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 occasional 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.
There are many similar and even better opportunities for irrigation development, such as the construction of a canal from the West Gallatin River near Bozeman. This canal would require no expensive diversion line, as its waters would become immediately available at the headworks, and by appropriating the 500 second feet of water flowing in the river, would reclaim at a minimum cost 50,000 acres, or twice the amount of land now cultivated there. Storage on the Upper Gallatin River would greatly increase the amount of reclaimed land.
Storage reservoirs can be easily constructed on the headwaters of the Beaver Head River, whereby at least 150,000 acres could be added to the 25,000 acres now under cultivation in the Beaver Head Valley near Dillon.
A canal requiring no diversion line can be taken out on the east side of the Missouri River near Toston, which will irrigate all of the good land in the Missouri Valley, at least 100,000 acres. This canal would require some fills and aqueducts in crossing the various side steams such as Deep and Duck Creeks, and Confederate Gulch.
Detailed surveys have been made during the past summer on the Sun River which indicate that storage will add some 250,000 acre feet to the amount of water in that stream now available for irrigation. There are at least 600,000 acres of good agricultural land between the Dearborn, Sun, and Teton Rivers, which must forever remain barren of cultivated products unless provided with water by means of storage on these streams, and the surveys above alluded to indicate that by this means 160,000 acres of this land can be reclaimed by the Sun River alone.
Mention might be made to many more similar projects, such as the construction of a simple canal from the Missouri River to irrigate Chestnut Valley, south of Great Falls, whereby 120,000 acres would be reclaimed; or one from the Upper Madison River whereby 230,000 acres of the Madison Valley might receive water, but the foregoing will suffice to show the possibilities of irrigation development in Montana.
It would be doing the resources of a great and vast area of Montana injustice if reference were not made to the Milk River country, the great Indian reservation of 17,680,000 acres in the northern part of the State which has recently been open to settlement. This region has not been examined by the author, but from conversations with a number of its well-informed inhabitants it appear that the soil is very fertile, and that during average moist years excellent crops can be raised there without irrigation. This last statement, however, should not be too readily accepted. It is probable that some storage water may be retained in the hills along the British line, though its development will doubtless involve international questions.
A GLANCE AT THE FUTURE.