CHICAGO (AP) - Waterways engineered more than a century ago to connect the Great Lakes and Mississippi River watersheds should be altered to stop the exchange of invasive species that can cause irreversible damage, an environmental advocacy group says.
A 106-page feasibility study to be released Wednesday by the Alliance for the Great Lakes says separating the watersheds is the only way to stop the transfer of some invasive species, including the voracious Asian carp now within 50 miles of Lake Michigan.
"If you want to protect the Great Lakes, this is what you have to do. Invaders like Asian carp are unpredictable, but their effects are catastrophic and irreversible," said Joel Brammeier, Alliance president and lead author of the study. "You've got to remove their pathway."
The Great Lakes and Mississippi River watersheds aren't connected naturally. Engineers linked them more than a century ago through a complex network of manmade canals and natural rivers to reverse the flow of the Chicago River and keep waste from Lake Michigan, which Chicago uses for drinking water.
Possible changes include erecting concrete walls and constructing more shipping locks in up to six areas, according to the study. It does not make explicit recommendations, but calls on the U.S. Army Corps of Engineers and Environmental Protection Agency to conduct further study.
EPA and Army Corps offices were closed Tuesday, so officials could not be reached for comment.
The study - funded by the Great Lakes Fishery Commission and Great Lakes Fishery Trust - gives only general cost ranges for each project, up to $15 million, and says a multiyear revenue source is needed. It does not say who should pay.
Brammeier said the study was sparked by a 2003 meeting convened by Chicago Mayor Richard Daley and the U.S. Fish & Wildlife Service, where dozens of engineers and experts recommended "hydrologic separation" of the watersheds by 2013.
Since the summit, EPA and Chicago officials have put in place an electrical barrier through the Chicago Sanitary and Ship Canal south of the city to keep Asian carp out of Lake Michigan. The Alliance says the barriers, which deliver a non-lethal jolt to fish, have been effective, but are not a long-term solution.
Researchers fear the fish, which can grow up to 100 pounds and more than 4 feet long, could eat all the food that's available for other species, decimating the Great Lakes ecosystem and possibly leading to the collapse of the multibillion-dollar fishing industry, Brammeier said.
"When invasive species arrive, they can destroy the quality of life for people who depend on those waters," Brammeier said.
Scientists say more than 150 invasive species are living in the Great Lakes, where they multiply rapidly and harm ecosystems by threatening food supplies or feeding on native species.
The zebra mussel and round goby have already been moving between the Great Lakes and Mississippi River basins. Millions of dollars have been spent trying to control them.
The six areas identified in the report are a canal at Lockport and Romeoville, the south branch of the Chicago River, the Chicago Lock to Lake Michigan, the Calumet River, the Grand Calumet River and the Little Calumet River.
Not all areas would have to be dealt with immediately, since further study might narrow the focus to one or two areas, Brammeier said.
The study also examines other barriers such as chemical repellants and lights as well as combinations of some of the technologies.
Researchers admit that there would be changes to navigation if barriers were put in place. For instance, one of the report's suggestions is putting locks on the Calumet River, which hosts heavy barge traffic between Chicago and Indiana. Locks would still enable boats and ships to pass without invasive species getting through.
But any type of barrier would slow traffic and cost money, said Stuart Theis, executive director of the United States Great Lakes Shipping Association. Still, he said, he would cautiously support efforts to separate the watersheds.
"We wouldn't object to efforts that would keep invasive species out of the Great Lakes," he said.
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On the Net:
The Alliance for the Great Lakes: www.greatlakes.org
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