EXPECTED SHORELINE RESPONSE - 



ORIGINAL SHORELINE 



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BREAKWATER' 



Figure 18. Possible shore response to a segmented detached 

 breakwater with incident waves normal to shore 



be prevented if the single breakwater or segment length is equal to or less 

 than one-half the distance offshore (see also Bishop 1982) , or simply 



I £ ■=• x for single detached breakwater 



H < — x for segmented detached breakwater 



This configuration permits intersection of the diffracted wave crests well be- 

 fore the undiffracted portions reach the shoreline, thereby impeding tombolo 

 development. If the predominant wave direction is nearly normal to the shore, 

 the apex of the salient will be located approximately where the diffracted 

 wave crests intersect at the moment the undiffracted portions reach the shore- 

 line. The design theory employed for Lakeview Park postulated that salients 

 would develop where the diffraction coefficient, K , equals 0.3 isolines 

 crossed (Walker, Clark, and Pope 1981). The average stable salient configur- 

 ation was estimated by examining the location of the 0.3 isoline for each pre- 

 dominant wave condition. This method is described in Appendix A. 



47. Detached breakwaters designed for protection along an open coast 

 are commonly placed in an average water depth between 1.0 and 8.0 m. If 

 economic or other considerations preclude satisfying the I or £ _< 1/2 x 



41 



