*? 



40 

 .30 

 .20 



.10 

 



i 1 r 



t 1 1 1 r 



-i 1 1 1 r 



DISSOLVED OXYGEN 



-i 1 1 1 1 1 1 1 1 1 1 1 1 1 r 



CONDUCTIVITY 



JUL. ' AUG. ' SEP. ' OCT. ' NOV. ' DEC. ' JAN. ' FEB. 1 MAR. 1 APR. 1 MAY ' JUN. ' JUL ' AUG. ' SEP. ' OCT. ' NOV. ' DEC. 



1967 



1968 



Figure 7, 



--Average pH (a), dissolved oxygen (b), conductivity (c), and salinity (d), in the lower Columbia River, July 1967 



through December 1968. 



