Ohio State University Extension Bulletin

Mound Systems for On-site Wastewater Treatment

Siting, Design and Construction in Ohio

Bulletin 813


Mound System Design Example

Step 14. Determine the End Slope Length.

The mound will slope off at both ends. By adding on the end slope length, the overall length of the finished mound can be outlined on the site. Be sure that design specifications require that all trees are removed from this location. If soil is mounded around the base of a tree it will die.

End Slope Length = (Mound side slope factor) * (Average depth of sand fill under absorption area + Aggregate depth + Distribution protection depth + Mound cap depth)

End Slope Length

End Slope Length:

The recommended mound side slope is 3:1 in this design example.

End Slope Length = (Mound side slope factor) * (Average depth of sand fill under absorption area + Aggregate depth +
   Distribution cover depth)
= 3*([22+28]/2 inches + 9 inches + 12 inches)
= 138 inches
= 11.5 ft


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