The Caldwell tribune. [volume] (Caldwell, Idaho Territory [Idaho]) 1883-1928, 1916-03-24
RAPID INCREASE IN THE
FLOW OF BOISE RIVER
Arrowrock Reservoir Rises Four Feet
From Monday to Tuesday Morning

The water level in Arrowrock reser-
volr raised four feet between 9 o'clock
Monday morning and 9 o'clock Tues
day morning and is still rising. in
view OF the rapid rise, the Boise pro-
Ject officials decided to hold enough
water in the reservoir to raise the
level above the higher gates and let
the water act as a protection against
frost. Up to date, the effort was to
keep the water below the gates, so
as to avert danger from frost or ice.
At noon on Tuesday two thousand
second feet of water was liberated,
the intention being to- hold the rescr-
yoir below the higher gate level
When it was found that so much
water was coming into the reservoir
that the release of two thousand sec
ond feet would not suffice to hold
down the level, the decision was
reached to let the water come UP
above the gates.
Reservoir Levels.
The bed of the Boise river at Ar
rowrock is 2o56 feet above sea level.
The water surface in the reservoir
was 3l03 feet above sea level at 9
o'lcock Tuesday morning, having
risen from 5000 feet during the pre-
vious "a hours. The center line of
the higher gates is BIOS feet above
sea level, and the present intention
is to raise the water level in the
reservoir to 31l0 feet above sea level
The crest of the Arrowrock dam spill
way is sos feet above sea level.
Increased Flow.
On Monday morning the natural
flow of the Boise river, below More's
creek, was 5000 second feet, which
was increased to 1000 second feet "a
hours later. Out of that, 1860 sec
'ond feet is being diverted into the
main canal for storage in Deer Flat
reservoir. Up to the present the main
canal has been carrying 600 second
feet. Deer Flat reservoir is now ap-
proximately one-third full, containing
about fifty thousand acre feet. Ar
rowrock reservoir also contains about
fifty thousand acre feet, but this
amount will be materially increased
when the water level is raised five
feet above the center of the higher
gates.
Controlling Run-off.
The contour of Arrowrock reservoir
is such that the surface area increases
rapidly with the rise of the surface
level. The intention of the Boise pro-
ject officials is to save as much stor-
age capacity as possible for the big
food run-off which is certain to come
this spring. The natural flow of the
river above Arrowrock at the present
time is about seven thousand second
feet. The greatest amount of water
the river has ever carried past the
city, so far as the records show, was
thirty-two thousand second feet. That
flow, of course, caused damage in
Boise. 1t is to protect the city from
possible damage by flooding that the
reclamation officials are deferring the
storage of water, in order that reser-
voir capacity may be available when
it is needed for protection. There is
no concern about filling the reservoir.
The object is to fill it gradually and
keep the river below down to a safe
level which is being accomplished.
Ice is Rotting.
While the ice on the surface of the
Arrowrock reservoir is thick, it is rot
ting rapidly and strong wind would
probably break it up. To keep the
ice from clogging the gates is the
problem the officials have to deal
with and thus far they have succeed
ed admirably