California Practices for Flooding as South is Inundated

By DON THOMPSON | May 19, 2011

Emergency workers in nearly half of California counties will be practicing for a catastrophic flood this week – a drill given added urgency by the once-in-a-generation flooding in the Mississippi River delta 2,300 miles to the east.

The reason for the drill is clear: Similar devastation has struck before, and federal officials have determined that California’s capital has the highest flood risk of any U.S. city outside New Orleans.

“We’ve got the potential for a mass evacuation if the worst conditions present themselves,” said Mike Dayton, acting secretary of the California Emergency Management Agency.

Residents need only turn on their televisions to see the sort of disruption and devastation that could occur on just a few days’ notice, he said. If conditions are just right, even the state’s complex system of dams, flood gates and overflow areas might not be able to contain flood waters.

More than 1,100 miles of levees built more than a century ago to create farmland in the Sacramento River delta are vulnerable to collapse, endangering the water supply for 25 million people in central and southern California. Emergency officials say more than half the state’s nearly 39 million people rely on levees and flood-control reservoirs for protection, a system that could be strained past the breaking point in a catastrophic flood.

The certainty that massive flooding is one day inevitable in California’s Central Valley is the premise behind this week’s emergency drill.

The three-day exercise that begins Tuesday will include mock evacuations, sandbagging of a delta island, and the mobilization of emergency operations in 23 of the state’s 58 counties, from Bakersfield to Redding.

It follows last year’s drill that emergency officials say was the nation’s largest exercise anticipating terrorist attacks on the state’s ports.

This year’s drill includes 22 state and 12 federal agencies, along with the American Red Cross and Salvation Army. Twenty-seven hospitals plan to practice for surges in patients and the possibility they might need to evacuate. Planners expect more than 5,000 participants in 10 cities, second only to the roughly 10,000 that joined a 2008 drill focusing on a massive Southern California earthquake.

The scenario this year starts with conditions that existed for real just two months ago, when near-constant storms piled up Sierra Nevada snow and brought rivers near flood stage as water managers drained reservoirs as fast as they could.

Then it adds what is known as a “pineapple express,” a warm, heavy storm system that originates near the Hawaiian Islands and heads east with a fire hose of precipitation.

Something similar happened for real in January 1997, when a warm deluge rapidly melted a deep snowpack. As much as 24 inches of precipitation fell within days, causing flooding and disaster declarations in 43 California counties, according to the U.S. Geological Survey.

This week’s exercise assumes that hospitals would see a surge of patients, while major Central Valley highways as well as many local roads would be under water. Numerous levees would fail, while high winds, power outages and mudslides would make response more difficult. Low-lying areas would be flooded in several communities.

And that’s only Day One, Tuesday, under this week’s game.

Day Two brings the assumption of flooding in some cities, while others would be cut off by rising water. Hospitals could be inundated by high water, as well as patients. Levees protecting several Sacramento-area communities could fail. Two or more delta islands could flood, sucking in salty ocean water and endangering the state’s water supply.

By Day Three, Fresno and Merced would be among the many Central Valley cities with flood problems. Prisons in Corcoran and Coalinga might have to start evacuating, prompting the California Department of Corrections and Rehabilitation to consider what it would take to move, securely house and feed more than 6,000 inmates.

If it happened for real, Dayton said there would be pockets where residents would be entirely on their own for at least three days until the first official help could arrive.

Officials said California could one day face the same sort of decision the Army Corps of Engineers made this weekend when it began opening Louisiana’s Morganza Spillway to protect New Orleans and Baton Rouge, while flooding miles of more rural property.

But jurisdictions overlap between federal, state, local and private water managers and flood protection districts in California, forming what Dayton said is perhaps the nation’s most complex flood and water management system.

“Do we blow the levee or don’t we blow the levee?” asked James Woodward, who is planning the exercise for the emergency management agency. “Somebody has to make that decision and has to own it.”

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