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The Chicago Sanitary and Ship Canal, historically known as the Chicago Drainage Canal, is a long canal system that connects the Chicago River to the Des Plaines River. It reverses the direction of the Main Stem and the South Branch of the Chicago River, which now flows out of Lake Michigan rather than into it. The related Calumet-Saganashkee Channel does the same for the Calumet River a short distance to the south, joining the the Chicago canal about half way along its route to the Des Plaines. The two provide the only navigation for ships between the Great Lakes Waterway and the Mississippi River system. The canal was primarily built as a sewage treatment scheme. Prior to its opening in 1900, sewage from the city of Chicago was dumped into the Chicago River and flowed into Lake Michigan. The city's drinking water supply was located offshore, and there were fears that the sewage could reach the intake and cause serious disease outbreaks. Since the sewer systems were already flowing into the river, the decision was made to dam the river and reverse its flow, thereby sending all the sewage inland where it could be treated before emptying it into the Des Plaines. A secondary goal was to replace the earlier Illinois and Michigan Canal (I&M), which had originally connected Lake Michigan with the Mississippi starting in 1848, but had been unsuccessful in its attempt to widen its course. As part of the construction of the new canal, the entire route was built to allow much larger ships to navigate, it is wide and deep, over three times the size of the I&M. The I&M became a secondary route with the new canal's opening, and was shut down entirely with the creation of the Illinois Waterway network in 1933. The canal is operated by the Metropolitan Water Reclamation District of Greater Chicago. In 1999, the system was named a ''Civil Engineering Monument of the Millennium'' by the American Society of Civil Engineers (ASCE).〔(【引用サイトリンク】title=Chicago Wastewater System )〕 The Canal was listed on the National Register of Historic Places on December 20, 2011. ==Reasons for construction== Early Chicago sewage systems discharged directly into Lake Michigan or into the Chicago River, which itself flowed into the lake. The city's water supply also came from the lake, through water intake cribs located two miles offshore. There were fears that sewage could infiltrate the water supply, leading to typhoid fever, cholera and dysentery. During a tremendous storm in 1885, the rainfall washed refuse from the river far out into the lake (although reports of an 1885 cholera epidemic are untrue), spurring a panic that a future similar storm would cause a huge epidemic in Chicago. The only reason for the storm not causing such a catastrophic event was that the weather was cooler than normal. The Sanitary District of Chicago (now The Metropolitan Water Reclamation District) was created by the Illinois legislature in 1889 in response to this close call.〔(The Straight Dope: Did 90,000 people die of typhoid fever and cholera in Chicago in 1885? )〕 In addition, the canal was built to supplement and ultimately replace the older and smaller Illinois and Michigan Canal (built 1848) as a conduit to the Mississippi River system. In 1871, the old canal had been deepened in an attempt to reverse the river and improve shipping but the reversal of the river only lasted one season.〔Miller, Donald L. ''City of the Century'' (Simon & Schuster, New York, 1996) p. 427〕 The I&M canal was also badly polluted as a result of unrestricted dumping from city sewers and industries, such as the stockyards.〔(American Experience | Chicago: City of the Century | People & Events ). Pbs.org. Retrieved on 2013-07-21.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chicago Sanitary and Ship Canal」の詳細全文を読む スポンサード リンク
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