IRRIGATION IN MONTANA 



Irrigation antedates the discovery of gold in Montana. Father De Smet, in 1845, 

 in the Bitter Root valley, was its first exponent, and a small irrigated settlement grew 

 lip around St. Mary's mission. The expansion of irrigation, between 1860 and 1870, 

 was simultaneous with that of agriculture, some of the men disappointed in gold mining 

 turning to farming in the rich grass-covered valleys. 



At first only crude ditches carried part of the direct flow of a few of the mountain 

 streams to the land. It was natural that in the following years the lands which could 

 be most easily and cheaply watered were taken up and irrigated first, leaving for later 

 years the development of projects which required more expensive ditch construction, 

 diversion and storage dams, and pumping plants. 



Now Montana has nearly 3,000,000 acres of irrigated land, and, according to the 

 U. S. Census figures for 1920, its irrigation works served 10.5 per cent of all irrigated 

 lands in the country. In irrigated lands Montana ranked fourth, being exceeded only 

 by California, Colorado and Idaho. The same source of information shows that the 

 estimated final cost per acre of all existing enterprises was $16.19, which is a lower 

 average with a single exception, than for any other western state. About 90 per cent 

 of the lands irrigated in 1919 in the state were watered under gravity systems from 

 streams. 



The Montana Irrigation Commission on a survey made in 1920, reported 2,136,974 

 acres actually irrigated, with an additional 885,543 acres to be watered soon under plans 

 or works completed at that time. It estimated 2,266,000 acres more were feasible of 

 irrigation. 



The Montana Experiment Station in Bulletin 103, says of the water supply: 

 "Montana is much better supplied with streams than many of the western states, as 

 there is no part of it which can be classed as desert, all portions yielding at least 

 some run-off. The greater portion of the discharge of the main streams comes from 

 the higher portions of the state along the Rocky Mountains and their spur ranges. * * * 

 Because of the narrowness of the valleys and the height of the bordering slopes, the 

 diversions practical from the lower portions of the main streams are limited to less 

 than the available supply, and the Yellowstone, Missouri, and Clark Fork of the Colum- 

 bia will always carry from the state water which would be of great value if its use for 

 irrigation were feasible. 



"The amount will be continually reduced, however, by the extension of irrigated 

 areas on headwater streams and tributaries. On these the direct flow during the low 

 water period has been largely appropriated." 



The irrigated area is being steadily enlarged by new projects, and by the extension 

 and improvement of many older ones. Several comparatively small projects are under 

 construction, many more contemplated, and preliminary arrangements and surveys have 

 been made for the construction of several larger projects covering many thousands of 

 acres. The enormous water power resources and developments within the state have 

 a direct bearing upon irrigation, in that the cheap power admits of pumping water at 

 moderate costs to irrigate relatively high lands. This form of irrigation is already in 

 successful operation upon a number of projects and its further utilization is contemplated 

 in various sections of the state. Besides these, many farmers in the non-irrigated areas 

 are constructing earthern dams across coulees to hold the spring run-off for irrigating 

 part of their land, and the growth of this practice promises to add materially to the 

 part-season irrigated area. 



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