PART VIII: SUMMARY AND CONCLUSIONS 



536. The ultimate objective of this study was to develop an engineering 

 numerical model of beach profile change having the capability of simulating 

 formation and movement of major morphologic features of the profile, particu- 

 larly bars and berms . Beach profile response produced by severe storm or 

 hurricane events, with large erosion and possible dune retreat, was the 

 principal target problem of the study, although profile change occurring on 

 longer time scales, such as adjustment of beach fill, which involves accre- 

 tionary as well as erosional processes, was also of interest. A basic 

 assumption underlying this work was that major morphologic change occurring in 

 and around the surf zone is produced by breaking and broken waves. 



537. Data from two LWT experiments were used in development of the 

 numerical model; one experiment performed by the US Army Corps of Engineers 

 (CE) and the other carried out by the Central Research Institute of Electric 

 Power Industry (CRIEPI), Japan. In total, these experiments encompassed 42 

 cases having different values of wave height, wave period, water level, grain 

 size, and initial profile slope or shape. The CRIEPI experiment also included 

 measurements of wave height along the profile from prebreaking through the 

 surf zone . 



538. Extensive analysis of morphologic features of the profile was 

 conducted to provide the foundation for the numerical model, but the analysis 

 also produced functional relationships between geometric characteristics of 

 the profile and wave and sand properties. Geometric properties of the profile 

 that were quantified were bar volume, bar height, depth-to-bar crest, ratio of 

 depth-to-bar trough and depth-to-bar crest, distance between break point and 

 trough bottom, movement of mass center of bar, bar migration speed, bar 

 slopes, active profile height, step and terrace slopes, berm volume, berm 

 height, and berm slopes. This type of analysis is expected to stimulate 

 corresponding analysis of field profiles and provide guidance for collecting 

 analogous field data. 



539. Regression relationships were established between a number of 

 geometric characteristics of the profile and wave and sand properties. In 

 this process, the dimensionless fall speed H^/wT emerged as an important 



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