Water levels on Lake Michigan are the lowest in recorded history. If the level continues to drop, the Chicago River could reverse itself and send untreated sewage into Lake Michigan.
"We've been monitoring since 1918 and this is the lowest Lake Michigan and Lake Huron have been," Roy Deda, U.S. Army Corps of Engineers, said. "There would be some potential water quality impact to the Great Lakes if we were to continue to lock vessels when the river is higher than the lake."
The Army Corps of Engineers said it is carefully monitoring the situation, and if lake levels continue to drop, they may have to modify how they operate the locks to limit the amount of water that goes into the lake, which would have an impact on recreational boats and barge traffic.
"Regardless of which side is higher or lower, when you open the locks there is an exchange that takes place. When you're talking about Lake Michigan you're talking about a thimbleful of water and pouring it into Lake Michigan," David St. Pierre, Metropolitan Water Reclamation, said.
Beyond water quality, the continued drought conditions and low water levels are having a financial impact the entire great lakes system.
"There is certainly an economic impact to shippers who cannot carry as much cargo in their ships," Deda said.
The Metropolitan Water Reclamation District that manages the region's waterways said it plans to begin disinfecting the waste water that is pumped into the Chicago River, which could take years to implement.