The Director of King County’s Office of Emergency Management told the King County Council’s Committee of the Whole today that while the risk may be lower, preparations in the event of potential release of water from the Howard Hanson Dam continue.
“The Army Corps has provided good information about the current condition of the dam, but the people of the Green River Valley are living in a flood plain,” Hillman Mitchell said. “We need to make sure we are prepared. We want to make sure that everybody stays ready and vigilant this winter.”
Mitchell told the Committee with expectations of a wetter winter this year, his department is continuing its outreach to communities in the path of a potential flood should water need to be released from behind the dam.
“Now is not the time to relax,” King County Councilwoman Julia Patterson said, who represents the Green River Valley. “While the heightened risk of flooding still exists, valley residents and businesses must continue to prepare. I am pleased to see King County work to prepare the people and commerce for the possibility of flooding.”
Council Chair Bob Ferguson said, “Although a lot of progress has been made and the risk of flooding has been mitigated, we must remain vigilant in our emergency planning efforts while we work with our federal and local partners for additional repairs.”
A grout curtain put in place last winter by the U.S. Army Corps of Engineers has reduced the risk water would need to be release from behind the structure to relieve pressure on the dam from 1-in-4 to 1-in-60. Additional repairs, which are targeted for completion in 2012, are expected to further reduce the risk of flooding.
Mitchell told the committee that the regional public notification system, created by King County and the cities in the Green River Valley was tested earlier this year with positive results. Working with State Department of Commerce and local agencies, the Office of Emergency Management has developed a fact sheet for businesses in the Green River Valley to dispel some of the myths surrounding the potential for flooding.
Interagency cooperation between local, state and federal governments continues in the creation of response and recovery plans in the event of flooding in the Green River Valley. Mitchell said that includes the office of Emergency Management working on agreements to ensure there will be mass care facilities available if evacuations are necessary.
Mark Issacson, Director of the County’s Water and Land Resources Division (WLRD), told the committee that many of the preparations put in place last year remain on the banks of the Green River, including the 26 miles of “supersacks”— oven-sized plastic and fiber bags filled with rock and gravel. Working in conjunction with the Army Corps of Engineers, repairs to the levee system that protects the Green River Valley have also been made.
Isaacson said WLRD’s has maintained its community outreach through an automated flood warning system which has over 3,200 subscribers. It has also updated its flood information brochure, which is available in several languages. The department continues to work with community groups and the Red Cross to ensure that vulnerable populations and non-English speaking communities also have access to flood preparation information. WLRD will participate in public meetings in the Green River Basin and work with communities along the Snoqualmie and Cedar Rivers to increase awareness on flood preparations.
