Chicago's picturesque lakeshore and elevated downtown streets today obscure the city's foundation on a low-lying lake plain. In the 1800s, however, rapid growth and poor natural drainage almost choked residents in their own wastes. Waterborne diseases - typhoid fever, cholera, and dysentery - reached epidemic levels, killing as many as 90,000 people in 1885 when a storm flushed sewage from the Chicago River into Lake Michigan - the city's source of drinking water. The city had installed some sewers in the 1850s to improve local drainage, but, because waste treatment technology was inadequate to handle the volume of waste generated by a large city, the sewers simply discharged into the river. An attempt in 1865 to pump Chicago River water into the Illinois and Michigan Canal, which linked the Chicago River with the Des Plaines and Illinois Rivers to the west, was insufficient during wet years to move pollution away from the city and from the Lake Michigan water intakes. So, in 1885, a citizens' association proposed construction of a larger canal that could effectively reverse the direction of the Chicago River, dilute pollution, and send it down the Mississippi River.
According to an article by Richard Lanyon, director of research and development for the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC), published in The Wetlands Initiative's newsletter (www.wetlands-initiative.org), the Commission on Drainage and Water Supply, formed in 1886, studied the issue and offered three alternatives: discharge sewage into Lake Michigan south of the city and bring in fresh water from north of the city; dispose of sewage on land; or discharge sewage into the Des Plaines River. The third option was deemed most cost effective - $28 million.
More than 460,000 cubic yards of masonry line the walls of the Chicago Sanitary and Ship Canal.
The Illinois State Legislature established the Sanitary District of Chicago (SDC) in 1889 to develop a sanitation system for the Chicago region, protect the region's water supply, expand navigable waterways, and develop a system to handle stormwater. But with a contentious Board of Trustees, the SDC got off to a rough start, according to Lanyon. The SDC had four chief engineers in three years - Lyman E. Cooley, William Worthen, Samuel Artingstall, and Benezette Williams. Finally, Isham Randolph, appointed chief engineer in 1893, remained long enough to oversee construction of the Chicago Drainage Canal, later renamed the Sanitary and Ship Canal.
Work began Sept. 3, 1892, excavating the 28-mile canal. The route required blasting more than 12 million cubic yards of rock and excavating more than 29 million cubic yards of soil. The canal was built to a depth of 25 feet and ranged in width from 160 feet to 306 feet. It was designed to accommodate a gravity water flow of 10,000 cubic feet per second, enough to reverse the direction of the Chicago River from east to west, drawing in sufficient Lake Michigan water to dilute Chicago's sewage.
The Chicago Sanitary and Ship Canal opened in January 1900, despite objections from Missouri officials about the sewage discharges and from other Great Lakes states about lake water diversion. The canal's capacity was increased in subsequent years with construction of the North Shore Channel and the Calumet-Sag Channel, which reversed the flow of the Calumet River. These expansions also increased the canal's navigation capabilities.
A U.S. Supreme Court order in 1930 required the SDC to decrease diversion of lake water, leading to construction of a lock at the mouth of the Chicago River. By that time, however, Chicago's improved sewage- and water- treatment systems had decreased the canal's importance for sanitation. As early as 1917, the typhoid death rate in Chicago had declined to the lowest of any major U.S. city.
Some of the Chicago Sanitary and Ship Canal's environmental impacts, however, are still being addressed. The U.S. Army Corps of Engineers announced in March 2004 its intention to complete a $4.4-million, electrical-field barrier across the canal to stop migration into the Great lakes of an invasive and destructive fish species, the Asian Carp. Reversing a river's flow