[Water_news] 1. DWR'S CALIFORNIA WATER NEWS - Top Item for 4/20/08

Department of Water Resources

California Water News

A daily compilation for DWR personnel of significant news articles and comment

 

April 21, 2008

 

1.  Top Item -

 

 

Delta panel tries to prepare for sea-level rise

Sacramento Bee – 4/20/08

By Matt Weiser, staff writer

 

Global warming could put the Sacramento-San Joaquin Delta under much deeper water than previously estimated.

 

A panel appointed by Gov. Arnold Schwarzenegger is urging him to prepare for a sea level rise of 55 inches in the Delta by the end of this century. That's a lot more water than any estimates currently in use by the state.

 

The Delta Vision Blue Ribbon Task Force, in fact, found during its research that many state agencies still have no target number at all to plan for sea level rise. That includes Caltrans, which is planning to widen Highway 12, a cross-Delta route between Lodi and Fairfield that already lies 20 feet below sea level in places.

A sea level increase of 55 inches, or about 1.4 meters, would probably overwhelm most levees in the Delta.

 

It would also likely flood thousands of acres of low-lying urban land surrounding the Delta, including some neighborhoods, urban water intakes, sewage treatment outfalls, highways and other utilities.

 

"The problem is, this is a high-risk area," said Phil Isenberg, Delta Vision chairman and a former Sacramento mayor and state assemblyman.

 

"We ought to have a common planning assumption for state agencies. Because the more rise you predict, well, the more complicated life becomes in the future."

The Delta is particularly vulnerable to sea level rise because its towns, farms and infrastructure sit on islands. Many islands have sunk well below sea level due to the loss of peat soils over the past century. They now depend on fragile levees to stay dry.

 

Scientists advising the Delta Vision panel reported in September that officials should prepare for a sea level rise of 39 inches by 2100. That number was double most estimates in use then.

 

The task force took that advice and went further in its March 28 letter to the governor.

 

Citing uncertainty in the projections – and the likelihood that seas will rise more, not less – the panel urged the governor to direct all state agencies to prepare for 16 inches of sea level rise by 2050 and 55 inches by 2100.

 

"I think that's the high range, but certainly plausible," said Jeffrey Mount, a UC Davis geology professor and chairman of a science panel that advises Delta Vision. "From a planning perspective, that's building in a factor of safety, and that's probably a good thing."

 

Delta Vision also sent a letter April 9 to Caltrans Director Will Kempton, asking him to explain whether the plan for Highway 12 accounts for sea level rise.

The chief uncertainty in predicting sea level is the melting of ice caps on polar continents. This is already occurring, particularly on Greenland, and is expected to accelerate.

 

But none of the current models used by climate scientists can account for this melting. This means most estimates of sea level rise are probably low.

 

A major flood in the Delta – whether caused by global warming, storms or an earthquake – would affect the entire state. Water intakes in the south Delta that serve 25 million people in the Bay Area and Southern California would become contaminated with salt water, putting them out of commission, perhaps permanently.

Delta Vision is charged with proposing solutions to such threats. Its initial report outlining the problems was presented in December, with final recommendations coming in October.

 

Solutions, from building a new water canal to strengthening levees, will cost many billions of dollars. Without accurate sea-level predictions, that money could be wasted.

 

In its report to the governor, the task force surveyed 23 state and federal agencies to learn their sea-level predictions. Only two, both closely associated with the task force itself, have considered a potential rise of 55 inches. Those are the CalFed Bay-Delta Program and the Delta Risk Management Strategy, a research effort by the Department of Water Resources.

 

Other estimates for 2100 fall between 28 and 35 inches. But 11 agencies have no estimate to guide their work, Delta Vision found, including Caltrans, the U.S. Army Corps of Engineers and Bureau of Reclamation, the state Public Utilities Commission and Water Resources Control Board.

 

The task force urged Schwarzenegger to issue an executive order requiring all state agencies to adopt the 55-inch estimate as a planning target, and not just for the Delta but all regions of the state. It also asked him to set a schedule to review this estimate for accuracy on a regular basis.

Lisa Page, a spokeswoman for Schwarzenegger, said the Governor's Office is still reviewing the recommendation.#

http://www.sacbee.com/101/story/875723.html