615 ILCS 5/18c
The Department of Natural Resources, may also, upon the issuance of a permit under the provisions of Section 18 of this Act, enter into an agreement with any person, firm, or corporation, by the terms of which agreement such person, firm, or corporation, may build or place in, upon or below the bed of that portion of Chicago Harbor in Lake Michigan lying South of the Chicago River Entrance, West of the U. S. Inner Breakwater, North of East 11th Place extended and East of the Harbor Line established by the Secretary of War in Lake Michigan, May 3, 1940, or lying North of Navy Pier, South of the Chicago Central Water Filtration Plant, East of a line running north through the inner west end of Navy Pier, and West of a line running North through the outer or east end of Navy Pier, any causeway, harbor or mooring facilities for watercraft, and agrees to pay a rental, charges or fee to the State of Illinois for the use and occupation of any State owned lands which may be authorized to be utilized for such purposes; the rental, charge or fee shall be determined by said Department. No such agreement permitting any causeway, harbor or mooring facilities for watercraft in, upon or below the bed of said portion of Chicago Harbor in Lake Michigan shall be made, which by its terms, permits the use and occupation of State owned lands for a period of over 20 years, nor shall such agreement be entered into unless provision therein is made that such agreement shall be revocable at the will of said Department to permit use thereof by the State of Illinois for any public purpose.
615 ILCS 5/18c