The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1915-09-16
LOGS TO Be CONVEYED
OVER ARROWROCK DAM
MILLIONS OF FEET OF TIMBER
TO BE HANDLED BY AN IN
GENIoUS DEVICE.

Above Arrowrock dam in the basin
of the Boise river it is estimated that
there is 5000, 600, 900 feet of merchant
able timber. Sawed into lumber worth
say, $12 a thousand, this would repre-
sent a value of $S6, 900, 900. 1t is own
ed by the United States government,
the Boise Payette Lumber company
and a number of others with smaller
holdings.
This timber Is to be cut In the inn
mediate future, driven down the Boise
river and converted into lumber at the
mills IA miles below the Arrowrock
dam and just outside the city of Boise.
Here at the big dam, then, is pre-
sented a knotty little problem-to lift
these logs from the reservoir, carry
them over the crest 260 feet above the
bed of the river. and deliver them in
good condition In the stream below.
Take SO Years.
Nothing would be permitted, of
course, to interfere with the main OBJ
Va IN y NtC AAAROhhAbAll5 Va
the 244,O0O acre-feet of water de-
manded for the irrigation of 100000
acres of rich soil in the Boise valley.
But as the dam backs the water for
a distance of IS miles, converting the
river channel into a reservoir, and in
GLIDING both branches OF the stream.
It provides ideal means for the driv-
ing of logs. 1t was early agreed that
some scheme must be devised for lift
ing them over the dam.
Under the direct supervision of En-
gineer Charles H. Paul his assistant.
Walter r. Young, designed as equip
ment based on principals used where
scientific logging is done. This has a
maximum capacity of go, 900, 900 feet
for the period of so days in summer
when the water In the reservoir Is
within As feet or less of the top of he
dam. At this rate 1t Is estimated that
1t will take so years to lift over the
entire 5000, 600, 900 feet.
How Logs viii Be Handled.
BY this equipment located at the
extreme southern end Of the dam logs
of any size or length will be taken out
of the reservoir by e Of a cable
lift and deposited on the concrete deck
on the top of the dam. From this
deck they will be fed by a stop and
loader to power driven spiked rolls
one at a time, the speed under the
control of the operator. These rolls
will carry the logs across the dam
and turn them over to a bull chain
with spurs or teeth to prevent sliding.
The chain will take them down a 62
per cent slope at a speed Of IS feet q
minute and discharge them into a
gravity chute through which they VIII
slide into the river below.
AS this structure must Withstand
the elements for many years 1t is built
of the best Of concrete and steel. 1t
is unique in government construction
Power for its operation is now devel-
oped by the government at the diver
sion dam IL miles below. Later a
power plant is to be established at
Arrowrock Immediately under the
dam.
This dam, the highest in the world,
1885 feet from the bottom of the
to the crest, Is to be dedi-
with a barbecue and harvest
in Boise October 4. 1t Is finish
more than a year in advance of the
time specified at the beginning and at
a cost of $4,000, 900 less than the esti-
BY storing water this season.
the driest in history, 1t saved the
on 100000 acres and practically
paid for Itself.