Dam Project Will Secure County Water in Case of an Earthquake

The San Francisco Public Utilities Commission launched a $320 million construction project Wednesday at Lower Crystal Springs Reservoir that will protect the Peninsula’s drinking water in case of a major earthquake.

The dam upgrades will provide San Mateo and San Francisco County residents with water within 36 hours of a catastrophe, whereas the current dam structure could disrupt water supply for 30 to 60 days, according to officials.

“Our communities cannot survive for that long without a reliable water source,” said SFPUC Commissioner Art Torres.

The Lower Crystal Sprigs Dam was built in 1890, and served as a design model for the Hoover Dam. The seismic retrofit to the dam is part of a $4.6 billion program that includes upgrades to the Hetch Hetchy Regional Water System, which carries water from Hetch Hetchy Reservoir in Yosemite National Park.

The enhancements, required by the California Division of Safety of Dams, will raise the height of the existing parapet wall at the top of the dam by 9 feet and widen the dam’s spillway. In case of a flood, these improvement will secure water diversion to San Mateo Creek.

“The devastating earthquake in Japan is a sobering reminder of the need to have a seismically secure and reliable drinking water system,” said SFPUC General Manger Ed Harrington.

This public works project is currently one of the largest in the U.S. and the largest in California, according to Harrington. 

During construction, part of the Sawyer Camp Trail, a 6-mile walking and biking path, will be closed for short periods.