TYPICAL ALKALI WATERS 



233 



like that of the upper San Luis Valley, Colorado, the 

 waters of which all contain larger or smaller quantities of 

 sodium carbonate, which permit of rough classification. 

 Irrigation well waters seldom change in composition as 

 do open streams because the water is not subject to the 

 various factors causing fluctuations. 



To show the seasonal fluctuations in the salt content of 

 rivers, analyses of the Salt and Gila Rivers of Arizona (8) 

 are given in Tables XXIII and XXIV. These are excep- 

 tional variations but illustrate how little a single analysis 

 might mean. The Sevier River, Utah, shows a somewhat 

 less fluctuation because not influenced by flood waters. 

 This is shown in Table XXV (33). 



TABLE XXIII. SEASONAL VARIATION IN SALT CONTENT OF SALT RIVER, 

 ARIZONA, EXPRESSED AS PARTS SALT PER MILLION OF WATER 



(a) High and low summer water. Average of four weekly composites 

 of samples taken daily. 



(b) Summer flood water. One weekly composite of daily sample taken. 



(c) High and low summer waters. Average of four weekly composites 

 of daily samples. 



(d) Winter flood water. One composite of daily samples taken. 



(e) Low winter water. Average of ten weekly composites of daily 

 samples. 



(f) Low winter water. Average of thirteen weekly composites of daily 

 samples. 



(g) Very low summer water. Average of eight weekly composites of 

 daily samples. 



