U.S. waterway linking the south branch of the Chicago River with the Des Plaines River at Lockport, Illinois. The chief purpose of the canal, conceived in 1885, was to reverse the flow of the Chicago River away from Lake Michigan in order to halt pollution of the lake waters by the city's sewage. Construction of the canal was the largest earth-moving operation undertaken on the North American continent up to that time and was notable for training a generation of engineers, several of whom later worked on the Panama Canal. Opened in 1900, the Chicago canal was acquired in 1930 by the United States government. It has a length of 30 mi (48 km), minimum width of 160 ft (50 m), depth of 9 ft (2.7 m), and 2 locks. It was eventually linked to the Little Calumet River by the Calumet Sag Channel.