38 



The National Geographic Magazine 



time used in the control of the waters. 

 The water was diverted from the Alamo 

 channel at a point called Sharp's Head- 

 ing, just below the Mexican line, in the 

 southern edge of the Imperial Valley. 

 The water was led by canals over the 

 land to be irrigated and settlement began. 



The headquarters of the irrigation 

 company were established at a town 

 called Calexico, adjoining the Mexican 

 line, this name being derived by sub- 

 stituting the first syllable of the word 

 "California" for the first letter of "Mex- 

 ico." Settlers gradually came in and, 

 the valley proving to be very fertile, de- 

 velopment proceeded apace. As the de- 

 mand for water became greater, how- 

 ever, the supply became less. The muddy 

 waters of the Colorado River, checked 

 by their entrance into the artificial chan- 

 nel, and still further checked by the ob- 

 struction of the headgate, deposited their 

 load of mud, and constant effort was 

 necessary to keep the heading open. The 

 unsuccessful attempts to maintain the 

 canal heading led to its abandonment and 

 to the cutting of a new one near by in 

 which no headgates were provided. This 

 gave somewhat less trouble, but it, too, 

 gradually began to fill and the effort at 

 maintenance had to be continued. Sev- 

 eral new headings were cut for the same 

 reason, and serious losses occurred in 

 the Imperial Valley from shortage of 

 water during the time when most needed, 

 owing to the difficulty of getting suffi- 

 cient water into the head of the canal. 



After repeated failures of the eft'ort to 

 maintain an open canal heading, the com- 

 pany finally went to a point about four 

 miles below the Mexican line, where a 

 greater declivity from the river bank 

 could be obtained in a shorter distance, 

 and there cut a large channel, with the 

 idea of obtaining a sufficient velocity of 

 water to prevent the deposit of sediment 

 in the canal heading. In this respect the 

 attempt proved successful, and through- 

 out the low-water season of 1904-05, 

 which occurs in winter, a large supply of 

 water was furnished through this chan- 

 nel, sufficient for the irrigation of about 



75,000 acres of land, most of which was 

 imder cultivation in the Imperial Valley. 

 The Southern Pacific Railroad built a 

 branch road from Old Beach through 

 Brawley, Imperial, and Holtville to Ca- 

 lexico, and began building through Mex- 

 ican territory from Calexico to Yuma, 

 intending to make this the main line and 

 cut out some heavy grades now en- 

 countered between Pilot Knob and Yuma. 



THB BREAK Olf JUNE, I905 



The large new heading in Mexico 

 maintained itself without silting through- 

 out the low-water season, but when the 

 annual flood of May arrived the larger 

 volume of water and the consecjuent in- 

 crease in velocity began cutting the chan- 

 nel, and in June it was found that the 

 volume of water running toward the Im- 

 perial Valley was many times that re- 

 quired for irrigation and was rapidly 

 cutting the channel wider and deeper. 

 By the end of August, 1905, the ma- 

 jority of the water of the Colorado River 

 was flowing toward the westward in- 

 stead of the south, and the Salton Sea 

 was rapidly rising and submerging por- 

 tions of the Southern Pacific Railroad 

 track, which were hurriedly moved to 

 higher ground. 



The distance from Yuma to the Gulf 

 of California along the general course 

 of the Colorado River is about 75 miles. 

 The distance to the Salton Sea is not 

 very much greater, but the difference in 

 elevation between the gulf and the Salton 

 Sea is about 280 feet. The gradient 

 from Yuma to the gulf is about two feet 

 per mile along the windings of the river, 

 which is the natural gradient adopted by 

 this river under the circumstances with 

 which it is beset. The channel to the 

 Salton Sea, therefore, had more than 

 200 feet surplus declivity, so that the 

 water in running through that channel 

 was rapidly eroding its bed. It cut the 

 gorge wider and deeper near the Salton 

 Sink and formed great falls or cataracts 

 in the channel. The channels near the 

 vicinity of Calexico had been so nearly 

 obliterated with the lapse of time that 



