Friday, June 28, 2013

Series #2 Do you Know Your Tap Water? – Local Waters

Second in our series of ‘Do you know your tap water’, begs the question, OK, 85% from Hetch Hetchy, straight through the Sunol Valley to our customers… but what about the rest?


The rest of the water supply comes from local reservoirs. In the Sunol Valley that includes two: Calaveras and San Antonio Reservoirs. Calaveras, when full, is our system’s second largest drinking water reservoir, second only to Hetch Hetchy Reservoir. It also stores only local watershed waters from the Arroyo Hondo and Alameda Creek. San Antonio Reservoir, on the other hand, stores water from San Antonio Creek, and we can also store Hetch Hetchy water there as well.

Calaveras Reservoir, shown here prior to the start of construction of the Replacement Calaveras Dam, stores local water only.

 San Antonio Reservoir Stores both Local Watershed Waters and Hetch Hetch Hetchy Water

We must filter the water from these local reservoirs at our Sunol Valley Water Treatment Plant before we send it to our customers.

Some facts about local dams and reservoirs that you may not know:

• The dam at San Antonio Reservoir is called Turner Dam, after former SFPUC General Manager, James H. Turner.

Turner Dam

• When originally constructed in 1925, Calaveras Dam was the largest earth-fill dam in the world.

Existing Calaveras Dam. The New dam is being constructed directly downstream of the existing one. The site looks very different today!

• Both reservoirs support habitat for many rare and endangered species. Each reservoir also has a nesting pair of bald eagles. Learn more about them here.

Catch up on the Do you know your Tap Water series.

See you around Sunol Valley!

1 comment:

  1. Local water is so important for the local community. And then im thinking about that the water is not contaminated. And the water is fresh.