486 TVVKNTY-EIGHTH ANNUAL REPORT 



MACHINE-MADE CEMENT PIPE 



On account of the great importance of water economy in Ari- 

 zona this Station has taken a lively interest in the manufacture of 

 cement pipe and its use for irrigation pipe lines. In 1907 the Sta- 

 tion published a bulletin on the subject and has constantly advo- 

 cated the use of cement pipe for irrigating streams of moderate 

 size requiring pipe up to 24 or possibly 30 inches in diameter. For 

 farms that are under pump irrigation, pipe sizes from 8 to 20 inches 

 in diameter are required commonly. 



During the last few years pipe machines have been developed 

 for making cement drain tile in the Middle West, and during the 

 past year these machines have been modified so as to make irriga- 

 tion pipe. The opportunity presented itself to this department to 

 bring one of these machines to Pima County and to study machine- 

 made pipe and pipe-making. The results of these studies have 

 been prepared as a bulletin and will be published in the near future. 



The general conclusions of the study are that pipe-making by 

 machinery is entirely practical, that the pipe is much superior in 

 quality to hand-made cement pipe and that the cost is less. The 

 field for a new industry is open and inviting and pipe factories 

 should be built and equipped at a half dozen places in central and 

 southern Arizona. The ultimate result will be greater water econ- 

 omy, and an extension of the irrigated area. 



For the larger laterals and main canals cement lining is the 

 best method of improvement. Careful estimates show that by lin- 

 ing the canals of the Salt River Valley enough water will be saved 

 to permit an increase of 25 percent in the project area. 



EXPERIMENT STATION PUMPING PLANTS 



During the expansion of the Experiment Station work it has 

 been necessary to develop many pumping plants, both for outlying 

 stations and for the campus and the University Farm. A summary 

 <:i these plants with general comparative data is of interest and is 

 shown in Table XXI. 



In a semi-arid region such as Arizona water supplies are of 

 primary importance. The Yuma and Prescott plants are for do- 

 mestic supply only, but the others are designed for both domestic 

 supply and irrigation. The conditions are very variable, however, 

 and the fact that the design of pumping plants requires specialized 

 training is well illustrated l)y the list. It is to be noted that no two 



