Evening star. [volume] (Washington, D.C.) 1854-1972, 1908-04-12
NEnOFlzMHT ZhE or CoRMsR ,TNaE Z9N1Ve

imposing but scarcely less beautiful than
the Grand Canyon of the Colorado.
The Salt river for more than one hun
dred miles cuts through the widest tangle
OF uplfted mountain ranges in Arizona
mountains that because OF their witness
and their inaccessiblity were for a long
time the chosen home and the last retrea;
of the Apache Indians.
In the deep-cut canyons abe the dam
site are prehistoric cliff dwellings, out of
which fine specimens of pottery and
stone implements have been taken: and
the narrow valley of the Salt river tor
twenty miles above is SCARED with the
outlines of cultivated fields abandoned
long before the handful of white farm
ers came to plant it to the acres of grain
and alfalfa that will soon be lost beneath
the waters of the largest artificial lake
in the world: of thirty miles in length
and nearly two miles in width.
The length of the big dam. w.4ch is
being built on a curve having radius
of about 400 feet. will he 80 feet at the
bottom and 1850 feet at the top, includ-
ing the two spillways. one at each END,
which will each be 200 feet in length,
and will carry off the excess of MOOD
waters for which both streams are noted.
The total height of the dam will be.
from the foundations to top. $50 feet; the
foundations lying thirty feet below the
rive" surface will thus make the clear
height go feet It's width will be loo
d
top Along the entire length of the dam
and spillways will be a good broad road
way.
The dam is being constructed of huge
blocks of stone set in cement. the stone
being blasted from the walls of the cam
yon above the dam. and from where the
spilways will be constructed therein. 1t
will contain $4,000 cubic yards OF
masonry and will be the second highest
dam in the world. exceeded in his re-
Nv no Gov, "a a m
now in construction by the same service
in Wyoming.
When tie big dam is finished and the
Immense reservoir is filled the water VIII
go to 10000 acres of land in the Salt
Eiver valley in Arizona. The waters of
the reservoir are to first supply this land.
The capa city of the reservoir will be
l,301OOO acre feet. and there is also the
amount of the natural steady flow of the
united streams. To guard against the pos
siblities of a drought the reservoir is to
hold supply sufficient for three years,
so the whole supply cannot be used in
any one year. Moreover, the power plant
necessary to the construction of the dam
and maintained thereby is permanent. and
will thereafter be utilized to furnish the
power to lift the water. by means of
pumps and great wells, from the under
ground currents which are known to lie
near the surface. thus supplying from
5000 to 10000 acres more lying near the
sixty miles distant.
Great Mountain Tunnel.
Although the dam is seventy miles from
Phoenix, the lands to be irrigated are
within radius of thirty miles of that
city. This is the longest distance that
water is carried from reservoir to land in
any of the undertakings of the service
This will be accomplished by a most thor
oughly constructed canal. but between the
reservoir and that canal a tunnel through
the solid rock under the mountain. around
one end of that big, brown mass of ma
sonry. curved upstream across the throat
Of the canyon. This tunnel will be 900
feet in length.
The flow into this tunnel will be con-
trolled by six massive steel gates. They
will be the largest ever made, and will be
capable of withstanding a pressure of
1OO pounds to the square inch of their
surface. and will weigh SOo.0U pounds.
When the reservoir is filled these gates
can. If desired. discharge volume Of
water equal IN amount to the entire nor
MAJ flow of the Colorado river, or 10000
cubic feet of water per second.
One of the impressive features OF
the Roosevelt project IS the great pow
err canal constructed as an essential to
the building Of almost every part of the
great work. and which is permanent. to
be hereafter used in operating the great
system.
The government engineers soon dis
covered that the .enterprs would re-
quire the use of at last a quartz of a
million barrels of cement, and that there
were in the rock of the vicinity all the
elements requisite in first-class cement,
and with sufficient power the cement
could be manufactured right on the
ground cheaper than they could purchase