Yosemite wildfire grows, threatens reservoir, power station

Updated 1:41 AM EDT, Wed August 28, 2013

Story highlights

NEW: Rim Fire has burned more than 184,000 acres

Road in Yosemite Park will close for several days

Evacuating residents say they're worried about their homes

(CNN) —  

The numbers are staggering and the prospects are scary as a still-growing California wildfire menaces Yosemite National Park and San Francisco’s water supply.

The tourist hotspot Yosemite Valley and its iconic attractions, including the El Capitan rock formation, currently are safe, miles from the Rim Fire’s reach. However, the blaze was on the edge of the Hetch Hetchy Reservoir, which serves 2.6 million customers in the Bay Area.

Water quality remains unchanged, despite ash that has fallen on the 459-square-mile reservoir, because the water is drawn from a depth of 260 feet, the commission said.

The city was already transferring 275 million gallons of water daily from Hetch Hetchy to other reservoirs because Hetch Hetchy is full, but as a precaution, the city increased that amount by 27 million gallons, a Tuesday statement said.

The commission said it was confident the Rim Fire would not affect the reservoir: “Due to the rocky, granite terrain and limited brush along the perimeter of the reservoir, there is little risk for direct water quality impacts.”

The fire could threaten the area’s hydroelectric generators, which provide much of San Francisco’s electricity.

Because of the approaching flames, officials shut down the generators, and the city – more than 120 miles to the west – temporarily is getting power from elsewhere.

“All of San Francisco’s municipal electric customers continue to be fully supplied