Numerical modeling of wave runup on steep and mildly sloping natural beaches

TitleNumerical modeling of wave runup on steep and mildly sloping natural beaches
Publication TypeJournal Article
Year of Publication2018
AuthorsFiedler J.W, Smit P.B, Brodie K.L, McNinch J., Guza RT
JournalCoastal Engineering
Date Published2018/01
Type of ArticleArticle
ISBN Number0378-3839
Accession NumberWOS:000418981000008
Keywordsefficient; gravel beaches; long waves; numerical modeling; parameterization; propagation; setup; swash; Total shoreline water level; Wave runup

Runup on ocean beaches includes steady wave setup and oscillating swash, often decomposed into wind generated sea-swell (SS), and lower frequency infragravity (IG) waves. We show that the numerically fast, open-source numerical model 1D SWASH predicts accurately the bulk properties of runup observed on two natural beaches (one steep and one shallow sloped) for a range of incident wave conditions. The runup tongue shape was measured with a scanning lidar, and the waterline location was defined in both the observations and model with a 10 cm depth threshold. Runup is reasonably accurately predicted with energetic (e.g. 5 m significant height) incident waves, even though the assumption of 1D bound waves significantly overpredicts infragravity energy at the offshore boundary in 10 in depth. The model-data comparisons are limited by statistical chatter, often larger in runup than offshore because runup energy is concentrated in the relatively narrow infragravity IG band with low effective degrees of freedom.

Short TitleCoast. Eng.
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