50 
SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
go down in the cellars, falling about six inches in three weeks, and 
eighteen inches in a little over two months. A measurement of the 
amount of water in the ditch was made October 16, at the time of 
gaging the river, both above and below the point where the great 
loss was suspected. The quantity in the canal decreased from 25.86 
cubic feet per second above the place, to 20.80 a little distance 
below, or a loss of 5.06 cubic feet per second. The total distance 
between the two measurements was forty-six rods. The total area 
of water surface was not noted, but with the increased breadth of 
the canal at the ravine crossing it is about one-half an acre. This 
would be equivalent to a depth of twenty feet, over the area wetted 
by the canal, in twenty-four hours. 
SOURCE OF THE INCREASE. 
§ 44. Whether the water forming this increase to the streams 
comes from the rainfall or from the waters applied in irrigation, is 
important to determine if possible. From the nature of the case, 
it is not possible to indentifv the water, but a comparison of the 
increase between different regions of greater or less irrigation gives 
some basis for a conclusion. If the increase is partially or wholly 
from irrigation, it follows that the inflow will increase from year to 
year, as the amount of irrigation increases ; that the lower reaches of 
streams will have a more regular supply; that the increase will 
show itself farther down stream, making it possible to gradually 
bring more land under cultivation; that many of the dry streams 
will become living ones; and that the damage which riparian 
owners in this and other States have claimed to be done by irriga¬ 
tion on the upper portions of the rivers will become less as time 
proceeds. If the inflow comes from and is due to the rainfall, then 
we cannot look for benefits of this kind, and those on the lower 
reaches cannot hope for a future lessening of the damages. 
§ 45. Such gradual increase of the streams is common in 
countries with considerable rainfall, but the size of the streams and 
the invisibility of the small sources serve to mask it. The lack of 
measurements prevents the fact from being noticed. The rainfall in 
Colorado averages less than fourteen inches per annum. With this 
amount of rainfall, or with the rainfall of exceptional years, would 
there be any return to the stream without irrigation ? 
§ 46. There was no observation of the phenomenon before 
irrigation was practiced. But neither was there settlement. Irri¬ 
gation was practiced for some years on the bottom lands before the 
use of water was sufficient to dry the stream bed, and thus make it 
possible to notice a small inflow, either by its effect on the volume 
of the stream, or by exposing the points of inflow. If there was 
any such inflow, it certainly was not sufficient to prevent the Platte 
from going dry in 1863 and other years. At the time of the first 
