70 ILCS 1810/4a
Any changes and modifications in harbor plans within the area of the Port District from time to time recommended by the District or any comprehensive plan for the development of the port facilities adopted by said District, pursuant to authority granted by this Act, shall be submitted to the Department of Natural Resources of the State of Illinois for approval, and the approval thereof by that Department shall be conclusive evidence, for all purposes, that such changes and modifications conform to the provisions of this Act; provided, however, that no such changes or modifications shall be submitted by the District or approved by the Department of Natural Resources which reduce the total area of Senator Dan Dougherty Harbor to less than 350 acres, or the basin thereof to an area less than the Federal Navigational Channel. The title to certain lands in and near Lake Calumet in the City of Chicago acquired by the Port District by the deed heretofore made by the City of Chicago to said District is hereby confirmed; excepting, however, so much of such lands as fall within the limits of the water area of Senator Dan Dougherty Harbor. If any changes or modifications should at any time or times hereafter be made in harbor plans, as herein authorized, which have the effect of altering the water area of the Senator Dan Dougherty Harbor, then and in that event the District shall have and be entitled to all the right, title and interest of the State of Illinois in and to any of the lands so reclaimed which, by reason of such future changes or modifications, thereafter cease to form a part of the water area of the Senator Dan Dougherty Harbor.
70 ILCS 1810/4a