Chicagoist provides a concise summary of how plans to stop the Asian Carp are tied to the future of the Chicago River.
Also, an excellent two-part article in the Milwaukee Journal Sentinel which tells the history of the Chicago River, its current degraded state and how the river is still connected to the growth of the region.
Chicago and Milwaukee have thrown insults at each other in the past over each city's stewardship of Lake Michigan. Politicians in Chicago blame Milwaukee for beach closures whenever a storm overflows Milwaukee's sewer system into the lake. In civilized Illinois, the implication is, we don't dump sewage back into the same lake where we get our drinking water. But as the Journal Sentinel article shows, Chicago's ability to drain its waste away from the city, out of sight, has allowed it to dump far more untreated sewage into the environment than Milwaukee ever does, by sending it all downstream and out of mind.