234 



ALKALI WATER FOR IRRIGATION 



Table XXIV. Seasonal Variation en Salt Content of Gila River, 

 Arizona, Expressed \s Parts Salt peb Million of Water 



Date 



(a) Nov. 28, 1899-Jan. 18, 1900. 



(b) Feb. i-Mar. 7, 1900 



(c) Aug. i-Aug. 14, 1900 



(d) Aug. 15-Aug. 28, 1900 



(e) Sept. i-Sept. 28, 1900 



(f) Sept. 29-Nov. 5, 1900 



Total 



Salts 



1168 

 1136 



541 

 925 

 471 



108; 



Composition of the Waters 



Na 



312 



280 



823 

 - 7 7' 



CI 



401 

 383 

 965 



574 

 304 



SOi 



155 

 165 

 947 

 130 

 964 

 H5 



C0 3 



653 



693 



no 



1 27 



Ca 



524 

 663 

 686 

 836 

 57i 

 937 



Mr 



264 

 289 

 175 

 157 

 121 

 248 



17 



138 



226 

 151 



SiOj 



752 

 652 



266 

 5" 



(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 Context of Sevier R t ver, 

 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 



