So 



w 



»- 

 u. 



III 



a 

 111 



n 



-s 



i 



u>: 

 S3 



M 



tfl 



_l" 



p5 



200 



60 



50 



40 



9.0 



80 



7.0 



70 



60 



~: 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC. 



COLUMBIA RIVER AT PASCO 



Average Monthly Water Quality 

 1954-1957 



FIG. II 



34 



