Sections 10-615 and 10-616 shall be deemed to provide an additional, alternative, and complete method for doing the things authorized in such sections, shall be deemed and construed to be supplemental and additional to the powers conferred by any other laws, and shall not be regarded to be in degradation of any powers existing on April 7, 1987, except that insofar as sections 10-615 and 10-616 are inconsistent with any other law or home rule charter, such sections shall be controlling.