North Chicago Wetland Mitigation Project
The Illinois Tollway conducted wetland restoration on a 160-acre site owned by the State of Illinois in North Chicago for the purpose of mitigating environmental impacts associated with improvements to the northern portion of the Tri-State Tollway.
The site is located just south of Buckley Road (Illinois Route 137) between Illinois Route 41 and Illinois Route 43 and east of the Tri-State Tollway (I-94). The location was selected due to the presence of state-protected species as well as remnant portions of high-quality wetlands in need of restoration.
PROJECT SUMMARY
The Illinois Tollway and the Illinois Department of Transportation partnered in 2006 to rehabilitate 150 acres of native landscape in North Chicago. Before the mitigation effort, a layer of invasive shrubs covered the site's native plant species and development was a threat to the site.
Rehabilitation work included clearing brush and other invasive woody vegetation, planting and seeding native species, restoring wetlands followed by years of maintenance and monitoring.
By removing invasive vegetation, native plants within the existing wetlands were allowed to flourish. In addition, surrounding buffer areas were cleared of non-native invasive shrub species and seeded with prairie plants, grasses, sedges and other native species.
To facilitate the wetland restoration, existing agricultural drainage tiles were removed, portions of the site was mowed with heavy equipment and all cut stumps were treated with herbicide. Due to the patchy-ness of the high-quality plants such as Nannyberry shrubs, hand clearing was also needed some areas.
Seed mixes used to overseed cleared areas even included a few rare species such as Great Angelica (angelica atropurpurea) and Great St. John’s Wort (Hypericum ascyron) in the Wet-Mesic Prairie areas.
PURPOSE
The North Chicago Wetland Mitigation site was restored in order to mitigate wetlands that were impacted during the Tri-State Tollway (I-94/I-294) Rebuild & Widen Project, as well as the Illinois Department of Transportation's work on Illinois Route 47.
The project was coordinated with the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the Illinois Department of Transportation, the Illinois Department of Natural Resources, the University of Illinois, Lake County Stormwater Management Commission, the Forest Preserve District of Lake County and the City of North Chicago.