El Paso herald. (El Paso, Tex.) 1901-1931, 1911-05-26

~ ATUN, Canal Zone, Panama. May
= 26.-The integrity Of the Pana-
ma canal viii depend upon the
stability of the dams that are to hold
in check the billions of gallons of
water in the great artificial lake
through which about 30 Of the 90 miles
o. channel will run at a level Of IS
feet higher than the sea.
The water in this lake will be
brought down from the watershed of
the Chagres river, a natural supply,
but If it were not for the dams, 80
miles of the big ditch would be high
and dry. 1t will devolve upon the dam
at Gatun to restrain the nearly 2,00O,-
900, 600 cubic feet of water in this lake,
the surface of which will be more than
100. 900 acres in extent. The shape o.
the lake may be nkened to that Of an
irregularly outlined gridiron. the han
die representing the Culebra cut
through the mountains, and the gr-.
the main body of the lake.
Largest Dam In world.
Interest in dam construction at Pan
ANA centers in the one at Gatun, be-
cause 1t is the largest dam in the
world, and also because of the great
controversy that was wased for sc
long as to whether or not 1T would be
stable. The dam is half a mile wide
and a mile and a half long. Tt closes
up the Chagres valley completely. one
end resting on a small mountain west
of the Chagres river and the other
end abutting on the locks at the east
across the valley there is minor
ridge running. parallel with the hills
which wall the lowland. This has
been christened "Spillway HIP by
the engineers, and on its crest is To-
Gated the spillway which will carry
all surplus water from Gatun lake to
the sea.
The Gatun dam will not be as high
as was originally planned. Two
years ago the world was startled by
a report sent out by a Panamanian
yellow journalist that the Gatun dam
had given way, although there was
then no dam there to give way. This
report so stirred the country that
president Roosevelt sent a commits
sion Of the best engineers in America
to visit the isthmus and examine the
work with the utmost thoroughness-
The net result was a unanimous YER
dict that Gatun dam was being built
uselessly big and that useless pre-
cautions were being taken The COM
mission recommended that the dam be
cut down from 135 feet height to 1l5
feet, and that the interlocking steel
sheet piling which it had been in
tended to drive into the foundation
of the dam be omitted as an unnec-
essary precaution-
The result is that today the Gatun
dam is a mile and half long. 115
feet high, half mile thick at the
base. 400 feet thick at the water line
and 100 feet thick at the top. The
water in the lake Will have normal
level of IS feet. so that the top OF
the dam will be 80 feet above the
ordinary lake level
! An Erroneous Impression.
The average conception of the Ga
tun dam as a high wall of mud. or as
an artificial mountain with precipit-
Gus sides is entirely erroneous Its
slope is so gradual that it is hardly
noticed in the landscape. Take
yardstick and raise the end three
inches higher than the other, and the
resulting slope viii be considerably
greater than the average of that of
Gatun dam. Its slop Is less than one
third of that of many Of the sur
rounding hills.
The work Of constructing the Ga
tun dam is proceeding with wonder
full dispatch It will contain some
20, OOe, 900 cubic yards of material. and
considerably more than half of that
amount already is in position Dur
ing the fiscal year 1910 more than
(. 00O,OOO yards or materlaI were pidCeu
in the dam. Construction was begun
by building two lines of stone retain
ing walls across the valley, 1900 feet
apart Between these two walls, which
are known technically as the toes
of the dam, millions of cubic yards OF
sand and clay are being pumped to
make the core of the dam. This is
being done by huge, 20-inch eentri-
fugal pumping dredges. AS the dam
rises from It's foundations large
pond will be maintained on its crest
into which the materials will be
pumped The water will run off and
the material ii contains will remain
on the dam.
Is Water-tisht and Safe.
In this way the engineers have