Hetch Hetchy water restoration system upgraded

March 30, 2011 7:00:50 PM PDT
The next phase in a major overhaul of San Francisco's Hetch Hetchy water system is aimed at restoring water service to millions of Bay Area residents in 24 hours, not months, following a major earthquake.

The $320 million project will provide upgrades to the Crystal Springs and San Andreas reservoirs, which sit west of Interstate 280 on the Peninsula, to pipelines, and to a water treatment plant west of Millbrae. The work will take four years to complete.

The Hetch Hetchy system, which is owned and operated by the San Francisco Public Utilities Commission, supplies water to San Francisco and to 1. 7 million other customers in Alameda, San Mateo and Santa Clara counties. The two main reservoirs sit on top of the San Andreas Fault.

Officials from multiple agencies and communities gathered this morning next to an outlet tower, which covers a pipeline that drafts water from the reservoir destined for a treatment plant. That tower, along an older one to the south, will both be demolished and submerged as part of the upgrade project. The public is barred from the watershed, although a popular trail for cycling, walking and jogging runs along the reservoir.

The Lower Crystal Springs Dam, which provides a spillway for water to be released down a creek leading to San Francisco Bay, is not being upgraded. Built in 1890, it withstood the 1906 and 1989 earthquakes without damage, and officials say it is seismically safe. However, the spillway will be modified and additional work done to provide additional water storage to prevent flooding during water discharge.

A major pipeline stretching 19 miles from the dam north to San Francisco will be replaced, along with improvements at the Harry Tracy Water Treatment Plant and the transmission system.

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