Stormwater management principles, detention vs. retention design, low-impact development and green infrastructure practices, and NPDES stormwater permitting basics.
Development changes a site's hydrology in two ways at once — more runoff, arriving faster — and modern stormwater practice is built to manage both the resulting flood risk and the pollutant load that runoff carries. This module covers the two structural approaches to that problem, detention for peak-flow attenuation and retention for water quality treatment, the low-impact development practices that manage runoff at its source instead of only at the bottom of a site, and the NPDES permitting framework that makes most of this legally required rather than optional.
By the end of this module you should be able to explain why detention and retention basins solve genuinely different problems, and why construction-phase erosion control and post-construction stormwater control are two separate regulatory obligations rather than one — a distinction this program's regulations module (Module 13) returns to in more depth.