Numerical modelling of the erosion of marsh boundaries due to wave impact

Bendoni, Michele; Georgiou, Ioannis Y.; Roelvink, Dano; Oumeraci, Hocine

doi:10.1016/j.coastaleng.2019.103514

Cited by 25 publications

(12 citation statements)

References 59 publications

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“…Model water depth was defined at 2.5 m above 0 m bathymetry, such that the entire marsh surface was inundated, though at depths dependent on bathymetry, representative of a major storm surge or high tide event (Figure 1J). Vegetated cells were defined (Table 1) using values consistent with Bendoni et al (2019) using the default Dalrymple vegetation module (Dalrymple et al, 1984). The vegetation drag coefficient was chosen to be representative of the synthesis of both Anderson and Smith (2014) and Vuik et al (2016).…”

Section: Model Setupmentioning

confidence: 99%

How Much Marsh Restoration Is Enough to Deliver Wave Attenuation Coastal Protection Benefits?

et al. 2022

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As coastal communities grow more vulnerable to sea-level rise and increased storminess, communities have turned to nature-based solutions to bolster coastal resilience and protection. Marshes have significant wave attenuation properties and can play an important role in coastal protection for many communities. Many restoration projects seek to maximize this ecosystem service but how much marsh restoration is enough to deliver measurable coastal protection benefits is still unknown. This question is critical to guiding assessments of cost effectiveness and for funding, implementation, and optimizing of marsh restoration for risk reduction projects. This study uses SWAN model simulations to determine empirical relationships between wave attenuation and marsh vegetation. The model runs consider several different common marsh morphologies (including systems with channels, ponds, and fringing mudflats), vegetation placement, and simulated storm intensity. Up to a 95% reduction in wave energy is seen at as low as 50% vegetation cover. Although these empirical relationships between vegetative cover and wave attenuation provide essential insight for marsh restoration, it is also important to factor in lifespan estimates of restored marshes when making overall restoration decisions. The results of this study are important for coastal practitioners and managers seeking performance goals and metrics for marsh restoration, enhancement, and creation.

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Section: Model Setupmentioning

confidence: 99%

How Much Marsh Restoration Is Enough to Deliver Wave Attenuation Coastal Protection Benefits?

et al. 2022

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“…No process-based description is implemented to describe the formation of vertical cliffs at the dune foot undermining the dune slope with subsequent geotechnical failures of the dune slope that results in slumps of sand on the beach that can be taken away by the waves. For this marshes, Bendoni et al (2019) implemented a hydromorphodynamic interaction model in XBeach (Roelvink et al, 2009) to evaluate erosion of marsh boundaries due to wave impact. Although this study is limited to the cohesive sediments' environment, soil reinforcement due to roots has been modeled, which might be extended to other environments in the future.…”

Section: Toward An Integrated Model Of the Plant-sand Feedbacks The Integration Of Vegetation-dune Feedbacks In Existing Process-based Momentioning

confidence: 99%

Biomorphogenic Feedbacks and the Spatial Organization of a Dominant Grass Steer Dune Development

et al. 2021

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Nature-based solutions to mitigate the impact of future climate change depend on restoring biological diversity and natural processes. Coastal foredunes represent the most important natural flood barriers along coastlines worldwide, but their area has been squeezed dramatically because of a continuing urbanization of coastlines, especially in Europe. Dune development is steered by the development of vegetation in interaction with sand fluxes from the beach. Marram grass (Calamagrostis arenaria, formerly Ammophila arenaria) is the main dune building species along most European coasts, but also in other continents where the species was introduced. Engineering of coastal dunes, for instance by building dunes in front of dikes, needs to be based on a solid understanding of the species’ interactions with the environment. Only quantitative approaches enable the further development of mechanistic models and coastal management strategies that encapsulate these biomorphogenic interactions. We here provide a quantitative review of the main biotic and physical interactions that affect marram grass performance, their interactions with sand fluxes and how they eventually shape dune development. Our review highlights that the species’ spatial organization is central to dune development. We further demonstrate this importance by means of remote sensing and a mechanistic model and provide an outlook for further research on the use of coastal dunes as a nature-based solution for coastal protection.

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“…The model was introduced by Roelvink et al [9] in response to the 2004 and 2005 hurricane seasons in the U.S.A. Since then, it has been extensively used and validated in a variety of coastal settings, including saltmarshes [32,33], sandy, barrier coasts [5,34], sandy coasts defended by hard engineering structures [11] and coral reefs [35,36]. Early efforts to apply XBeach to gravel settings were made by Jamal et al [24] and Williams et al [37] but do not explicitly resolve wave runup from incident waves.…”

Section: Modeling Approachmentioning

confidence: 99%

Modeling Impact of Intertidal Foreshore Evolution on Gravel Barrier Erosion and Wave Runup with XBeach-X

Phillips

Brown

Plater

2020

JMSE

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This paper provides a sensitivity analysis around how characterizing sandy, intertidal foreshore evolution in XBeach-X impacts on wave runup and morphological change of a vulnerable, composite gravel beach. The study is motivated by a need for confidence in storm-impact modeling outputs to inform coastal management policy for composite beaches worldwide. First, the model is run with the sandy settings applied to capture changes in the intertidal foreshore, with the gravel barrier assigned as a non-erodible surface. Model runs were then repeated with the gravel settings applied to obtain wave runup and erosion of the barrier crest, updating the intertidal foreshore from the previous model outputs every 5, 10 and 15 min, and comparing this with a temporally static foreshore. Results show that the scenario with no foreshore evolution led to the highest wave runup and barrier erosion. The applied foreshore evolution setting update is shown to be a large control on the distribution of freeboard values indicative of overwash hazard and barrier erosion by causing an increase (with 5 min foreshore updates applied) or a decrease (with no applied foreshore updating) in the Iribarren number. Therefore, the sandy, intertidal component should not be neglected in gravel barrier modeling applications given the risk of over- or under-predicting the wave runup and barrier erosion.

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Numerical modelling of the erosion of marsh boundaries due to wave impact

Cited by 25 publications

References 59 publications

How Much Marsh Restoration Is Enough to Deliver Wave Attenuation Coastal Protection Benefits?

How Much Marsh Restoration Is Enough to Deliver Wave Attenuation Coastal Protection Benefits?

Biomorphogenic Feedbacks and the Spatial Organization of a Dominant Grass Steer Dune Development

Modeling Impact of Intertidal Foreshore Evolution on Gravel Barrier Erosion and Wave Runup with XBeach-X

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