The appellant in this case invokes the doctrine that this court “may go behind the findings of a trial court, and consider all the evidence, decide on which side the preponderance thereof is, ascertain whether or not the proof justifies the findings and decree, and make such findings and decree as should be made in the judgment of the appellate court.” Whittaker v. Ferguson, 16 Utah 241.
We reaffirm that doctrine, and assert that this court- has full, power to review all questions of law and fact in equity cases, and if in our opinion the judgment of the lower court in such cases is not supported by the evidence, we may and will set- such judgment aside. Still, that doctrine is governed by the further principle that “when such eases have been regularly tried before a court of chancery, and if it has found on all material issues, we will not disturb such findings unless they are so manifestly erroneous as to demonstrate oversight or mistake which materially affects the substantial rights of the appellant.” McKay v. Farr, 15 Utah 261.
After a careful investigation of the record in the case before us, we have, however, absolutely failed to find any reason for setting aside the judgment of the lower court. In fact, it is difficult to see how that court, from the evidence adduced, could have reached a different conclusion. The testi*352mony effectually shows a continuous user of the waters of the creek by the defendants through their ditch constructed in 1879, and enlarged to its present capacity in 1880. It is true that since such time the irrigated area of land has increased, and that they did not at first have their entire premises prepared for cultivation; but from the commencement they continued with unabated vigor to clear land and irrigate the same year after year, extending their cultivation without enlarging their ditch, and during the irrigation season using all of the waters of said creek upon such lands. Naturally, and from the testimony, we know that when irrigation is first introduced upon arid land, it will moisten a much smaller area than it will after the soil has become saturated. Consequently, it is a matter of economy of time and increase of results to gradually extend the cultivated area below a stream, so far as the waters in such stream will permit, and continue to increase such cultivation as limited by the original intent of appropriation as evidenced by the size of the ditch and the conduct of the parties, until the full capacity of the stream has been attained, or until some other person has completed an appropriation of the surplus waters of the stream. So far as plaintiff’s efforts up to the commencement of this suit, in connection with the appropriation of the waters of this creek, are concerned, they consisted simply in the occupation, pasturing, clearing and plowing of lands near such creek, the user of certain springs upon a small part of the lands, the user of some of the water in 1881, after defendants’ user, the user of the water once in 1882, some indefinite user in 1884 (at a time when the water was high), and the unsuccessful user of water in the fall of 1886. Even that little diversion of water from the creek was by the plaintiff applied upon only eleven and a half acres of land, which also received irrigation from the so-called Big Springs. Under such circumstances we can not say that the *353plaintiff acquired any rights in the creek superior to tire rights of the defendants. . We see no reason why a settler in a new country may not appropriate the waters of an adjacent creek without having the lands he contemplates using the waters upon in a condition fit for irrigation at the time of his first diversion of such waters, at least until some other settler completes a successful, necessary and beneficial use of the then unappropriated waters of such creek. He is not confined to an appropriation simply for the amount of land irrigated during the first year of his diversion. The extent of an appropriation of water is determined by the reasonable necessity for the use of the water, by the intention of the appropriator, followed by a reasonable diligence in executing such intent, and by the beneficial purpose for which the appropriation is made. Hague v. Nephi Irrigation Co., 16 Utah 421.
Nor do we think that the evidence warrants the conclusion that defendants were estopped by their statements to plaintiff in May, 1885, from pursuing the full execution of their original intent of appropriation. At the time of making such statement, the entire lands of defendants were ready for cultivation and irrigation, and so far as the testimony relating to actual facts rather than the scientific guesses of an expert-shows, the entire waters of the creek were necessary for the successful irrigation of such lands. Besides, the entire waters were then actually being used upon the defendants’ lands, while at the same time plaintiff’s small, indefinite and intermittent user of the waters was of such small moment that even plaintiff himself stated that he would not bother with even an assertion of his right if defendants would desist from further extending their cultivated area. The testimony shows that no further extension of cultivated ground was made by defendants, except as they rounded off the corners of one of the *354fields. It is clear from tbe conversations themselves that at that time plaintiff had in view rather the imaginary possibilities of the waters of the creek than an interference with the then user of such waters by defendants. Even taking these conversations in the most favorable view for appellant,' there was absolutely no statement upon the part of the defendants of an intended abandonment of an existing right. It was merely an acquiescence in the plaintiff’s proposition that he would thereafter use all the waters of the -creek not then being used by defendants. ^It has frequently been held that an es-toppel will not arise simply from a breach of promise as to future conduct, or from a mere disappointment of expectations. The only case in which a representation as to the future can be held to operate as an estoppel is wherq it relates to an intended abandonment of an existing right. Union Mut. Life Ins. Co. v. Mowry, 96 U. S. 544; Allen v. Rundle, 50 Conn. 9.
The remainder of the errors assigned by appellant we do not feel called upon to decide, they not having been discussed by appellant in his brief.
We see no error in the record in this case, and the judgment of the lower court ought to be affirmed, and it is so ordered, and that the appellant pay the costs.
Baskin, J., concurs.