Depth of Closure Determination in the Vicinity of Coastal Structure

Abstract

This study is conducted to analyze the effect of coastal structure to depth of closure variation. Analysis on time series bathymetry data has been applied to determine location of depth of closure. The deviation of bathymetry profile changing is also considered. Furthermore, longshore variation of depth of closure is proposed. The hydrodynamic conditions are simulated using Boussinesq model derived by Peregrine (1967). This model is applied considering its applicability to observe non-linear and dispersion phenomenon while wave propagates to the shoreline. The simulation is carried out under regular wave assumption with 20% wave height in deep area is applied as representative wave. The simulation results are obtained in term of surface water level, bottom velocity in x and y direction and current velocity. The result is utilized to calculate maximum bottom velocity just outside boundary layer. To observe sediment movement along the coast, maximum shear stress is calculated under wave-current combined motion. Dimensionless Shields parameter is also assessed. The simulation results are depicted in spatial map. Furthermore, the effect of coastal structure to depth of closure variation is confirmed using hydrodynamic conditions.

Observation of Rapid Seabed Erosion Near Closure Depth During a Storm Period at Hujeong Beach, South Korea

“…The accuracy of d c would depend on the quality as well as quantity of the data, and the estimated value of d c could increase if the duration of the observation increased (Capobianco et al, ; Hinton & Nicholls, ). In addition to its variation according to the time scale, d c could vary in space as well; there have been reports about its longshore variations (Gracia et al, ; Różyński et al, ; Widyaningtias & Kanayama, ).…”

Serious Erosion of the Southern Sendai Coast Due to the 2011 Tohoku Earthquake Tsunami and Its Recovery Process

“…15.1 and 15.4 ). It should be noted that the closure depth due to storm waves is reported to be 8 m or 15 m (Widyaningtias et al 2013 ) and the depth due to the tsunami was deeper than that due to storm waves. Deposition with a width of more than 0.5 km expanded in the longshore direction in Area C and D where the water depth was between 5 and 15 m, whereas deposition expands in the narrower and shallower area in Area A.…”