10 
SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
construction of a canal bringing water from the watershed of the 
Laramie river, this canal has been able in 1894 and 1895 to secure 
an amount of water more nearly comparable with the others. 
On the south side of the river the canals are mostlv small, and 
have irrigated essentially the same land and the same amount for a 
number of vears. 
The other canals of the river have not changed to any great 
extent in the amount or the distribution of the land irrigated, 
for eight or ten years. It will be shown later that there is reason to 
suppose that the water passes through the ground at a very slow 
rate. Hence the amount of the land irrigated and the time when 
brought under cultivation will make some difference wdth the 
return waters. It seems probable that the seepage due to much 
of the land under the Larimer & Weld canal, and from the 
Larimer County, as well as all from the North Poudre canal, has 
not vet reached the river. 
t/ • 
The point where the weir is placed at the canon is in a granite 
formation inside the foothills. Within a short distance, the Poudre 
passes out of the granite and cuts across the upturned edges of 
sandstones of the Jurassic and Cretaceous periods, and its course 
from this point until it reaches the Platte is across the 
slight!}^ upturned edges of the strata, vvdiich are mostly shale and 
some sandstone. In some places these form marked ridges across 
the country, extending slightly northwest. Their effect will be 
noticed in the map in the case of the drainage on the north side of 
the Poudre, where many of these small streams extend to the north 
for a long distance. The canals show the contours approximately 
as far up as these go. 
CHARACTER OF THE STREAM. 
§ II. The character of the stream is essentially that of all our 
mountain streams, as its source of water supply is in the 
snows of the mountains. It is low in the spring, increasing from 
April to the middle of June, when it reaches its highest stage; then 
decreasing, reaching its low stage again in September. It remains 
low during the winter. Its maximum discharge may vary from 
3,000 to 5,000 cubic feet per second. Its average winter flow is 
from 50 to 100 cubic feet per second. Its average flow is shown in 
the following table, the averages being made from records of from 
three to twelve years for the different months: 
