Tuesday, October 21, 2014

Water supply earthquake ready

Retrofit:  New 5 mile tunnel under the San Francisco Bay.

The Almanac/Barbara Wood, 10/16/14.  "First water from new Bay Tunnel reaches Crystal Springs."

system map
Water supply route Hetch Hetchy to Crystal Springs
Eighty years ago, the arrival of the first drinking water to make the long journey from the Hetch Hetchy reservoir in the Sierra Nevada to Crystal Springs Reservoir was greeted at the site of the Pulgas Water Temple off Canada Road north of Woodside by a crowd estimated at 20,000 people.

On Wednesday (Oct. 15) a much smaller group met in the same place to greet the arrival of the first drinking water to travel from Hetch Hetchy to Crystal Springs via a newly completed Bay Tunnel, which goes under the San Francisco Bay.  The new tunnel should make the water supply for the Peninsula and San Francisco much more likely to be available after a major earthquake, officials say.

.... "San Mateo County has been pivotal to the water supply of San Francisco going back to 1852," when the first water storage reservoir was built here, he said. Today, as scientists warn that another major earthquake could be imminent, the system is ready, he said, "This work was done ahead of "a possible disaster, he said.   

....  The Bay Tunnel is just one part of the Hetch Hetchy Water System Improvement Program, with a $4.6 billion budget, primarily designed to assure water will still be available after an earthquake. The project also will develop new sources of groundwater and a supply of recycled water.    Read article.

Related article with video - ABC 7 news/Katie Marzullo, 10/15/14. "Hetch Hetchy delivers seismically sound water tunnel." This tunnel is one of the most significant projects, of the 83 projects on tap. Officials had two choices -- replace the aging, leaking pipes that run along the Dumbarton Bridge or bore a tunnel under the San Francisco Bay. We decided the tunnel because the tunnel was more seismically resistant and also it minimized the impact of sensitive habitat and wildlife that was on the surface," said Harlan Kelly, General Manager of the San Francisco Public Utilities Commission. The tunnel is five miles long, under the San Francisco Bay and it's the first of its kind. Not to be confused with the Transbay Tube, which sits on the bay floor."

Reference San Francisco Water Power Sewer,"services of the San Francisco Public Utilities Commission". "We manage a complex water supply system stretching from the Sierra to the City and featuring a complex series of reservoirs, tunnels, pipelines, and treatment systems.  ...The Peninsula watershed in San Mateo County contributes surface water supplies captured and stored in lower and upper Crystal Springs and San Andreas Reservoirs and in two smaller reservoirs, Pilarcitos and Stone Dam. The 6 reservoirs in the Alameda and Peninsula watersheds capture rain and local runoff.

Note the graphic water system map is from this San Francisco Water Power Sewer (reference above). The map details are fuzzy, for better detail you may want to open that link.   

Posted by Kathy Meeh

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