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Kittitas County,WA <br /> § 17A.02.470 KITTITAS COUNTY CODE § 17A.02.470 <br /> § 17A.02.470. Landslide hazard areas. <br /> "Landslide hazard areas" are areas potentially subject to landslides based on a combination of geologic, <br /> topographic, and hydrologic factors. They include any areas susceptible because of any combination of <br /> bedrock, soil, slope(gradient), slope aspect, structure,hydrology, or other factors.A slope is delineated by <br /> establishing its toe and top and measured by averaging the inclination over at least ten(10) feet of vertical <br /> relief.Potential landslide hazard areas include but are not limited to the following areas: <br /> 1. Areas designated as quaternary slumps,earth-flows,mudflows,or landslides on maps published <br /> by the U.S. Geological Survey or Washington State Department of Natural Resources. <br /> 2. Areas with all three(3) of the following characteristics: <br /> a. Slopes steeper than fifteen percent(15%); <br /> b. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a <br /> relatively impermeable sediment or bedrock; and <br /> C. Springs or groundwater seepage. <br /> 3. Areas that have shown movement and/or are underlain or covered by mass wastage debris; <br /> 4. Slopes that are parallel or sub-parallel to planes of weakness (which may include but not <br /> be limited to bedding planes, soft clay layers, joint systems, and fault planes) in subsurface <br /> materials; <br /> 5. Slopes having gradients steeper than eighty percent (80%) subject to rock fall during seismic <br /> shaking; <br /> 6. Areas that show evidence of, or are at risk from snow avalanches; and <br /> 7. Any area with a slope of forty percent (40%) or steeper and with a vertical relief of ten(10) or <br /> more feet except areas composed of competent bedrock. <br /> 8. Potentially unstable slopes resulting from river erosion or undercutting. <br /> 9. Areas that show past sloughing or calving of sediment or rocks resulting in a steep slope that is <br /> poorly vegetated. <br /> 10. Deep-seated landslide areas characterized by one or more of the following features,which may <br /> be evident in aerial images,topographic maps,LiDAR imagery or on the ground: <br /> a. scalloped ridge crests at the top of the slope, <br /> b. crescent shaped depressions, <br /> C. head scarps, <br /> d. side scarps, <br /> e. ponds or sag areas on mid slopes, <br /> f. benches and scarps on mid slope areas, <br /> g. hummocky ground, <br /> Downloaded from https:Hecode360.com/KI6857 on 2025-05-15 <br />