156 THE IRRI0 11 ON A GE. 



although constantly flowing water, at a proper elevation for distribu- 

 tion by gravity, would seem to be an ideal source of supply, it is not 

 an unmixed blessing unless properly controlled. Proper control, by 

 . impounding in a reservoir or by capping the well so that its flow can 

 be stopped when there is no immediate use for the water, is essential. 

 In great enterprises the flow can be constantly used and the wells can 

 gush unceasingly, but on the farm flowing water in excess of needs is 

 apt to destroy much land. Again, a small flowing well, such as can be 

 cheaply secured in some places, is apt to cease to flow in a time of pro- 

 tracted drouth, just when its flow is most desirable. 



The behavior of this class of shallow flowing wells is shown by 

 recent experience in parts of California in which there have been three 

 successive years of deficient rainfall. There are belts where there 

 has always been until this drouth a flow from small artesian wells, 

 which are chiefly used for domestic and stock purposes; and, as the 

 ground water was near the surface, the crops and trees were trusted 

 to do their own pumping if they needed more moisture than rainfall 

 afforded. During this drouth these wells ceased to flow, and the ground 

 water sank too low for the shallow root system of the trees, and out 

 of reach also of the roots of field crops. Alfalfa fields died out, not 

 because the water was out of reach of alfalfa plants trained to seek 

 their own supplies, but because the usually high ground water dis- 

 couraged deep rooting, and the sinking of this water left the plants 

 high and dry and dead. Hundreds of acres of rich land were bare and 

 desolate, although the water stood but 7 to 10 feet below the surface. 

 This seems almost incredible in view of what has been recently learned 

 of cheap pumping. It was the freely expressed local opinion that 

 these flowing wells had proved a curse. If the water had never flowed 

 their owners would long ago have had recourse to pumping. If it had 

 never flowed, there would not have been the increase of alkali due to 

 surface flooding from such weels, with not volume enough to carry the 

 alkali away below. 



But while this is true, there are also flowing wells of great output 

 and of enduring flow, which are rendering thousands of acres of arid 

 land productive. Such full information on the subject of artesian 

 wells, both those which flow and those which require pumping, is so 

 easily available in the publications of the Department of Agriculture 1 

 that further discussion is not necessary here. 



PUMPING FOR IRRIGATION. 



Undoubtedly the most interesting and important phase of recent 

 progress in irrigation practice is found in the use of the pump as a 



Notably in the Reports to Congress on the Artesian and Underflow Investiga- 

 ions, 1892. 



