The Elbert County tribune., 1915-12-24

long before the area involved could be
reached Like the east side, sluicine
away from the direetion OF the prism
is impracticable.
The conclusion reached, therefore.
was that the only method of handling
the slides ON the two banks is to re-
move. the material from the prism by
dredges as 1t comes in. The breaks
on the two banks are clearly defined.
and Judging from experience with
other slides and breaks. the limits OF
the movement have been reached.
Confirmed by Biologists.
Mr. Macdonald. the geoiogist for
merly employed. passed through hare
on his way to Costa Rica three weeks
ago. and. after going thoroughly over
the slides. reached the same conclu-
sions as to The limits to which the
siding would take place. and the
methods employed for handling the
material. His profession. his intimate
knowledge of the formation of the To-
cality and his experience with the va
rious slides and breaks make his opin-
ions on the subject of value He also
expressed the belief that the troubles
due to slides would end with the re-
inoval of the material from those In
progress.
When the break occurred in Octo-
Der. 1914. and the subsequent breaking
up of the west bank became evident.
1t was decided to augment the dredg-
ing fleet by another 15-yard dipper
nd IL nfF II
barges. all of which are now in serv-
ice. and the dredges are handling at
the slide nearly a million cubic yards
per month at cost less than 80 cents
per cubic yard.
AS to the amounts involved. it is
difficult to make any reliable esti-
mate. AS already stated when the
break occurred at Cucaracha in 1913.
it was estimated that 100000 cubic
yards were involved but before the
movement ceased 4.679 23S cubic yards
were taken out by steam shovels and
dredges, in addition to upward of a
million cubic yards of material which
would have entered the prism had it
not been removed by sluicing
The length of the slides. which
are directly opposite each other. is
approximately 2.200 feet tthe channel
through which is navigable with the
exception of 500 feeD; the banks are
300 to $50 feet above sea level on the
east and extend up to 4SO feet above
sea level on the west. The area of
the territory affected on the east side
covers 81 acres and on the west side
7S.5 acres.
Must Reach Angle of Repose.
Assuming that all material, lying
above planes extending from the out
side limits of the bottom of the prism.
referred to, up to the limits of the
breaks, will move into the cut, 7000.-
600 cubic yards will have to be re-
moved before the slides are entirely
stopped. Mr.. Comber, resident engf.
neer of the dredging division, as
sumed surface parallel to the sur
face, existing on October IA, the date
of the last complete survey, and As
feet below it, on which basis 13. .OOO, 600
cubic yards would be the quantity to
be handled. He thinks. however, that
mean between the two amounts may
be more nearly correct, which was the
method of arriving at the 10000. 900
cubic yard figure which has appeared
in the press. 1t is at best only a
guess
1T must not be inferred from this
that the canal will be closed until this
amount is dredged, for such is not the
case; on the contrary. it is the inten-
ton to pass ships as soon as a channel
is secured through the remaining 500
feet, and there are reasonable grounds
for assuming that a channel through
the obstructed area can be maintained.
1T is certain that the troubles are
due to the. failure of underlying strata
because these we're unable to bear the
weight that the banks brought upon
them. Under the circumstances 1t is
difficult to understand the impression
that has gained credence in some quar-
ters that sea-level canal would have
avoided the difficulties encountered.
since the cutting would have been
through the same material. but at least
eighty feet deeper.
1T is also certain that nothing can
stop the movement now in progress
until the angle of repose is reached for
the materials under the conditions
that exist, and that this can be
reached only by removing the excess
amount of material If experience
counts for aught. then that gained in
the handling of the slides and the
breaks that have occurred along the
line of the canal leaves no doubt that
the means adopted and now in use Will
effect cure in the slides that now
close the canal; furthermore. that
when cured no further troubles need
be Anticipated from slides in this To-
cality."