Stormwater Best Management Practices (BMP)

Most planned GRG projects fall within the St. Louis MSD services territory. St. Louis MSD’s MS4 Permit includes 60 cities, villages and towns as co-permitees. If trail projects disturb over an acre, post construction stormwater BMPs must be put into place that mimic predevelopment conditions. BMPs must treat a water quality volume from 1.14 inches of rainfall and BMPs must be located outside of the 100-year floodplain. Additionally, channel protection detention is required for the 1-year, 24-hour rainfall event.

In the image above, a sunken bioretention cell manages stormwater runoff from the adjacent roadway and sidewalk.

A variety of post-construction BMP types are approved by St. Louis MSD, and the most applicable BMP types for use within the GRG system are listed below. Additional detail information is included in the links below: