Detention vs. Retention
Structural Best Management Practices employ two distinct approaches: Detention and Retention:
Why is this distinction significant? Historically, detention technologies have prevailed in storm water management. As we approach higher levels of population density and hence higher degrees of impervious surface coverage, we find that these technologies are not sufficient to manage stormwater.
To effectively offset the impervious surface stormwater contributions we can employ retention methods in which s stormwater can be filtered on-site, back into the ground, rather than contributing to downstream impacts.
If we can achieve zero stormwater runoff through appropriate design, we can lessen the burden on downstream neighbors, ecologies and receiving waters.