The powers conferred by this article are in addition and supplemental to the powers conferred by any other law. It is the purpose and intent of this article to create full and complete additional and alternate methods for the exercise of such powers. Insofar as the provisions of this article are inconsistent with the provisions of any existing law, the provisions of this article control. This article is necessary for and to secure the public health, safety, convenience and welfare of the owners and occupants of lands lying within the boundaries of the district and shall be liberally construed to effect its purposes.