615 ILCS 65/1

A harbor, having a basin and slips, a depth of not less than minus twenty-one and thirty-four one-hundredths (21.34) feet Chicago datum and a total area of not less than five hundred (500) acres of which not less than three hundred (300) acres shall be in the basin, may be constructed by the City of Chicago in and near Lake Calumet in the City of Chicago.