Influence of Underwater Bar Location on Cross-Shore Sediment Transport in the Coastal Zone

• Main Authors: Olga Kuznetsova, Yana Saprykina
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Journal of Marine Science and Engineering
• Subjects: coastal zone; storm deformations; underwater bar; XBeach; wave transformation; cross-shore sediment transport; equilibrium profile
• Online Access: https://www.mdpi.com/2077-1312/7/3/55

The effect of the underwater bar position on a sandy beach profile was studied on a timescale of one storm, using the XBeach numerical model. The largest shoreline regress occurred in the first hour of storm. For the chosen wave regime an underwater profile close to the theoretical Dean’s equilibrium profile is formed after 6 h. The position of the underwater bar affects the shoreline retreat rate. The lowest shore retreat occurs when the bar crest is located at a distance equal to 0.70⁻0.82 of the deep-water wavelength, corresponding to the period of the wave spectrum peak. The maximal shoreline retreat occurs when the bar is located at a distance that is close to a half wavelength. The shoreline recession depends on the heights of low-frequency waves. The smaller the mean wave period and the higher low-frequency waves’ height near the coast, the smaller the retreat of the shoreline. The distance of seaward sediment transfer is directly proportional to the significant wave height near shore.