Congress ordered the Army Corps of Engineers to find a way to prevent aquatic invasive species from passing from the Mississippi River to the Great Lakes Basin, and the reverse.
For years, officials have feared that Asian carp would make their way from the Mississippi system into Lake Michigan. There has been more than one scare. Three months ago, a live Asian carp was caught after making its way through a system of underwater electric barriers nine miles from Lake Michigan.
David Hamilton with The Nature Conservancy’s Great Lakes Project says Asian carp just happen to be the poster creature of the problem. Both the Great Lakes and Mississippi basins are at risk of invasion from nonnative species migrating from one basin to the other.
In 2014, the Army Corps of Engineers released a report exploring possible solutions in the entire Chicago Area Waterways System, or CAWS. It connects the Great Lakes and the Mississippi River basins.
The Corps decided to focus on the Brandon Road lock in Joliet, Illinois.
“Anything that is going to float, swim or be attached to a vessel from the Mississippi toward the Great Lakes has to pass through that lock," Hamilton says. "So it’s a critical point. So if effective measures are put in there, then we can stop invasive species.," he says.
The Army Corps whittled their six strategies down to one recommendation, called the Technology Alternative:
Complex Noise with Electric Barrier, which includes the following measures: nonstructural measures, complex noise, water jets, engineered channel, electric barrier, flushing lock, boat launches and mooring area. The goal will be to optimize alternative effectiveness while minimizing safety impacts.
David Hamilton says The Nature Conservancy, or TNC, agrees that a “defense in layers” strategy is good, but says something is missing. “When the Corps describes what it’s going to be effective against, it doesn’t include animals that are attached to the vessels and it may or may not be completely effective against fish, especially small fish."
TNC commissioned a U.S. Geological Survey study that Hamilton says identified treatment measures that could be 100% effective in a treatment chamber.
“The vessel would come into the treatment chamber, the gates would be closed and them a chemical (chlorine) would be used to kill any species that are in there," Hamilton explains. "That would be neutralized and then the vessel could continue into the lock and move on upstream."
He says the treatment chamber would eliminate the need of the electrical barrier at Brandon Road, which is the most expensive element of the Army Corps $275 million recommended plan. "The barrier and associated infrastructure would cost $161 million, our engineer who designed the treatment system said it would cost $43 million."
Hamilton says The Nature Conservancy hopes to convince the Army Corps to modify its plan.
“I have talked with Corps of Engineers one-on-one and they can see this has potential," he says. "I still have great hope that they will pick it up and pursue it."
The public has until November 16 to weigh in on the Army Corps proposed solution.
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