Sign up for the Morning Brief email newsletterto get weekday updates from The Weather Channel and our meteorologists. The Chicago River was re-engineered in the late 1800s to flow backward. But city officials can turn it around to redirect excess water during heavy rainfall events. That happened Sunday, for the first time in more than three years. Why does the Chicago River flow backward? -In the late 1800s, Chicago’s population was booming and from slaughterhouses, stock yards and humans all...