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: <br />rri'':- <br />E-20 ■ r • i <br />■■ . .■ <br />tFV '> ■ <br />MOUND DESIGN PROCEDURE (Continued) <br />(For Flows up to 1200 gpd) <br />'••■X <br />:0 <br />?? <br />i- <br />hr <br />1-^ <br />f- ’ ;• <br />c.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/ft2 "^.%pu/f ° 2MC <br />Check this value on page E-16. <br />11.2,f. Multiply dike multiplier by <br />downslope mound lieight to g . <br />down slope dike v/idth; y <br />-57 96' X >’. 7 * la. ^ f t <br />R <br />U, Multiply basal width ratio by <br />rock layer width to get <br />required basal width; <br />:< iO ft - Vi±iri <br />Compare the values of step I!. I <br />ajid step Select the <br />greater of the two values as <br />the downslope dike widtli; <br />?0, 6 feet <br />m <br />H <br />k <br />H.Downslope Dike Width <br />1. <br />»V'; <br />■' ':.c' <br />; ■ <br />If landslope is 3Z or more, <br />subtract rock layer width <br />from basal width to obtain <br />minimum downslope dike toe width <br />2y.<P ft - ft - /y.^ 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 upslopc edge of rock <br />layer: / feet <br />b. Multiply rock layer width by <br />h. Calculate upslopc dike width <br />using upslope mound height <br />and upslope dike multiplier y <br />^from pagc.^E-lB; c>. yft <br />i. Total mound width is the sum <br />of upslopc dike v/idth plus rock <br />layer width plus downslope dike- <br />width; y <br />■?,‘f ft + A* ft +.’<^.6'ft » VO ft y <br />. .1 <br />■ <br />.r <br />3.If landslope is 2.') percent or <br />less, basal width includes both <br />the upslope and downslope dike <br />widths. <br />■f. <br />landslope to determine drop <br />in elevation; <br />/O X “7 X - 100 •Os / ft <br />a. Calculate downslope dike wid <br />using stops n.2.a. through <br />H.2.f; _ _ _ _ _ _ _feet <br />6 ’c.Add drop in elevation to depth <br />of clean sand at upslcpc edge <br />of rock layer to get depth of <br />clean sand at downslope edge . <br />of rock layer. <br />g, /ft + / ft “ Ay ft <br />d. Add depth of clean sand at down- <br />slope edge to depth of reck <br />layer to depth of soil backfill <br />to get mourd height at downslope <br />edge of rock layer; <br />b. Calculate upslopc dike width <br />using upslopc mound height and <br />dike multiplier from Page E-18; <br />f t = ft <br />■■-■'I <br />X <br />c. Add downslope dike width to <br />upslope dike width to rock <br />layer width to get total mound <br />width; <br />ft + ft ft » ft <br />".'i- ■ <br />■■ <br />uTM . <br />/.V ft d-.7^ft + /.^^ft - 7Jt <br />e. Enter table on page E-18 with <br />landslope and downslope dike <br />ratio. Select dike multiplier <br />of jsr. y.v r- <br />/ <br />d. Compare total mound width to <br />required basal width from step <br />G.4. If total round width is <br />greater than requivt-d basal <br />wid*"!!, use calculated dike <br />widths. If required basal <br />width is greater than total <br />mound width, Incroaeo downolopu <br />dike width. <br />m m <br />.'i <br />•:oVi <br />-'M