GRAVEL BEACH PROFILE EVOLUTION IN WAVE AND TIDAL ENVIRONMENTS

Mohamad Hidayat Jamal,Vanesa Magar,David J Simmonds

doi:10.9753/icce.v33.sediment.15

Mohamad Hidayat Jamal, Vanesa Magar + Show 1 more

Open Access

https://doi.org/10.9753/icce.v33.sediment.15

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Abstract

This paper reports progress made in modifying and applying the X-Beach code to predict and explain the observed behaviour of coarse grained beaches. In a previous study a comparison of beach profile evolution measured during large scale experiments under constant water level with numerical model simulations was made. This placed particular emphasis on the tendency for onshore transport and profile steepening during calm conditions (Jamal et al., 2010). The present paper extends that investigation to study the influence of the advection of surf processes induced by tidal water level variations effects, on gravel beach profile evolution. The parameter values and numerical model used in the simulation is similar to that presented previously. It is assumed that, to good approximation, the groundwater interface inside the beach follows the tidally modulated water level. The results obtained from the model shows that the model provides reasonable simulations of beach profile change in a tidal environment. In comparison with simulations under stationary water levels, a larger berm is produced in agreement with literature. Finally, good agreement is obtained between the model simulations and an example of field observations from a beach at Milford on Sea, UK. Further developments are outlined for future work.

Highlights

Interest in coarse grained, gravel and shingle beach environments and in the predicting of their dynamic behaviour in response to wave climate and water level variation has been increasing in recent years (Bradbury, 2000, Williams et al, 2012)
OF GRAVEL BEACH PROCESS AND MORPHOLOGY In order to predict the dynamic behaviour of gravel beaches, it is necessary to consider the complex balance of processes that controls the dynamics of the sediment
The present paper extends that investigation to study the influence of the advection of surf processes induced by tidal water level variations effects, on gravel beach profile evolution

Summary

INTRODUCTION

Gravel and shingle beach environments and in the predicting of their dynamic behaviour in response to wave climate and water level variation has been increasing in recent years (Bradbury, 2000, Williams et al, 2012). In the UK Gravel and shingle beaches form important natural coastal defence protecting substantial urban areas such as Southampton, which shelters behind Hurst spit, and designated habitats of scientific and interest and recreational value such as Chesil Beach. These beaches are associated with protection of items of key infrastructure such as Hinckley Point power station where understanding their response to extreme events affects more than calculations of flood risk. In this work we examine the adaptation and use of a public domain numerical model, X-beach (Roelvink et al, 2009 and van Thiel de Vries, 2009), based upon the non-linear shallow water equations, for capturing the 2-D profile dynamics of a gravel beach, through consideration of wave and tidal forcing, building on the work of Jamal et al (2010)

BACKGROUND

CONCLUSION