2019_KittitasCountyHMP_Volume 1_For Adoption

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CHAPTER 11. FLOOD 11-23 As participants in the NFIP, Kittitas County and the partner cities have adopted flood damage prevention ordinances pursuant to the participation requirements. While these ordinances do not prohibit new development within the floodplain, they include new development provisions that account for the risk inherent to the floodplain. The combination of the GMA provisions, critical areas regulations and NFIP flood damage prevention provisions equips the municipal planning partners with adequate tools to address new development in the floodplain. As pressures mount for growth into areas with flood risk, these tools could be enhanced with higher regulatory standards to increase the level of risk reduction on new development. Areas likely to flood are not expected to expand significantly based on development trends in the next five years. Additional information on future growth in the County is presented in Chapter 4 of this plan. 11.8. SCENARIO The primary water courses in Kittitas County have the potential to flood at irregular intervals, generally in response to a succession of intense winter rainstorms. Storm patterns of warm, moist air usually occur between early November and late March. A series of such weather events can cause severe flooding in the planning area. The worst-case scenario is a series of storms that flood numerous drainage basins in a short time. This could overwhelm the response and floodplain management capability within the planning area. Major roads could be blocked, preventing critical access for many residents and critical functions. High in- channel flows could cause water courses to scour, possibly washing out roads and creating more isolation problems. In the case of multi-basin flooding, the County would not be able to make repairs quickly enough to restore critical facilities and infrastructure. Flooding events could have a significant impact on the Kittitas County economy. Businesses could be flooded, and be unable to reopen until necessary repairs are made. A FEMA Ready Business report found that 40% of small businesses don’t reopen after a hazard event, and 25% more small businesses will close one year after the hazard event. Flooding frequently results in roads and bridges becoming impassable, making it difficult for residents to reach their place of work. With 26% of the population employed in local and state government, there could be major impacts on the basic functioning of the government. Other industries that will be particularly impacted will be Accommodation and Food Service with 18.1 percent of Kittitas County employees, Retail Trade with 12.1 percent, and Health Services with 8.7 percent 11.9. ISSUES The planning team has identified the following flood-related issues relevant to the planning area: • The extent of flood-protection provided by flood control facilities (dams, dikes and levees) is not known due to the lack of an established national policy on flood protection standards. • The risk associated with the flood hazard overlaps the risk associated with other hazards such as earthquake and landslide losses. This provides an opportunity to seek mitigation alternatives with multiple objectives that can reduce risk for multiple hazards. • There is no consistency of land-use practices within the planning area or the scope of regulatory floodplain management beyond the minimum requirements of the NFIP. • Climate change could alter flood conditions in Kittitas County. • More information is needed on flood risk to support the concept of risk-based analysis of capital projects. • There needs to be a sustained effort to gather historical damage data, such as high water marks on structures and damage reports, to measure the cost-effectiveness of future mitigation projects.