The head of the Illinois river watershed is separated from Lake Michigan by a low divide. In 1848 the Illinois and Michigan canal was constructed from the Chicago river across the divide to the Illinois river at a point just below La Salle, thus permitting through navigation. In 190o the sanitary district of Chicago com pleted a drainage canal from the south branch of the Chicago river to the Des Plaines river at Joliet. This, combined with work in the Chicago river, reversed the flow of the latter and permitted the flow of water from Lake Michigan through the canal into the Des Plaines and thence to the Illinois. It also provided a navigable channel 21 ft. deep, with a minimum bottom width of 200 ft., from the lake to a point between Lockport and Joliet, where a power plant was constructed. In 1908 the Illinois water way was provided for by amendment to the State's Constitution, to be financed by the sale of bonds, to permit navigation from Lockport to Utica, with the intention of connecting the Great Lakes with the Mississippi system. The waterway is designed for 9 ft. depth, and was under construction in 1928. The Federal Gov ernment has undertaken the improvement of the Illinois river with a view to securing a navigable channel of the same depth to the mouth, where connection is made with the Mississippi river.
Under authority of Sec. 10 of an act of Congress approved on March 3, 1899, the secretary of war, upon the recommendation of the chief of engineers, issued on March 3, 1925, to the sanitary district of Chicago, a permit to divert from Lake Michigan, through its main drainage canal and auxiliary channels, an amount of water not to exceed an annual average of 8,5oo cu.ft. per
second, the instantaneous maximum not to exceed 11,000 cu.ft. per second under certain conditions including the requirements that the sewage be artificially treated, that controlling works be constructed to prevent the discharge of the Chicago river into the lake, and that the water service of the city of Chicago be metered. This permit, if not previously revoked or specifically extended, becomes null and void on Dec. 31, 1929. Action has been brought by some of the Lake States to restrain the Chicago drainage dis trict from diverting water from Lake Michigan, and the matter was finally settled by the Supreme Court in favour of the Lake States in January, 1929.
Jean Nicolet is credited with being the first white man to navi gate Lake Michigan. Sent west by Champlain on a voyage of ex ploration, he threaded his way in a birch canoe from Georgian bay through the Straits of Mackinac and thus discovered Lake Michigan in the summer of 1634. Later explorers were Joliet, Marquette and La Salle.
BIBLIOGRAPHY.—History of the Great Lakes (1899) ; Transportation on the Great Lakes (War Department, 1926) ; Bulletins and Charts issued by the U. S. Lake Survey Office (1928) ; Document No. 4, Com mittee on Rivers and Harbors, 69th Congress, 1st Session ; Annual Report of the chief of engineers, War Department. (E. JA.)