50 BULLETIN 1026, U. S. DEPARTMENT OF AGRICULTURE. 



bells Draw. Diversions included a small amount delivered to the 

 Ripple ranch and a large head taken by the Scurvin Ditch. The 

 average discharge at the head was 172 second-feet and the loss was 

 20.6 second-feet. This is at the rate of 1.29 second-feet per mile or 

 0.75 per cent of the total flow. The section measured includes a 

 stretch of natural channel and for that reason the loss per square 

 foot of wetted area can not be determined with any degree of 

 accuracy. 



Two measurements were secured on the Larimer and Weld Canal 

 in 1917 while water was being carried for storage in the Windsor 

 Reservoir. The section measured included a stretch 12 miles long 

 with a 30-foot bottom between the head of the canal and Lake 

 Lee. The first observation included a period of 12 days between 

 March 29 and April 9 when the average discharge at the head of the 

 canal was 63 second-feet. The loss during the period was 0.92 second- 

 foot per mile or 1.5 per cent of the total flow which is equivalent to 

 a loss of 0.81 cubic foot per day per square foot of wetted area. The 

 second measurement included a period of 14 days between May 2 

 and 16 when the average discharge at the head Avas 242 second-feet. 

 During this period this loss was 1.33 second-feet per mile or 0.5 per 

 cent of the total flow which is equivalent to a loss of 0.64 cubic foot 

 per day per square foot of wetted area. 



When the investigation was undertaken it was believed that the 

 difference between the duty at the head of canals and the duty at 

 the head of representative laterals would give a fair approximation 

 of the average loss in main canals and that the difference between 

 the duty at the head of the lateral and at the farm would give the 

 approximate loss in the laterals. On this assumption, if the aver- 

 ages shown in Table 14 are applicable to the entire valley, there 

 was in main canals in 1916 a loss of 7 per cent and in 1917 a gain 

 of 7 per cent. However, the data shown in the table are too meager 

 to warrant the acceptance of these figures, but similar results are 

 obtained by comparing the duty at the farm with the duty at the 

 head of canals. In Tables 10 and 11 the total suppl}^ of water of 

 the canals listed is shown to have been 395,000 acre-feet in 1916 and 

 414,000 acre-feet in 1917. By applying to the acreage of the various 

 crops the figures representing duties, the majority of which are shown 

 in Tables 9 to 14 and 18 to 27 it is possible to determine the total 

 demand for each year under the canals listed. Duties for corn, 

 peas, and other crops occupying less than 10 per cent of the acreage 

 may be estimated without introducing a considerable error. The 

 demand for 1916 determined in this manner was 354,000 acre-feet 

 and to satisfy this demand there was a supply of 395,000 acre-feet, the 



