SACRAMENTO — A giant tunnel, and not a canal, has emerged as the leading option to ship Sacramento River water across the delta to thirsty Californians from Silicon Valley to San Diego.
Officials guiding the Bay Delta Conservation Plan chose the tunnel for more detailed study at a meeting Thursday in Sacramento. The plan is an effort to secure California water supplies from environmental problems, flood risk and rising sea levels in the Sacramento-San Joaquin Delta.
About 25 million Californians and 2 million acres of farmland depend on the delta for at least some of their water supply.
The decision Thursday only targets the tunnel for more detailed study. It was not a decision to build a tunnel or to exclude other options.
The tunnel would be 43 miles long. Over most of that length, there would be not one but two parallel tunnels about 150 feet underground, each 33 feet in diameter.
The tunnels would rank among the largest of their kind in the world. Multiple tunneling machines would work simultaneously for about eight years, consuming $284 million worth of electricity.
The tunnels could move water at 15,000 cubic feet per second, or 10 times the volume in the Tuolumne River. Estimated cost: up to $11.6 billion.
Water agencies that would benefit, notably those serving San Joaquin Valley farmers and the Metropolitan Water District of Southern California, have agreed to pay for it. The cost would be passed on to ratepayers.
"I believe it is a milestone that we just arrived at," said Karen Scarborough, undersecretary of California's Natural Resources Agency, who leads the group's steering committee. "It's a major thing that we just did."
Participating environmental groups supported further study of the tunnel but have not agreed to support its construction.
Their involvement was shaken Thursday by news that U.S. Sen. Dianne Feinstein plans to amend a jobs bill to alter delta fish protections. It would guarantee San Joaquin Valley farmers 40 percent of their contract water deliveries for two years. Currently, farmers south of the delta are scheduled to receive only 10 percent of their allocation.
"I believe we need a fair compromise that will respect the Endangered Species Act while recognizing the fact that people in California's breadbasket face complete economic ruin without help," Feinstein said.
'Playing it both ways'
Such diversions could harm threatened salmon and delta smelt. Andrew Fahlund, American Rivers senior vice president, warned that increasing water pumping to valley farms "could be the end of the West Coast salmon fishery."
Ann Hayden, a senior water analyst at the Environmental Defense Fund, said her group would quit the conservation planning process if the Feinstein amendment passes.
She called it an act of betrayal, since some water interests on the committee undoubtedly asked Feinstein for the amendment.
"It doesn't help to know that folks we're partnering with are playing it both ways," Hayden said. "It will make the long-term planning almost meaningless if, in the short-term, actions are taken that push some species to the point of extinction."
With or without environmental partners, the conservation plan is far from finished.
A draft environmental study is not expected until year's end. It then must be approved by wildlife agencies to satisfy the Endangered Species Act.
It also hinges on politics. The Schwarzenegger administration supports the plan and believes it has legal authority to build a canal or tunnel.
But a new governor will be in charge by the time a decision must be made. The Legislature also could influence the outcome.
Present estimates are that construction would start in 2013 and finish in 2022.
Some view the tunnel favorably because it minimizes environmental harm on the surface, as well as the amount of land that must be acquired.
That is significant because most delta residents oppose the project and could mount fierce resistance. The state Department of Water Resources is fighting more than 120 lawsuits with delta property owners who refuse access for preliminary surveys.
"In our minds, it probably is a better place to land long term than the canal," said Department of Water Resources Deputy Director Jerry Johns.
The tunnel comes with greater construction risk, largely because the structure of soils 150 feet beneath the delta is not well-known.
Tunneling of the sort required for the project is easier in solid rock than in loose material, because of threats of collapse and flooding.
Ken Verosub, a University of California at Davis geology professor, said there is no solid material beneath the delta. It is probably layers of loose material deposited as the delta shrank and expanded with repeated glacial periods.
"There are older delta sediments — peats and organics and sands — down several hundred feet at least," said Roy Shlemon, a consulting geologist in Newport Beach who has studied the delta.