44 



THE SALTON SEA. 



The diagram on page 197 of the bulletin referred to shows representative variations 

 in the flow of the river at different times of the year; although it is to be remembered that, 

 at the time Salton Sea was formed, the flow of the Colorado was very irregular. From 

 the data there given an estimate was made of the average flow of water in the river for 

 each of the periods during which samples were collected for analysis. The results thus 

 obtained for each of the periods are given in table 13 in parts of a total of 100,000 taken 

 as the yearly discharge of the river. 



By means of these relative values showing the variation in the flow of the river the mean 

 composition of the water discharged by tlie river in a year may be readily calculated from 

 the analyses of Forbes and Skinner by multiplying the values given for each constituent 

 for the difTerent periods by the number representing the flow of water for that period, and 

 dividing by 100,000. The sum of the results for each constituent will represent its concen- 

 tration in parts per 100,000 of the total water discharged by the river in a year. 



Table 13. — Seasonal variation in the flow of the 

 Colorado River. 



Table 14. — Composilion of the salts leached out from the bottom 

 of the Salton Sea as calculated from the excess of the constitu- 

 ents of the lake water in 1907 over that of the water from which 

 the lake was (armed. 



Constituents. 



Na.. 

 K.... 

 Ca... 

 Mg.. 

 SiOi. 

 CI... 

 Br... 

 SO... 

 CO... 



Parts per 100,000. 



Composi- 

 tion of 

 Salton Sea 

 in 1907. 



111.05 



2.30 



9.95 



6.43 



0.93 



169.75 



trace 



47.60 



6. 58 



Calculated 

 mean composi- 

 tion of water 



annually 



discharged by 



Colorado 



River. 



10.36 

 1.38 

 8.78 

 1.70 

 1.97 

 9. 85 



14.18 

 8.31 



Salts taken 



up from 



bottom of 



Salton Sea. 



100.69 

 0.92 

 4.17 

 4.73 



169.90 

 trace 

 33.42 



Since the present water in the Salton Sea came from the Colorado River, then the 

 excess of its constituents when expressed in parts per 100,000 over that calculated for 

 the water discharged in a year by the Colorado River must represent the composition of 

 the salts leached out from the bottom of the lake. In table 14 is given the composition 

 of the salts thus calculated to be leached out from the bottom of the lake previous to 

 June 3, 1907. That the greater part of the salts in the bottom of the lake were taken up 

 before this date is indicated by the yearly analyses made since then, and by the partial 

 analyses of 1911. 



The concentration of the carbonates in the Salton Sea would appear from these analyses 

 to be less than in the Colorado River. The difference, however, is largely due to different 

 methods of analysis. In 1907 the carbonates in the Salton Sea were determined only in the 

 evaporated residue, while the carbonates given for the water of the Colorado River represent 

 the total carbonates in solution expressed as the normal carbonates. As was shown by the 

 analysis of 1911, the carbonates in the residue from the Salton Sea water amounted to 

 only about two-thirds of the carbonates in solution expressed as the normal carbonates. 

 It would appear, therefore, that the concentration of the carbonates in the Salton Sea in 

 1907 differed little from what would be expected to come from the Colorado River, and as 

 the carbonates have not increased since then it follows that little or no leaching of carbon- 

 ates from the bottom of the Salton Sea has taken place. 



If it be assumed that all the salts deposited by the evaporation of the original lake 

 were again taken up by the present lake, then the constituents given in the last column 

 of table 14 must represent the composition of the original lake. 



