Wave interaction of vertical seawalls fronted by shingle beaches

Investigating how waves interact with vertical walls when a mobile shingle beach is present in front of them
Pebble beach

Wave interaction of vertical seawalls fronted by shingle beaches

Investigating how waves interact with vertical walls when a mobile shingle beach is present in front of them
Title: Wave Interaction of Vertical Seawalls Fronted by Shingle Beaches
Funded by: °µÍø½âÃÜ ( postgraduate research studentships) and industry engagement through consultancy collaborations from and
Dates: October 2023 – September 2026
Project partners: and
°µÍø½âÃÜ staff: Mr Furkan Demir (PhD student), Professor Alison Raby (Director of Studies), Dr David Simmonds (Co-Advisor), Dr Martyn Hann (Co-Advisor)
Industry advisor:
 

Overview

Coastal communities increasingly rely on vertical seawalls for protection, yet many of these structures are fronted by dynamic shingle beaches that constantly reshape under wave action. This project investigates how waves interact with vertical walls when a mobile shingle beach is present in front of them. 
Through physical modelling in our COAST laboratory and advanced data analysis, the research examines wave overtopping, wave forces, and beach profile evolution. 
The aim is to improve prediction methods and provide more reliable guidance for coastal defence design under changing sea levels and storm conditions.

Objectives

  • Quantify wave overtopping at vertical walls fronted by shingle beaches under irregular wave conditions
  • Investigate how beach morphology influences wave loading and overtopping discharge
  • Evaluate and refine existing design guidance (e.g. EurOtop formulations) for composite coastal structures
  • Develop improved empirical relationships and reduction factors for engineering applications
  • Provide practical recommendations for safer and more resilient coastal infrastructure design.
Rough shingle simulated in a tank

Understanding how waves interact with both structures and beaches simultaneously is essential for designing coastal defences that are not only robust today, but resilient under future climate conditions.

Furkan DemirMr Furkan Demir

Context of the issue 

Many coastal towns rely on vertical seawalls for flood and erosion protection. However, these structures are often built in front of shingle beaches that are highly dynamic and respond rapidly to storms, tides, and changing sea levels. During extreme events, beach levels can lower significantly, increasing wave loading and overtopping at the wall. 
Existing design guidance largely treats the structure and the beach separately, which can lead to uncertainty in predicting overtopping and structural forces. With rising sea levels and more intense storm patterns, improving the understanding of this combined wave–beach–structure interaction is critical for resilient coastal infrastructure.
Sea wall simulated in a tank

How the project addresses the issue

This project combines physical modelling, detailed instrumentation, and advanced data analysis to investigate wave interaction with vertical seawalls fronted by mobile shingle beaches. 
By systematically testing irregular wave conditions and varying beach profiles in the COAST Laboratory, the research quantifies overtopping discharge, wave forces, and beach evolution. 
The results are used to evaluate and refine existing engineering prediction methods, helping to reduce uncertainty in coastal defence design. Ultimately, the project contributes towards more reliable, climate-resilient design approaches for composite coastal structures.
Sloping shingle beach simulated in tank

Centre for Coastal and Ocean Processes and Engineering (C-COPE)

C-COPE brings together strength areas from across the University's Faculty of Science and Engineering with a research focus on the physical and chemical processes in coastal, ocean and marine environments, and their human impacts.
The Centre's sphere of interest stretches from the head of tidal estuaries to the bottom of the ocean, and includes the disciplines of physical oceanography, marine biogeochemistry, coastal engineering and marine geology.
 
Tuvalu Tepuka atoll