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MOUND DESIGN WORKSHEET <br />(For Flows up to 1200 gpd) <br />A. FLOW <br />Estimated gpd (see pages D-% or 1-3,4,5) <br />or measured gpd. <br />B. SEPTIC TANK LIQUID VOLUMES <br />-2 opo gallons (see Pages C-3 or C-5) <br />C. SOILS (refer to site aluation) <br />1. Depth to restricting layer = /•Z inches <br />2. Depth of percolation tests = /Z inches <br />3. Percolation rate 44- mpi <br />4. Land slope 4 170 <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 />4:�,cv2 gpd x 0.83 sq. ft./gpd =- sq. ft. <br />2. Select width of rock layer (10 feet or less) _ /o ft. <br />3. Length of rock layer = area + width = <br />Soo sq. ft. + ZC7 - ft = 422 ft. <br />E. ROCK VOLUME <br />1. Multiply rock area by rock depth to get cubic feet of rock; <br />Sba sq. ft. x / ft. -,�co cu. ft. <br />2. Divide cu. ft. by 27 cu. ft./cu. yd. to get cubic yards; <br />-9,v cu. ft. + 27 = &&; cu. yd. <br />3. Mu:tiply cubic yards by 1.4 to get weight of rock in tons; <br />i��cu. yd. x 1.4 ton/cu. vd. _ :�, tons. <br />F. ADSORPTION WIDTH <br />1. Percolation rate in top 12 inches of soil is 14 mpi <br />2. Select allowable soil loading rate from table on page E-16; <br />-�� gpd / f 0) <br />3 Calcu:ate adsorption width ratio by dividing rock layer <br />loading rate of 1.20 gpd/ft2 by allowable soil loading rate; <br />1.20 gpd/ft2+ ,sem gpd/ft2 = 2 , 4 c' <br />Check this value on page E-16. <br />4. Multiply adsorption width ratio by rock layer width to get <br />required adsorption width; <br />/x2.dvft= Z4'ft <br />G-19 <br />D-7 <br />C-3 <br />tT•r.0 .t�11R rd.. _ tl..M Ir 71• <br />34.nC t.uM CAP&WKS, M 6410.5 <br />mom <br />1..ur 111 <br />11,1 <br />1— IN/ <br />1111 <br />1— 1111 <br />r <br />•n er �' <br />IN. <br />`s <br />C-3 <br />34.nC t.uM CAP&WKS, M 6410.5 <br />mom <br />1..ur 111 <br />11,1 <br />1— IN/ <br />1111 <br />1— 1111 <br />1.11 <br />• . � / NN <br />IN. <br />Rock Bed <br />...... ... ... . <br />E-16 i <br />�•wr. V.� YM _ r. r..V �1 <br />------------ <br />♦. .._ <br />11. .M •- _ <br />