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I I I I I I I I I I I I I I I I I I I I Any land use in a potentially unstable slope area shall avoid: a. Cutting into slope without providing adequate mechanical support. b. Adding water to the slope that would cause decreased stability. c. Adding weight to the top of the slope. d. Removing vegetation from the slope without adequate revegetation. e. Over-steeping slopes, 3. EXPANSIVE SOIL AND ROCK: H. G. 1041 defi nes expans i ve soil and rock as follows: "Expansive Soil and Rock means soil and rock which contains clay and which expands to a significant degree upon wetting and shrinks upon drying. " The Tomichi, (ToE); Bross, (BrF); and Troutville, (TrE) soils have a low shrink- swell potential. The remaining soils found in the study area were classified as too variable for valid estimates to be made. ~ny developrlJent or activity in an identified area of expansive soil and rock shall only be permitted upon approval of engineered foundations and floor systems designs. Engineered design for correction of adverse conditions shall include a suitable com- bination of the following four methods: a. Foundation design b. Well-planned site drainage c. Landscaping to enhance drainage d. Interior construction details as described in Special Publication ~~~ (Colorado Geological Survey, 1974), pp. 68-76. 4, SLOPES 15 PERCENT OR GREATER: Development of slopes which are excessive present a number of hazards. On slopes 10 percent or greater, development shall be prohibited. Development shall be dis- couraged on slopes 15 percent or greater unless problems of stability and erosion can be overcome. Any development approval shall be based on a detailed site survey 'ncluding geologic and engineering analysis and shall comply with the following: a. Cuts shall not be made into slopes steeper than 30 percent unless mechanical support is provided. b. Cuts and fills, and grading and scraping shall be confined to the minimum area needed for construction. c. Steepness of cut and fill slopes shall be the maximum which will insure stability and still allow revegetation. d. Development plans shall include reasonable but adequate control measures. Large tracts should be developed in small workable units without leaving large areas for long periods. e. l!se mulches or temporary cover or exposed soil areas and re-establish pern:anent vegetati on a'ld ins ta 11 erosion control measures as soon as possible. f. Incorporate natural drainage patterns into the development, Culverts, sediment basins and other engineering measures should be used where necessary to control erosion. g, Soil absorption sewage disposal systems should not be placed on slopes steeper than 15 percpnt. 5. EROSION: Erosion and sediment deposition is part of the natural cycle which takes place 8