520 
ANNUAL, REPORT SMITHSONIAN INSTITUTION, 1919. 
topography and rocky soil and can best be restored to forest con- 
dition. 
The ffreat bulk of the land west of the hundredth meridian which 
is not too high, cold, or rocky for agriculture is arid. Of this 
arid portion, over 15,000,000 acres have been placed under irri- 
gation by private or public enterprise, and in carrying out this work, 
of course, the more favorable opportunities for such irrigation have 
been developed. It will still be possible to add many million acres 
to the irrigated area and perhaps to double the area now irrigated, 
but this must generally be done at high cost, as the cheap opportuni- 
ties have been long since exhausted. There are remaining, however, 
many areas which can be irrigated within feasible costs and will 
develop values far in excess of the necessary expenditures. They 
will furnish healthful homes for settlers and will supply agricul- 
tural products and food resources in proximity to great mining and 
grazing resources, which will be made more valuable thereby. There 
is much room for wise and profitable activity in this line in most of 
the Western States, but the total areas that can be thus reclaimed 
are much less than those offering opportunities in the States farther 
east. 
The following table summarizes the results of the investigations 
made in the western division: 
Projects and extensions of projects investigated by the Reclamation Service 
in the Western States. 
State and project. 
Arizona: 
San Carlos 
California: 
Imperial Valley 
Palo Verde 
Turlock-Modcsto 
Kings River 
Orland extension 
Iron Canyon 
Cuyamaca Water Co. . . 
Volcan Land & Water 
Co 
Jess Valley 
Colorado: 
Grand Valley 
Grand Valley drainage . 
Orchard Mesa 
Uncompahgre 
Irrigable acreage. 
Public. Private. State. 
> 40, 000 
400,000 
15,000 
30,000 
40,000 
260,000 
400,000 
30,000 
225,000 
'2,750 
s 24, 600 
'17,800 
15,000 
30, 000 
9,700 
37,000 
Mean 
altitude. 
Feet. 
1,500 
-200 
250 
95 
225 
245 
230 
400 
500 
4,400 
4,825 
4,650 
4,750 
5,500 
Mean 
rainfall. 
Inches. 
10 
3 
12 
10 
18 
17 
12 
15 
12* 
Probable 
cost.' 
10, 000 
• These estimates must be considered as merely preliminary and subject to change. 
' Indian. 
« Lands not classified; classification shown is assumed, 
< No estimate. 
$13, 600, 000 
52, 000, 000 
5, 000, 000 
5, 000, 000 
12, 000, 000 
2, 500, 000 
30,000,000 
(0 
0) 
1,100,000 
600, 000 
t, 200, 000 
800, 000 
600,000 
Readiness 
for 
construc- 
tion. 
Not ready. 
Ready. 
Not ready. 
Do. 
Do. 
Ready. 
Not ready. 
Do. 
Do. 
Do. 
Ready. 
Do. 
Do. 
Do. 
