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Kittitas County, WA <br />$ 174.06.010 CRITICALAREAS $ 174.06.020 <br />CHAPTER 17A.06 <br />GEOLOGICALLY HAZARDOUS AREAS <br />S 17A.06.010. Purpose and intent. <br />The purpose of this Chapter is to protect human life and safety, prevent damage to structures and property, <br />and minimize impacts to water quality and fish and wildlife caused by geologic hazards. <br />(Ord.202l-016,2021) <br />$ 17A.06.020. Designation, classification, and mapping. <br />2 <br />Designation. Lands classified as landslide, erosion (including channel migration zones), alluvial fan, <br />seismic, and mine hazatd areas, are hereby designated as geologically hazardous areas. <br />Classification. <br />Potential landslide hazard areas. Landslide hazard areas shall include areas potentially subject to <br />landslides based on a combination of geologic, topographic, and hydrologic factors. They <br />include any areas susceptible because ofany combination ofbedrock, soil, slope (gradient), slope <br />aspect, structure, hydrology, or other factors. Potential landslide hazard areas include but are not <br />limited to the following areas: <br />i. Areas of historic failures; <br />ii. Areas designated as quaternary slumps, earth-flows, mudflows, or landslides on maps <br />published by the U.S. Geological Survey or Washington State Department of Natural <br />Resources; <br />iii. Areas with all three (3) of the following characteristics: <br />l. Slopes steeper than fifteen percent (15%); <br />2. Hillsides intersecting geologic contacts with a relatively permeable sediment <br />overlying a relatively impermeable sediment or bedrock; and <br />3. Springs or groundwater seepage; <br />iv. Areas that have shown movement andlor are underlain or covered by mass wastage debris; <br />v. 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 />vi. Slopes having gradients steeper than eighty percent (80%) subject to rock fall during <br />seismic shaking; <br />vii. Areas that show evidence of, or are at risk from snow avalanches; and <br />viii. 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 competent bedrock. A slope is delineated by <br />establishing its toe and top and measured by averaging the inclination over at least ten (10) <br />feet of vertical relief; <br />ix. Potentially unstable slopes resulting from river erosion or undercutting; <br />a. <br />Downloaded llom https://ecode360.com/Kl6857 on 2025-05-15