(a) Case studies on NBCS implementation across varied coastal geomorphologies and hydroclimatic regimes, with evidence of long-term outcomes or monitoring data;
(b) Modelling studies that assess NBCS performance under future climate and sea-level rise scenarios;
(c) Innovations in field methods, remote sensing, and data integration for evaluating NBCS impacts on geomorphic and ecological processes;
(d) Systems-based approaches (e.g., coupled human–natural models, scenario planning) that address feedbacks between NBCS, coastal dynamics, and socioeconomic systems;
(e) Studies that focus on advancing the engineering design of NBCS and may include recommendations for types and values of design parameters and criteria;
(f) Perspectives on the institutional, regulatory, and financial frameworks shaping the deployment and long-term maintenance of NBCS.
We particularly (a) welcome interdisciplinary studies that combine geoscientific analysis with insights from ecology, engineering, planning, and policy, and (b) encourage dialogue on how transdisciplinary approaches can help guide the design, implementation, and long-term governance of effective NBCS.
Nature-based coastal solutions (NBCS) are increasingly recognized as effective, adaptable, and multifunctional approaches to mitigating coastal hazards while supporting ecological, economic, and social co-benefits. Despite a rapidly expanding evidence base, scaling of NBCS from localized interventions to regional, systems-level applications remains a fundamental challenge, particularly for long-term planning under accelerating sea-level scenarios, increasing storm intensity, and complex governance environments. This paper presents a comprehensive, interdisciplinary case study of Deer Island, Mississippi (USA), an Engineering With Nature® (EWN®) project that illustrates how integrated science, engineering, landscape architecture, and strategic partnerships can support the design, quantification, and implementation of NBCS at scale.
Deer Island represents a decade-long collaborative effort involving federal, state, academic, and non-profit partners working to stabilize eroding shorelines, restore degraded habitats, and strengthen the island’s overall geomorphic and ecological resilience. A central component of the project is an extensive data-collection program designed to quantify “as-is” island conditions and constrain uncertainty in future performance predictions. This includes topo-bathymetric surveys, sediment coring, vegetation mapping, and hydrodynamic and morphodynamic monitoring. All variations of work that build on the state-of-the-art techniques described in recent coastal resilience literature and research produced by the U.S. Army Corps' Engineering With Nature (EWN) research program. These datasets provide the empirical foundation for both the engineering design and the landscape architectural vision, ensuring that proposed nature-based features are grounded in site-specific processes.
Landscape architects worked alongside engineers and scientists to develop multifunctional NBCS designs that rebuild critical marsh, beach, and dune systems while enhancing habitat connectivity, recreational value, and long-term adaptability. These design concepts were translated into quantitative performance assessments using process-based numerical models that simulate storm surge attenuation, wave energy reduction, sediment transport, and morphological evolution under present and future climate scenarios. These modeling results demonstrate measurable risk-reduction benefits at both the island scale and the broader Mississippi Sound region, underscoring the importance of designing for system connectivity rather than isolated features.
A defining strength of this project is its collaborative, multi-sector governance structure. Regular engagement among engineers, ecologists, coastal managers, landscape architects, federal and state agencies, universities, and local stakeholders enabled iterative refinement of design alternatives, strengthened regulatory alignment, and ensured that both engineering and ecological performance criteria were jointly prioritized. This partnership-driven approach reduced institutional barriers, improved long-term maintenance planning, and provided a replicable model for other regions seeking to scale NBCS through coordinated decision-making.
Deer Island will has entered the construction phase and is marking a critical transition from concept to implementation, and will be monitored for years following. As one of the largest engineered NBCS efforts in America's Gulf waters, it demonstrates how integrated data collection, process-based modeling, and collaborative landscape-informed design can materially advance long-term resilience, reduce uncertainty, and provide transferable pathways for scaling NBCS across diverse environmental and governance contexts.
How to cite: Tritinger, A., Crisanti, S., Bailey, S., Berkowitz, J., Godsey, E., Suedel, B., and King, J.: Upscaling Nature-Based Coastal Solutions Through Integrated Design: Collaborative Data, Modeling, and Landscape Design for the Deer Island EWN Project, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-314, https://doi.org/10.5194/egusphere-egu26-314, 2026.
Saltmarshes provide numerous ecosystem services, contributing to climate change mitigation (carbon sequestration) and adaptation (coastal protection). While capable of accreting sediments in a dynamic equilibrium with changing sea levels, uncertainty remains regarding their continued resilience under accelerated rates of sea level rise (SLR). Ultimately, an improved understanding of how saltmarsh systems develop and evolve under changing conditions is needed to inform management and restoration strategies. Numerical frameworks that couple hydro-morphodynamics and vegetation dynamics (“eco-geomorphic” models) are emerging to support such advancements. Challenged by conflicts of scale and high computational costs, however, saltmarsh modelling studies often implement simplifications that ignore short-term vegetation dynamics such as seasonal growth cycles. Consequently, it remains poorly understood how seasonal variation impacts saltmarsh eco-geomorphic processes on sub-annual to multi-decadal timescales, and if there are implications for ecosystem vulnerability to SLR.
To address this, a numerical study was developed based on seasonal stem measurements of Sporobolus alterniflorus from the St. Lawrence Estuary (Québec, Canada). Coupling hydro-morphodynamics (TELEMAC-2D, GAIA) with a cellular automaton for vegetation dynamics, a novel eco-geomorphic framework was applied to simulate saltmarsh development under scenarios with explicit seasonal variation, versus vegetation properties averaged over the growing season. For each scenario, the model was used to simulate 180 years of eco-geomorphic development for an initially bare, idealized tidal domain.
This study demonstrates, for the first time, how sub-annual seasonal processes contribute to ecosystem development over the long-term (decades to centuries). Simulations that incorporated explicit seasonal variation in stem characteristics yielded more rapidly accreting saltmarsh platforms, with denser tidal channel networks; both supporting improved resilience under SLR. Sediment delivery to saltmarsh interiors was promoted during seasons of low biomass, while seasons of peak biomass strengthened flow routing around vegetation patches, enhancing channel network development. Identifying new mechanisms underlying long-term saltmarsh evolution and resilience, this work highlights the critical importance of integrating seasonality into eco-geomorphic models.
How to cite: Markov, A., Stolle, J., Temmerman, S., Gourgue, O., Nistor, I., and Pilechi, A.: Seasonal variation in stem morphology critically influences long-term saltmarsh development, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16146, https://doi.org/10.5194/egusphere-egu26-16146, 2026.
Saltmarsh habitat provides important ecosystem services such as water quality regulation, carbon sequestration, and flood defence. Marshes are also experiencing significant losses globally. One method of restoring saltmarsh habitat is the use of structures such as sedimentation fields to enclose areas of mudflat and encourage sediment deposition. Sedimentation fields offer opportunities for restoration in areas that are unsuitable for other, more common, restoration methods such as managed realignment. They can also provide protection for fixed engineered defence structures such as sea walls. However, sedimentation fields have predominantly been studied using numerical models or with a focus on vegetation colonisation. Therefore, it remains unknown whether the restored habitat can become self-sustaining through biophysical feedback processes accelerating vertical marsh buildup or whether there is a need for continued maintenance to prevent erosion of the deposited sediment.
This study presents findings from an empirical investigation of Rumney Great Wharf, Wales. Sedimentation fields were constructed here between 1989 and 2005, but since 2010 no maintenance has been carried out with fencing being eroded and lost. This allows for assessments of whether the restored area is self-sustaining or if continued maintenance is required. We show that 87% of the total area enclosed by sedimentation fields experienced erosion between May 2023 and 2024. This is despite sediment trap measurements indicating the potential for sediment to accrete at more than 9 cm/year. Trends in sedimentological processes are contextualised using depth, current velocity, wave action, and suspended sediment data. Our findings are evaluated in terms of the requirements for further research into sedimentary processes operating in sedimentation fields.
Using the insights gained from our study, we discuss the need to consider sedimentation fields as a continuation of human activity influencing natural processes, rather than the removal or reversal of the influence of prior human activity. We emphasise the need for transdisciplinary approaches to (i) develop further understanding of the interactions between physical and biological processes to enhance ecosystem functioning in sites restored using sedimentation fields, and (ii) to inform the design of future schemes. Further research is needed to fully justify the implementation of future sedimentation field construction, identify suitable locations for such schemes and inform their management, and to ensure such schemes provide a nature-based solution to coastal management challenges.
How to cite: Dale, J., Ladd, C., Kennedy, M., and Farrell, M.: Sedimentation fields: human activity, maintenance and the implications for successful saltmarsh restoration, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17431, https://doi.org/10.5194/egusphere-egu26-17431, 2026.
The analysis to be presented is focusing on the importance of the large historical regional variability and large recent temporal variability of mangrove processes along the Mekong Delta Coast. Such variability is insufficiently recognized in literature. Existing research and proposed solutions are often targeting specific provincial issues, presenting local not thoroughly tested solutions, and more importantly that are not generally applicable to other regions and sometimes even detrimental for other regions.
A thorough description is given of the longer-term differences in geography and physical processes, on centennial scales and on more recent, decade-scale human impacts on the various coastal regions of the Mekong Delta. For each of these regions, we present an analysis of the above-mentioned aspects, based on geological, historical, and recent observations of coastal evolution. Current physical process insights on mangrove dynamics are discussed, while including recent and expected impacts of human-induced and climatic change-induced impacts. A most pivotal finding is the quite recent occurrence of a tipping event causing the Mekong Deltaic Western Coast and parts of the Mekong Deltaic Eastern Coast turning to extreme erosion while having been stable over 100 years in the last century.
Our analysis aims to elucidate the profound geographical and temporal variability of coastal mangrove processes along the Mekong River Delta. This provides important information for new research studies that are welcomed strongly to support Vietnam in its quest to solve mangrove issues along the Mekong Delta Coast in a sustainable, nature-inspired manner. The Mekong Delta is of paramount national importance in an economic sense, and at least as important the delta is home to nearly 20 million inhabitants, who have their livelihood based on the coastal region.
How to cite: Phan, H. M., Stive, M. J. F., Phan, L. K., Truong, S. H., Dao, T. H., and Le, T. H.: On the importance of recognizing the large regional and temporal variability of coastal mangrove processes along the Mekong Deltaic Coast, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15854, https://doi.org/10.5194/egusphere-egu26-15854, 2026.
Mangroves help protect coastlines from storms in many regions around the world. However, less is known about how changing storm activities may influence this protection. Using global storm records and a transparent computer model, we examined how cyclone patterns have changed over recent decades. We found that between 1981–2000 and 2001–2020, mangrove exposure to cyclones increased by 13%. Importantly, the type of cyclones affecting mangroves has also changed: slow-moving cyclones have become much more common in the Caribbean, while fast-moving cyclones have increased in East Asia. These changes can affect how mangroves are damaged and how well they can continue to act as natural barriers against storms. Our findings highlight the need to consider changing storm behaviour when using mangroves as nature-based solutions for coastal protection under climate change.
How to cite: Mo, Y., Hall, J., Baldwin, A., Simard, M., and Donohue, I.: Mangroves as natural storm protection: How changing cyclones affect their role, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2801, https://doi.org/10.5194/egusphere-egu26-2801, 2026.
Salt marsh restoration can be considered an essential nature-based solution for coastal protection and climate change mitigation. However, restoration practices present a myriad of challenges, particularly in the journey from seed germination to achieving climate resilience, as response to challenges such as variable hydrology, and climate change impacts that can hinder seed establishment and growth. Effective restoration requires a deep understanding of the local ecology, the selection of native plant species, and adaptive management strategies to foster resilience against rising sea levels and shifting climate patterns. Active restoration is used less often than passive restoration, and involves improved seedling and planting techniques, with a drawback related to the physical damage done to healthy habitats through the collection of donor plants. A recent alternative solution to counter this destructive issue involves the installation of a plant nursery (mesocosms) for seed germination and plant production.
In this study, we present the experimental design and preliminary data on halophytes’ germination and seed propagation strategies, conducted in a mesocosm conditions. Our goal is to assess the optimal abiotic conditions to initiate the germination process of Atriplex Portucaloides seeds (mid-high marsh species), collected at Ria de Aveiro coastal lagoon (centre Portugal). Simultaneously, this study provides valuable insights into the climate resilience of Sporobolus maritimus (low marsh species) under increasing flood conditions, framed within various sea-level rise scenarios. Through fieldwork experiments at the Ria Formosa lagoon (south Portugal), data on the plant's adjustments to prolonged hydroperiods have been recorded. Adjustments in growth patterns and survival rates of Sporobolus maritimus are crucial for understanding the plant's response to environmental changes and provide essential information for estimating the longevity of restored populations. By addressing these two challenges, the obtained results enhance knowledge and support the development of effective restoration strategies to enhance the resilience of coastal salt marsh ecosystems against climate change.
Keywords: salt marshes, halophyte nursery infrastructure, sea-level rise, field experiment, resilience.
Acknowledgments: This study had the support of the Fundação para a Ciência e Tecnologia (FCT), through the strategic projects UID/00350/2025 (CIMA), UID/50017/2025 (doi.org/10.54499/UID/50017/2025) and LA/P/0094/2020 (doi.org/10.54499/LA/P/0094/2020) (CESAM- Centro de Estudos do Ambiente e do Mar). Inês Carneiro by was supported by the PhD grant 2024.02443.BD, also funded by the FCT. Thanks are also due to FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2030 and by Portuguese funds through FCT in the framework of the project COMPETE2030-FEDER-00929100 (BLUE-REWET).
How to cite: Carneiro, I., Sousa, A. I., Koppel, J. V. D., and Carrasco, A. R.: Challenges on salt marsh restoration: from seed to climate resilience, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-885, https://doi.org/10.5194/egusphere-egu26-885, 2026.
As climate change intensifies storm frequency and sea-level rise, global shorelines face increasing rates of erosion, threatening coastal ecosystems such as saltmarshes. Although saltmarshes are critical global assets for carbon sequestration and coastal defence, they are increasingly vulnerable to hydrodynamic stress. Conventional coastal engineering strategies to reduce erosion and maintain our coastal ecosystems often require significant capital and resource-intensive maintenance, driving an urgent need for lower-cost, nature-based solutions (NbS).
Driftwood, or Large Woody Debris (LWD), is a naturally occurring resource that is frequently removed from many coastal systems, despite its ecological benefits. While the use of LWD for sediment stabilisation and dune restoration has been documented in areas of Canada and New Zealand, many projects continue to face high failure rates. A significant disconnect exists between high-level policy support for these NbS and the lack of technical guidelines to ensure their success. Consequently, the potential for anchored LWD to serve as a permanent intervention in saltmarsh environments remains under-researched.
This project seeks to address the current lack of technical guidelines and the high rate of previous project failures by investigating the viability of anchored LWD as an NbS and restoration strategy. By evaluating the impact of these structures on morphodynamics and sediment stability, this research aims to standardise the application of anchored LWD, offering a scalable, cost-effective strategy to utilise debris as coastal defence.
How to cite: Twomey, A. and Goseberg, N.: From debris to defence: reclaiming driftwood's role on our shores, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19931, https://doi.org/10.5194/egusphere-egu26-19931, 2026.
In response to the challenges posed by coastal erosion and rising sea levels, bio-inspired strucutres represent an innovative solution by combining physical protection with ecological benefits. This study investigates how key structural parameters, including tortuosity, surface roughness, porosity, and structural diversity, affect near-bed shear stress and turbulence around bio-inspired coastal defense modules.
Wave flume experiments were conducted using fifty-one different modules, organized in three rows and tested under five monochromatic wave conditions (heights 2.5–10 cm, periods 1–2 s), scaled for Mediterranean deployment. Measurements from resistive wave gauges and Vectrino velocimeters were used to analyse wave energy dissipation, vertical current profiles, turbulence, and bed shear stress.
Preliminary results show that structural geometry appears to influence local hydrodynamics, with implications for a better understanding of how the selected parameters affect the surrounding hydrodynamic conditions. The effects of the parameters are ranked to guide the development of efficient, multifunctional, bio-inspired coastal defense solutions. A combination of several of these parameters, within a single module and then at the scale of an entire structure, allowed us to explore the potential benefits of structural complexity in coastal protection systems.
How to cite: Martinot, M., Meulé, S., Certain, R., Cognat, M., Beudin, A., Dalle, J., and Caceres-Euse, A.: Influence of structural parameters of Coastal Protections on near-bed shear stress and turbulence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21266, https://doi.org/10.5194/egusphere-egu26-21266, 2026.
Compound flooding in urban coastal areas is expected to become an increasingly costly problem due to projected sea-level rise throughout the 21st century. The emergence, and increasingly widespread acceptance, of “green infrastructure solutions” in recent years provides a wider range of adaptation measures compared to traditional gray infrastructure alone but comes with additional challenges. First, the impact of green infrastructure on flood risk is less straightforward to quantify relative to the augmentation of hard structures. Second, the net economic impact of green vs gray infrastructure in the form of flood reduction and associated ecosystem co-benefits is difficult to compare. Here we present a cost-benefit analysis of different sea-level rise adaptation options for Coos Bay, Oregon, U.S., which each incorporate different degrees of wetland restoration (green infrastructure) and levee heightening (gray infrastructure). For each scenario, continuous water level predictions are produced over the period 2020-2100 by pairing a physically constrained hybrid harmonic tidal water level model with stochastically modeled storm surges and a simplified wind wave runup model. Property damages and transportation delay costs are then calculated for each flooding event. This novel workflow produces temporally granular flood damage quantification which incorporates evolving hydrodynamic and meteorologic conditions. We hypothesize that wetland restoration will be cost-competitive with levee heightening once ecosystem services are financialized along with avoided flood losses.
How to cite: Zapp, S., Brand, M., Taofiq, Y., Bacopoulos, P., Diefenderfer, H., McKeon, M., Schmitt, J., and Janousek, C.: Economic comparison of sea-level rise adaptation solutions along the green-gray infrastructure continuum: a case study from an estuary on the U.S. Pacific Coast, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16049, https://doi.org/10.5194/egusphere-egu26-16049, 2026.
In January 2024, the state of Maine's, USA, coastline experienced multiple storms that caused extensive damage to public infrastructure and private property. The town of Wells, which encompasses the Webhannet and Ogunquit estuaries, suffered damage to “grey” coastal defenses, such as seawalls, bulkheads, and riprap, which were breached and therefore not able to protect roads and buildings. Failure of traditional defenses has partly motivated a growing interest in nature-based solutions, in addition to the range of ecosystem services these natural systems can provide, for enhancing protection along Maine’s coastline in areas where the adoption of such “green” solutions is feasible. Saltmarsh restoration, for example, is an approach that aims to bring back degraded ecological function of a tidal marsh, while simultaneously providing increased flood protection. In this study, we develop a LISFLOOD-FP model for the town of Wells using high-resolution (~1m) DEM and land cover datasets. We validate the model through satellite imagery such as Sentinel-2 data. We use the model to map the inundation extent in Wells during the January 10th coastal storm and to estimate flood exposure of the built environment. Next, we simulate the restoration of the tidal marsh within the two estuaries and assess its ability to reduce the flood footprint of the January 10th storm. To this end, we identify megapools suitable for drainage, thin layer placement, and revegetation, and therefore modify the model’s elevation and roughness coefficient in these targeted areas. Our study evaluates the effectiveness of pool-to-marsh restoration as a nature-based approach in decreasing flood depth and velocity near adjacent buildings and roads.
How to cite: Boumis, G., Hamidi, E., and Spencer, T. B.: Coastal flood impacts on the built environment in Wells, Maine: Assessing the effectiveness of pool-to-marsh restoration in reducing exposure, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-131, https://doi.org/10.5194/egusphere-egu26-131, 2026.
Currently, a substantial proportion of power stations, railway infrastructure, wastewater treatment facilities, and residential areas are at risk of coastal flooding, resulting in significant annual economic losses. Hard engineering solutions are becoming economically unviable due to the high costs of construction, maintenance, and adaptation to changes in sea level and storms.
For this reason, there is a growing interest in engineering with nature (including the creation of salt marshes, seagrass beds, beach nourishment, and mega-nourishment), which offers a more economically viable alternative and supports net zero-carbon emissions and local amenity value, as highlighted in the 25-year Government Plan to Improve the Environment and the FCERM strategies for England, Scotland, and Wales.
However, despite the growing recognition of the necessity to move towards this greener alternative for coastal protection, there is still limited guidance on the implementation of engineering with nature compared to hard engineering solutions. There are no quantitative and process-based decision-making tools or guidelines to aid engineers, planners, and governments in selecting coastal management strategies suited to their unique local environments. There remain many uncertainties regarding the conditions that maximize the establishment and longevity of engineering with nature, as well as uncertainties regarding its effectiveness.
The project ENARM develops novel understanding necessary to protect coastal infrastructure and coastal communities through the widespread adoption of engineering with nature. ENARM uses a novel combination of remote sensing, artificial intelligence, and computer models to provide, for the first time, design criteria for coastal protection using engineering with nature, as well as the knowledge necessary to select the most durable and efficient coastal management type and location.
Results are summarised into interactive decision-support tools, to enable a consistent evaluation of the pros and cons of different coastal management interventions, including uncertainties related to their effectiveness under different sea-level rise and storm scenarios.
How to cite: Leonardi, N.: Combining Artificial Intelligence, remote sensing and computer modelling for the design of Nature Based Solutions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7898, https://doi.org/10.5194/egusphere-egu26-7898, 2026.
The Oxford Marine Protection Project, in collaboration with WWF Philippines, is supporting community-based mangrove conservation in the Del Carmen Mangrove Forest in Siargao, recognised as the largest intact mangrove forest in the Philippines. We present an integrated framework combining on-ground assessments with novel satellite and geospatial datasets across four categories: habitat extent and condition, environmental stressors, biodiversity indicators (quantified using Bio-in-the-Box pipelines), and spatialised threat data, including evidence of illegal logging.
This multi-source approach is used to assess ecosystem vulnerability and co-benefits such as coastal protection and blue-carbon potential. The framework supports the identification of biodiversity hotspots, storm-resilient areas, degraded zones requiring restoration, and locations impacted by resource extraction. Our work demonstrates how integrated remote sensing and biodiversity data can strengthen the design, prioritisation, and long-term evaluation of nature-based coastal solutions in community-managed mangrove systems.
How to cite: Mukherjee, H.: Mangrove conservation in the Largest Mangrove Forest of Philippines - Integrating satellite data with community conservation efforts , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21594, https://doi.org/10.5194/egusphere-egu26-21594, 2026.
Enhancing Biodiversity Through Repurposing Manmade Structures with Secondary Coatsal Benefits
Authors: Henric Schmidt1, Nicoletta Leonardi1, Darryl Newport2, Andy Plater1,Stephen Roast3
Affiliation: 1University of Liverpool, UK; 2University of Suffolk, UK. 3 Sizewell C, UK.
The decommissioning of coastal nuclear power stations, such as the Magnox site at Sizewell A, offer a critical opportunity for coastal management. Traditionally, decommissioning involves the removal of large radioactive components making the decommissioning dangerous and expensive however, these degrading materials offer significant untapped value for boosting biodiversity in nearby marine environment by providing habitat for flora and fauna furthermore these artificial reefs are effective at reducing coastal erosion and providing flood protection. This research investigates the feasibility of repurposing decommissioned nuclear infrastructure to serve a dual purpose: reducing coastal erosion and providing flood protection through wave energy dissipation and enhancing marine biodiversity by providing shelter for marine life.
To accurately assess the feasibility of this project, this study employs a three-pronged methodological approach. First, Computational Fluid Dynamics (CFD) will be utilized to model various structural orientations and reef designs, identifying which configurations maximize both wave energy dissipation and the creation of low flow rate areas which are required to induce biodiversity. Second, on site visits and SCUBA dives at Sizewell A will be conducted to establish a current ecological baseline and assess the existing structural condition. Finally, findings from the digital models and field observations will be validated through laboratory emulation, using scaled physical models in a wave tank to test the most promising designs under controlled hydrodynamic conditions.
By integrating digital simulation, field observation, and physical experimentation, this research aims to bridge the gap between nuclear decommissioning and coastal engineering. The project seeks to provide a framework for the effective utilization of legacy concrete structures, such as those found at Sizewell A. Furthermore, this research will provide insights into "Design for Decommissioning," potentially influencing the structural design of future nuclear plants to facilitate repurposing for marine applications. Ultimately, this work aims to provide a scalable model for how the nuclear industry can contribute to a more sustainable and "nature-positive" future, transforming industrial liabilities into resilient ecological assets that also protect vulnerable coastlines.
How to cite: Schmidt, H.: Enhancing Biodiversity Through Repurposing Manmade Structures with Secondary Coatsal Benefits, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3937, https://doi.org/10.5194/egusphere-egu26-3937, 2026.
Climate change is continuing to affect coastal regions through rising global sea levels and evolving storm conditions, while land subsidence further amplifies relative sea-level rise in many low-lying areas. Coastal hazards arising from the combined effects of waves and high water levels are increasingly exposing areas to erosion and flooding. In this study, a low-lying region along the coast of Boundary Bay in British Columbia (BC), which is exposed to waves and storm surges, is studied. Communities and critical infrastructure in this region are protected from flooding by an existing 100-year-old dyke, which was not designed to account for sea-level rise. The “Living Dyke” is a pilot study implemented by the City of Surrey, BC, to assess and demonstrate the viability of nature-based infrastructure solutions to enhance coastal flood protection in the region. The project involves placing sediment and planting native salt marsh vegetation to test four stabilization techniques including brushwood dams, a sand berm, rock berm, and oyster-shell bags within the intertidal zone to attenuate waves and reduce wave overtopping of the dyke. In collaboration with biologists and ecologists, adaptive management, monitoring, replanting, and brushwood dam repair has occurred since construction in 2023. A series of in-situ pressure sensors have been deployed to monitor wave and water-level conditions at the field site. Using the observations, a high-resolution numerical model (XBeach) is calibrated, validated and applied to simulate storm events and flooding scenarios at the Living Dyke. Modelling of major wave events and sea-level rise scenarios is conducted to evaluate the performance of the different stabilization techniques. The results provide insight to the potential benefits of the Living Dyke as a nature-based technique to mitigate coastal squeeze and reduce the combined impacts of waves, storm surges, and sea-level rise. Ultimately, the interdisciplinary results integrate to provide the City of Surrey with guidance on the implementation of a field-scale nature-based infrastructure solution along the dyke.
How to cite: St. Marseille, M. M. J., Mulligan, R. P., Gauk, J., Murphy, E., and Provan, M.: Modelling combined wave and water-level hazards at a nature-based infrastructure site in British Columbia, Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13833, https://doi.org/10.5194/egusphere-egu26-13833, 2026.
Posters virtual: Wed, 6 May, 14:00–18:00 | vPoster spot 4
EGU26-2636 | ECS | Posters virtual | VPS32
Resilient Recovery: Financing Nature-based Coastal Solutions for Port Sudan’s Urban Infrastructure.Wed, 06 May, 14:12–14:15 (CEST) vPoster spot 4
Coastal cities in fragile and conflict-affected states face unprecedented challenges in maintaining infrastructure and protecting ecosystems. In Sudan, Port Sudan has recently emerged as the temporary administrative capital, experiencing rapid urban pressure alongside heightened climate vulnerability. This research evaluates the integration of Nature-based Coastal Solutions (NBCS), such as coral reef and mangrove preservation, into the city’s urban recovery framework. Utilizing GIS and satellite-based geoscience monitoring, the study assesses the current state of coastal assets and their protective capacity. A major barrier to implementing these solutions is the financing gap and high perceived risk in fragile economies. This study explores innovative financial frameworks, specifically the role of Development Finance Institutions (DFIs) in providing 'patient capital' and de-risking investments for sustainable coastal infrastructure. By combining interdisciplinary financial modeling with environmental assessment, the research proposes a strategic roadmap for financing resilient coastal protection. The findings demonstrate that NBCS can significantly reduce infrastructure restoration costs while serving as a vital catalyst for long-term economic stability and post-conflict recovery.
Final results, including a detailed comparative cost-benefit analysis and quantified financial projections, will be presented at the conference. This will provide a rigorous evidence-based framework for integrating Nature-based Solutions into Port Sudan’s post-conflict urban recovery.
How to cite: Ahmed, M.: Resilient Recovery: Financing Nature-based Coastal Solutions for Port Sudan’s Urban Infrastructure., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2636, https://doi.org/10.5194/egusphere-egu26-2636, 2026.
EGU26-1457 | ECS | Posters virtual | VPS32
Mangrove traits influencing coastal protection under varying environmental and eco-geomorphic conditions.Wed, 06 May, 14:15–14:18 (CEST) vPoster spot 4
Mangrove forests provide critical shoreline protection in tropical and sub-tropical regions through wave attenuation, soil accretion and floodwater storage. These protective mechanisms relate to both ecosystem functionality and persistence (Lovelock et al. 2024). Multiple studies over the past decades have effectively shown that mangrove forest extent can lead to reduced wave heights between 50-99%, with vegetative characteristics slowly being introduced as a critical element (McIvor et al. 2013). Increasing evidence has identified that the eco-geomorphological conditions shape the consistency and scale of protection but have not been properly considered. Ecological, hydrodynamic and geomorphological processes which occur at various temporal and spatial scales influence species-specific interactions, functional type formations and habitat structure (Gijsman et al. 2021). Mangrove forests can develop into distinct ecotypes over time (Twilley and Rivera-Monroy 2009), directly influenced by tidal exchanges between the mangrove forests and nearshore environments, affecting the level of productivity within the mangroves (Mitsch and Gosselink 2015). These interactions influence the mangrove forest structure through variability in sediment deposition rates, biomass accumulation, seedling recruitment and overall forest productivity (van Hespen et al. 2023).
Since variations in eco-geomorphological features affect mangrove functionality and persistence at multiple scales, this research will investigate how these differences can affect the ability of mangroves to provide consistent coastal protection. Building on existing modelling approaches (Beselly, van Der Wegen, and Roelvink 2025), the aim is to design an ideal model capable of capturing nuanced interactions between mangrove ecosystems and the geomorphological features. For instance, predictive models (WAPROMAN), designed to capture wave propagation through a uniform forest, utilised drag coefficients (McIvor et al. 2013), while a measure of mangrove forest extent seaward followed a mechanistic approach using the window of opportunity for seedling establishment predictions (van Hespen et al. 2023).
The current workflow will identify and isolate the key drivers and traits of crucial mangrove forests that affect mangrove functionality and persistence, for parameterisation. As a preliminary approach, these parameters will be integrated into a numerical model, incorporating elements from previous mechanistic and empirical approaches, modified to ascertain and accommodate the variability in mangrove eco-geomorphology and sediment dynamics (Gijsman et al. 2021). This process can facilitate the quantification of impact and identify key thresholds that these selected attributes of mangrove forests have on the function and persistence related to long-term coastal protection. Through this integration of multiple layers of eco-geomorphological variability, this work offers insights into how mangrove systems work as Nature-based Solutions and how they thrive within our changing climate.
How to cite: Emmanuel, S.: Mangrove traits influencing coastal protection under varying environmental and eco-geomorphic conditions. , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1457, https://doi.org/10.5194/egusphere-egu26-1457, 2026.
EGU26-1439 | ECS | Posters virtual | VPS32
Field Data Collection to Support the Numerical Modelling of Mangrove Contributions to Compound Flood MitigationWed, 06 May, 14:18–14:21 (CEST) vPoster spot 4
Small Island Developing States (SIDS) experience disproportionate vulnerability to natural and climate related hazards driven by geographic constraints, demographic trends, limited economic diversification and growing development pressures. In the Caribbean, flooding is one of the region’s most devastating and recurrent hazards, contributing to substantial socio-economic losses. Despite frequent events, many SIDS lack the long-term datasets needed to characterize flood behavior, particularly for coastal compound flooding, involving the interaction of multiple drivers such as storm surge, waves, tides, precipitation, runoff and river discharge. Climate change, including sea level rise, is expected to alter these processes and increase uncertainty in both magnitude and frequency.
Coastal ecosystems such as mangrove forests are increasingly recognized for their potential as Nature-based Coastal Solutions (NBCS), offering coastal protection alongside social, environmental and economic co-benefits. However, key gaps remain, including limited understanding of their flood mitigative properties across varying hydrodynamic conditions and stages of ecosystem maturity and health. Although numerical models are widely used to assess flood hazards, their ability to represent multiple interacting drivers and incorporate NBCS remains limited, a challenge that is particularly pronounced in data-sparse regions. Addressing these limitations requires field data to develop numerical models.
The relevance of these challenges becomes particularly clear in Trinidad’s South Oropouche River Basin (SORB), a low lying and highly flood prone watershed on the southwest coast that includes mangrove areas within the Godineau Swamp. This study therefore centers on collecting the necessary datasets and integrating them into the numerical modelling needed to characterize compound flooding in this basin. Field monitoring in SORB includes weather stations, water level loggers, short-term ADCP deployments, and a paired camera and water level logger system designed to capture flood depth and extent at a high resolution. Additional measurements including water quality parameters and vegetation characteristics from field surveys and satellite imagery, will support the mangrove related parameterization.
The modelling will be forced primarily using open-source datasets, with field observations used to assess their performance and suitability. Comparison of radar rainfall with in-situ measurements will enable the development of a bias-corrected relationship, allowing long-term radar datasets to be translated into site-specific rainfall inputs for compound flood modelling. These observations will be supplemented by historical datasets, including river discharge, Intensity–Duration–Frequency (IDF) curves, bathymetry and land cover. Thus, the numerical model will simulate the key hydrodynamic processes driving compound flooding while mangrove influences will be represented using vegetation-drag formulations to capture momentum dissipation and associated reductions in inundation. Field observations will be used to calibrate and validate the model, enabling spatial estimates of flood depth and extent under different forcing scenarios.
Field monitoring in SORB is expected to provide new insights into how flood drivers interact to generate inundation, as well as emerging trends and patterns, while deterministic modelling will quantify the degree to which mangroves mitigate flooding. Together, the data-collection and modelling approaches offer a practical means of improving compound flood assessment in regions with limited long-term observations and support a more holistic evaluation of NBCS for SIDS.
How to cite: Williams, A.: Field Data Collection to Support the Numerical Modelling of Mangrove Contributions to Compound Flood Mitigation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1439, https://doi.org/10.5194/egusphere-egu26-1439, 2026.
