Columbus Dr Bridge

You can't talk about the Chicago River without talking about pollution. Historically, one of the river's primary roles was to flush waste out of the city. Part of the South Branch, where stock yards and meat packing plants were common in the 1900s, was given the nickname Bubbly Creek because gases from decomposing waste gurgled up from the riverbed. Even the famous practice of dyeing the river green for St. Patrick's Day has a pollution connection. Today, vegetable dye is used to color the river in celebration, but the custom began in 1961 when plumbers used dye to trace the sources of illegal pollution.

Storm drains like this one near the Columbus Drive Bridge are a part of the city's efforts to prevent polluted stormwater and sewage from flowing into the river and Lake Michigan.