Laserfiche WebLink
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/ft2 <br />by allowable soil loading <br />rate; <br />1.20 gpd/ft2 ='.Y✓`'gpd/ft2 =? 67 <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 />2,67 Y /c, ft =26.7ft <br />• <br />H. Do%.mslope Dike Width <br />1. If landslope is 3% or more, <br />subtract rock layer width <br />from basal width to obtain <br />minimum downslope dike toe width <br />2C. Zfc - loft -/6.7ft <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 />/Ox 7`/.=1000.7ft <br />c. Add drop in elevation to depth <br />of clean sand at upslope edge <br />of rock layer to get depth of <br />r.lean sand at downslope edge <br />of rock layer. <br />0.7 ft + _/ft = /- i `t <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 />/. 7 ft +0.75ft +/,2Sft j_ft <br />e. Enter table on page E-18 with <br />landslope and downslope dike <br />ratio. Select dike multiplier <br />of jr. S.6 y: / rloof <br />E-20 <br />11.2.f. Multiply dike multiplier by <br />downslope mound height to get <br />downslope dike width; <br />5-56x -7.7 a20.6ft <br />g. Compare the values of step 11.1 <br />and step 11.2.f. Select the <br />greater of the two values as <br />the downslope dike width; <br />20. 6 feet <br />h. Calculate upslope dike width <br />using; upslope mound height <br />and upslope dike multiplier <br />. %2 p.x _ E-18 f t <br />i. Total mound width is the sum <br />of upslope duce width plus rock <br />layer width plus downslope dike <br />width; <br />9_�ft + /0 ft +2'r ft ft <br />3. If landslope is 2.9 percent or <br />less, basal width ?.--ludes both <br />the upslope and :.)pe dike <br />widths. <br />a. Calculate downslope dike width <br />using steps 11.2.a. through <br />It. 2.f; feet <br />b. Calculate upslope dike width <br />using upslope mound height and <br />dike multiplier from Page E-18; <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 />G.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. <br />