United States v. Washington, 375 F. Supp. 2d 1050, 1063-64 (W.D. Wash. 2005) ; In re Gen. Adjudication of All Rights to Use Water in the Big Horn River Sys. (hereafter Big Horn I ), 753 P.2d 76, 96-97 (Wyo. 1988), aff'd sub nom. Wyoming v. United States, 492 U.S. 406, 109 S.Ct. 2994, 106 L.Ed.2d 342 (1989) (affirmed by an equally divided court without opinion), and abrogated on other grounds by Vaughn v. State, 962 P.2d 149 (Wyo. 1998) ; In re Gen. Adjudication of All Rights to Use Water in the Big Horn River Sys. (hereafter Big Horn III ), 835 P.2d 273, 278-79 (Wyo. 1992). The Ninth Circuit has recognized that New Mexico's primary-secondary analysis, despite not being "directly applicable" to Indian reservations, has several useful guidelines.

[¶ 17] Section 1–37–110 has been cited as authority for courts' post-declaratory judgment determinations in various contexts for many years. In In re General Adjudication of All Rights to Use Water in the Big Horn River System, 835 P.2d 273 (Wyo.1992), the tribes filed a motion for order to show cause why the state engineer should not be held in contempt for failing to follow an earlier declaratory judgment concerning tribal water rights. While sorting out various orders that had previously been entered in the case, we addressed the state engineer's duty to follow and implement earlier declaratory judgment rulings.

It is a scarce resource which must be effectively managed and efficiently used to meet the various demands of society. In Re General Adjudication of All Rights to Use Water in Big Horn River System, 835 P.2d 273, 279 (Wyo.1992) (plurality opinion). [¶ 36] The property has excellent water rights, some of them dating back to when Wyoming was a territory pioneering the system of priority by appropriation, which has become the model for western states.

It is a scarce resource which must be effectively managed and efficiently used to meet the various demands of society.In Re General Adjudication of All Rights to Use Water in Big Horn River System, 835 P.2d 273, 279 (Wyo.1992) (plurality opinion). [¶ 31] We presume that the legislature has acted in a thoughtful and rational manner with full knowledge of existing law when it enacts a statute.

See, e.g., Walton, 647 F.2d at 52 ("Especially in arid and semi-arid regions of the West, water is the lifeblood of the community."); In re General Adjudication of All Rights to Use Water in Big Horn River Sys., 835 P.2d 273, 279 (Wyo. 1992) ("Water is the lifeblood of Wyoming."). Whether the change of use would adversely affect the Tribes and whether such assertion of regulatory authority by the State would have a direct effect on the Tribes are legal conclusions.

We have summarized the vast factual and legal background of this litigation in prior appeals to this Court. See In re General Adjudication of All Rights to Use Water in the Big Horn River System, 803 P.2d 61 (Wyo. 1990) (Big Horn II); In re General Adjudication of All Rights to Use Water in the Big Horn River System, 835 P.2d 273 (Wyo. 1992); In re General Adjudication of All Rights to Use Water in the Big Horn River System, 753 P.2d 76, 83-86 (Wyo. 1988), cert. granted in part, 488 U.S. 1040, aff'd sub nom., Wyoming v. United States, 492 U.S. 406 (1989) ( Big Horn I). The case as a whole was divided into three phases: Phase I, Indian reserved water rights; Phase II, non-Indian federal reserved water rights; and Phase III, state water rights evidenced by a permit or certificate. Big Horn I, 753 P.2d at 85.

Id. Through prior appeals to this court, we have provided summaries of the factual and legal background of this litigation. See State v. Owl Creek Irrigation District Members, 753 P.2d 76, 83-86 (Wyo. 1988), cert. granted in part, 488 U.S. 1040, aff'd sub nom. Wyoming v. United States, 492 U.S. 406 (1989) ( Big Horn I); Alexander v. United States, 803 P.2d 61 (Wyo. 1990) ( Big Horn II); In re General Adjudication of All Rights to Use Water in the Big Horn River System, 835 P.2d 273 (Wyo. 1992); Big Horn V, 899 P.2d 848. [¶ 3] In the initial appeal, Big Horn I, 753 P.2d 76, this court was called upon to determine whether non-Indian water users could claim a federal reserved right with an 1868 priority date as successors in interest to Indian allottees who received fee lands under the General Allotment Act of 1887 (now 25 U.S.C. § 331-358) and reserved water rights through the 1868 Treaty of Fort Bridger, which established the Wind River Indian Reservation. Winters v. United States, 207 U.S. 564 (1908).

¶ 27 It is true that some courts have utilized the primary-secondary purpose test or looked to it for guidance when dealing with Indian lands. See Adair, 723 F.2d at 1408 (stating that New Mexico is not directly applicable, but establishes "several useful guidelines"); Walton, 647 F.2d at 47 (applying the test); In re the General Adjudication of all Rights to Use Water in the Big Horn River System, 835 P.2d 273, 278-79 (Wyo. 1992) [Big Horn II] (following the test). Nevertheless, we believe the significant differences between Indian and non-Indian reservations preclude application of the test to the former.

Because of the great value of water, an appropriator, according to the basic statute on abandonment, cannot hold his water rights indefinitely without using them. Wyo. Stat. § 41-3-401. In re General Adjudication of All Rights to use Water in Big Horn River System, 835 P.2d 273, 279 (Wyo. 1992). We hold that supplemental water rights are subject to abandonment under Wyo. Stat. § 41-3-401, et seq.