Opinion ID: 1253871
Heading Depth: 2
Heading Rank: 4

Heading: protection against off-reservation pumping

Text: ¶ 33 Next is the question what level of protection federal reserved right holders may claim against groundwater pumping that depletes their water supply. Are they limited, as the state law parties contend, to such protection as state law offers to state and private appropriators, or did the trial court correctly determine that the federal reserved right entails whatever broader protection may be necessary to maintain sufficient water to accomplish the purpose of a reservation? ¶ 34 We answer this question first with respect to federal reservations that enjoy a reserved right to surface waters. As we have indicated in previous discussion, the common law of Arizona does not permit surface appropriators to protect their source of surface waters from depletion by groundwater pumping unless that pumping draws from the relatively narrow category of subflow. See supra ¶¶ 8-10. More distant pumping within a common aquifer is governed by the relatively unfettered doctrine of reasonable use. See supra n. 3. Thus, for example, if Cappaert had arisen in Arizona, the application of state law might have precluded any restriction of adjoining pumping and have permitted Devil's Hole to be pumped dry. ¶ 35 The Salt River Project points out, however, that the standard for defining subflow awaits our further review and may conceivably be set sufficiently broadly to protect the surface water rights of some or all of the federal reservations. [11] We acknowledge that possibility, but at this stage of the adjudication we must provide for the contrary possibility as well. The question before us is not whether any particular reservation is now entitled to broader protection than state law provides. [12] The question is rather whether a federal reservation may invoke broader protection than state law provides if state law turns out to be inadequate to preserve the waters necessary to accomplish the purpose of the reservation. [13] ¶ 36 In our view, Cappaert provides an explicit answer to that question. First, Cappaert tells us that determination of reserved water rights is not governed by state law but derives from the federal purpose of the reservation. 426 U.S. at 145, 96 S.Ct. 2062. Second, it tells us that the United States can protect its water from subsequent diversion, whether the diversion is of surface or groundwater. Cappaert, 426 U.S. at 143, 96 S.Ct. 2062. ¶ 37 What Cappaert holds with respect to the protection of surface waters, our discussion in Part III enables us to apply to the protection of groundwater as well. We have held that the federal reserved right extends to groundwater when groundwater is necessary to accomplish the purpose of a federal reservation. We similarly hold that once a federal reservation establishes a reserved right to groundwater, it may invoke federal law to protect its groundwater from subsequent diversion to the extent such protection is necessary to fulfill its reserved right. ¶ 38 We thus affirm the trial court's conclusion that federal reserved rights holders enjoy greater protection from groundwater pumping than do holders of state law rights. We do not, however, read the case law to require a zero-impact standard of protection for federal reserved rights. The Supreme Court has repeatedly acknowledged that the reserved rights doctrine reserves only that amount of water necessary to fulfill the purpose of the reservation, no more. Cappaert, 426 U.S. at 141, 96 S.Ct. 2062; see also United States v. New Mexico, 438 U.S. at 700 n. 4, 98 S.Ct. 3012, 57 L.Ed.2d 1052 (1978). In Cappaert, the Court affirmed an injunction appropriately tailored ... to minimal need, curtailing pumping only to the extent necessary to preserve an adequate water level at Devil's Hole. Id. at 141, 96 S.Ct. 2062. If injunctions should ultimately prove necessary in this case, they shall likewise be appropriately tailored to minimal need. ¶ 39 In Part III we declined in the abstract to declare a standard for determining the purpose of a reservation. We here decline in the abstract to define how imminent a threat to a reservation's essential waters must be in order to warrant injunctive relief. The latter standard, like the former, should be grounded in the bedrock of the facts.