Engineering Wonders of the World
Volume III

THE COLORADO RIVER CLOSURE. 119 THE WATERS WASHING AWAY A HOUSE. The side of the house is seen in the act of falling. The scene now became one of great activity. Hundreds of teams, two dredgers, and several steam - shovels got to work. Six hundred feet of the opening were brush fascines, eighteen inches in diameter, held together by strong foundation cables, were dumped against piles driven at intervals. The current found Strenuous Work. mattressed ; a way under the mattress and below the masses of piles and brushwood which reinforced the feet long across the breach, and construct 5 miles of levees (artificial banks) 5 miles down- stream, and 3 J miles up-stream from the wooden to the concrete headgate ; also to deepen the old canal, and make a new cut (Z) from the river to the upper headgate. About 300,000 cubic yards of material were to go into the dam and 400,000 yards into tho levees. For so colossal a task great prepara- tions were necessary. The The Fifth • , , , c ,, .. , . intense heat of the climate Attempt. made it difficult to obtain sufficient labour until Indians had been re- cruited from far and near and accommodated in a comfortable camp at the dam site. To handle materials and supplies a spur track was built from the Southern Pacific main line at a point 10 miles west of Yuma. This spur was 11 miles long, including sidings. Quarries were opened, clay and gravel pits developed, and preparations made for weaving huge mat- tresses to aid in the closure. In the course of a few months 1,100 piles, 2,000 bundles of wil- lows, 40 miles of steel cable, and 70,000 tons of rock had been collected for incorporation into the dam. Meanwhile the engineers shifted 40 miles of the Southern Pacific track to escape the waters of the encroaching Salton Sink. Four times were the rails moved for this reason during the closure operations. ends of the mattress. A trestle for railway tracks was accordingly constructed along the centre line of the pro- posed dam, and car loads of rock and gravel were dumped until the water was penned and diverted Another , . Disaster, through tho wooden neadgate. However, the Colorado made another effort for freedom, rose, and brought down large quantities of driftwood which blocked the gate. This caused the undermining of the gate, and despite attempts to weight it down with rocks, the water suddenly tore away some 120 feet of the structure and swept it down-stream. The scouring created a channel —fitly called the New River—through the Imperial Valley. Fields of grain and vege- tables, orchards and fruit gardens, entire farms, also hundreds of houses, were swept away by the invading torrent. This disaster closed chapter five. The engineers took counsel together, and quickly evolved a fresh plan of campaign. This was to throw three parallel lines of trestles, each to carry a railway track, across the breach, and dump , , ’ . , ? Attempt. the largest stones obtainable across the by-pass breach, and turn the water through an opening made in the dam. The Southern Pacific Railway authorities made a