62 



"In general the most water is applied in districts that require the least. 

 Wherever water is cheap and abundant the tendency seems to be to use 

 large quantities, regardless of the requirements of fruit trees. In Wyom- 

 ing the duty of water is seldom less than at the rate of a cubic foot per 

 second for 70 acres. In parts of southern California the same quantity of 

 water not infrequently serves 400 acres, yet the amount required by the 

 fruit trees of the latter locality is far in excess of the former. In recent 

 years the tendency all over the West is toward a more economical use of 

 water and even in localities where water for irrigation is still reasonably 

 low in price, it is rare that more than 2 % acre feet per acre is applied in a 

 season. This is the duty provided for in the contracts of the Bitter Root 

 Valley Irrigation Company of Montana, which has 40,000 acres of fruit 

 lands under ditch. Since, however, the water user is not entitled to receive 

 more than one-half of an acre foot per acre in any one calendar month, it 

 is only when the growing season is long and dry that he requires the full 

 amount." 



"In the vicinity of Boulder, Colorado, the continuous flow of a cubic foot 

 per second for 105 days serves about 112 acres of all kinds of crops. This 

 amount of water if none were lost would cover each acre to a depth of 

 1.9 feet." 



3. Duty of Water for Alfalfa. 



A number of measurements have been made to determine the quantity 

 of water applied on alfalfa fields. In Washington measurements on tue 

 Sunnyside project of the Yakima valley gave a net duty in 1909 of 2.79 

 acre feet per acre. This represents the average for 47,000 acres included 

 in the system, of which about 30,000 acres were in timothy, clover and 

 alfalfa, 10,000 acres in orchard, and the remainder in potatoes. Professor 

 Waller of Pullman, Washington, obtained from measurements made in 

 1905 on five farms in Washington, aggregating 189 acres, an average net 

 duty of 2.35 acre feet per acre or a total depth of 28.2 inches, the values 

 for the different farms ranging from 21 inches as a minimum to 39.0 

 inches as a maximum. The average yield was 7.85 tons per aero; the 

 field receiving 39 inches of water gave a yield of 8 tons per acre, and that 

 receiving 21 inches 7% tons per acre. 



In Idaho, measurements made by D. H. Bark in 1910 on five farms in 

 the Big and Little Wood valleys gave the following results: 



Net Duty of Water for Alfalfa on lliu and Little Wood River Valley*, Idaho. 



The large depths of water applied on the farms of Ketchum and Hailey 

 are due to the amount of water decreed by court being far in excess of the 

 needs 01 the land; this leads to wasteful and careless use. These amounts 

 are double or triple the amount used upon similar and more porous soils in 

 the upper Snake River valley. The soil absorbed a large quantity of water 

 but retained only a small part of it, the remainder being lost by percolation. 



4. Duty of AVater for Potatoes. 



Measurements were made in 1905 on four tracts of potatoes in Wash- 

 ington aggregating 27 acres. A mean depth of 17.6 inches of water was 

 used and the yield was 8.5 tons per acre. Other scattered measurements 



