THE PLOW OF WATER IN CONCRETE PIPE. 35 



a round pipe flow line. The siphon pipe is made of precast units, 

 each 3 feet in length. The pipe is practically straight in both hori- 

 zontal and vertical planes, the maximum head being about 8 feet. 

 This line was constructed in 1911, being thus in its fifth year of 

 operation at the time of the experiment. It carries water through- 

 out the year. A reach was chosen for test between a point 79 feet 

 from the intake chamber and a point 69 feet upstream from the 

 outlet manhole. Water columns attached to piezometers of type 

 A were used at both ends of the reach. Velocities were determined 

 by the use of solutions of potassium permanganate, injected at gauge 

 No. 1 and observed at the manhole beyond gauge No. 2. Measure- 

 ments of the initial pipe section at the intake chamber showed the 

 diameter to be 2.49 feet,, or 0.01 foot less than the nominal diameter. 

 No. 23, Experiment S-34.— 30-inch Jointed Reinforced Concrete 

 Pipe, "T) 1 Line", Umatilla project, United States Reclamation Service, 

 Oregon. — Water for irrigation is conveyed across the depression near 

 Hermiston, Oregon, in a 30-inch pipe laid in sections, each 4 feet long. 1 

 This line was constructed in the winter of 1909-10 and tested for 

 friction losses in 1911 by Mr. H. D. Newell. 2 The writer conducted 

 tests on the same reach of pipe during the season of 1915. See No. 

 12a (page 77) and No. 24a, for pipe description. Thus while com- 

 paratively new when first tested it had been in use nearly six seasons 

 when these experiments were made. The pipe units were each 4 feet 

 in length, cast in wood forms that had been coated with No. 26 sheet 

 steel. The mixture and wash coating is described under pipe No. 32, 

 page 41 . Gage No. 1 was a piezometer tube of type B inserted into the 

 water section of the pipe through a stuffing box, located above the 

 valve A in figure 3, Plate 2. Newell appears to have used the pressure 

 directly from a f-inch valve set in the pipe line. The writer found so 

 much air in the water column taken directly from this tap that he 

 judged a piezometer tube, even of type B, would give more nearly the 

 true pressure head (see discussion on page 15). This tube was con- 

 nected with a mercury manometer. At the outlet a piezometer tube 

 of type A was thrust 3.6 feet into the pipe, against the current. This 

 tube was connected with a stilling box and the water surface in the 

 latter was read by a hook gauge. The relation of the points plotted 

 on Plate VI for the Newell tests (No. 24) and for those made by the 

 writer (No. 23) indicate that the capacity of this pipe has diminished 

 slightly. This was to be expected, for Newell speaks of deposits in 

 the pipe after but one season while the writer's tests were made in 

 the sixth season. Until July of each year the water for this pipe 

 comes directly from the Umatilla River, through about 4 miles of 

 open canal, the last reach of which discharges in a direct line into 

 the pipe intake. This river water, taken during the high-water 

 period, would undoubtedly contribute greatly toward silt and debris 

 within the pipe as the maximum demand so far has not required a 

 velocity in the siphon in excess of about 2.5 feet per second. Veloci- 

 ties were determined directly with solutions of fluorescein, the mean 

 time of several batches being accepted in computing the mean velocity. 

 This pipe is quite straight in horizontal alignment, while the vertical 

 curves are long and gentle. There are five 6-inch valves and three 

 manholes on the reach tested. Examination of the outlet indicates 

 that the pipe is smooth and slimy inside. The color was injected into 



.- Eng. News, Feb. 16, 1911, Vol. 65, p. 208. " Id. May 1, 1913, Vol. 59, p. 904. 



