Proposal getting much of the attention involves controlling the carp by returning the flow of the Chicago River to the way it originally was, albeit with some very elaborate safety measures.
Groups representing states and cities in the Great Lakes region on Tuesday proposed spending up to $9.5 billion on a massive engineering project to separate the lakes from the Mississippi River watershed in the Chicago area, describing it as the only sure way to protect both aquatic systems from invasions by destructive species such as Asian carp.
suggesting three alternatives for severing an artificial link between the two drainage basins that was constructed more than a century ago. Scientists say it has already provided a pathway for exotic species and is the likeliest route through which menacing carp could reach the lakes, where they could destabilize food webs and threaten a valuable fishing industry.
"We simply can't afford to risk that,'' said Tim Eder, executive director of the Great Lakes Commission, which sponsored the study with the Great Lakes and St. Lawrence Cities Initiative. "The Great Lakes have suffered immensely because of invasive species. We have to put a stop to this."
While no single government agency has authority to approve or reject the project, federal support would be crucial because the U.S. Army Corps of Engineers oversees shipping locks and other navigation infrastructure in the Chicago waterway system. The federal government undoubtedly would be asked to provide some of the funding.
The report's release is sure to ramp up pressure on the corps, which is conducting its own study of how to close off 18 potential pathways between the two systems, including the Chicago waterways. The corps plans to release its findings in late 2015, a timetable it says is necessary because of the job's complexity and regulatory requirements. A pending federal lawsuit by five states -- Michigan, Wisconsin, Minnesota, Ohio and Pennsylvania -- demands quicker action.
"This study shows that hydrological separation is both technically and economically feasible," said Rep. Dave Camp, a Michigan Republican.
Sen. Debbie Stabenow, a Michigan Democrat, said the report should help build support in Congress for legislation she and Camp are co-sponsoring that would order the corps to finish within 18 months.
A spokeswoman said the corps would not comment until it could review the report.
John Goss, director of the White House Council on Environmental Quality's Asian carp program, said basin separation was one potential solution to the region's invasive species problem. The Obama administration has spent more than $100 million on efforts to stem the carp's advance toward the lakes that include operating an electric barrier near Chicago, monitoring the waterways and researching new technologies.
"We look forward to reviewing the study and assessing how this information can be helpful,'' he said.
The project that linked the two drainage basins began in the 1890s when engineers reversed the flow of the Chicago River to flush sewage away from the city and into a newly built, 28-mile-long canal that created a connection between Lake Michigan and the Illinois River, a tributary of the Mississippi. It is now a network of rivers, locks and canals.
In their report, the two groups call for placing barriers at key points to cut off the flow of water between the two drainage basins by 2029.
One alternative would put barriers in five locations near Lake Michigan. Another would erect a single barrier in the ship canal before it branches off into connecting waterways. A third plan would use four barriers.
The report does not express a preference but says the four-barrier plan would cost less than the others -- between $3.26 billion and $4.27 billion. That plan, the report says, would cause less disruption of waterborne commerce and fewer problems with flood and stormwater control, all of which opponents contend would result from dividing the two systems. It also comes closest to restoring the natural divide between the watersheds, said David Ullrich, executive director of the Great Lakes and St. Lawrence Cities Initiative.
The report doesn't make a detailed proposal for covering the costs but says the four-barrier plan could be done if the average household in the Great Lakes basin paid about $1 a month through 2059.
The five-barrier and single-barrier plans' price tags could reach about $9.5 billion.
Despite the high cost, the report's sponsors said the project would save money in the long run by shielding both systems from species invasions. Zebra and quagga mussels and sea lamprey already have exacted a heavy toll on the Great Lakes economy, and the region's leaders fear the Asian carp could make things much worse.
"Yes, it's expensive. But the cost of doing nothing is greater," Ullrich said.
Asian carp escaped from Southern fish farms and sewage treatment plants decades ago and migrated up the Mississippi and its tributaries, gobbling up plankton that is essential for other nourishing other fish.
The study, commissioned by the two groups and developed by a private engineering firm, will make the idea of separation easier for people in the region to grasp, said Joel Brammeier, president of the Alliance for the Great Lakes, a Chicago-based environmental group.
"It's a natural, practical, on-the-ground map of how to get it done,'' Brammeier said.
Mark Biel, chairman of an Illinois business coalition called UnLock Our Jobs that opposes separating the watersheds, said the Great Lakes groups' proposals would take many years to carry out and would devastate cargo shipping and pleasure boating in the Chicago area while doing nothing to prevent species invasions elsewhere.
"Calling this a solution is ludicrous," Biel said.
But the report's authors said their plan envisions upgrades to docks and other infrastructure that, in the long run, would boost water commerce while improving water quality and flood protection. The barriers themselves would make up just 3 percent of the total cost.
The Army Corps of Engineers contends the electric barrier network in the shipping canal is preventing Asian carp and other fish from swimming upstream toward Lake Michigan, although carp DNA has been found beyond the device. Eder said the barrier is a good temporary measure, but not a permanent solution.
"It's kind of like the old Clint Eastwood adage, 'How lucky do you feel?'" he said. "We can take chances that the electric barrier and other measures will work, but I don't think we should."