ANTIOCH (CBS SF) -- Construction on a $30 million emergency barrier to prevent salt water from entering drinking water supplies began this week in the Sacramento-San Joaquin River Delta, state water officials said Friday.
The temporary barrier at West False River will take several weeks to install and will be removed in mid-November to avoid the flood season and allow migrating fish to travel through the area, officials from the state Department of Water Resources said.
The barrier, which is essentially a 750-foot-long pile of rocks, will help maintain fresh water in the delta and prevent salt water from contaminating the region's drinking and agricultural water supplies, DWR officials said.
The Contra Costa Water District has four water intakes in the delta and relies on the delta for its drinking water, according to district spokeswoman Jennifer Allen.
Residents in Alameda and Santa Clara counties also rely on some of the water that comes from the delta, state officials said.
DWR spokesman Doug Carlson said the last of the necessary permits for the project was received on Monday and preliminary construction began Tuesday.
DWR is consulting with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service to ensure that protections are in place for delta smelt, Chinook salmon and other species, according to state officials.
Boats will be unable to pass through West False River after the barrier is installed, officials said.
DWR director Mark Cowin called the barrier an "undesirable but necessary" tool to conserve fresh water.
"With 2015 turning out to be warmer and drier than normal, water conservation is crucially important," Cowin said in a statement. "California's four-year drought is one of the worst in our recorded history."
State officials estimated that the design, installation, monitoring and mitigation of the barrier will cost $22 million and removal of the barrier is estimated to cost another $18 million, Carlson said.
The project is being paid for with a combination of funding from Proposition 50, a $3.4 billion water bond approved by voters in 2002, and money from the state's general fund.
It's not the first time a rock barrier has been installed to protect against salt water intrusion. Carlson said a similar barrier was built during the statewide drought of 1976-1977.
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