SPRAY IRRIGATION. 



11 



can run tests up to a flow of 20 gallons per minute. Larger and 

 deeper wells require special power equipment for testing. 



The boring of deep wells for artesian waters should be undertaken 

 by an expert familiar with the local underground conditions. De- 



termining in advance the probability 

 of obtaining artesian water sufficient 

 for irrigation purposes is a very diffi- 

 cult problem. Geologists. familiar with 

 the underground formations and hav- 

 ing records of some deep wells in the 

 vicinity upon which to base their judg- 

 ment often can render a fair opinion. 

 However, it always is more or less a 

 gamble until the well is completed, and 

 a farmer should not take the risk 

 unless he is prepared to lose. 



Deep wells are no more difficult to 

 pump than shallow unless the water 

 fails to rise to within suction lift of 

 the surface. When it is necessary to 

 sink a pit or a large casing deep into 

 the earth to admit the installation of 

 deep-well machinery, as is illustrated 

 in figure 6, the cost is apt to be great 

 and will be justified only where water 

 can be obtained in sufficient amounts 

 to irrigate a correspondingly large 

 acreage. 



Unlike water for drinking purposes, 

 water for irrigation need not be pure 

 from a bacterial standpoint. It is 

 therefore allowable to draw on both 

 waters near the surface and artesian supplies in the same well (fig. 6) 

 by having the casing perforated or slotted wherever a good water- 



' .'0. ,».-< 1 ,' 



Fig. 5. — Typical installation of 

 vertical-shaft centrifugal pump 

 in pit with half-turn belt. 

 Pump in this case is sub- 

 merged in water. 1, Engine ; 

 2, engine foundation ; 3, fuel 

 tank ; 4, belt ; 5, vertical 

 shaft and bearings ; 6, water- 

 cooling pipe for engine ; 7, dis- 

 charge pipe ; 8, pump ; 9, suc- 

 tion pipe ; 10, well casing ; 

 11, well screen. 



