8 LANDS OF THE ARID REGION OF THE UNITED STATES. 
volume of water running in the streams; the product of these factors giving 
the extent of the irrigable lands. A continuous flow of one cubic foot of 
water per second was taken as the unit, and after careful consideration it 
was assumed that this unit of water will serve from 80 to 100 acres of land. 
Usually the computations have been made on the basis of 100 acres. ‘This 
unit was determined in the most practical way—from the experience of the 
farmers of Utah who have been practicing agriculture for the past thirty 
years. Many of the farmers will not admit that so great a tract can be 
cultivated by this unit. In the early history of irrigation in this country 
the lands were oversupplied with water, but experience has shown that 
irrigation is most successful when the least amount of water is used neces- 
sary to a vigorous growth of the crops; that is, a greater yield is obtained 
by avoiding both scanty and excessive watering ; but the tendency to over- 
water the lands is corrected only by extended experience. A great many 
of the waterways are so rudely constructed that much waste ensues. 
As irrigating methods are improved this wastage will be avoided; so in 
assuming that a cubic foot of water will irrigate from 80 to 100 acres of land 
it is at the same time assumed that only the necessary amount of water will 
be used, and that the waterways will eventually be so constructed that the 
waste now almost universal will be prevented. 
In determining the volume of water flowing in the streams great 
accuracy has not been attained. For this purpose it would be necessary 
to make continuous daily, or even hourly, observations for a series of years 
on each stream, but by the methods described in the following chapters 
it will be seen that a fair approximation to a correct amount has been 
made. For the degree of accuracy reached much is due to the fact that 
many of the smailer streams are already used to their fullest capacity, and 
thus experience has solved the problem. 
Having determined from the operations of irrigation that one cubic 
foot per second of water will irrigate from 80 to 100 acres of land when the 
greatest economy is used, and having determined the volume of water or 
number of cubic feet per second flowing in the several streams of Utah by 
the most thorough methods available under the circumstances, it appears 
that within the territory, excluding a small portion in the southeastern 
