The Kalispell bee. [volume] (Kalispell, Mont.) 1900-192?, 1902-11-25

lstnmlan canal was as important a
factor in the selection of the route
as the survey of the physical features
of the country through which it must
pass, says Director Charles D. Wal
colt of the United States geological
survey in his report on the project.
| If the original intention of the
French engineers to make the canal
a tide water passage had been car
ried out, the water supply of the
country would not have been factor
to be considered, except for the en-
barrassment 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 cross
ing the continental divide by means
of locks with a summit level of near
ly 100 feet above the sea was the
most feasible plan of construction, it
became of the utmost Importance to
determine whether the natural sup
| ply of the region in the form of near
! by streams woulu be sufficient to pro-
vide the amount of water necessary
to operate the canal. There will OBJ
viously 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 quantities of water must
be secured to replenish it. Careful
necessary to meet the losses from
lockage, power, leakage and evapora-
tion-the last being by no means an
unimportant factor in tropical eli
mate-at an amount equal to con-
. slant flow Of 1,070 cubic feet per
second.
Such an investigation was carried
on by the Isthmian committee for a
number of years under Mr.. Arthur P.
Davis of the United States geological
survey, as chief photographer, and
included both the regions of the Mic
aragua and Panama routes. The re-
suits Of this work are of much inter
est and will shortly appear in the
twenty-second annual report of the
United States geological survey, part
4, which is now in press. From this
comprehensive report it is seen that
the feasibility of the Panama route
rests upon the magnitude and habit
of the Chagres river, from which it
must draw it's supply for the summit
level, and from which its lower levels
will be in danger in times of flood.
To 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 i'm
portant facts regarding the Chagres
river had to be determined. First
the amount of its minimum flow, tc
find how little water might be ex
, pected at certain seasons to feed the
summit level; second, the magnitude
of it's flood discharge, to show how
much surplus water would have tt
be disposed of in times of freshe
, without injury to the canal or deten
! ton to it's traffic; third, the POSSIBLE
ity of storing water in reservoirs foI
r use in time of low water; fourth, {
8 knowledge of the rainfall of the re
. gion, on which the flow of thu
/ streams depends.
One of the first steps taken in thu
/. investigation was a careful. review il
6 Paris of the records of rainfall an,
! stream flow kept by the engineers o
i the French Panama Canal companie
# both first and second, which, though
? fairly complete, were found lackin
in respect to flood records. The mex
step was to verify and extend thes
observations. This was done by es
tablishing gauging stations, wher
careful measurements were made c
E. the amount of flow by means of GU
n rent meters and float rods and b
II gauges set in the stream to recor
e. its daily height and fluctuations, frol
II which the maximum, minimum an
r mean discharges were computed.
c. The projected canal from Colon
IL Panama is AZ miles long, and fc
r. more than half its course it follow
the valley of the Chagres river. A
though the country is covered wit
heavy vegetation. the slopes are s
es precipitous and the rock is so nes
s. the surface that violent tropical raj
or falls lasting only a few hours caus
I'd heavy and sudden floods This
ar the feature which makes the study
the flow of the lower Chagres of sue
Importance.
The rainfall, though copious, W;
found to be peculiar on account
at the striking difference in its amour
be on the northern and southerly sid
'e- of the isthmus, the mean yearly raj
Ell - Ill 4 Z. 1.