30 
parties L0, 4, 3, 3, and 2 cubic feet of water per second from the Big 
Thompson No. 1 ditch, for the carrying of which they charge 50 per 
cent of the water carried. 
The cost of operation is for superintendence $1,500 and for repair;: 
about $350 per year. 
RESERVOIRS. 
The reservoir system of district No. 4, while not as complicated a^ 
that of district No. 3, a is as well developed and as efficient. No more 
water escapes from district No. 4: than from district No. 3, and prob- 
ably not as much. Its inlet ditches are comparatively short and the 
reservoirs lie at a good elevation, making it unnecessary in all but one 
case to discharge into the river and take water in exchange. 
Almost all the reservoir sites are found to be natural depressions. 
These depressions often form natural reservoirs and contain water 
drained into them from the surrounding lands; others have the rim 
depressed at one point, and through this break the water escapes. In 
improving the sites a dam is thrown across the lowest point in the rim 
and the capacity of the reservoir largely increased. The dams are 
generally of earth riprapped with stone, with outlet pipes running 
through them, controlled by valves. 
The soil in these reservoirs being the washings from the surrounding 
lands and of an adobe or clay character, is almost impervious, and forms 
an excellent bottom, through which very little water escapes. 
Very few reservoirs have been made by placing dams across water 
courses, as they are much more expensive, as well as more dangerous, 
the sudden floods often endangering the structures and necessitating 
the construction of proper wasteways and constant watching. In such 
reservoirs, also, considerable annoyance and expense is incurred on 
account of the necessity for allowing the natural flow to pass unimpeded 
through them when the water is needed for direct irrigation by the 
ditches below. 
Fortunately, there is an abundance of good natural sites in this dis- 
trict other than those found in the beds of the streams. Some excel- 
lent sites which exist in the mountains have not been utilized, as those 
in the immediate vicinity of the farms could be constructed more 
cheaply and more easily controlled. Storing water in the mountains 
necessitates the use of the river channel to convey it to the head of 
the ditch which carries it to the land irrigated. Here a division of the 
reservoir water and the natural flow of the stream must be made. 
"In U. S. Dept. Agr., Office of Experiment Station?, Bulletin No. 92, on "The 
Reservoir System of the Cache la Poudre Valley," by the late E. S. Nettleton, will 
be found an excellent description of the reservoirs and reservoir sites of district No. 3. 
What is there said is equally true of the reservoirs of district No. 4. The general 
physical characteristics and the method of management, construction, and distri- 
bution are the same. 
