The Memphis appeal. [volume] (Memphis, Tenn.) 1886-1890, 1889-06-08
THE DAM INvEsTIGATION.
It Was n Mere Shell, and Constructed In
the Crudest Fashion.

inc eruuest f0sutOn.
JoHysTowN, Pa, June MIR. A. NJ.
Wellington, with Il. p. Burt, Associate
Editor OF the Engineering Necs, OF New
York, have just completed an examina-
ton Of the dam which caused the great
disaster here. Mr.. Wellington states that
tine dam was in every respect OF very in
ferior construction, and OF a kind wholly
unwarranted by good engineering prac-
tees OF thirty years ago. Both the original
and reconstruction was OF earth without
heart wall, but only rip-rapped on the
slopes. The original dam, however, was
made in rammed and watered layers,
which still show distinctly in the wrecked
dam. The new was to all appearance
simply dumped in like an ordinary rail-
road ill, or II rammed, shows no evidence
OF good effect from it. Much OF the old
part is standing intact, while adjacent
parts OF the new work are wholly carried
off. There was no central wall OF puddle
or masonry either in the new or old
dam. 1t has been the invariable pratlce
OF engineers for thirty or forty years
to use one or the other in building high
dams Of earth. 1t is doubtful II there is a
single other dam or reservoir in any other
part Of the United States OF over fifty feet
high which lacks this central wall. The
reconstructed dam also bears the mark OF
great Ignorance or carelessness in having
been made nearly two feet lower in the
81 Nal
have crowned in the middle, which would
have concentrated the overflow il il should
occur at the ends instead OF in the center.
Had the break begun at the ends. the cut
Of the water would have been so gradual
that little or no harm might have resulted.
Had the dam been at once cut at the ends,
when the water began running over the
center, the sudden break Of the dam would
at least. have been greatly diminished,
possibly prolonged so that little harm
would have resulted. The crest OF the
old dam had not been raised in the recon-
struction in 1881. The old overflow chan
mel through The rock still remains, but
owing TO the sag OF the crest in the middle
OF the dam only five and half feet OF
water in IL, instead oil seven feet, was nee
essary 10 run water over the crest. And
the rock spillway narrow at best, had
been further contracted by close grating
TO prevent the escape OF fish, sipped
by good sized timber, and in
some slight degree also by tresile wood
bridge. The original discharge pipes at
the loot OF the dam had becn permanently
closed when reconstructed, and this.
while a minor matter compared TO the
others mentioned, further reduced the
possible rate OF maximum discharge. Tho
net effect OF all these differences OF coudi-
ton was that the dam a. it stood was not
much safer against excessive floods, apart
from its inferior construction, that the
original dam would have been with n crest
only three and a half 10 four feet high
above bottom OF the rock spillway, instead
OF seven feet. IL Is impossible 10 say r.
the rip-rapping OF the new part OF the dam
was as good as the old or not since IL has
been wholly carrirl away. A large
amount OF the old fip.rapping and slope
wall still remains intact and Is OF excellent
quality. Ii does not appear that there
was any great amount OF leakage through
the dam before il broke. Destruction
came from water flowing over the top.
Mr.. Wellington said that no engineer OF
known and good standing for such work
could possibly have been engaged on II
since in the particulars mentioned II vio-
lated the most elementary and universally
understood requirements OF good practice.
lie did not believe that any other dam Of
equal hight had ever been constructed In
this country wholly Of earth, without some
kind Of special protection against leakage
or abrasion by water in the center Of the
dam.
The estimate Of the original dam shows
that IL WIS made OF half earth and half
rock, but II 80 there was little evidence OF
IL In the broken dam. The rip-rapping
was merely skin on each face, with more
or less loose spauls mixed with the earth.
The dam was sevcniy-two feet above water,
ono aud half 10 one outside slope, twenty
feet wide on top. The rock throughout
was about one foot below the surface. The
earth was pretty good material for such a
dam. II Il was 10 be built at all. being OF a
clayey nature, making good puddle. Tho
fact Of is standing intact since 1881 must
be ascribcd, as no engineer OF standing
would have ever tried 10 40 construct Il.
The fact that the dam was a reconstructed
one after over twenty years abandonment
made Il especially hard on the older part
OF the dam TO withstand the pressure Of
| tie water.
Mr. Wellington left for Pittsburg this
evening.