New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1907-01-20
GREAT CARE NEEDED.

An this rreparatory work must be done with
the greatest care. A mistake made at the De-
ginning is likely 20 result later in needless ex-
,end,trre Of money or in great destruction of
rropertv or even in the loss Of life Should a
site for the great Ashokan dam, which IS
"a consist of two huge masonry walls and three
smaller earth dikes. be laid upon some faulty
rock structure or porous gravel bed. the vast
pressure Of the water might some day burst us
barriers and reduplicate the horrors of the
Johnstown flood.
At Ashokan the preliminary work has been
attended with peculiar difficulties. In looking
for the proper site for the dam the engineers
were compelled TO bore from fifty 10 two hun
d-ed feet through the glacial drift which fills
the bottom Of Esopus Valley. As this drift
contains not only gravel but powders Of great
size. the drills have often struck immense rocks
which had 10 be broken by dynamite before tho
rrobes could be sunk deeper The purpose Of
all these borings was 70 find solid rock or i'm
pervious clay which the dam might rest. and
which might be reached with the least amount
OF excavation and consequently at a minimum
cost
And ct the same time that the engineers on
The ground studied the bottom Of the Esopus
Valley their every move was checked off in the
Office OF the chief engineer, J. Waldo Smith, on
the fifteenth floor Of the Barclay Building. on
a series Of maps every preliminary survey and
boring has been noted by means of colored
strings or tacks. and here and there a black
string has been stretched TO Indicate that the
final line is established.
Not only has the site Of every boring been
recorded. but the soil and rock which the drill
has brought TO the surface have been preserved
and labelled like the exhibits of a physician
offered evidence in trial These bortngs
laid IN long, narrow troughs and arranged
exactly in the order that they were before the
intruding drills tore them out Of their ancient
resting place.
abled man to look into the past as well as the
future. These boringB have not only instructed
the engineer what step he should take next but
have revealed 10 the geologist many q chapter
in the history OF the making OF this part Of
the earth. AT AshOkan the survey has shown
that the Esopus, or some ancestor" says van
Norden's Magazine" in recent number. "'for-
merly flowed down 90 the Hudson in a shallow
trough Along came the Glacial Age and filed
this UP with a drift OF earth and powders. When
the Esopus came 20 tts own again II was
crowded of 20 the southern side Of its old bed
against high bank. The soft. even, blue stone
that forms the underlying strata for hundreds
OF feet down all through this region wore away
beneath the stream faster than the powders
and clay, and the Esopus cut for itself new
gorge"
Another task which has taken much Time and
pains Is that OF determining just what part Of
the bottom OF the proposed Ashokan reservoir
should be stripped" Soil that consists OF
decayed vegetation or contains the remains Of
IL. and should be removed. Accordingly, sani-
tary experts have been going all over the great
DaSln which VIII one day hold lake Tor inc
purpose OF getting "dirt samples" They have
been spading uD a bit OF soil here and there,
botning IL carefully. labelling II TO tell Just
whore Il taken from, and then they have
sent the samples down 20 New York City to
the experimental laboratory in Varick street
AZ the laboratory each bottle Of dirt is analysed
with as much 81 Il gold that
had been taken 20 an assayer. Yet for far
different purpose The analist Of Asho1an dirt
IS looking for bad, not good He wants 20
learn how much organic matter IL contains.
which win become breeding place for bacteria
when soaked with water.
Ofher studies OF the effect OF water upon va
rious kinds Of son in the Ashokan Basin are
being made on the spot Tanks have been
erected Rne filled with layers OF earth and water.
ana the action OF one upon the other has been
studied az regular intervals