JUSTICE MARSHALL delivered the opinion of the Court.
This case concerns the proper apportionment between New Mexico and Colorado of the water of an interstate river. The water of the Vermejo River is at present fully appropriated by users in New Mexico. Colorado seeks to divert water for future uses. Invoking this Court's original jurisdiction under Art. III, § 2, of the Constitution, Colorado brought this action for an equitable apportionment of the water of the Vermejo River. A Special Master appointed by the Court recommended that Colorado be permitted a diversion of 4,000 acre-feet per year. The case is before us on New Mexico's exceptions to the Special Master's report.
The Vermejo River is a small, nonnavigable river that originates in the snow belt of the Rocky Mountains in southern Colorado and flows southeasterly into New Mexico for a distance of roughly 55 miles before it joins the Canadian River. The major portion of the river is located in New Mexico. The Colorado portion consists of three main tributaries that combine to form the Vermejo River proper approximately one mile below the Colorado-New Mexico border. At present there are no uses of the water of the Vermejo River in Colorado, and no use or diversion has ever been made in Colorado. In New Mexico, by contrast, farmers and industrial users have diverted water from the Vermejo for many years. In 1941 a New Mexico state court issued a decree apportioning the water of the Vermejo River among the various New Mexico users.
In 1975, a Colorado corporation, Colorado Fuel and Iron Steel Corp. (C. F. & I.), obtained in Colorado state court a conditional right to divert 75 cubic feet per second from the headwaters of the Vermejo River.
In June 1978 Colorado moved for leave to file an original complaint in this Court. New Mexico opposed the motion. On April 16, 1979, we granted Colorado's motion and appointed
The Special Master found that most of the water of the Vermejo River is consumed by the New Mexico users and that very little, if any, reaches the confluence with the Canadian River. He thus recognized that strict application of the rule of priority would not permit Colorado any diversion since the entire available supply is needed to satisfy the demands of appropriators in New Mexico with senior rights. Nevertheless, applying the principle of equitable apportionment established in our prior cases, he recommended permitting Colorado a transmountain diversion of 4,000 acre-feet
Explaining his conclusion, the Special Master noted that any injury to New Mexico would be restricted to the Conservancy District, the user in New Mexico furthest downstream, since there was sufficient water in the Vermejo River for the three other principal New Mexico water users, Vermejo
The Special Master's recommendation appears to rest on two alternative grounds: first, that New Mexico could compensate for some or all the Colorado diversion through reasonable water conservation measures;
We conclude that the criteria relied upon by the Special Master comport with the doctrine of equitable apportionment as it has evolved in our prior cases. We thus reject New
Equitable apportionment is the doctrine of federal common law that governs disputes between States concerning their rights to use the water of an interstate stream. Kansas v. Colorado, 206 U.S. 46, 98 (1907); Connecticut v. Massachusetts, 282 U.S. 660, 670-671 (1931). It is a flexible doctrine which calls for "the exercise of an informed judgment on a consideration of many factors" to secure a "just and equitable" allocation. Nebraska v. Wyoming, 325 U.S. 589, 618 (1945). We have stressed that in arriving at "the delicate adjustment of interests which must be made," ibid., we must consider all relevant factors, including:
Our aim is always to secure a just and equitable apportionment "without quibbling over formulas." New Jersey v. New York, 283 U.S. 336, 343 (1931).
The laws of the contending States concerning intrastate water disputes are an important consideration governing equitable apportionment. When, as in this case, both States recognize the doctrine of prior appropriation, priority becomes
In reaching his recommendation the Special Master did not focus exclusively on the rule of priority, but considered other factors such as the efficiency of current uses in New Mexico and the balance of benefits to Colorado and harm to New Mexico. New Mexico contends that it is improper to consider these other factors. It maintains that this Court has strictly applied the rule of priority when apportioning water between States adhering to the prior appropriation doctrine, and has departed from that rule only to protect an existing economy built upon junior appropriations. Since there is no existing economy in Colorado dependent upon the use of water from the Vermejo River, New Mexico contends that the rule of priority is controlling. We disagree with this inflexible interpretation of the doctrine of equitable apportionment.
Our prior cases clearly establish that equitable apportionment will protect only those rights to water that are "reasonably required and applied." Wyoming v. Colorado, 259 U.S. 419, 484 (1922). Especially in those Western States where water is scarce, "[t]here must be no waste . . . of the `treasure' of a river. . . . Only diligence and good faith will keep the privilege alive." Washington v. Oregon, 297 U.S. 517, 527 (1936). Thus, wasteful or inefficient uses will not be protected. See ibid.; Nebraska v. Wyoming, supra, at 618. Similarly, concededly senior water rights will be deemed forfeited or substantially diminished where the rights have not been exercised or asserted with reasonable diligence. Washington v. Oregon, supra, at 527-528; Colorado v. Kansas, 320 U.S. 383, 394 (1943).
We conclude that it is entirely appropriate to consider the extent to which reasonable conservation measures by New Mexico might offset the proposed Colorado diversion and thereby minimize any injury to New Mexico users. Similarly, it is appropriate to consider whether Colorado has undertaken reasonable steps to minimize the amount of diversion that will be required.
In addition, we have held that in an equitable apportionment of interstate waters it is proper to weigh the harms and benefits to competing States. In Kansas v. Colorado, where we first announced the doctrine of equitable apportionment, we found that users in Kansas were injured by Colorado's upstream diversions from the Arkansas River. 206 U. S., at 113-114, 117. Yet we declined to grant any relief to Kansas on the ground that the great benefit to Colorado outweighed the detriment to Kansas. Id., at 100-101, 113-114, 117. Similarly, in Nebraska v. Wyoming, we held that water rights in Wyoming and Nebraska, which under state law were senior, had to yield to the "countervailing equities" of an established economy in Colorado even though it was based on junior appropriations. 325 U. S., at 622. We noted that the rule of priority should not be strictly applied where it "would work more hardship" on the junior user "than it would bestow benefits" on the senior user. Id., at 619. See also Washington v. Oregon, supra, at 522. The same principle is applicable in balancing the benefits of a diversion for proposed uses against the possible harms to existing
We recognize that the equities supporting the protection of existing economies will usually be compelling. The harm that may result from disrupting established uses is typically certain and immediate, whereas the potential benefits from a proposed diversion may be speculative and remote. Under some circumstances, however, the countervailing equities supporting a diversion for future use in one State may justify the detriment to existing users in another State. This may be the case, for example, where the State seeking a diversion demonstrates by clear and convincing evidence that the benefits of the diversion substantially outweigh the harm that might result.
We conclude, therefore, that in the determination of an equitable apportionment of the water of the Vermejo River the rule of priority is not the sole criterion. While the equities supporting the protection of established, senior uses are substantial, it is also appropriate to consider additional factors relevant to a just apportionment, such as the conservation measures available to both States and the balance of harm and benefit that might result from the diversion sought by Colorado.
Applying the doctrine of equitable apportionment, the Special Master recommended that Colorado be permitted to divert 4,000 acre-feet of water per year from the headwaters of the Vermejo River. Because all of the water of the Vermejo River is currently consumed by New Mexico appropriators, the recommended diversion would necessarily reduce the amount of water available to New Mexico.
In explaining the basis for his recommendation, the Special Master stated that the diversion would not "materially affect" existing New Mexico appropriations. This conclusion appears to reflect certain assumptions about the ability of New Mexico users to implement water conservation measures. See supra, at 181, and n. 7. The Special Master also concluded that any injury to New Mexico would be "more than offset" by the benefits to Colorado. Report of Special Master 23. Both the availability of conservation measures and a weighing of the harm and benefits that would result from the diversion are factors relevant to the determination of a just and equitable apportionment. However, the Special Master did not clearly state the factual findings supporting his reliance on these factors. Accordingly, we remand for additional factual findings. In particular, we request specific findings concerning the following areas:
(1) the existing uses of water from the Vermejo River, and the extent to which present levels of use reflect current or historical water shortages or the failure of existing users to develop their uses diligently;
(2) the available supply of water from the Vermejo River, accounting for factors such as variations in streamflow, the needs of current users for a continuous supply, the possibilities of equalizing and enhancing the water supply through water storage and conservation, and the availability of substitute sources of water to relieve the demand for water from the Vermejo River;
(4) the precise nature of the proposed interim and ultimate use in Colorado of water from the Vermejo River, and the benefits that would result from a diversion to Colorado;
(5) the injury, if any, that New Mexico would likely suffer as a result of any such diversion, taking into account the extent to which reasonable conservation measures could offset the diversion.
The flexible doctrine of equitable apportionment clearly extends to a State's claim to divert water for future uses. Whether such a diversion should be permitted will turn on an examination of all factors relevant to a just apportionment. It is proper, therefore, to consider factors such as the extent to which reasonable conservation measures by existing users can offset the reduction in supply due to diversion, and whether the benefits to the State seeking the diversion substantially outweigh the harm to existing uses in another State. We remand for specific factual findings relevant to determining a just and equitable apportionment of the water of the Vermejo River between Colorado and New Mexico.
It is so ordered.
CHIEF JUSTICE BURGER, with whom JUSTICE STEVENS joins, concurring.
This case arises from an understandably intense competition between two States over rights to a small, nonavigable, interstate river. Because on the record before it this
I emphasize that under our prior holdings these two States come to the Court on equal footing. See Kansas v. Colorado, 206 U.S. 46 (1907). Neither is entitled to any special priority over the other with respect to use of the water. Colorado cannot divert all of the water it may need or can use simply because the river's headwaters lie within its borders, Wyoming v. Colorado, 259 U.S. 419, 466 (1922). Nor is New Mexico entitled to any particular priority of allocation or undiminished flow simply because of first use. See, e. g., Colorado v. Kansas, 320 U.S. 383, 393 (1943). Each state through which rivers pass has a right to the benefit of the water but it is for the Court, as a matter of discretion, to measure their relative rights and obligations and to apportion the available water equitably. As the Court's opinion states, in the process of apportioning the water, prior dependence and inefficient uses may be considered in balancing the equities. But no state has any priority over any other state. It is on this understanding of the Court's holding that I join the opinion and the judgment.
JUSTICE O'CONNOR, with whom JUSTICE POWELL joins, concurring in the judgment.
The doctrine of prior appropriation includes the requirement that the appropriator's use of water be beneficial and reasonable. What is reasonable, of course, does not admit of ready definition, being dependent upon the particular facts and circumstances of each case. In this case, the Special Master has cast an accusatory finger at the Vermejo Conservancy District, concluding that "[t]he system of canals used to transport the water to the fields is inefficient." Report of Special Master 8.
Undoubtedly, there is evidence in the record indicating that large losses of water occur through seepage and evaporation in transporting waters of the Vermejo through open
Colorado would have the Court assess the Conservancy District's "waste" and "inefficiency" by a new yardstick — i. e., not by comparing the economic gains to the District with the costs of achieving greater efficiency, but by comparing the "inefficiency" of New Mexico's uses with the relative benefits to Colorado of a new use. The Special Master has succumbed to this suggestion. His recommendation that
Today the Court has also gone dangerously far toward accepting that suggestion. The Court holds, ante, at 186, that it is appropriate in equitable apportionment litigation to weigh the harms and benefits to the competing States. It does so notwithstanding its recognition, ante, at 187, that the potential benefits from a proposed diversion are likely to be speculative and remote, and therefore difficult to balance against any threatened harms, and its concession, ibid., that the equities supporting protection of an existing economy will usually be compelling.
In equitable apportionment litigation between two prior appropriation States concerning the waters of a fully appropriated river, this Court has never undertaken that balancing task outside the concrete context of either two established economies in the competing States dependent upon the waters to be apportioned
This case therefore highlights the restraint with which the Court should proceed in apportioning interstate waters between a State seeking a future use and a State with an existing economy dependent upon the waters to be apportioned. The Court can only invite litigation within its original jurisdiction if it permits one State to obtain a diversion for a new use upon that State's allegation that the second State is engaging in "wasteful" practices or that it can make "better" use of the waters, even if the second State's uses are entirely reasonable.
I do not suggest, of course, that the Court must blind itself to compelling evidence of waste by one State. Protection of existing economies does not require that users be permitted to continue in unreasonably wasteful or inefficient practices. But the Court should be moved to exercise its original jurisdiction to alter the status quo between States only where there is clear and convincing evidence, ante, at 188, n. 13, that one State's use is unreasonably wasteful. To allow Colorado a diversion upon a lesser showing comports neither with the equality of rights of the litigants before us, see Connecticut v. Massachusetts, 282 U.S. 660, 670 (1931), nor with the sparing use that should be made of the Court's equitable powers, see id., at 669. Further, such action would seriously undermine the Court's affirmation, ante, at 184, that priority of appropriation is the "guiding principle" in allocating waters between two prior appropriation States.
The Court's remand reflects its judgment that the paucity of the factual findings before us furnishes an inadequate basis
The prior appropriation doctrine and the riparian doctrine are the two basic doctrines governing the rights to the use of water. Under the prior appropriation doctrine, recognized in most of the Western States, water rights are acquired by diverting water and applying it for a beneficial purpose. A distinctive feature of the prior appropriation doctrine is the rule of priority, under which the relative rights of water users are ranked in the order of their seniority. Under the riparian doctrine, recognized primarily in the Eastern, Midwestern and Southern States, the owner of land contiguous to a watercourse is entitled to have the stream flow by or through his land undiminished in quantity and unpolluted in quality, except that any riparian proprietor may make whatever use of the water that is reasonable with respect to the needs of other appropriators.
Appropriative rights do not depend on land ownership and are acquired and maintained by actual use. Riparian rights, by contrast, originate from land ownership and remain vested even if unexercised. Appropriative rights are fixed in quantity; riparian rights are variable depending on streamflow and subject to the reasonable uses of others. See generally 1 R. Clark, Waters and Water Rights (1967); W. Hutchins, Selected Problems in the Law of Water Rights in the West (U. S. Dept. of Agriculture, Misc. Pub. No. 418, 1942); 1 W. Hutchins, Water Rights Laws in the Nineteen Western States (U. S. Dept. of Agriculture, Misc. Pub. No. 1206, 1971).
Vermejo Park diverts water primarily to irrigate land used to grow hay for its cattle operation. Kaiser Steel uses water primarily for its coal facilities. Phelps Dodge leases its rights to Kaiser Steel and to the C. S. Springer Cattle Co.
Because the State of Colorado has a substantial interest in the outcome of this suit, New Mexico may not invoke its Eleventh Amendment immunity from federal actions by citizens of another State. The portion of the Vermejo River in Colorado is owned by the State in trust for its citizens. Colo. Const., Art. XVI, § 5. While C. F. & I. will most likely be the primary user of any water diverted from the Vermejo River, other Colorado citizens may jointly use the water or purchase water rights in the future. In any event, Colorado surely has a sovereign interest in the beneficial effects of a diversion on the general prosperity of the State. Faced with a similar set of circumstances in Kansas v. Colorado, 206 U.S. 46, 99 (1907), we concluded that "[t]he controversy rises . . . above a mere question of local private right and involves a matter of state interest and must be considered from that standpoint."
We also conclude that Colorado is not barred by laches from seeking an equitable apportionment. For the reasons that we elaborate infra, at 186-188, we hold that under some circumstances the countervailing equities supporting a diversion of water for a future use in one State may justify the detriment suffered by existing users in another State. Therefore the mere fact that Colorado has no existing uses of the waters of the Vermejo River and that current users in New Mexico may suffer some detriment from a diversion does not bar Colorado's suit for an equitable apportionment for future uses. These circumstances, however, do bear on the burden of proof that Colorado must satisfy to justify the possible disruption of existing uses. See infra, at 187-188, and n. 13. A contrary conclusion is not dictated by Washington v. Oregon, 297 U.S. 517, 528 (1936), or Colorado v. Kansas, 320 U.S. 383, 394 (1943) (dictum), which merely require established users or holders of water rights to exercise diligence in protecting their rights and putting them to beneficial uses. See infra, at 184.
New Mexico must therefore bear the initial burden of showing that a diversion by Colorado will cause substantial injury to the interests of New Mexico. In this case New Mexico has met its burden since any diversion by Colorado, unless offset by New Mexico at its own expense, will necessarily reduce the amount of water available to New Mexico users.
The burden has therefore shifted to Colorado to establish that a diversion should nevertheless be permitted under the principle of equitable apportionment. Thus, with respect to whether reasonable conservation measures by New Mexico will offset the loss of water due to Colorado's diversion, or whether the benefit to Colorado from the diversion will substantially outweigh the possible harm to New Mexico, Colorado will bear the burden of proof. It must show, in effect, that without such a diversion New Mexico would be using "more than its equitable share of the benefits of a stream." Id., at 394. Moreover, Colorado must establish not only that its claim is of a "serious magnitude," but also that its position is supported by "clear and convincing evidence." Connecticut v. Massachusetts, supra, at 669. See also Colorado v. Kansas, supra, at 393; Washington v. Oregon, 297 U. S., at 522.
"We think [the] doctrine [of appropriation] lays on each of these States a duty to exercise her right reasonably and in a manner calculated to conserve the common supply. Notwithstanding her present contention, Wyoming has in fact proceeded on this line, for, as the proof shows, her appropriators, with her sanction, have provided and have in service reservoir facilities which are adapted for the purpose and reasonably sufficient to meet its requirements." 259 U. S., at 484-485 (emphasis added).
Wyoming v. Colorado, supra, does not represent an exception to the pattern stated in the text. The Court did not engage in any wholesale balancing of the relative harms and benefits to the two States from the proposed diversion. Rather, the Court imposed a very limited duty on Wyoming to make use of the storage facilities its appropriators already had in place, see n. 1, supra, for the purpose of calculating the dependable supply of water available to Wyoming. 259 U. S., at 484. The Court was thereby able to determine that the waters of the Laramie River were not fully appropriated and that a share of the waters was available for Colorado's proposed use.
"[W]hen we compare the amount of this detriment [to Kansas] with the great benefit which has obviously resulted to the counties in Colorado, it would seem that equality of right and equity between the two States forbids any interference with the present withdrawal of water in Colorado for purposes of irrigation." Ibid.
Quite clearly, the Court was not forced to speculate about the benefit and detriment of the diversion to the competing States.
Similarly, in Washington v. Oregon, supra, the Court was equipped to assess the balance of harm and benefit to the economies from the diversion at issue. Washington sought an injunction against Oregon's diversion of waters of the Walla Walla River for irrigation in Oregon. On the one hand, Oregon had an existing agricultural economy dependent upon irrigation from the Walla Walla. On the other hand, the evidence revealed that there would be absolutely no benefit to Washington in prohibiting Oregon's diversion during periods of water shortage; the nature of the river channel was such that even if the water was not diverted by Oregon users, it would be absorbed by the gravel beneath the channel and never reach Washington users. 297 U. S., at 522-523. The Court therefore concluded that "[t]o limit the long established use in Oregon would materially injure Oregon users without a compensating benefit to Washington users." Id., at 523.