Salton Sea

a temporary body of water in southern California. Ages ago the Gulf of California extended 150 miles farther northwestward than it does now. The Colorado River, busy carving the Grand Canon, deposited its fine silt on the east side of this arm and built a delta out into the gulf so far that it finally constructed a dam clear across and cut off the upper end of the gulf entirely. The waters of the Colorado found their way southward, leaving the northern or upper end to dry out. The climate being hot and nearly rainless, the water evaporated, leaving a depression called Salton Sink. The dry bottom of the old gulf is 285 feet below the level of the sea and consequently more than that below the current of the Colorado River. This explanation of the origin of the Sink is the more credible when we learn that the Colorado still carries enough silt to cover fifty-three square miles of land a foot deep with alluvial soil yearly. The Colorado is subject to a thirty foot rise when the snows melt in the mountains. Ever since the region has been known, the river has had times of discharging surplus water by a couple of old dry channels, the New and the Alamo, into Salton Sink, creating a swamp that soon dried out again.

In 1891 a project was formed to draw water from the Colorado River and irrigate at least a portion of the Sink. The land proved so productive that settlers moved in, towns were built, and two new canals were cut, leading from the Colorado. The soil is so fine and so easily washed out that in 1905 one of the canals began to scour rapidly, and the entire Colorado turned down the northern side of its old delta into Salton Sink.

The entire Sink is so large and so deep that it is believed the river would require fifty years to fill it. Indeed, it is doubtful whether the enormous supply of water would in the end more than balance the great loss by evaporation, but the property interests of the Sink were too valuable to permit trying the interesting experiment. If the Sink were to fill, 150 miles of railroad tracks, 400 square miles of irrigated lands, with their orchards and fields of alfalfa, and the homes of 20,000 people would be submerged or rendered useless. Taking into consideration 700,000 acres of rich land awaiting irrigation, it is not too much to say that the Colorado threatened to destroy $400,000,000 worth of property. There was hurried and desperate work. Dams were built, but high water undermined and carried them away. In 1906 the Southern Pacific Railway and the United States engineers tackled the problem systematically. A spur railway was built across the new channel. Long piles were driven across the stream. There being no foundation but silt that melts away almost like sugar, brush mats 100 feet long were pinned to the bottom of the channel with piling. An army of workmen was assembled. Trainloads of dump cars loaded with stone from several miles away were run out on the trestle to drop their contents in the stream. For months train followed train. Every now and then the waters got under or around the growing dam and washed out sections of it; but gradually skill prevailed. The sullen waters began to rise on the upper side of the dam. The dam held. The Colorado returned gradually to the old course to the Gulf of California, and in February, 1907, the engineers were able to announce that the Salton people were safe.

The streams running northward from the Colorado into the Sink cut the dry valleys into deep gorges that ruined irrigation projects and left the settlers high and dry in torrid heat without water for their farms and orchards. Many homes were washed away; thousands of people lost their all. In the meantime, the swamp at the bottom of the Sink had been enlarged into a sea or inland lake forty-five miles long, fifteen miles wide, and eighty feet deep. A season of unusual rainfall ensued, due, it was claimed by some, to the influence of the new body of water. Mr. Henry of the United States Weather Bureau has pointed out, however, that the sea contains about 2.2 cubic miles of water, enough to cover the area in question with somewhat over an inch of water, a very ordinary shower, while rainfall for the year under discussion amounted to the very unusual depth for that region of over twenty-six inches.

The United States Weather Bureau has taken steps to study the effect of evaporation. Theoretically, the sea should sink about eight feet a year, but for the first few years it dried up less rapidly than expected, the annual fall being about five feet. Mr. D. T. McDougall of the Carnegie Institute is engaged in studying the manner in which the peculiar flora of that region follows the receding waters toward the center of the Sink. All in all, the Grand Canon, the Colorado River, the creation of the delta, the recession of the gulf, the drying out of Salton Sink, the irrigation projects, and the making of Salton sea form an intensely interesting chapter in geography.