Basic Terminology 



12. Nomenclature associated with the beach profile and nearshore region 

 which is used throughout the report is presented in this section. Terms 

 defined in the Shore Protection Manual (SPM 1984) have been adopted to a large 

 extent. However, for some quantities, slightly different descriptions are 

 employed that are better suited for nearshore processes as related to beach 

 profile change. Figures la and lb are definition sketches pertaining to beach 

 profile morphology and nearshore wave dynamics, respectively. The portion of 

 the beach profile of interest spans across the shore from the dunes to the 

 seaward limit of the nearshore zone. 



Profile morphology 



13. As waves approach the beach from deep water, they enter the near- 

 shore zone. The seaward boundary of the nearshore zone is dynamic and for our 

 purpose is considered to be the depth at which incident waves begin to shoal. 

 The shoreward boundary of wave action is also dynamic and is at the limit of 

 wave runup located at the intersection between the maximum water level and the 

 beach profile. A gently sloping bottom will cause a gradual shoaling of the 

 waves , leading to an increase in wave height and finally to breaking at a 

 point where the wave height is about equal to the water depth. The region 

 seaward of wave breaking is denoted as the offshore; the inshore encompasses 

 the surf zone, i.e., that portion of the profile exposed to breaking and 

 broken waves. The broken waves both propagate and dissipate with large energy 

 through turbulence, initiating and maintaining sand movement. At the beach 

 face, the remaining wave energy is expended by a runup bore as the water 

 rushes up the profile. 



14. The flat area shoreward of the beach face is called the backshore 

 and is only wetted during severe (storm) wave conditions or when the water 

 level is unusually high. On the backshore, one or several berms may exist; 

 these are accretionary features formed of material which has been deposited by 

 wave runup. The term "accretionary" refers to features generated by sand 

 transport directed onshore. A step often develops immediately seaward of a 



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