IRRIGATION PRACTICE 



DISSOLVED SUBSTANCES IN RIVER WATERS 

 (Parts per million) 



It will be observed that, in the United States, the 

 waters of highest average purity, that is, of lowest con- 

 centration, are those on the Atlantic Coast; those of the 

 Mississippi Basin and of the great Northwest come next; 

 the waters of the southwestern rivers, including the 

 Colorado, are still higher in their average content of solu- 

 ble matter; while those of the California rivers stand 

 between those of the Mississippi River and those of the 

 Southwest. The rivers of the Great Basin, which, after a 

 short journey from the mountain headwaters, reach the 

 interior lake into which their load is deposited, are less 

 concentrated than the rivers of the Southwest and more 

 like those of the Mississippi River Basin. 



