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CHAPTER 12. LANDSLIDE <br />12-8 <br />Loss estimations for the landslide hazard are not based on modeling utilizing damage func tions, because <br />no such damage functions have been generated. Instead, loss estimates were developed representing <br />10 percent, 30 percent and 50 percent of the assessed value of exposed structures. This allows emergency <br />managers to select a range of economic impact based on an estimate of the percent of damage to the general <br />building stock. Damage in excess of 50 percent is considered to be substantial by most building codes and <br />typically requires total reconstruction of the structure. Table 12-3 shows the general building stock loss <br />estimates for landslide risk areas. <br />Table 12-3. Estimated Losses in Landslide Risk Areas <br />Jurisdiction <br />Buildings <br />Exposed to <br />Hazard Area <br />Assessed Value <br />of Buildings <br />Exposed <br />10% Damage 30% Damage 50% Damage <br />Cle Elum 0 $0 $0 $0 $0 <br />Ellensburg 0 $0 $0 $0 $0 <br />Kittitas 0 $0 $0 $0 $0 <br />Roslyn 0 $0 $0 $0 $0 <br />South Cle Elum 0 $0 $0 $0 $0 <br />Unincorporated 365 $164,279,000 $16,427,900 $49,283,700 $82,139,510 <br />Total 365 $164,279,000 $16,427,900 $49,283,700 $82,139,510 <br /> <br />12.6.3 Critical Facilities and Infrastructure <br />There were no critical facilities exposed to the landslide hazard area. Several types of infrastructure are <br />exposed to mass movements, including transportation, water and sewer and power infrastructure. Highly <br />susceptible areas of the county include mountain and coastal roads and transportation infrastructure. At this <br />time all infrastructure and transportation corridors identified as exposed to the landsl ide hazard are <br />considered vulnerable until more information becomes available. <br />12.6.4 Environment <br />The environment vulnerable to landslide hazard is the same as the environment exposed to the hazard. <br />12.7. FUTURE TRENDS IN DEVELOPMENT <br />Landslide hazard areas are included in “geologically hazardous areas,” one category of critical areas <br />regulated under the state GMA for Kittitas County. “Landslide hazard areas” are defined as areas potentially <br />subject to mass earth movement based on a combination of geologic, topographic, and hydrologic factors, <br />with a vertical height of 10 feet or more. These include the following: <br />– Areas of historical landslides as evidenced by landslide deposits, avalanche tracks, and <br />areas susceptible to basal undercutting by streams, rivers or waves <br />– Areas with slopes steeper than 15 percent that intersect geologic contacts with a relatively <br />permeable sediment overlying a relatively impermeable sediment or bedrock, and which <br />contain springs or groundwater seeps <br />– Areas located in a canyon or an active alluvial fan, susceptible to inundation by debris <br />flows or catastrophic flooding. <br />Kittitas County and its planning partners appear to be well equipped to deal with future growth and <br />development within the planning area. The landslide hazard portions of the planning area are regulated by