1961 



250 

 500 

 i.OOC 



RZ 



H-16 I H-l? 



HSP 



1962 



-0 448'N 



1963 



1964 



Figure 7. — Vertical profiles of July temperature along 

 lat. 44° N. (approximately). Longitudinal relations be- 

 tween profiles are preserved. Sea floor is stippled. 

 Contour interval is 1° C. Depth scale is logarithmic. 

 Cobb hydrographic stations are identified along the top 

 of each profile. The letter Z refers to depth. 



H-21 H-22 H-23 H-24 



1964 



Figure 8. — Vertical profiles of July salinity along lat. 

 44° N. (approximately). Longitudinal relations between 

 profiles are preserved. Sea floor is stippled. Contour 

 interval is 0.2°/oo except where shaded. Depth scale is 

 logarithmic. 



annual discharge from all rivers along the Oregon- 

 Washington coast (Budinger et al., 1964); pfob- 

 ably it is the sole contributor of fresh water to the 

 plume pro\ance in summer. For this reason, salt 

 distribution in the surface layers of the plume 

 province is predominantly influenced by Colum- 

 bia River effluent at all times of the year. This 

 effluent now enters the ocean at approximately the 

 ambient offshore temperature, although its aver- 

 age temperature may increase in future summers 

 as the number of Columbia River Basin impound- 



ments increases and the June discharge pulse 

 decreases.' 



This discharge creates a plume of low-salinity 

 water which in summer extends southwest from 

 its source, in response to currents and to wind 

 stress. Studies of the effluent by Budinger et al. 

 (1964) indicated that estuarine mixing introduces 

 into the open sea a mixture that consists approxi- 

 inately of one jmrt river water with two parts sea 

 water. Once a parcel of this mixture is at sea, 



■ This temperature increase may or may not be reflected in plume tempera- 

 tures in future years. 



510 



U.S. FISH AND WILDLIFE SERVICE 



