Opinion of the Court
Corp., 347 U. S. 239, 247, n. 10 (1954); Brief for Respondents 33. In contrast, the lands beneath those waters—typically called submerged lands—can be owned, and the water regulated on that basis. But that does not help the Park Service because, as noted earlier, the Submerged Lands Act gives each State “title to and ownership of the lands beneath [its] navigable waters.” 43 U. S. C. §1311; see supra, at 4. That means Alaska, not the United States, has title to the lands beneath the Nation River.
So the Park Service argues instead that the United States has “title” to an “interest” in the Nation River, under what is called the reserved-water-rights doctrine. See Brief for Respondents 32–37. The canonical statement of that doctrine goes as follows: “[W]hen the Federal Government withdraws its land from the public domain and reserves it for a federal purpose, the Government, by implication, reserves appurtenant water then unappropriated to the extent needed to accomplish the purpose of the reservation.” Cappaert v. United States, 426 U. S. 128, 138 (1976). For example, this Court decided that in reserving land for an Indian tribe, the Government impliedly reserved sufficient water from a nearby river to enable the tribe to farm the area. See Winters v. United States, 207 U. S. 564, 576 (1908). And similarly, we held that in creating a national monument to preserve a species of fish inhabiting an underground pool, the United States acquired an enforceable interest in preventing others from depleting the pool below the level needed for the fish to survive. See Cappaert, 426 U. S., at 147. According to the Park Service, the United States has an analogous interest in the Nation River and other navigable waters in Alaska’s national parks. “Because th[e] purposes [of those parks] require that the waters within [them] be safeguarded against depletion and diversion,” the Service contends, “Congress’s reservations of park lands also reserved interests in appurtenant navigable waters.” Brief for Respond-
