THE SIGNIFICANCE OF WAVE REFLECTION ON THE MORPHOLOGY OF INTERTIDAL MUDFLATS

Elizabeth Chellew,Carl Amos,Ian Townend,Kate Rossington,Stephen Richardson

doi:10.9753/icce.v32.sediment.50

Abstract

The influence of seawalls in modifying the equilibrium form of a shoreline has previously caused extensive debate. A numerical model was used to predict the equilibrium form of muddy intertidal profiles, along a shoreline in Southampton Water, UK. It was found that the profile containing a seawall had a very different profile form to the undefended sites, and that this seawall profile could not be accurately represented in the model. The model was extended to include wave reflection from the seawall, producing a new prediction with a much improved resemblance of the observed profile. It was concluded that the likely cause of the different profile form at the site of the seawall in this case, is due incident and reflected wave interaction.

Highlights

The effect of wave dissipation on the morphology of intertidal areas has been the topic of extensive study for both cohesive (Lee and Mehta 1997) and non-cohesive (Dean 1991) sediments
In this study we consider how an equilibrium form on a cohesive intertidal profile is altered by wave reflection and use a numerical model to predict the likely influence of a seawall
A marked difference was observed, between undefended and seawall profiles, for the data collected along a length of shoreline in Southampton Water

Summary

Introduction

The effect of wave dissipation on the morphology of intertidal areas has been the topic of extensive study for both cohesive (Lee and Mehta 1997) and non-cohesive (Dean 1991) sediments. Analytical and numerical models have been used to examine the equilibrium form of intertidal areas in response to tide and wave conditions (Fredrichs and Aubrey 1996; Roberts et al 2000). Wave reflection from a seawall, how it might modify the equilibrium form of shorelines, has caused extensive debate. In this study we consider how an equilibrium form on a cohesive intertidal profile is altered by wave reflection and use a numerical model to predict the likely influence of a seawall. Wave reflection causes an additional wave energy component acting on the mudflat surface, increasing the overall level of wave activity over the intertidal area

Results

Discussion

Conclusion