The potential trouble lurking in the Chicago River system is bigger than just the giant Asian carp, according to a new report from the U.S. Army Corps of Engineers.

The agency has identified 40 "high-risk" species that could use the canal system to invade vast swaths of the continent, ranging from fish to crustaceans to mollusks to plants.

The canal system is so critical to the dispersal of unwanted species across North America because it destroyed the natural divide that separated the waters of the Mississippi River basin from the waters of the Great Lakes when it opened more than 110 years ago.

The report is part of the Army Corps' ongoing study looking at what it will take to re-create the natural barrier between the two basins that the Chicago canal system destroyed. The study is also looking at other potential breaches between the historically separated basins.

While the immediate fear is the danger Asian carp pose to Lake Michigan and the rest of the Great Lakes, the agency's newly released 35-page "white paper" makes it clear that the problem is much bigger than that.

The point of the paper, according to the Army Corps' Gary O'Keefe, is to help his agency focus on technology to keep unwanted species from spilling between the two basins.

Many environmental groups and politicians outside Illinois, however, believe the best technology has already been identified - a physical separation of the two basins with some sort of barrier. That is something the Army Corps is evaluating, but the agency also is looking at other types of barriers that could allow water and commerce - but not species - to continue to flow between the basins.

Pro-business groups worried about how plugging the canal system could affect navigation and the industries that rely upon it took a completely different tack after the release of the Army Corps report.

"While many will surely jump on this report as justification for permanent separation of the two watersheds, its true implication is exactly the opposite," said Lisa Frede, director of regulatory affairs for the Chemical Industry Council of Illinois. "Permanent separation is not feasible for at least 50 to 75 years, if it's possible at all ... We need to be looking at a variety of solutions to address varying species with different ecological profiles that can be achieved in the near term."

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