When at least three cities and/or counties within the region have elected to become associated as members of the district in the manner provided in this chapter, and the attorney general has reviewed the official proceedings of the governing bodies of such counties and/or cities and has certified to the Governor that such counties and/or cities have elected to become associated as members of the district in the manner required by this chapter, then the Governor within fifteen days after such certification shall issue a proclamation declaring that such district has been lawfully organized with the powers as set forth in Section 17-11-15, and that it is vested with all the additional powers, rights, and duties conferred on it by this chapter. The Governor shall, in such proclamation, fix a date, time and place, within the region, for the formal organization of the governing body of such district.