USE AND WASTE OF IRRIGATION WATER 



By G. E. P. Smith 



What becomes of the irrigation water? The irrigator knows 

 that in a general way the water is beneficial, in fact, is necessary ; 

 he does not know just where the water goes after it sinks into the 

 ground, nor does he know just how much of the water applied to 

 the land actually does useful service and how much of it is wasted. 

 In the early days of irrigation in any country, the chief interest 

 and energy are exerted in developing the water. But when the 

 water supplies are so fully developed as they are in Arizona at the 

 present time, then farmers and others interested in agriculture must 

 study the efficiency of irrigation in order that Avaste of water may be 

 reduced and the water supplies may be made to serve as large an 

 acreage as possible. It must be confessed that in some communi- 

 ties the various losses of irrigation water aggregate as high as 80 

 percent of the total quantity of water diverted from the stream. If 

 the losses in such a community can be cut down to 60 percent, the 

 remaining useful portion is increased from 20 percent to 40 percent, 

 that is, it is increased two-fold. There are, indeed, inviting possi- 

 bilities of doubling the irrigated area in certain Arizona valleys 

 where already the entire water resources are thought to be fully 

 developed. 



A survey of the water supplies of the State at the present time 

 indicates a shortage in the supply for this year on many streams, 

 and the Roosevelt Reservoir contains less than one-half of its full 

 capacity. Reservoir supplies must be conserved as far as possible, 

 in the fear that the present dry year may be followed by another 

 equally dry. It is very pertinent, therefore, that this year the 

 farmers should make a special study of their methods of irrigation 

 in the effort to conserve the water supplies to the utmost. 



TRANSPIRATION 



Plants, like animals, breathe. The surfaces of leaves, and to a 

 less extent of stems, are covered with innumerable minute breath- 

 ing pores. Thru these small openings carbonic acid gas is taken 

 in from the atmosphere and moisture is given out. It is a vital 

 function of all plants to gather moisture thru their roots and to 

 expire the moisture thru the minute stomatal pores into the air. 



