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 TTeld 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 was 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 supply 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 
