The Uncomphragre Irrigation Project an Hydraulic Engineering Feat
The work of building the tunnel and a series of canal “drops,” as they are termed, which will divert the Gunnison river, in Colorado, from its course and lead the waters down from the mountains and under control for irrigation purposes is nearly completed. In August President Taft, on his western trip, will touch an electric buttom which will set this remarkable piece of hydraulic engineering in operation.
The river Gunnison is to be led from its ancient channel by being turned into a tunnel 2,000 ft. long which leads directly through the mountain to the point of emergence in the Uncompahgre valley. Down this valley the waters will be further led in a series of canals, “drops” as they are termed, having positions relative to those of locks in an ordinary canal. The water being thus gradually stepped down it looses its torrential aspect and it becomes possible to divert it into many lesser channels and lead it across some ISO,000 acres of rich agricultural land for irrigation.
This tunnel and system of canals is known as the l ncompahgre project, ranking third among the great reclamation enterprises of the government, and is the first to approach completion. It is a highly spectacular piece of ngincering and will rank among the great irrigation systems of the world.
The estimated cost of construction is toward $4,000,000. Enormous difficulties have been met and conquered in making the subterranean channel for the river since the beginning of the work, four years ago.
It was comparatively easy to work at the west side of the tunnel. The slope of the mountain toward the l’ncompahgre valley is gentle, but on the Gunnison side it was neces sary to build a wagon road leading into a diffi cult canyon, where the work at the east portal was started. This road is 16 miles long and in some places rises 23 ft. in every 100 ft. Down this road heavy machinery was hauled and the materials for building a town of workers at the portal. Tremendous flows of water encountered in digging the tunnel added to the dimities. The water going down grade with the slope of the tunnel had to he pumped out at the rate of 500.000 gal. per day. Subterranean lakes were tapped, and, at times, when the drills penetrated the water, a stream of great volume and force would shoot out through the hole, knocking the men away from the air drills, and even knocking the “muckers” off the tram cars. Hot water was encountered at times, raising the temperature of the tunnel to such an extent that the miners were compelled to work almost naked. At one time a heavy flow of carbon dioxide, or choke damp, caused the workers to run for their lives, many narrowly escaping asphyxiation. It was three weeks before it was possible to work again in the headings, and then a ventilating shaft 680 ft. deep had to be sunk. A long stretch of fossil sea shells, loose and crumbling, compelled the use of a special system of timbering, causing another vexatious delay and extra expense.
But the problems have been met and solved and the trying work is over. Only a few rods of shale and rock remain to be blasted, which is likely speedily to be done by the three-shift lorce of miners.
The 12xl0-ft. tunnel is faced with solid concrete, hacked by heavy timbers, which in turn rest against the solid rock. The canals as well are of concrete construction. Through this waterway will flow a body of water 9 ft. deep, with a carrying capacity of 1,300 cu. ft. a second.
The Uncompahgre valley is at present an arid desert, hut when the irrigation water is made available it is expected that it will at cnee become prolific with crops of peaches, melons and potatoes and other produce.