Daily capital journal. (Salem, Oregon) 1903-1919, 1915-09-25
(Capital Journul Spegial Service.

Capital journal Special Service.)
Boise. Idaho, Sept 25.-lf- the CON
crete in the Arrowrock dam, the high
est in the world located 20 miles above
this city, which will be officially dedi-
Gated October A with appropriate serv-
ices here, were placed in the average
block in most any city in the United
States, il WOULD stand flush with the
four streets around il, as high as 10.
story edifiee; if it were put into col
unm 10 feet square, it would stand 20
miles high. No bigger job Of concrete
mixing for one structure was ever at
tempted before in this country. Today
this dam stands completed, tribute
to the reclamation service and engin-
eering and constructing ability of f.
Il. Weymouth, supervising engineer of
the Idaho district; Charles II. Paul,
construction engineer and James Mum,
superintendent of construction.
IL this masterpiece in concrete could
be weighed il would tip the beam at
over million tons. Today it is wedged
and anchored in arch shape with ra.
dius of curvation at 662 feet, hoo feet
I long btween sheer mountains towering
mile high. Its total height is 34S.5
feet, 81 feet of which is below the
Boise river bed across which it has
been constructed, 1t rests on u base
240 feet wide which represents its
thickness where it is concreted to gran.
lite. At the top it is l6 feet wide,
crested with concrete roadway guard
ed on either side by u parapet wall
four feet high crowning which are are
! light pedostals the entire sweep of the
curve. The sides are also anchored to
granite cliffs. Inside of it are spacious
inspection galleries ,unning its full
length at various levels, the lowest 23O
feet below normal high water surface,
In these galleries is the mechanism that
operates the 20 outlets controlling the
impounded water. 1oday two of these
four feet and four inches in diameter
control the total flow of the river.
There are more steps inside the appar-
entity solid dam than are found in most
hostelries. They, TOD, ure made of
concrete,
One side Of the mighty dam contains
concrete deck over which logs floated
down the reservoir can be snakod across
and>shot into concrete chute, through
tunnel and dropped 90 feet into thI
river below. There are three billior
feet of merchantable timber valued al
thirty.six million dollars tributary Il
this reservoir and it is estimated it vii
take fifty years to float and shoot i
over the dam. On the opposite side II
concrete coated spillway cut out o
solid granite to take care of water il
the flood season. 1t has a capacity o
10000 second feet. The crest is 10l
feet long and the water, rushing owe
1t, drops into trench 10 to 20 fee
I, deep and is carried distance of 0Ol
: feet around the dam cascading down tn
y mountain side into the river below. Fo
I, extreme flood waters the dam Is so bull
\ as to allow flow Of four feet in dept
. to rush over il without damage to tn
structure.
!, Turning constantly, mixing an
u kneading their twoton charge OF cor
: crete, double cone mixers ehurned fO
= four years to mix enough concrete I
fill the excavation for the dam an
raise it to its present towering height
A total of seven hundred thousand cul
:, ic yards of rock aud dirt was cxcavate
t for both dam and spillway and 81
! hundred cubic yards of concrete wer