The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1889-06-16

by the present owners of the lake, the
South Fork Fishing club, company of
Pittsburg millionaires. Although the dam
originally cost 3lSS, 900, yet the entire out
! lay made by these gentlemen, to replace
the most important portion o. the dam, was
only SIT ,000.
1t is the old story of a common earth
dam, placed there to save the expense of
employing a competent engineer and of
| building properly. 1t happened that the
earth contained much clay, and to this fact
is due the standing of the dam for so long.
1t is the old story, as | said before, which
has been illustrated in Utah by the Manti
dam, the Spring City dam, the City creek
dam, two at Logan and one or two dams on
the Sewer. 1t takes a carpenter or a
bricklayer to build a house, but such i'm
portant work as designing and building a
! dam, why, anyone can do that. Not only
in Utah have earth dams burst, but in
other portions of the United States and in
| England have these carelesSly constructed
dams given way. An earth dam gradually
soaks full of water, and when one drop gets
through that dam is doomed. But there is
no need of building dam so that it will
give way, under any circumstances. Be
cause contractors have built high buildings
that have fallen, or because there is
bridge accident in the United States every
week, on an average, no one would say
that neither high buildings nor bridges
should be built.
But what the general public has a right
to say is that buildings, bridges and reser-
voir dams shall be so built as to be safe,
and they are not safe unless designed, in
every point, in accord with right engineer
ing principles. A few days agoI examined,
at request of the company intending to
build, dam site in southern Utah, which
will hold back about two-thirds as much
water as did the lake at Johnstown-per-
haps 1000, 100000 gallons. The secretary
of the company asked me if simple earth
dam would not hold it! l said: Eyes;
two chances out of three it will hold. Do
you wish to take the chanceS!"
There is nc reason in building such death
traps. There is seldom a reservoir site in
Utah, as far as | have examined, but what
has, near the site of the dam, materials
that, properly arranged, milled or built
would cheaply construct a perfectly safe
dam
In designing dam, 1 always look over
the surrounding country very carefully
to see what have of which can construct
perfectly safe dam and yet without un-
necessary expense. After obtaining and
testing these materials, and noticing what
combinations they will make, l so design a
dam that there are never less than two
ClCloSGo VI LldICIl Id 81 ploGNNl, UlloG IL COu1u
truthfully be said that had either one been
left out the rest of the dam would be con-
sidered safe. But with these two mater
ials both placed, there is no danger. Poor
workmanship, at some point, is the great
danger in dams, for one place that the
water can get through will certainly ruin
the entire dam. By placing these two
classes of material both in the dam. should
one at any point be built carelessly, there
iS on oHa +bof q Of otor,
ial should be carelessly built also at the
same identical point in the dam so that
water could penetrate both materials.
A reservoir dam demands these condi-
tons:
THAT no water can penetrate below
or at the sides of the dam.
2-That there shall be some class of ma
terial of proper thickness that is absolutely
impervious to water.
3-That the dam, as whole, has proper
weight to Withstand the pressure of the
water, and has proper proportions in the
disposition of materials.
IThat the escape pipes are safely
placed.
5-That sufficient spill may be given for
the heaviest storms.
6-These considerations demand most
careful design and as careful workmanship
in building. Dams thus built are the SAT
est Of engineering structures, and no one
living below them need worry the least.
The difference in cost between a simple
elrth dam and one built on proper princi-
pies, using the best materials at hand in
the best possible way is seldom very great,
for usually the major portion of the dam is
earth anyhow. Simple earth dams should
be prohibited by law. 1t is in the careful
study of the materials at hand that safety,
combined with cheapness, consists. No
dam designed for one site is either safe or
cheap for another site Each place de
mands a separate design. Then let US
build reservoirs in Utah to store the two
thirds of our water that now runs to waste.
But let no more simple earth dams be
built that may repeat in any measure the
awful catastrophe.
M F. STURGEs, C. E.