EXPERIMENTAL ANALYSIS OF EROSIVE COHESIVE COASTLINE MORPHOLOGY

Bastien Caplain,Vincent Regard,Frédéric Moulin,Dominique Astruc

doi:10.9753/icce.v32.sediment.53

Bastien Caplain, Vincent Regard + Show 2 more

Open Access

https://doi.org/10.9753/icce.v32.sediment.53

Copy DOI

Abstract

Laboratory experiments have been performed in a wave flume to investigate the coastal cliff recession under regular waves forcing. The different processes of the cliff erosion cycle are described and we focus on bottom evolution, which seem mostly depend on the surf similarity parameter Î¾. We observed steep planar (Î¾ > 0.7), gentle planar (0.5 < Î¾ < 0.7) and bared (Î¾ < 0.5) profiles. We noticed different sandbar dynamics including either steady or unsteady self-sustained oscillating states. Then we estimate the role of the self-organized material on the cliff recession rate. We show that the cliff erosion increases with the wave energy flux and is stronger for a gentle planar profile than for a bared profile of bottom morphology. However, the cliff recession rate as a function of the cliff height is not monotonic due to a different dynamics of bottom morphologies.

Highlights

The coastlines of the Earth are composed of about 80% of rocky coasts; these coasts are composed of either consolidated or unconsolidated rocks such as clay (Collins and Sitar, 2008)
The bottom morphology rapidly evolves to a bared profile and plunging breaking waves are observed
Coastal cliff erosion by regular waves has been investigated in an experimental wave flume

Summary

Introduction

The coastlines of the Earth are composed of about 80% of rocky coasts; these coasts are composed of either consolidated or unconsolidated rocks such as clay (Collins and Sitar, 2008). We will study the influence of the wave properties and sediment supply on cliff recession rate. Cliff erosion rate and sediment transport on the bottom are studied in function of incident wave energy, wave shape and cliff height. Bottom morphology The influence of the wave climate on the bottom morphology (Fig. 3) is studied in a series of experiments with a cliff height of 8 cm.

Results

Conclusion