Substituting in values from Tables 4 and 6 and with Ra = 3 , the annual 

 volumetric change due to alongshore transport was 



Qin " Qout - "86,125 m 3 /yr 

 From equation (11) 



Qin " Qout = (Pl in - Pl out ) 

 and from Figure 38 



Pi . -Pi _ = -300 N-M/S-M 

 , , i in x out 



and hence 



/3 =28 7 m 3 -s/Nyr 



Within the limits of accuracy of both the data and technical analyses, 

 this simple postfill sediment budget determination, where all 

 contributions to the sediment budget were quantified, produced a value 

 of /3 which was very close to that calculated earlier (mean value of 

 /3 = 300) when using long-term beach response characteristics and where 

 the losses due to sorting of "freshly" exposed native beach material by 

 ongoing erosion was assumed to be small. Since the calculated values of 

 are similar and they come from analyses of two distinct phases of 

 beach response, these results support the contention that ongoing 

 sorting losses during the long-term response phase are minimal. 



Analysis of the spatial variation of the beach response to the 1965 

 and 1971 beach fills along Carolina Beach was not possible because of 

 insufficient profile information. Results for the 1965 fill, as shown 

 by the beach photos in Figure 46, were determined from MLW, MSL, and MHW 

 excursion distance plots for profiles CB106 and CB107 which were less 

 than 0.5 kilometer apart. Consecutive profiles at CB97 were used to 

 determine the response to the 1971 beach fill. The average exponential 

 decay constant, the average initial fill excursion, and the average 

 long-term erosional rate are given in Table 12. Substituting these val- 

 ues into equation (4) indicates that most initial losses occurred during 

 the first 1.5 to 2 years following both fills, in agreement with 

 observed behavior (U.S. Army Engineer District, Wilmington, 1970). 

 Using the values contained in Table 12 and assuming C, =0 .8, equation (6) 

 predicts that 2.4 years and 2.25 years after the 1965 and 1971 fill 

 projects, respectively, the beach face eroded to approximately its 

 original prefill position. These values are in reasonable agreement 

 with recorded observations on the loss of beach fill during the 2 years 

 following each fill (U.S. Army Engineer District, Wilmington, 1977). 



Granulometric data taken immediately after fill placement in 1965, 

 and taken again 2 years later, are shown in Table 21. These data were 

 used to calculate a critical ratio of 2.1 for the fill material, and 

 thus an expected 55 percent volumetric loss due to sorting (U.S. Army 

 Engineer District, Wilmington, 1970). Results from profile CB106 tend 

 to show that 50 percent of the initial excursion was lost during the 

 first 1.5 to 2 years, close to the design value. The adjusted fill 

 factor and James' (1975) renourishment factor were evaluated from the 

 same data and were found to be R A =1.02 and Rj=0.25, respectively. For 

 the 1965 Carolina beach-fill data, the adjusted fill-factor techniques 

 predicted a value of expected sorting loss significantly lower than both 



90 



