

. 46 - 5 ' . 







+II.4'NGVD\ 



r 50 ' 



^e'/vsk/? 













1-1/2/ 



"/ w 



"^£ ¥ 



l i 



OVERTOPPING 

 CONTAINER 



1 1 



2 



/ 



5f/JC// i//Vf 3 .5' I 





~~~~~~ BEDDING LAYER 

 1 1 1 1 1 





1 



24 23 22 



DISTANCE ALONG TANK FLOOR, FT 



LEGEND 



STONE WEIGHT, W 5 q 



W 4718 LB 



Figure 18. Configuration 9, seawall with beach breakwater 



beach breakwater and the seawall inspired considerable confidence since both 

 represent formidable discontinuities to waves and runup flow and a consider- 

 able amount of armor stone was used to dissipate wave energy. Figure 19 shows 

 how the beach breakwater appeared in the model study. It appears that one 

 problem with the beach breakwater was the lack of distance between the break- 

 water and the seawall to dissipate as much wave energy as could potentially be 

 achieved from all the turbulence that was introduced by the breakwater. How- 

 ever, if the breakwater were moved farther offshore it would be in deeper 

 water and therefore require a larger structure making construction more dif- 

 ficult. There is also the problem that the breakwater requires larger armor 

 stone because it has to be built with steeper side slopes than the revetment 

 in order to fit into the allocated space. In addition, the beach between the 

 breakwater and the seawall needs to be armored to prevent scour. Probably 

 because of the roughness and high porosity of all the armor stone there was no 

 tendency for wave resonance to be observed in the pond formed between the 

 breakwater and seawall. The added complexity of building a beach breakwater 

 compared to a revetment against the seawall suggests that the breakwater would 

 not be cost effective. 



26. Configuration 10 (Table 1 and Figure 20) is a sheet-pile seawall 

 with a standard riprap revetment fronting it. A plot of Q versus F' for 



27 



