The Norfolk weekly news-journal. (Norfolk, Neb.) 1900-19??, 1909-03-19

OHueT 'ts OlNe'
Explaining the settling of the rock
"toc." which started the rumor that
the foundation of the Gatun dam was
sinking ana that subterranean lake
had been discovered under the canal,
as nm event that was expected, n re-
port has been made to the authorities
at Washington which, It is hoped, will
dispel any apprehension.
A portion OF this toe" on the up.
stream end OF the dam sank about
forty feet on Nov. 81. During several
weeks prior to this date n slide under
the high trcstle of the relocated Pan.
anna railroad at Gatun made neces-
sary the dumping of an additional
quantity of rock before the roadbcd
was brought up TO grade. On Nov. 10
the Chagres river flooded the tracks
at Gatun. At the same time the ru.
NOR OF having discovered Il subtcrra.
mean lake on the site of Gatun dam
and beneath, 1t came out. The report
says in part:
"The purpose of the dam at Gatun
is to impound the waters OF the
Chagres IAN artiiciaD lake that will
form In the valley OF the Chagrcs riv-
er. This dam will extend from one
ridge of hills west across the valley
to the ridge on the hills east and will
be one and n half miles long. At the
extreme east end the locks are being
built through a small hill on which
abuts the dam. The dam itself is di-
Vided into two parts, from the site of
the locks to the spillway, the other
from the spillway to the hills west.
The spillway will be located through
a small hill that rises in the middle
of the dam. a temporary spillway
800 feet wide, which will let the
Chagres flow during the construction,
is completed and concrete laid there
early in January. There are three old
channels running through the dam
site.
THE plan for constructing the dam
is to pump sand and clay upon the
site selected until the hill is 1875 feet
above sea level and LOO feet wide
across the valley. This sand and clay
have been found in large quantities
down the Chagres valley, convenient
to the site, and have proved to be
good material for dam. The dam
will be made by suction dredges,
which will pump the material mixed
with water upon the site. and the wa
,f,N.r IF will oil "
homogeneous material. For the pur-
pose of adding weight to the dam and
to prevent material from sliding north
and south. as great mass of earth
is likely to do, two walls. or toes, are
being built across the valley.
"The north or downstream toe Is
composed of rocks and earth taken at
the site of the locks. The south or
upstream toe Is composed of hard
rock taken from the cut at Bas Obs
po. The ridge of Ras Obispo rock is
thirty feet broad Mt the top and when
completed will be sixty feet high, 1t
has reached that height in one place
and has one to one and half slope.
Between the north and south toes
10000 600 cubic yards of clay and sand
from the Chagres valley will be pump
ed The object of these toes is to hold
the material of the hydraulic fill until
the water has drained off.
"The rock wall of the south toe has
been extended to the spillway, closing
the old channel of the Chagres and
east diversion beside the old French
canal, the river finding an outlet
through the east diversion dug by the
French. The old French canal crosses
the Chacres Mt five different places be-
tween Bohio and Gatun, and 1t Is
through that channel that the greatest
part of the Chagrcs flows to Gatun.
"A short distance above the dam the
Eatuncillo flows into the ChaCreS. The
building of the toe forces the water OF
the Gatuncillo and that of the French
channel or canal TO seek an outlet at
n right angle to its natural course, and
II has caused the flats south of Gatun
to he flooded when heavy rains occur,
MS the diversion of the French canal
IS not %ide enough to receive the
quantity of water that flows down the
valley and floods the lower parts. The
hch water Of Nov IL was simply the
repetition of what happened several
times during this rainy season, food
ing the flats of Gatun on the south of
IT, ard it was unusually high, as the
water rose I'm some places as much as
eight inches above the rails,
Halfway between the foot OF the
east hill and the spillway the old
French canal channel runs through
the dam site but 1t has been closed by
the construction Of the south toe. The
silt and soft mud that had collected
I'm the bottom Of this channel for the
past twenty years were not removed
when the construction of the toe was
begun, and when the weight of the
rock became great enough 1t displaced
the soft bottom Of the old channel
and forced II up POO feet north of the
toe into the site Of the dam.
This was anticipated and desired
1t is also anticipated that other parts
of the toe may settle in the same way
The more they settle the firTer will
10 ~, % a.