oroville Dam remains safe.”