(a) There is created a unit of local government by the name of Rock Island Regional Port District that includes all the territory within the corporate limits of the City of Rock Island as those corporate limits exist on the effective date of this Act. Territory may be annexed into the Port District in the manner provided in Section 15. The Port District or participating municipality may sue and be sued in the Port District's or municipality's respective corporate name, but execution shall not issue against any of the property or assets of the Port District or participating municipality. The Port District may adopt a common seal and change the same at its pleasure. All property of every kind belonging to the Port District is exempt from taxation, except that taxes may be assessed and levied upon a lessee of the Port District by reason of the value of a leasehold estate separate and apart from the fee and upon improvements as are constructed and owned by others than the Port District. All property of the Port District is public ground owned by a municipal corporation and used exclusively for public purposes within the tax exemption provisions of Sections 15-10, 15-15, 15-20, 15-30, 15-75, 15-140, 15-155, and 15-160 of the Property Tax Code.