Green Infrastructure Impact on Combined Sewer Overflows
Federal, state, and local governments are all focusing efforts on reducing the destructive impacts of storm water runoff. The major impacts of runoff include pollutant delivery to surface waters, flooding, and erosion. In Illinois, we see evidence of storm water runoff after rainfall events in our yards, streets, fields, streams, and rivers. Green infrastructure is being proposed in many communities to provide relief not only to storm water runoff, but also to combined sewer overflow issues, which several of our local communities are working to resolve.
Central Illinois Conditions
Locally, in the communities of Peoria, Pekin, and Havana, which are served or partially served by combined sewers, the negative impacts of storm water runoff are even more significant. Combined sewers carry both storm water and sanitary sewage in the same pipe. With minimal rain events, the storm water is transported within the sewer pipe to the wastewater treatment plant for proper treatment and discharge to the Illinois River. But, during periods of heavy rainfall, the combined sewer system and treatment plants are not able to handle the storm water runoff, resulting in a combined sewer overflow (CSO) to the Illinois River. These discharges contain water with pollutant levels that violate the Clean Water Act.