detailed investigation of the imposed boundary condition at the pier was 

 performed (Gravens 1990), and the conclusion was that the boundary condition 

 imposed at the Huntington Pier had no significant effect on the model results 

 northeast of the sea cliffs over the modeling interval. 



Finally, in the vicinity of the proposed entrance system (between 

 alongshore coordinates 155 and 220), the predicted and measured shoreline 

 positions are in very good agreement. Model results for this region are 

 considered to have high reliability. 



Average annual net and gross longshore sand transport rates calculated 

 by the model are presented in Figure 5. Also given in Figure 5 are the net 

 transport rates for the year which produced the maximum southerly and maximum 

 northerly littoral drift rates. These curves are presented to point out the 

 profound variability in both the direction and magnitude of the net longshore 

 sand transport rate which can be encountered from year to year depending on 

 the incident wave climate. It should be noted that there is a reversal in the 

 average annual net longshore transport direction in the vicinity of the 

 proposed entrance system. This unique feature is very important with regard 

 to the proposed entrance system impacts on adjacent shorelines, indicating 

 that the entrance would have minimal adverse impact on adjacent shorelines. 



AVERAGE ANNUAL LONGSHORE SAND TRANSPORT RATE leu yd X 10 i ] 

 CALIBRATION 



, AVERAGE GROSS SAND TRANSPORT RATE/10. 



MAXIMUM NORTHERLY SANO TRANSPORT RATE 



100 120 140 160 180 200 220 2+0 260 



ALONGSHORE COORDINATE 



Figure 5. Average annual longshore sand transport rates (1963-1970) 



76 



