Stormwater Bmp Sizing: green_roof
Stormwater Best Management Practice (BMP) and green infrastructure sizing criteria, pollutant removal efficiencies, and design parameters for 12 BMP types per EPA, International Stormwater BMP Database 2020, MDE, Virginia DEQ, and Minnesota Stormwater Manual
| bmp type | bmp variant | TSS removal pct (%) | applicable HSG | design storm in (in) | expected lifespan years (years) | maintenance frequency | max contributing drainage acres (acres) | media depth in (in) | nitrogen removal pct (%) | notes | peak flow reduction pct (%) | phosphorus removal pct (%) | ponding depth in (in) | relative cost index | sizing ratio bmp to drainage area (dimensionless) | underdrain required | volume reduction pct (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| green_roof | extensive | 85 | A,B,C,D | 0.5 | 30 | twice_yearly | 0.5 | 4 | 30 | Extensive green roof: 4 in growing media. WQv design storm 0.5 in. Volume reduction 50-60% annually. TSS 85% (Minnesota Stormwater Manual 2022). No phosphorus credit due to potential export. Nitrogen TN 30%. | 50 | 0 | 2 | high | 1 | no | 50 |
| green_roof | intensive | 85 | A,B,C,D | 1 | 40 | twice_yearly | 0.5 | 12 | 30 | Intensive green roof: 8-12 in growing media. Larger volume retention. TSS 85%, TP 15% with controlled media P content. Higher structural load. | 65 | 15 | 4 | very_high | 1 | no | 55 |
| green_roof | semi_intensive | 85 | A,B,C,D | 0.75 | 35 | twice_yearly | 0.5 | 6 | 30 | Semi-intensive green roof: 6 in media depth. Moderate structural loading. Performance between extensive and intensive types. | 55 | 10 | 3 | high | 1 | no | 50 |
This is a sample. Search the full stormwater bmp sizing dataset and 300+ more by creating a free account and accessing the database.
Get started for FREE