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Gross Duty of Water Under Sunnyside Canal, Washington. 



Year. Area irrigated (acres). Quantity of water per acre, 



(acre feet). 



1898 

 1899. 

 1900. 

 1901. 

 1902. 

 1904. 

 1909. 



6,883 

 8,497 

 10,947 

 14,964 

 18,870 

 32,000 

 47,000 



11.4 



10.6 



10.2 



9.6 



9.1 



6.0 



4.57 



This table shows that after 11 years only two-fifths as much water was 

 used as in the first year, or the same amount of water will irrigate 2^ 

 times as much land. 



The duty of water measured at the heads of laterals. On new canals the 

 average of measurements made on several canal systems shows that about 

 50 per cent, of the water diverted is delivered to the laterals. On older 

 canals the percentage is much higher. For the Sunnyside Canal in eastern 

 Washington it was 79 per cent, in 1909. 



The net duty of water is the duty as measured at the margin of the 

 fields. This duty is much higher than the gross duty as shown by the 

 table below. 



Quantities o Water Delivered to Several Farmn Compared With Water Received 

 at head of Main Canal, or Xet Duty vs. Gross Duty. 



These measurements show that for the Gage canal system, which con- 

 sists of a main canal, concrete lined with cement mortar about 1 inch thick, 

 and pipe distributaries, 92 per cent, of the water diverted reaches the land. 

 The measurements for the Sunnyside canal show the increase in efficiency 

 of a system as it gets older. The above results indicate that in a new canal 

 system of unlined earth canals the water delivered to the farms is probably 

 not more than 40 per cent, of the water diverted. For old canals in good 

 condition the efficiency will be increased to 65 or 70 per cent. 



2. Duty of Water for Orchards. 



There is relatively little data on the duty of water for deciduous orch- 

 ards. The data which is of most interest to British Columbia fruit growers 

 is that obtained for the orchards of Washington, Idaho and Montana. Mr. 

 S. O. Jayne, Irrigation Manager in the State of Washington for the U. S. 

 Department of Agriculture, gives the following information: 



"The water on a 20 acre apple orchard at Wenatchee was measured 

 during the season of 1908, showing that a depth of 23.04 inches was ap- 

 plied between May 13th and September 23rd. On the same orchard in 

 1910 27 inches of water were used, the first irrigation was May 30th and 

 the last September 12th. The trees were seven years old in 1908 and bore 



