The Scranton tribune. [volume] (Scranton, Pa.) 1891-1910, 1902-12-26
CANAL PRELlMINARIES.
An idea of the Extensive Hydro
graphic Work Necessary Before
the Isthmian Route Could
Be Determined

The investigation of the water sup
ply for the isthmian canal was as i'm
portant factor In the selection of the
route as the survey of the physical
fea lures Of the country through which
it must pass. If the original intention
of the French engineers to make the
canal a tidewater passage had been
carried out, the water supply of the
country would not have been q factor
to be considered, except for the en-
parrassinent occasionally caused by
extreme 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 re-
gion in the form of nearby streams
would be sufficient to provide the
amount OF water necessary to operate
the canal. There will obviously be Il
constant drain on the waters Of the
summit level with every vessel passing
through the locks, which will be so
considerable that large quantities of
water must be secured to replenish ii.
Careful estimates have placed this
amount necessary to meet the losses
from lorkage, power, leakage, and
eraporation--the last being by no
means an unilnDortant factor in q
tropical climate-at an amount equal
to Il constant flow of 1,07O cubic feet
per second
Such an investigation was carried on
by the Isthniun commission for a num-
bcrof years under Arthur +. Davis. of
the United States Geological Survey.
as chief hydroSrupher and included
both the regions Of the Nicaragua and
the Panama routes. The results of this
work are of much interest and will
shortly appear in the twenty-second an
nGal report OF the United States Geo
logical Survey, Part ", which is now
in press. From this comprehensive re-
port it is seen that the feasibility of the
Panama route rests upon the magni-
,ude ana habit OF the Chagres river.
from which it must draw it's supply for
the summit level. ana from which its
lower levels will be in danger in times
of flood. TO Il less degree the Crane
river. at the southern end of the line is
Of similar Importance.
Before the Panama route could be
definitely recommended several inipor-
tant facts regarding the Chagres river
had to be determined. First, the
amount of it's minimum flow, to find
how little water might be expected at
certain seasons to feed the summit
level; second, the magnitude OF it's 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 reser-
No!rs for use in times of low water: and
fourth, Il knowledge of the rainfall of
the region, on which the flow of the
streams depends.
one of the first steps taken in the in |
vestigation was Il careful review in
Paris of the records OF rainfall and
stream flow kept by the engineers of
the French Panama canal companies
both first and second, which, though
fairly complete, We're found lacking in
respect to flood records. The next
step was 10 verify and extend these
observations. This was done by estab-
iSiiiAS SddSiiiS SlSttlbHS, WfleTt tuFGIul
We're made of the
OF flow by means of current
meters and float rods and by cages set
In the stream TO record it's daily heights
ana fluctuations, from which the maxi
mum, minimum, ana mean discharges
We're computed
The projected canal from Colon to
fanama Is forty-seven miles long. and
Tor more than half its course it follows
the valley OF the Chagres river. AL
though the country is covered. with
heaVy vegetation. the slopes are so pre- /
cipitous and the rock is so near the sur-
face that violent tropical rainfalIs last.
ing only few hours cause heavy and
sudden floods. This is the feature
which makes the study of the flow of
the lower Chagres of such importance
The rainfall, though copIo,ls was
found to be peculiar on account of tbe
striking difference in It's amourt m
the northern and southern sides Of +ha
lsthmus, the mean yearly rainfall ot
Colon being l30 inches, while that ot
Panama, less than seventy miles dis
tant, was only &c & inches |