Wave Energy Attenuation Research Articles

An experimental study on wave transmission by engineered plain and enhanced oyster reefs

This study examines the interaction between random waves and an oyster reef, both in its plain state and when enhanced by energy dissipating macro-roughness. The investigation was carried out using wave flume experiments, incorporating different water levels and wave conditions. The primary focus of the study revolves around two key parameters: freeboard and wave steepness. Additionally, the study explores the influence of macro-roughness arrangement on the wave energy transmission. Empirical relationships were established to determine the wave transmission coefficient for both the plain reef and the reef enhanced by macro-roughness. These relationships highlight the significance of the relative freeboard and wave steepness for the plain oyster reef. Moreover, a correction factor was introduced to account for the impact of macro-roughness configuration on the wave transmission coefficient. The findings of this study suggest that the incorporation of macro-roughness can effectively attenuate wave energy through dissipation and reflection, thereby serving as an additional measure for wave energy mitigation through nature-based solutions.

Computational Parallel on Simulation of Wave Attenuation by Mangrove Forest

Coastal ecosystems, specifically mangrove trees, safeguard coastal regions against natural disasters like erosion, floods, and tsunamis. Numerical simulations employing the Shallow Water Equation (SWE), encompassing mass and momentum conservation equations, are used to comprehend how mangroves attenuate wave energy. The SWE incorporates Manning's friction term, which is directly influenced by mangrove forests. However, the SWE's complexity and sensitivity to initial conditions hinder analytical solutions. Despite its increasing computational demands, we utilize the robust staggered grid method to address this challenge. Our study examines mangroves' wave-attenuating effects and introduces a parallel computational model using OpenMP to expedite computations. Findings reveal that mangroves can reduce wave amplitudes by up to 33% when employing a Manning's coefficient of 0.3 within confined basin simulations. Furthermore, our parallel computing experiments demonstrate substantial computation speed enhancements; the speedup improves up to a point, with a notable 7.26-fold acceleration observed when utilizing eight threads compared to a single line. Moreover, more than a 10-fold acceleration is observed when the number of threads is greater than 16. This underscores the significance of parallelization in exploring mangrove contributions to coastal protection.

Field observations and long short-term memory modeling of spectral wave evolution at living shorelines in Chesapeake Bay, USA

Living shorelines as a nature-based solution for climate change adaptation were constructed in many places around the world. The success of this type of projects requires long-term monitoring for adaptive management. The paper presents a novel framework leveraging scientific machine learning methods for accurate and rapid prediction of long-term hydrodynamic forcing impacting living shorelines using short-term measurements of water levels and wind waves in the largest estuary in the U.S. Different from existing data-driven wave prediction models focusing on significant wave heights, this study is focused on the prediction of wave energy spectra in shallow water using winds and tides as the input feature and short-term measurements of wave spectra and water depths as the label. Long Short-Term Memory (LSTM) models were developed using four-month wave measurements in the stormy seasons to predict integral wave parameters and energy spectra for multiple years. The developed models accurately predicted wave heights, peak periods, and energy spectra around the living shorelines, capturing complex wave dynamics, such as wave generation by wind, nonlinear wave-wave interactions, and depth-limited wave breaking in the shallow water of a large estuary. The validated models were then used to determine the long-term wave forcing impacting the living shorelines based on the modeled wave characteristics and spectra. Model results show that the surrogate models utilizing LSTM to predict wave spectra in the frequency domain enable long-term predictions of spectral wave evolution with a minimal computational cost. Our findings provide valuable insights into the efficacy of living shorelines in attenuating wave energy and demonstrate the utility of this approach in assessing the effectiveness of such living shoreline structures.

Oysters' Integration on Submerged Breakwaters Offers New Adaptive Shoreline Protection in Low‐Energy Environments in the Face of Sea Level Rise

AbstractSea level rise (SLR) and increasing storm frequency threaten coastal environments. Engineering solutions such as breakwaters will become ineffective for wave attenuation and erosion control due to SLR. As a natural alternative, oysters create three‐dimensional, complex reef structures that attenuate wave energy and increase sedimentation rates. If coupled with breakwaters, oysters may maintain breakwaters' efficiency over time as they are expected to grow with SLR. Here, we measured bathymetric changes over 3 years (via GPS) and wave dampening due to four‐made intertidal breakwaters within a small cove of the Choptank River (MD, USA). Then, we modeled the coupling of such gray structures with oysters through Delft3D‐SWAN to evaluate the performances of such hybrid solutions on coastal protection, under future scenarios of SLR and climate change. Modeling hydrodynamic results showed a gradual reduction in wave attenuation due to SLR. However, when oysters were included in the modeling, wave dampening in 100 years was 75% and 60% greater than gray breakwaters, at high and low tides, respectively. Morphodynamic results showed increasing net export of sediment from the coast due to SLR. Oyster addition also provided shoreline protection and sediment retention in 100 years compared with the use of breakwaters alone, thanks to oysters' capability to grow with SLR. The coupling between oysters and breakwaters may represent a valuable and effective methodology to protect our coast over a changing climate and a rising sea, where optimal conditions for oyster survivability occur and are maintained over time.

Empirical formulas for predicting the energy attenuation behavior of primary stress waves in 1D composite chain of viscoelastic spheres

One-dimensional composite chain of viscoelastic spheres are potential candidates for novel impact buffers. Understanding the energy attenuation behavior of primary stress waves in the composite chain of viscoelastic spheres is the premise for high-performance impact buffers design. Although the current research included viscoelasticity into the motion equations of spheres, most of them were limited to homogeneous chains. Moreover, the models of discrete system could not give the explicit expressions of the key factors governing the energy attenuation of primary stress waves. The absence of explicit formulas for the key factors hindered efficient optimization design of impact buffers constructed by one-dimensional composite chain of viscoelastic spheres. In this study, empirical formulas for predicting the input amplitude, the attenuation coefficient of the contact force and the transmission coefficient at the interface were constructed. Multivariate nonlinear regression method and dimensional constraint were applied to ensure that all the empirical formulas only employ the impact velocity and the parameters of the used spheres as independent variables. Intermediate factor was introduced for individual key factor to evaluate the accuracy of the empirical formula. Though the groups of empirical formulas have degraded performance in the low range of the intermediate factors, their accuracy in quantitatively predicting the energy attenuation behavior of the stress waves in one-dimensional composite chain of viscoelastic spheres deserves satisfactory.

FIELD OBSERVATIONS AND MODELING OF BEACH CUSP EVOLUTION IN THE PRESENCE OF AN ARTIFICIAL VEGETATION PATCH

Vegetation has been shown to reduce beach erosion by attenuating wave energy and trapping sediments (Feagin et al., 2015). To date, most of the studies on erosion reduction by vegetation are either theoretical, numerical, or based on laboratory experiments. Field data that quantify the effectiveness of beach vegetation as a protective measure against erosion is sparse owing to the difficulty in conducting controlled field experiments (Feagin et al., 2015). To improve our understanding of wave-beach-vegetation interaction, we conducted a field experiment from September 19 to October 10, 2021, at the US Army Corps of Engineers’ Field Research Facility (FRF) in Duck, North Carolina, as part of DUNEX (DUring Nearshore Event eXperiment). For this experiment, we installed a patch of artificial vegetation in the swash zone, constructed out of materials with known mechanical properties, to test how beach vegetation attenuates wave energy and reduces erosion. It is to be noted that we used zipties to build our vegetation patch.

Water wave scattering by pair of porous barriers in the presence of a bottom-standing rectangular obstacle

ABSTRACT Oblique wave scattering by a pair of partially immersed porous barriers, placed (i) on one side of (Position I), (ii) just above (Position II) and (iii) on the two sides (Position III) of a thick rectangular bottom-standing rigid obstacle, is studied here. The mathematical formulation and solution procedure of the corresponding boundary value problem are discussed using Havelock's expansion and Galerkin's approximation technique. During the solution procedure, a set of first-kind Fredholm-type integral equations is solved approximately by choosing suitable basis functions (Chebyshev and Gegenbauer polynomials). To address the singularities of order half and one-third that appear at the submerged edges of the thin barriers and the corners of the thick obstacle, appropriate basis polynomials with suitable weight functions are chosen in Galerkin's approximation. The reflection and transmission coefficients, dissipating wave energy, and dimensionless wave force are computed for various values of different parameters and depicted graphically in quite a number of figures. The numerical results for some special cases are compared with those available in the literature and excellent agreement has seen to have been achieved thus validating the correctness of the numerical method presented here. Based on numerical results it is observed that Position III of the barriers is more effective than Position I and Position II in resisting wave loads on marine areas and attenuating wave energy.

Preliminary characterization on the dynamic mechanism of asphalt mixture under on-site vibratory compaction

Compaction is the final critical step in the construction of asphalt pavements, but the dynamic response of the mixtures at the particle scale and its correlation with the compaction degree have received limited in-depth investigations. Based on the SmartRock sensor technique, this study is aimed for this inadequacy and to further understand the interaction characteristics (e.g., rolling speed, vibration range and contact width) between the steel drums and pavement surface during compaction at the particle scale. Meanwhile, the dynamic responses (i.e., acceleration frequency and amplitude) of the aggregates in the asphalt mixture were comprehensively investigated to establish the correlation between the acceleration amplitude and compaction degree of pavement. According to the results, the vibrating drum shows a higher compaction effectiveness than the driving drum in the z-direction. The acceleration frequency reflects the energy attenuation of vibration waves during vibrational compaction, and the attenuation of vibration acceleration is normally distributed with the distance from the SmartRock. Lastly, an empirical relationship was developed between the maximum acceleration and pavement compaction degree and can be used to provide reasonable estimations for the in-situ density. The findings are expected to shed light on the compaction mechanism of asphalt pavement, and to provide a potential approach/basis for improving the on-site quality control and decision-making during compaction.

Roles of breaking and reflection in wave energy attenuation on the shoreface-nourished beach

Shoreface nourishments with the artificial sandbar are effective strategies to mitigate coastal erosions mainly by wave breaking and reflection. Thus, a better understanding of the contributions of breaking and reflection in wave energy loss is important for the prediction and description of the performance of the shoreface nourishment. Experiments are conducted in a wave flume, and data analysis is complemented with numerical simulations performed with a phase-resolving model. Both incident and reflected wave heights are well reproduced by the numerical model. The ratio of reflection to reflection-plus-breaking energy loss ranges from 4% to 11%, implying the dominant role of breaking-induced dissipation over reflection in present cases. The wave transmission coefficient decreases with the decrease in the bar crest depth and onshore implementation of the artificial sandbar. The trapezoidal artificial sandbar promotes an intense wave breaking over the berm width and is more effective in eliminating waves than the triangular artificial sandbar. Due to the erodible nature of the artificial sandbar, future works will consider the use of a hydro-morphological coupled approach to study the time-varying characteristics of wave breaking and reflection during morphological evolution.

Wave damping by giant kelp, Macrocystis pyrifera.

The increased likelihood and severity of storm events has brought into focus the role of coastal ecosystems in provision of shoreline protection by attenuating wave energy. Canopy-forming kelps, including giant kelp (Macrocystis pyrifera), are thought to provide this ecosystem service, but supporting data are extremely limited. Previous in situ examinations relied mostly on comparisons between nominally similar sites with and without kelp. Given that other factors (especially seafloor bathymetry and topographic features) often differ across sites, efforts to isolate the effects of kelp on wave energy propagation confront challenges. In particular, it can be difficult to distinguish wave energy dissipation attributable to kelp from frictional processes at the seabed that often covary with the presence of kelp. Here, we use an ecological transition from no kelp to a full forest, at a single site with static bathymetry, to resolve unambiguously the capacity of giant kelp to damp waves. We measured waves within and outside rocky reef habitat, in both the absence and the presence of giant kelp, at Marguerite Reef, Palos Verdes, CA, USA. Nested within a broader kelp restoration project, this site transitioned from a bare state to one supporting a fully formed forest (density of 8 stipes m-2). We quantified, as a function of incident wave conditions, the decline in wave energy flux attributable to the presence of kelp, as waves propagated from outside and into reef habitat. The kelp forest damped wave energy detectably, but to a modest extent. Interactions with the seabed alone reduced wave energy flux, on average, by 12 ± 1.4 % over 180 m of travel. The kelp forest induced an additional 7 ± 1.2 % decrease. Kelp-associated declines in wave energy flux were slightly greater for waves of longer periods and smaller wave heights. Macrocystis pyrifera forests have a limited, albeit measurable, capacity to enhance shoreline protection from nearshore waves. Expectations that giant kelp forests, whether extant or enhanced through restoration, have substantial impacts on wave-induced coastal erosion might require re-evaluation.

Pressure and frequency dependence of elastic moduli of fluid‐saturated dual‐porosity rocks

AbstractThe elastic moduli of subsurface rocks saturated with geofluid often depend on the wave frequency and confining pressure due to the wave‐induced fluid flow and their significant intrinsic compressibility. Therefore, the knowledge of the pressure‐dependent dispersion of elastic moduli is usually used in broad practical scenarios such as geofluid discrimination and in situ abnormal pressure detection. We propose a simple dual‐porosity model to describe the pressure and frequency dependence of elastic moduli of fluid‐saturated rocks. First, we follow the idea of the Shapiro dual‐porosity model to yield more accurate formulas for pressure‐dependent stiff porosity and crack porosity. Then the new formulas for stiff and crack porosities are utilized to express the bulk and shear moduli of dry rocks as a function of pressure. Further, the bulk and shear moduli of a modified frame (i.e. a rock skeleton with the dry stiff pores and fluid‐saturated cracks) are formulated with the pressure‐dependent elastic moduli of dry rock. In order to consider the wave energy attenuation induced by fluid in cracks, the frequency‐independent fluid modulus imbedded in the formulas for bulk and shear moduli of a modified frame is replaced with a frequency‐dependent one incorporating the effect of viscoelastic relaxation. The effective bulk and shear moduli of entire fluid‐saturated body can be computed by inserting the pressure‐dependent stiff porosity and elastic moduli of a modified frame into the Gassmann equation. Moreover, appropriate simplification is performed on the central equations in the case of low porosity and weak deformation of stiff pores to yield an approximate model. Modelling results show that the proposed model can reasonably account for the nonlinear variation of bulk and shear moduli with the elevating effective pressure and cautiously predict the wave dispersion and attenuation. We validate our model by comparing the predicted elastic moduli with the corresponding results given by Shapiro model–based equations and with the laboratory measurements of five different fluid‐saturated rock samples.

Numerical investigation of wave-induced flexible vegetation dynamics in 3D using a coupling between DualSPHysics and the FEA module of Project Chrono

Vegetation meadows in coastal waters are a key constituent of a future green defense package due to the ecosystem services they provide and the potential to attenuate wave energy. To numerically describe the vegetation dynamics under wave action, this paper presents a novel application of a numerical coupling for solving fluid–elastic structure interactions (FSI) problems involving ultra-thin elements in a 3-D environment. The extended two-way coupling employed in this work combines the mesh-free Smoothed Particle Hydrodynamics (SPH) method in the DualSPHysics code to solve the fluid flow, and the Finite Element Analysis (FEA) structural solver in Project Chrono to solve the structural dynamics. To represent the vegetation, a flexible structure based on the Euler–Bernoulli beam model is used. The beam element is embedded into the SPH domain using an envelope subdomain that is discretized using dummy boundary particles. As such, this dummy envelope serves as a decoupling interface for the geometrical properties of the structure, allowing for ultra-thin structures smaller than the initial inter-particle distance (dp). The numerical approach is validated against an experimental setup including a flexible blade swaying under the action of an oscillatory flow. The results demonstrate that the numerical model is able to resolve the wave–vegetation interaction problem. Furthermore, additional insights into the blade dynamics reveal that the swaying velocity increases linearly along the length, with the upper part swaying at a speed comparable to the fluid velocity while the stem remains relatively stationary. Additionally, the findings indicate that rigid vegetation experiences higher forces per unit length, and in systems with substantial swaying motion, energy dissipation predominantly occurs around the lower base of the vegetation.

The effect of docking defects on a metal-dielectric shielded waveguide in the EHF frequency range

Background. To improve the accuracy of navigation and radar systems, functional nodes of the EHF wavelength range are used. At the same time, an increase in the operating frequency increases the requirements for the accuracy of manufacturing and docking devices. Analysis of the propagation of electromagnetic waves, subject to the presence of defects in the waveguide paths, will allow determining sufficient manufacturing accuracy and evaluating physical processes in an irregular area. Aim. The aim of this work was to study the effect of sharp irregularities on the characteristics of the digital twin of a broadband shielded dielectric waveguide operating in the frequency range from 90 to 100 GHz. Methods. Using a numerical experiment, two variants of irregularity were investigated. They are presented in the form of displacement of sections of shielded dielectric waveguides in the vertical and horizontal planes. Results. According to the values of the transfer characteristic of the waveguide path, the regularities of the attenuation of the electromagnetic wave energy from the magnitude of the irregularity are revealed and the permissible manufacturing accuracy is proposed. Conclusion. To solve the problems of sewerage of weak signals, the authors recommend using a non-jointed manufacturing technology.

Conductivity-Controlled Polyvinylidene Fluoride Nanofiber Stack for Absorption-Dominant Electromagnetic Interference Shielding Materials.

This work presents a novel method for achieving lightweight electromagnetic interference (EMI) shielding materials with high EMI shielding effectiveness (SE) through absorption-dominant mechanisms, utilizing only organic polymer nanofibers (NFs). Instead of incorporating high-density fillers, the approach involves adjusting the concentrations of iron chloride in the NFs and subsequent vapor phase polymerization (VPP) to control the polymerization density of poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of polyvinylidene fluoride (PVDF) NFs. This process results in NF layers with varying conductivity, creating a conductivity gradient structure. The conductivity gradient structure of the NF layers significantly enhances absorptivity by reducing impedance mismatches between the shielding material and the surrounding air, as well as between different interlayers. This reduction in impedance mismatches allows for efficient dissipation of absorbed electromagnetic (EM) waves within the highly conductive NF layer. This improved absorptivity is also attributed to the attenuation of EM wave energy through multiple reflections and scattering within the NF pores. Moreover, the gradient structure of the NF layers promotes interfacial polarization, further contributing to the effective absorption of electromagnetic waves. As a result, a high absolute EMI SE (SSEt) of 12,390 dB·cm2 g-1 with low reflectivity (0.32) was achieved without compromising the lightweight and flexible properties.

Coastal wave-energy attenuation by artificial wooden fences deployed for mangrove restoration: an experimental study

By offering natural protection along offshore wetlands, mangroves play a crucial role in providing great ecological and economic benefits to local communities. However, mangroves are currently facing an increasing threat of decline worldwide due to widespread human activities and climate change. Recently, eco-friendly wooden fences have been deployed along eroded coasts for mangrove restoration projects, and these fences have the capability to attenuate incoming waves and strengthen sediment deposition in new habitats for mangrove colonization and persistence. However, the design and performance of the fences used can differ substantially among different projects; therefore, it is necessary to study the major factors affecting the wave dissipation performance of these fences and find out a more effective structural design. Thus, we focus on two distinct types of fences with and without porous infill to study the function of infill porosity and frame density, and physical experiments of waves transmission through the fences were carried out in a wave flume, in which nine wooden fences with varied infill porosities (0.60–0.90) and frame densities (0.40 and 0.70) were predetermined to measure the wave transmission, reflection, and wave dissipation. In total, 180 experimental runs were conducted under 18 wave conditions with different wave steepness. The results showed that the fence with a lower infill porosity appears to increase wave transmission coefficient that comes at a cost of a higher reflection coefficient and less wave-energy dissipation inside the fence, and the fence with the highest porosity infills (90%) is nearly equivalent to the fence without any infills but a dense frame in terms of wave damping performance. Moreover, the wave transmission through both fences with and without infill can be remarkably affected by incoming wave steepness. The outcome of the research is not only indicating the importance of the appropriate infill porosity in attenuating incoming waves but also guiding the design of mangrove restoration project in offshore wetlands.

Numerical model for interactions between shallow water wave and continuous submerged porous structures

Submerged porous breakwater in shallow estuarine environments is considered to have the potential to provide shoreline protection as well as offshore structures. The research aims to address how submerged porous structures can effectively attenuate wave energy in shallow waters. In this paper, the wave generation library waves2Foam is used to generate waves. A series of numerical experiments are conducted taking into account different physical parameters of porous structures and wave factors.

Refinement of three-layer model of a damaged human body for the case of changing the moisture of the banding material

The object of study is a three-layer model of a damaged human body. In the course of the study, it was found that the generally accepted three-layer model of a damaged human body is built, in particular, on the assumption that the characteristics of dressings remain unchanged over time. Therefore, the vast majority of modern research in the field of passive radiometry requires the removal of such materials from the human body during the measurement or considers their characteristics to be unchanged and insignificant. Questions of a possible change in the results of measuring the radiation of the human body due to the use of plaster casts of varying degrees of humidity remain almost unexplored. As a result of the study, the mathematical three-layer model of the damaged human body was refined. An element was introduced into the model that describes the dependence of the attenuation of radio wave energy on the relative humidity of the plaster cast. The refined model makes it possible to increase the accuracy of measuring the temperature of the human body, taking into account the time of applying a plaster cast to it. Unlike the existing ones, the proposed model is based on an experimental study that simulates the measurement of the radiation of a human body with a plaster cast of different degrees of humidity. To refine the model, the obtained experimental data were processed by regression analysis methods. The results of processing the experimental data made it possible to establish the specific type and value of the coefficients of the desired dependence. The use of the obtained results of the study proves the possibility of remote non-invasive express diagnostics of the state of the human body in the presence of plaster-gauze bandages. Providing such an opportunity allows disaster medicine workers to increase the ability to fulfill the so-called “golden hour rule”, as well as to clarify the requirements for a medical radiothermal mapping system

Geological age and environments shape reef habitat structure

AbstractAimHabitat complexity plays an important role in the structure and function of ecosystems worldwide. On coral reefs, habitat complexity influences ecosystem services such as harvestable fish biomass and attenuation of wave energy. Here, we test how three descriptors of surface complexity—rugosity, fractal dimension, and height range—trend with the geological age of reefs (0.2–5.1 million years old), depth (1–25 m), wave exposure (1–306 kW/m), coral cover (0–80%), and three habitat types (aggregated reef, rock and boulder, and pavement).LocationWe surveyed across 234 sites and 4 degrees of latitude in the eight main Hawaiian Islands.Time PeriodApril 2019 – July 2019.Major Taxa StudiedReef building corals.MethodsWe estimate three surface descriptors (rugosity, fractal dimension and height range) using structure‐from‐motion photogrammetry. We evaluate hypothesized relationships between these descriptors and geological reef age, depth, wave exposure, coral cover and reef habitat type using generalized linear models that account for survey design.ResultsThe rugosity of reef habitats decreased with geological reef age; fractal dimension (and coral cover) decreased with wave exposure; and height range decreased with depth. Variations in these patterns were explained by the different habitat types and the way they are formed over time. Nonetheless, the three surface descriptors were geometrically constrained across all habitat types, and so habitats occupied distinctly different regions of habitat complexity space.Main ConclusionsThis study showed how broad environmental characteristics influence the structural complexity of habitats, and therefore geodiversity, which is an important first step toward understanding the communities supported by these habitats and their ecosystem services.

Freeze–thaw process of soil between two piles as monitored by piezoelectric ceramic sensor

As the mechanical properties of soil are affected by the moisture content, diameter of soil particles, and the soil temperature, we used piezoelectric ceramic sensors to monitor the freeze–thaw cycle of different soils at different temperatures and different moisture content. By studying the energy attenuation of stress waves propagating in freezing–thawing soil, its mechanical strength was determined. The results showed that the duration of freeze–thaw process was related to soil type and initial water content. For the same water content and larger soil particle size, the received signal amplitude and energy are larger. For the same soil type and higher water content, the received signal amplitude and energy are stronger. This study provides a feasible monitoring method for infrastructure construction in areas with complex geological conditions, such as Qinghai-Tibet frozen soil.

The concept of land bridge marshes in the Mississippi River Delta and implications for coastal restoration

Louisiana has high coastal wetland loss rates due to natural processes such as subsidence and anthropogenic activities such as construction of river levees and dams, pervasive alteration of surface hydrology by local industries such as oil and gas, and navigation. With the exception of the Atchafalaya River discharge area, most of Louisiana's marsh coastline is retreating and coastal marshes are degrading. In the inactive degrading delta regions, there exists a previously uncharacterized landform referred to colloquially as coastal ‘land bridge’ marshes. Land bridge marshes are saline or brackish marshes fronting large estuarine bays or lakes with sufficient fetch and wave energy to supply high levels of resuspended sediments to the marsh surface. They are generally linear features that are oriented parallel to the coast and the shoreline front retreats landward due to erosion from wave energy. These marshes persist over time vertically due to input of resuspended sediments but are experiencing rapid edge erosion due to wave attack. Comparison of data from Louisiana's Coastal Reference Monitoring System (CRMS) sites show that land bridge marshes have a greater frequency of higher soil surface elevation and higher soil bulk density than non-land bridge marshes. Because land bridges are vertically stable relative to other coastal wetlands, identification of measures to sustain these landscape features is important. Simulations using MarshMorpho2D, a process-based reduced-complexity morphology model, suggest that protection barriers installed on the seaward side of land bridge marshes will attenuate wave energy and, thus, edge erosion. Shoreline protection that can reduce wave energy but still allow sediment input to marshes include living shorelines, rock barriers, and/or breakwaters. Periodic thin layer nourishment of the marsh surface may be necessary to help sustain vertical growth. Further, marsh creation projects directly landward of land bridge marshes may benefit from their protection from waves and as a source of sediment. Consideration of land bridge marshes as distinct marsh types in the State Master Plan and integrated modeling could help to identify measures to sustain these landscape features.