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E-20 <br />MOUND DESIGN PROCEDURE (Continued) <br />(For Flows up to 1200 gpd) <br />G.3. Calculate basal width ratio <br />by dividing rock layer <br />loading rate of 1.20 gpd/ft^ <br />by allowable soil loading <br />rate; <br />1.20 gpd/ft* <br />Check this value on page E-16. <br />4. Multiply basal width ratio by <br />rock layer width to get <br />required basal width; <br />2/0 X iO ft - 2 Q ft <br />H. Downslope Dike Width <br />1. If landslope is 3Z or more, <br />subtract rock layer width <br />from basal width to obtain <br />minimum downslope dike toe width <br />_ _^ft -_ _ft - _ _^ft <br />2. Calculate mound height at edge <br />of rock layer on downslope side; <br />a. Determine depth of clean sand <br />fill at upslope edge of rock <br />layer: / feet <br />b. Multiply rock layer width by <br />landslope to determine drop <br />in elevation; <br />X 2 X \ 100 - ^>^ft <br />c. Add drop in elevation to depth <br />of clean sand at upslope edge <br />of rock layer to get depth of <br />clean sand at downslope edge • <br />of rock layer. <br />OX ft + / ft - ft <br />d. Add depth of clean sand at down- <br />slope edge to depth of rock <br />layer to depth of soil backfill <br />to get mound height at downslope <br />edge of rock layer; <br />jX ft -K^75ft +/^ft - ?Xit <br />e. Enter table on page E-18 with <br />landslope and downslope dike <br />ratio. Select dike multiplier <br />of 3* /9_ _ _• Jit <br />H.2.f. Multiply dike multiplier by <br />downslope mound height to get <br />downslope dike width; <br />3. n X 3X - /^. 2 ft <br />g. Compare the values of step H.l <br />and step H.2.f. Select the <br />greater of the two values as <br />the downslope dike width; <br /> ^feet <br />h. Calculate upslope dike width <br />using upslope mound height <br />and upslope dike multiplier <br />from page E-18; <br />- - -X_ _ _ _ - - - - - - <br />1. Total mound width is the sum <br />of upslope dike width plus rock <br />layer width plus downslope dike <br />width; <br />_ _^ft +_ _ft +_ _ft - _ _ft <br />3. If landslope is 2.9 percent or <br />less, basal width includes both <br />the upslope and downslope dike <br />widths. <br />a. Calculate downslope dike width <br />using steps H.2.a. through <br />H.2.f; /^: Z feet <br />b. Calculate upslope dike width 3 X <br />using upslope mound height and <br />dike multiplier from Page E-18; <br />y.o xT^ft - 3.5 lx. <br />c. Add downslope dike width to <br />upslope dike width to rock <br />layer width to get total mound <br />wid th; <br />/a,z ft -I-/.5ft ^ io ft •Tyjit <br />d. Compare total mound width to <br />required basal width from step <br />G.A. If total mound width is <br />greater than required basal <br />width, use calculated dike <br />widths. If required basal <br />width Is greater than total <br />mound width, increase downslope <br />dike width. ^ —(■nf If. 7