IRRIGABLE LANDS OF THE COLORADO DRAINAGE. 163 
engineering skill required would be beyond the resources of any ordinary 
settlement. 
Gunnison Valley—In Gunnison Valley, below the foot of Gray Canon, 
are 25 square miles of arable land. The cost of constructing the necessary 
irrigation works at this point would be greater than above the mouth of the 
Uinta, but still not beyond the ability of a colony. Green River flowed in 
Gunnison Valley in September, 1877, 4,400 cubic feet of water per second, 
enough to irrigate at the standard adopted 860 square miles. There seems 
to be no arable land to which it is possible to take this great surplus, and 
probably for many years to come it will be suffered to flow ‘‘unvexed to 
the sea” 
The area colored on the map is much greater than above indicated. 
The selections of irrigable lands will be made on either side of the river, 
in patches, within the colored district. 
THE GRAND RIVER. 
The Grand River has but a small amount of arable land along its 
course in Utah, and flows for most of the distance in a close canon. The 
volume of the stream, about 40 miles above its junction with the Green, 
was measured in September, 1877, and found to be 4,860 feet per second. 
It is probable that selections can be made to the extent of 40 square miles 
from the areas colored on the map. 
THE SAN JUAN RIVER. 
But little is known concerning the arable lands or volume of water in 
the valley of the San Juan. It flows for the most of its course through 
Utah in a cafion, and all the arable land is thought to be so much subject 
to overflow that cultivation is impracticable. 
OTHER STREAMS. 
A few smaller streams are also tributary to the Colorado and Green 
within the Territory of Utah, but they mostly flow in deep canons, are often 
dry in some portion of their course during every year, have at best only 
a few acres of arable land anywhere along their courses, and have been 
omitted in this report. 
