Ordinance - #89-21 - 09/12/1989 - Laserfiche WebLink

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Subd. 4 - Mounds 1. Mounds may be constructed on soils having the site or soil conditions specified in Section 150.014G. 2. The soil percolation rate in all layers of the natural or fill soil to a depth of at least twenty-four (24) inches below the sand shall be faster than one hundred twenty (120) minutes per inch. 3. The allowable absorption area loading rate must be determined according to Table III by the percolation rate of the 12 inches of original or fill soil immediately under the sand layer. TABLE III Percolation rate of original soil under sand layer, minutes Allowable absorption area loading rate gallons/day square feet per per square foot gallons per day 6 to 15 0.79 1.27 16 to 30 0.60 1.67 31 to 45 0.50 2.00 46 to 60 0.45 2.20 61 to 120 0.24 4.20 4. Below the sand layer, there shall be at least one (1) layer of soil, either natural or fill, at least twelve (12) inches thick, which has a percolation rate slower than five (5) minutes per inch (loamy sand). 5. Wherever possible, mounds shall be located on flat areas or crest of slopes. Mounds shall not be located on natural slopes of more than three per cent (3%) if the percolation rate is slower than sixty (60) minutes per inch to a depth of at least twenty-four (24) inches below the sand layer. 6. Mounds shall not be located on slopes exceeding six per cent (6%) if the soil percolation rate is slower than thirty (30) minutes per inch to a depth of at least twenty-four (24) inches below the sand layer. 7. Mounds shall not be located on natural slopes exceeding twelve per cent (12%) under any soil percolation rate conditions. 8. The bottom area of the filter material shall be sized on the basis of two hundred (200) square feet per bedroom or eight- three hundredths (0.83) square feet per gallon of waste per day. 9