berm, and the slope of the step depends on the properties of the runup bore 

 and the sand grains. Under storm wave action a scarp may also form; here, the 

 term "step" will sometimes be used to denote both a scarp and a step. On many 

 beaches a line of dunes is present shoreward of the backshore . Dunes consist 

 of large ridges of unconsolidated sand that has been transported by wind from 

 the backshore . 



15. A bar is a depositional feature formed by sand transported from 

 neighboring areas. Several bars may appear along a beach profile, often 

 having a distinct trough on the shoreward side. Bars are highly dynamic 

 features that respond to the existing wave climate by changing form and 

 translating across - shore , but at the same time bars influence the waves 

 incident upon them. If a bar was created during an episode of high waves, it 

 may be located at such great depth that very little or almost no sand trans- 

 port activity takes place until another period of high waves occurs. Some 

 transport from the bar caused by shoaling waves may take place, but the time 

 scale of this process is considerably longer than if the bar is located close 

 to the surf zone and the breaking or broken waves. 



Nearshore waves 



16. The above-discussed terminology is related mainly to the various 

 regions and features of the beach profile. Nearshore waves are also described 

 by a specialized terminology (Figure lb) . Again, some definitions are not 

 unique and describe quantities that change in space and time. The region 

 between the break point and the limit of the backrush, where mainly broken 

 waves exist, is called the surf zone. The swash zone extends approximately 

 from the limit of the backrush to the maximum point of uprush, coinciding with 

 the region of the beach face. As waves break and propagate toward shore, 

 reformation may occur depending on the profile shape; that is, the translatory 

 broken wave form reverts to an oscillatory wave. This oscillatory wave will 

 break again as it reaches sufficiently shallow water, transforming into a 

 broken wave with considerable energy dissipation. A region where broken waves 

 have reformed to oscillatory waves is called a reformation zone, and the point 

 where this occurs is the wave reformation point. Depending on the regularity 

 of the incident waves and shape of the beach profile, wave breaking and 

 reformation may occur several times . 



15 



