Aberdeen herald. [volume] (Aberdeen, Chehalis County, W.T.) 1886-1917, 1909-01-07

| result Is simply what ii would have
been if big trench had been dug
across the valley down to the stratum
of stiff clay which underlies the dam
site and Lad then been filled with
stone. The work on the dam is not in
any way Interrupted by these small
settings Rock will be dumped until
the toe has reached the desired height
of sixty feet. and each settling will
only result in more rock being dump
, ed there until the solid foundation is
reached and an equilibrium cStab-
liShcd.
The idea that there is Il lake under
the site of Gatun dam probably orig
mated from the fact that the borings
made ut close intervals all over the
dam site revealed water in about 10
per cent of the holes sunk. The re-
suits of these behring's were published
Sept ., 1908. and nothing has dcvel-
oped further. The report on these ex-
plorations. which will appear in the
annual report Of the chairman and
chief engineer to congress, covers the
matter thoroughly from technical
standpoint. Briefly. it shows that wa
ter under pressure was found in sew
eral places under the dam site.
1.-THE fact that there was no cOmmu-
nicatlon between the various holes
shows beyond question that the water
under the dam site is in pockets and
Is not II pool or lake. and the fact that
the water was under pressure .nd rose
in the test holes shows that it has no
outlet. In addition to the borings two
test pits were sunk 100 feet below sea
level. and they merely confirmed what
the bOrings had already shown-that
the dam is being built on very firm
foundation of imperviOus clay.
What is true of the foundation OF
the dam is also true Of the foundation
of the locks. There is no question at
all of it's satisfactory character. The
locks are being constructed in series
of three double locks. making rise
from sea level to the eighty-fiye foot
level Of the Gatun lake. Each lock Is
1000 feet long. no feet broad at the
entrance and Al 1-3 feet deep In fresh
water over the stills.
"rhe excavation for the south or up
per lock is practically completed. and
the concrete work will be begun as
soon as the power handling and mix
ing plants are delivered on the 18TH
mus and can be put In running order
The excavation in the second and third
locks involves the removal of l 100000
cubic yards Of material by steam shOv-
els and 100000 cubic yards 10y suction
lredgcs The steam shovel work is al
ready well advanced. and the dredging
will be begun soon.
''rhe locks will he built entirely of
concrete. forming a series Of three wa
ter tight boxes. each divided into two
parts. Beneath the level Of the floor
W the upper and second locks cur
tain wall will be sunk TO sufficient
depth to keep out whatever water il
now finding or is likely to find its out
let beneath the lock site. The cXcava-
ton on the curtain walls will he begun
in few weeks. Tho plans for the
locks have been completed IN all but
eSsary can be delivered ut the handling
plant in Gatun as soon as they are re-
quired.
'The slide on The relocated line Of
the Panam railroad mt Gatun is SINH
lar tn those which occurred ut Cuca-
racha and at other points along Guile
bra cut and at MiratloreS tunnel. 1t il
caused by the earth. which has become
saturated from the excessive rains and
has been bulalened with the weight of
the fill. sliding on the surface Of the
rock. which underlies it. This slide
has reached its angle OF repose for the
present. hut It is expected thai during
The next rainy season. when the fill is
continued to the ninety-fve foot grade.
the slide will begin again. More mate
rial will hon he dumped into the de-
preston. aud the filing will be con
tinucd until the material has reached
its angle of rcpose. when no further
trouble is expected