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E-20 <br />"f. <br />MOUND DESIGN PROCEDURE (ConCinued) <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 />rates <br />1.20 gpd/ft2 rAS gpd/f t^ - <br />Check this value on page E-16. <br />H.2.f. Multiply dike multiplier by <br />downslope mound height to get <br />downslope dike width; <br />S.so X - /7.5^ft <br />4. Multiply basal width ratio by <br />rock layer width to get <br />required basal width; <br />^ - 2j^.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 />2V ft - a: ft - /yft <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: /. O feet <br />b. Multiply rock layer width by <br />landslope to determine drop <br />in elevation; <br />X St - 100 - ' <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 />O.Slt + /.gft - /.5 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 />A^ft -f A^ft -f 40ft •S.S It <br />Enter table on page E-18 with <br />landslcpe and downslope dike <br />ratio. Select dike multiplier <br />of s. oo Y: / <br />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 />/7. S feet <br />h. Calculate upslope dike width <br />using upslope mound height <br />and upslope dike multiplier <br />i. Total mound width is the sum <br />of upslope dike width plus rock <br />layer width plus downslope dike <br />width; <br />/a-Oit + /J ft -K/7.51ft «J^A5Tft <br />3.If landslope is 2.9 percent or <br />less, basal width includes both <br />the upslope and downslope dike <br />widths. <br />Calculate downslope dike width <br />using steps H.2.a. through <br />H.2.f; _ _ _ _ _ _^feet <br />b. Calculate upslope dike width <br />using upslope mound height and <br />dike multiplier from Page E-16; <br />_ _X_ _ _ft -_ _ _ft <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 />d. Compare total mound width to <br />required basal width from step <br />C.4. 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.