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A RESOLUTION adopting objectives for Provisional Levels of Protection for the Green River System-Wide Improvement Framework.
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WHEREAS, in the Spring of 2013, the King County Flood Control Zone District ("District"), in cooperation with numerous partners, commenced preparation of the Green River System-Wide Improvement Framework ("SWIF") to protect the Green River valley's economic base from flooding, while strengthening the resiliency of its natural systems; and
WHEREAS, the SWIF will provide for management of the Green River valley in a manner that meets multiple and often competing federal, state and local mandates associated with endangered species recovery, flood protection, clean water standards and economic health; and
WHEREAS, the SWIF will include a collective vision across diverse partners regarding flood protection goals and long-term actions that are necessary to achieve this vision; and
WHEREAS, the SWIF planning process is anticipated to be completed in February 2015; and
WHEREAS, the major elements of the SWIF planning process are (1) to establish and involve a stakeholder committee, (2) to conduct public outreach, (3) to determine goals, objectives, vision and strategy, (4) to evaluate flood risks and level of protection alternatives, (5) to assess habitat restoration opportunities and vegetation management alternatives and (6) to develop capital projects and a financing plan for them; and
WHEREAS, District approval of the final SWIF will allow the District to remain eligible for capital project funding under PL 84-99; and
WHEREAS, as part of the SWIF planning process, five technical memoranda have been issued: (1) Aquatic, Floodplain and Riparian Vegetation and Habitat Assessment, (2) Geomorphology Assessment, (3) Geotechnical Assessment, (4) Hydraulic Assessment and (5) Economic Analysis; and
WHEREAS, as part of the planning process, a Current Conditions Report has been issued, a portion of which is called a Vegetation and Habitat Resources Technical Memorandum; and
WHEREAS, among other things, the planning process so far has revealed that (1) levee overtopping that exceeds design protection will result in floodplain inundation of one to 10 feet or more, (2) systemwide annual damages due to flooding are estimated to be $47.1 million (per HEC-FDA modeling), (3) present value damages due to flooding are estimated to be $1.1 billion (based on fifty years and a 3.5 percent discount rate), and (4) 5,371 residential structures are estimated to be located in the SWIF planning area; and
WHEREAS, the board of supervisors of the District desires to approve objectives relating to provisional levels of protection for the SWIF; now, therefore
BE IT RESOLVED BY THE BOARD OF SUPERVISORS OF THE KING COUNTY FLOOD CONTROL ZONE DISTRICT:
SECTION 1. The board of supervisors of the King County Flood Control Zone District ("District") approves provisional levels of protection ("LOP") flooding goals for the Lower Green River portion of the Green River System-Wide Improvement Framework ("SWIF"), as shown on Attachment A to this resolution. The colors on the Attachment A indicate the following:
1. LOP Goal 'A' (green lines): Maintain the current LOP and/or the shoreline condition over time.
2. LOP Goal 'B' (orange lines): Increase the LOP to a flow rate to be determined, pending completion of more detailed analysis during the forthcoming SWIF Alternatives Phase. These sections of the shoreline will be evaluated during the SWIF Alternatives Phase, to better understand the costs, benefits and tradeoffs associated with changing the LOP in a given shoreline location. At the end of the Alternatives Phase, the detailed analysis of the LOP Goal 'B' portions of the shoreline will inform the District's decision on whether or not to change this goal to 'A', which would maintain the current LOP, or 'C', or increase the level of protection to a higher flow rate up to and including a maximum provisional flow rate of 18,800 cfs, which would achieve maximum LOP; and
3. LOP Goal 'C' (red lines): Achieve the maximum LOP of 18,800 cfs, the flow rate being used as a placeholder for 'C', pending approval of the SWIF by the District. All PL84-99 levees have maximum LOP assigned (red).