Typical Annual and Snowmelt Urban Stormwater Quality Characteristics
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| Constituent (concentrations reported in mg/L) | Annual | Twin Cities Snowbelt4 | |||||
|---|---|---|---|---|---|---|---|
| Twin Cities1 | Marquette MI2 | Madison WI | Storm Sewers | Open Channels | Creeks | NURP5 | |
| Biological OxygConen Demand | 15 | ||||||
| Chemical Oxygen Demand | 169 | 66 | 169 | 82 | 84 | 91 | |
| Total Kjeldahl Nitrogen | 2.62 | 1.50 | 3.52 | 2.36 | 3.99 | 2.35 | |
| Nitrate + Nitrite | 0.53 | 0.37 | 1.04 | 0.89 | 0.65 | 0.96 | |
| Ammonia | 0.2 | ||||||
| Total Phosphorus | 0.58 | 0.29 | 0.66 | 0.7 | 0.56 | 0.54 | 0.46 |
| Dissolved Phosphorus | 0.20 | 0.04 | 0.27 | 0.25 | 0.18 | 0.16 | |
| Chloride3 | 230 | 49 | 116 | ||||
| Total Suspended Solids | 184 | 159 | 262 | 148 | 88 | 64 | |
| Volatile Suspended Solids | 66 | 46 | 15 | ||||
1 Event mean concentrations; Reference: Brezonik and Stadelmann 2002 2 Geometric mean concentrations; Reference: Steuer et al. 1997 3 Geometric mean concentrations; Reference: Waschbusch et al. 1999 4 Reference: Oberts, G. (Met Council). 2000. Influence of Snowmelt Dynamics on Stormwater Runoff Quality. 5 Reference: Median concentrations from more than 2,300 rainfall events monitored across the nation; EPA, 1983