THE GREAT SHOSHONE DAM.

THE GREAT SHOSHONE DAM.

According to an exchange, temporary works for the great Shoshone dam in Wyoming were completed, so far as possible, early in June, 1906. and were then handling the annual flood. A tunnel. 500 ft. long, had been driven through the rock ledge along the dam site, and a temporary dam has been completed across the dam, 1,000 ft. above the tunnel. A flume conducts water from this temporary dam to the tunnel. The contractors are also damming the permanent soillwav tunnel, which is located 240 ft. above the bed of the stream, has a cross-section of 20 ft. square and will have a discharge capacity of 20,000 cu. ft. per sec., ample provision being thus made for handling the greatest flood the river can produce. The water impounded behind the Shoshone dam will he first conducted sixteen miles down the main channel of the river and then diverted by means of a tunnel, three and one-half miles long, out upon the land to be irrigated. This tunnel is to ft. square in crosssections and will have a capacity of 2.000 acre feet of water every 24 hours. Construction work is being rapidly pushed. About 400 men were at work in the early part of June, the nature of the material encountered being exceptionally favorable for rapid excavation. The soft sandstone can easily be drilled by the use of coal boring augers. These are driven by compressed air. Frequently a hole 6 ft. in depth is driven in six minutes.

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