Green roofs occur at the beginning of stormwater treatment trains. Green roofs provide filtering of suspended solids and pollutants associated with those solids, although total suspended solid (TSS) concentrations from traditional roofs are generally low. Green roofs provide both volume and rate control, thus decreasing the stormwater volume being delivered to downstream Best Management Practices (BMPs). Green roofs can be particularly effective stormwater Best Management Practices in ultra-urban settings.
For a literature review of green roof benefits, see File:Green roof benefits.docx.