Overtopping over Vertical Walls with Storm Walls on Steep Foreshores

As sea levels rise and extreme weather events become more frequent due to climate change, coastal urban areas are increasingly vulnerable to wave overtopping and flooding. Retrofitting existing vertical seawalls with retreated storm walls represents a key adaptive strategy, especially in the Mediter...

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Main Authors: Damjan Bujak, Nino Krvavica, Goran Lončar, Dalibor Carević
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Journal of Marine Science and Engineering
Subjects:
Online Access:https://www.mdpi.com/2077-1312/13/7/1285
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author Damjan Bujak
Nino Krvavica
Goran Lončar
Dalibor Carević
author_facet Damjan Bujak
Nino Krvavica
Goran Lončar
Dalibor Carević
author_sort Damjan Bujak
collection DOAJ
description As sea levels rise and extreme weather events become more frequent due to climate change, coastal urban areas are increasingly vulnerable to wave overtopping and flooding. Retrofitting existing vertical seawalls with retreated storm walls represents a key adaptive strategy, especially in the Mediterranean, where steep foreshores and limited public space constrain conventional coastal defenses. This study investigates the effectiveness of storm walls in reducing wave overtopping on vertical walls with steep foreshores (1:7 to 1:10) through high-fidelity numerical simulations using the SWASH model. A comprehensive parametric study, involving 450 test cases, was conducted using Latin Hypercube Sampling to explore the influence of geometric and hydrodynamic variables on overtopping rate. Model validation against Eurotop/CLASH physical data demonstrated strong agreement (<i>r</i> = 0.96), confirming the reliability of SWASH for such applications. Key findings indicate that longer promenades (<i>Gc</i>) and reduced impulsiveness of the wave conditions reduce overtopping. A new empirical reduction factor, calibrated for integration into the Eurotop overtopping equation for plain vertical walls, is proposed based on dimensionless promenade width and water depth. The modified empirical model shows strong predictive performance (<i>r</i> = 0.94) against SWASH-calculated overtopping rates. This work highlights the practical value of integrating storm walls into urban seawall design and offers engineers a validated tool for enhancing coastal resilience. Future research should extend the framework to other superstructure adaptations, such as parapets or stilling basins, to further improve flood protection in the face of climate change.
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spelling doaj-art-fffc69781b0e414092e893011bd344d22025-08-20T02:45:42ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-06-01137128510.3390/jmse13071285Overtopping over Vertical Walls with Storm Walls on Steep ForeshoresDamjan Bujak0Nino Krvavica1Goran Lončar2Dalibor Carević3Faculty of Civil Engineering, University of Zagreb, Fra Andrije Kačića-Miošića 26, 10000 Zagreb, CroatiaFaculty of Civil Engineering, University of Rijeka, Trg braće Mažuranića 10, 51000 Rijeka, CroatiaFaculty of Civil Engineering, University of Zagreb, Fra Andrije Kačića-Miošića 26, 10000 Zagreb, CroatiaFaculty of Civil Engineering, University of Zagreb, Fra Andrije Kačića-Miošića 26, 10000 Zagreb, CroatiaAs sea levels rise and extreme weather events become more frequent due to climate change, coastal urban areas are increasingly vulnerable to wave overtopping and flooding. Retrofitting existing vertical seawalls with retreated storm walls represents a key adaptive strategy, especially in the Mediterranean, where steep foreshores and limited public space constrain conventional coastal defenses. This study investigates the effectiveness of storm walls in reducing wave overtopping on vertical walls with steep foreshores (1:7 to 1:10) through high-fidelity numerical simulations using the SWASH model. A comprehensive parametric study, involving 450 test cases, was conducted using Latin Hypercube Sampling to explore the influence of geometric and hydrodynamic variables on overtopping rate. Model validation against Eurotop/CLASH physical data demonstrated strong agreement (<i>r</i> = 0.96), confirming the reliability of SWASH for such applications. Key findings indicate that longer promenades (<i>Gc</i>) and reduced impulsiveness of the wave conditions reduce overtopping. A new empirical reduction factor, calibrated for integration into the Eurotop overtopping equation for plain vertical walls, is proposed based on dimensionless promenade width and water depth. The modified empirical model shows strong predictive performance (<i>r</i> = 0.94) against SWASH-calculated overtopping rates. This work highlights the practical value of integrating storm walls into urban seawall design and offers engineers a validated tool for enhancing coastal resilience. Future research should extend the framework to other superstructure adaptations, such as parapets or stilling basins, to further improve flood protection in the face of climate change.https://www.mdpi.com/2077-1312/13/7/1285wave overtoppingstorm wallsvertical seawallsSWASH modelingcoastal adaptation
spellingShingle Damjan Bujak
Nino Krvavica
Goran Lončar
Dalibor Carević
Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
Journal of Marine Science and Engineering
wave overtopping
storm walls
vertical seawalls
SWASH modeling
coastal adaptation
title Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
title_full Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
title_fullStr Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
title_full_unstemmed Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
title_short Overtopping over Vertical Walls with Storm Walls on Steep Foreshores
title_sort overtopping over vertical walls with storm walls on steep foreshores
topic wave overtopping
storm walls
vertical seawalls
SWASH modeling
coastal adaptation
url https://www.mdpi.com/2077-1312/13/7/1285
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