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d"*AeCF BifF.✓ <br />7so coo <br />MOUND DESIGN PROCEDURE <br />k.For Flows up to 1200 gpd) <br />A. Sewage Flow Rate <br />See D-7 or I-3, 4, or 5, or use <br />metered value; Flow Rate = <br />750 gpd <br />B. Septic Tank Liquid Volume <br />(see C-3 or C-5) /250 gallons <br />t ioo o <br />C. Soil Characteristics <br />1. Depth to restricting layer <br />such as seasonally saturated <br />soil, bedrock, coarse soil, <br />etc.; -?0 inches <br />2. Depth of percolation tests; <br />/5 inches <br />3. Number of percolation test <br />holes; holes <br />4. Ave. percolation rate; <br />7 / mp i <br />5. Landslope = S — 6 <br />D. Rock Layer Dimensions- <br />1. Multiply gpd by 0.83 to <br />obtain required area of <br />rock layer; <br />, 73'p gpd x 0. 83 - I!Csq f t <br />2. Select width of rock layer <br />(10 feet or less) = feet <br />3. Length of rock layer - Area <br />= Width 625 sq f t /O f t <br />= 62.5 f t <br />E. Rock Volume <br />1. Multiply rock area by rock depth <br />to get cubic feet of rock; <br />C2 S s q f t x p, 75 f t= J��c u f t <br />2. Divide cu ft by 27 cu ft/cu yd <br />to get cubic yards; / j. $f <br />3. Multiply cubic yards by 1.4 to <br />get weight of rock in tons; <br />17.Y cu yds x 1.4 - ?,V 4/tons <br />E-19 <br />F. Pressure Distribution System <br />1. Select number of perforated <br />laterals 6 <br />2. Select perforation spacing <br />f t <br />3. Select perforated lateral <br />length; Not �f manifcld is <br />at end of rock layer, lateral <br />length is rock layer length <br />less half a perforation <br />spacing. If manifold is in <br />center of rock layer, lateral <br />length is one-half rock layer <br />length less half a perforation <br />spacing. Perforated lateral <br />length = 29.75 f t. <br />4. Divide lateral length by perfor- <br />ation spacing to get nu fiber of <br />perforations per lateral <br />feet . 3 feet = _�perfs <br />Note: last perforation -^ust be <br />in end cap, (see page 4) <br />5. Multiply perforations per <br />lateral by number of laterals <br />to get total number of <br />perforations; <br />,L/—perfs/lat x 6 lats = e4C <br />6. Determine required flow rate <br />by multiplying number of <br />perforations by flow per <br />perforation (see page E-17) <br />46 perEs x ,%YPpm/perf = ,jagpm <br />Select minimum required lateral <br />diameter from table on Page I:-17; <br />enter table with perforation <br />spacing, perforation diameter, <br />and number of perforations per <br />lateral. Select minimum <br />diameter for perforated lateral <br />/ 1/y inches <br />G. Basal Width <br />1. Percolation rate in top 12 <br />inches of soil is 7. / mpi <br />2. Select allowable soil loading <br />rate from table on page E-16; <br />are O. 60 ppd/ft2 <br />