Limits of Wave Runup and Corresponding Beach-Profile Change from Large-Scale Laboratory Data
UNIVERSITY OF SOUTH FLORIDA TAMPA DEPT OF GEOLOGY
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Thirty laboratory experiment SUPERTANK runs, including both erosional and accretionary wave conditions with random and monochromatic waves, were analyzed to examine wave runup and the corresponding upper limit of beach-profile change. The upper limit of beach change UL was found to approximately equal the vertical excursion of total wave runup, Rtw. An exception was runs where beach or dune scarps were produced, which substantially limit the uprush of swash motion to produce a much reduced total runup. The vertical extent of wave runup above mean water level on a beach without scarp formation was found to approximately equal the significant breaking wave height, Hbs. Therefore, a new and simple relation Rtw Hbs is proposed. This linear relationship is supported by a conceptual derivation. The relation is extended to UL Rtw Hbs to approximate the upper limit of beach change. This formula accurately reproduced the measured upper limit of beach change from the three-dimensional experiments in the Corps large-scale sediment transport facility. Predictions of wave runup were not improved by including a slope-dependent surf-similarity parameter. The limit of wave runup was substantially less for monochromatic waves than for random waves, attributed to absence of low-frequency motion.
- Physical and Dynamic Oceanography
- Hydrology, Limnology and Potamology