Asian carp should be permanently cut off from Lake Michigan by sheet pile or impermeable land bridges, effectively re-reversing the flow of the Chicago River, according to a study set to be released Tuesday by a coalition of Great Lakes states and cities.
The study, which was put together by the Great Lakes Commission and Great Lakes St. Lawrence Cities Initiative, comes amid concerns that ongoing efforts to stop the influx of Asian carp in Illinois may not be reliable or financially sustainable. Although an electric barrier currently runs across the Chicago Sanitary and Ship Canal near Lockport, recent tests have suggested that it might not be effective for small fish.
Asian carp are only the latest invasive group to assail the Chicago-area waterways, following devastating species such as zebra mussels and round gobies.
For years, the idea of closing the area's navigational locks has been highly controversial, pitting groups who believe it is the only way to prevent the fish from destroying the Great Lakes ecosystem against others who contest it will decimate Chicago's cargo shipping and tour boating industries.
The Great Lakes Commission and Great Lakes St. Lawrence Cities Initiative's study details three options to permanently separate the Chicago-area waterways from Lake Michigan over the next 50 years and estimates costs.
"The big thing is that it is feasible, it is very doable and I think the costs are reasonable," said Tim Eder, executive director of the Great Lakes Commission.
In the "Near Lake" option, five barriers would be established in rivers close to Lake Michigan, stretching from the North Side waste water treatment plant to the Little Calumet River. It would close the downtown navigational lock that has been one of the focal points of an ongoing legal dispute between the Great Lakes states and would cost about $9.54 billion.
The next most costly option would be the "Down River" plan, which would set up a single barrier at the confluence of the Chicago Sanitary and Ship Canal and the Calumet Sag Channel just north of the electric barrier. It is estimated to cost about $9.5 billion.
The third and least costly option would be the "Mid System" approach, which would establish four barriers, including one just north of the T.J. O'Brien Lock and Dam near Lake Calumet. It would be turned into a transfer point that would allow the exchange of goods, people or boats from the river to trains, trucks and other boats bound for Lake Michigan.
The "Mid System" approach would cost about $4.27 billion and would pose "the fewest challenges for storm water management, flood management, water quality and transportation," the study stated.
"It has some big advantages over the other two," Eder said.
The plans propose a roll out in multiple stages over the next several decades. By comparison, the study states that $50 million is now being devoted annually to Asian carp control, management, research and prevention.
"Without a long-term solution, the costs for Asian carp will continue indefinitely and the door will be left open for new invasive species," the study notes.
The study's authors are now reaching out to federal and local lawmakers to discuss the plans and what may be feasible moving forward. They have also shared their data with the Army Corps of Engineers, which is working on a much larger, long-term study that also explores permanent separation.
Explore further: Efforts to close canal to Great Lakes