26 BULLETIN 852, IT. S. DEPARTMENT OF AGRICULTURE. 



2. Water entered the riser from an 8-inch pipe directly opposite 

 the pipe line tested. In the reach, 1,310.9 feet long between gauges 

 there are 3 smaller riser pipes. Gauge No. 2 is attached to a 

 piezometer identical in construction with No. 1, held in a position 3 

 feet above the outlet of the pipe. 



The water for this system is clear, being pumped from wells in the 

 "Palomares Cienaga." 1 So far as the writer was able to determine 

 from the inlets and outlets of pipes in this system, there was no 

 deposit of either vegetable or mineral nature. 



The nominal diameter of the pipe was used in computing the area 

 and quantity. As the velocity was found by the direct method, any 

 difference between the true and the nominal area does not affect the 

 velocity. If methods of construction used in the eighties were the 

 same as to-day, it is possible the pipe is undersized, as that appears 

 true of most present-day pipes. 



As it was not practicable materially to vary the discharge in the 

 pipe the three observations were taken at about the same velocity, 

 although extended over two days. The velocity for any one run 

 was taken as the mean of three batches of fluorescein, injected with a 

 "color gun" into the intake of the pipe line at the foot of the riser 

 pipe at gauge 1, and observed in the low riser pipe at gauge 2. Water 

 was immediately withdrawn from the pool so that there was no 

 uncertainty due to color lagging at the outlet. 



The capacity of this pipe is slightly greater than that of most 

 pipes built in the eighties, but it appears to be absolutely clean, 

 though with rough joints. The value of C s is about 0.292. 



No. 2, Experiment S-21. — 10-inch jointed cement pipe, Irrigation 

 Co. of Pomona, Calif. — This pipe line, between boxes 364 and 366, 

 was laid in 1888. The gauges and piezometer connections were 

 identical with those used and described under No. 1. Piezometer 

 No. 1 was placed 6 feet down the pipe line from the riser pipe forming 

 delivery box No. 364 while piezometer No. 2 was thrust 1.7 feet into 

 the pipe against the current, from box No. 366. A reach of line 

 1,107 feet long, straight in alignment and profile, was thus tested. 

 Three batches of fluorescein were timed for each observation, the 

 mean time being accepted in computing velocity of the water. The 

 nominal diameter was accepted in computing areas and quantity of 

 water (see No. 1, p. 25). So far as is known, this line had never 

 been disturbed since it was laid. There is probably little or no sedi- 

 ment in the line, as the water is clear. The capacity of this line is 

 slightly more than usual in this vicinity, the value of C s being about 

 0.272. 



No. 3, Experiment S-28. — 10-inch jointed cement pipe, San 

 Antonio Water Co., Ontario, Calif. — This experiment was conducted 

 on a straight reach of pipe laid in 1905 diagonally through an orange 

 grove. In the 10 years since then it has not been necessary to dig 

 up the pipe for root troubles. The nominal diameter was accepted 

 in computing area and quantity of water (see No. 1, p. 25). Both 

 gauges consisted of piezometer tubes of type A leading to water 

 columns in glass. The orifices for gauge 1 were located 12.8 feet 

 down the pipe from its intake in a masonry division box, while those 

 for gauge 2 were 936.2 feet farther downstream, and 2 feet above the 



i The Uso of Underground Water for Irrigation at Pomona, Calif., by C. E. Tait, O. E. S. Bui. 236, U. S. 

 D.A.,p.35. 



