Arizona Agricultural Experiment Station 



487 



table XXI. — Experiment station pumping plants 



wells are of the- same type, 3'et each is best adapted to the local 

 conditions. 



The Mesa and Yuma plants are new. For the Mesa plant a 

 rotary pump was selected, because of the shallow water table, the 

 moderate yield and the necessity for pumping extensively on two 

 different lifts. The pump is set just above the water level and is 

 self-priming. The engine is depressed in a pit, which will become 

 the basement of a small building later on. This arrangement ob- 

 viates the necessity for a long belt. For the Yuma plant a recipro- 

 cating pump was chosen on account of the small discharge. The, 

 driven well being too small to admit a i)ump cylinder, a pit was, 

 dug to the water table, the well pipe was cut off and threaded, and 

 the cylinder was attached directly to the pipe. This scheme assures 

 the greatest possible draw-down and, therefore, yield. 



The engines are nearly all oil engines (that is, they burn tops, 

 a low-grade distillate), with the exception of the irrigation labt)ra- 



