The council may, from time to time, call public hearings to ascertain whether the public necessity, health or safety requires the removal of poles and overhead wires and associated overhead structures from any particular area or areas within the city and the underground installation of wires and facilities for supplying electric, communication or similar or associated service. The city clerk shall notify all affected property owners and utilities by mail of the time and place of such hearings at least thirty days prior to the date thereof. If, after any such public hearing, the council finds that the public necessity, health or safety requires such removal and such underground installation within any such area, the council shall by ordinance declare such an area an underground utility district. Such ordinance shall include a description of the area comprising such district and shall fix the time within which such poles and overhead wires and other associated overhead structures must be removed and within which affected property owners must be ready to receive underground service. The council shall allow a reasonable time for such removal, having due regard for the availability of necessary labor, materials and equipment for such removal and for the installation of such underground facilities as may be occasioned thereby. (Prior code § 8400.2)