Nebraska brought this suit in 1934 against Wyoming, invoking our original jurisdiction under Article III, Section 2 of the Constitution. 293 U.S. 523, 55 S.Ct. 115, 79 L.Ed. 635. Colorado was impleaded as a defendant. 296 U.S. 553, 56 S.Ct. 369, 80 L.Ed. 390. The United States was granted leave to intervene. 304 U.S. 545, 58 S.Ct. 1035, 82 L.Ed. 1519. Issues were joined. A Special Master, Honorable Michael J. Doherty, was appointed and hearings were held before him. The matter is before us on exceptions to his report.
The controversy pertains to the use for irrigation
purposes of the water of the North Platte River, a non-navigable stream. Nebraska alleged that Wyoming and Colorado by diversions of water from the river for irrigation purposes were violating the rule of priority of appropriation in force in the three States and depriving Nebraska of water to which she was equitably entitled. The prayer was for a determination of the equitable share of each State in the water and of the priorities of all appropriations in both States, and for an injunction restraining the alleged wrongful diversions. Wyoming denied the diversion or use of any water to which Nebraska was equitably entitled but joined in the prayer of Nebraska for an equitable apportionment. Colorado filed an answer, together with a cross-bill against Nebraska and Wyoming, which denied any use or threatened use of the water of the North Platte beyond her equitable share, and prayed for an equitable apportionment between the three States, excepting only the tributary waters of the South Platte and Laramie rivers. At the conclusion of Nebraska's case and again after all the evidence was in, Colorado moved to dismiss the suit on the ground that the evidence was insufficient to sustain any judgment in favor of, or against, any party. Colorado argues here that there should be no affirmative relief against her and that she should be dismissed from the case.
The North Platte River rises in Northern Colorado in the mountainous region known as North Park. It proceeds
in a northerly direction on the east side of the Continental Divide, enters Wyoming west of Cheyenne, and continues in a northerly direction to the vicinity of Casper. There it turns east across the Great Plains and proceeds easterly and southerly into and across Nebraska. About 40 miles west of the Nebraska line it is joined by the Laramie River. At North Platte, Nebraska, it is joined by the South Platte, forming the Platte River. It empties into the Missouri River at Plattsmouth, near the western border of Iowa. In North Park it is a rapid mountain stream. In eastern Wyoming it gradually broadens out, losing velocity. In western and central Nebraska its channel ranges from 3000 to 6000 feet; it frequently divides into small channels; and in times of low water is lost in the deep sands of its bed. Here it is sometimes characterized as a river 'two miles wide and one inch deep.'
There are six natural sections of the river basin: (1) North Park, Colorado, or more accurately Jackson County; (2) Colorado-Wyoming line to the Pathfinder Reservoir located between Rawlins and Casper, Wyoming; (3) Pathfinder Reservoir to Whalen, Wyoming which is 42 miles from the Nebraska line; (4) Whalen, Wyoming to the Tri-State Dam in Nebraska near the Wyoming-Nebraska line; (5) Tri-State Dam to the Kingsley Reservoir, west of Keystone, Nebraska; (6) Kingsley Reservoir to Grand Island, Nebraska.
The river basin in Colorado and Wyoming is arid, irrigation being generally indispensable to agriculture. Western Nebraska is partly arid and partly semi-arid. Irrigation is indispensable to the kind of agriculture established there. Middle Nebraska is sub-humid. Some crops can be raised without irrigation. But the lack of irrigation would seriously limit diversification. Eastern Nebraska, beginning at Grand Island, is sufficiently humid so as not to justify irrigation.
Irrigation in the river basin began about 1865, when some projects were started in eastern Wyoming and western Nebraska. Between 1880 and 1890 irrigation began on a large scale. Until 1909 storage of water was negligible, irrigation being effected by direct diversions and use. Prior to 1909 the development in Colorado and Wyoming was relatively more rapid than in Nebraska. Since 1910 the acreage under irrigation in Colorado increased about 14 per cent, that of Wyoming 31 per cent, and that of Nebraska about 100 per cent. The large increase in Nebraska is mainly attributable to the use of storage water from the Pathfinder Reservoir.