Engineering Wonders of the World
Volume III

BUILDING TRESTLES ACROSS THE BREACH. THE COLORADO RIVER CLOSURE The Story of a Three Years’ Struggle Great to close a Breach River. in the Banks of a A MONG the many tasks that fall to the Z—X lot of the engineer is that of altering “*■ the flow of a river. Perhaps a stream bursts its banks and changes its course : it must be forced back into its original bed. Or, on the other hand, it may be necessary to divert a river from its natural path for irrigation or other purposes. Such undertakings are usually effected with- out difficulty, by throwing dams across a breach in a broken bank, or by digging a new channel, as circumstances may need. But in the case of the Colorado River outbreak and closure the problem was such as to make its solution a matter of world-wide interest. The Colorado is one of the largest rivers in the United States. It rises in the Rocky Mountains of Utah, and after flowing through the Grand Canyon and tra- The Cölörndö versjng a stretch of flat coun- River. try, empties itself into the Gulf of .California. The flat stretch referred to commences at Yuma. Some hundreds of miles west of this town is a dried-up ocean bed known as the Salton Sink. It lies about 300 feet below sea-level, and was, until re- (1,408) man, except for the great cently, useless to salt deposits found in its deepest depressions. Presently some one discovered that the soil of the basin—detritus deposited by the river during the course of ages—had a natural marvellous fertility when brought into contact with water. In 1896 a scheme was inaugu- rated, under the name of the California Develop- ment Company, to divert part of the waters of the Colorado into the Imperial Valley, an upper bench of the Sink. Nature had pre- pared the way by cutting a channel, filled onh/ at exceptionally high floods, many miles through the valley, from a point about twelve miles below Yuma. It was necessary only to turn water into this canal to lead it practically fifty miles in the requisite direction. In 1900 the Development Company tapped the river several miles above the point at which this dry channel left the Colorado, put in a headgate or sluice some 80 feet long, and dug an ar- An lr"Kat'°n tificial canal parallel to the river from this headgate to the channel. (See Fig. 1.) This last was made the feeder of many smaller irrigating canals and ditches vol. in. 8