The Illinois Tollway partnered with the Forest Preserve District of Cook County (FPDCC) to implement a stormwater demonstration project along the North Tri-State Tollway in northern Cook County.

Four types of swale were constructed along I-294 in 2010 to help filter pollutants in road runoff:

– Wet Swale with seed mixture 1
– Wet Swale with seed mixture 2
– Dry Swale
– Dry Swale with an under drain pipe

We monitored the vegetation in the 4 types of wetlands beginning in 2011

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Highlights from our work:

  • Desirable wetland species have become established in bioswales; however, invasive species remain among the dominants in approximately half of the bioswales.