The report, Re-Envisioning the Chicago River: Adopting Comprehensive Regional Solutions to the Invasive Species Crisis, studies the impact a separation would have in the complicated Chicago Area Waterway System (CAWS). It builds upon previous studies of potential separation sites in the CAWS and draws from a variety of city, state and federal data sources. The study was prepared with engineers from Shaw Environmental in partnership with NRDC with input from City, State, and Federal agency stakeholders. It is presented as the first big step in an iterative process to find a solution to the invasive species and Chicago River issues and is meant to inform the broader public discourse.
In analyzing the local hydrology, the Shaw engineers determined that any rainfall over 0.67 inches would cause flooding and water quality problems due to infrastructure limitations. Shaw then evaluated possible separation sites based on their potential to rebuff invasive species as well as minimize storm impacts, focus investment in water quality improvements, leave recreational boat traffic largely unaffected, and spur the use of green infrastructure to help address the sewer capacity issues while bringing significant aesthetic and functional benefits to neighborhoods. Shaw's green infrastructure modeling showed that planting trees, bioswales and installing rain gardens or rain barrels could lead to substantial reduction in stormwater loads to the CAWS.
The report recommends barriers be placed at the Racine Pumping station on Bubbly Creek near the Bridgeport neighborhood and at the Calumet Wastewater Treatment Facility on the Cal-Sag Channel on the City's far southeast side. The report notes that separation would likely spur other positive outcomes, including fewer flooded basements and a cleaner river. NRDC believes it would also spur significant infrastructure investment. Coincidentally, this week, the Illinois Pollution Control Board is holding the final hearings in their historically-long proceedings on the decontamination of the Chicago River which could also force significant changes to the way the wastewater that makes up most of the river's flow is managed.
One significant concern raised in the report is the potential impact that the barrier placement could have on navigation. Recreational boats will be largely unaffected by the barrier locations. Subsequent studies will have to look more closely at the movement of goods on the CAWS as the barrier in the Cal-Sag channel could limit some barge traffic. However, the report notes that this could lead to the development of a new intermodal facility that would better tie the waterways to the region's rich transportation infrastructure. Only 1% of goods moving through the Chicago area move through the CAWS. Better integration with roads and rails could actually spur commerce on the river.
In a related matter, the Indiana Department of Natural Resources (IDNR) issued a release regarding the construction of a 1,177-foot main fence and a supplemental 494-foot debris catch fence that began in early September and was completed on Tuesday (October 19). The IDNR took a lead role in the fence project after identifying Eagle Marsh as a potential pathway for Asian carp to move from the Wabash River system into the Maumee River, a tributary to Lake Erie. Although the Wabash and Maumee basins drain in opposite directions and have no direct connection under normal conditions, their waters do comingle under certain flood conditions in Eagle Marsh, a 705-acre restored wetland near Fort Wayne.
Access a release from NRDC (click here). Access the 6-page briefing document (click here). Access an NRDC website on the report (click here). Access a release from IDNR (click here).