THE FLOW OF WATER IE" CONCRETE PIPE. 31 



No. 14, Experiment S-58. — 18-inch jointed cementpipe, Edwards 

 private line, in Oakdale irrigation district, Calif. — Water for irri- 

 gation is conveyed across a depression from a main lateral of the 

 Oakdale district to a knoll, in a plain cement-pipe inverted siphon 

 1,283.6 feet long, subject to a maximum head of about 11 feet. 

 The pipe was made on the ground by the owner of the farm, aided 

 by a man with a small amount of practical knowledge of pipe mak- 

 ing. There is one 12-inch standpipe and one 12-inch valve near the 

 low point. As both inlet and outlet of this line were submerged 

 and it was not possible to vary the discharge to secure much 

 variation in the velocity, practically all of the line was used in 

 the experiments. Water columns attached to piezometer tubes of 

 type A were used at both ends of the reach. Piezometer No. 1 was 

 set 5.1 feet down the pipe from the intake chamber and No. 2 

 was thrust upstream from the outlet chamber a distance of 7 feet. 

 Velocities were, determined by the use of a saturate solution of po- 

 tassium permanganate, injected at the inlet and observed at the out- 

 let of the siphon. The nominal size of the pipe was accepted, as 

 it was not feasible to secure measurements of the pipe itself. 



From the fact that the value of C s is very low, about 0.254, the 

 writer would judge that sediment has obstructed this pipe more or 

 less. 



No. 15, Experiment $-56.— 18-inch jointed cement pipe, Batdorf 

 line, Oakdale irrigation district, Calif. — Irrigation water is conveyed 

 from one open-channel lateral to another down a gentle hillside and 

 across about 600 feet of level field by means of an 18-inch cement 

 pipe made of jointed units each 2 feet long. There are four vertical 

 standpipes rising above the hydraulic gradient on the total length 

 of about 2,500 feet. Examination of the pipe at these standpipes 

 showed that the line was full of water only through about the last 700 

 feet. A reach was chosen from a standpipe to the outlet, a length of 

 582.3 feet. A tube of type A was dropped down the standpipe and 

 carried by the current 2 feet down the pipe. A similar tube was 

 thrust 21 feet up the pipe from the outlet. Gauge No. 1 was a 

 water column in a glass tube, while piezometer tube No. 2 was con- 

 nected with a stilling box and the surface of the water determined 

 by a hook gauge. The velocity was determined with a solution of 

 potassium permanganate, timed from the standpipe to the outlet. 

 As it would have been a difficult matter to determine the moment 

 of injection down a standpipe 10 or 15 feet high above the pipe 

 line,- the solution was placed in a corked bottle held in a sack made 

 from a piece of fly screen which was wired to the end of a long one- 

 eighth-inch iron pipe. The bottle was thrust down the standpipe 

 and smashed against the bottom of the pipe line, thus releasing the 

 color but retaining the glass within the screen. The line under the 

 standpipe was clean of deposit, as nearly as could be determined by 

 feeling with the iron pipe rod, and from the appearance of the outlet. 

 The value of the friction factor would indicate this to be true. The 

 pipe is straight, buried about 3 feet, appeared from inspection of 

 the outlet to have good joints, and was probably in good condition. 

 The value of C s is 0.284. 



No. 16, Experiment S-42. — 20-inch jointed concrete pipe, lateral 

 C, British Columbia Fruitlands Co., Kamloops, British Columbia, 

 Canada. — The main canal on this project is concrete lined, skirting 



