86 BULLETIN" 852, U. S. DEPARTMENT OF AGRICULTURE. 



each side of manholes and using hook gauge from top of straightedge down to surface 

 of water. 



The nominal slope of the pipe was taken in the computations of the 

 retardation factors for the various formulas. As shown in Table 11, 

 page 68, this experiment indicates a value of n in the Kutter formula 

 of 0.0142, and so far as can be determined from the descriptions of this 

 pipe and the 22-inch pipe the values are accounted for by the manner 

 of making the joints. (See discussion No. 50 above.) 



No. 53, Experiment FF-3. — 36-inch jointed cement pipe of 

 Southern California Edison Co., Lytle power plant, California. — The 

 description of the experiments upon this line, as taken from corre- 

 spondence with Mr. Finkle, reads : 



This 36-inch line, laid in 1904, was given a slope of 5.28 feet per mile, and allowance 

 made for acceleration of the water at the intake (as explained for pipes Nos. 50 and 

 51, which see also for manufacture of pipes). The pipe showed a delivery of water 

 amounting to 20.06 second-feet, When running within 1J inches of the top, or with a 

 depth of water equal to 34£ inches in the pipe. 



In the year 1908 a second test showed the capacity had increased, so as to deliver 

 21.2 second-feet under the same conditions as it previously delivered 20.06 second-feet. 

 Investigation showed that this was due to a fine deposit of carbonate of lime formed 

 on the interior of the pipe, almost making a glazed surface over the cement. This 

 was deposited by the water of Lytle Creek, which contains considerable lime carried 

 in the water in the form of bicarbonate. 



This line contains numerous curves between tangents of various lengths, but none 

 of the curves has a radius less than 34 feet. 



The discharge was determined by passing water over a rectangular, fully contracted 

 Francis-type weir in three-sixteenths-inch steel plate, and depth was observed with 

 a hook gauge. The immediate intake was tapered from 44 to 36 inches in diameter 

 (see PL X, fig. 2). The depths of water in the pipe, from which the velocity and hy- 

 draulic radius are computed, were measured by holding a straightedge against the 

 upper invert on each side of the manholes and measuring from the top of straight- 

 edge in manholes to the surface of the water. 



The nominal slope of the pipe was taken in computing the retarda- 

 tion factors for the various formulas. According to the experiments, 

 the glazing action of the lime improved the value of n from 

 0.0145 when the pipe was new to 0.0138 when it was 4 years old. 

 Experiments at the end of, say, 10 years might show a very efficient 

 surface but a decrease in capacity, due to throttling of the water 

 section, assuming the deposition oi lime to continue. 



No. 54, Experiment Ehle-1 — Victoria Aqueduct, Vancouver Island, 

 British Columbia, Canada. — Water was first turned into this pipe line 

 on May 14, 1915 (see Nos. 30 and 31). On May 23 and 24, 1915, 

 Boyd Ehle conducted a series of tests to determine the friction factor 

 n in the Kutter formula. 1 As shown in Table 11, p. 68, the 

 range of these tests extended from 3.36 second-feet flowing with a 

 depth of but 8f inches up to 40.59 second-feet which filled the pipe, 

 thus extending through the transition from an open channel (i. e., 

 with water surface exposed to the air) to a pipe running full of 

 water. It is not often that an installation is such that the behavior 

 of water may be studied through this transition, as a pressure pipe 

 is full of water, whatever the discharge, and a flow-line pipe as a rule 

 is protected against complete filling by spillways near the upper end 

 of the line. 



The reach covered by this series was 800 feet long. The upper 

 end is near the pipe-line intake at Sooke Lake. The discharge was 

 measured over an 8.02-foot sharp-crested rectangular weir, corrected 



i Engin. Rec, Oct. 2, 1915, vol. 72, p. 409. 



