Hicks on Irrigation of the Niobrara Valley. 73 
pai-ed for the enormous differences in the practice of irrigators 
in different parts of the same country. In England one cubic 
foot of water per second is sometimes applied to a single acre,, 
and in other places that amount is made to serve ninety acres. 
The usual "water-right" in Colorado is one and a half cubic 
feet for eighty acres, or 53^ acres to the cubic foot per second. 
"In California a cubic foot of w^ater is said to be capable 
of irrigating more than 100 acres, in India 200, and in Spain 
and Italy a much larger area.'" "A continuous flow of one 
cubic foot of water per second will, in most of the lands of Utah,, 
serve about 100 acres for the general average of crops cultivated 
in that country."^ 
In the absence of direct experiments in the valley of the 
Niobrara, I shall assume that 100 acres may be irrigated by one 
unit of water. This will give 9,800 acres for the total amount 
of land which may be irrigated from the upper course of the 
Niobrara, if the measurement given above is a fair index of the 
capacity of that stream. But cannot its Avaters be used over 
and over, thus multiplying by a score or more this 9,800 acres? 
This is a question of great practical interest and importance. 
Supj^ose the irrigable land lying in a section of this valley ten 
miles long amounts to 9,800 acres, and will absorb all the water, 
will not this water return to the bed of the stream and be ready 
to irrigate the next section of ten miles? Probably 175 or 200- 
miles of the Niobrara valley in Nebraska is available for irriga- 
tion, and if the river can be used every ten miles then it can be 
used, say nineteen times, and made to supply 186,200 acres. 
But in this computation we are reckoning without our host. 
A very small portion of the water used in irrigation ever re- 
turns to the bed of the stream from which it was taken. It 
disapi^ears by evaporation, by percolation, and by absorption in; 
the tissues of plants. Evaporation occurs all along the ditches 
and trenches, all over the surface of the fields, and from the 
leaves and stems of the growing plants. Vegetation is so largely 
composed of water taken from the soil (no less than 75 P^"^' 
cent, of ordinary terrestrial plants is water, according to Prof C- 
E. Bessey) that the vapor of water is constantly escaping from 
1 J. W. Powell, Lands of the Arid Region, p. 143. 
2 Ibid., p. 84. 
