State and federal leaders on Wednesday reaffirmed their commitment to build a giant pair of tunnels to divert the Sacramento River out of the Delta.

Gov. Jerry Brown and U.S. Interior Secretary Ken Salazar said at a news conference in Sacramento they believe the tunnel plan is crucial to solve conflicting problems that have long divided the state: protecting the fragile environment of the Sacramento-San Joaquin Delta and also safeguarding freshwater diversions in the estuary from earthquakes, sea level rise and levee failures.

"This is all about California's future," Brown said. "I see this as another test of whether we can govern ourselves."

The details of the proposal they discussed are not new. It calls for two massive tunnels large enough to divert the Sacramento River at 9,000 cubic feet per second from three intakes somewhere between Freeport and Courtland. The intent is to end the reverse flows caused by current state and federal pumps in the south Delta, which alter aquatic habitat and kill millions of fish.

The estimated cost of the plumbing is about $14 billion, to be funded by some three dozen water agencies from San Jose to San Diego, which rely on Delta water to serve 23 million Californians and 3 million acres of farmland.

What is new is the federal government's commitment to the project. In recent years as the project was planned, Interior Department leaders have been careful to say they will await the outcome of concise environmental studies before deciding whether to support the project. That changed on Wednesday.

"It's a real blueprint and we are committed to moving it across the finish line," said Salazar. "We know this is not a perfect answer. We know everyone is not going to agree with this particular answer. But we know we are closer than ever to a sustainable solution."

The Interior Department oversees both the U.S. Bureau of Reclamation, which operates one of two large water diversion systems in the Delta, and the U.S. Fish and Wildlife Service, charged with restoring native freshwater fish including the imperiled Delta smelt.

Also expressing support for the project Wednesday was the National Marine Fisheries Service, charged with restoring salmon and sturgeon species imperiled by Delta water diversions.

In April, the fisheries service is one of several agencies which drafted "red flag memos" critical of an earlier proposal that had a larger capacity of 15,000 cfs and five intakes.

Will Stelle, West Coast salmon coordinator at the fisheries service, said the smaller project is a direct result of those red flag memos.

"Do we think these changes are going to work? We believe yes," Stelle said.

Planning for the tunnels is being led by the California Natural Resources Agency, which oversees both the Department of Water Resources and Fish and Game. The agency expects to release an environmental study on the project for public review this fall. If approved, it would take at least a decade to construct.

Environmental groups and local politicians continue to stand firm against the project, arguing that simply moving the diversion works upstream won't solve the Delta's problems and may create new ones.

"This proposal is fatally flawed," Barbara Barrigan-Parrilla, executive director of Restore the Delta, said in a statement. "We oppose the rush to build a project that would exterminate salmon runs, destroy sustainable family farms and saddle taxpayers with tens of billion of dollars in debt."

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