236 



D. T. MacDougal—The Salton Sea. 



effect of allowing a large quantity of water to now over its 

 western bank and towards the Fattie Basin, and a large lake 

 has now filled the lower part of this depression. 



During the summer of 1906, and at the time when the maxi- 

 mum inpour w r as reaching the Salton Sink, the channels of the 

 Alamo and the New River began to cut backward from the 

 lower end, and the soluble, loess-like soil along their courses 

 was carried into the lake, leaving the deep precipitous-sided 

 valleys through which the present streams flow. 



Some idea of the magnitude of this displacement and redis- 

 tribution of material may be obtained from a statement made 

 by H. T. Cory,* that the total yardage thus moved is over 



Fig. 1. 



Fig. 1. Northeastern shore of Salton sea, Feb. 1907, with tongues of 

 water extending up the channels of desert washes : hills forming islands 

 in distance. 



450,000,000 cubic yards, or almost twice that of the Panama 

 Canal. 



A good deal of water still passes through both the Alamo 

 and the New River, but this is merely the overflow from the 

 irrigation canals, and it is quite improbable that with the in- 

 terests now at stake in the Imperial Valley and the close watch 

 kept upon the river by the engineers, any further uncontrolled 

 incursion of water will be allowed to take place. 



In the region of the lower Delta, however, conditions are 

 very different ; here we have a large, wayward, and silt-laden 

 river, thrown out of balance by a temporary diversion, and 



* Proceedings of American Society of Civil Engineers, vol. xxxviii, No. 9, 

 p. 1457, 1912. 



