Drafter
Clerk 5/3/2007
Title
AN ORDINANCE authorizing the executive to enter into a project cooperative agreement with the United States Department of the Army, Corps of Engineers, for the repair of the Briscoe School levee on the Green river; and declaring an emergency.
Body
STATEMENT OF FACTS:
1. The Green river has historically experienced significant flooding and flood damages. The Howard A. Hanson dam was completed in 1962 and levees constructed to reduce flooding on the lower and middle Green river. A secondary purpose of the dam is water conservation and municipal water supply. The Howard A. Hanson dam is operated by the United States Department of the Army, Corps of Engineers ("the Corps").
2. January 2006 rainfall and snowmelt resulted in a discharge of eleven thousand two hundred cubic feet per second of floodwater at the Auburn gage based on a regulated outflow from Howard A. Hanson dam. This flood event resulted in approximately four hundred feet of rotational slope failure and an additional two hundred feet of damage along the right bank of a portion of the Green river levee system known as the Briscoe School Levee, located near river mile 16.5 , Section 2, Township 22 N, Range 4 E within the city of Kent.
3. The Briscoe School Levee is a non-federal levee maintained by King County, and the levee is active in the Public Law 84-99 Rehabilitation and Inspection program. King County has requested federal assistance to help repair the damaged levee, and will act as the local sponsor for the repair project.
4. The Corps, Seattle District, has prepared a Project Information Report for the Briscoe School levee. The report evaluated multiple repair alternatives. The recommended alternative selected by the Corps is the sponsor preferred levee setback alternative. The Corps defines the levee setback alternative as a "betterment" rather than repairing the levee to the preflood condition, which is defined as the least cost alternati...
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