206 GUIDEBOOK OF THE WESTERN UNITED STATES 
that the first orange orchard and the first olive grove in the Salt River 
Valley were planted. Of cantaloupes and melons the annual output 
is nearly 6,000 carloads, and of lettuce about 10,000 carloads. Figs 
and dates are important products, and other small fruits are raised in 
great variety and large amount. 
Much water for irrigation, city water systems, and individval ranches 
is pumped from shallow wells in the gravel and sand that underlie 
the Salt River Valley. These deposits contain a large volume of 
water, mostly the general underflow from the Salt and Gila Rivers 
to which is added some of the local flood water entering the valley. 
It is believed that although most of the rainfall is lost by evaporation 
or run-off, a part of it as well as considerable water that has been used 
for irrigation sinks into the porous material of the valley floor and 
in a measure replenishes the underground supply.7 The amount of 
underground water available varies from place to place with the thick- 
ness and character of the permeable beds, and in some localities heavy 
pumping has depleted the supply. It is estimated that 525 square 
miles in the Salt River Valley is underlain by water-bearing beds 
from which the water can be profitably utilized by pumping.® About 
Mesa the area of water-bearing beds is 15 miles wide and some of 
them extend to a depth of 200 feet. 
In the Salt River Valley as in other similar districts there are two 
principal kinds of alluvium—the coarse river deposits of many sorts, 
laid down at various stages of the rivers, in old and new channels, and 
under different conditions of velocity; and the finer sheet wash 
rate of 2 to 3 miles a year has been 
alley fill and other permeable material | estimated. (Meinzer.) 
i * A detailed study of these under- 
ud of the ground water resources was made by 
of a mile a year, or one-eighth of an | the U. §. Geological Survey in 1900— 
_ inch 4 minute, is a fair average; in the | 1903. (See Water-Supply Paper 136, 
: sands of the rivers and wash deposits a | by W. T. Lee.) 
