1. Upon a petition to the State Engineer, signed by one or more water users of any stream or stream system, requesting the determination of the relative rights of the various claimants to the waters thereof, the State Engineer shall, if upon investigation the State Engineer finds the facts and conditions justify it, enter an order granting the petition and shall make proper arrangements to proceed with such determination.
2. The State Engineer shall, in the absence of such a petition requesting a determination of relative rights, enter an order for the determination of the relative rights to the use of water of any stream selected by the State Engineer. As soon as practicable after the order is made and entered, the State Engineer shall proceed with such determination as provided in this chapter.
3. A water user upon or from any stream or body of water shall be held and deemed to be a water user upon the stream system of which such stream or body of water is a part or tributary.