The San Francisco Public Utilities commissioners were updated Tuesday afternoon about the damage and repair efforts at the Hetch Hetchy water and power facilities after the massive "Rim Fire" burned through the Yosemite area.
The fire that started Aug. 17 at the Stanislaus National Forest spread into Yosemite National Park and has charred more than 254,000 acres.
It has been 80 percent contained and full containment is not expected until Sep. 20.
It is the third largest fire in California history.
SFPUC deputy general manager Michael Carlin explained at the commission meeting this afternoon at San Francisco City Hall that only 1 percent of the Hetch Hetchy watershed was affected by the fire.
Since firefighters gained the upper hand, SFPUC crews have been able to access the facilities and assess the damage.
SFPUC general manager Harlan Kelly said Mayor Ed Lee and SFPUC staff took a helicopter ride to see the "devastation" of the fire.
Kelly credited the U.S. Forest Service, local firefighters and other agencies that came together and "helped us through to where we are today."
"We are grateful to all the firefighters on the ground," Carlin said. Some 300 firefighters were based at city-run Camp Mather during the height of the blaze.
The Hetch Hetchy provides water and other services to 2.6 million Bay Area residents.
Two of three hydroelectric powerhouses were initially taken offline during the fire, but the Kirkwood Powerhouse has since been turned back on, while the Holm turbine is still being repaired.
The roof was damaged in the blaze, but no interior equipment was affected, Carlin said. A temporary roof was placed atop the powerhouse.
Power service was not affected, but about $900,000 was spent to purchase alternative energy.
He said as many as 400 of 1,200 power poles were burned, and local power service remains down.
Camp Mather is being used as a base for restoration work with generators providing power there, according to Carlin.
Carlin said he was proud to report that there was no disruption to water and power service to Bay Area customers at any point.
Water quality was unaffected with the turbidity, or cloudiness, continuing to fall within state-mandated levels.
Carlin said the fast-moving fire prompted fire crews to drop retardant but to protect the water quality none of the retardant was dropped near the O'Shaugnessy Dam at the reservoir.
Ash has not been an issue for water quality at the surface level or when taken from a depth of 160 feet, Carlin said.
Contingency plans were set in place to provide water from other utility companies and local reserves, however water infrastructure was minimally affected by the blaze, Carlin said.
Carlin said the recovery process is in the assessment stage, but crews have been felling trees in hazardous positions on main roads and causing erosion problems.
About 200 trees are being felled in the area near the reservoir every day, he said.
As fire damage continues to be assessed, Carlin said it appears the major issues are destroyed electric distribution lines that provide power to the local system and road damage.
He said property insurance should cover most of the costs, estimated to be up to $30 million, and that state and federal recovery funding would come through eventually.
However, restoration work needs to get going before winter rains arrive, he said.
"We are going to have to spend money to protect our facilities before winter comes," Carlin said.
The commission will need to approve a short-term funding plan that comes from reserves. He said the commissioners would be asked in the coming weeks to decide on a financial plan to fund repair work.
Carlin said ratepayers are not anticipated to see any cost increases because of the fire, however depending on where money is taken from it may hinder future emergency responses.
Kelly told the commission the spending recommendations would need to be made swiftly once full assessments were made and the fire danger had fully passed.