(Above) The Shoreline water taxi Shake A Leg on the main branch of the Chicago River near Wolf Point last October.

January 12, 2013 – Lake Michigan’s lower than normal level, which appears to happen every 40 years and was caused by a dry summer last year, could force the city to interrupt traffic on the Chicago River.

Responding to what it says are inaccurate media reports, the Metropolitan Water Reclamation District of Greater Chicago sent out a news release on Thursday explaining how the low lake level could not reverse the course of the river but could, if the level continues to decline, result in suspending river traffic.

If the MWRD could not take in water from Lake Michigan, Allison Fore, the district’s public affairs officer, says the oxygen level in the main branch of the Chicago River would decrease, requiring the channel to be refreshed. Working with the U.S. Army Corp of Engineers, the MWRD would coordinate a schedule to allow new water into the main channel.

“This schedule may cause a suspension of river traffic for a certain time frame,” says Fore (left). “It would not be prolonged or stop traffic altogether.”

Operation of the locks – that permit traffic between the Chicago River and Lake Michigan – would not be restricted, according to Fore.

In 1900, the flow of the Chicago River was reversed to keep sewage away from Lake Michigan, the city’s source of clean water. Despite the low lake level, Fore says gates on the river “will not allow a reversal of the river under any circumstance with the exception of major storm events,” which happen, she says, about once a year.

While Fore is not calling it a crisis, more dry summers could result in “significant water management developments” in Chicago. “It certainly highlights the value of water and the need to respect our use. Every citizen should certainly do their best to conserve water and use it wisely, not wastefully.”

Lake Michigan’s level peaked most recently in 1984 and has now returned to a level last seen in 1964.