than the existing 1970 prefill beach slope. During the first 9 to 

 12 months the MHW-MLW beach slope steepened (and retreated) in response 

 to the seaward sorting of fine sand grains and to the readjustment of 

 the profile slope to the prevailing wave conditions. After this period, 

 the upper beach face retreated with only minor changes in beach slope 

 due to seasonal wave climate influences. 



Sediment characteristics of the fill and native beach material were 

 used to calculate a value for the adjusted fill factor of R^=3.0. 

 This value indicates that 66 percent of the fill material can be 

 expected to be lost due to sorting; however, comparison with measured 

 results indicates that this calculation underestimates the initial loss 

 percentage. In addition to the sorting and slope readjustment losses, 

 significant quantities of fill material were lost due to the lateral 

 spreading of material onto adjacent beaches. 



An oblique aerial photo taken before the 1970 beach fill showed that 

 the placement of the fill could only have reinforced the beach alinement 

 problem along Wrightsville Beach. Since 1965, the beach section which 

 suffered the localized and high erosion rates protruded from the 

 generally smooth, curving beach planform. It was concluded that the 

 relative change in beach planform and nearshore bathymetry resulted in 

 an increase in localized wave activity, sediment transport potential, 

 and erosional trends, and that this phenomena would continue until the 

 relative change in beach shape is eliminated. Therefore, it appears 

 that the continual renourishment of this section perpetuated the problem 

 of increased localized wave activity. 



This study showed that beach losses in addition to the expected 

 losses due to sorting and slope readjustment occurred during the initial 

 1.5- to 2-year response phase. It appeared that lateral spreading of 

 the fill material onto adjacent beaches, due to the forced protrusion of 

 the beach fill out beyond the general beach alinement, resulted in these 

 additional significant losses. 



95 



