Amended soils disconnection manages runoff close to the source, preventing impervious surfaces from discharging directly to the sewer system by directing the runoff to compost amended soils.
The amended soils provide a “sponge” for absorbing water that is then infiltrated, evaporated, and transpirated in turf areas. This practice is effective not only in reducing runoff but can also be designed as a stand-alone water quality BMP if capable of capturing and treating the required water quality volume, removing required 80% of total suspended solids and having an acceptable longevity rate in the field. Amended soils provide volume reduction, water quality treatment, channel protection storage as reduction in channel protection volume due to change in curve number, peak flood detention storage as reduction of flood protection volume due to change in curve number.
See GRG Levels of Care document.
When amending soils, care should be given to the depth of amendments.