This act constitutes full and complete authority for the purposes set out therein, and no procedure or proceedings other than those required by this act shall be necessary for the performance of the provisions hereof. The powers conferred by this act shall be in addition and supplemental to and not in substitution for, and the limitations imposed by this act shall not affect, the powers conferred by any other law. The provisions of this act are severable, and if any provision, section, subsection, sentence, clause or phrase of this act, including, but not limited to the provisions relating to any of the sources of revenues for payment of bonds authorized pursuant to this act, be for any reason held to be unconstitutional or otherwise invalid by any court of competent jurisdiction, such decision shall not affect the validity of the remaining portions of this act; and the legislature hereby declares that it would have passed this act and each provision, section, subsection, sentence, clause or phrase thereof irrespective of the fact that any one or more of the same shall be declared invalid.