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that flows in the direction of the wind, according to the 

 rule that the lighter water shall be on the right-hand side 

 of the current. Warm water placed adjacent to the coast by 

 other means, such as that developed by the outfalls in Santa 

 Monica Bay, also results in currents of this nature. 



Now consider a wind with the coastline on the left of 

 the direction of travel. Light and warm water is necessarily 

 transported away from the coast and is replaced by denser 

 and colder subsurface water. This process, which is know as 

 upwelling , also leads to an altered distribution of density 

 to which a current flowing in the direction of the wind 

 corresponds. 



Each of these wind effects occurs in Santa Monica Bay 

 and is instrumental in developing water motion which can be 

 readily identified by horizontal temperature patterns. In 

 many instances, it can be shown that the flows along isotherms 

 are directly related to wind directions, but modifications 

 occur which are not so easily interpreted. Other factors, 

 therefore, must be effective in modifying the density flows. 



Tidal Currents . Tidal currents do not bring about the 

 transport of water over large distances. They vary from one 

 locality to another, depending upon the character of the tide, 

 the depth to the bottom, and the configuration of the coast, 

 but in any given locality they repeat themselves as regularly 

 as the tides to which they are related. The most important 

 aspect of the tidal currents in coastal areas is that they 

 contribute greatly toward the stirring of water layers. Be- 

 cause of their minor effect on net water motion, they frequently 

 are obscured by the forces of density slopes. 



