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07/69/2008 10:37 952-955-5671 BURNS EXCAUATING PAGE 09 <br /> MOUND DE51GN WORKSHEET (For flows up to 1200 gpd) <br /> A. Estimated 900 gpd or measured X 1.5 ^ gpd <br /> B. SEPTIC TANK LIQUID VOLUMES: 2500 <br /> G. SITE EVALUATION INFORMATION <br /> 1. Depth of clea� sar�d req. 18.00 inches or 1.50 feet <br /> 2. Depth of percolation tests = 12 inches <br /> 3. Soil Texture LOAM <br /> 4. Perc. Rate 20 mpi <br /> 5. Land Slope 4.0 percent <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply flow rate by 0.83 to obtain required area of rock layer: <br /> 900 gpd X 0.83 sq fflgpd 747.00 sq. ft. rock area <br /> 2. Select width of rock layer (Max �o� if<�20, ar max 5' if>120) 10.0 feet <br /> 3. Rvckbed length �arean�drn� 747.00 sq. ft. / 10.0 feet = 74.7 feet <br /> Round off 75 <br /> E. ROCK VOLUME <br /> 1. Multiply rock area by rock depth to get cubic feet of rock: <br /> 750 sq. ft X 1.0 = foot= 750 cubic feet <br /> Z. Divide cubic feet by 27 to get cubic yards: <br /> �50 cu. ft. / 27 = 27.8 cubic yards <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons: <br /> 27.8 cu. yd. X 1.4 = 38.9 tons X 10 °r6 = 42.8 tons req'd <br /> F. ADSORPTION WIDTH <br /> 1. Percolation rate in to 12 inches of soil is 20.Q mpi <br /> Soil Texture is Loam <br /> 2. Select allowable soil loading rate from table: 0.60 gpd / sq, ft. <br /> PEC RATE MPI 301L 7EX'TUR GPD I SQ,FT. RA110 <br /> FA TER�0.1 C ARSE 3AN0 1.20 9,oa <br /> 0.1 TO S SAND 1.20 1�00 <br /> 0,1 TO 5 F1NE SAND 0.90 200 <br /> 9 TO 15 3ANOY I.OAM 0.T8 1.62 <br /> 19 TO 90 LOAM 0,60 2.00 <br /> 81 TD d5 SILT LOAM 0,50 2�4� <br /> JB TO 60 CI.AY LOAM D.AS 2.B7 <br /> BO T0120 CLAY 0,�� 6.0� <br /> �120 CLAY 0.20 9.00 <br /> 3. Calculate adsorptian width ratio by dividing rock layer loading rate <br /> of 1.20 gpd !sq. ft. by allowable soif loading rate: <br /> 1.20 gpd/ sq_ divided by 0.60 gpd ! sq. ft. equals 2.00 <br /> 4. Multiply adsorption width ratio by rock layer width to get required adsorptian width: <br /> 2.00 X 10,0 feet = 20.0 feet adsorption width <br /> PAGE 4 OF 12 <br />