Locating and excavating several of the main canals proved almost
as difficult and trying as the building of the big dams. This was
especially true in the Yakima and Okanogan valleys in Washington,
the St. Mary and Flathead in Montana, Uncompahgre and Grand River in
Colorado, and the Utah valley, Utah. These canals cling to the edges of
deep and precipitous canyons, or hug the steep mountain slopes. Here
and there huge aqueducts of reinforced concrete span the chasms. For
miles the water is siphoned across broad ravines in iron-banded stave
pipe, or flows in tunnels through the cliffs.
The Tieton main canal of the Yakima project, Washington, for a distance
of twelve miles is through a very rough country. It is cement lined
throughout, and for two miles is in tunnels. For the greater part of
its length it hugs the side of the canyon, in places 500 feet above the
river. The lining for the canal was molded on the river bank, where
water, sand, and gravel were available for concrete making, and the
forms were carried to the top of the canyon by tram and cableways.
The capacity of the canal is 300 cubic feet per second, and it is now
irrigating 40,000 acres. The High line Canal of the Strawberry Valley
project swings around the steep slopes of the Spanish Peaks of the
Wasatch Range in Utah for several miles. At one point a portion of the
water is dropped in pipes to the turbines, where power is developed and
distributed to several towns in the valley. At various points along its
course the canal is covered with a reinforced concrete roof to prevent
injury and filling up from avalanches in the spring.
WRITTEN ESPECIALLY FOR THE MENTOR BY C. J. BLANCHARD
ILLUSTRATION FOR THE MENTOR, VOL. 6, No. 17, SERIAL No. 165
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.
[Illustration: GUNNISON TUNNEL. COLORADO]
_RECLAIMING THE DESERT_
_The Gunnison Tunnel_