Water in the West- Hetch Hetchy Reservoir- California

We visited the Hetch Hetchy Reservoir on June 27, it is winthin Yosemite National Park. Becasue Hetch Hetcy is a municipal water supply and the water is not filterd (the Tuloumne is a protected watershed) swimming and boating are prohibited. Fishing is pemirtted formt he lake shore.

The Reservoir, harming wilderness? what! Isn't it beautiful.

Photo Credit: Eric Robinson

The reservoir holds 360,000 million acre feet of water, very small compared to Lake Powell and Mead.
The O'Shaughnessy Dam 364 feet talls form the reservoir and is gravity fed. There was a long battle against the dam, led by famous John Muir.

O'Shaunghnessy Dam.

Photo Credit: Eric Robinson

The Raker Act signed by President Woodrow Wilson in 1913 allowed San Francisco to buy the rights to the Tuolomne River and begin construciton of the dam that wasn't complete till 1923.  Wait when did San Francisco get invovled? The primary purpose of the dam was to supply fresh drinking water to the San Fran. Bay Area.  Hethc Hethcy holds 25 % of the cities water supply.

Hydroelectric power is also produced from the dam by the  Moccasin Powerhouse, which has a capacity of 100 megawatts. We had a tour of the Moccasin faciliy by Dr. Bruce McGurk.

San Francisco Public Utilites Comission Water System Hetch Hetchy to San Fran.