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 respective 

 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 midsmrf position on the pier, 

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

 were determined by observing the movement of a small wooden block floating on 

 the water surface. 



Results 



Aimual mean and mean currents for 1980 through 1995 are presented in 

 Table 6 and in Figure 16. Figure 1 6 shows the daily and average annual 

 measiuements 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 



