This suit is the latest of a series of litigations between Kansas or her citizens, and Colorado, or her citizens, concerning their respective rights to the beneficial use of the waters of the Arkansas River.
The river has its origin in central Colorado, and is a mountain torrent for 130 miles to a point near Canon City where it enters a foothill region ending near Pueblo. Thence it traverses the high plains of eastern Colorado and western Kansas. In the areas mentioned the stream is non-navigable.
In 1901 Kansas brought suit against Colorado in this court for an injunction restraining the latter from diverting, or permitting anyone under her authority to divert, waters of the river within Colorado, and for general relief. State of Kansas v. Colorado, 206 U.S. 46, 27 S.Ct. 655, 51 L.Ed. 956. Kansas in her bill alleged that the waters of the river had been used for irrigation in her western counties and that, after establishment of these uses, Colorado began systematically to appropriate and divert them between Canon City and the Kansas state line for irrigating non-riparian arid lands; that, by 1891, all the natural flow, and much of the flood waters, had been appropriated in Colorado so that the average flow had been greatly reduced and the natural flow completely cut off.
Colorado replied that the stream was not continuous except at times of flood; that, in a state of nature, its bed east of Pueblo was frequently dry; that Colorado and her citizens had diverted and used only the perennial flow above Canon City and what had been done in effect conserved water for delivery into Kansas. She denied she had substantially diminished the flow of the river at the state line. She asserted she was entitled to consume the entire flow; but alleged that, in any view, her total appropriations did not amount to an infringement of Kansas' rights calling for judicial interference.
The court denied Kansas' contention that she was entitled to have the stream flow as it flowed in a state of nature. It denied Colorado's claim that she could dispose of all the waters within her borders, and owed no obligation to pass any of them on to Kansas. It declared that as each state had an equality of right each stood before the court on the same level as the other; that inquiry was not confined to the question whether any portion of the river waters were withheld by Colorado but must include the effect of what had been done upon the conditions in the respective states; and that the court must adjust the dispute on the basis of equality of rights to secure, so far as possible, to Colorado, the benefits of irrigation, without depriving Kansas of the benefits of a flowing stream. The measure of the reciprocal rights and obligations of the states was declared to be an equitable apportionment of the benefits of the river. The court added that, before the developments in Colorado consequent upon irrigation were to be destroyed or materially affected, Kansas must show not merely some technical right but one which carried corresponding benefits.
On examination of the proofs, the court concluded that diversions authorized by Colorado embraced more water than the total flow at Canon City. It found, however, that no clear showing was made as to what surplus water, if any, was contributed by the tributaries below that point or as to the proportion of the diverted water returned to the river by seepage. The opinion described the diversions in each state, analyzed the use made of the water and the benefits derived from it in each, considered population tables and agricultural statistics bearing upon the growth of the communities adjacent to the river in each, and stated conclusions, now material, as follows: That the result of Colorado's appropriations had been beneficial reclamation of many acres; that, while the influence of Colorado's diversions had been of perceptible injury to portions of the Arkansas valley in Kansas, yet to the great body of the valley the diminution of flow had worked little, if any, detriment; that regarding the interests of both states, and the right of each to receive benefit through irrigation and otherwise from the waters of the stream, the court was not satisfied that Kansas had made out a case entitling it to a decree. The court added that if depletion by Colorado continued to increase there would come a time when Kansas might justly say that there was no longer an equitable distribution of benefits and might rightly call for relief against Colorado and her citizens. Accordingly the bill was dismissed without prejudice to future action by Kansas. The taking of evidence ended June 16, 1905, and the decision of the court was announced May 13, 1907.