Flood threat may cost King County millions

King County may have to spend millions of dollars to keep its South King County jail, courts, animal shelter, elections and permitting offices open in the face of potentially catastrophic flooding of the Green River this winter, the County Council learned Wednesday.

The stakes are even higher for the thousands of businesses and residents who face $2 billion to $3 billion in property damage if the river floods because of problems at the Howard Hanson Dam, Assistant County Executive Pam Bissonnette said in a briefing before the Metropolitan King County Council.

The damage estimate for the state's largest warehouse district comes from a draft report prepared by the Federal Emergency Management Agency (FEMA), Bissonnette said.

She said the Army Corps of Engineers, which owns and operates the Howard Hanson Dam, has also said it may take three to five years to fix the problem of water seeping through a hillside dam abutment. That solution — most likely a concrete cutoff wall — would cost hundreds of millions of dollars, she said.

County Executive Kurt Triplett will present a plan to the council in two weeks for protecting county property, along with a funding request — now estimated at $10 million to $35 million — to protect county operations from possible flooding of parts of Kent, Renton, Auburn and Tukwila, Bissonnette said.

County facilities at risk, include:

• King County Elections headquarters, opened at the end of 2007 in a $20 million building on Southwest Grady Way in Renton, could be flooded by up to 10 feet of water, Bissonnette said. It might be necessary to relocate the headquarters before flood season to avoid possibly disrupting the November election, she said.

• The Maleng Regional Justice Center in Kent, opened in 1997, which holds 800 prisoners in its jail and has courtrooms for 19 Superior Court judges and commissioners, could by flooded by up to 4 feet of water;

• The Department of Development and Environmental Services, which issues building and land-use permits, could receive up to 7 feet of water at its building on Oakesdale Avenue in Renton;

• The county's main animal shelter in Kent, up to 3 feet of water; and

• Aukeen District Court in Kent, up to a foot of water.

County officials are studying options for maintaining services at the at-risk buildings. Options include placing protective barriers around buildings and evacuating employees, jail inmates and shelter animals. Some offices, including the 1-½-year-old election headquarters in Renton, could be permanently moved to new locations.

Some of those costs could be reimbursed by the federal government. Acting Budget Director Beth Goldberg said it wasn't yet clear how flood preparations would affect the already troubled 2010 and 2011 budgets.

"We're really in an unprecedented, uncharted situation," she said. "We're getting new information all the time."

The council's Committee of the Whole sent to the full council without recommendation Triplett's request for authority to declare an emergency in advance of a flood so the county could avoid the red tape of standard procurement procedures.

The corps is now installing an underground "grout curtain" intended to slow water seepage. Until that seepage is controlled, the corps is restricting the amount of water that will be held behind the dam. That means more water may be released into the river during storms, resulting in "bigger and more frequent" flooding, Bissonnette said.

The valley hasn't had a major flood — once common in the valley — since the dam began operating in 1962.

Several County Council members urged Triplett's office Wednesday to organize a door-to-door campaign to reach all 20,000 valley residents of the flood danger. Council members were also unhappy about how long it will take the federal government to fix the problem at the dam.

"If we eventually have a flood that does 2 or 3 billion dollars damage and displaces the entire valley, I think we need to respectfully challenge the federal government to explain why they will take so long to come up with a permanent fix," Councilmember Julia Patterson of SeaTac said.

Bissonnette said the corps is working "very hard" to solve the problem. Because of the complexity of the seepage problem, she said, "it takes a while to do the studies to make sure you don't make a mistake."

Keith Ervin: 206-464-2105 or kervin@seattletimes.com