SALTON SEA AND THE RAINFALL OF THE 

 SOUTHWEST* 



By Alfred J. Henry 

 Professor of Meteorology, U. S. Weather Bureau 



On February ii, 190J, the break in the Colorado River, zvhicli zi'as described 

 by Mr Arthur P. Davis, Assistant Director U. S. Reclamation Service, in the 

 January number of the National Geographic Magazine, ivas dciinitely closed for 

 the second time. A lake 440 square miles in area and 80 feet deep has been left. 



THERE is a growing belief in the 

 extreme Southwest, and possi- 

 bly in other parts of the coun- 

 try, that the creation of Salton Sea is, in 

 large part, responsible for the heavy rains 

 of the last two years, not only in Arizona, 

 but also in the Rocky Mountain states, 

 and thence eastward over the plains. So 

 strong is this belief that some persons 

 have gone so far as to publicly advocate 

 the maintenance of the present Salton 

 Sea, notwithstanding the efforts now 

 being put forth to shut off its supply. 



Like other popular fallacies, the present 

 one doubtless arose from a careless con- 

 sideration of the facts in the case, failure 

 to consider whether the supposed cause 

 was capable of producing the observed 

 result, and finally, a misconception of the 

 physical laws under which moisture in 

 the atmosphere is condensed and precip- 

 itated as rain. 



The facts, so far as they concern the 

 purpose of this article, omitting all gen- 

 eral details which are already familiar to 

 the public, are as follows : 



As early as October, 1904, there was 

 some seepage water in the depression 

 now known as Salton Sea, but no over- 

 flow water. In November, 1904, the De- 

 velopment Company completed a third 

 intake on the Colorado River some miles 

 below the first and second intakes in order 

 to increase the supply of water for irri- 

 gation purposes. Soon thereafter a flood 

 wave in the Colorado River scoured out 

 the third intake so that it admitted more 

 water than was needed. The surplus. 



which at times was very large, naturally 

 sought the lowest part of the depression 

 known as Salton Sink, and in the course 

 of time Salton Sea was formed. It ap- 

 pears, however, that the increase in size 

 of the so-called Salton Sea was gradual, 

 and that it was not until October, 1905, 

 that the total flow of the Colorado River 

 was carried by various channels, mainly 

 the Alamo and New rivers, into Salton 

 Sink. 



The rainfall of October, November, 

 and December, 1904, in southern Califor- 

 nia and Arizona was not out of the ordi- 

 nary, but beginning in January, 1905, 

 and continuing throughout February, 

 March, and April, an extraordinary 

 amount of rain fell over a belt of country 

 stretching from Florida to southern Cali- 

 fornia, and the region of heavy rainfall 

 also extended into eastern Colorado, east- 

 ern Wyoming, western South Dakota, 

 western Nebraska, and western Kansas. 

 With the coming of summer the locus of - 

 heavy rains shifted to the states of Ne- 

 braska, Kansas, SoiUh Dakota, and Okla- 

 homa and Indian territories. September 

 and October were generally dry months, 

 but in November heavy rains fell in 

 Texas, and thence westward to Arizona. 

 December was dry. In 1906 practically 

 the whole of that great region west of the 

 ninety-fifth meridian received more than 

 the normal rainfall, the regions of great- 

 est excess being central and western Kan- 

 sas, central and western Nebraska, all of 

 South Dakota, Wyoming, Colorado, 

 Utah, and central and southern Califor- 



*■ From The Monthly Weather Review. 



