344 IRRIGATION PRACTICE 



headgate of the canal and the laterals, and undoubtedly 

 much of the remaining 40 per cent is lost between the 

 heads of the laterals and the farms. Observations were 

 also made by the government investigators on the quan- 

 tities of water actually applied to crops, with average 

 results as follows: Alfalfa, 32 inches; wheat, 18 inches; 

 barley, 16 inches; potatoes, 28 inches; sugar beets, 25 

 inches, with an average for these crops of about 23 acre- 

 inches. For an irrigation season of about ninety days, 

 this would mean a net duty of 100 acres. This is much 

 larger than the gross duty as above given. The losses 

 from the canals are always large, averaging 5.77 per cent 

 per mile; and Fortier declares that perhaps less than one- 

 third of the water diverted by the canals is actually used 

 by the crops. 



206. Bear River Canal experience. One of the most 

 notable canals in western America is the Bear River 

 Canal, which began its actual operations in 1891. Its 

 first duty of water was 40 acres for six months for each 

 second-foot of water, or a depth of 4.2 feet during the 

 six months. In 1903, after twelve years of experience, it 

 was obvious that too much water was being used. The 

 ground water table was rising rapidly near the surface, 

 alkali was becoming visible in certain low sections, and, 

 all in all, the evils from over-irrigation were observed. 

 Careful measurements were then made of the water 

 delivered, and attempts were made to increase the duty 

 of water. For four years thereafter, 6,000 measurements 

 were made at the head of the canal, at the heads of the 

 laterals, and at the gates to the individual farms. Accord- 

 ing to Wheelon, it was found in 1903 that a duty of 67 

 acres per second-foot prevailed. In 1904, this had been 

 raised to 120 acres, and in 1905 to 138 acres. These 



