The appropriation of water as supplemental supply is defined in detail by W.S. 41-3-113. In general, it involves the appropriation of direct flow water from another surface water source to augment or supplement the available water for an existing appropriation for which the original source of supply does not provide a full supply. The amount of water, which may be diverted is the amount available, in priority, to bring the total water diverted from all surface water sources up to the original appropriated amount.
037-1 Wyo. Code R. § 1-10