Comp Plan 1974-1977 FILE #1 - Laserfiche WebLink

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d. Rapi_dly ~Permeabl e Soils. 1. Filter material for a soil treatment unit using gravity distribution of effluent shall not be placed in contact with original soil having a percolation rate faster than one-half minute per inch. 2. For coarse soils having a percolation rate faster than one-half minute minute per inch, at least six inches of sandy loam textured soil having a percolation rate betwen five and fifteen minutes per inch after placement (loamy sand to sandy loam) shall be placed between the filter material and the coarse soil along the excavation bottom and sidewalls. 3. For soils with percolation rates between one-half and five minutes per inch, at least one of the following treatment techniques shall be used. (a) Provide at least six inches of sandy loam textured soil with a percolation rate between five and fifteen minutes per inch after placement between the filter material and the coarse soil. (b) Divide the total soil treatment area into at least four equal parts connected serially. e. Mounds. 1. Mounds may be constructed on soils having the site or soil conditons specified in Section 4.07. 2. The soil percolation rate in all layers of the natural or fill soil to a depth of at least 24 inches below the sand shall be faster than 120 minutes per inch. 3. Below the sand layer there shall be at least one layer of soil, either natural or fill, at least 12 inches thick, which has a percolation rate slower than five minutes per inch (loamy sand). 4. Wherever possible, mounds shall be located on flat areas or crests of slopes. Mounds shall not be located on natural slopes of more than three percent if the percolation rate is slower than 60 minutes per inch to a depth of at least 24 inches below the sand layer. 5. Mounds shall not be located on slopes exceeding six percent if the soil percolation rate is slower than 30 ,~inutes per inch to a depth of at least 24 inches below the sand layer. 18