The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-12-18

for increased stability Is i'm according to
the new structure more generous d.
mensions. The original design contem-
plated Il Width at the base OF ~ feet
n the old dam as constructed was 90
feet in width. while the new structure
will be l2i feet wide when measured
along the ann OF the river with
an apron OF rs feet in addition over
that portion of the channel where a. Is
possible for an Increase to occur. The
crest line VIII remain at an elevation
Of about IS feet above low wafer. ard
the .spillway as overflow VIII have a
width OF 200 feet. which dimens'o ns are
practically those used in the old struc-
ture.
A word with reference to the old
structure. which i'm spite of is peram-
bullting proclivities and general dilapi-
dated appearance, possesses elements Of
strength and meritor.ous features that
are not very generally understood. will
he Of interest. Beneath the upper end
OF thc crib work above spoken OF lies
the concrete case which extends in one
solid mass from ank to bank. a solid
wall. In fact. four feet I'm width and eN-
tending downward to firm material he
low, at some points a distance OF Is
feet below the crib work. A response
bility hat always hauhts an engineer
I'm dam construction. Il the knowledge
AlFtN ilO lfldAANN y v Nv nay "
in the execution Of his work. IL is ,tIll
possible for the water TO find its way
under or around the portion ne Is build
ing and In some n wreck the ell
tire enterprise.
II thoroughly conscientious he is new
er entirely free from this vague fear
that emains with him as a nightmare
till he sees the water securely standing
at the predicted level above his struct-
ura In ingtigR Ia fine old STRUCTURE
IL may be said rat this critical ttst
was safely passed I'm a very satisfac-
tory manner. The closest inspection IL
has yet been possible to make has fail
ed To- discover any evidence OF water
working It's way under the concrete
case or around the end OF the dam.
and Il is confidently believed by those
who have studied the matter most :hor-
oughly that the case and the lower
members Of the crib work are absolute
ly intact as originally placed.
The top Of the dam moved down
stream a distance OF nearly IA feet 1T
the point OF maximum movement. and
this like an inch upon a mans nose
is enough To appal the s~tanchest
heart. but the bottom and a large pOr-
ton Of the south end do not show any
a~ppreCiatiVe movement. With his
movement. which nearly all occurred
within a very short time after Il began.
the structure came 10 rest anu. as ut-
monstrating hat Il yet possesses a very
large element OF strength, the tact may
be cited that after this movement Ii
took it's burden and for many weeks
during the high water Of the past sea
son actually carried the water level
within from three to five feet Of the
crest line as designed without material
change.
When a large structure OF any klnd
develops an unexpected weakness the
best informed are not able TO say just
what may happen. but IL has been de-
monstTated since that at no time was
either life or property in jeopardy at
any point below the dam. True II is
that the water of the river backed up
for a distance OF about three miles. but
this channel for the entire distance
Is comparatively narrow n above the
old Trask dam. which is situated some
2O0 feet above the new structure. is but
40 feet deep and becomes less rapidly
in going up the river. IL IL were
possible to remove the dam instantly.
yer this quantity OF water would do
much damage. but with this style OF
construction. a timber crib and rock
filling. il is the universal opinion Of