Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1902-12-19
The Water Supply for the lsthmian
Canal.

The investigation of the water sup
ply for the isthmian canal was as i'm
portant a factor in the selection of the
route the survey of the physical
features of the country through which
it must pass If the original intention
of the French engineers to make the
canal a Underwater passage had been
carried out, the water supply of the
country would not have been a factor
to be considered. except for the embar-
rossment occasionally caused by eX-
IRENE floods which might find their
way into the canal. But when the
tide-water project was abandoned and
it was decided that canal crossing the
continental divide by means of locks
with a summit level of nearly 100 feet
above the sea was the most feasible plan
of construction. it became of the utmost
Importance to determine whether the
natural supply of the region in the form
of nearby streams would be sufficient
to provide the amount of water neces-
sary to operate the canal. There will
obviously be a constant drain on the
waters of the summit level with every
vessel passing through the locks, which
will be so considerable that large guam
titles of water must be secured to re-
plenish it, Careful estimates have
placed this amount necessary to meet
the losses from lockage, power, leakage,
and evaporat ion-the last being by no
means an unimportant factor in a tro-
pcal clmate-at an amount equal to
a constant flow of 100 cubic feet per
second.
Such an investigation was carried on
by the isthmian commission for a num-
Der of years and included both the re-
gions of the Nicaragua and the Pana-
ma routes. The results of this work
show that the feasibility of the Pana-
ma route rests upon the magnitude and
habit of the Chagres river, from which
it must draw its supply for the sum-
nit level, and from which its lower levels
| will be in danger in times of flood. To
| a less degree the Grande River at the
southern end of the line is of similar
| importance.
Before the Panama route could be
| definitely recommended several import
and facts regarding the Chagres river
| had to be determined. First, the
| amount of its minimum flow, to find
| how little water might be expected at
| certain seasons to feed the summit lev
| ell; second, the magnitude of its flood
| discharge. to show how much surplus
| water would have to be disposed of In
| times of freshet without injury to the
| canal or detention to its traffic; third
| the possibility of storing water in res
| ervoirs for use in times of low water
| and fourth, a knowledge of the rain
| fall of the region, on which the flow OF
the streams depends.
The projected canal from Colon TO
| Panama is AZ miles long, and for more
than half its course 1t follows the val
ley OF the Chagres river. Although
the country is covered with heavy veg
citation. the slopes are so precipitous
and the rock is so near the surface thai
violent tropical rainfalls lasting only 6
few hours cause heavy and sudder
floods. This is the feature which makes
the study of the flow of the lower
Chagr of such Importance.
The rainfall, though copious, wa:
found to be peculiar on account of the
striking difference in its amount on .h'
northern and southern sides of the 18th
mus the mean yearly rainfall at Color
being 1870 inches, while that at Panama
less than 70 miles distant, was only &C..
inches.