River Renaissance: New Report Details Separation to Keep Carp Out of Great Lakes

Engineering Study Re-Envisions Chicago River Solves Two Problems with One Solution

CHICAGO (October 20, 2010) -- Building two strategically-placed barriers between the Great Lakes and Chicago River could open the door to a revitalized waterway and surrounding communities,  while effectively shutting the door on Asian carp, according to a new report by the Natural Resources Defense Council. This new report investigates a variety of hydrological separation scenarios in order to determine the best way to fix both the Asian Carp crisis and the litany of issues associated with Chicago’s aging water infrastructure through one smart solution.

“The Carp crisis illuminates how unacceptable conditions are   on the Chicago River,” said NRDC Midwest Program Director Henry Henderson, who also served as the City of Chicago’s first Commissioner of the Environment. “It is clear that the public is ready to re-imagine the waterway rather than accept an aging invasive species superhighway and open sewer status quo. We believe this report moves that process forward.”

“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. Green infrastructure is the use of natural systems, such as wetlands, street trees, and other types of vegetation to store and treat stormwater instead of the “hard infrastructure” that is traditionally used, such as pipes, pumps, and storage tunnels.  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.

“The reversal of the Chicago River was important a century ago, but technology and attitudes have evolved over the last 100 years,” said Henderson. “Unfortunately, our methods and means of treating our storm and wastewater have not. You wouldn’t build a road and then leave it sitting for 100 years without upgrading it. It’s time for a river renovation.”

The 70+ page technical document has been summarized into a six-page briefing.

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.