SACRAMENTO (CBS SF) — California and federal officials have announced plans for a massive twin tunnel system to carry water from the Sacramento-San Joaquin River Delta to Southern California farmland and cities.

Gov. Jerry Brown and Interior Secretary Ken Salazar unveiled the proposal at a Sacramento press conference on Wednesday.

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The governor and the Interior Department propose construction of a $23 billion, 37-mile long series of tunnels that would be buried underneath the delta. It would divert water into canals that feed much of the state.

Supporters said the tunnels would guarantee a stable water supply for Californians. But opponents argue the project could destroy the already fragile delta ecosystem.

Victor Gonella, president of the Golden Gate Salmon Association, said his fear is that the conveyance could adversely impact salmon runs.

KCBS’ Dave Padilla Reports:

“There is enough water in the system right now if we all just do a little bit better job of when we pump water south and when we don’t pump water south,” said Gonella.

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The Contra Costa Water District supplies 500,000 customers with water from the Delta. CCWD Assistant General Manager Greg Gartrell said his main concern is that salinity levels will increase, affecting the quality of water for customers.

“It’s essentially saying, we’re going to have a big impact on you and you go figure out how to mitigate that yourself,” Gartrell said. “And that’s simply wrong.”

Gartrell said that the newly expanded Los Vaqueros Reservoir would be used to reduce the salt content of Delta water should the state send water to Southern California.

The federal-state Bay Delta Conservation Plan, which would involve two huge 33-foot wide tunnels, would allow freshwater to flow from the Bay Area to San Diego, allowing for the irrigation of 3 million acres of farmland.

Construction is scheduled to start in 2017 and the project is expected to be completed by 2026.

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