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 alternative. The levee setback alternative will repair the damaged section of the levee to a one-hundred-year level of flood protection at the project location.
5. The levee setback alternative was chosen as the preferred alternative by both the Corps and King County, since it will provide one-hundred-year level of flood protection. The no-action alternative could eventually result in a breach and subsequent failure of the levee.
6. The estimated cost for rehabilitation of the Briscoe School Levee to the least cost alternative is $553,600, including design and construction. The levee setback alternative, including design and construction, is estimated to cost $834,000. King County is responsible for twenty percent of the total construction cost for portion of the levee construction within the existing footprint of the levee, and one hundred percent of the additional construction cost for the portion to be constructed beyond its existing footprint, or the betterment cost, or the difference between the levee setback alternative and the least cost alternative, and all necessary utility relocates, real estate, and disposal costs. King County's total cost share is equal to forty-four percent of the total construction costs, or $368,900. King County matching funds will be contributed by the river improvement fund and the Green River Flood Control Zone District fund.
7. King County is responsible for obtaining all necessary real estate, providing appropriate disposal area or areas, utility relocates, and obtaining local permits. The Corps will be responsible for federal permits, which include a Section 7 consultation with the National Marine Fisheries Services and the United States Fish and Wildlife Service, in accordance with Section 7 of the Endangered Species Act of 1973, to determine whether federally listed or proposed threatened or endangered species and/or candidate species in the project vicinity could be affected by construction of this project.
8. King County will enter into a cooperative agreement with the Corps to establish the roles and responsibilities and identify the cost shares.
9. The repair will involve reconstruction of the failing section of the levee with a stable levee set-back configuration and habitat features. Construction will be phased in order to complete the project this summer. Phase I will entail the King County road services division completing most of the excavation work down to the toe starting in July, followed by Phase II in which the Corps contractor will reconstruct the toe, lower and upper slopes, place habitat structures, and complete restoration of the vegetation, trail and temporary work areas.
BE IT ORDAINED BY THE COUNCIL OF KING COUNTY:
SECTION 1. The King County executive is authorized to enter into a cooperative agreement on behalf of King County with the United States Department of the Army, Corps of Engineers, substantially in the form of the agreement attached as Attachment A to this ordinance, for the rehabilitation of the Briscoe School levee on the Green river.
SECTION 2. The county council finds as a fact and declares that an emergency exists and that this ordinance is necessary for the immediate preservation of public peace,
health or safety, or for the support of county government and its existing public institutions.
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