57 



BUTY OF WATER IN MONTANA. 



Montiina is a laroo State, bat the bulk of it.s aoriiailtural products 

 will always be raised on comparativcl}' small areas, because of the 

 limited water supplw This being true, the duty that can be secured 

 for its water supply will measure to a large degree the future possi- 

 bilities in agriculture. For this reason the study of the duty of water 

 and the conditions which influence it assume great importance. 



If it is desired to reclaim an arid tract of land the engineer must 

 decide not only upon the total quantit}' required for the season but 

 also the maximum amount to be delivered at any one time. Having 

 decided as to the largest volume of water required for any given 

 period, he designs the canal structures accordingly. If this estimate 

 is too large, a part of the money of the investor will serve no useful 

 purpose. On the other hand, if the estimate is too small, the enter- 

 prise will be a partial failure, for there will not be sufficient water to 

 irrigate all the land. Similarly, when water is to be stored to irrigate 

 land, the capacity of the storage reservoir and the cost of the structure 

 are both dependent to a large extent on the service which the stored 

 water will perform when applied to the soil. There is the same 

 necessity for accurate information on this point when a pumping 

 plant is to be installed. Otherwise money will be wasted in the purchase 

 of a plant of too large capacit}' or else the plant first installed will be 

 too small to raise the requisite amount of water and will have to ))e 

 replaced by one of greater capacity. 



Thus it is evident that from an engineering standpoint a knowledge 

 of the amount of water required for land of a known character and 

 for particular crops is necessary. Such knowledge is all the more 

 important when one considers that about 80 per cent of the irrigable 

 lands of Montana is yet to be reclaimed. Judging from the progress 

 made during the past tifteen years, the extent of land reclaimed in the 

 next fifteen years by private enterprise will amount to 1,750,000 acres. 

 If this area is increased b}^ a third of a million acres of Government 

 land, which it is presumed will be reclaimed by the Federal Govern- 

 ment luider the operation of the irrigation act passed June 17, 1902, 

 it will increase the amount to over 2,000,000 acres. There is perhaps 

 no question of more vital importance to the future of Montana than 

 a knowledge of the right amount of water to apply, not only to the 

 land which may be irrigated in the next fifteen years, but to all the 

 irrigable lands. 



When one considers the broader features of this subject, which per- 

 tain to the equitable allotment and distribution of water, its impor- 

 tance is much increased. The basis of all equitable allotments must 

 rest on the amount of water required to properly irrigate land. This 

 question thus becomes one of the main factors in the determination of 



