How Chicago Reversed Its River in 1900 and Why It Still Flows Backwards

In 1900, Chicago engineered a reversal of the Chicago River's natural flow to protect its drinking water supply from sewage contamination. The ambitious project was designed to divert waste away from Lake Michigan, the city's primary water source, and significantly improved public health outcomes over the following decades. However, the altered waterway sparked legal battles from neighboring states, including Missouri, who opposed the environmental impact. More than a century later, the reversed river continues to pose unintended ecological challenges that threaten local ecosystems.