Stormwater Filtration Demonstration Project
MGE's stormwater filtration system, installed as a demonstration project in 2003, has proven to be highly effective. The U.S. Geological Survey monitored and found the system reduced the following pollutants:
- Petroleum compounds by 48%
- Sediment by 39%
- Phosphorus by 36%
- Solids by 32%
- Copper by 23%
- Zinc by 8%
MGE installed this innovative stormwater filtration system in a one-acre parking lot used by MGE and State of Wisconsin employees in downtown Madison. One of the first installations of its kind in Wisconsin, the system:
- Filters out many contaminants that normally run off paved surfaces during rainstorms.
- Helps reduce toxins that degrade water quality.
- Reduces nutrients that promote weed and algae growth in our lakes and rivers.
This best management practice system uses replaceable cartridges within a concrete vault with three compartments:
- A pretreatment bay - where litter and larger sediment particles are trapped.
- A filter bay - where the cartridges filter out smaller pollutants.
- An outlet bay - where the treated flow is collected for discharge through the outlet pipe.

MGE's partners in this demonstration project include:
- Earth Tech, an engineering firm.
- Stormwater Management Inc., a manufacturer of stormwater filters.
- The U.S. Geological Survey.
- The U.S. Forest Products Research Lab.
- Wisconsin Department of Transportation.
- Wisconsin Department of Natural Resources.
For more information
MGE Stormwater Filtration Demonstration Project [205 kB PDF]
Project results from the Wisconsin Water Science Center.
For more information about this technology, visit Stormwater Management Inc.

