246 UNIVERSITY OF COLORADO STUDIES 



section within one foot of the top is choked with a dense growth of an 

 aquatic plant, milfoil. The unfavorable conditions affect the flow to 

 such an extent that while the mean velocity is only 1 . 58 feet per second, 

 the surface velocity is 3 . 7 feet per second. See Figs. 10 and 10a. 



Observation No. 11. Farmers' Ditch in Loveland 



This ditch is in fair condition as to cross-section, alignment and 

 material, but it is about half filled with milfoil. The gradient is enough 

 to produce a high velocity, but the aquatic growth keeps the mean 

 velocity low. See Figs, n and 11a. 



Observation No. 12. Beasley Ditch at Boulder 



The channel here is wide and shallow. It is through gravel and fine 

 sand with a good many small cobblestones on the bottom. The banks 

 are held in place by logs laid parallel to the stream. Fig. 12 shows the 

 bed where there was but very little water in it. Fig. 12a is a cross- 

 section of the channel. 



Observation No. 13. Beasley Ditch near Water St. 



The bed of the ditch at this point is composed of gravel on the bottom 

 with cobblestones at the sides. The channel is unobstructed by vegeta- 

 tion. The alignment is on a slight curve. The general condition of the 

 ditch at this point would be classed as good. See Figs. 13 and 13a. 



Observation No. 14. Interstate Canal 1 



This canal is designed to carry 1,421 second feet at a velocity of 2.9 

 feet per second and with a depth of ten feet. The friction factor used 

 is 0.025. However, owing to the high velocity attained which endan- 

 gered the channel, the maximum flow allowed is 830 second feet. 

 The corresponding friction factor is 0.012. 



The following conclusions seem evident from the data at hand: 

 1. These experiments as well as those of Professor Fortier seem to 

 show that ^=0.025 is too high a value for design, especially for large 

 canals. This is exemplified in Observation No. 14. 



1 Reported by H. E Sovereign. 



