247 



possible conditions using both maximum and "average" velo- 

 cities. Whenever the time of drift was greater than about 

 4 days and the flow was out of the bay, no velocities were 

 computed » 



It is believed that the reliability of the information 

 presented here is good. It is true that the actual trajec- 

 tories of individual cards is not known, but those which 

 showed the greatest velocities were, in nearly all cases, 

 those which came most directly inshore. The distances 

 travelled were measured along a line between the station and 

 the points of recovery, and in those instances where the cards 

 described an arc on their journey, or came inshore and were 

 then carried to the south or north by a littoral current, 

 some error therefore may be introduced. But whenever it 

 appeared that the drift departed significantly from a straight 

 line, a correction factor, arbitrary in each case to be sure, 

 was applied. In short, every consideration was given so that 

 the results, if they erred, would err on the side of increasing 

 velocities. This approach is justified considering the pmr- 

 pose of the survey, 



Eddy Diffusion 



Sewage discharged into the ocean may be transported by 

 currents, but its dilution with the passage of time caji be 

 accomplished only by turbulent mixing and by vertical and 

 horizontal eddy diffusion. In Santa Monica Bay turbulent 

 mixing due to convectional overturn (cooling or evaporation), 

 or to stirring of the waters by strong winds occurs infrequently 



