National Geographic : 1890 Jul
The IrrigationProblem in Montana. 227 falling about six feet per mile, a little more rapidly north of Big Timber, and decreasing in grade to the eastward. The gen eral elevation of this bench above the Yellowstone River varies from 600 feet north of Stillwater, to 300 feet north of Miles City, and includes about 11,000,000 acres, of which at least 5,225,000 acres are of the best quality for agricultural purposes and readily accessible by the great canal. In all this vast area there is not even sufficient water for the few horses and cattle which range on it, and they are compelled to congregate near the occasional pools and springs scattered at long intervals over it. From numerous examinations made hastily with aneroid and hand-level, it seems likely that a great canal can be taken from the Yellowstone, somewhere in the neighborhood of Livingston, or lower down the river, and led upon the summit of the bench with a diversion line not over 100 miles in length. Taken out at Livingston the canal would encounter no difficult construction, and would chiefly consist in earth excavation with very little rock work. It would require a few fills and flumes in crossing the larger side streams, such as the Little and Big Timber, Otter and Sweet Grass Creeks. It would reach the summit somewhere north of Merrill at an altitude of about 4,400 feet and thence could be conducted with an easy alignment eastward, with occa sional falls to loose grade. The water flowing in the Yellowstone River at Livingstone during the irrigating season this year averaged 2,300 cubic feet per second, which, with an allowance of thirty per cent. for loss by seepage and evaporation in the canal, would leave about 1,600 second feet at the point of utilization or sufficient to irrigate 160,000 acres. The average normal discharge from Yellowstone Lake is 700 second feet, and a dam about 300 feet long and less than ten feet high, constructed below the outlet of the lake, would store the outflow from October to May, inclusive, eight months, a total including flood discharges of at least 600,000 acre feet, an amount which, allowing for loss by evaporation in the lake, and by seepage and evaporation in the canal, would irrigate 425,000 acres, in addition to the 160,000 acres previously mentioned. Besides this volume probably half as much more can be readily stored on the Lamar and Gardner Rivers, and the other branches of the Yellowstone which join it above Livingston, bringing the total area of reclaimed land to nearly 1,000,000 acres.