Whenever any ten (10) owners of real property in any city shall petition the city council to lay off and establish an improvement district embracing all of the real property in the city, the city council may, by ordinance, lay off the entire city into one (1) improvement district to be known as “Consolidated Water and Light Improvement District of the City of ”, if it finds that the acquiring and taking over of an existing waterworks plant and system theretofore acquired or constructed by an improvement district named in the petition, and the taking over and acquiring of an existing electric light plant and system theretofore acquired or constructed by an improvement district named in the petition, and the consolidation of the plants and systems, and the enlarging, extending, and repairing the existing plants and systems constitute a single improvement of a local nature beneficial to all of the real property in the city.