Coastal Protection Research Articles

Surf zone hazards before and after a beach nourishment in Virginia, USA

Beach nourishment is the leading coastal protection technique in the United States to combat erosion, enhance resilience to storm surge, and maintain recreational value. Despite these benefits, anecdotal reports suggest that beach nourishments elevate the surf zone hazard to beach patrons by steepening the beach face and altering the shoreface morphology such that conditions are more favorable for rip current formation. This study analyzes lifeguard rescue reports collected on the United States Atlantic Coast before and after a 2019 beach nourishment in Virginia Beach, Virginia, to assess whether the nourishment was correlated with an increased hazard to beach patrons. The data indicate that regardless of nourishment status, rescues were most probable during periods of high rip current probability (moderate to large wave heights and low-obliquity wave angles), along with low water level. To formally quantify pre-versus post-nourishment hazards, the proportion of rescues observed in nourished versus unnourished beach zones was compared with bootstrapped distributions of the pre-nourishment rescue proportions. Although the proportion of rescues in the nourished section of the beach exceeds the pre-nourishment average, it is not outside the overall range of pre-nourishment values obtained by random resampling. Consequently, there is insufficient evidence to conclude that the existing coastal management beach nourishment strategy increased the hazard to beach patrons at Virginia Beach.

Performance of integrated FB and WEC for offshore floating solar photovoltaic farm considering the effect of hydroelasticity

The offshore floating solar photovoltaic (PV) farm deployed in the open sea could be subjected to large environmental loading due to waves or wakes from travelling ships. To reduce the motion of the solar farm, mitigation methods such as protection of the solar farm via floating breakwater (FB) could be deployed. The FB serves as a buffer between the floating farm and the incoming wave force, and as it attenuates the wave forces, this creates a sheltered zone on the leeward side of the FB. The energy generation from the solar farm could be further enhanced via the integration of attenuator-type wave energy converters (WEC) with the FB. This paper investigates the performance of the hybrid FB – WECs as a coastal protection structure cum wave energy extraction devices. The effect of FB on mitigating the hydroelastic response of the floating solar farm is investigated. Four types of FB, i.e., I-, L-, U- and BOX-shape FBs are considered and their effectiveness in wave attenuation under regular waves arriving from different directions are studied. In addition, due to the long structure length-to-wavelength ratio of the floating solar farm and FB, the hydroelastic response of the structures is taken into consideration.

Trapezoidal breakwater on reducing resonant wave amplitude on a rectangular basin

In this study, we delve into the effectiveness of trapezoidal breakwaters in mitigating resonance phenomena. The challenge at hand is to identify the optimal configuration capable of halting resonance. Employing Shallow Water Equations with a friction term to encapsulate the breakwater’s roughness, we analytically solve the model to determine the natural wave period. This period serves as the instigator of an unstoppable harmonic oscillation. Numerically, we use the Finite Volume Method on a Staggered Grid to simulate the model for several cases to pinpoint the infimum value of the natural wave period required to impede resonance phenomena. This research holds significance for those involved in coastal protection design, particularly in the context of trapezoidal breakwaters. The findings contribute to the effective reduction, rather than amplification, of wave height, thereby enhancing the reliability of such coastal protection structures.

Effect of open-area ratios on wave attenuation over a submerged reef breakwater: An experimental study

The reef-type submerged breakwater (RSB) has been implemented around the world to provide coastal protection and natural shelter and habitat for marine species at the same time. A series of laboratory experiments are conducted in a wave flume to study wave propagation and transmission over RSBs with the four open-area ratios of 0.047, 0.131, 0.257, and 0.560. The experimental results demonstrate that the RSB significantly alters the wave propagation characteristics. The RSBs with the open-area ratio of 0.047 and 0.131 reduce the wave height to ∼70%. The RSBs with the open-area ratio of 0.047 and 0.131 perform better in attenuating than those with the open-area ratio of 0.257, and 0.560. As the open-area ratio decreases, the transmission coefficient decreases, while the dissipation coefficient increases. An empirical formula is proposed to calculate the wave transmission coefficient as a function of the RSB open-area ratio and wave steepness under regular waves. A cubic empirical formula with one unknown is also proposed to relate the distance from RSB stoss face to wave breaking point and the open-area ratio. The present study is expected to optimize RSB design for coastal protection.

Modeling Rip Current Systems around Multiple Submerged Breakwaters

Multiple submerged breakwaters (MSBWs) are commonly used coastal protection structures due to their specific advantages over the emerged ones. Rip currents, as the inevitable natural hazard in the gaps of these constructions, are investigated numerically in the present study. A fully nonlinear mild-slope equation (NMSE) model possessing both fully nonlinear and fully dispersive properties is validated and adopted in the simulations. With four monochromatic wave conditions of different wave heights, periods and incidences representing low-energy, typical, storm and oblique waves tested, the flow patterns and the low-frequency oscillations of the rip currents are studied. For the convenience of risk assessment, the rip risk level is divided into three degrees according to the maximum rip flow speed. The effects of the configurations of the MSBWs on the rip current system as well as the rip risk level are examined, considering different breakwater widths, heights, forms, gap widths and gap numbers. Simulation results suggest that the cross-shore configurations of MSBWs influence the rip risk level by inducing different wave energy dissipations but the longshore configurations of MSBWs by changing flow field patterns.

Impact of a coastal protection measure on sandy-beach meiofauna at Ahrenshoop (Baltic Sea, Germany): results from metabarcoding and morphological approaches are similar

Sand nourishment is a common and often applied coastal protection measure along the beaches of the German Baltic Sea coast. At the tourist beach of Ahrenshoop, large-scale sand nourishments are completed every five years along a 4-km stretch. The nourishment in question was executed between the end of October 2021 and mid-February 2022. Meiofaunal communities at the beach-water interface were monitored at six stations before (September 2021) and for one year after the impact (March and September 2022, March 2023). To assess the effects of sand nourishment on meiofauna communities, two complementary approaches were employed: whole community metabarcoding and morphological determination and counting of the animals. Both methods produced consistent results regarding community response to disturbance and subsequent recovery. During the period from autumn 2021 to spring 2023, drastic changes in the composition of communities were observed. Directly after the impact, the taxa Acari and Annelida nearly disappeared, abundances of Copepoda decreased substantially, and Platyhelminthes increased notably. The fact that the studied beach held a low diversity may have facilitated that metabarcoding and morphological determination followed the same trend. After initial studies comprising both methods, efficient assessments using only metabarcoding may be considered for comparable sites and situations.

Interrelationship between Wall and Beach Erosion in Loc An, Vietnam: Remote Sensing and Numerical Modeling Approaches

Beach erosion and coastal protection are complex and interconnected phenomena that have a substantial impact on coastal environments worldwide. Among the various coastal protection measures, seawalls have been widely implemented to mitigate erosion and protect coastal assets. However, the interrelationship between beach erosion and seawalls remains a critical topic for investigation to ensure effective and sustainable coastal management strategies. Seawalls impact the shoreline, particularly through the “end effect”, where the seawall functions similarly to a groin, causing erosion on the downdrift side relative to the direction of wave approach. This study provides a detailed analysis of the interplay between beach erosion and seawall structures in Loc An, Vietnam, employing both remote sensing and numerical approaches. Sentinel-2 images were employed together with an analytical solution to observe the shoreline change at the Loc An sand spit and to determine input values for the numerical model. Based on the shoreline dynamics, a numerical scheme was employed to study the shoreline evolution after the construction of a seawall. Our findings show that the shoreline evolution can be divided into three stages: (1) The first stage corresponds to the elongation of the sand spit without interference from coastal structures. (2) The second stage shows the effect of jetties on the shoreline, as signaled by the buildup of sand updrift of the jetties. (3) The third stage shows the effectiveness of the seawall, where the shoreline reaches its equilibrium condition. The study provides a quick and simple method for estimating shoreline diffusivity (ε) in situations where measured data is scarce.

Physical model analysis of stability coefficient for tetrapod innovation

Beach protection is vital to reduce the damage to shorelines and coastal areas; one of the artificial protections that can be utilized is the tetrapod. However, much damage occurred when using a traditional tetrapod due to the lack of stability coefficient (KD). Therefore, this research aims to increase the stability coefficient by providing minor modifications to the cape of the tetrapod, such as round-caped or cube-caped. The modification seeks to hold the drag force from the wave and offer a good interlocking in between the tetrapod. This research applied physical model test research using a breakwater model made from the proposed innovative tetrapod with numerous variations in dimensions and layers simulated with several scenarios. The analysis was carried out by graphing the relationship between the parameters of the measurement results and the relationship between dimensionless parameters, such as wave steepness H/gT2, and other essential parameters, such as the KD stability number and the level of damage in %. The result shows that the modified and innovative tetrapod has a more excellent KD value than the conventional tetrapod. In addition, the innovative tetrapod with the cube-shaped has a recommended KD value greater than the round shape. This means that for the modified tetrapod structure and the same level of security, the required weight of the tetrapod with the cube cap will be lighter than the tetrapod with the round cap. These findings have significant practical implications for coastal protection and engineering, potentially leading to more efficient and cost-effective solutions.

Multi-Fidelity Learned Emulator for Waves and Porous Coastal Structures Interaction Modelling

A thorough understanding and treatment of wave-structure interaction (WSI) mechanics is essential for the rigorous engineering design of coastal protections. Conventional numerical analysis methods are accurate and generalize well, but are heavily dependent on the adopted mesh resolution and frequently incur substantial computational costs. To bypass these limitations, a meshless multi-fidelity residual neural network (MRNN) emulator is introduced in this study to infer the spatio-temporal responses arising from WSI. MRNN first employs a ‘low-fidelity’ simulator to learn basic WSI relationships by training on simulations obtained using a coarse numerical mesh. Subsequently, a ‘high-fidelity’ (HF) simulator is then employed to learn the mapping between numerical simulations performed using the coarse mesh and additional detailed fine meshes. The results indicate that MRNN is a highly robust emulator which requires significantly less HF data through its hierarchical framework compared to conventional single-fidelity data-driven strategies. By way of example, the MRNN emulator is applied to the cases of a porous dam break and breakwater. A broad spectrum of WSI responses, such as water through the porous dam medium, can be accurately captured using the MRNN emulator which is benchmarked against a conventional numerical modelling with a fine mesh. The computational efficiency of the MRNN is shown to be independent of the mesh resolution and complexity of the studied partial differential equations. It provides a generic and utilitarian emulator for any engineering problem of interest.

Optimal design and placement of a combined trench and submerged breakwater system on the coastal area of Aceh

Tsunami waves are currently one of the most devastating water hazards that threaten regions or countries near the subduction zones, including Indonesia. In this research, a novel coastal protection system combining a submerged breakwater and a trench is proposed to mitigate tsunami occurrences. The model is developed based on the Shallow Water Equations, which are then solved analytically using the Separation Variables Method, and numerically using the Staggered Finite Volume Method. The wave transmission coefficient, which indicates the wave reduction rate generated by the system, is expected to be the outcome of both approaches. The numerical scheme is validated against the analytical solutions to verify its accuracy in estimating wave reduction by the system. Further, an optimization technique is integrated into the model to obtain the optimal size and position of each structure (submerged breakwater and trench) on the real bathymetry of Aceh's coast, which has been impacted by a deadly tsunami occurrence before. The results of this study are expected to be useful in the future development of coastal protection systems against tsunami waves, especially in Indonesia.

Beyond annual metrics: Linking seasonal population dynamics to vertical oyster reef growth.

Oysters are ecosystem engineering species building reef-like biogenic structures in temperate shallow water environments, serving as biodiversity hotspots. Recently, also their ecosystem services such as fish nursery, pollutants sink and self-sustaining coastal protection mechanisms came into a research focus. In light of accelerated sea level rise and increasing environmental dynamics, a determination of vertical growth rates of these biosedimentary structures is paramount in assessing their resilience. This study embarked on a comprehensive survey of seasonal vertical reef growth rates using terrestrial laser scanning and related population dynamics of two intertidal reefs built by the non-native oyster Magallana gigas in the Wadden Sea. We quantified median reef growth at 19.8 mm yr-1 for the Kaiserbalje reef and 17.5 mm yr-1 for the Nordland reef. Additionally, we tested the hypothesis that the seasonal variations in reef growth rates correspond to the local population dynamics, mainly the parameters of shell length and abundance which mirror delayed effects from previous spawning events. Shell growth rates were 0.03-0.06 mm d-1 in winter and 0.10-0.16 mm d-1 in summer, mean oyster abundance from autumn 2019 to spring 2022 was 627 ± 43 ind. m-2 and 338 ± 87 ind. m-2 at the Kaiserbalje and Nordland reefs respectively. Minor reef growth in the topmost reef area reflects an emerging equilibrium of the vertical reef position to actual sea level. Our findings are in accordance with growth of natural Crassostrea virginica reefs on the US East Coast, indicating potential resilience to actual and predicted sea level rise scenarios. Moreover, understanding local hydro-morphodynamic feedback linked to sea level rise will be vital in predicting the three-dimensional stability of these biosedimentary structures and habitats.

Application of gradient boosting machine in satellite-derived bathymetry using Sentinel-2 data for accurate water depth estimation in coastal environments

Accurate water depth estimation is crucial in coastal environmental management, resource exploration, and ecological protection. Traditional water depth measurement methods are often time-consuming and costly, especially in vast sea areas where their application is limited. However, with the rapid development of remote sensing technology, particularly the widespread use of high-resolution satellite imagery, water depth remote sensing has emerged as a more efficient, economical, and widely applicable solution. In this study, we utilized Sentinel-2 satellite data and applied various algorithms to accurately estimate water depth in the Nanshan Port area. The results showed that the Gradient Boosting Machine (GBM) model excelled in monitoring shallow water and coastal environments, effectively addressing challenges such as light attenuation and water scattering in turbid waters. Compared to traditional methods, GBM-generated predictions were smoother and more detailed. This study not only demonstrates the significant potential of satellite remote sensing for water depth measurement but also points to future directions for algorithm optimization and the integration of remote sensing technologies. It is expected to bring revolutionary progress to oceanic scientific research and coastal management.

Establishing patterns of change in the coefficients of reflection, transmission, and dissipation of wave energy depending on parameters of a permeable vertical wall

The object of research is permeable vertical walls (breakwaters) with different degrees of permeability. This paper reports the results of experimental research into the interaction of gravity waves with models of permeable vertical walls (breakwaters), which were formed from cylindrical piles of circular cross-section. With the help of visual and instrumental studies, the features of interaction of surface gravity waves with permeable vertical walls of different permeability have been identified. The degree of wave transformation by these walls was also determined in the form of reflection, transmission, and dissipation coefficients of wave energy. It was established that with a decrease in the permeability of the vertical wall and an increase in the steepness of the initial wave and a decrease in its period, the height of the reflected wave increased. The pattern of the transmitted wave height had the opposite trend. It was determined that the wave reflection coefficient increased with a decrease in the permeability of the vertical wall and the steepness of the initial wave. The wave transmission coefficient had the opposite trend, namely, it increased with increasing wall permeability and with decreasing steepness of the initial wave. The gravity wave energy dissipation coefficient decreased with increasing vertical wall permeability, but for waves with a significant steepness hi/λ>0.038, a decrease in the wave energy dissipation coefficient was observed for walls with low permeability and the appearance of extreme values of this coefficient. Thus, features in the interaction of surface gravity waves with permeable vertical walls (breakwaters) of different permeability have been researched and the degree of wave transformation by these walls has been determined, which could make it possible to effectively design and operate permeable vertical walls as coastal protection structures

Shifting sands: The influence of coral reefs on shoreline erosion from short-term storm protection to long-term disequilibrium

Climate change is exacerbating shoreline erosion and flooding, posing significant risks to coastal communities. Although traditional coastal defenses such as seawalls, dykes, and breakwaters offer protection from these hazards, their high environmental and economic costs are driving interest in cost-competitive nature-based solutions. Coral reef restoration is a nature-based solution that may be particularly apt to mitigate tropical coastal flooding and shoreline erosion while providing benefits to local tourism, fisheries, and nature. However, the novelty of this field requires studies demonstrating the benefits of reefs for coastal protection. While the flood protection benefits of reefs have been well-documented, their effects on shoreline erosion are comparatively less understood. Here, we investigate the effects of coral reefs on shoreline erosion by comparing tropical beach responses at short and long timescales, as well as identifying important reef structural features influencing coastal erosion rates. Our analyses leveraged two key datasets created in this study: the first derived from a literature review on short-term shoreline erosion due to storm events, and another compiling >80 years of long-term erosion rates, bathymetry, habitat, and wave energy for the Hawaiian Islands of Kauaʻi, Oʻahu, and Maui. Our analyses reveal three key findings regarding the effects of reefs on shoreline erosion. Firstly, we find evidence for the role of reefs in mitigating shoreline erosion during storm events, with coral reef-protected beaches experiencing 97 % less beach volume loss than unprotected beaches. Secondly, a linear regression analysis demonstrates that coral reef structure and wave energy are important predictors of long-term shoreline erosion rates, explaining 34 % of the variation across the Hawaiian Islands. Consistent with prior research, we find beaches protected by coral reefs with shallow reef crests, wide reef flats, calmer offshore conditions, and positioned farther from the shore exhibit lower erosion rates than others. Finally, when comparing historical erosion rates of protected and unprotected beaches in Hawai'i, we find a seemingly incongruous pattern where coral reef-protected beaches eroded up to 2x faster than beaches without reefs. While the cause of the enhanced erosion is yet to be fully understood, a combination of coral reef structural degradation and sea-level rise is likely shifting the equilibrium profiles of reef-protected beaches inshore. These results emphasize the role of coral reefs in reducing coastal erosion during storm events while revealing contrasting erosion patterns over long timescales. Future studies would ideally broaden the scope to include various regions, utilize advanced sediment transport models, and undertake field experiments to deepen our understanding of coral reef-coupled shoreline dynamics.

Roughness Ecosystem-based Approach to Estimate the Exposure Area of Tsunami on a Coastal City: A Case Study in Bengkulu City, Indonesia

Bengkulu City, as the main activity center in Bengkulu Province, is experiencing significant population growth. However, geographically, the city is vulnerable to tsunami disasters. High population growth outside the line with coastal area management also increases the risk of tsunami disasters in Bengkulu City due to green land conversion into built-up land. This condition is exacerbated by coastal abrasion that threatens the coastline, brings residential settlements closer to the shoreline, and conflicts over spatial utilization of the coastal green belt. Therefore, implementing tsunami mitigation measures, mainly through coastal ecosystem-based strategies, is crucial. This study compares the spatial modeling of tsunami inundation in Bengkulu City with three roughness scenarios of coastal vegetation: coastal forest and mangrove. These scenarios include a scenario without coastal vegetation, a scenario based on existing conditions, and a scenario with optimized coastal vegetation. Spatial modeling was conducted using cost distance analysis modeling to calculate the effectiveness of coastal vegetation in reducing tsunamis. The results showed that coastal forests and mangroves in existing conditions could effectively reduce tsunamis by 3.84% compared to land cover without coastal forests and mangroves. The coastal vegetation optimization scenario has effectively reduced the exposure area by 5.00% compared to that without vegetation. The coastal vegetation optimization scenario also has an effectiveness of 1.20% compared to the existing condition. The findings underscore the critical role of coastal vegetation as a natural barrier against tsunamis and emphasize the potential advantages of optimizing land cover to improve coastal protection.

Prediction of the impact of sea level rise in coastal areas where the tide embankments have been constructed

After the Great East Japan Earthquake in 2011, the Japanese government reconstructed coastal protection facilities to mitigate extreme disasters and coastal erosion. However, the substantial compression of coastal zones poses a challenge in coping with sea level rise, while maintaining a sustainable coastal ecosystem. To clarify the impact of environmental factors and sea level rise on coastal ecosystems in highly developed regions, this study integrated field surveys, geo-detector analysis, and coastal inundation models into the research framework. It explored the relationship between environmental factors and vegetation patterns and predicted the inundation areas and vegetation survivorship of 12 transects in the study area from 2030 to 2150. The results indicated that the distance from the tide embankment (DTE) and elevation (DEM) were the main driving factors, and the combination of the potential of hydrogen (pH) and DTE had a major impact on vegetation coverage. Notably, the distribution of vegetation was positively correlated with the width of the coastal zone, and when the width was less than 60 m, vegetation could not survive. With sea level rise, almost no vegetation will survive until 2150. Appropriate coastal width and height are conducive to maintaining the sustainability of coastal ecosystems.

Effectiveness of regional risk mitigation policies in equitably improving connectivity to essential service during hurricane-induced floods

This study aimed to evaluate the effectiveness of regional disaster mitigation policies in providing equitable access to essential services during hurricane-induced floods in Southeast Louisiana. Studies have been conducted on access to essential service facilities during and after disasters. However, there is limited research on whether current regional disaster mitigation plans ensure equitable access to emergency facilities. To this end, a methodology was developed to assess the effect of the 2017 Louisiana Coastal Master Plan developed by the Coastal Protection and Restoration Agency (CPRA) on equity in connectivity to essential service facilities (hospitals and fire stations) in a case study region in southeastern Louisiana. First, a graph-based model was used to represent the road network and determine the connectivity of five demographic groups during hurricane-induced flood scenarios. Herein, a hurricane-induced flood scenario with a low return period (50 years) was chosen for future years up to 2065, considering sea level rise and subsidence. Roads with flood depths exceeding 30 cm were considered impassable and were removed from the network. Connectivity was then determined using breadth-first search. Monte Carlo simulations were performed to propagate uncertainties in flood depths. It was found that minority groups were at a higher risk of losing access to emergency services during the selected hazard scenario. Native American and Asian populations were found to be at the highest risk of disconnection, followed by the Hispanic and African-American populations. Overall, the coastal master plan did not affect the equity (or lack thereof) in connectivity to essential service facilities.

Doing nothing is no solution: Coastal erosion management in Guardamar del Segura (Spain)

Human activities like dam construction in rivers and urban development in coastal areas, combined with climate change, are degrading coastal systems. As a result, many European countries have implemented laws and strategies to protect their shorelines. This research focuses on Guardamar del Segura in Spain, where human actions in the Segura River basin and changes in wave patterns have significantly damaged the beach-dune system, with erosion rates reaching −0.71 m/year. If these rates and extreme climate events continue to rise, the shoreline will keep retreating, leading to the destruction of beachfront houses and parts of the dune surface by 2050. This will cause changes in land ownership and irreversible ecological damage to the natural ecosystem. The Spanish Public Administration's inaction on coastal protection is due to a lack of coordination between government levels, insufficient technical tools to combat erosion, and inadequate legal mechanisms to fund protective measures. In contrast, countries like Germany, the Netherlands, and the United Kingdom have effective models in place. Potential solutions for Guardamar del Segura include beach and dune restoration or adding sand through revetments. Another option is a managed retreat of the most vulnerable buildings to avoid continuous repair and maintenance costs. Coastal erosion is a growing issue, and preserving our coastal ecosystems requires proactive measures, so doing nothing is no solution.

Laboratory study on effect of vegetation in reducing wave overtopping under wind effect

Understanding and mitigating wave overtopping are crucial for hinterland safety, yet research primarily focuses on designing coastal structures, with limited attention to structural materials. As global warming intensifies coastal hazards, there is a growing need for resilient infrastructures. A hybrid infrastructure incorporating vegetation alongside concrete may offer a viable solution. In this study, we evaluated the effect of vegetation on wave overtopping reduction under strong winds through hydraulic model experiments simulating extreme storm conditions. The experiments were conducted under the simultaneous action of wind, waves, and vegetation using a two-dimensional wind tunnel flume and vegetation. A higher vegetation density was found to exponentially reduce the overtopping rate. Moreover, dense vegetation was demonstrated to be equivalent to raising the height of protective structures by at least 1.1 m. Furthermore, the increase in overtopping rate by the effects of wind can be compensated by the reduction effects of vegetation. Based on these investigations, an equation was proposed to predict the wave overtopping rate that considers the effects of both wind and vegetation. The results highlight the potential applicability of vegetated coastal protection in future coastal disaster prevention against extreme events with stronger winds and waves that may be induced by climate change.

Modeling wave dynamics with coastal vegetation using a smoothed particle hydrodynamics porous flow model

Coastal vegetation serves as an effective nature-based solution for protecting shorelines from erosion and storm surges. A detailed understanding of the dynamic interactions between waves and vegetation is crucial for quantifying the mitigation potential of coastal vegetation during extreme climatic events. This study investigates wave dynamic interactions with coastal vegetation by developing a numerical model using the weakly compressible Smoothed Particle Hydrodynamics (WCSPH) method. The model simulates the effects of vegetation by incorporating vegetation porosity, drag, and inertia forces into the momentum equations. By integrating porosity information at specific background points, the SPH interpolation method effectively treats the interfaces between fluid and vegetation regions, allowing versatility in modeling various vegetation layouts without explicitly simulating their solid structures, which is computationally prohibitive. The numerical model is validated using laboratory-based measurements and analytical models for both submerged and emergent scenarios involving cylindrical and strip-type vegetation. The model is then utilized to investigate the effects of vegetation as both a natural line of defense and a retrofitting solution in front of a sea dike, to quantify the performance of nature-based solutions for enhancing climate resilience in natural and hybrid coastal protection infrastructures. The results reveal that canopy density significantly impacts solitary wave run-up and energy dissipation. For the configurations tested in this study, high-density vegetation reduces normalized wave run-up by 52% compared to simulations without vegetation, while low-density vegetation achieves a 17% reduction. These findings demonstrate the potential of vegetation, particularly at higher densities, to mitigate solitary wave energy and reduce run-up hazards. Furthermore, simulation results indicate that using vegetation as a retrofitting solution effectively mitigates overtopping rates, achieving a 37% reduction with minimal forest density (∅ = 0.023). These results underscore the effectiveness of nature-based interventions in enhancing coastal protection and resilience.