SECTION OF IRRIGATION AND METEOROLOGY. 31 
miles per hour, as deduced from Professor Russel’s observations ; ]: 
2 per cent, from Colorado observations of 1889, by L. G. Carpenter.* 
§ 45 . SUMMARY AND CONCLUSIONS. 
1. The losses from reservoirs are from seepage and evaporation. 
2. The seepage losses are dependent on the condition of the 
reservoir site, therefore different for different sites. 
3. The seepage losses were determined on a series of reservoirs 
near Fort Collins, in the winter of 1895-6 and 1896-7. 
4. The seepage losses may be great. In the lakes under 
measurement, the losses in some cases were less than from evapora- 
tion alone. 
5. In some cases, lakes may gain from seepage from irrigated 
lands, and the gain may be more than the combined loss from seep- 
age and evaporation. 
6. In the cases where loss from seepage occurred, the loss was 
at the rate of about 2 feet in depth over the area of the lake, per year. 
7. This amount does not necessarily apply to other sites, and 
other observations are needed before general statements respecting 
loss from this source can be made. 
8. The seepage decreases after the lake is first filled, from the 
effect of silting, and from having filled the porous ground underneath 
and connected with the site. 
9. Even in sand, there is a limit to the amount of seepage, and 
the time during which the loss is large. 
10. After sand beds connected with the reservoir are saturated, 
the losses from seepage will decrease. 
10 a. The loss increases with the depth, probably nearly as 
the square. 
11. The losses may be lessened, though not entirely prevented, 
by silting. 
12. The silting process is more efficient with small reservoirs, 
because of the better distribution of the silt. 
13. If the loss from seepage is not more than 2 feet per annum, 
the sites may be considered as practically water tight. In the case 
of canals, the losses often average more than that in twenty-four hours. 
EVAPORATION. 
14. The losses from evaporation, in the cases examined, are 
greater than those from seepage. 
15. The evaporation is not necessarily the same from adjacent 
bodies of water. 
t Trans. Am. Soc. C. E., 1883. J U. 8. Weather Bureau. * Report Exp. Sta., 1889. 
