By Chris Cooney
Bay City News Service
The San Francisco Public Utilities Commission has launched a $320 million upgrade to safeguard the region's water supply in the event of a major earthquake.
The project is part of the SFPUC's $4.6 billion Water System Improvement Program to seismically upgrade the entire Hetch Hetchy water system, which includes 81 separate construction projects along the water delivery system that stretches from Yosemite National Park to San Francisco.
SFPUC General Manager Ed Harrington joined San Mateo County Board of Supervisors President Carole Groom at the edge of Lower Crystal Springs Reservoir on Wednesday to launch four retrofit projects on the Peninsula, including the upgrade of a 19-mile water transmission pipeline between the reservoir and the southern city limit of San Francisco, and improvements to the Lower Crystal Springs Dam.
The seismic improvements are designed to allow the SFPUC to return minimum water service to one million people in San Mateo and San Francisco counties within 36 hours of a major earthquake.
The U.S. Geological Survey has stated that there is a 63 percent chance that a major earthquake will strike on a Bay Area fault within the next 30 years.
"The San Andreas Fault is about 1,000 feet out, right in the middle of this lake," Mr. Harrington said, standing in front of the Lower Crystal Springs Reservoir.
Seismic work on the Lower Crystal Springs Dam will only be to the structure's spillway and a protective wall at the waterline, he said, not to the dam itself, which is still considered to be seismically sound more than 120 years after it was built.
The dam was constructed in 1890 and survived major earthquakes in 1906 and 1989.
"It's had its first field tests," Mr. Harrington said.
The Hetch Hetchy improvement program is being paid for by the issuance of municipal bonds and by ratepayers, SFPUC spokeman Tyrone Jue said.