181 



from the standpoint of meeting pollution standards at the 

 beach, it also became apparent that there was a possible gap 

 in recoveries during the important interval of from 8 to 22 

 hours after releasing the cards. Accordingly, on the cruises 

 of May 23, July 26, August 9, and August 20, 1956, cards were 

 dropped between about 9 p.m. and 3 a.m. This procedure made 

 it possible to recover cards should they wash ashore during 

 the critical interval. In no instance was a card recovered 

 early the following morning from a sludge or effluent 

 station. This fact increases the reliability of computations 

 of maximum drift velocities from those stations. 

 Explanation of Drift Card Charts 



The distribution of stations over the bay on most cruises 

 was similar to that on September 8, 1955 (Fig. 81). Station 

 charts for individual cruises, therefore, are presented only 

 when special conditions require their being included. 



Stations located at or near the proposed outfall terminals 

 are indicated by solid circles? all other stations are indi- 

 cated by open circles. 



On charts showing the returns of drift cards, the station 

 number and the nvunber of returns over the number released 

 (i.e., 6/25) are written immediately below each point of release. 

 Lines representing assumed paths or directions of flow from 

 individual stations or from groups of stations are drawn. When- 

 ever two sets of figures are written at the ends of the arrows 

 or along the flow lines, the first indicates the travel time 

 in days (unless otherwise indicated) and those in parentheses 

 give the number of cards recovered at each locality. Whenever 



