CERTIORARI TO THE SUPREME COURT OF COLORADO.
Mr. Justice Douglas delivered the opinion for a unanimous Court. Mr. Justice Harlan, though joining in the opinion, filed a concurring statement, post, p. 530.
MR. JUSTICE DOUGLAS delivered the opinion of the Court.
Eagle River is a tributary of the Colorado River; and Water District 37 is a Colorado entity encompassing all Colorado lands irrigated by water of the Eagle and its tributaries. The present case started in the Colorado courts and is called a supplemental water adjudication under Colo. Rev. Stat. Ann. § 148-9-7 (1963). The Colorado court issued a notice which, inter alia, asked all
owners and claimants of water rights in those streams "to file a statement of claim and to appear . . . in regard to all water rights owned or claimed by them." The United States was served with this notice pursuant to 43 U. S. C. § 666.*fn1 The United States moved to be dismissed as a party, asserting that 43 U. S. C. § 666 does not constitute consent to have adjudicated in a state court the reserved water rights of the United States.
The objections of the United States were overruled by the state District Court and on a motion for a writ of prohibition the Colorado Supreme Court took the same view. 169 Colo. 555, 458 P. 2d 760. The case is here on a petition for certiorari, which we granted. 397 U.S. 1005.
We affirm the Colorado decree.
It is clear from our cases that the United States often has reserved water rights based on withdrawals from the public domain. As we said in Arizona v. California, 373 U.S. 546, the Federal Government had the authority both before and after a State is admitted into the Union "to reserve waters for the use and benefit of
federally reserved lands." Id., at 597. The federally reserved lands include any federal enclave. In Arizona v. California we were primarily concerned with Indian reservations. Id., at 598-601. The reservation of waters may be only implied and the amount will reflect the nature of the federal enclave. Id., at 600-601. Here the United States is primarily concerned with reserved waters for the White River National Forest, withdrawn in 1905, Colorado having been admitted into the Union in 1876.
The United States points out that Colorado water rights are based on the appropriation system which requires the permanent fixing of rights to the use of water at the time of the adjudication, with no provision for the future needs, as is often required in case of reserved water rights.*fn2 Ibid. Since those rights may potentially be at war with appropriative rights, it is earnestly urged that 43 U. S. C. § 666 gave consent to join the United States only for the adjudication of water rights which the United States acquired pursuant to state law.
The consent to join the United States "in any suit (1) for the adjudication of rights to the use of water of a river system or other source" would seem to be all-inclusive. We deem almost frivolous the suggestion that the Eagle and its tributaries are not a "river system" within the meaning of the Act. No suit by any State could possibly encompass all of the water rights in the entire Colorado River which runs through or touches many States. The "river system" must be read as embracing one within the particular State's jurisdiction. With that to one side, the first clause of § 666 ...