Arizona republican. [volume] (Phoenix, Ariz.) 1890-1930, 1902-04-27


feet per second, with water standing
in the reservoir on a level with the top
of the tunnels. When the reservoir
stands higher than this the head
would, of course, increase the possible
discharge and when water begins to
flow through the spillways the tunnel
would have a discharge capacity of
about 1900 cubic feet per second; and
with the spillways running full, about
$4,000 cubic feet per second. The head
on the lower sill of the outlet tunnels
would be 100 feet, with water standing
at the level of the bottom of the spill
ways. This will be the maximum head
frequently encountered, but the pos
sible head would be 20 feet more, or
210 feet, with water flowing over the
spillWays 20 feet deep, which is con-
sidered the maximum head possible,
encountered only at long intervals if
ever. This will produce a mean pres
sure of about 11,600 pounds per square
foot on the gates, or a total on each
gate of about $50 tons. These pressures
and sizes require gates of great
strength. and efficient means of con-
trolling their position.
Each gate is built of nine parallel
9-inch I beams, two channels horizon
whole enclosed by a half-inch plate
soldly riveted to the beams and chan
| nels. so as to make the entire gate act
as a girder. 1t will be the aim to make
this girder Water-tight on the edges
and the side exposed to the water but
drainage holes viii be provided on the
lower side to discharge any chance
leakage.
The pillar which will occupy the
center CT each tunnel is built of plates
and angles in the form of large 1
beam, and is reinforced on each side by
a twelve-inch L beam, and the whole
| is enclosed by a thin steel skin, to min
inlize the tendency to produce vibra-
tons; and they are so arranged as to
| diminish the contractions also, and
thus increase the discharge. The sheet
steel will be continued along the sides
and bottom of the tunnel throughout
its entire length. Under these arrange
ments the velocity of the water
| through the tunnel, running full, with
the water in the reservoir at the level
Of the top of the tunnel, will be about
seven feet per second, and will in
crease to over 60 feet per second, with
the water 20 feet deep over the spill
ways. Each gate will be worked by
|
through the shaft and tower to the
tower houses at the top of the dam,
| where they will be worked by screws
! operated by electric motors.
| The hollow rods will consist of three
! inch double extra heavy steel drive
| pipe. and will work in guides, as shown
! in the illustration B1.
The upper section of rod which car
ries the thread fer moving the gates
will be solid.
The bearings for the gates will be
upon solid steel rollers placed to elimi-
nate friction. A general view is shown
in drawing Pl.
The steel is estimated at cents per
pound erected.
POWER PLANT.
In the construction of a great dam
one of the most important elements is
that OF power. This is necessary on a
large scale for drilling purposes. for
handling rock, for mixing and handling
mortar, and for crushing rock to be
used in concrete. In the present case,
furthermore, it has been found possible
and very desirable to manufacture on
the ground the large quantity of ce-
ment required in the dam. This would
require about 300 horse power day and
night. for grinding rock and clinker,
and for handling materials and run
ming machinery. 1t is usual to provide
such power by means of steam en-
gines, but in The present case this is
rendered very expensive by the scare
ity Of fuel. Coal, in quantities, now
costs SO per ton in Globe, and the
| wagon haul to the dam site would
nearly double this. A limited amount
of wood is available, but to secure the
large quantity which would be re
quired if it We're the sole dependence
for power would involve long and eX-
pensive haul.
The best means OF providing the nee
essary power is by the development of
water power on the river. This will
involve the construction of a diversion
dam and canal which can afterwards
be utilized, if required, for sluicing ac-
cumulated silt out of the reservoir. The
power developed can afterwards be
used in the neighboring mines or trans
mitted to the valley below for pumping
purposes. For either purpose it will
be a valuable asset.
The standard canal section adopted
has a bottom width of eight feet, water
depth of 3.5 feet. total depth of As feet,
and IL to / in embankment. Its slope
will be .0006.
In the first 1900 feet of the line the
depth will be slightly increased to
provide for seepage losses. Small
drainage lines will be crossed by means
of concrete cuiverts. Flume construc-
ton will be employed only where abb
solutely necessary. on account of its
lack of permanency. The adopted f1ume
section is a rectangular box, four feet
deep and seven feet eight inches wide
inside, built of two-inch redwood plank
supported by frame of native pine. Saw
mills will be esta blished near the line,
and logs floated down Salt river from
the mountain valleys above. This ma
tive timber will also be used for false
works and other temporary structures
about the works.
There are to be two tunnels on the
line, $1,000 and $4,000 feet in length re-
spectively. Both are in coarse gravel