I). T. MacDougal — The Salton Sea. 



239 



Evaporation was the chief factor in determining the rate of 

 variation of the level in the earlier history of the lake, and 

 consequently the surface fell slowest from November to Febru- 

 ary and most rapidly during the midsummer. The extension 

 of the controlled use of water in the southeastern part of the 

 basin known as the Imperial Yalley has been followed by an 

 irregularly increasing amount of wastage escaping into the 

 lake with the result that variations in level are no longer to be 

 directlv correlated with the seasons. Thus no measurable 



Fig. 3. 



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 -280.3 S.P. Datum 



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58 



Fig. 3. Diagrams showing variations in level of Salton sea, and probable 

 amount of inflow, 1905-1912. After H. T. Cory. 



recession occurred in the period of six months from December 

 to June, 1914. The record for the year, however, will show a 

 net loss, but this may be expected to decrease each year until 

 the waste irrigation waters balance the evaporation and other 

 losses, which will probably result in a permanent body of water 

 of an area of nearly three hundred square miles with irregular 

 fluctuations in a level of a foot or two. 



The composition of the water was of course a prime consid- 

 eration in all physical and biological work connected with the 



