If the calculated wave steepness exceeds the value of 0.142, the deepwater 

 wave height is reduced to satisfy Equation 21, maintaining input wave period 

 at the same value. A warning message is also issued. 



Wave Energy Windows 



161. The concept of wave energy windows is central to GENESIS and 

 determines its algorithmic structure. Wave energy windows provide a powerful 

 means of describing breaking wave conditions alongshore and the associated 

 sand transport for a wide variety of configurations of coastal structures. 



Energy windows 



162. An energy window is an area open to incident waves as viewed from 

 a particular stretch of beach. Operationally, an energy window is defined by 

 two boundaries that are regarded as limiting the penetration of waves to the 

 target beach. Windows are separated by diffracting jetties, diffracting 

 groins, nontransmissive detached breakwaters, and the tips of transmissive 

 detached breakwaters. (The term "transmission" refers to the transmission of 

 waves through or over a detached breakwater.) Incident wave energy must enter 

 through one of these windows to reach a location in the nearshore area. It is 

 possible (and common) for a location to be open to waves from more than one 

 window. 



Sand transport calculation domains 



163. At the present stage of model development, shore -connected struc- 

 tures (jetties, groins, and breakwaters) are assumed not to transmit wave 

 energy, so that waves entering on one side of such a structure cannot propa- 

 gate to the other side. Based on the concept of wave energy windows and non- 

 wave transmissibility of shore -connected structures, the shoreline is divided 

 into what are called "sand transport calculation domains." These domains 

 consist of segments of the coast bounded on each side by either a diffracting 

 shore -connected structure or a model boundary . GENESIS solves the shoreline 

 change equation independently for each domain, except for conditions such as 

 sand passing around or through groins, which allow exchange of sand across the 

 boundaries of the calculation domains. 



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