December 7, 2013
Yosemite wildfire threatens San Francisco water supply
One of the largest California wildfires in decades roared largely unchecked for a 10th day through forests in and around Yosemite National Park, moving perilously closer on Monday to a reservoir that provides most of San Francisco's water supply.
As of midday, the eastern flank of the so-called Rim Fire had burned to within a mile of Yosemite's Hetch Hetchy reservoir on the Tuolumne River, raising concerns about the possibility of ash contaminating the sprawling artificial lake.
On Saturday, flames had been no closer than 4 miles from the reservoir, which supplies 85 percent of the water consumed by 2.6 million people in San Francisco and several surrounding communities 200 miles (320 km) to the west.
Reservoir samples on Monday showed that water quality so far remained healthy, said Suzanne Gautier, a spokeswoman for the San Francisco Public Utilities Commission.
But the fire has already damaged two of the three hydropower generating stations linked to the Hetch Hetchy reservoir that supply electricity for all of San Francisco's public facilities, such as hospitals and firehouses.
Gautier said the city for now was continuing to draw on reserve power stored for emergencies and purchasing additional electricity on the open market to make up for the difference.
Despite threats to water and power, firefighters have made headway against the blaze, though rugged terrain and the fire's remote location were complicating efforts to subdue the flames, fire managers said.
"There are places where they can't get in," said Mike Ferris, a spokesman for the National Interagency Fire Center in Boise, Idaho. "It's just inaccessible."
As of Monday morning, fire crews working with hand tools and backed by bulldozers and water-dropping helicopters had carved containment lines around 15 percent of the blaze's perimeter, more than double Sunday's figure, though the fire's footprint continued to grow.