Work Set to Proceed on Mountain Tunnel Improvements Project

The SFPUC is set to begin construction work on the Mountain Tunnel Improvements Project, a multi-year effort to upgrade and rehabilitate a critical component of the SFPUC Regional Water System that serves 2.7 million customers in the Bay Area. “The water we provide our customers passes through miles of pipelines and tunnels before it reaches taps in…

A Look Back in History: Life at the Dam

A gem from the Hetch Hetchy construction contract No. 61 proposal is a plan showing proximity of the construction crew camp to the proposed dam site. In the lower left quadrant of the drawing, the tramway location is reaching down from the loop of Hetch Hetchy Railroad upslope. Other interesting features in the drawing depict…

A Look Back in History: Bedrock Contour Map of Hetch Hetchy Dam Site

The original O’Shaughnessy Dam was 226 feet above riverbed. It was raised from its original height in 1938. Today the O’Shaughnessy Dam is 312 feet above riverbed and 430 feet above bedrock. Below is a bedrock contour map developed for the dam. This illustration is taken from Contract No. 61, “For the Construction of Hetch…

How a Little-Known Powerhouse Keeps San Francisco Running

Moccasin Powerhouse is situated near the base of beautiful rolling hills along a creek in Tuolumne County 130 miles east of San Francisco. Unbeknownst to many a visitor passing by, it is a vital resource in the City & County of San Francisco’s Regional Water and Power System. One of three hydroelectric power plants operated…

A Look Back in History: Hetch Hetchy Dam Factoids

The photograph below is the cover to Contract No. 61 of the San Francisco Department of Public Works. The contract is for the construction of Hetch Hetchy Dam. Notice that it is the “Proposal form” of the contract. This contract includes 98 pages of text and 46 pages of drawings. Going through the pages, it…