Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1914-08-05
By WILLIAM R. SCOTT

As o. per rent Of the vessels IN the
world are Iess than 900 feet long II
would be great waste of water and
time TO use the full 1000 foot lock In
each passage, SO intermediate gates
are being constructed which will per
NIT the use " only 400 or GOO feet. as
the particular vessel may require
There are recesses In the lock walls
which allow the gates 'to.'be opened
and still leave clear width OF ITO
feet AT the entrance Of the locks a
chain, with links three inches In di-
ametar. stretches from one. side 10 the
other to stop vessels which might not
obey the signals In case the first
gates should be rammed and broken
a second set Of gates especially pro-
vtdpd for emergencies have been con-
structed behind the first set II both
sets of gates should be demolished tue
water would rush through with fear
full velocity. but provision has been
made against this contingency by hay.
ing I'm readiness emergency dams.
which would be swung out over the
lock and forced down through the In
rushing water. .-s:- /.
Ii Is to prevent such accidents that
the plan OF towing vessels through the
locks with electric locomotives WAS
adopted. as then no misunderstanding
Of signals from the captain to the en-
gineer OF a ship could result. The
tracks for these locomotives are on
each side wall OF the locks. and two
will fasfen to the rear and two to the
front OF ship to effect a passage. II
all twelve locks were Joined end to
end they would make n canyon nearly
three miles long. no feet wide and
eighty feet deep. .' 80 ..,.'...
The natural topography OF the 18TH
mus at Ilanama permitted the Chagres
river TO sstiipe into the Caribbean sea
through y break in the monntains at
Gatin. Engineers logically. considered
that this was the point at which dam
should be thrown acrtHs the Chagres
river. Two valleys we're formed at
Gatnn by hiil which rose. in the
camer TO an elevations OF 10 feet. and
the dam that was designed runs from
the tiatun locks to this hill and from
this bill to the monntains. total dis
lance OF 1900 feet. or a mile and
half.
As the Chagres river every year dis
charges enough water to flI the lake.
some means of dIspositig Of the sur
plus water had to be provided. The
plan adopted called for a spillway to
be constructed In this hill, about third
way In the dam site. This splllway is
Of concrete. requiring z25,O00 cubic
yards to complete On July l. 1913. 1t
was more than 9s per cent completed
1 The door of the spillwa! is ten feet
above, lsea level and 300 feet wide
through the hlll. which involved ex.
cayation through rock fer a depth Of
100 feet at the highest point of the
bill A concrete dam was built on
this floor to a height Of sixty nine feet
above sea level and In shape like a
semicircle. On top of the concrete
dam piers were built With an arrange
ment for. steel gates These steel
gates viii be electrically operated and
regulate the flow of water out Of the
lake. AS much as 14OOOO cubic feet Of
water per second may escape through
the Spillway when the gates are open
There will not he a complete loss Of
this water. as on the east side Of the
spilIway a power plant OF the hydro
electric type will be- operated 4 drop
OF. serpnty-five feet by the water will
operate turbine engines. which in turn
will operate the electric machinery that
wifi generate all the power and illumi-
mating current needed from one end Of
the canal to the other. But an addi-
tional power plnnt will be maintained
Mt Mir;ifiores for emergencies. The
power tn operate the lock gates will
come from the spiIlway plant.
The Gatnn dam is so stupendous that
Il almost seems to be a continuation Of
the hflls that inclose the lake 1t In
fact does complete the natural noun
tain chains that form the barriers or
the Chagres river It Is lOs feet high.
or twenty feet above the ordinary level
Of the lake at eighty-fye feet eIeya-
don The plan of construction has
been to build parallels mounds for the
mile and half. loo feet apart Be
tween these mounds. built Of rock and
earth. q core for the dam has beeHcon-
'tructed By pumping mud and sand
rom the bed Of Chagres river About
70 per cent Of the material pumped Is
'olid matter. and when Il has deposited
he water Is pumped on. This opera
ion has been repeated until an imper-
Tious heart has been made In the dam.
Even Z water from The lake nenetrnfei