CHICAGO - More than 100 years ago, city officials reversed the Chicago River's flow to keep sewage and other filth from spilling into drinking water in Lake Michigan.
To do this, they dug the 28-mile Chicago Sanitary & Ship Canal, a highly lauded engineering accomplishment that connects the Great Lakes to the Illinois River and ultimately to the Mississippi River.
But for environmentalists, the connection of the Great Lakes and Mississippi River basins has been a nightmare, facilitating the spread of invasive species and endangering the ecology of states at both ends of the waterway.
Today, as more and more scientists say the best way to halt invasive species' expansion is to separate the two joined basins - a project that could cost billions of dollars - a group has embarked on a study to examine doing just that.
With $125,000 in funding from the Great Lakes Fishery Trust, Great Lakes Fishery Commission and the U.S.-Canada International Joint Commission, the Chicago-based Alliance for the Great Lakes will spend the next year studying the feasibility of permanently separating the two watersheds.
"We're not saying hydrologic separation is going to occur," said Suzanne Malec, deputy commissioner of the city's Department of Environment. "But it's that extreme a situation that we need to consider everything up to and including that."
By some estimates, the invasive zebra mussel costs the Great Lakes region $1 billion a year in damage and control costs and has made its way downstream to the Mississippi. Moving upstream, the Asian carp jeopardizes the $4.5 billion annual Great Lakes sport and commercial fishing industry. Other species like the round goby, mussels and spiny water fleas also cause financial and ecological headaches.
Basin separation would cost "in the tens of billions," and raise many questions, said Dick Lanyon of the Metropolitan Water Reclamation District.
"No one has pointed their finger at a map and said, 'The (point of separation) goes here,"' he said.
Despite the logistics, the idea is gaining in popularity.
In 2003, "hydrologic separation" was the No. 1 recommendation of nearly 70 scientists, engineers and invasive species experts attending the 2003 Aquatic Invasive Species Summit, convened by Chicago Mayor Richard Daley and the U.S. Fish & Wildlife Service.
Scientists say it's too early to expect a permanent solution and hope the study will facilitate more - and more expensive - research.
"Large-scale feasibility studies for major regional projects could take $20-$30 million," said Chuck Shea, project manager for the U.S. Army Corps of Engineers.