The Caldwell tribune. [volume] (Caldwell, Idaho Territory [Idaho]) 1883-1928, 1903-04-18

BILE that three may finally be adopted.
as it is safer to lock up and down only
thirty feet as time. If a third lock-
Is introduced perhaps it will not be
located close to the other two, but be
constructed at Tiger Hill. An enor-
nous dam, blocking the course Of the
Chagres, is to be built little east or
the Bohio locks. Engineers say that
there will be less danger Of seepage.
or leakage through the soil, If there is
head of only sixty-t1ve to seventy
feet here. instead Of one of ninety.
Still, If there is another lock at Tiger
Hill the same effect would be secured
A spillway to discharge the surplus
water Of Lake Bohio, will be construct
ed three miles to the southwest of the
dam and locks, on a small tributary
called the Gigantic. A natural cut ex-
lists here, sixty-ive feet above sea lev
Ell. OF course the spillway must be
higher than that to maintain the de-
sired level In Lake Bohio. The COM
mission proposes to have it eighty-f1ves,
feet above the sea. From the Gigantic
the water will drain off through
swamps to the lower Chagres, little
excavating helping the flow here. 1t
Is expected that the Gigantic spillway>
will serve as an automatic safety valve
in time Of foods.
AS already stated, about twelve and
half miles Of route lie through Lake
Bohio. For fully seven miles there
will be deep water. Only little dredg-
ing will be necessary as Gamboa Ia ap-
preached. To the southeast Of the lat
| ter point lies the heaviest work along
the whole route. For nearly eight
miles 7.95, to be exact a cut in the
backbone of the isthmus will be need
ed to bring the canal down to the
proper level. This is known as the
Culebra cut The water will be no
higher here than in Lake Bohio, and
| there will be no locks. However, as it
may be desirable to drain the Culebra
level some time, gates will be intro
duced near Gamboa lat Obispo).
1t may be remarked, in passing, that
the depth of the Culebra cut bears q
close relation to the height of the Bo-
hio dam. The amount of excavation
in the former was lessened twenty feet
when the commission decided to raise
the level Of Lake Bohio to ninety feet
above the sea, instead of seventy feet.
On the other hand, If General Abbot'a
recommendations had been adopted, it
would have been necessary to go TWEEN
ty feet lower in the cut. Part of the
material to be removed here is rock,
but a good deal is merely clay.
Partly to control the excuses of the
Chagres in very rainy weather, 1t has
been proposed to build dam at Alba
juela, ten or eleven miles east of Gam
boa, near the source of the stream. An
artificial lake there would serve as q
reservoir, take care Of part Of the sur
plus water when the precipitation was
heavy, and thus relieve Lake Bohio
of part of it's responsibility. By af-
fording storage. too, it would be able
to reinforce the lower lake in the dry
season.
At the southeastern end of the Guile
bra cut, at Pedro Miguel. there is q
drop Of sixty-two feet, managed by
two locks. At Miraflores, a mile and a
third further, another lock lowers the
level twenty-eight feet more. Beyond
that point to Panama, over four miles.
the canal is at sea level. Dredging in
. Colon Harbor to the extent Of 90 miles
and at Panama for SO miles will add
materially to the work required, but
these figures are not included in the
estimates already given for the canal
proper.