this northern beach area was 68,000 cu yd/year (O'Brien 1931).* Between 1982 

 and 1984 the rate of accumulation was 337,000 cu yd/year. However, not all of 

 this increased rate of accumulation can be attributed to Carolina Beach Inlet, 

 as there has also been an increase in the rate of northward sediment transport 

 off the north end of the Carolina Beach fill. 



46. Plan views of the average foreshore position of Carolina Beach 

 before the 1982 fill, immediately following the 1982 fill, and in June 1983 

 and May 1984 are shown in Figure 10. Also shown in this figure is a hypo- 

 thetical equilibrium shoreline that would probably form if the rubble-mound 

 seawall at the north end of the project was removed and periodic beach nour- 

 ishment discontinued. This hypothetical equilibrium shoreline simply connects 

 in the south with shoreline unaffected by the seawall, and in the north with 

 the portion of the beach where inlet effects dominate. Compared to the hypo- 

 thetical shoreline, the actual beach planform protrudes seaward forming a 

 rather large bulge between sta 70+00 and 150+00, particularly for the shore- 

 line following the placement of the 1982 fill. Between baseline sta 115+00 

 and 150+00, waves arriving from the southern quadrant would have broken at a 

 much larger angle than normal relative to the post- 1982 fill shoreline, while 

 waves originating from the northern quadrant would have smaller than normal 

 breaker angles along this reach. This deviation in wave breaker angles from 

 the normal case would have produced a larger northward littoral transport 

 between sta 115+00 and 150+00 and a reduced southerly rate over this same 

 reach. The postfill shoreline shape would have also caused the net southerly 

 sand transport to be higher than normal between sta 115+00 and 70+00. Some 

 evidence of these altered sand transport rates is available from the volumet- 

 ric changes that occurred between various profile survey stations on Carolina 

 Beach which are summarized in Table 5. From the as-built condition in 1982 to 

 June 1983, the shoreline between sta 120+00 and 150+00 accreted 139,400 cu yd 

 while the adjacent sections both north and south of this reach eroded. Simi- 

 larly, the beach between sta 100+00 and 40+00 gained 109,100 cu yd during the 

 same period, again while the adjacent sections eroded. The accretion of 

 material in these isolated zones, which are located near the extremities of 

 the shoreline bulge, indicates that material was transported into these 

 sections faster than it could be carried away. From June 1983 to May 1984, 

 these two accretion zones also began to erode while accretion occured at 



* Op cit. 



18 



