Another warning of Sacramento delta crisis

California has to change the way it manages the hub of its vast water system or face economic and environmental disaster in the Sacramento-San Joaquin Delta, warns a report released Wednesday by the Public Policy Institute of California.

The book-length document, written by a group of UC Davis experts and institute research fellow Ellen Hanak, adds to a growing consensus that the status quo in the delta, which provides two out of three Californians with fresh water, is unsustainable.

“The delta is facing a crisis that will affect all Californians,” said Hanak, whose organization is a private nonprofit that conducts independent research on major policy issues in the state.

While stopping short of recommending one solution, the authors say several controversial options should be investigated, including reducing water exports and piping water supplies around the delta in a smaller version of the peripheral canal that was rejected by voters in the 1980s.

Part of the largest estuary on the West Coast, the delta east of San Francisco is the center of water shipments from the state’s wet north to its arid Central Valley and urban Southern California, playing a vital role in California’s economy. It also has hundreds of thousands of acres of cropland and a network of utility lines and roads.

But it faces a mounting list of problems despite a decade-long government attempt to improve its environment and water deliveries.

The delta’s lengthy levee system could collapse in a major earthquake. Rising sea levels caused by global warming coupled with the continued subsidence of its farming islands increase the risk of flooding that would contaminate fresh water supplies with ocean flows.

Housing developments are rising on its edge. Fish populations, including that of the native delta smelt, have collapsed in recent years. Invasive species are altering the delta’s basic food systems.

Moreover, CalFed, the state-federal program created to fix the ailing delta, has foundered amid a shortage of funding and criticism that it tried to please everybody.

The public policy report is not so politic. “There’s something in that package to make everyone nervous,” Barry Nelson, a senior policy analyst with the Natural Resources Defense Council, said after a briefing on the document.

Saying that the situation is not hopeless, the report lays out a handful of alternatives for doing things differently in the delta while rejecting other options.

Generally, the authors say, efforts to keep delta waters consistently fresh to protect water deliveries to the south as well as irrigation supplies in the delta have hurt native species and aided alien species. It would be better, they say, to allow more natural variability in salinity levels, which historically advanced and retreated with seasonal changes in river and bay flows.

One way of achieving that, they say, would be to build an aqueduct, or peripheral canal, to take water from the Sacramento River north of the delta and carry it around the delta to the big federal and state pumps in the south delta that send water to the San Joaquin Valley and Southern California.

A variation of that approach would be to pipe water from the Sacramento to the lower reaches of the San Joaquin River, which flows into the southern delta. An in-delta channel for freshwater could also be created by building up some central delta islands and installing tide gates.

“I tend to think a peripheral canal gives you an opportunity to re-plumb the system and make it more fish-friendly,” said one of the report’s authors, UC Davis engineering professor Jay R. Lund.

The authors said they are talking about a smaller version of the canal project that was defeated by voters two decades ago amid concerns that it would send more water south and hurt the environment.

Still, concerns remain that large diversions from the Sacramento River above the delta could harm migrating salmon and lower delta water quality.

Other options outlined in the report could also prove controversial.

Under one alternative, seasonal water exports from the delta would be allowed only during times of high river flows in the winter and spring. In another scheme, uses of the delta, including water exports, would only be permitted to the extent that they did not interfere with delta restoration.

At the same time, the report said it would be unacceptable to completely abandon the delta for farming or as a water source. Conversely, they rejected the idea of fortifying the delta levee system at all cost to maintain current uses.

The 285-page document, “Envisioning Futures for the Sacramento-San Joaquin Delta,” was released the same day Gov. Arnold Schwarzenegger named his appointments to a blue ribbon task force that will spend the next two years developing management recommendations for the delta.

“I think that [the report] is going to be a major contribution to the discussion of the delta,” said Kamyar Guivetchi, Department of Water Resources planning manager.

bettina.boxall@latimes.com