Engineering Wonders of the World
Volume III

THE COLORADO RIVER CLOSURE. 121 DUMPING EARTH AND STONES TO FORM THE DAM. tremendous effort to carry out the scheme, utilizing every quarry within a radius of 400 miles, and dumping daily 200 car loads of the rock thus obtained. The work began on November 24, 1906. Twenty days later the breach was closed, and the water had been forced into the old bed of the Colorado—all, that is to say, which was not drawn off through the concrete headgate to supply the irrigation needs of the valley. Just when the fighters were beginning to congratulate themselves on having at last subdued the river, it breached the levee below the dam, and soon had eaten out an opening two-thirds of a mile wide. The seventh and last struggle began on January 27, 1907. Three lines of trestles, resting on piles 65 to 90 feet long, were reared across the break, at the cost The Seventh severa| failures and great Attempt. labour. It was actually neces- sary to weight the piles with water tanks placed on top to prevent them being loosened by the water. In all, some 100,000 cubic yards of rock and 75,000 yards of clay and gravel were deposited from the trestles. The dams gradually ponded up the river until, when it had attained a depth of 12 feet, it resought its old channel. The fight was definitely won by the end of February. The month’s work Success 9 clt I had been most severe, calling for the services of nearly 1,300 labourers— including 375 Indians—600 horses, 7 loco- motives, a steamboat, and a fleet of barges, dredgers, and pile drivers. The contest between man and river had lasted three years, and its termination reflects the highest credit on the organization of the Southern Pacific Railroad, which alone could have carried the business through in time to save the Imperial Valley, and also on the engineers in charge of operations—Colonel E. Randolph and Messrs. C. E. Rockwood, H. T. Cory, T. J. Hind, C. K. Clarke, and E. Carrillo. As the dams and levees have withstood some severe floods, it seems unlikely that the river will “ take charge ” again. Even if such a catastrophe should happen, the engineers, taught by experience, should have less diffi- culty than before in forcing the waters back into their natural channel. PART OF THE COLORADO RIVER LEVEES, OR CONTAIN- ING BANKS, WHICH HAD A TOTAL LENGTH OF 8| MILES, AND CONSUMED HALF A MILLION CUBIC YARDS OF MATERIAL.