Values of measured q-r were taken from all profiles along the 

 beaches away from the immediate area of inlet influence. Unfortunately, 

 due to the insufficient temporal and spatial distribution of profile 

 data, volumetric change data for Masonboro, Kure, and Fort Fisher 

 Beaches were not calculated. Only values for Wrightsville and Carolina 

 Beaches, in Tables 7 and 10, were compared to predicted values. A plot 

 of q^ anc * B (dPi/dX), versus beach distance X, was drawn by 

 choosing a value of B which produced the best correlation between the 

 two lines. To eliminate sudden computational fluctuations before 

 comparison with measured q^ values, the /3 dP^/dX values were 

 filtered to produce smoothly varying distribution. 



Figures 39 and 40 show the results of these comparisons for 

 Wrightsville Beach and Carolina Beach, respectively. Although consid- 

 erable scatter in the values of q^ is obvious, especially along the 

 northern Carolina Beach region, the general trends of both the computed 

 and measured volumetric change values are similar along each beach. 



Within the limitations of the analysis, it appears that a value of 

 B "300 nH-s/N-yr provides the best fit for Wrightsville Beach with a 

 data scatter of +33 percent. For Carolina Beach, the best-fit value is 

 B =900 m^-s/N-yr with a data scatter of +66 percent. These results 

 as summarized in Table 16, show a large possible range in values of B. 

 Assuming that equation (11) is a valid representation of the relation- 

 ship between the longshore sediment transport rate and the longshore 

 component of wave energy flux, then two possible conclusions can be 

 made. First, the value of B is highly localized and strongly dependent 

 on the local physical characteristics of the beach and sediment 

 properties. Table 3 shows that the sediment characteristics do change 

 along these beaches, and differences in offshore beach slopes between 

 Wrightsville Beach and Carolina Beach were discussed in Section II. The 

 second possible conclusion, and probably the more dominant one for this 

 study, is that the value of B is very sensitive to the method of com- 

 putation of the variables in 'the rates qL/CdP^/dX). In particular, 

 errors inherent within the refraction analysis technique can result in 

 significant spatial variation of the energy flux and hence in the 

 dP-^/dX values. This variation is then reflected in the spatial 

 variation of the B values. 



Table 16. Values of B for Wrightsville and Carolina Beaches. 



Beach 



Values of p in units of m -s/N-yr 



Best fit 



Lower bound 



Upper bound 



Wrightsville 

 Carolina 



300 

 900 



200 

 300 



400 

 1,500 



76 



