New-York tribune., 1903-05-23
THE BOHIO DAM AT PANAMA.

In THE Engineering Magazine" for June cen
eral Henry L. Abbot and George s. MORRISON re-
new a discussion in which they have Oeen ell
gagged for months relative to certain features OF
the proposed canal across the lsthmus OF fah-
anna The most important point at issue is
whether the dam at Bohio should be sixty-three
or eighty-fve feet high. This structure Will
block the Chagres River as to convert con-
siderable section thereof into shallow Iake'
It will serve the double purpose of making
canal out of that portion of the stream ana OF
storing water as reserve for dry seasons lnci-
dentaIIy. too if will determine the height Of the
summit level and will fix the depth to which II
will be necessary 10 carry the cut in the back
bone of the isthmus at Culebra. For reasons
which will be stated presently the commission
and Mr.. Morrison have preferred the greater eie-
walton for the dam. General Abbot like the
Comit6 Technique of the new French company,
has favored the lower one When once the
United States is in a position TO prosecute Lne
work, it will want to do so vigorously and with
ont hesitation. Questions such are here
raised should be settled only after deliberate
study The pending argument, therefore, can
not fail TO prove useful and timely.
With his plea for low dam at Bohio General
Abbot couples an approval Of the scheme for
creating another storage reservoir near the head
Of the Chagres River. This would call for a
dam at AIhajuela, fifteen or twenty miles east
of the point where the stream feeds the canal
proper In support Of the two lake plan 1t is
urged that it would afford a more trustworthy
resource in dry weather than Bohio Lake alone
With a low dam at the foot of the latter, more
over. the area Of the lake, and hence the waste
through evaporation, would be reduced ma
terially-perhaps 20 per cent A formida BILE
afr1st ivy;d
of nearly ninety feet between only two locks,
such as it is proposed to introduce beside the
Bohio dam, in order to get down to the level
of the Caribbean Sea; whereas two locks having
a lift of only thirty thrty-f1ve feet each
would not prove startling innovations. What
seems to be General Abbots gravest objection,
however is the fear of seepage through the
gravel under the dam. OF course, this would be
proportional mainly to the head" Of the water.
There would be q more serious loss with the
pressure of ninety feet than with that of only
sixty-fve. Mr.. Mor:son has recommended a GER
tain modification of the commissions programme
which might obviate that trouble Instead of
letting the canal finish its route TO the Carib-
bean from the foot of the BOhio dam at sea
level he would interpose an additional lock on
that section and raise the level just below the
dam twenty-six feet. The pressure would be
reduced accordingly. but General Abbot is not
convinced that the change would preclude
dangerous waste of water
In his latest paper on this matter Mr.. Mori-
son lays the chief stress on the fact that a high
dam would promote the convenience of shipping
on the Bohio Lake section of the canal. At
best, he says, the channel will not be any too
wide. This plea partially or wholly offsets the
suggestion that increased evaporation would re-
suit In like manner one might suspect that the
lessened amount of expensive excavation in the
Culebra cut necessary for high summit level
would compensate or more than compensate,
for the increased cost of building a higher dam
at Bohio Mr.. Morrison evidently believes that
there would be distinct pecuniary gain in this
respect but as yet General Abbot will not con-
cede the point He wants more data.
On the whole. the dominating question is
likely to be the extent OF danger from seepage.
If the new commission is seriously Influenced
by General Abbot's doubts Il may decide to re-
duce the height of the BobiO DAM even though
such change increase the cost Of the work. 1t
is unnecessary to point out that security and
certainty %~tSr be the first consideration.