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<br />Kittitas County Board of County Commissioners Shoreline Master Program Adopting Ordinance <br />Kittitas County Shoreline Master Program Exhibit D | March 2016 | Page 274 of 339 <br /> <br />d. Slopes that are parallel or sub-parallel to planes of weakness (such as bedding planes, <br />joint systems, and fault planes) in subsurface materials; <br />e. Slopes having gradients steeper than eighty percent (80%) subject to rock fall during <br />seismic shaking; <br />f. Areas potentially unstable as a result of rapid stream incision, stream bank erosion, and <br />undercutting by wave action, including stream channel migration zones; <br />g. Areas that show evidence of, or are at risk from snow avalanches; <br />h. Areas located in a canyon or on an active alluvial fan, presently or potentially subject to <br />inundation by debris flows or catastrophic flooding; and <br />i. Any area with a slope of forty percent (40%) or steeper and with a vertical relief of ten <br />(10) or more feet except areas composed of bedrock. A slope is delineated by <br />establishing its toe and top and measured by averaging the inclination over at least ten <br />(10) feet of vertical relief. <br />3. Classification: Erosion hazard areas – areas containing soils that may experience significant <br />erosion, including: <br />a. Slopes forty percent (40%) or steeper with a vertical relief of ten (10) or more feet, <br />except areas composed of consolidated rock. <br />b. Concave slope forms equal to or greater than fifteen percent (15%) with a vertical relief <br />of ten (10) or more feet, except areas composed of consolidated rock. <br />c. Channel migration zones: Areas within which the stream channel can reasonably be <br />expected to migrate over time as a result of normally occurring hydrological and related <br />processes when considered with the characteristics of the river and its surroundings. <br />Such hazards are characterized by abandoned channels, ongoing sediment deposition <br />and erosion, topographic position, and changes in the plant community, age, structure <br />and composition. <br />4. Classification: Seismic hazard areas – lands subject to severe risk of damage as a result of <br />earthquake induced ground shaking, slope failure, settlement, soil liquefaction, or surface <br />faulting the following classifications shall be designated as seismic hazard and are subject <br />to the requirements of this Section. <br />5. Classification: Volcanic hazard areas – areas subject to pyroclastic flows, lava flows, debris <br />avalanche, inundation by debris flows, mudflows, or related flooding resulting from volcanic <br />activity. There are no active or dormant volcanoes located within Kittitas County; however <br />Mount Rainer and Mount St. Helens are relatively near. Hazards to Kittitas County residents <br />from these volcanoes are limited to ash deposition. <br />6. Classification: Mine hazards areas – areas underlain by abandoned mine shafts, secondary <br />passages between shafts tunnels, or air vents. Mine hazards include subsidence, which is <br />the uneven downward movement of the ground surface caused by underground workings <br />caving in; contamination to ground and surface water from tailings and underground <br />workings; concentrations of lethal or noxious gases; and underground fires. <br />7. Mapping: The approximate location and extent of geologically hazardous areas are shown <br />on maps maintained by the County. These maps shall be advisory and used by the <br />Administrator to provide guidance in determining applicability of the standards to a property. <br />These maps shall be updated periodically as new information becomes available. <br /> <br />17B.05.020P Geologically hazardous areas – reporting and protection standards. <br />1. New shoreline uses and developments shall be located, designed, constructed, and <br />maintained to avoid geologically hazardous areas. Impact avoidance measures shall <br />include, but not be limited to, locating the use/development outside of the hazard area, <br />reducing the number, size or scale of buildings, driveways and other features; altering the <br />configuration or layout of the proposed development; using environmentally favorable <br />construction materials; implementing special engineering methods for construction,