Arizona republican., 1922-03-16

/ The development OF the best reSer-
voir sites on the main branches of the
Colorado river, If used for irrigation
in the lower basin would affect the
conditions OF power development in
their basins below, because the water
would be regulated in accordance
with the needs of irrigation rather
than of power.
Urgency Of Relief
In the valleys of the Lower Colo
rado, and especially the Imperial val
ley, storage is needed for the extern
sion of irrigation and for safety
against drouth of the areas already
irrigated when the cycle of low years
rolls around.
The need is also vital for protection
from floods of the Colorado which
threaten the levees along the river
valley and which are a constant
menace to the Imperial valley threat
ening a repetition of the experience of
1906. Both of these problems are ur-
gent and vital.
The years 1902. 1908 1915 and 1919
were years of low water flow. the
first two being shortly after the be-
ginning or irrigation in the lower val
leys and when the area irrigated was
so small that no shortage occurred
y
ceeded TO a substantial degree.
The records of the Imperial Irriga-
tion system show that for a consider
able period in 1915 the waters OF the
Colorado river were all, or practically
all, diverted at the intake OF that
canal and applied in irrigation of I'm
perial valley, with the result that an
actual shortage existed there part of
the time. The shortage was not Sc
we're nor disastrous but it had a value
as indicating the actual state of the
water supply in relation to use The
shortage would have been still greater
had a period a $ low a s that of 1902
and 1903 occurred at that time.
Since 1915 there has been consider
able Improvement in the application
of water in the Imperial valley but
recent experience shows that storage
is needed to supplement the low water
before any large irrigable areas can
be added.
Since 1915 Imperial valley has in
creased its irrigated area over $4,000
acres in the United States and about
10000 acres in Mexico. The Imperial
irrigation district contains more than
100000 acres of irrigable land not yet
irrigated and the same valley in Mex
leo can increase over 10000 acres and
is in a physical position to take the
necessary water from the Imperial
canal before it reaches the California
line.
The Yuma project is increasing It's
irrigated area. and has a recognized
right to extend up to limit OF 100,-
900 acres.
The Palo Verde valley has in
creased its irrigated area since 1915
by about $4,000 acres and is in phys
ical position to increase this area np
to $4,000 acres.
Two Government projects in Colo
rado taking water from the Colorado
river drainage have increased their
acreage since 1915 about 10000 acres
and have established rights by which
these can be further increased by
over $4,000 acres. In addition to the
above. irrigation users are increasing
in the Uintah and Spanish Fork
basins in Utah and at numerous other
points in the upper Colorado basin,
most of which are small in amount
but which aggregate a. considerable
acreage and will reduce the water
supply OF the lower basin to a sub
stantial degree These NAV be taken
as offsetting the improvements in
duty of water in the Imperial valley
Assembling the more important OF
the known data, We have table c
showing increase over 1915.
This table indicates that the In
creased irrigation in the basin in 1920
over 1915 is about 100000 acres and
tha6the desired expansion in the I'm
perfal irrigation district and incon-
testible or unpreventable expansion
in other regions will bring this acre
age up to SIT 900 acres, or about 400 =
600 acres more than in 1915. besides
the various increases in the Upper
basin.
In addition to this there are large
areas in the Colorado River reserva-
ton, the Mohave valley. and at some
other points where development has
been undertaken. or is likely to be
undertaken in the near future. which
should be taken into account.
The above data are certainly con-
vincing that no large area, such as
the East Mesa lands and Coachella
valley can be added to the irrigated
acreage without certainty Of water
shortage or if so added would consti-
tute a serious menace to the water
supply of the present irrigated lands
in the Imperial and Yuma valleys un-
less a large amount OF storage be pro-
yided-
For. full development Of all the
lands that can be reached by gravity
and reasonable pumping lifts on the
Lower Colorado river, large storage
| capacity will be required estimated
at about 100000 acre-feet. If pro-
vided by a reservoir below the Grand
Canyon in the Colorado. If storage is
provided above the Canyon. this must
! be increased by at least 1000. 900 acre
| feet on account of the unavoidable
losses due to the impossibility of reg
ulating the flow in exact accordance
with the needs of irrigation from a
| reservoir so far distant. and for other
reasons. This capacity can be some
what reduced if the acreage be re-
duced by cutting off the more doubt
full and less desirable acres which
| have been included.
| To remove the menace of flood
from the Colorado river will require a
| much larger storage capacity than
! that above given.
| owing to the gradual upbuilding of
/ IFS deltaic bed and banks, the flood
menace from the Colorado river is an
increasing and eYer-recurring prob
! lem of great importance.
The Gulf Of California formerly eX-
/ tended northW estward TO point a