IRRIGABLE LANDS OF THE SALT LAKE DRAINAGE SYSTEM. 115 
flow the reclamation of one hundred acres of land, with the belief that the 
consequent estimates would never underrate, though they might sometimes 
exaggerate, the agricultural resources of the districts examined. 
In the measurement of streams the following method was employed : 
A place was sought where the channel was straight for a distance equal to 
several times the width of the stream, and where for some distance there was 
little change in the dimensions of the cross section. Measurement was 
then made of the width (in feet), of the mean depth (in feet), and of the 
maximum surface current (in feet per second). The mean current was 
assumed to be four-fifths of the maximum current; and four-fifths of the 
product of the three measured elements was taken to give the flow in cubic 
feet per second. ‘This method of measurement is confessedly erude, and is 
liable to considerable error, but with the time at my disposal no better was 
practicable, and its shortcomings are less to be regretted on account of the 
variability of the streams themselves. 
All of the streams of Utah that flow from mountain slopes are subject 
to great fluctuations. They derive a large share of their water from the 
melting of snow, and not only does the melting vary as to its rapidity and 
season, but the quantity of snow to be melted varies greatly from year to 
year. A single measurement standing alone is quite inadequate to 
determine the capacity of a stream for irrigation, and as it was rarely 
practicable to visit a stream more than once, an endeavor was made to 
supplement the single determination by collating the judgments of residents 
as to the relative flow of the several creeks and rivers at other seasons and 
in other years. In districts where the water is nearly all used and its 
division and distribution are supervised by ‘ watermasters ”, those function- 
aries are able to afford information of a tolerably definite character, but in 
other districts it was necessary to make great allowance for errors of 
judgment. Certainly, that element of my estimates which is based on 
inquiries cannot claim so small a probability of error as the element based 
on measurements. 
Streams that are formed in high mountains reach their highest stage 
in June, and their lowest in September or October. Streams from low 
mountains attain their maxima in April or May, and reach their low stages 
