‘Next New Orleans’ may be in California

Alan Boyle Science editor • Profile • E-mail

ST. LOUIS - Years before Hurricane Katrina hit, engineers knew that New Orleans was the most vulnerable spot in the country for flood damage — and some even predicted almost exactly how the tragedy would unfold.

Now the experts say California's Sacramento-San Joaquin Delta presents the next cause for concern. "The Sacramento area is perhaps, after New Orleans, the scariest spot in the country," said Nicholas Pinter, a geologist at Southern Illinois University who studies river flood risks.

The subject of future risks — and what to do about flood-prone regions ranging from Louisiana to California — was a subject of debate Saturday at the annual meeting of the American Association for the Advancement of Science. Even St. Louis, the site of this year's meeting, was considered a region at risk.

A panel of experts held out little hope that the risks would be eased, however, unless governments on all levels took a harder look at the standards for levee construction and changed policies that actually encouraged development in vulnerable areas.

It's difficult for the lessons from past floods to sink in, even when it's a flood as catastrophic as the one caused by Katrina, said the University of Maryland's Gerald Galloway, a former brigadier general in the U.S. Army Corps of Engineers.

"The half-life of the memory of a flood is very short," he told reporters. "You can already hear it in Washington D.C. ... 'New Orleans, where?'"

California delta at risk
Unlike New Orleans, the delta at the confluence of California's Sacramento and San Joaquin rivers is about 80 miles inland — and thousands of miles from the nation's hurricane zone. But like New Orleans, the delta's historic floodplains are protected by an extensive and expensive system of levees and dams. Much of Sacramento itself sits lower than the levees protecting the city.

Last fall, The Sacramento Bee reported that more than 300,000 people would be in the direct path of a flood.

The chances of a catastrophic flood occurring in the Sacramento-San Joaquin Delta sometime in the next 50 years are about two out of three, said Jeffrey Mount, director of the Center for Integrated Watershed Science and Management at the University of California at Davis.

"It is the most at-risk large metropolitan area in the country, with less than half the protection" that New Orleans had, Mount said. "It is at extreme risk due to levee failure and subsidence."

St. Louis blues
Hundreds of miles upstream from New Orleans, the increasingly corseted Mississippi River also holds the potential for catastrophic flooding, the experts said. Pinter noted that along some stretches of the river around St. Louis, flood levels are up to 12 feet (3.7 meters) higher than they were in 1900.

Pinter referred to the Great Midwest Flood of 1993, which caused an estimated $15 billion in damage. Since then, there has been $2.2 billion worth of new construction on land that was underwater in 1993, he said. New levees have been built, but in Katrina's wake, the experts said those levees may be inadequate.

In some of the historically flood-prone areas around St. Louis, "the possibility of seeing a mini-New Orleans situation here is definitely an issue," said Adolphus Busch IV, a member of St. Louis' Anheuser-Busch beer-brewing family.

Busch is working to cut back on the pace of floodplain development as chairman of the Great Rivers Habitat Alliance. The alliance has filed lawsuits in an effort to block tax incentives for development of lands that may be flooded if levees break.

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