The Blackfoot optimist. [volume] (Blackfoot, Idaho) 1907-1918, 1915-08-12

The law permits the ladders to be con-
structed at as great an angle as one
foot in one. But in constructing this
one the angle is only foot in three.
The dam lies nearly north and south
with the southern end almost against
mountain. A short dyke is necessary
here on which work was in progress at
the time of our visit, with 4-horse Fres
noes. From the northern end Of the
dam extends the north dyke, 1880 feet
long. This dyke will be raised to the
level of the dam or seventeen feet.
From the north end of the dam there
has been extended into the dyke con-
crete core reinforced with steel, $50
feet. This core is nine inches thick,
at the top, and increases an inch in
every two feet downward. At the juno
tion of the dam and dyke there is now
being built the blanket or immense en-
bankment Of earth and rock, joining
the two, which will be 400 feet through
the base.
Sheet piling has been driven in the
dyke throughout the entire length. This
piling is driven the same distance into
the earth that the head Of water will
be above, but in no case less than ten
feet. The dyke will have a twenty-foot
crown; a 8 to l up stream slope, and
2 to down stream slope, and q maxi
mum width at the base of 200 feet. The
maximum height will be forty-nine feet
and it viii contain 275,ooo cubic yards
of material. The completed dyke will
also envelop the old dyke. 1t is being
built by the hydraulic fill process. That
is, a powerful hydraulic dredge is used
by which the material is taken from the
bed Of the reservoir and forced through
pipes to the point desired in the dyke.
The dredging equipment consists of
the boat, 3Ox66 feet on which the plant
lis carried. The plant is steam and con-
sists Of six 5O-horse power boilers, one
1850 horse power compound engine, and
one 12-inch dredging pump. In addi-
ton there is 15-horse power engine
(which operates the cutting bar, and q
|20-horse power hoist controls the move
ments Of the dredge. The fuel used il
wood, cut and boated to the point used
by the reclamation service. Each Of the
six boilers weigh 14,7OO pounds, and
were hauled intact on sleds and wagons
over the Teton pass route from the rail.
road, fifty miles distant from this
route.
The dredging is not done nearer than
400 feet of the dyke. This work was
begun at the extreme upper end Of the
dyke at which point a creek comes
into what will be the reservoir. The
boathouse was built on dry ground aAd
the machinery plant installed. Their
"a small temporary dyke was thrown NJ
from the creek was turned from it,
course into this small temporary reser
voir the dredge floated. From then OF
it dug it's own pond in which it floats
The pond stands nearly level full o.
water and breast Of earth thirteel
feet deep is cut out and forced throtgl
the pipes with water by the hydrauli,
process and deposited in the dkye 40o(
feet or more away. In this way tn,
water carried with the material eff
fectually puddles it as the dyke i
made.
. The elevation of the lake or reser
voir proper at low water is 1888 feet
At the present high water level it i
> 6,752 feet, and when the new raise i
completed it will be 6,767 feet. TIL
area of the reservoir at low water
1900 acres; at an elevation of 6.73
or present high water level, the are
> is 22,6O0 acres and at $3.50, or complet
. ed, the area covered with water will b
25,5O0 acres.
The present storage capacity of tn
;, reservoir is $50, 400 acre feet and whe
J, completed the storge capacity will b
" 7S9,500 acre feet. Hence the increase
!, storage secured by the work now i
progress will be 4O9,1OO acre feet. c
= this the North Side Tract will have 81,
ty-one eightieths, or practically tire
~ fourths; and the South Side will hay
!" ninteen eightieths or practically on
. fourth. Therefore the storage provide
2 for the North Side Tract will be
round figures 305,oOo acre feet.
Having practically completed the co
crete work the crew of carpenters h,
been recently laid off permantlv. I'll
total force employed on the work at tt
present time is 225 men, but in the pa
maximum of 4SO have been employee
1t is not considered practical to emple
a greater force on the remaining wor
We consider it only fair to the re
lamatios officers in charge of the wol
to call attention to the difficulties
operation which makes progress slo
and tedious. In the first place Il