Officials Step Up Planning for Possible Green River Flooding

09/15/2009

King County Executive Kurt Triplett says he will ask the County Council for more than $40 million to prepare for the possibility of severe flooding in the Green River Valley. The money would be used to shore up the river's levee system, and to move critical county services to higher ground.

Officials are concerned about the stability of the Howard Hanson Dam, which was built almost a half century ago to control flooding on the often flooded Green River. Last winter, the Army Corps of Engineers noticed two depressions in the rock wall at one end of the dam. Heavy rains had apparently caused the damage.

Right now, engineers are working on a temporary fix, called a grout curtain. Colonel Anthony Wright says the work looks initially positive, but it probably won't solve the problem.

Wright: "This is very unique material, it's not engineered structure we're trying to fix, we're trying to fix a big pile of rock and debris that Mother Nature left us 10,000 years ago. I'm confident that we can do something to improve it, I don't know how much."

Wright says during heavy rains, the Corps may have to release water into the Green River in order to relieve stress on the dam. There is a one–in–three chance those flows could top the river's levees. Thirty thousand people live in the flood zone, which includes parts of Kent, Tukwila, Auburn and Renton. The area is also a major industrial and distribution center.

A whole group of state, county and local officials gathered at the river's edge on Monday to talk about preparations. County Executive Kurt Triplett and others made liberal reference to that other recent flood disaster, Hurricane Katrina.

Triplett: "We've all been reading now the summaries of lessons from Katrina and they say don't ignore the signs; act, get your plans in place. And unfortunately that costs money. We're hoping that we'll be able to get that money back from the Federal government but we don't know that."

The $40 million that Triplett is asking for would go to shore up some of the most vulnerable levees along the Green River, and would also pay to move county services, like the elections department, out of the flood zone.

Governor Chris Gregoire says she has ordered state agencies to assist the county, as if it were already an emergency. The National Guard is working on evacuation plans and is identifying emergency shelter locations for up to 5,000 people.

But officials are also concerned that word hasn't completely gotten out among the population. County council member Julia Patterson says a recent survey found 75 percent of residents thought they were at low risk for flooding.

Patterson: "We need every single person in this valley to be aware of what their directive is. We have to make sure that that message is being relayed here, and that it's being relayed to every single home in the valley, every business, every church, every community center in the valley is aware of what is going on."

Officials say residents should have an emergency plan, an emergency kit, and they should buy flood insurance, before it's too late. It often takes 30 days to go into effect.

I'm Deborah Wang KUOW News.

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