The San Francisco Public Utilities Commission (SFPUC) is proposing to use a Sunol gravel quarry as a water recapture pit as part of environmental mitigation for its Calaveras Dam expansion project.

SFPUC, which operates the San Francisco water system, is in the process of taking public comments for a draft EIR on the project.

A scoping meeting to take questions for a draft EIR was held July 9 at Sunol Glen School, It was attended by a few Sunol residents and representatives of the Alameda Creek Alliance. The San Francisco planning department is conducting the EIR process.

Save Our Sunol (SOS) vice president Jim O'Laughlin said that two points were raised. One addressed what the project might do to the underground water basin in the Sunol Valley. Another consideration was whether there would be any effect downstream in Alameda Creek in Niles Canyon.

SFPUC wants to use the formerly active Mission Rock Quarry, east of Interstate 689, where mining ended in 2007. The pit has water in it naturally from the aquifers around it, and can store up to 8200 acre feet of water at any one time. SFPUC is proposing an annual storage of 9800 AF, an average annual total.

San Francisco is obligated by a previous agreement on its Calaveras Dam project to put as much water back into Calaveras Reservoir as it takes out, said Ellen Levin, deputy manager for the city's water enterprise. The water will go through a diversion tunnel. A fish ladder will be built over it to accommodate migration of steelhead and other fish.

Levin said that San Francisco has a profile of the Sunol Valley underground basin, and will undertake the proper research to answer questions about any impacts. However, she expects there would be no change from current use, since the same pit will be used.

Most of the Sunol Valley obtains its drinking water from San Francisco. Kilkare Canyon residents take water from a Pleasanton pipeline.

Anyone wishing to send comments for the draft EIR may do so by wrting to Sarah B.Jones, San Francsico Plannng Deparmtne, 1650 Mission St., Suite 400, San Francisco, CA., 94103. E-mail may be sent to Sarah.B.Jones@sfgov.org.