Stormwater Bmp Sizing: swale
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) | infiltration rate in per hr min (in/hr) | 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 (%) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| swale | bioswale | 75 | A,B,C,D | 1 | 20 | 0.5 | twice_yearly | 5 | 18 | 30 | Enhanced dry swale with engineered media. Ponding depth 4-9 in. TSS 75%, TP 35%. Functions similarly to linear bioretention. | 50 | 35 | 6 | medium | 0.01 | optional | 35 |
| swale | dry_grass | 68 | A,B,C,D | 1 | 20 | 0.5 | twice_yearly | 5 | 0 | 20 | Dry swale (grass channel): check dams at 50-100 ft spacing. 10-min residence time design. TSS 68% per Minnesota Stormwater Manual. TP variable. Max velocity 1.5 ft/s in grass channel. | 40 | 20 | 0 | low | 0.01 | no | 20 |
| swale | level_spreader | 60 | A,B | 0.5 | 20 | 0.5 | annually | 2 | 0 | 15 | Level spreader to vegetated filter strip. Converts concentrated flow to sheet flow. TSS 60%. Requires stable outlet. | 35 | 20 | 3 | low | 0.005 | no | 15 |
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