226 ALKALI WATER FOR IRRIGATION 



Numerous analyses of river and canal waters show the 

 great quantities of soluble salts added to the streams by 

 seepage water. In Colorado, a river increased in total 

 salts from no parts per million to 1178 parts per million 

 in traveling 20 miles (28); the Jordan River, Utah, in a 

 course of 14 miles changed from 890 parts per million total 

 salts to 1970 parts per million (n); the Sevier River, 

 Utah (12), in running from Junction to Sigard, a distance 

 of 60 miles, had its total salt content increased from 205 

 parts per million to 831 parts per million and by the time 

 it had reached Delta, 150 miles from Junction, its salt 

 content had reached 1316 parts per million; the Pecos 

 River, at Roswell, New Mexico, contained 760 parts per 

 million total salts, and about 30 miles below 2020 parts 

 per million were found and there were corresponding in- 

 creases until at a point about 150 miles below the last- 

 mentioned place, the river contained over 5000 parts per 

 million (n) (8). These rivers all illustrate the amount 

 of contamination from seepage water that may occur in 

 almost any river. 



At places where drainage water from strongly alkali 

 soils empties into streams even greater pollution of the 

 water may be expected. Water passing through a soil 

 containing 20,000 parts per million of alkali in the upper 

 four feet has been found to contain over 34,000 parts per 

 million of salts when it reached the drainage outlet (5). 

 Such water emptying into the bed of a small stream, as 

 is frequently done during the height of the irrigation 

 season, may make the further use of this water extremely 

 dangerous. The water of the Arkansas River is very 

 pure at Canon City, Colorado, but it is entirely diverted 

 for irrigation further down. At a point about 120 miles 

 below where seepage had increased the stream to consider- 



