Any city desiring to acquire and operate or acquire or operate a city irrigation system under the provisions of sections 50-1801 through 50-1835 for any part or all of such city shall pass and publish an ordinance describing the exterior boundaries of such irrigation system. Thereafter the boundary of such irrigation system may, from time to time, be contracted, extended or enlarged by ordinance of such city; a copy of such ordinance duly certified to be correct by the city clerk shall be recorded in the office of the recorder of the county wherein such city is situated.