Ord 2625 - TMC Title 18 Chapters - Critical Areas Regulations

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B. EXEMPTIONS. The following areas are exempt from regulation as geologically hazardous areas: 1. Temporary stockpiles of topsoil, gravel, beauty bark or other similar landscaping or construction materials; pad; 2. Slopes related to materials used as an engineered pre -load for a building 3. Roadway embankments within right-of-way or road easements; and 4. Slopes retained by approved engineered structures. C. ALTERATIONS. 1. Prior to permitting alteration of an area of potential geologic instability, the applicant must demonstrate one of the following: a. There is no evidence of past instability or earth movement in the vicinity of the proposed development, and, where appropriate, quantitative analysis of slope stability indicates no significant risk to the proposed development or surrounding properties; or b. The area of potential geologic instability can be modified or the project can be designed so that any potential impact to the project and surrounding properties is eliminated, slope stability is not decreased, and the increase in surface water discharge or sedimentation shall not decrease slope stability. 2. Where any portion of an area of potential geologic instability is cleared for development, a landscaping plan for the site shall include replanting of preferably native trees (an equal mix of evergreen and deciduous), shrubs and groundcover. The landscaping plan must be approved by the Director. Replacement vegetation shall be sufficient to provide erosion and stabilization protection. 3. Critical facilities shall not be sited within or below an area of potential geologic instability unless there is no practical alternative (demonstrated by the applicant). 4. Land disturbing activities in an area of potential geologic instability shall provide for storm water quality and quantity control, including preparation of a TESC and permanent drainage plan prepared by a professional engineer licensed in Washington. 5. Unless otherwise provided or as part of an approved alteration, removal of vegetation from an area of potential geologic instability or its buffer shall be prohibited. When permitted as part of an approved alteration, vegetation removal shall be minimized to the extent practicable. 6. Surface drainage, including downspouts, shall not be directed across the face of an area of potential geologic instability; if drainage must be discharged from the top of a hazard to its toe, it shall be collected above the top and directed to the toe by tight line drain, and provided with an energy dissipative device at the toe for discharge to a swale or other acceptable natural drainage areas. w:\Legislative Development\Critical Areas update 2-25-20 MD:bjs Review and analysis by Barbara Saxton Page 36 of 87