If you walked along Chicago’s Riverwalk this weekend – no your eyes were not playing tricks on you. The Chicago River took on two distinct colors – one of them looking very unnatural. At Wolf Point – the normally dark, muddy color of the north and south branches of the river was met by the vibrant teal – closely resembling the green hue pumped in for the city’s annual St. Patrick’s Day river dyeing or the waters of Canada’s Lake Louise.
The sight became apparent on Friday and lingered into Sunday – people downtown in high rises saw it more clearly than at street level Officials with the city’s Department of Water Management and the Metropolitan Water Reclamation District of Greater Chicago have been investigating.
“The DWM and the MWRD went out to investigate this area this morning,” said Megan Vidis, water department spokeswoman on Sunday. “The discoloration is not due to outfill, but caused by a combination of the storm, seasonal vegetation changes and other naturally occurring circumstances.
“We will continue running tests on the water in the impacted areas to monitor the situation.”
The head of one environmental group was skeptical that the flow of sewage into the river wasn’t at least partly to blame. But she said that she’d defer to City Hall’s explanation for now.
“We’ll have to see what the tests reveal,” said director of Friends of the Chicago River, Margaret Frisbie.
According to Frisbie, heavy rainfall like the kind that fell on Saturday morning can overwhelm sewers, with the overflow escaping through “outfalls” — giant tubes that carry the excess stormwater and sewage into the river.
“Sadly, when it rains we get a lot of sewer drainage in the river,” Frisbie said. “It’s not good, it’s harmful to the fish and to people’s health.”
According to the National Weather Service, close to a half-inch of rain was recorded at O’Hare Airport on Saturday, with more falling Sunday. The river’s coloring capped off a troubling week for the city’s waterway. Crews are still trying to locate the source of an oil spill that slicked the Bubbly Creek portion of the river on the South Side on Oct. 26.
The heavy rainfall can be known to cause a lot of trouble for the river – just last month the river overflowed onto its scenic walkways after a rainstorm – causing police to tape off several entryways from Franklin Street east to the lake.