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Groin Spacing/Lengtii Ratio 



1 ■! 

 4 



Figure 15. 



Minimum distance to baseline (seawall) versus groin spacing/length 

 ratio 



(1991) applied GENESIS to examine predictions against physical model results 

 for multiple straight groins and shore-parallel detached breakwaters. 



Hashimoto, Uda, and Takebuchi (1981) conducted experiments in a large 

 physical model basin (16-m longshore by 20-m cross-shore) to evaluate the func- 

 tioning of four structural configurations for shore protection from winter-wave 

 conditions on the Pacific coast of Japan. The physical model was constructed at 

 1 :50 scale, and the basin configuration for their Case 4 is shown in Figure 16. 

 The 0.27-mm median grain-size sand was molded into a profile shape represent- 

 ing that of the prototype. The initial beach profile was constructed with a 

 1/10 slope from the still-water line to a depth of 10 cm. tapering to a 1/70 slope 

 to a distance of 8 m offshore where the slope reverted to 1/10 to a depth of 

 40 cm. 



Cases 1 and 4 of this laboratory study were simulated using GENESIS 

 (Hanson and Kraus (1991) evaluated Cases 1 and 3). Case 1 is configured with 

 three groins extending 1 .8 m seaward of the initial shoreline, spaced 6 m apart 

 with the outermost groins located 2 m from the lateral boundaries of the wave 

 basin. The groins were constructed of small concrete blocks that extended well 

 above the water surface and were impermeable to waves. The configuration for 

 Case 4 was similar to that of Case 1 with the addition of 1 .2-m-long T-heads to 

 the groins. Incident wave conditions for the physical model tests were 



16 



Chapter 3 Functional Design 



