The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1910-09-16

what is below il. and the only Inference
| tnat could safely be drawn from such
souhdlnSS would be that the drill struck
| something hard-which might be q boul-
der. OF might he a hard plug OF material
lormed by the churnlng of the drill and
| so compncted as to be impenctrable or
hard stratum OF unknown depth which
the drill could not penetrate. Such sound
| !nss are Of little value in determining
the nature of the material on which the
dam is 20 rest.
on the other hand evidence collected
J py Mr. Lippincott. and corroborated in
a general way by letter from Mr. El-
lott. a civil engineer of Salt Lake CITY.
shows conclusivcly that no continuous
lnpe ermeaole stratum exists at the depth
stated. stated and thai dug pits and driven
stratum at much greater depth and
penetrated bodies OF quicksand which
flowed so rapidly into the pipes that the
rea ching bed rock.
II is stated by the engineers of the
company lha, the. sheet plling for abou,
thirty linear feet Is driven 10 depth o,
thlrty-Lwo feet and the remainder only
10 depth of eighteen feet or less. the
statement being that it was driven to
reiusaL he sheet piliDg used was
entirely too light for driving In gravel,
pelhS only SIX inches wide and one-quar-
ter inch thick, weighing about eleven
pounds per linear foot, and moreover.
1t was driven with a hammer weighing
only 100 pounds For driving through
gravel and boulders, such as found IN
one half Inch thick and weighing not less
1nan forty pounds per linear foot, and
5000 pound hammer should have been
used II this had been done the depth
Qf refusal would have been very DIFF
ferent Nothing is said in the specih-
cations about the size Of The piing or the
sion.
II is well known to construction engl-
neers that IT Is difficult matter TO
and naturally. the fewer joints the bet
ter for the impermeabili,y OF the cur
tain formed with the piling A larger
sented fewer seams through which leak
age could have taken place AS now
driycn, water Is probably passing through
be an impermeablc curtain driven TO an
bedrock.
the gravel cone of Cedar creek, into
which the water from Cedar creek at all
times except In food, has been sinking
for ages The dam is composed OF pre-
1t may we'll be asked. why, il The
waters wat Of Cedar creek have been sinking
for centuries, will not the waters OF Los.
river, when piled up under head, do the
same thing The only known answer
vented by proper means" To facilitate
the entrance of the water into this gravel
bed. great borrow pits. exposing large
areas Of clean gravel. have been cxca-
waited in the reservoir site near the dam.
In places the water, when at its maxi
mum level. would he fifty feet deep over
safe to assert that the water Is going TO
pass freely under the dam and cutoff
trench. shown on the plans and men
toned in the specifications.
We have no hesitation in saying that
such foundation for dam to impound
water to a maximum depth of 10 feet
is insufficient and insecure.
DAM AS CONSTRUCTED.
In section .. division l OF the specn-
cations the dam is defined as an earth
dam, and in division OF the same sec
ton, zone OF the definitions OF earth is
"a mixture OF earth and gravel contain
ing over 10 per cent of earth" and TINS
Is what the entire dam, as now con-
structed, is composed of II is too late
specifications really meant by those def
nitions. because. there being no other
definitions In. the specifications OF the
material to be used in the dan dam the
built the dam OF this material. which
might be said to be d mixture OF earth
and gravel containing over 10 per cent of
earth.
Here is a grave defect In the specif
cations. and, "to make bad worse" the
method of depositing the material is
lowing him to dump the gravel from high
trcstles. thus grading it from fine 10
coarse in vertical direction downward.
II this material could have been graded
from fine TO coarse in a horizontal d.
rection down stream and placed in the
dam in q skillful manner an impcrmcable
terlal: but, to specify that it should be
dumped from trcstlcs on the lower and
upper toe Of the dam was merely 10 make
a series Of blind drains through the dam
as water passes freely through the dam
(althoush the reservoir is almost empty)
and there is practically no pressure upon
the dam. IL may well be. asked what
would happen to this dam il the reser-
voir above it could be filled with water
10 depth of 110 feet, exertinE pressure
There is no provision In the specif-
cations for making the dam tight, but
great reliance seemed to have been
placed on saturating portion OF The
same material used for the body Of the
dam. and thus creating so-called .'pud-
died material in the center of the
DAM
There Is no definition OF puddle, or
pudding material in these speCihca-
tlons-a fatal omission. II Is vaguely
alluded to as the material N ,ho CLAUSE aus,
inference that we. can draw from this
definition is that the material alluded to
is that of which the dam Is composed
The only treatment received by this ma
terial Is the addition OF certain amount
Of water played upon 1t from small
10 say that the result IS not puddle"
1t is a heterogeneous mass of boulders.
gravel OF all sizes, and occasional small
pockets OF fine clay, through which
water could pass freely
LIPPINCoTTs REPORT.
We have been asked TO state in this
report whether we agree or disagree
with the general findings in the report
made by Mr.. ]. b. Lippincott. assistant
chief engineer Of Los Angeles aqueduct.
These findings may be summarized as
follows:
Cd "The tests by sounding rods for
material in the foundation
arc misleading We agree win this
are Of no value for a structure OF the
magnitude and Importance OF the pro-
posed Mackay dam.
CO That "the gravel bed or cone
formed by Cedar creek and on which the
greater portion OF the dam rests Is per
Vious" We agree with this statement
(3) That "the sheet piling has not been
driven TO Arm rock and that the pud
H.,