The ranch. [volume] (Seattle, Wash.) 1902-1914, 1907-06-15

readers a comprehensive description
of the great Tieton canal project
undertaken by the federal government
for the watering Of very large area of
the finest lands in the far-famed
Yakima valley. Through the courtesy
of the Pacific Builder and Engineer, of
Seattle, we have secured the data given
below, and the illustrations showing
details of the construction have been
very kindly loaned us by the Builder
and Engineer.
The Tieton project has been in con-
temptation by the government for up
wards of three years, but until the fed
eral authorities secured absolute con-
troll of the various private irrigation
works in the Yakima valley nothing
certain could be said as to its ultimate
outcome. Last fall the government
took over by purchase all the private
interests in canal construction in the
valley, and Immediately work was
commenced on the most important or
the new works-the Tieton irrigation
project. Through this project the ir-
rigation of $4,000 acres will be ac-
complished, this body of soil lying
west and north of the city Of North
Yakima. The water supply will be de-
rived from the Tieton river at point
about sixteen miles above the junction
of the Tieton with the Naches river.
The Tieton river drains nearly 800
square miles of mountainous country
on the eastern slope Of the Cascade
mountains. Some of the highest peaks
of the range are included in its water
shed, and it's supply, especially during
the summer, is derived to a large ex-
tent from the melting SHOWS. The
summer flow of the river is, therefore,
generally we'll maintained, and 1t Is
seldom that less than $50 second feet
of water is flowing in it's bed even
during the driest months.
The lower part Of the course of the
Tieton lies in a particularly bold and
rugged gorge or canyon, which IN
some places is more than two miles
across but which in general Is less
than a mile in width. The sides OF this
canyon are frequently precipitous but
always are steep and rugged, the aver
age slope of the sides seldom pelng
less than 60 vertical to 100 horizontal
which any one familiar with engineer
ing methods will appreciate is a par
ticularly steep slope for canal work.
In order to divert the water from the
I1etOn river Onto IH0 lIIiSdOiO ioAAN0
it has been found necessary by the gov
ernment to build a canal along the
southern wall Of the canyon for dis
tance of 12 or 13 miles. By this means
a gravity supply can be delivered at
the highest point of the irrigable lands
which in quality and quantity will be
ample for all purposes of irrigation
within the project. Unfortunately, the
natural obstacles in the way of build
ing a canal in the Tieton canyon are
such that the cost Of the main canal
will be very high in proportion to the
general cost Of the project and as COM
pared with other works where cheap
canals are feasible. The construction
of this canal involves the cutting OF
upwards of three miles of tunnel
through solid rock, and practically all
the rest of the canal work will consist
Of a masonry section.
The plans for the diversion dam are
shown on drawing No. 2, the structure
itself consisting of masonry spillway
founded on rock-flled timber crib work,