Study: High Lake Michigan levels could cause issues downstream

[June 08, 2022]  By Scot Bertram | The Center Square contributor

(The Center Square) – High water levels in Lake Michigan could lead to trouble for other Illinois waterways.

A new study from researchers at the University of Illinois Urbana-Champaign focused on how high lake levels influence the bidirectional flow of the Chicago-area waterway system and its connection to the Mississippi River basin.

“There has been a lot of concern in the last few years regarding the invasive species, in particular Asian carp, that have been advancing along the Illinois River,” said Marcelo Garcia, civil and environmental engineering professor at UIUC. “But we haven't really been concerned about what could go from the Great Lakes in a different direction.”

The study shows when Lake Michigan’s level is just 1.5 feet above normal, flow into the Grand Calumet River reverses and drains west toward the Mississippi.

“Depending on what the lake is doing, a certain amount of water is going to come and that water is going to bring different things with it,” Garcia said. “It's going to bring Lake Michigan water, but also could bring up some species that right now we don't find in the Illinois River or the Mississippi River basin.”

In 2020, Lake Michigan reached its highest water level in 120 years. More recently, in April, the lake was 18 inches above the long-term average for the month.

“There could be things like the sea lamprey coming, which we know is in the Great Lakes,” Garcia said. “Well, what if that gets into the system? We have no way of controlling that.”
 

Sea lampreys are parasitic fish, sucking the blood and body fluids of other fish. According to the Great Lakes Fishery Commission, sea lampreys act as predators, with each individual lamprey capable of killing up to 40 pounds of fish over their 12-18 month feeding period.

The problem could eventually necessitate taxpayer funds to address the flow.

“We need some type of control on the Grand Calumet River,” Garcia said. “We don't have anything controlling this leakage basically, or this inflow from Lake Michigan. We don't really know what could be coming from the lake and all that area that the flow picks up.”

Gracia says another problem has to do with the dynamics of nutrients.

“When water flows from the lake towards Illinois, it picks up the effluent from wastewater treatment plants, which most likely have nutrients such as phosphorus in them,” Garcia said. “Such nutrients, coupled with nitrogen used as fertilizer, are contributing to conditions that could potentially lead to algae blooms in the Calumet area.”

The area surrounding the Grand Calumet River has a long history of heavy industry and many local waterways contain some level of chemical pollutants.

“Chicagoland is under the gun due to the nutrients that get discharged at Lockport and end up in the Illinois River and then the Mississippi,” Garcia said. “There are efforts to pin down hypoxia in the Gulf of Mexico to nutrients generated by Chicago.”

Garcia says he doesn’t believe that is the case, but he’s interested in further research to test the hypothesis.