65 ILCS 5/11-87-1
Whenever in the judgment of the corporate authorities of any city or village it becomes necessary to change or re-locate the channel, course, or bed of any natural or artificial water course or stream within the corporate limits of the city or village, in order to properly lay out, establish, open, alter, widen, extend, grade, pave, or otherwise improve the streets, alleys, avenues, and sidewalks, or any of them in any part of the city or village, the corporate authorities are hereby vested with the power to provide by ordinance for the laying out, establishing, opening, altering, widening, extending, grading, paving, or otherwise improving those streets, alleys, avenues, and sidewalks, or any of them in any such part of the city or village, and by the same ordinance to provide for the changing or re-locating of the channel, course, or bed of any such water course or stream within the corporate limits of the city or village. The entire improvement provided for by such an ordinance shall constitute a local improvement, the cost of which may be paid for by special assessment, by special taxation of contiguous property, or by general taxation, or otherwise, as the corporate authorities by ordinance shall direct, and in providing for such an improvement they may proceed in accordance with the provisions of Article 9.
In case the corporate authorities re-locate any such channel or water course, the title of the State of Illinois in and to any land artificially made or reclaimed within the corporate limits of any city or village, which prior to the re-location was, but after the re-location is no longer a part of the channel, course, or bed of the natural or artificial water course or stream, shall vest in fee simple absolute, without further act or deed, in the city or village which so re-locates that channel, course, or bed. The State of Illinois shall take the same title and to the same extent in territory in metes and bounds in and to the channel course or bed of the watercourse or stream, after its re-location by the city or village, as it had in the channel course or bed of the watercourse or stream, before its re-location.
65 ILCS 5/11-87-1