Despite flames and ash falling from the Rim Fire into the Hetch Hetchy Reservoir used by the city of San Francisco, the water remains at quality levels unchanged since before the fire, according to the SFPUC, which manages the 167-mile gravity-powered system.
Even so, the SFPUC has moved water away from Hetch Hetchy and into reservoirs closer to the Bay Area, to Alameda and San Mateo counties, specifically.
As a precaution, the San Francisco Public Utility Commission had started diverting water away from the Yosemite are to reservoirs in Alameda and San Mateo counties to 302 million gallons a day. Typically, the SFPUC divers 275 million gallons to those Bay Area counties.
As the fire moved east on Tuesday toward the O'Shaughnessy Dam, SFPUC officials noted some ash falling on the water there, though they said the water quality is still OK because they draw water from much lower in the reservoir.
On Monday, spokesman Charles Sheehan said crew members successfully repaired hydroelectric turbine at the Kirkwood Powerhouse by clearing trees from along the transmission lines and access roads.
He said more inspections of these lines are needed before they are reenergized and power delivery services can resume. All of San Francisco’s municipal electric customers continue to be fully supplied, Sheehan said, there will be no interruption in electric service.
To replace the lost Hetch Hetchy power, which runs city buses and municipal buildings, San Francisco has spent $600,000 to buy power from others.
The dam is held in by 300 feet of solid concrete and is considered fireproof, and the area from where water is drawn is 268 feet below the surface.