help uncover erroneous or misleading results. Plots of computed shoreline 

 positions reveal obvious modeling mistakes, whereas more subtle errors of 

 either the model or modeler can be found in the sensitivity analysis through 

 understanding of basic dependencies of shoreline change on the wave input and 

 boundary conditions. 



94. Shoreline change is governed by nonlinear processes, many of which 

 are represented in GENESIS. Complex beach configurations and time -dependent 

 wave input will produce results that cannot be extrapolated from experience. 

 However, as much as possible, experience should be called upon to evaluate the 

 correctness of results and to comprehend the trends in shoreline change 

 produced . 



95. Finally, the user must maintain a certain distance from model 

 results. It should be remembered that obliquely incident waves are not 

 responsible for all longshore sand transport and shoreline change. Potential 

 errors also enter the hindcast of the incident waves, in representing an 

 irregular wave field by monochromatic waves and, sometimes, through undocu- 

 mented human activities and extreme wave events that have modified the beach. 

 The probable range in variability of coastal processes must also be considered 

 when interpreting model results. 



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