THE CAHUILLA BASIN AND DESERT OF THE COLORADO. O 



ally to the Indian name, wrote it "Cohuilla," and sometimes "Cahuilla." This last form 

 seems to have been more generally accepted and is preferred to Cohuilla, Coahuilla, or 

 any other. 



DESICCATION OF LAKE CAHUILLA. 



With our present knowledge of the delta deposits of the Colorado, the varying phases 

 of the stream, the lightness and depth of its deposits of silt, its quicksands, its shifting 

 channels, and uncontrollable ways, it is easy to realize that the inflow to Lake Cahuilla 

 must have been extremely variable and uncertain. We can realize that under favorable 

 conditions the whole volume of the Colorado may have been diverted alternately to the 

 Lake and to the Gulf, and that long intervals of drought accompanied by drying up were 

 often experienced. 



Writing upon the subject in 1853, attention was directed by the writer to the tradi- 

 tions of the Cahuilla Indians, as follows: 



"The explanation of the formation of the lake and its disappearance by evaporation which 

 has been presented, agrees with the traditions of the Indians. Their statement that the waters 

 retired poco-a-poco (little by little) is connected with the gradual subsidence due to evaporation, 

 and the sudden floods of which they speak undoubtedly took place. It is probable that the lake 

 was long subject to great floods produced either by overflows of the river at seasons of freshets, 

 or by a change in its channel, or by a great freshet combined with a very high tide, so that the river 

 became, as it were, dammed up and raised to an unusual height. The present overflows, though 

 comparatively slight, are probably similar; and yet it is possible that the interior of the Desert 

 might be deluged at the present day, provided no elevation of the land has taken place, and the 

 river should remain at a great height for a long time — long enough to cause the excavation of a deep 

 channel for New River." 1 



SALTON SEA. 



This is precisely what has recently happened by the cutting of irrigating canals and 

 by the uncontrolled flow of the Colorado water: deep and destructive channels were cut, 

 a partial flooding of the desert followed, and the "Salton Sea" was formed. The body 

 of water which so recently threatened the restoration of the former lake conditions, by the 

 month of February 1907 had attained a length of 45 miles, a maximum breadth of 17 miles, 

 and a total area of 410 square miles, with a maximum depth of 83 feet. It extended from 

 Imperial Junction nearly to Mecca Station. It submerged railway stations and neces- 

 sitated the removal of the track of the Southern Pacific for 67 miles to a higher and more 

 northern bed. By the great and masterful exertions of the engineers in charge, seconded 

 and supported by the Southern Pacific Railroad, the destroying deluge was stopped in 

 the month of February 1907 and the gradual disappearance of the Salton Sea by evapora- 

 tion commenced and is now in progress. In this we have immediately before us a prac- 

 tical exhibition of what must have happened many times before. 



Evidently in the case of the ancient Lake Cahuilla, with the loss of the supply of water 

 from the Colorado the lake disappeared by evaporation. The conditions for this were 

 extremely favorable. Of the rate of evaporation and the time required for the com- 

 plete desiccation of the valley, we have no direct evidence, but there is every reason to 

 accept the statement of the Indians that the water retired little by little, or very slowly, 

 and no doubt years passed before the lake dried up. 



RATE OF EVAPORATION. 



Experiments by me upon the rate of evaporation in the Tulare Valley, California, 

 in 1853, indicated 0.25 inch per day, or between 7 and 8 feet yearly. 2 Dr. Buist found 



1 Report Geological Reconnoisaance in California, p. 238. 



• Report Geological Reconnoissance in California, p. 195, and Trans. Geog. Society, vol. rx, p. 39, 1849-50. 

 See also, Trans. National Institute, Washington. 



