I have modeled a roof runoff infiltration chamber bed in HydroCad, which had a primary
(6" pvc) outflow of 0.25 cfs for a 25 yr. event, and a 0.36 cfs for the 100 yr.
The 25 yr. total for the site was 0.03 cfs higher than pre development and the
reviewing engineer wants it the same or less to...