Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1916-04-20
n, DIAN NOW BEFORE CON-
GsEss WOULD UTILlzE In RIVER .
up' VAST POWER.
|7lNE NITROGEN FROM AIR
n.r Tunnel Would Divert Flow of Sal
40 mon With Drop of 300 Feet
Into Snake River.

oonota Wednesday relative to the pro-
nosod huge electric air nitrogen
plaut for the manufacture of powder
s time of war and fertilizer in time
of neace disclosed that what is known
az tbe Salmon river diversion project
I being considered. Senator Walsh of
{Montana in the debate referred to the
Idaho project as of the type desirable.
This is the project referred to by State
Engineer Lewis of Oregon in a recent
report dealing with Snake river water
mower and Mr. Lewis last year had sug
4oested the adaptability of this site to
the use now discussed. This develop
ment give additional interest to this
great power scheme which would plunge
tbe entire flow of the Salmon river
Into the Snake river at drop of over
$500 feet.
complete profiles and exhaustive data
as to the project, saying:
The project contemplates the con-
struction of dam in Salmon river $50
fleet in height The water will be con-
kducted through the mountain to Snake
N river by means of a seven mile tunnel
with short canals at either end. These
canals will aggregate two and one-half
miles in length.
The low water elevation of Salmon
river at the diversion site is 427 feet
n above that Of Snake river at the power
4 site With a 150-foot diversion dam
the gross head is 577 feet. 1t is plan
ned to allow Al feet for loss of head
\ in the canal and tunnel. sections.
Floods in Snake river will for a short
period reduce the head still farther.
Fur such time further reduction of
\ % feet has been allowed The mini
mum head between the forebay and
tailrace is thus 511 feet. With a loss
of six feet in tn epenstocks the net
minimum available head for the tur-
blnes will be sos feet and the maximum
. $50 feet.
The natural flow of Salmon river will,
with the exception of very short periods
during extremely cold spells, be suffi-
Gent for the continuous development
OF zOO,OO0 electrical horse power. This
plan does not contemplate storage to
SUPPLEMENT- the low water flow.
II is assumed for this estimate that
loO-foot concrete diversion dam will
De constructed in the narrow gorge
ABOVE Freedom on Salmon river. The
assumed depth to bedrock was taken as
ABOUT 40 feet below low water. The
temporary diversion of Salmon river
would be very much Tess expensive than
'lhat OF Snake river. No design was
made for this dam and the estimate of
s1,oVo,O00 is therefore only an approx
mate one, but it is believed to be
reasonably conservative. A base unit
pflee OF $s per cubic yard was used for
,s.timatng concrete in mass for this
diversion
-. Inc estimate of cost for the canal at
eitner end of the proposed tunnel is
ossed upon concrete-lined section of
foo square feet of water area. 1t was
assumed that the average thickness of
eonerete lining would be about 10 inch
=, requiring two cubic yards of CON
.n,. sas.e hning per linear foot at $40 per
eupie yard, and that the excavation
.os1 would be about equal to that of
euoic yards of rock per linear foot
slZO per cubic yard. The total cost
per mile of canal was therefore. taken
os iound sonn numbers as $360,000 per mile,
miles, WV On" oiio nal
a.. net tunnel section of 400 square
aee.. the equivalent of 2O-foot square
suoh, s, Is required for this plan. An
.erage thickness of l8 inches for
uonefete Inning will require little more
foo. .han four cubic yards per linear
wv ana ~ cubic yards of excavation
pp;. pu; ilhear foot will be required. A
onle pilee of about $40 per linear foot
tbo @1vo'ooO per mile, has been taken for
nar r aal. Tunnel. This allows price of SO
n. n, suoie yard of excavation and $3.50
asan s euofe yard for concrete, with the
Tr'unied T. average thickness of Is inches
an.a auultion to the unit price an allow
49,. 49, OF 100000 has been made for
soiaa. sigehcles and for investigation and
i ! 'ioh OF the tunnel location. Since
tbe .possible to change the location of
la.n..uh .uhneA to a great extent without
alss increasing its length, and since
ahlo 'ae conditions appear to be favor.
geoloor ior comparative freedom from
watos sical faults and excessive ground
sibIo II Is believed that it will be pos
cos. 70 so locate the tunnel that the
is ho,:h .lh not exceed this estimate. II
ma, IN that great part of the tun
not WI WI oe IN sufficiently good rock tt
port neeo os either timbering or the sup
hscalG;nn the concrete lining to prevent
for Ilg and that the concrete lining
can h,drge portion of the tunnel length
sin ~. reduced to a thickness which
A nov.. u. exceed an average of 12 inches
ever Or.aon ra OF the tunnel may, how
require a thickness of concret,