The Blackfoot optimist. [volume] (Blackfoot, Idaho) 1907-1918, 1915-08-12
The Jackson Lake Reservoir
Yfen by Committee Of Newspaper Men Who Visited Site

The steel used is from u inch to ~
inches square. None of the concrete
walls Of the dam proper are less than
two feet in thickness, and it is mas
sive structure. A portion Of the old
government dam, which was rather in
significant by comparison with the new
dam, was not put on bedrock, the en-
gineers considering this unnecessary in
view of the amount of storage for which
lit was built. But in the construction
of the new dam it was deemed nee
essary to 90 to bedrock which was done.
The new dam was constructed in front
of the old dam or on the upper res
ervoir side. The maximum depth to
bedrock was thirty feet below the water
surface Of the reservoir. In accomplish
ing this, immense Golfer dams and pump
were used. We were shown splendid
photographs Of this work during the
different stages of its progress by Mr..
Banks.
In this dam there are twenty sluice
or controlling gates eight feet wide,
by six and one-half feet high. These
gates are placed in the dam level with
the river bed, and above them in the
upper portion of the dam are like
number Of spillway gates or waste
gates of the same dimensions, though
which the excess water will be spilled
over concrete apron directly over the
concrete controlling gates. The lower
gates are Of the sliding type and are
Operated by power from a gasoline en-
CINE on track on top Of the dam. The
leaf Of each Of these gates, or the ap-
pliance that stops the hole, weighs 49,
900 pounds, or five tons. Hence, twenty
|of them weigh 100000 pounds or 100
tons. These weights do not include the
Iron frame in which the leaves are set,
and they, also, are massive. These gates
are in place and in use.
The waste gates are of the radical
type and are operated by hand. These
gates are being set at this time and as
the water is not up to the level of
the openings, are not needed now.
From the deepest bedrock on which
the formation Of this structure is placed
to the top Of the structure is seventy
feet, twentyone feet being below the
headgate stills and forty nine feet above
them. The length over all on top is
1929 feet; the maximum width at tire
lbottom is sixty-one feet, and on top a
uniform width of twenty-four feet. 1t
contains 1880 yards Of concrete and
lions upon tons of steel and fills the
natural river bed. -
In the construction Of the dam, botl
a fish-way and log-way are provided
, The log-way is chute through which
the logs that are floated down the lake
to saw mills below the dam may b.
drawn off.
, The fish-way is of a construction and
, type that was tried out and found te
be a success by wooden way in the OLE
dam. A description in detail is diff
cult. Suffice it is to say that thei pr-n
ciple is much the same as the lock prin
ciple of passing ships past rapids. L
is four feet in width and is comprised
of eighteen bathels or compartments
each Axe feet separated by concret'
partitions At the bottom of each com
partment is a passage way for waite
controlled by gates. Beginning at tn
l minimum height or river below the dam
\ each partition is two feet higher thai
l the preceding one, so that from tn
l surface of the water in one filled com
lpartment the elevation to the next i
Il two feet. This is less than the Law
= requires and is practicable, and fist
t will easily jump the two feet. B.
!. making series of eighteen jumps wit
Y lplenty of chance to rest in the pool
Q between, the fish climb the thirtys
: maximum feet from the river below tn
dam to the water Of the reservoir above