Arizona republican., 1905-08-21
S. V.WATER TABLE
A Report on the Valley S
Underground Flow
The Result OF a Detailed Investigation
by willis 7. Lee Of the Geological
Survey.

Washington, Aug. 2O.-Mr. Willis T.
Lee of the United States geological
survey has recently made a detailed
investigation of the underground wa
ters and geology of the Salt River
Valley. Arizona. in the Phoenix region
and eastward. and submits the results
in a paper which is now going through
the press The purpose of the investi-
cation was to ascertain the available
quantity of underground waters in this
locality, the areas where they occur
sufficiently near the surface for eco
nOmic pumping. and their adaptability
for irrigation.
The area Of special investigation lies
within a line drawn from the junction
of the Verde and Salt rivers westward
a few miles beyond the Auga Fria
and southwark to Gila river. thence
along the northern border of the Pima
Indian reservation to the Superstition
mountains. north of Florence, and
along the foot of these mountains to
the mouth Of Verde river. an area. ir-
respective of the mountains, of about
1000 square miles.
After giving in detail the records OF
all the Individual wells known in this
area and discussing the geology and
physiography of the region. Mr.. Lee
deYOtes himself to a consideration Of
the economic features of his problem,
including the area of profitable pump
ing, the chemical character and guam
tity of ground water the cost OF
pumping, the best location for pump
ing plants. and the value of water pro-
cured by pumping
The plain of which Salt River Valley
is a part is due principally to upland
accumulations. In the process OF accu-
mutation the lowest outlying hills
were buried and the higher ones. be-
ing only partly buried, are now found
rising abruptly from the level plain.
The valley fill is saturated with water
and the various beds of gravel are so
intimately connected that the water
rises to a definite level, forming a
well defined water table. The under
ground waters are derived mainly
from the occasional floods that enter
the valley from the surrounding hills.
The valley fill is more or less impreg-
mated with various salts derived from
the waters of Salt river in former ages
and deposited with the detritus. AL
though some of the underground wa
ters of the valley contain salt in guam
titles which may be harmful to land
under certain condition, it is prob
able that with proper manipulation all
of the waters can be safely used.
The principal water-bearing hori-
zon is about fifteen miles wide IN the
Mesa region and extends to a depth
of over 200 feet. The distribution of
the gravel beds and the depth TO the
water table are such that pumping for
irrigation can probably be carried on
with profit over an area of 525 square |
miles. The underflow returns in part I
to the surface in certain places in the |
valley, making a surface flow estimate
ed at something over 100000 acre-feet /
a year. The quantitative estimate of
the underflow, based on experiments, |
indicates a volume of flow of 1876 |
to 287,160 acre-feet a year. At this |
rate something less than ninety-siX !
pumping plants of the average capac-
ity GOO inches) could be operated con- |
and retain the water level |
within pumping distance of the sur
face. The volume of the reserve of |
Salt River Valley is conservatively |
estimated at from $500, 900 to 1900, 600 |
acre feet.
The cost of pumping water in Salt !
River Valley varies from "a to 1873 |
cents per acre foot per foot of life, or
from $3.50 to about So per acre-foOt |
of pumped water. Since fuel is the !
greatest item of expense, the cost |
could be greatly reduced by the use of
electrical power, which might be fur
nished for about $50 per horsepower a
year. At this rate the best pumping |
plants of Salt River Valley can raise
water at a cost Of IL cents per acre |
foot per foot of lift. or an average cost
per acre-foot of pumped water of about
75 cents for the present lift. The val
ue of an acre-foot of water APPLIED to
in
from $3.65 to $56.45.
The volume of underflOw is capable
of extended development. but there is (!
danger that a greater draft will be
made upon it than is consistent with
the maintenance of the water level
within. practical pumping distance.