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Mr. <br />Ted Feig <br />- 2 - <br />June 8, 1981 <br />Soil Texture at <br />Hole <br />Elevation <br />Depth(inches) <br />Bottom of Hole <br />Percolation Rate(min/in) <br />A <br />98.4 <br />26 <br />Sandy clay loam <br />2.8 <br />B <br />97.7 <br />28 <br />Clay loam <br />3.9 <br />C <br />98.4 <br />28 <br />Sandy clay loam <br />6.4 <br />D <br />97.7 <br />26 <br />Clay loam <br />4.9 <br />05 <br />97.7 <br />24 <br />Sandy clay loam <br />6.9 <br />#6 <br />97.5 <br />26 <br />Sandy clay loam <br />3.9 <br />Measured percolation rates are rapid for the texture of the soil material in <br />which the percolation tests were performed. <br />The mound is designed to serve a four bedroom house. Design sewage flow is <br />600 gallons per day. With a design infiltration rate of 1.2 gallons per square <br />foot per day for the medium sand fill material of the mound, the required rock <br />bed area of the mound is 500 square feet. <br />600 gal/day - 1.2 gal/ft2/day - 500 ft` <br />The mound design utilizes a rock bed 10 feet wide by 50 feet long which provides <br />the needed rock bed area. <br />With 3 to 1 finished slopes and 1.5 feet of medium sand fill below the rock <br />bed, the mound will cover an area 31 feet wide by 71 feet long. <br />The basal area of the medium sand fill material is 1,625 square feet (25 feet <br />wide by 65 feet long). The design infiltration rate of natural soil with a <br />percolation rate of up to 60 minutes per inch is 0.74 gallons per square foot <br />per day. Therefore the required basal area is <br />600 gal/day r 0.74 gal/ft2/day - 811 ft2. <br />This calculation shows that sufficient basal area is provided by the design. <br />The pressure distribution system of the mound consists of Schedule 40 PVC <br />plastic pipe. The supply pipe and manifold are 2.0 inch inside diameter <br />pipe. The supply pipe should slope back towards the pumping chamber so that <br />it drains after the mound is dosed. Tho laterals are 1.5 inch inside diameter <br />pipes. The laterals should have 1/4 inch diameter holes drilled at a spacing <br />of 3.0 feet. The laterals should be assembled to the manifold so that the <br />holes point downwards into the rock bed. The distal ends of the laterals should <br />be capped. Also, the last hole in each lateral should be drilled horizontally <br />in the end cap near the crown of the pipe to facilitate air venting. <br />