27 



' DITY OF WATKK I NDKK WKST (iAM^ATIN KIVER. 



Tlie iriij^utioii season in the (iallatiii Valley oxtonds from about the 

 iiiicldle or last of May until about Aui^ust l."). Tliore are, of course, 

 localities w here irrigation of some crops is be^un before the middle 

 of May, and wiiere the season lasts beyond the middle of August. In 

 such cases, however, the crop raised is usually not one of the regular 

 crops ot" the valley, for these silmost without exception receive the 

 irriuation they reipiire in the j)eriod mentioned. In many cases, 

 although wattn* is tununl into the canals anywhei'e from the 1st to the 

 15th of May, extensive irrit>;ation does not beuiii until in the forepart 

 of June, de[)endint>- almost entirely of course on the nature of the sea- 

 son, whether (\irlv or late. 



Fig. 4. — Discharge of West Gallatin River, 1902, and diversions therefrom. 



The first crops to receive water in the spring are pastures and 

 meadows, clover and alfalfa, after which the grain is watered. As 

 grain is the main crop of the valley, irrigation occupies a large part 

 of the season. After the grain is sufficiently watered and the first hay 

 crop is cut, the water is again applied to the clover and alfalfa land 

 for the .second ha}" crop. 



In the majorit}' of cases alfalfa and clover receive but one watering 

 for each crop, grain receiving from one to three waterings, according 

 to the locality. The numl)er of waterings depends of course largel}^ 

 on the rainfall both as to its amount and as to the time it is received. 

 During the season of 1903 the rainfall came in sufficient amount and 

 at such time as to make but one irrigation necessary for each crop of 

 clover. . Grain was w^ell along also l)efore irrigation became necessar3\ 



During the spring of 1902 a series of investigations of the duty of 



