4 Currents 



Surface current speed and direction at the FRF are influenced by winds, 

 waves, and, indirectly, by the bottom topography. The extent of the respec- 

 tive influences varies daily. However, winds tend to dominate the currents at 

 the seaward end of the pier, whereas waves dominate within the surf zone. 



Observations 



Near 0700 EST, daily observations of surface current speed and direction 

 were made at (a) the seaward end of the pier, (b) the midsurf position on the 

 pier, and (c) 10 to 15 m from the beach 500 m updrift of the pier. Surface 

 currents were determined by observing the movement of dye on the water 

 surface. 



Results 



Annual mean and mean currents for 1980 through 1994 are presented in 

 Table 6 and in Figure 16. Figure 16 shows the daily and average annual 

 measurements at the beach, pier midsurf, and pier end locations. Since the 

 relative influences of the winds and waves vary with position from shore, the 

 current speeds and, to some extent, direction vary at the beach, midsurf, and 

 pier end locations. Magnitudes generally are largest at the midsurf location 

 and lowest at the end of the pier. 



Chapter 4 Currents 



35 



