Straight To The Source

On a recent trip to Yosemite, I found myself staying in a lodge just a few miles from the Hetch Hetchy Reservoir & O’Shaughnessy Dam, so we decided to head into the valley to check out the source of our daily shower & drinking water, as well as much of San Francisco’s electricity.

O'Shaughnessy Dam

The Dam, completed in 1923 (with an additional 85 feet added in 1938), provides power for all of San Francisco’s municipal needs, including (but not limited to) General Hospital, San Francisco International Airport, City Hall, and Muni’s electric vehicles (streetcars, LRVs & trolley buses).

It also provides 85% of the City’s water, which is delivered by gravity through 150 miles of pipelines and tunnels that stretch from the Sierras to San Francisco. Because the water is so pure, it’s one of only a small number of city water supplies in the country that doesn’t require filtering.

The Dam & Reservoir are owned by the City & County of San Francisco and operated/maintained by the San Francisco Public Utilities Commission.

Although strongly opposed by John Muir & The Sierra Club for the irreparable harm it would have on the natural beauty of the valley, not to mention the difficulties it would create for the Yosemite-Mono Lake Paiutes Indians, the Dam’s construction was approved by Congress in 1913 with the passage of the Raker Act.

The removal of the Dam and restoration of Hetch Hetchy Valley has long been advocated for by organizations such as The Sierra Club, the Environmental Defense Fund & Restore Hetch Hetchy, but surprisingly it’s been Republican politicians that seem to have taken up the cause over the last few decades. One of the first studies on its removal was commissioned in 1987 by then Secretary of the Department of the Interior under President Reagan, Don Hodel. More recently, in 2007, President Bush proposed a $7 million study, and in 2006 Governor Schwarzenegger deemed its removal “feasible”. However many, including Senator Dianne Feinstein and the City & County of San Francisco, remain staunchly opposed to its dismantling.

The Hetch Hetchy Valley Floor in 1908. Photo: The Sierra Club

Hetch Hetchy Valley today.

With proper funding and motivation, I believe the water & power from the Dam & Reservoir could be replaced with other renewable/local sources, allowing Hetch Hetchy Valley to be restored to its original grandeur. Unfortunately, doing so would take far more political will and financial capital than is likely available in the current climate.

In the meantime, I’ll continue enjoying the most delicious tap water a city dweller can find.


Filed under Environment, General, History, Infrastructure

4 responses to “Straight To The Source

  1. Great background and photos Brendon. It seems feasible, if the political will is there. What are the benefits or expected benefits, of restoring it to its pre-dam condition?

    • I believe the main benefits would be to the plant-life, animals and insects that would return to the Valley. There would also be the ascetic improvements to the Valley, however a more scenic locale could encourage more tourists to visit the area, which could potentially have a negative impact. One of the benefits of the dam & reservoir is that they make it one of the least visited parts of Yosemite, which helps protect some of the natural beauty & environment. Restore Hetch Hetchy ( does mention this issue, and it sounds like they’ve thought of many ways to help mitigate that impact and prevent Hetch Hetchy Valley from becoming as touristy/car-choked as Yosemite Valley.

  2. Great post! Didn’t have a clue how San Francisco got it’s drinking water before that!

  3. Harrison

    There’s an excellent book that came out a few years ago- called Imperial San Francisco: Urban Power, Earthly Ruin- that treated the water supply issue at some length. Laid out a pretty solid case that the connection of water supply to real estate value makes it unlikely that the dam would be torn down.