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MOUND DESIGN WORKSHEET <br /> (For Flows up to 1200 gpd) <br /> A. FLOW Estimated Sewage Flow in Gallons per Day(gpd) 1, <br /> Estimated 900 gpd Nuof mber Type I Type II Type III Type ry <br /> or measured - x 1.5 = - gpd. Bedrooms <br /> 2 300 225 180 60% <br /> 3 450 300 218 •t <br /> B. SEPTIC TANK LIQUID VOLUMES 4 600 375 256 <br /> 5 750 450 294 is <br /> 1-)a S0 4� 1-/C)U 0 gallons 6 900 525 332 the <br /> 7 1050 600 370 �t, <br /> 8 12(0 675 408 <br /> C. SOILS (refer to site evaluation) Number <br /> 1. Depth to restricting layer = �a �0 3�'' inches 8 sak , <br /> 2. Depth of percolation tests = 1 a inches <br /> 3. Percolation rate 3 .'7 mpi 23 alb ,7050°0 1 s o <br /> 5 or 6 1,500 2,250 <br /> 4. Land slope S % 7 a 8 2.0003.000 <br /> ova 9 See fig.C-6 (x 1.5) <br /> D. ROCK LAYER DIMENSIONS <br /> 1. Multiply flow rate by 0.83 to obtain required area of rock <br /> layer:A x 0.83 = <br /> 100 gpd x 0.83 sq. ft./gpd = r?14 sq. ft. <br /> 2. Select width of rock layer (10 feet or less) = ft. <br /> 3. Length of rock layer = area i width= Rock Bed <br /> '? sq. ft.-t- io ft. = 'Lc- ft. ti•�NM•ti•ti••.Mti•tiNiti•r f~r~1tif <br /> r•f•r•r.r•r•�•r•r•r r.r•r.r•r•r•r•r'Width <10 ft. <br /> ~• •1•ti•ti•ti.ti•ti•4•ti•ti•ti•'ti•ti••.•4•ti• <br /> 5555555555555555555Y; <br /> E. ROCK VOLUME Length <br /> 1. Multiply rock area by rock depth to get cubic feet of rock; - <br /> 0 r-) sq.ft. x/.1.7(ft. _ 'NY cu. ft. <br /> 2. Divide cu. ft.by 27 cu. ft./cu. yd. to get cubic yards; <br /> Oedt-1 cu. ft. y 27= a� cu. yd. <br /> 3. Multiply cubic yards by 1.4 to get weight of rock in tons; <br /> aS cu. yd. x 1.4 ton/cu. yd. _ L}0 tons. <br /> F. ADSORPTION WIDTH 1'0`A"0-1 absorption width Siring Lble <br /> 1. Percolation rate in top 12 inches of soil is 3.) mpi percolation Rate R.a.d <br /> Minutes per inch Soil Texture F:;;;;1,. <br /> (mpi) t.e .eea <br /> 2. Select allowable soil loading rate from table; Faster than 0.1 Coarse Sand 1.20 1.00 <br /> . gpd/ft2 0.1 to 5 Sand 1.20 1.00 <br /> 0.1 to 5 Fine Sand"' 0.60 2.00 <br /> 6 to 15 Sandy Loam 0.79 132 <br /> 13. Calculate adsorption width ratio by dividing rock layer 31 to 30 to Silt Loam 0050 2.40 <br /> loading rate of 1.20 gpd/ft2 by allowable soil loading rate; 46 to 60 ClayLoam 0.45 2.67 <br /> 0ai1.20 gpd/ft2i ,4Sgpd/ft2 = . Slower than y <br /> 0.24 <br /> - 5.00 <br /> "Soil having 50%or more of fine or very fine sand. <br /> 4. Multiply adsorption width ratio by rock layer width to get <br /> required adsorption width; <br /> 2„v x 10 ft= ac,.7 ft <br />