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waters in the bay are generally calm with only light to 

 moderate afternoon seas, and low short swells to disturb 

 the surface. Rarely, winds of Force 5 or greater blow from 

 the northwest causing rough water in the southern and central 

 part of the bay, but leaving the protected northern portion 

 still in a state of near-calm. A swell with a period longer 

 than 10 seconds is rare. Destructive waves are, therefore, 

 nearly unknown in the bay except in the vicinity of Redondo 

 where the bottom topography causes extreme modifications of 

 the wave trains in the surf zone. 



Current action in the waters is likewise gentle. It is 

 established primarily by winds, and since they are usually of 

 low velocity, the resulting wind drift and density currents 

 are also slow. In the shallow nearshore area there is an 

 oscillating motion due to the tides. Such tidal motion is 

 normally parallel to the coast, but is frequently modified 

 by density currents which also move in a north or south 

 direction parallel to the eastern shores of the bay. 



Because the water moves slowly in and out of the bay 

 and because the net motion is determined by the interaction 

 of several different forces, complicated patterns of water 

 structure result. The Shelf Water Mass, which exhibits 

 characteristics of deeper water from over the continental 

 borderland, is almost always capped nearshore by a warm low- 

 salinity water unit originating from the Hyperion outfall, . 

 Ballona Creek, and the Edison Company power plant. At times, 

 this unit may become so dominant that it establishes density 

 slopes and subsequent water motion over and above that normal 



