70 ILCS 1230/4
The title to any such extension or connection of such park or parks, boulevards, driveways and parkways, and to the bed thereof shall be, and hereby becomes vested in such board of park commissioners for public purposes, and the same shall thereby become a part of the public park or parks under the control of such board, and shall thenceforth be maintained and controlled by such board in the manner provided by law, for the government and maintenance of other parks, boulevards and driveways under its control, and in all cases where any boulevard, driveway or parkway is extended, or constructed, under the provisions of this act, the title to the submerged lands lying between the shore of such public waters, and the inner line of the extension of such boulevard, driveway or parkway, shall be, and thereby becomes vested in such board of park commissioners for public purposes; and in case any such park, boulevard, driveway or parkway, extension or connection as provided in this act, shall be made into, over or upon the bed of Lake Michigan by any such board of park commissioners, then the right, title and interest of the State of Illinois in and to the bed of so much of said Lake Michigan shall be vested in such board of park commissioners as in other cases provided in this act, and for the same purposes and with the same rights and power.
70 ILCS 1230/4