Tips for a superior coastal natural infrastructure project

– Water hydrodynamics and coastal engineering are essential areas of civil and environmental engineering that deal with understanding and controlling the behaviour of water bodies, particularly in coastal areas. Coastal areas are active environments which are shaped by intricate interactions among waves, tides, currents, and sediment transport. With the increased rate of climate change leading to sea-level rise and the occurrence of extreme weather events, there is a growing need for sophisticated hydrodynamic modeling and robust coastal infrastructure. This seminar discusses the basic principles of water hydrodynamics, such as fluid motion, wave generation and propagation, tidal dynamics, and their contribution to coastal processes. It emphasizes recent developments in coastal engineering in the form of numerical modeling of nearshore currents, methods for coastal erosion control, breakwater design, and beach nourishment planning. The focus is on the integration of high-resolution computational fluid dynamics (CFD), remote sensing, and Al-assisted prediction tools to simulate and manage coastal hazards. Examples of recent global coastal projects between 2020 and 2025 are presented in case studies, highlighting novel designs combining ecological sustainability and engineering effectiveness. Policy implications, strategies for disaster mitigation, and interdisciplinary cooperation in safeguarding vulnerable coastal areas are also touched upon by the seminar. With greater insight into hydrodynamics and engineering interventions, the discipline is striving to secure the long term sustainability of coastlines and coastal infrastructure. Key Words: Hydrodynamics, coastal engineering, wave modeling, sediment transport, erosion control, climate resilience, CFD, coastal infrastructure

Coastal systems are sensitive to direct and indirect impacts of climate change. Approximately 90% of all coastal areas will be affected by climate change to varying degrees. Nearly half of the world's major cities are located within 50 km of a coast, and coastal population densities are 2.6 times greater than those of inland areas, with a steep rise over the years. While coastal critical infrastructure is expanding, more social and physical systems are increasingly exposed to climate-induced hazards. The interconnectedness and interdependencies of critical infrastructure systems increase their systemic instability and fragility, resulting in greater dynamic risk and cascading impacts. Coastal critical infrastructure systems on several continents are at risk from the effects of climate change, including sea level rise, storm surges, and extreme weather events. Therefore, it is necessary to build and run climate-resilient infrastructure that is planned, designed, implemented, and operated to predict, be prepared for, and adapt to changing climatic circumstances. This review provides an up-to-date, objective, and critical assessment based on the literature to help determine what is known and what needs the future attention of researchers.

Successful adaptation strategies need to be underpinned by strong legal and regulatory frameworks. Whilst there are many legal fields that will be impacted by the need to adapt to climate change, this Chapter presents select examples of international, regional and national legal and regulatory instruments that may be considered relevant for the assessment of climate change impacts/risks and the development of adaptation measures for coastal transport infrastructure.

Accurately estimating the return values of significant wave height is essential for marine and coastal infrastructure, particularly as climate change intensifies the frequency and intensity of extreme wave events. Traditional models, which assume stationarity in wave data, often underestimate future risks by neglecting the impacts of climate change on wave dynamics. Combining time series decomposition and recurrence analysis, the research develops a nonstationary framework to predict significant wave height. The stochastic component is modelled using a stationary probability distribution, while the deterministic component is predicted based on sea surface temperature projections from CMIP6 climate scenarios. The model evaluation demonstrates strong predictive capability for both stochastic and deterministic components. Application of the model to China’s coastal waters reveals significant discrepancies between stationary and nonstationary return value estimates. Compared to conventional distribution models, the nonstationary model predicts substantial increases in extreme wave heights. These findings underscore the importance of adopting nonstationary models to more accurately assess future risks posed by extreme wave events in a changing climate.

Climate change is anticipated to have a significant impact on coastal infrastructure, including navigational aids and ports. This paper presents the results of a vulnerability assessment of ports in Australia to climate change. Results reveal variable vulnerability in ports in the short and long term in relation to their exposure to climate change. However, this is offset by inherent adaptive capacity both in current climate change initiatives driven by ports, and in the self-confidence of the industry to be able to adapt. We conclude with a reflection on the implications of these results for future ports analyses.

Climate changes and coastal development pose growing risks to coastal roadways constructed on flat and low-elevation terrains near retreating shorelines. Although GIS has been widely used for shoreline change analysis and roadway management, significant limitations remain in accurately analyzing shoreline changes relative to roadways and integrating the analysis results into roadway spatial databases in the Geographic Information System (GIS). In this regard, this study proposes a novel geospatial approach that integrates the linear referencing system (LRS) with the vector-offset based analysis method for shoreline change. The LRS, implemented in GIS, defines the specific positions of a roadway using relative distances from predefined referents. Vector offsets, representing the shortest distance and direction from historical shorelines to the roadway, are then employed to analyze shoreline changes. The proposed approach was applied to a coastal roadway experiencing significant shoreline changes driven by climate change and the construction of coastal infrastructure. The results demonstrate the effectiveness of the proposed approach in analyzing shoreline retreat caused by coastal infrastructure development, as well as shoreline accretion following the installation of erosion control structures. These results, which closely reflect the actual erosion pattern, indicate that the proposed approach can effectively support planning for roadway maintenance and reinforcement.

This paper explores the lessons learnt from the Optimising Adaptation Investment projects for the Department of Climate Change and Energy Efficiency–it includes coastal settlements, water supply and rail infrastructure case studies. These projects are the first of their kind in Australia and are considered internationally as a leading example of economic cost benefit analysis. They have been used effectively to inform decision making on specific adaptation responses to climate change risks to existing and new infrastructure. The lessons learnt will be explored for offshore platforms, ports, rail, road, drainage, tailings dams, mine facilities, water, and power supply, which includes the following elements: What decision makers require to make informed decisions under the uncertainty of climate change impacts. Reducing the uncertainty through economic modelling and cost benefit analysis. Optimising the right timing and scale of various adaptation options. Benefiting from oil and gas infrastructure adaptation opportunities. To further support the elements above, the applied process for integrating climate adaptation into infrastructure planning, design and operation will be illustrated by AECOM project experiences. AECOM has completed more than 60 significant climate change risk and adaptation projects for mines, ports, water supply and treatment, energy generation, transmission and distribution, rail, road, and coastal settlements in Australia, including the report: Climate Change Impacts to Infrastructure in Australia for the Garnaut Climate Change Review.

Worldwide, humans are facing high risks from natural hazards, especially in coastal regions with high population densities. Rising sea levels due to global warming are making coastal communities' infrastructure vulnerable to natural disasters. The present study aims to provide a coupling approach of vulnerability and resilience through restoration and conservation of lost or degraded coastal natural habitats to reclamation under different climate change scenarios. The integrated valuation of ecosystems and tradeoffs model is used to assess the current and future vulnerability of coastal communities. The model employed is based on seven different biogeophysical variables to calculate a natural hazard index and to highlight the criticality of the restoration of natural habitats. The results show that roughly 25% of the coastline and more than 5 million residents are in highly vulnerable coastal areas of mainland China, and these numbers are expected to double by 2100. Our study suggests that restoration and conservation in recently reclaimed areas have the potential to reduce this vulnerability by 45%. Hence, natural habitats have proved to be a great defense against coastal hazards and should be prioritized in coastal planning and development. The findings confirm that natural habitats are critical for coastal resilience and can act as a recovery force of coastal functionality loss. Therefore, we recommend that the Chinese government prioritizes restoration (where possible) and conservation of the remaining habitats for the sake of coastal resilience to prevent natural hazards from escalating into disasters.

Climate Risk Assessment (CRA) consists of four components based on the IPCC framework: (a) hazard, (b) exposure, (c) vulnerability, and (d) response/adaptation. Such assessment is essential not only to understand how each hydroclimatic hazard can have an impact on urban areas, but also to develop climate adaptation strategies. Although a wide range of tools for CRA have been developed, several challenges limit their consistent application in the urban environment. First, a typical urban area can be exposed to multiple natural hazards, which requires a framework to assess multi-hazard multi-risk impacts. Furthermore, characteristics of hydroclimatic hazards (e.g., magnitude and spatio-temporal variations) can alter due to climate changes. Finally, future projections are scenario-based, which inevitably introduces uncertainty in CRA. In this context, CLIMAAX presents a comprehensive CRA toolbox including a series of practical workflows in terms of Python scripts, each focusing on a specific climate hazard. Together, the workflows enable consistent multi-hazard assessments. The hazards considered in the CLIMAAX toolbox include river and coastal flooding, heavy rainfall, urban heatwaves, relative and agriculture droughts, wildfire, heavy snowfall and blizzards, and windstorm. The toolbox is available for implementation to any European region, but it can be extended to other regions with minor modifications to input data. To select climate projections, the CLIMAAX toolbox provides a workflow assessing bias and uncertainty of climate models/scenarios for any region in Europe. Using the CRA outputs, the toolbox supports key risk assessments that account for severity, urgency and capacity, enabling the integration of risk responses as the final step of CRA.This study has a twofold aim. First, it attempts to showcase applications of three CLIMAAX workflows, including river flooding, heavy rainfall, and coastal flooding, to the city of Genoa, Italy. Genoa’s river networks have experienced multiple flood events, like the ones in November 2011 and October 2014. Furthermore, the city is also affected by intense rainfall, as shown by the heavy precipitation event in November 2025, which caused flash flooding and street inundation. Moreover, coastal flooding represents an additional hazard, with the October 2018 event impacting beaches and coastal infrastructure. Based on the CRA results, river flooding was identified with the highest risk priority in Genova. Second, flooding hazard-specific risk outputs were translated into a spatially-explicit data-driven assessment of public-private adaptation infrastructure options at the city scale. Building on the CLIMAAX workflows, neighborhood-scale risk layers were mapped for pluvial flooding from heavy rainfall, fluvial flooding along Genoa’s river network, and coastal flooding to study adaptation options targeting different risk components. For a set of these options, alternative deployment strategies were explored, and avoided impacts alongside capital expenditures and operation and maintenance costs were quantified. This enables sub-city cost-benefit comparison of individual and combined infrastructures that best align with severity, urgency and capacity constraints, producing a basis for prioritizing adaptation pathways across Genoa’s neighborhoods. Acknowledgement: This research work was carried out as part of the CLIMAAX project with funding received from the European Union’s Horizon Europe – the Framework Programme for Research and Innovation (2021-2027) under grant agreement No. 101093864.

ObjectiveThis study tests the impacts of Digital Elevation Model (DEM) data on an exposure assessment methodology developed to quantify flooding of coastal infrastructure from storms and sea level rise on a regional scale. The approach is piloted on the United States Virgin Islands (USVI) for a one-hundred-year storm event in 2050 under the IPCC's 8.5 emission scenario (RCP 8,5). MethodFlooding of individual infrastructure was tested against three different digital elevation models using a GIS-based coastal infrastructure database created specifically for the project using aerial images. Inundation for extreme sea levels is based on dynamic simulations using Lisflood-ACC (LFP). ResultsThe model indicates transport and utility infrastructure in the USVI are considerably exposed to sea level rise and modeled storm impacts from climate change. Prediction of flood extent was improved with a neural network processed SRTM, versus publicly available SRTM (~30 m) seamless C-band DEM but both SRTM based models underestimate flooding compared to LIDAR DEM. The modeled scenario, although conservative, showed significant flood exposure to a large number of access roads to facilities, 113/176 transportation related buildings, and 29/66 electric utility and water treatment buildings including six electric power transformers and six waste water treatment clarifiers. ConclusionThe method bridges a gap between large-scale non-specific flood assessments and single-facility detailed assessments and can be used to efficiently quantify and prioritize parcels and large structures in need of further assessment for regions that lack detailed data to assess climate exposure to sea level rise and flooding caused by waves. The method should prove particularly useful for assessment of Small Island Developing State regions that lack LIDAR data, such as the Caribbean.

Salt marsh peat deposits at many locations around the world, including the U. S. Atlantic and Gulf coasts, provide proxy data for reconstructing the history of changes in relative sea level (RSL). A geological database of index points has been established through sampling and analysis of salt marsh peat collected at many of those locations. However, spatial gaps in this database still exist in the available data for southern New England. A notable gap is the southern coast of Rhode Island, primarily due to the lack of precalculated tidal datums and the complexity of producing records in an active back barrier salt marsh setting. The primary goal of this research was to provide additional data to fill those gaps by establishing rates of sea-level rise in the salt marshes of the coastal ponds behind the barrier beach of southern Rhode Island. This project used basal-peat deposits, radiocarbon dating, and foraminifera that are indicators of local tide level. Exploratory/reconnaissance coring of the salt marshes of three ponds: Ninigret Pond, Quonochontaug Pond and Winnapaug Pond generally revealed very shallow peat deposits compared to those found around Narragansett Bay. Three locations were found that provided data sufficient to calculate usable rates of sea-level rise. The deepest peat deposit and oldest date was recovered at a salt marsh adjacent to Wildflower Road (WFN), Charlestown, RI. At 121 cm below the surface and a date of 1230 yrs. BP, the corresponding sedimentation rate and estimated rate of sea-level rise from the age/depth relationship was ~ 1 mm/yr. using the surface. This depth/age relationship and estimated rate of sea-level rise provides a frame of reference for sea level dynamics consistent with data of the same age and older in Narragansett Bay. Climate change, rising sea-level and storm waves have had an impact on the coastal salt marshes of Rhode Island and coastal communities of all the states along the U. S. Atlantic coast. The potential impacts from sea-level rise to salt marsh ecosystem services, coastal infrastructure, and coastal cultural resources, especially older indigenous cultural sites are likely to increase for decades if not centuries to come.

Partial replacement of cement for waste aggregates in concrete coastal and marine infrastructure: A foundation for ecological enhancement?

This is a compilation of policies and practices that contribute to bridging a knowledge gap with regards to climate change impacts and adaptation for coastal transport infrastructure. It presents examples of legal and policy approaches, as well as of reports, studies and guidance to support climate risk, vulnerability and impact assessment, and the development of effective adaptation response measures for coastal transport infrastructure, with a view to informing and inspiring policy makers, national authorities, transport managers, infrastructure owners, and other stakeholders in their efforts.

Sea-level rise impacts on transport infrastructure: The notorious case of the coastal railway line at Dawlish, England

A framework for promoting natural climate solutions in the agriculture sector