Interstate-355 Extension Opens
Illinois State Geological Survey (ISGS) staff members played a large role in the environmental studies for the I-355 tollway south extension from I-55 to I-80, which opened on November 11, 2007. Beginning in 1989, various proposed alignments were evaluated for the potential for hazardous waste, and the results of those studies were used in alignment selection. The studies continued through 2002, when specific parcels to be acquired were assessed for potential environmental hazards in a cooperative agreement between the Illinois Department of Transportation and the Illinois Toll Highway Authority. In addition, significant delays in construction were caused by the presence of the Hines Emerald dragonfly, a federally endangered insect that inhabits seeps along the tollway route in the lower Des Plaines River valley. ISGS has been involved in several phases of habitat planning for the tollway, beginning with an early 1990s study on the impacts on dragonfly habitat from the potential reduction of seep discharge caused by the loss of infiltration from new impermeable roadway surfaces. Routing and design alterations were suggested at that time. ISGS is currently involved in the mitigation of the tollway's impacts on the dragonflies by studying the hydrology and geochemistry of the current dragonfly habitats to help design new dragonfly habitat restoration areas.