Colorado River Water Conservation District v. United States

Mr. Justice Brennan delivered the opinion of the Court.

The McCarran Amendment, 66 Stat. 560, 43 U. S. C. § 666, provides that “consent is hereby given to join the United States as a defendant in any suit (1) for the adjudication of rights to the use of water of a river system or other source, or (2) for the administration of such [*803] rights, where it appears that the United States is the owner of or is in the process of acquiring water rights by appropriation under State law, by purchase, by exchange, or otherwise, and the United States is a necessary party to such suit.” The questions presented by this case concern the effect of the McCarran Amendment upon the jurisdiction of the federal district courts under 28 U. S. C. § 1345 over suits for determination of water rights brought by the United States as trustee for certain Indian tribes and as owner of various non-Indian Government claims.[1]

[*804] I It is probable that no problem of the Southwest section of the Nation is more critical than that of scarcity of water. As southwestern populations have grown, conflicting claims to this scarce resource have increased. To meet these claims, several Southwestern States have established elaborate procedures for allocation of water and adjudication of conflicting claims to that resource.[2] In 1969, Colorado enacted its Water Rights Determination and Administration Act[3] in an effort to revamp its legal procedures for determining claims to water within the State.