248 



and is of relatively minor significance in the problem at 



r^/ 



^r 



,if 



hand. Eddy diffusion, on the contrary, is a process whose ' 

 importance is exceeded only by its complexity. This does 

 not imply that a discussion of eddy diffusion is without 

 merit or that no further attempt should be made to investi- 

 gate the phenomenon on both an experimental and a theoretical 

 basis. A thorough investigation of eddy diffusion eventually 

 must be made before assured predictions can be made of the 

 rate of physical dilution of any substances which may be 

 discharged into the sea. This matter is of particular impor- 

 tance to the Los Angeles area, not only because of sewage 

 and industrial waste, but because of the probability that 

 disposal of radioactive waste will certainly become of great 

 concern in the near future. 



During the first few months of this survey, an attempt 

 was made to obtain information on the coefficient of eddy 

 diffusivity from drift card returns, and to lay a foundation 

 in case it became necessary later to attack the matter of 

 diffusion as a major issue. For various reasons such a 

 research program was not established. However, it is appro- 

 priate to present the results of the preliminary work accom- 

 plished. 



Twenty analyses of drift card returns were made at stations 

 from which the drift was predominantly toward the shore and 

 from which some estimate could be made as to the radius of the 

 area occupied by the cards. The method used was a modification 

 of that of McEwen (1950), who states that; 

 A = (r,» - r») /2X'(T, - T. ) 





