37 
Frictional Resistance in Artificial Waterways 
£ZU 
force of current to remove large obstructions of a floating nature. 
Neither end of the pipes were flared, and at the time of these 
tests while the outlet ends were entirely submerged the water at the 
intake ends was only about three feet deep. The cross-section of 
the pipe was completely filled at about four feet from the entrance. 
A deposit of silt about 0.5 feet thick covered the bottom of the pipe 
at the outlet. The water at inlet and outlet was very quiet. 
SIPHON UNDER PURGATOIRE RIVER, LAS ANI¬ 
MAS. The Jones Extension of the Las Animas Consolidated 
Canal conveys water across the Purgatoire River by means of a 
36-inch wood stave pipe. The pipe is buried about ten feet be¬ 
neath the shifting sands of the river bed, and has a maximum pres¬ 
sure head, at its lowest point, of about 20 feet. No- provision is 
made for draining the siphon at its lowest point. This conduit 
was tested for less of head on August 8, 1913. It was newly con¬ 
structed, having been in operation only a portion of that season. 
Conditions were especially favorable for this experiment as the 
water entered and left the channel very quietly, and it is thought 
the 2.16 feet velocity obtained therein, together with the short 
period it had been in use, is reasonable evidence that no debris or 
silty deposits existed in the bore. 
GENERAL RESULTS. Table 9 gives the data relative to 
the dimensions of pipe and maximum -pressure heads, together 
with the hydraulic elements arranged in the order of correspond¬ 
ing mean velocities in the bore. In columns 9, 10 and 11 are 
given values of the coefficients commonly used in estimating the 
carrying capacity of pipe lines. Column 8 enables a comparison 
to be made of the loss of heads in the siphons on a basis of a 
i,ooo-foot length of pipe. The other columns are self-explanatory. 
The wide range in the amount of lost head per 1,000 feet of 
pipe, and the values of the coefficients hardly justify a close com¬ 
parison. 
As was previously stated, the high values of (11) obtained for 
some of the siphons indicates a deposit of debris at the low point 
of the siphon, or -other condition which retards the flow of water. 
There were no means for inspecting the interior of the pipe, but as 
