Raging California wildfire

Nearly 3,700 firefighters were on hand Monday as the northern California wildfire burned for a tenth day. Stretching 230 square miles (600 square kilometers), the so-called Rim Fire is the biggest on record in the Sierra Nevada region.

Local news media reported Monday that the blaze had come within five miles from the Hetch Hetchy Reservoir, the primary source of drinking water for the San Francisco Bay Area's 2.6 million residents. Officials were monitoring the facility, located approximately 150 miles from the city, which pumps water through a newly-opened $4.6 million (3.4 million euros), gravity-operated pipeline system.

Water still 'good quality'

"We're taking advantage that the water we're receiving is still of good quality," said Harlan Kelly Jr., general manager of San Francisco's Public Utilities Commission. "We're bringing down as much water as possible and replenishing all of the local reservoirs."

Utility officials said they had sixth-month supply of water in reservoirs near the city. They added that the ash near the Hetch Hetchy facility is non toxic, but the water could be filtered if necessary.

Although the fire was still some ways away from the reservoir, authorities were monitoring hydroelectric transmission lines and other utility facilities in the area.

Power generation at the reservoir was shut down last week to protect firefighters from live wires, and San Francisco has been buying power from other sources. California Governor Jerry Brown has declared a state of emergency for the city because of its threatened water and power supply.

Massive fire

The California Department of Forestry and Fire Protection, Cal Fire, said Monday that the blaze was 15 percent contained, up from 7 percent the day before. Almost 150,000 acres (60,000 hectares) have been burned so far and some 4,500 buildings are still under threat.

"Winds again today will pose a challenge with gusts of 26 miles per hour (42 kilometers per hour) out of the south, pushing the fire further to the northeast," said an official update.

A number of nearby schools were closed on Monday; however most of Yosemite National Park remained open to visitors.

Rough terrain and heavy winds have combined with extremely dry conditions to make fighting the fire especially difficult. A cause for the blaze has yet to be determined.

dr/jr (AP, AFP, Reuters, dpa)