62 
SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
8. 1 he passage of the seepage water through the soil is very 
slow, so that it may take years for the seepage from the outlying 
lands to reach the river. y s 
9. The amount of seepage is slowly, but constantly, increas¬ 
ing. 
10. It may be expected to increase for some years to come. 
11- An increased amount of land may be bought under cul¬ 
tivation, with time, more especially on the lower portions of the 
streams. 
12 The seepage being nearly constant throughout the year, 
while the needs are greatest in summer, the use of storage will best 
utilize the water from inflow. 
13. The seepage from one thousand acres of irrigated land on 
the Poudre river gives one cubic foot per second constant flow; on 
the Upper Platte, one foot to about 430 acres ; on the Lower Platte, 
one foot to 250 acres. The difference is due mostly to the greater 
distance for the seepage to reach the main stream, and to the time 
and amount of water applied. 
14. One cubic foot per second of inflow is obtained on the Pou- 
die rivei for each 2,400 acre-feet applied, or the inflow is about one- 
third as much as the water applied. 
15 \ On the Poudre river about 30 per cent, of the water 
applied in irrigation returned to the river. 
16. The use of water on the upper portions of a stream, when 
water is not immediately needed by prior appropriators, will 
increase the flow of the stream late in summer and prevent such 
low stages as it would have without this regulating action. 
17. The seepage water is already an important factor in the 
water supply for the agriculture of the State. The capital value of 
the water thus received in the valley of the Cache a la Poudre alone 
is not less than $300,000, and perhaps $500,000, and for the Platte 
is from $2,000,000 to $3,000,000. It is large for the other streams, 
but or unknown amount. 
-m x actua * l° ss i s incurred in carrying a stream like the 
Platte through sandy beds. 
19. Ultimately, the returns from seepage will make the lower 
portions of such valleys as the Platte more certain of water, and 
probably enable a larger acreage to be grown. 
,. . ^9* results here shown may be expected to apply with 
limitations to other valleys similarly situated, where irrigation is 
