(dissenting):
I dissent because I believe the majority opinion answers the wrong question and *1082unwittingly reverses a long-standing and important rule governing the function of the state engineer in approving change applications.
In effect, the majority defines the central issue as whether the expert’s affidavits raise any “genuine issue of material fact” as to whether the proposed changes can be made without impairing vested water rights? If that were the issue, I would concur, since the majority opinion conclusively demonstrates that there are issues of fact on that question.
But this is not a case where the district court was called upon to adjudicate priorities or other vested rights. This is evident from the majority’s concession that the issues before the district court in this case are strictly limited to those properly before the state engineer, because it is well settled that the state engineer cannot adjudicate the priority or extent of vested rights. E.g., Daniels Irrigation Co. v. Daniel Summit Co., Utah, 571 P.2d 1323, 1324 (1977); East Bench Irrigation Co. v. State, 5 Utah 2d 235, 240, 300 P.2d 603, 607 (1956); Whitmore v. Murray City, 107 Utah 445, 450-51, 154 P.2d 748, 750 (1944); United States v. District Court of Fourth Judicial District, 121 Utah 18, 242 P.2d 774 (1952).
What is at issue in this case is the propriety of an administrative decision by which the state engineer authorized a change in the place of diversion or use or the manner of use of water owned by the applicants. That decision is governed by a different standard than the district court employs in determining whether to grant summary judgment in an adjudication of vested rights.
U.C.A., 1953, § 73-3-3 provides that “no such change shall be made if it impairs any vested right without just compensation.” Contrary to the approach of the majority, that statute does not require an adjudication of vested rights in order to approve a change application. In the context of Utah water law and the assigned function of the state engineer, a succession of cases has applied the direction of § 73-3-3 in terms of whether there is “reason to believe” that the change can be made without impairing vested rights. This is the practical equivalent of a probable cause determination in a criminal case.
Under our cases, the state engineer (or the district court in a de novo appeal from the state engineer’s decision) must approve a change application “if the tribunal concludes that there is reason to believe that no existing right will thereby be impaired.” United States v. District Court of Fourth Judicial District, 121 Utah 18, 24, 242 P.2d 774, 777 (1952). This “reason to believe” rule is repeatedly stated in this same opinion. 121 Utah at 20-21, 242 P.2d at 775-76. It is also stated in the earlier opinion in the same case, United States v. District Court of Fourth Judicial District, 121 Utah 1, 10-12, 238 P.2d 1132, 1136-37 (1951), and in a succession of later cases. Piute Reservoir & Irrigation Co. v. West Panguitch Irrigation & Reservoir Co., 13 Utah 2d 6, 7-8, 10, 367 P.2d 855, 856, 858 (1962); Salt Lake City v. Boundary Springs Water Users Association, 2 Utah 2d 141, 143-44, 270 P.2d 453, 455 (1954).
The meaning, intent, and function of the “reason to believe” rule are best explained in United States v. District Court of Fourth Judicial District, 121 Utah at 11-12, 238 P.2d at 1137, as follows:
From these decisions and the cases cited above, it is clear that the district court’s judgment can only cover the issues subject to determination by the Engineer and that the effect of such judgment is the same as it would have been if the Engineer had reached the same conclusion in the first instance. The Engineer in granting an application does not determine that the applicant’s rights are prior to the rights of the protestant but only finds there is reason to believe that the application may be granted and some water beneficially used thereunder without interfering with the rights of others .... Such a decision is administrative in *1083nature and purpose and the decision of the court on review, except for the formalities of the trial and judgment is of the same nature and for the same purpose. The object of the engineer’s office is to maintain order and efficiency in the appropriation, distribution and conservation of water and to allow as much water to be beneficially used as possible. So construed, the law provides a period of experimentation during which ways and means may be sought to make beneficial use of more water under the application before the rights of the parties are finally adjudicated. If we were to finally adjudicate applicant’s right to change or to appropriate water at the time that such application was rejected or approved, he would get only such rights as he could establish by a preponderance of the evidence that he could use beneficially without interfering with the rights of others and in such hearing he would not have the benefit of any opportunity to experiment and demonstrate what he could do. Such a system would cut off the possibility of establishing many valuable rights without a chance to demonstrate what could be done. [Emphasis added.]
Accord, Eardley v. Terry, 94 Utah 367, 77 P.2d 362 (1938).
It is abundantly clear from the order and summary judgment in this case that all the district court held was that there was “reason to believe that said Change Applications can be approved on the same terms and conditions as set forth in the ... Decisions of the State Engineer thereon without impairing the existing water rights of plaintiffs.” (Emphasis added.) In so ordering, the district court phrased the issue correctly. And, in view of the content of the Mower and Walker affidavits, there was no error in the court’s resolution of that issue. Its order should be affirmed.
The majority reverses the district court because the Mower and Walker affidavits were contradicted by Neeley. But when the determination is “probable cause” or “reason to believe,” the question of “whether there is a genuine issue of material fact” is a contradiction in terms. In determining whether there is “reason to believe” a proponent’s submission, the fact that it has been contradicted is not disabling. A probable cause determination is not the time to resolve contradictions. That comes later, in the formal adjudication. In this case, that will be a proceeding to adjudicate whether vested rights are in fact being impaired.
A change application can be denied by the state engineer or by the court on appeal from the engineer’s decision, but not simply on the basis of what the majority calls “the production of evidence which controverts the existence of ‘reason to believe.’ ” That standard would subvert the purpose of this preliminary administrative determination. A change application should only be denied when, after resolving all contradictions in favor of the proponent of change, the evidence offered is so deficient that it provides no reason to believe that the proposed change could be made without impairing rights. Piute Reservoir & Irrigation Co. v. West Panguitch Irrigation & Reservoir Co., supra. This is not such a case.
By reversing the district court and remanding this case for trial to resolve issues of fact on the existence of “reason to believe,” the majority effectively reverses the “reason to believe” test and telescopes an interlocutory administrative determination on a change application into a mini-adjudication of vested rights. Seen in a larger context, this is just one more instance where the law is being changed in a manner that will make it more complicated and require more time, more money, and more lawyers and judges for its administration. See Bok, “A Flawed System,” Harvard Magazine, May-June 1983, at 38, 42-44. Change applications previously handled by laymen and technical experts will now need to be administered by lawyers and judges in a preliminary adversary proceeding in any case where an opponent files contradictory material. If the change application is ap*1084proved, the opponent can later compel a second adversary proceeding to adjudicate the actual impairment of vested rights.
The adversary determination of infringements on vested rights should take place only once, after a change application has been approved administratively upon a preliminary showing of “reason to believe.” Then the adjudication of vested rights can be made on the basis of evidence tied to experience, rather than upon the conflicting estimates that will be bruited about in the preliminary trial required by the majority in this case.
HALL, C.J., concurs in the dissenting opinion of OAKS, J.