Table A4 



Beach Response Classifications (from Pope and Dean (1986)) 



Beach Response Index 



Classification 



1.0 



Permanent tombolos 



2.0 



Periodic tombolos 



3.0 



Well-developed salients 



4.0 



Subdued salients 



5.0 



No sinuosity 



Table A5 



Breakwater Length/Distance Offshore vs Beach Response 



>-, 



X 



s 



X | L„ 



X 



L,/X 



Beach Response 

 (Ahrens and Cox 

 1990) 



50 

 50 



200 



100 



75 

 75 



300 

 150 



100 

 100 



400 

 200 



.25 

 .50 



5.0/no sinuosity 

 4.5/no sinuosity 



50 



75 



75 



112 



100 



150 



.67 



4.2/subdued 

 salients 



50 



67 



75 



100 



100 



133 



.75 



4.1 /subdued 

 salients 



50 



50 



75 



75 



100 



100 



1.00 



3.7/subdued 

 salients 



50 



40 



75 



60 



100 



80 



1.25 



3 .3/well-developed 

 salients 



50 



33 



75 



50 



100 



67 



1.50 



3 .0/ well-developed 

 salients 



50 



29 



75 



43 



100 



57 



1.75 



2.7/well-developed 

 salients 



50 



25 75 



38 



100 



50 



2.00 



2.5/periodic 

 tombolos 



through the gaps (e.g., smaller gaps, with the resulting increase in the length 

 of breakwater segments) or to add beach fill to the shoreline area. In the 

 latter application, the function of the breakwater system is to reduce the wave 

 energy level such that the beach fill will form a stable equilibrium planform 

 and dissipate the remaining wave energy prior to its reaching the toe of the 

 bank. 



A10 



To evaluate the potential wave transmission characteristics of various 

 breakwater gaps, nearshore diffraction diagrams were developed for the lee of 

 the breakwaters for each design event. Analysis of the diagrams indicated that 

 the 50-yr design wave height of 7.2 ft would be reduced to about 3 ft at a 

 distance of about 45 ft from the toe of the bank for breakwater gap widths of 

 100 ft, the minimum gap width considered practical for the area. Assuming a 



Appendix A Case Design Example of Detached Breakwater 



