PART IV: CONCLUSION 



34. Based on extensive discussions with Corps division and district 

 personnel and after the review of prototype experience relative to rubble- 

 mound toe stability problems, it is concluded that design guidance is 

 seriously needed on the proper sizing and placement configurations needed to 

 provide adequate buttressing stone and toe berms for rubble-mound coastal 

 breakwaters and jetties. Once it is understood how to design toe berms and 

 buttressing stone for a range of water levels and wave conditions, these 

 designs need to be incorporated into a test series that addresses the way in 

 which varying toe geometries influence localized scour. The latter will pro- 

 vide some qualitative insight into how a toe berm can be configured or 

 positioned to reduce the quantity and/or rate of localized foundation scour. 



78 



