“Work has begun on a tunnel that is part of a project to safeguard the drinking water supply of more than 2 million San Francisco Bay area residents in case of an earthquake.
“The 3.5-mile New Irvington Tunnel will run from Sunol to Fremont’s Mission San Jose district. Officials say the existing Irvington Tunnel, which connects several pipelines bringing water from the Sierras, is susceptible to heavy damage during an earthquake.
“The Oakland Tribune reports that crews have so far tunneled about 100 feet at a rate of 22 feet per day. The $227 million tunnel is expected to be completed in 2014.
“It is part of the San Francisco Public Utilities Commission’s $4.6 billion effort to upgrade the system that draws water from Yosemite National Park’s Hetch Hetchy Reservoir and serves 2.4 million customers in four Bay area counties.”
Read more: Mercury News