dissenting.
I dissent.
By substituting its interpretation of the Flood Control Act for that of the Secretary of the Interior, the majority misconceives our limited role when reviewing an agency’s construction of a statute that it administers. As the Supreme Court has re*288peatedly emphasized, “[a]n agency’s construction of a statute it is charged with enforcing is entitled to deference if it is reasonable and not in conflict with the expressed intent of Congress.” United States v. Riverside Bayview Homes, Inc., 106 S.Ct. 455, 461, 88 L.Ed.2d 419 (1985).1 The Secretary of the Interior reasonably construed section 9(c) of the Flood Control Act to provide that federal reclamation law governs the administration of irrigation water stored in the Oahe Reservoir. I would therefore reverse the district court’s contrary holding and decide the remaining issues presented in this appeal.
Section 9(c) of the Flood Control Act provides that “reclamation and power developments to be undertaken by the Secretary of the Interior * * * shall be governed by the Federal Reclamation Laws.” The Secretary of the Interior interpreted “reclamation developments” within this provision to include irrigation water stored within multipurpose reservoirs operated by the Army Corps of Engineers on the Missouri River. The Secretary concluded that the applicable reclamation laws authorized him to market the irrigation water for industrial use.2 Pursuant to section 9(c) and the reclamation laws, the Secretary executed contracts to supply ETSI with irrigation water held within the Oahe Reservoir, a multipurpose reservoir on the Missouri River operated by the Corps.
The thoroughness and consistency of an agency’s reasoning are factors that bear upon the amount of deference to be given the agency’s interpretation. See Federal Election Commission v. Democratic Senatorial Campaign Committee, 454 U.S. 27, 37, 102 S.Ct. 38, 44-45, 70 L.Ed.2d 23 (1981). The Secretary’s interpretation of section 9(c) was first asserted by the Solicitor of the Interior Department in a 1974 opinion. In 1975, the Secretary of the Interior formally adopted the interpretation in a Memorandum of Understanding entered into with the Secretary of the Army. The Memorandum stated that the Secretary of the Interior could market excess irrigation water stored in the Army-controlled reservoirs on the main stem of the Missouri River. The parties informed a congressional subcommittee that the Secretary of the Interior gained such authority from the reclamation laws, which they contended applied to the stored irrigation water under section 9(c) of the Flood Control Act. Hearings on the Sale of Water from the Upper Missouri River Basin by the Federal Government for the Development of Energy, 94th Cong., 1st Sess. 1, 5 (1975). The Memorandum expired in 1978.3
Since 1975, therefore, the Secretary of the Interior has consistently interpreted “reclamation developments” within section 9(c) to include irrigation water stored in multipurpose reservoirs on the Missouri River. We must give great weight to this long-standing and thoroughly reasoned construction. Consequently, we review the Secretary’s interpretation only to determine whether it reflects a reasonable construction of section 9(c) in light of the language, policies, and history of the Flood Control Act of 1944. Riverside Bayview Homes, 106 S.Ct. at 461-62.
*289The Secretary’s interpretation certainly represents a permissible construction of the language of the Flood Control Act. The Act nowhere defines “reclamation developments” as used in section 9(e). Further, it does not explicitly delegate control over stored irrigation and reclamation water to either the Army or the Interior. Indeed, the Act never specifically mentions such water. The Act therefore fails to reveal any clear and unambiguous intention of Congress to exclude irrigation water from the meaning of “reclamation * developments to be undertaken by the Secretary of the Interior” in section 9(c).
Despite an inability to identify the precise meaning that Congress attached to “reclamation developments,” the majority asserts that several provisions of the Act reflect Congress’ definite intent to foreclose the Secretary’s interpretation. These provisions, however, also can be read consistently with section 9(c) as construed by the Secretary. Language open to such varying interpretations cannot be said to reveal Congress’ “clear and unambiguous” intent, as the majority contends.4
Not only the words but also the legislative history of the Act fall far short of showing any unambiguous congressional intent to bar the Secretary of the Interior from asserting jurisdiction over irrigation water stored in Army reservoirs. See Chemical Manufacturers Ass’n v. Natural Resources Defense Council, Inc., — U.S.-, 105 S.Ct. 1102, 1110, 84 L.Ed.2d 90 (1985) (“After examining the wording and legislative history of the statute, we agree with [the agencies] that the legislative history itself does not evince an unambiguous Congressional intention to forbid [the agencies’ interpretation].”). Indeed, the evolution of the Flood Control Act strongly supports the interpretation of section 9(c) advanced by the Secretary of the Interior.
In the early forties, Congress requested the Army Corps of Engineers and the Interior’s Bureau of Reclamation to develop plans for alleviating water problems facing the states in the Missouri River Basin. The Corps’ study, the Pick Plan, focused primarily on reducing the flooding problems of the downstream states without depriving them of the Missouri’s navigation benefits. See H.R.Doc. 475, 78th Cong., 2d •Sess. (1944). In contrast, the Bureau of Reclamation’s study, the Sloan Plan, directed most of its attention to guaranteeing a ready supply of irrigation water for the frequently drought-stricken states in the upper Missouri Basin. See S.Doc. 191, 78th Cong., 2d Sess. (1944).
Both plans ultimately advised Congress to authorize construction of a series of dams and reservoirs along the Missouri River and its tributaries. Because the Corps and the Bureau of Reclamation represented different interests, their plans differed in matters such as the placement and size of the projects. Both agencies agreed, however, that the reservoirs should be administered such to “contribute most significantly to the welfare and livelihood of the largest number of people.” H.R.Doc. 475 at 7; see S.Doc. 191 at 10.
The agencies suggested that, to achieve the greatest benefits, the reservoirs should serve a number of purposes, including flood control, navigation, and irrigation. *290H.R.Doc. 475 at 7; S.Doc. 191 at 10. And to assure that both the upstream and downstream states would share in the reservoirs’ benefits, the agencies proposed that the Secretaries of the Army and Interior share in the reservoirs’ control.
Under this concept of coordinate jurisdiction, the agency with the dominant interest in the reservoir would control its daily operations. For example, the Army Corps would operate those reservoirs intended primarily for flood control and navigation. To the extent that the Secretary of the Interior also had an interest in the reservoirs, the regulations of the Secretary would govern the administration of that interest. Therefore, the Secretary’s regulations would control the administration of irrigation water stored in all multipurpose reservoirs.5
Because the Pick and Sloan Plans differed in some respects, Congress directed that a committee representing both agencies prepare a report reconciling the differences. In the resulting “Pick-Sloan Compromise,” the only provision discussing control of the reservoirs reiterated the need for shared jurisdiction between the agencies:
3. It was possible to bring into agreement the plans of the Corps of Engineers and the Bureau of Reclamation by recognizing the following basic principles:
(a) The Corps of Engineers should have the responsibility for determining main stem reservoir capacities and capacities of tributary reservoirs for flood control and navigation.
(b) The Bureau of Reclamation should have the responsibility for determining reservoir capacities on the main stem and tributaries of the Missouri River for irrigation, the probable extent of future irrigation, and the amount of stream depletion due to irrigation development.
S.Doc. 247, 78th Cong., 2d Sess. 1 (1944).
The Pick, Sloan, and Pick-Sloan Plans thus assumed that Interior regulations would govern irrigation water stored in multipurpose dams, and Army regulations would control water stored for flood control and navigation. Congress adopted the Pick and Sloan Plans, as reconciled in the Pick-Sloan Compromise, in section 9(a) of the Flood Control Act. Neither the Act nor its legislative history clearly rejects the plans’ underlying assumption of coordinate jurisdiction. The Secretary could therefore reasonably conclude that “reclamation developments” within section 9(c) include irri*291gation water stored in the main stem reservoirs.6
As the Supreme Court recently observed, effectuating congressional intent will occasionally yield anomalies. Federal Reserve System v. Dimension Financial Corp., — U.S. -, 106 S.Ct. 681, 689 n. 7, 88 L.Ed.2d 691 (1986). Although nothing prohibits Congress from adopting unwise legislation, id., we must not assume that Congress did so unless compelled by a clear expression of congressional intent. The majority’s interpretation of the Flood Control Act produces some very curious results. It leaves the irrigation water stored in the main stem reservoirs without a governing agency or law. See supra at 277 n. 4. Consequently, the irrigation water stored in the vast Oahe Reservoir will sit unused and useless.7 The Department of the Interior, representative of the irrigation interests of the upper basin states, will have no voice in the administration of the excess irrigation water. Instead, the Army Corps of Engineers, whose primary interests are in flood control and navigation, the same primary interests as the downstream states, will unilaterally regulate water in the largest federal reservoir in the Missouri Basin — a reservoir located in an upstream state and designed with the anticipation that its major consumptive use would be irrigation. Surely Congress did not intend such incongruous consequences.
In the absence of a congressional directive to the contrary, we must defer to the Secretary’s reasonable interpretation of section 9(c) of the Flood Control Act. See Chemical Manufacturers Ass’n v. Natural Resources Defense Council, Inc., 105 S.Ct. at 1112. This deference seems particularly apt here, where the Army Corps of Engineers asserts no objection to the actions taken by the Secretary of the Interi- or. We should uphold the Secretary’s permissible construction, not indulge in judicial creativity by choosing between competing interpretations. I would therefore reverse the district court’s ruling that reclamation law does not apply to the irrigation water stored in the Oahe Reservoir,8 and address those remaining issues not decided by the majority because of its disposition of this appeal.
. We must defer to an agency's reasonable interpretation even though it determines the agency’s jurisdiction under the statute. See United States v. Riverside Bayview Homes, Inc., — U.S.-, 106 S.Ct. at 461-66, 88 L.Ed.2d 419 (1985).
. The district court did not determine and we do not decide whether the Secretary correctly construed his powers under the reclamation laws. We consider only whether the Secretary reasonably concluded that the reclamation laws govern the administration of the stored irrigation water.
. The majority states that the Memorandum of Understanding has no relevancy in this action because it had expired when the Secretary executed the ETSI contract. See Majority Opinion at 279 n. 9. However, the Memorandum does show that the Secretary of the Interior has consistently interpreted section 9(c) of the Flood Control Act to require application of reclamation laws to irrigation water stored in the Army-controlled main stem reservoirs. To that extent, therefore, the Memorandum of Understanding has great relevance to our examination of the Secretary's authority to enter the ETSI contract.
. The majority, for example, finds great significance in Congress’ specific delegation to the Army of control over water stored for flood control and navigation (section 7) and over surplus water not allocated for any use (section 6). See Majority Opinion at 285-86. The majority concludes that Congress would have also specifically granted the Secretary of the Interior jurisdiction over stored irrigation water had it intended the Secretary to exercise such control.
If we followed the majority's reasoning to its logical conclusion, no agency has jurisdiction over irrigation water stored in Army reservoirs because Congress did not expressly delegate such authority. Such a rigid and narrow reading of the Act finds little support in the Act’s language and no support in its legislative history. An equally reasonable explanation for the lack of any specific delegation of jurisdiction to the Secretary of the Interior is that Congress believed that such jurisdiction was already sufficiently delegated in section 9(c). This explanation not only gives the Act internal symmetry and consistency, but also supports the interpretation of section 9(c) advanced by the Secretary of the Interior.
. The Chief of Engineers summarized the mechanics of this shared jurisdiction in a letter accompanying the submission of the Pick Plan to Congress:
Tributary reservoirs should, when advisable from the standpoint of basin-wide development, be constructed, operated, and maintained by the agency with the dominant interest under existing law. It is essential, however, that the main stem projects be built, operated, and maintained by the Corps of Engineers, and that utilization of storage reserved for flood control in all multiple-purpose reservoirs or tributaries be in accordance with regulations prescribed by the Secretary of War. * * * Conversely, utilization of storage reserved for irrigation in all multiple-purpose reservoirs should be in accordance with regulations prescribed by the Secretary of the Interior.
H.R.Doc. 475 at 3-4.
The Sloan Plan echoed this division of authority:
All reservoirs where flood control and navigation are dominant should be operated by the Corps of Engineers, and where flood control and navigation functions are minor, the reservoir should be operated in accordance with regulations of the Corps so far as flood control and navigation are concerned. All irrigation features should be operated by the Bureau of Reclamation or its agents. All reservoirs in which irrigation, restoration of surface and ground waters, or powers is dominant, should be operated by the Bureau of Reclamation. Where these functions are minor, the reservoirs should be operated under regulations of the Bureau of Reclamation so far as such functions are concerned.
S.Doc. 191 at 11. In a letter commenting on the Sloan Plan and accompanying its filing with Congress, the Army Corps again emphasized that "[i]n all reservoirs, utilization of storage for flood control should be in accordance with regulations prescribed by the Secretary of War and utilization of storage for irrigation should be in accordance with regulations prescribed by the Secretary of the Interior.” Id. at 8.
. The majority contends that Congress’ failure to adopt two proposed provisions that specifically provided that reclamation law applied to irrigation water strongly suggests that Congress did not intend for such law to apply. Once again, however, Congress’ failure to pass the legislation can be also construed consistently with the Secretary’s position, and therefore hardly constitutes compelling evidence of its intent.
. An essential difference between the majority and the dissent centers on whether water allocated for irrigation, but not yet used for that purpose, becomes "surplus water” under the Army’s control pursuant to section 6 of the Flood Control Act. Although the majority contends that the stored irrigation water constitutes "surplus water,” Majority Opinion at 30 n. 20, the legislative history of section 6 indicates otherwise. The debates on section 6 indicate that Congress may have intended "surplus water” to include only water not allocated for other uses. See, e.g., 90 Cong.Rec. 4133. The water here in question from the Oahe Reservoir is allocated for irrigation, and therefore apparently does not constitute “surplus water” under the Army’s control.
. The majority observes that an "additional problem” exists because no specific allocation has been made concerning the amount of irrigation water stored in the Oahe. Majority Opinion at 281 n. 15. The design of the reservoir as authorized by Congress, however, expressly stated that the Oahe Reservoir would contain water to irrigate 750,000 acres of land, as well as additional storage for flood control and other uses. See S.Doc. 247, 78th Cong., 2d Sess. 3 (1944) ("The Pick-Sloan Compromise") (codified at section 9(a) of the Flood Control Act of 1944). No party to this appeal contends that the 20,000 acre-feet of water per year included in the ETSI contract would even approach exhausting this allocation.