Slide 12 of 39
Notes:
A variation of the infiltration trench is the dry well which can be effectively used to accept rooftop runoff, as indicated in this schematic. Dry wells can be effective practices at reducing total runoff volume from a site. Note the inherent problem of no pretreatment, depending on the roof surface, this can be either a minor problem or a potential for premature failure (i.e., asphalt shingles contain a sizable solid load that will eventually clog the practice).