Los Angeles herald., 1908-10-25
GROUND WATER
is RANCH KING
WELLS SUPERSEDE CANYON
STREAMS
LARGEST lRRioATING SYSTEMS
PUMP FROM BELOW
Conservative Estimate Indicates Pros
portion of Subsidiary to Surface
Water to Be as Three or
Four to One

In the intensively cultivated horti-
cultural districts which have made
Southern California world famous,
ground-water development for purposes
of irrigation has been increasing in inn
portance for a decade or more. Many
of the largest irrigating systems, which
q few years ago obtained their waters
wholly from mountain canyons, now
depend on their subsidiary pumping
plants to keep up the supply during
summer and fall, and in a number OF
places pumped or artesian waters are
the sole dependence of thriving COM
1nunfties. So extensive has been this
development that q conservative esti-
mate indicates the proportion of under
ground water to surface water now
used during the late summer period
after dry winters, when the surface
supply is lowest and the pumps are
busiest as three or four to one.
In the summer of 1903 w. Z. Men
denhall of the United States geological
survey began field work on series Of
studies of the conditions under which
the ground waters of Southern Cali
fornia occur, as a result of which five
reports have already been prepared.
Relative to Coastal Plain
The earliest issued were three (Wa-
fer-Supply Papers Nos. 1877, 13S and
1890 relating to the coastal plain, which
lies between the coast range and the
Pacific ocean. These papers did not
embody close geologic determinations,
but were rather records of the develop
nents of underground waters which
had taken place at the time of their
issue. A fourth paper (No. 1922, on
the San Bernardino basin, was more
complete and critical and contained
such significant geologic information
as had been brought out in the course
of a rather careful general study of
the valley The fifth of the series has
just been issued as Water-Supply Pa
pr No. 219.
This latest report presents evidence
and conclusions which will be of value
to water users in the important region
that lies along the south base of the |
San Gabriel mountains from Cuca-
monga westward to Los Angeles. The |
belt embraces a small area in the ex-
treme western part of San Bernardino |
county, but 1t lies for the most part |
within Los Angeles county and is con- |
veniently and appropriately designated |
the ''foothill belt"
In the FoothII Belt
The foothill belt comprises only
about 450 square miles of lowlands, but
between $4,000 and 10000 acres (ex-
elusive of the municipalities) are un-
der irrigation, large proportion being
in citrus fruit. This irrigated land
ranges n value from $500 to $1,000 an
acre, and may be conserVatiVely est1- |
mated to be worth $2O,0O0,OO0 to $25,-
100000. In the same area there are
about forty flowing wells and nearly
400 pumping plants, representing an in
vestment of at least $1,00O,000 in wells
and plants alone. It is estimated that
the pumping plants supply the equiva- |
lent of eighty to one hundred cubic
feet of water per second, continuous
flow, used largely for irrigation.
The conditions that affect the occur |
renee and circulation of ground waters
are discussed fully in MendenhalPs re-
port. and the ground-water districts
and irrigation enterprises are described
in detail. Concerning the source of the
ground waters Mendenhall says:
1.-THE statement has frequently been
made that the underground waters are
Just as dependent as the surface run
off on precipitation within the local
contributing drainage basins, but the
tenacity of the oft-asserted belief that
these subterranean reservoirs have
some other source than local rainfall
makes it desirable to repeat this state
ment with emphasis.
Through Tributary Streams
Each of the important subterranean
basins in southern California is sup
piled exclusively by the water which
falls upon it's surface or flows into 1t
through some tributary stream. Any
other hypothesis, as, for example, that
the waters from the distant Sierra or
the Colorado river or the Pacific ocean
may, by underground channels or by
seepage, reach the San Gabriel valley
or the Pomona neighborhood, is err
roneous, and conclusions based on 1t
are wrong and lead to a false policy
in the utilization Of the ground wa
ters."
All of the foothill belt and many
square miles of mountains north of 1t
are shown on three of the United States
geological survey topographic sheets
the Cucamonga, the Pomona and the |
Pasadena-drawn ma scale of about
one mile to the inch. On these maps as
bases all the information in regard to
the water supply of the foothill belt |
that is capable of graphic presentation |
has been assembled, such as lands irrl- |
gated, chief pipe and canal lines of the |
various irrigating companies, pumping |
plants, artesian wells, few OF the do |
mestic wells, ground-water levels lin
dicated by photographic contour lines), |
and artesian areas past and present.
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