SEA-LEVEL CANAL IMPOSSIBLE
No one can dispute the wisdom of the United States in deciding to
build a lock canal. To have undertaken a sea-level canal would have
involved this Government in difficulties so great that even with all
the wealth and determination of America, failure would have ensued. It
is, perhaps, putting it too strongly to say that a sea-level canal is
a physical impossibility, but it is not too much to say that such a
canal would take so much money and so much time to build that the
resources and patience of the American people would be exhausted long
before it could be made navigable.
The advocates of a sea-level canal declared that a channel could be
dug through Culebra Mountain with the excavation of 110,000,000 cubic
yards. As a matter of fact, Culebra Cut, with its bottom 85 feet above
sea level, required the excavation of almost that same amount.
Engineers who advocated a sea-level canal declared that the material
in Culebra Mountain was stable, and that only moderate slopes would be
necessary. As a matter of fact, the material in the mountain proved
highly unstable, and, except for a few short sections, slides and
breaks were encountered all during the construction period. The
result was that practically two Culebra Cuts were dug. The engineers,
in beginning the present canal, calculated that 53,000,000 cubic yards
would be excavated in Culebra; the amount actually removed was
105,000,000 cubic yards. Upon this basis a sea-level Culebra Cut might
have required the excavation of 230,000,000 cubic yards.
Calculating an average monthly excavation of a million cubic yards,
the task would have required 17 years to complete. In other words, if
a sea-level canal had been undertaken and had been physically
possible, the celebration of the opening of the waterway would have
been set for 1925 instead of 1915.
Among all of the members of the majority of the board of consulting
engineers who favored a sea-level canal, only one, E. Quellenec,
Consulting Engineer of the Suez Canal, showed any appreciation of the
difficulties which were to be expected in Culebra Cut. He announced,
in voting in favor of a sea-level canal, that he could not do so
without first reminding the United States Government of the great
difficulties that would lie before it in Culebra Cut. Henry Hunter,
Engineer of the Manchester Ship Canal, declared that Culebra Cut
presented no serious problems at all; that a sea-level cut could be
dug more quickly than the locks of the other type of canal could be
built. He further declared that it was as clearly demonstrable as any
engineering problem could be, that it would be possible to use 100
steam shovels in Culebra Cut. No one has accused the engineers on the
canal of lack of ability in maneuvering shovels, yet at no time were
they able to use more than 46.
If President Roosevelt had followed the recommendation of the majority
of the board of consulting engineers in favor of a sea-level canal, it
seems probable that the United States would have followed the French
in retiring defeated from the Isthmus, or else would have reconsidered
its purpose to build a sea-level canal and have undertaken a lock
canal, as the French had done.
But, even if it had been possible to build a sea-level canal at
Panama, it appears that such a canal would not have been as
satisfactory as the present one. While the canal the United States
possesses at Panama to-day is a great waterway 300 feet wide at its
narrowest part, in which ships can pass at any point, the sea-level
canal projected would have been a narrow channel winding in and out
among the hills, too narrow for half its length for the largest ships
to pass. Currents, caused by the Chagres River, and by the flow of
other streams into the canal, would have made navigation somewhat
dangerous.
The principal ground upon which the majority members of the board of
consulting engineers voted in favor of a sea-level canal was that it
was less vulnerable. This contention, in the light of what has
happened at Panama, seems to carry no great weight. Such a canal would
have required a masonry dam 180 feet high across the Chagres at
Gamboa, to regulate the flow of that river into the canal. This dam,
very narrow and very high, would have been a much fairer mark than the
great Gatun Dam for the wielder of high explosives. Furthermore, while
earth dams, like that at Gatun, have weathered earthquake shocks of
great severity, masonry dams, like that proposed for Gamboa, have
been tumbled to the earth by shocks of much less power. The regulating
works at Gatun will take care of a volume of water approximately twice
as great as the Chagres has ever brought down. On the other hand, the
proposed dam at Gamboa would have cared for only one-third as great a
discharge as the highest known flow of the Chagres.
It was calculated that the lake made by the dam at Gamboa would always
be held at low stage between floods, but if two floods came in quick
succession this might have been impossible. Such a situation would
have made the Chagres River always a menace to the canal, instead of
its most essential and beneficent feature.
Those who objected to the lock type, on the ground that the locks
could be destroyed, seemed to forget that even the sea-level project
demanded a set of locks to regulate the tides of the Pacific. While,
contrary to the usual idea, there is no difference in the mean level
of the Atlantic and the Pacific Oceans, the difference in the tides at
Panama is about 18 feet. This is due to the shape of the Bay of
Panama. As the tide sweeps over the Pacific and into that bay, it
meets a funnel-shaped shore line, which gradually contracts as the
tide travels landward. The result is that the tide rises higher and
higher until it reaches a maximum of 10 feet above average sea level.
When it flows out it reaches a point 10 feet below average sea level,
thus giving a tidal fluctuation of 20 feet. On the Atlantic side the
tidal fluctuation is only 2 feet.
Under these conditions the canal could not be operated during many
hours of the 24 without the tidal locks, if at all, and it would be
almost as great a hindrance to have the tidal locks destroyed as to
have the present locks injured. Another perpetual menace in a canal
with a bottom width of only 150 feet for half of its distance, would
be the danger of a ship sinking and blocking the channel. When the
_Cheatham_ sank in the Suez Canal it wholly blocked the waterway for
nine days, and partially blocked it for a month.
According to the Isthmian Canal Commission, the present canal affords
greater safety for ships and less danger of interruption to traffic by
reason of its wider and deeper channels; it provides for quicker
passage across the Isthmus for large ships and for heavy traffic; it
is in much less danger of being damaged, and of delays to ships
because of the flood waters of the Chagres; it can be enlarged more
easily and much more cheaply than could a sea-level canal. The lock
canal has a minimum depth of 41 feet, and less than 5 miles of it has
a width as narrow as 300 feet. It can take care of 80,000,000 tons of
shipping a year, and, by the expenditure of less than $25,000,000
additional, can increase this capacity by at least a third. It can
pass at least 48 ships a day, doing all that a sea-level canal could
do, and many things that a sea-level canal could not do.
No one denies that if it were possible to have a great Isthmian
waterway at sea level as wide as the present lock canal, it would be
the ideal interoceanic waterway. But, as such a proposition is out of
the question, the American people have at least one thing for which to
thank Theodore Roosevelt--that at a critical time in the history of
the canal project he allowed himself to be converted from the advocacy
of a sea-level canal to the championship of a lock-level canal, in the
face of a majority report of one of the strongest boards of engineers
ever assembled, and prevented a situation at Panama that would have
been humiliating to America, and which probably would have ended for
all time the efforts of centuries to let ships through the American
Isthmus.