An Introduction to California's Delta Tunnel and Salmon Controversy

A plan to build two tunnels that would divert water from Sacramento to San Joaquin Valley farms poses a dire threat to salmon, according to a Bay Area salmon protection group.

The tunnels are the linchpin of the Bay Delta Conservation Plan (BDCP), a draft of the environmental impact assessment for which was released Tuesday by the California Department of Water Resources (DWR).

DWR is working, along with federal agencies and local water districts, to change the way California diverts Sacramento River water past its natural outflow through the San Francisco Bay to thirsty industrial farms and Southern California cities. And the result, which some are calling a rehash of Governor Jerry Brown's 1980s-era Peripheral Canal proposal, is raising hackles among environmentalists -- including one group concerned that the project could doom California salmon.

The plan's Draft Environmental Impact Report/Environmental Impact Statement (DEIR/EIS) is as formidable as that name might imply -- it's more than 34,000 pages. The Executive Summary alone is 132 pages long. But it doesn't take long to describe the tunnels. Running thirty-five miles long from Freeport to Tracy, each tunnel 40 feet wide, built at a cost of up to $69 billion, the tunnels could conceivably carry the whole flow of the Sacramento River during the dry season.

The intent of the tunnels, as was the case with the 30-year-old Peripheral Canal proposal, is to divert Sacramento River water for shipment south before it reaches the Sacramento Delta. At present, water is pumped to the San Joaquin Valley from the Delta itself, which can have marked effects on how water flows through the state's largest wetlands. Water naturally flows through the Delta from east to west, as snowmelt and runoff from the Sierra Nevada and Cascade mountains flow down the Sacramento and San Joaquin rivers and out to sea.

But the State Water Project and Central Valley Project operate powerful intake pumps at the south end of the Delta, and those pumps cause the Delta's water to flow north to south rather than east to west. That has allowed salt water from the Bay to penetrate farther inland, threatening the welfare of a number of wildlife species. Most notable is the Delta smelt: evolved over millennia to tolerate a narrow range of salinity, the smelt has lost most of its habitat due to water diversions from the Delta.

In theory, diverting water before it reaches the Delta could help restore historic flow patterns through the Delta, lessening the impact on species like the Delta smelt. But the sheer volume of water the tunnels would be capable of diverting could well erase that putative benefit, says the Golden Gate Salmon Association's (GGSA) John McManus -- especially with regard to the survival of the Sacramento River's beleaguered salmon runs.

"Two giant pipes and diversions big enough to dry up the entire Sacramento River at most times of the year can't be good for salmon," says McManus (who, in the interests of full disclosure, is my former co-worker). "In addition, the state's own analysis shows the tunnel and diversions could literally cook young salmon by causing upstream river temperatures to rise to lethal levels."

"Diversion of too much Sacramento River water in the years 2000 to 2006 devastated the salmon fishery and forced the first closure of the ocean to salmon fishing in 2008 and 2009," adds GGSA founder Victor Gonella. "The project proposed today would likely lead to the same or worse consequences to the salmon fishery."

It's not just salmon at risk, according to some critics of the plan.

The BDCP is intended to function as both a Habitat Conservation Plan under the federal Endangered Species Act and a Natural Community Conservation Plan under California law to protect 56 species of concern, ranging from the Delta smelt and the Sacramento River's salmon runs to the Valley elderberry longhorned beetle.

But the plan's benefit to those species is open to question. The BDCP would operate with what's familiarly called a "no surprises" assurance, described by the USFWS thusly:

Those assurances for each of the 56 species covered by the BDCP would be good for 50 years: half a century of potential ecological change during which the tunnels' operators wouldn't need to adjust their policies except by any terms agreed to at the outset, even if wildlife populations crashed around them.

You might reasonably compare the BDCP to the Desert Renewable Energy and Conservation Plan as an example of what happens when the government yokes Habitat Conservation Plans to economic development plans. The DRECP is supposed to promote desert conservation and renewable energy development at the same time, just as the BDCP theoretically promotes both conservation and more efficient transfer of water from northern watersheds to southern farms and cities.

The question is whether those implementing the plans can really give equal priority to each of the plans' dual aims.

The BDCP promises to be a major, contentious, and litigated environmental issue in the next few months, and we'll be watching -- and trying to get through 34,000 pages of draft environmental assessment. In the meantime, at least one species' defenders have weighed in.

"The state committed itself a few years ago to rebuilding Central Valley salmon runs to 990,000 naturally spawning fish," says GGSA board member Zeke Grader, who's also executive director of the Pacific Coast Federation of Fishermen's Associations. "The gigantic, hugely expensive, peripheral tunnels project being proposed is an abandonment of this commitment. While some elected officials are bending over backwards to help a small group of corporate growers, they're ignoring the huge value salmon bring to the state."