The Groveland Community Services District board received an update from GCSD staff Monday on efforts to secure nearly $2 million for constructing a new filtration plant that’s urgently needed to ensure Groveland-area residents have potable water into next year.
GCSD currently purchases water stored in Hetch Hetchy Reservoir under a 1967 agreement with the San Francisco Public Utilities Commission. The water from the reservoir serves 3,300 Groveland-area residents, as well as roughly 2.4 million Bay Area residents.
SFPUC is moving forward with a $10 million project to repair the Lower Cherry Lake Aqueduct that was severely damaged by last year’s Rim Fire, which burned 402-square-miles in the Central Sierra. The aqueduct would allow SFPUC to draw water out of Cherry Lake to supplement the supply in Hetch Hetchy.
The commission is concerned about future water supplies, especially should the drought continue into next year. Hetch Hetchy is currently only about half-full, and the area around the reservoir has received only about 50 percent of average annual precipitation to date. The content of the snowpack that feeds into the reservoir was only 38 percent of normal as of April 1 and has been melting fast ever since.
The problem is that the water out of Cherry Lake doesn’t meet federal water-quality standards for an exemption to filtration requirements due high levels of sediment. Hetch Hetchy water only requires disinfection treatment, because the quality is so pristine thanks to being within a national park and surrounded by granite.
GCSD’s two water treatment plants are not equipped with filtration systems, while the SFPUC’s Sunol Valley Treatment Plant can filter up to 80 million gallons per day.
For the complete story, see the May 6, 2014, edition of The Union Democrat.