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• , .��r:7 O,%�l,J�'�',(% � U''Fl.I�'.��.�c 1 E-20 MOUND DESIGN PROCEDURE (Continued) (For Flows up to 1200 gpd) G.3. Calculate basal width ratio H.2.f, riultiply dike multiplier by by dividing rock layer downslope mound height to get loading rate of 1.20 gpd/ft2 downslope dike width; / by allowable soil loading ,3. �p x.�? 6 = /� 2 f t `� rate; 2 / g. Compare the values of step H.l 1. 20 gpdi f t� -0, ,Sgpui i t = 2. �OJ and step H.2,f. Select the Check this value on page E-16, greater of the two values as 4. Multiply b�sal width ratio by the downslope dike width; / rock layer width to get /� � feet `� Y req�iired basal width; h. Calculate upslope dike width .�. �d0 x /O f t =Zi/•D f t � using upslope mound height and upslope dike multiplier H. Downslope Dike Width fro,�-n��pa�e E-18; 1. If landslo e is 3% or more, �. -�r x .-�•U = �f t P i. Total mound widtti is the sum subtract rock layer width of upslope dike width plus rock from basal width to obtain layer width plus downslope dike minimum downslope dike toe wid,th width• / I' ,-�Q �.�j f t - �_f t =/5! Of t ✓ ;�7`. 6f t�+ /O f t +� .�f t =.3'/,4'f t J � S,��r 2. Calculate mound hei ht at ed e � ` g � 3. If landslope is 2.9 percent or �1� of rock layer on downslope side; less, basal width includes both a. Determine depth of clean sand the upslope and downslope dike fi11 at upslope edge of rock / widths. layer: /, O feet `� b. rfultiply rock layer width by a. Calculate downslope dike width landslope to determine drop using steps H.2.a. throup,h in elevation; ` H.2.f; feet - � x �% : 100 = Q, t�f t � b. Calculate upslope dike width c. Add drop in elevation to depth using upslope mound height and of clean sand at upslope ed�e dike multiplier from Pa�e E-18; of rock layer to get depth of a ft = ft clean sand at downslope edge � c. Add downslope dike width to of rock layer. � upslope dike width to rock Q� �ft + /. lJft = /r, �� ft layer width to get total P,101111C� d. Add depth of clean sand at down- width; slope edge to deptti of rock _f t + _ _f t + _f t = f t layer to depth of soil backfill to get mound height at downslope d. Compare total mound width to ed�e of rock layer; / required basal width from step � �ft +,7Sft +/.ZSft =�. li ft � G.4 . If total mound widtli is greater than required basal e. Enter table on page E-18 with width, use calculated dike landslope and downslope dike `! widths. If required basal ratio. Select dike multiplier J width is p,reater than total of -3. 66 3;/ S"ea/>�' mound width, increase downslope dike width.