234 



ALKALI WATER FOR IRRIGATION 



TABLE XXIV. SEASONAL VARIATION IN SALT CONTENT OF GILA RIVER, 

 ARIZONA, EXPRESSED AS PARTS SALT PER MILLION OF WATER 



(a) Low winter water. Average of seven weekly composites of samples 

 taken daily. 



(b) Low winter water. Average of five weekly composites of samples 

 taken daily. 



(c) Summer flood water. Average of two weekly composites of daily 

 samples. 



(d) Summer low water. Average of two weekly composites of daily 

 samples. 



(e) Summer flood water. Average of four weekly composites of daily 

 samples. 



(f) Summer low water. Average of five weekly composites of daily 

 samples. 



TABLE XXV. SEASONAL VARIATION IN SALT CONTENT OF SEVIER RIVER, 

 UTAH, EXPRESSED AS PARTS SALT PER MILLION OF WATER 



Factors Modifying Toxic Limits of Salt. Under or- 

 dinary conditions irrigation by the flooding method with 



