Opinion of the Court
ents 35.
That argument first raises the question whether it is even possible to hold “title,” as ANILCA uses the term, to reserved water rights. 16 U. S. C. §3102(2). Those rights, as all parties agree, are “usufructuary” in nature, meaning that they are rights for the Government to use—whether by withdrawing or maintaining—certain waters it does not own. See Niagara Mohawk Power Corp., 347 U. S., at 246; Brief for Petitioner 36; Brief for Respondents 36. The Park Service has found a couple of old cases suggesting that a person can hold “title” to such usufructuary interests. See ibid.; Crum v. Mt. Shasta Power Corp., 220 Cal. 295, 307, 30 P. 2d 30, 36 (1934); Radcliff’s Ex’rs v. Mayor of Brooklyn, 4 N. Y. 195, 196 (1850). But the more common understanding, recently noted in another ANILCA case, is that “reserved water rights are not the type of property interests to which title can be held;” rather, “the term ‘title’ applies” to “fee ownership of property” and (sometimes) to “possessory interests” in property like those granted by a lease. See Totemoff v. State, 905 P. 2d 954, 965 (Alaska 1995) (collecting cases); Brief for State of Idaho et al. as Amici Curiae 21–22 (same). And we see no evidence that the Congress enacting ANILCA meant to use the term in any less customary and more capacious sense.
But even assuming so, the Nation River itself would not thereby become “public land” in the way the Park Service argues. Under ANILCA’s definition, the “public land” at issue would consist only of the Federal Government’s specific “interest” in the River—that is, its reserved water right. §3102(1), (3). And that reserved right, by its nature, is limited. It does not give the Government plenary authority over the waterway to which it attaches. Rather, the interest merely enables the Government to take or maintain the specific “amount of water”—and “no more”—required to “fulfill the purpose of [its land] reservation.”
