Delta canal fears raised

Though old enemies may be looking afresh at a peripheral canal to divert water around the Sacramento-San Joaquin Delta, a panel of scientists warned Wednesday that no one knows how such a canal will affect the sensitive estuary.

Gov. Arnold Schwarzegger has mounted a campaign to build the canal. Rejected by state voters in 1982, the project is getting renewed focus as a fix for the Delta, where water quality is suffering and fish are in decline as the estuary strains to provide water to two out of three Californians.

The original proposal called for a 43-mile canal to divert Sacramento River water near the town of Hood, and carry it around the Delta directly to state and federal export pumps near Tracy. It was thought this would isolate exports from Delta water quality problems, while preventing fish from being killed in export pumps.

Critics opposed the original project because they feared it was a tool for Southern California to grab more north state water.

Now, a generation later, the Delta is widely considered to be in crisis, partly because water exports near Tracy continue to kill fish, including Delta smelt, green sturgeon, striped bass and chinook salmon.

Also, new research warns that an earthquake could devastate Delta levees, causing a statewide water and economic disaster.

Schwarzenegger carefully avoids the term "peripheral canal," which still conjures one of California's biggest water wars. But even some environmental groups are open to the notion that a canal in some form might improve conditions.

"We have studied this subject to death. It's time for action," Schwarzenegger said in a June speech.

But a panel of scientists said Wednesday that we still know almost nothing about how a peripheral canal would affect fish and water quality in the Delta.

William Bennett, a UC Davis fisheries biologist, said diverting water from the Sacramento River at Hood could harm rather than help Delta smelt. The population of the tiny fish plunged this year and forced a nine-day shutdown of the state's Delta export pumps.

River channels and sloughs downstream from Hood were only recently identified as a key breeding ground for smelt. A major new upstream diversion, he said, could reverse the river's flow in drought years, killing smelt and altering water quality just as the current pumps do now in the south Delta.

"The peripheral canal has been touted widely as solving all the Delta smelt's problems. I don't think that's really true," said Bennett, who spoke at a science workshop on the canal convened by the CalFed Bay-Delta Program. "It's quite likely, if we're not careful about how we operate this, that impacts to Delta smelt could actually be larger than they are now."

Dennis Majors, engineering program manager at the Metropolitan Water District of Southern California, the largest urban user of Delta water, said the peripheral canal may not be immune to major floods. That's because, as currently envisioned in most scenarios, it would lie below sea level in its southern reach between the San Joaquin River and the export pumps.

He said most canal proposals consist of an open ditch.

"If you have levee breaks down there, it will just flow right in (to the canal) real nicely by gravity," said Majors, who is also a committee member for the Delta Risk Management Strategy, an effort by the state Department of Water Resources to propose sustainable alternatives for the Delta's future.

The solution is to build levees along the canal, which adds cost. The export water could also be confined instead to an elevated pipeline, but that is likely to be much more expensive and could require two or more pipes to equal the capacity of a canal.

Sam Luoma, research hydrologist at the U.S. Geological Survey, said that by diverting Sacramento River water around the Delta, dirtier waters of the San Joaquin River become a bigger problem in the estuary.

Compared to the Sacramento, the San Joaquin is five times saltier and carries as much as 85 times more selenium, a natural element that causes wildlife deformities when concentrated by farm runoff. Fixing water quality must come before a canal, he said.

"If we're talking about higher quality water for (export) users, it's going to come at a cost of lower quality water for the Delta and the Bay," Luoma said. "We have to analyze these things and we have to study them as we go along."

These comments echoed those of Jeffrey Mount, a UC Davis geology professor who co-authored a 2004 study that first illustrated earthquake risks in the Delta. He spoke Tuesday at a "Delta Summit" hosted in Los Angeles by Schwarzenegger and U.S. Sen. Dianne Feinstein, D-San Francisco.

The senator, a foe of the 1982 canal, said she now intends to "look at the situation fresh," and pressed Mount to name a "best alternative" for routing water around the Delta.

"I can't tell you because we haven't done the science on that," Mount said. "I'm not just being a weasel to get out of having to answer your question. I'm telling you the honest truth: We haven't done that work yet."

Jerry Johns, DWR deputy director, said at Wednesday's workshop that he understands the uncertainties. But he said the goal of the administration's Delta investigations is to reach broad agreement on the available science, while moving ahead with a fix adaptable to new information.

That might include, he said, a peripheral canal built with a small intake so diversions are strictly limited.

If it proves effective, the intake could be enlarged later. Carefully crafted operating rules could also allay many concerns, he said.

"This is truly a societal issue we've got to face, and we've got to understand the science to make sure we're heading in the right direction," Johns said. "We don't know a whole lot now, but we certainly know better now."

About the writer:

• The Bee's Matt Weiser can be reached at (916) 321-1264 or mweiser@sacbee.com.