Nearshore Currents 



14. Longshore currents inside the breaker line are associated in direc- 

 tion and strength with wave height and direction, being generally strongest 

 and to the south (though with frequent reversals) in fall and winter and more 

 predominantly to the north in spring and summer. 



15. Rip currents occur frequently in the area, especially at cuts in 

 the offshore sandbar, such as the one underneath the pier. 



Tides and Water Level Changes 



16. Ocean tides at the FRF occur semidiurnally, with a mean range of 

 1.0 m. Local mean sea level (MSL) since 1978 has been 8 cm above the 1929 

 NGVD. Water levels in Currituck Sound are wind-dominated rather than tidal, 

 being low when winds are northeasterly and high when they are southwesterly. 



Sediment Size 



17. Offshore material decreases in mean grain size and becomes in- 

 creasingly well sorted with distance from shore. Mean sizes vary from 0.4 mm 

 (1.31 phi) near the shore to 0.12 mm (3.11 phi) at the 15-m-depth contour, 

 about 2,000 m offshore. 



18. Mean grain size of beach sand decreases from 0.52 mm (0.9 phi) at 

 the mean low water (MLW) line to 0.38 mm (1.4 phi) at the dune. The sediment 

 has a bimodal distribution of coarse material mixed with much finer sands. 

 Mean foreshore sand sizes are smallest in the summer when wave energies are 

 lowest. 



Bathymetry 



19. Nearshore bathymetry at the FRF is characterized by regular shore- 

 parallel contours, a moderate slope, and two bars, with a wide outer bar and 

 a well defined inner bar. This pattern is interrupted in the immediate 

 vicinity of the pier by a shallow trough which runs the length of the pier, 

 ending in a scour hole under the seaward end of the pier which measures up to 

 3.0 m deeper than the adjacent bottom. 



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