“ In contending for a larger finding, Colorado points to the issue by Wyoming's state engineer of permits, so called, for appropriations in excess of that amount, and insists that these permits constitute solemn adjudications by that officer that the supply is adequate to cover them. But in this the nature of the permits is misapprehended. In fact and in law they are not adjudications, but mere licenses to appropriate, if the requisite amount of water be there. As to many nothing ever is done under them by the intending appropriators. ”

“ Colorado further answers that she can accomplish more with the water than Wyoming does or can; that she proposes to use it on lands in the Cache la Poudre valley; and that they with less water will produce more than the lands in the portion of the Laramie valley known as the Laramie Plains. It is true that irrigation in the Poudre valley has been carried to a higher state of development than elsewhere in the Rocky Mountain region, and that the lands of that valley lieat a lower altitude than do those in the Laramie Plains, and generally are better adapted to agriculture. ”

“ No doubt the natural flow can be materially conserved and equalized by means of storage reservoirs, but this has its limitations, both financial and physical. The construction of reservoirs of real capacity is attended with great expense, and unless an adequate return reasonably can be foreseen the expenditure is not justified and will not be made. The years of high water and those of low do not alternate. Often several of the same kind follow in succession. The evaporation of stored water in Colorado and Wyoming is from 5 to 6 feet per year. ”

“ It would be similar to financial proposition of people in Florida preparing to heat their houses in the same manner as those in the northern part of the United States. For years of unusually high flow in the Poudre river, conservation works, to utilize the excess waters in that stream, would have to count on carrying water over more than one year. The utilization of this water means the presence of population on the land; that population must have a living from year to year, and they are not justified in going out on the land and settling to raise a crop only once in three or four years. ”

“ The evidence shows that the Wyoming appropriations having priorities senior to the one in Colorado, and which are dependent on the available supply before named, cover 181,500 acres of land, and that the amount of water appropriated and reasonably required for the irrigation of these lands is 272,500 acre-feet. A much larger amount is claimed, but our finding restricts the amount to what the evidence shows is reasonably required, which is 1 acre-foot per acre for the larger part of the lands, 2 acre-feet per acre for a part, and 2 1/2 acre-feet per acre for the remainder. ”

“ Colorado, wherein the relative rights of the two states, the United States, certain Kansas riparians, and certain Colorado appropriators and users in and to the waters of the Arkansas river, an interstate stream, were thought to be involved. Congress was solicitous that all questions respecting interstate streams thought to be involved in that litigation should be left to judicial determination unaffected by the act-in other words, that the matter be left just as it was before. ”

“ Both Colorado and Wyoming are in the arid region, where flowing waters are, and long have been, commonly diverted from their natural channels and used in irrigating the soil and making it productive. For many years some of the waters of the Laramie river have been subjected to such diversion and use, part in Colorado and part in Wyoming. ”

“ Then companies with large capital constructed extensive canals and occasional tunnels, whereby water was carried to lands remote from the stream and supplied, for hire, to settlers who were not prepared to engage in such large undertakings. Ultimately, the demand for water being in excess of the dependable flow of the streams during the irrigation season, reservoirs were constructed, wherein water was impounded when not needed and released when needed, thereby measurably equalizing the natural flow. ”

“ This table shows that during 30 years-1884 to 1913-the yearly flow of the Cache la Poudre ranged from 151,636 to 666,466 acre-feet, that in 16 of the 30 it fell below the average, and that 8 of the 16 were in immediate succession. Obviously it is not financially practicable, even by means of reservoirs, to equalize the flow of a stream subject to such variation, so that it will have a fairly constant and dependable flow at the average of all years. ”

“ Their natural flow is small. As to some it is all used under old appropriations, as to some it is partly used under such appropriations, and as to some it is only seasonal; the channels being dry much of the year. Some creeks spoken of in Colorado's evidence as tributaries are otherwise shown not to be such, but to deliver their waters into lakes or ponds not connected with either of the principal streams. Colorado's evidence also takes into account some tributaries which discharge into the Laramie below the points of diversion of all the Wyoming appropriations with which we are concerned. ”

“ In practice they proceed on the view that within limits, financially and physically feasible, a fairly constant and dependable flow materially in excess of the lowest may generally be obtained by means of reserviors adapted to conserving and equalizing the natural flow, and we regard this view as reasonable.
But Wyoming takes the position that she should not be required to provide storage facilities in order that Colorado may obtain a larger amount of water from the common supply than otherwise would be possible. ”

“ Both states have vast plains and many valleys of varying elevation, where there is not sufficient natural precipitation to moisten the soil and make it productive, but where, when additional water is applied artificially, the soil becomes fruitful-the reward being generous in some areas and moderate in others, just as husbandry is variously rewarded in states where there is greater humidity, such as Massachusetts, Virginia, Ohio, and Tennessee. ”

“ When the evidence was taken, in 1913 and 1914, the Laramie had not been gaged so thoroughly nor for so long a period as had the Cache la Poudre. Such gaging as had occurred had been done at different places in different periods, partly by the United States Geological Survey, partly by Colorado, and partly by Wyoming. Some of the gaging stations were in Colorado, but most were in Wyoming. The latter included Woods, nine miles north of the state boundary, and the Pioneer Dam, four miles north of Woods. The evidence centered largely around the flow and gaging at these places. ”

“ When this suit was brought, the two corporate defendants, acting under the authority and permission of Colorado, were proceeding to divert in that state a considerable portion of the waters of the river and to conduct the same into another watershed, lying wholly in Colorado, for use in irrigating lands more than 50 miles distant from the point of diversion. The topography and natural drainage are such that none of the water can return to the stream or ever reach Wyoming. ”

“ The population has to exist and stay on the ground. From standpoint of investment, conservation of flow such as extreme flow of 1884 would be impractical to the extent that it exceeded the ordinary high year. ”

“ Peterson, we had occasion to consider the respective rights of miners to running waters on the mineral lands of the public domain; and we there held that by the custom which had obtained among miners in the Pacific states and territories, the party who first subjected the water to use, or took the necessary steps for that purpose, was regarded, except as against the government, as the source of title in all controveries respecting it ”

“ Average 189,925, including all years but 1899.
It of course is true that the variation in the flow will not always be just what it was in the years covered by the table, and yet the data obtained by the gaging and measurements in those years show better than anything else what reasonably may be expected in the future. We recognize that the problem which the table is intended to illustrate is not a simple one and that to work it out will involve the exercise of both skill and care. ”

“ And still another of her witnesses, referring to the unused waters of the Poudre in years of high flow and also to what is contemplated by the defendants in respect of the Laramie, said:
'The really dependabel water supply of the district [2] will come from the Laramie river; the amount secured from the Poudre rixer fluctuation greatly and being used to augment the supply from the Laramie. There will be years when the supply from the Poudre river and its tributaries will be practically nothing. ”

“ This gives a total of 213,241 acre-feet for 1912 and 113,593 acre-feet for 1913. Tested by the flow of these years, the available supply would be 163,417 acrefeet; that is to say, on that basis the excess in 1912 would match the deficiency in 1913. But a survey of more than two years is essential in arriving at a fair conclusion respecting the available supply. A year of low flow is not always preceded by one of high or moderate flow, as was the case with 1912 and 1913. ”

“ In such cases there is no appropriation, and even in others the amount of the appropriation turns on what is actually done under the permit. In late years the permits relating to these streams have contained a provision, saying:
'The records of the state engineer's office show the waters of [the particular stream] to be largely appropriated. ”

“ For further illustration we have taken the average of the 26 years remaining after excluding the 4 described by the witness as extraordinary (these being left to take the average of the others) , and on that basis have made a computation of the excess and deficiency, which is shown in the fourth column of the table. ”

“ St. Rep. 914; Farm Investment Co. v. Carpenter, 9 Wyo. 110, 61 Pac. 258, 50 L. R. A. 747, 87 Am. St. Rep. 918; Willey v. Decker, 11 Wyo. 496, 73 Pac. 210, 100 Am. St. Rep. 939; Johnston v. Little Horse Creek Irrigating Co., 13 Wyo. 208, 79 Pac. 22, 70 L. R. A. 341, 110 Am. St. Rep. 986.
As the United States possessed plenary authority over Colorado and Wyoming while they were territories and has at all times owned the public lands therein, we turn next to its action. ”