California urges tunnel system for delta

State officials Wednesday recommended construction of a $13-billion tunnel system that would carry water under the troubled Sacramento-San Joaquin River Delta to southbound aqueducts, a project that would replumb a perpetual bottleneck in California’s vast water delivery network.

The proposal is far from final. It faces a new administration, lengthy environmental reviews and controversy over how much water should be exported from the Northern California estuary system that serves as a conduit for water shipments to Southern California and the San Joaquin Valley. The earliest completion date would be 2022.

The tunnel plan is a variation of an idea that has been around for decades. Voters in 1982 killed a proposal to route water around the delta in a canal. But talk of a bypass has resurfaced as endangered species protections in recent years have forced cutbacks in pumping from the south delta.

Some water would still be pumped from the south under the new proposal, but the bulk would be drawn from the Sacramento River as it enters the north delta. The water would then be carried by two huge tunnels, 150 feet deep, to the federal and state aqueducts.

Some delta advocates remain staunchly opposed to the concept. But there is growing agreement that changing diversion points could lessen the environmental impacts of pumping and that a tunnel would not be as vulnerable to earthquake damage as a canal bypass or the existing pumping operations.

The project, which would be accompanied by $3.3-billion worth of habitat restoration over 50 years, is part of an ambitious multi-agency program intended to resolve the conflict that has enveloped the delta for decades.

Reaction to the state recommendations, which the Obama administration generally endorsed, underscored how difficult it may be to achieve a delta truce. Environmental groups assailed the planning report as “flawed, incomplete and disappointing.” And the largest irrigation district in California already pulled its support of the plan, suspecting that it would not restore its water supplies.

Of particular contention to environmentalists are the size of the tunnel system and the operating rules that would determine the volume of diversions.

California Natural Resources Secretary Lester Snow said Wednesday that annual delta exports under the project could average 5.4 to 5.9 million acre-feet, more than allowed under current environmental restrictions — and considerably more than environmentalists and some fish biologists say the delta ecosystem can withstand if it is to make any sort of recovery.

Critics said there were too many unsettled issues to make such a projection, and they accused federal and state officials of pandering to the agricultural and urban water agencies that would pay for the tunnel system.

Officials “know the assertions that they’re making aren’t true,” said Gary Bobker of the Bay Institute, one of the environmental groups participating in the delta program. “They know that the amount of water that we’re going to be able to export from the delta in the future is probably not going to be the kind of numbers the [plan] is talking about.”

Last month, the giant Westlands Water District said it was pulling out of the delta program because it didn’t think the project would live up to its promise of restoring delta exports, which had reached record levels before the recent drought and endangered species cutbacks of the last two years.

“We cannot justify the expenditure of billions of dollars for a program that is unlikely to restore our water supply,” Westlands General Manager Tom Birmingham said Wednesday.

He added that the state plans and statements by the U.S. Interior Department that the project could increase deliveries were a good sign.

“What Interior said today is encouraging. But whether Westlands reverses its position or decision is going to be determined by what Interior does, as opposed to what it says.”

bettina.boxall@latimes.com