The salmon began spawning in East Chicago after the city built a new plant and switched from using chlorine to purify the water to using banks of ultraviolet light bulbs. The open channel behind the plant that runs into the Grand Calumet was a murky brown stream with a faint chemical smell from the chlorine before the change, but turned into a natural haven afterward.
When the fish returned, so did herons, kingfishers, then foxes and a colony of beavers. Naturalists from the Shedd Aquarium in Chicago and environmental groups have identified dozens of fish species outside the plant in numbers common only to the cleanest freshwater streams: rainbow trout, crayfish and largemouth and smallmouth bass.
Tragedy of the Commons: 50 Years Later
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