(1) The powers conferred by this part shall be in addition and supplemental to the powers conferred by any other law, and are not in substitution for such powers, and the limitations imposed by this part shall not affect such powers.
(2) The powers herein granted may be exercised without regard to requirements, restrictions or procedural provisions contained in any other law or charter, except as herein expressly provided.
(3) Any metropolitan government or any home rule municipality authorized hereunder to create a water and wastewater treatment authority may do so without the necessity of a charter amendment, notwithstanding anything in its charter to the contrary.