Reversal of Chicago River likely helped lead to swimming bans at beaches
CHICAGO (CBS) – Many in Chicago were still reeling from Sunday's significant rainfall after storms shut down the Riverwalk and many public beaches.
CBS's Lauren Victory explained how a decision to reverse the Chicago River's flow led to water quality issues at local beaches.
Swimming was banned at all Chicago beaches for several hours on Monday. It's likely that a decision to send the river water into Lake Michigan contributed to unsafe conditions.
The teams inside the Metropolitan Water Reclamation District said they had no choice but to reverse the river to prevent further flooding.
It's a decision they haven't had to make since May 2020. The tunnels and reservoirs the crews manage were filling up with storm and sewage water and the rain wasn't letting up.
That led the Chicago River to rise rapidly.
"Worse than the amount of rain is the quick time period in which it fell," said Ed Staudacher, assistant director of maintenance operations at the Metropolitan Water Reclamation District.
Walkways were underwater and other sections of the Riverwalk were submerged on Sunday. Down below, stormwater combined with sewer water overwhelmed pipes.
Staudacher said once the sewers fill, water goes over into the deep tunnel system, fills those tunnels, and runs into reservoirs. Sunday's storm brought the water in those reservoirs to capacity.
The district gave the green light to open the lock and the gates near Navy Pier around 2:30 p.m., something Staudacher said the agency rarely does.
The river then poured into the lake for about seven hours. Red flags warned Chicago beachgoers of a swimming ban after water quality issues cropped up. E. coli levels were likely affected by the river reversal.
"By that point in the storm, most of it is going to be rain water coming," Staudacher said. "So much rain is coming down. It's very dilute."
But why was this such a big deal?
"Our drinking water comes from Lake Michigan," said Staudacher. "So the reason why the river was reversed originally was to keep the water, sewage, runoff, keep everything out of Lake Michigan so we're trying to protect it."
Again, swimming is back on at Chicago beaches except for Marion Mahoney Griffin Beach on the North Side. By 11:30 a.m. on Monday, much of the water worries washed away.
The lock and gates at the river remained closed as of Monday.