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 [PDF - 97 KB]

Project results will be available at the end of 2008 at the Wisconsin Water Science Center Web site.

For more information about this technology, visit Stormwater Management Inc.