Coastal Erosion Risk Research Articles

Impact of risk experience and personal exposure on coastal flooding and coastal erosion risk perception and coping strategies

The increasing vulnerability of coastal areas to climate change and coastal Risks, is now clearly established due to sea level rise. These events, which have become commonplace, constitute a danger for residents and for public facilities, roads, homes, etc. and make these areas more and more vulnerable. Although measures to reduce this vulnerability of coastal cities have been identified by experts and authorities, a resistance exists to their implementation by the inhabitants of these areas exposed to coastal risks. The aim of our study is to investigate risk perception and coping strategies used by inhabitants of areas at risk of coastal flooding and coastal erosion, and to identify potential differences between these two types of coastal risks. More precisely, this study seeks to identify the major predictors of the willingness to cope using Bayesian regression. 208 inhabitants of coastal areas exposed at risk of coastal flooding and erosion in Pays de la Loire, region of western France, participated to our study. Results reveal that coastal erosion is perceived as a greater threat, essentially because it is perceived as more frightening than coastal flooding. Moreover, our results showed that past experiences of coastal risks had an impact on the willingness to use active coping strategies and that there were major differences in the choice of strategy depending on the risks. These results are discussed in terms of risk management.

Morphodynamic adaptation of a tidal basin to centennial sea-level rise: The importance of lateral expansion

Global climate changes have accelerated sea-level rise (SLR), which exacerbates the risks of coastal flooding and erosion. It is of practical interest to understand the long-term hydro-morphodynamic adaptation of coastal systems to SLR at a century time scale. In this work we use a numerical model to explore morphodynamic evolution of a schematized tidal basin in response to SLR of 0.25–2.0 m over 100 years with special emphasis on the impact of lateral basin expansion. Starting from a sloped initial bed, morphodynamic development of the system leads to the formation of alternating bars and meandering channels inside the tidal basin and an ebb-tidal delta extending seaward from the basin. Imposing rising sea level causes progressive inundation of the low-lying floodplains, found along the basin margins, inducing an increase in basin plain area and tidal prism, as well as intertidal area and storage volume. Although the overall channel-shoal structure persists under SLR, lateral shoreline expansion alters the basin hypsometry, leading to enhanced sediment export. The newly-submerged floodplains partly erode, supplying sediment to the system for spatial redistribution, hence buffering the impact of SLR. The vertical accretion rate of the tidal flats inside the tidal basin lags behind the rate of SLR. However, lateral shoreline migration under SLR creates new intertidal flats, compensating intertidal flat loss in the original basin. In contrast, a constrained tidal basin without low-lying floodplains is subject to profound drowning and tidal flat losses under SLR. Overall, the model results suggest that an unconstrained tidal system allowing lateral shoreline migration has buffering capacity for alleviating the drowning impact of SLR by evolving new intertidal areas, sediment redistribution and morphodynamic adjustment. These findings suggest that preserving tidal flats located along the margins of tidal basins (instead of reclaiming them) sustains the system's resilience to SLR.

Coastal erosion risk assessment in the dynamic estuary: The Meghna estuary case of Bangladesh coast

Erosion is one of the predominant hazards in coastal Bangladesh. For implementing effective adaptation and mitigation strategies, assessment of risk to coastal erosion is crucial. This study aimed to assess the levels of risk to coastal erosion in the Meghna estuary, a major erosion-prone area in the coastal region of the country impacted by abrupt changes in hydrological and geomorphological conditions. Using physical, environmental, and socio-economic geospatial data, this is the first attempt in assessing erosion risk and characterizing three main risk components: hazard, vulnerability, and exposure at a regional extent in the estuary. A total of 19 indicators were considered, and statistical methods assisted with the Analytic Hierarchy Process (AHP) were used for the construction of hazard, vulnerability, and exposure indices, which were then integrated to calculate erosion risk comprehensively at the lowermost administrative unit (union) level throughout the study area. The results of hazard and vulnerability analyses depicted 35.72% and 46.69% areas as highly hazard-prone and highly vulnerable to erosion, respectively. Assessment of the exposure index exhibited 42.25% area as highly exposed to coastal erosion in the estuary. Finally, the results quantified different levels of risk as very high (14.91%), high (19.36%), moderate (23.40%), low (23.91%), and very low (18.41%). Among 161 coastal unions, 45 unions were identified as high to very high erosion risk-prone areas, located in the coasts of Bhola, Noakhali, and Barishal districts including their major islands. The validation result confirmed a reasonable level of acceptance of the calculated risk map, despite several data limitations. The geospatial distribution of different risk categories presented in this paper can assist relevant authorities with reliable spatial information in formulating improved erosion risk mitigation policies in the most dynamic estuary of the country.

The utilisation of satellite imagery and community perceptions to assess the impacts of sea encroachment in the West Coast of Cameroon at Limbe

Coastal erosion associated to sea encroachment is a major problem at the West Coast of Limbe, specifically in the Debundscha Fishing Port (DFP). This study sought to assess the physical vulnerability of the West Coast of Limbe to coastal erosion associated to sea encroachment. This was achieved by assessing: i) the physical vulnerability of the West Coast to coastal erosion; ii) land cover changes and iii) community perception at DFP to sea encroachment and coastal erosion in the past 30 years. Three variables: rock type, adjacent land use and coastal protection were used to assess the vulnerability of the West Coast to coastal erosion. Landcover / coastal changes were assessed from satellite images from 1986 to 2018. Semi-structural interviews were used to acquire knowledge on the population’s perception and impact of the studied hazards. A cost benefit approach was used to weigh the potentials of these localities to adapt to coastal erosion. The DFP and Idenau Beach were identified as major hotspots of coastal erosion with an annual rate of >100 m². Landcover changes showed a net increase in water levels inland and into settlements. The population is knowledgeable and is aware of the risk of sea encroachment and coastal erosion. The physical, socio-economic and health effects were: destruction of mangroves;relocation; malaria, typhoid and abdominal illnesses respectively. Coping strategies included the use of sandbags, building on higher grounds and on embankments. Cost benefit analysis ranked vegetative cover as the best option environmentally and financially viable to reduce coastal erosion from sea encroachment at the West Coast.
 Key words: Sea encroachment, coastal erosion, physical vulnerability, perception, Debundscha Fishing Port

The Price of Coastal Erosion and Flood Risk: A Hedonic Pricing Approach

Accelerated coastal erosion and elevated risks of flooding due to global warming put enormous burden on the ecosystems and economic health of coastal communities. Optimal policies to lessen these negative impacts require an estimation of their costs and benefits. The aim of this paper is to calculate the costs of beach erosion and flood risk through the valuation of property prices in Hilton Head Island, a barrier island located in South Carolina, USA. Spatial lag hedonic pricing was introduced in order to account for spatial autocorrelation in the dataset. The results show that properties that are located within the zone of high, or very high, flood risk experience a 15.6% reduction in value. The implicit price of being located close to an eroded beach is approximately 26% of the price of an oceanfront property. However, this negative impact on property value diminishes with distance from the shoreline.

Shoreline Dynamics in East Java Province, Indonesia, from 2000 to 2019 Using Multi-Sensor Remote Sensing Data

Coastal regions are one of the most vulnerable areas to the effects of global warming, which is accompanied by an increase in mean sea level and changing shoreline configurations. In Indonesia, the socioeconomic importance of coastal regions where the most populated cities are located is high. However, shoreline changes in Indonesia are relatively understudied. In particular, detailed monitoring with remote sensing data is lacking despite the abundance of datasets and the availability of easily accessible cloud computing platforms such as the Google Earth Engine that are able to perform multi-temporal and multi-sensor mapping. Our study aimed to assess shoreline changes in East Java Province Indonesia from 2000 to 2019 using variables derived from a multi-sensor combination of optical remote sensing data (Landsat-7 ETM and Landsat-8 OLI) and radar data (ALOS Palsar and Sentinel-1 data). Random forest and GMO maximum entropy (GMO-Maxent) accuracy was assessed for the classification of land and water, and the land polygons from the best algorithm were used for deriving shorelines. In addition, shoreline changes were quantified using Digital Shoreline Analysis System (DSAS). Our results showed that coastal accretion is more profound than coastal erosion in East Java Province with average rates of change of +4.12 (end point rate, EPR) and +4.26 m/year (weighted linear rate, WLR) from 2000 to 2019. In addition, some parts of the shorelines in the study area experienced massive changes, especially in the deltas of the Bengawan Solo and Brantas/Porong river with rates of change (EPR) between −87.44 to +89.65 and −18.98 to +111.75 m/year, respectively. In the study areas, coastal erosion happened mostly in the mangrove and aquaculture areas, while the accreted areas were used mostly as aquaculture and mangrove areas. The massive shoreline changes in this area require better monitoring to mitigate the potential risks of coastal erosion and to better manage coastal sedimentation.

Coastal erosion risk assessment in the coastal area of Muara Asam Asam, Tanah Laut Regency

Coastal erosion is the process of land erosion in coastal areas due to waves and ocean currents which reduce land and can adversely affect socio-economic activities in coastal areas. Coastal erosion risk assessment in the estuary is a development of previous research, because the erosion and accretion processes do not only occur along the shoreline, but also on the side facing river water bodies, due to the confluence of fluvial and marine processes. The landward shift of the shoreline in the Muara Asam Asam coastal area has reached 90 meters in the last 28 years, and has been detrimental because the area is a densely populated area with major economic activities in the fisheries and agriculture sectors. This study aims to determine the coastal erosion risk level zones based on the relationship among vulnerability and consequence parameters, through distance decay weighted based method. The results indicate that Muara Asam Asam has high risk zones of coastal erosion, especially in densely populated residential areas and dry land agriculture on the west side of the estuary, due to the lack of implementation of preventive measures through hard coastal structure and coastal zoning policy to protect socio-economic activities and coastal ecological environments.

Aging in High-Risk Coastal Regions: Examining Social Infrastructure Needs of Older Adults Living in the Gulf Coast

This study examines how coastal erosion, flooding susceptibility, and extreme hazard risk in Louisiana communities shape decisions to age in place. The decision to age in place is not only related to one’s physical health and cognitive capabilities but strongly connected to neighborhood cohesion, sociocultural contexts, economic resources, familiarity with surroundings, and a sense of security. However, research on the types of individual and community resources that older adults need in order to successfully age in environmentally vulnerable communities is exceptionally sparse. Using in-depth interview data collected from older adults (n=20) living in coastal Louisiana parishes, this research aims: 1) to gain a deeper understanding of how coastal erosion and frequent flooding influence the decision to age in place; 2) to compile evidence as to how coastal communities can create resources that promote resilience, despite environmental risk; and 3) to use this evidence to increase awareness and enhance policy discussions on coastal adaptation.

Coastal erosion risk assessment to discuss mitigation strategies: Barra-Vagueira, Portugal

Worldwide coastal zones present serious erosion problems that cause loss of territory. This phenomenon exposes people and goods to the threat, being necessary to carry out a well-founded management of these areas. Coastal erosion risk assessment methodologies are an important tool for coastal management. The main goal of the present study was to evaluate and discuss coastal management strategies based on the application of a methodology of coastal erosion risk classification, allowing easy comparison of scenarios. The study was developed for the Portuguese coastal stretch Barra-Vagueira. CERA methodology and its plugin for QGIS software were applied in order to assess the erosion risk of Barra-Vagueira stretch for different coastal erosion mitigation scenarios. First, an analysis of the coastal erosion risk was carried out based on bibliographic elements and present situation characterization. Subsequently, the erosion risk was assessed considering defence, relocation and nourishment strategies scenarios and climate change scenarios. The study based on bibliographic elements shows that the coastal region between Barra and Vagueira has a high risk of coastal erosion. Generally, the different scenarios tested represent variations on coastal erosion risk classification, allowing a simple first approach to evaluate coastal erosion mitigation scenarios, helping planning and decision-makers. Performing measures that allow to constrain the shoreline retreat, as artificial nourishments, leads to greater benefits in reducing the area of the territory classified with higher risk. New coastal defence structures allow to mainly decrease the stretch's susceptibility to coastal erosion. The relocation of population leads to a decrease in the area of the territory classified as very high-risk. Climate change increases the erosion risk.

Perceptions of and responses to coastal erosion risks: The case of Cotonou in Benin

Intensive erosion has affected the coastal zone of Cotonou for several decades. An analysis of satellite images showed an average coastline retreat of 115 m in the study area over the period 2002–2013 with several hundred houses destroyed. Since 2014, a stabilisation of the coastline is observed. This study aimed at identifying the at-risk population and at analysing the perceptions of people who experience and those who manage coastal erosion risk, as well as the responses adopted. Based on four criteria and their hierarchy, we identified five profiles of inhabitants in this risk zone. (1) Wealthy people who leave the zone when they are affected or (2) fall into the category of people in danger in case they cannot migrate. (3) Fishermen who deliberately stay near the sea. (4) The most precarious people, trapped in the risk zone. Finally, (5) poor newcomers who continually increase the at-risk population. With the recent stabilisation of the coastline, the national authorities manage the “hazard” component of the risk. However, the majority of the population is not serene. The anthropogenic stress linked to evictions gradually replaced the stress to be engulfed by the sea. We conclude that the “vulnerability” component of the risk is not yet resolved. All categories of the population in this sensitive area need to be secured. Cooperation among multiple levels of governance, the application of land use planning regulations and of the Kampala Convention and the involvement of local communities are all measures which will enable to meet this objective.

Flow field impact assessment of a tidal farm in the Putuo-Hulu Channel

Waters surrounding Zhoushan Archipelago have the most abundant tidal current energy in China, which makes it a promising site for tidal farm construction in the future. Before deploying tidal current turbines, the potential environmental impacts on surrounding waters must be evaluated. In this work, we focus on the flow field impact assessment of an assumed tidal farm installed in Zhoushan Putuo-Hulu Channel. First, in order to evaluate the tidal characteristics there, a 2-month ADCP campaign is carried out, and a 3-D hydrodynamic model is established and validated with the in-situ measurements. Additionally, tidal current velocity and water depth as well as flow heading asymmetry information are used to evaluate the tidal stream exploitability within this channel. Second, a tidal farm consisting of 115 turbines is planned and assumed to be deployed throughout this channel. Blade element momentum method is used to numerically characterize the flow-turbine interactions, and then the spatial-temporal flow field variations caused by the assumed tidal farm are evaluated. It can be seen from the results that the peak flow speed reduction produced by the tidal farm could be over 0.5 m/s within the wake zones, while the flow velocity increment along two islands could reach 0.6 m/s. In particular, a flow speed phase shift phenomenon can be observed. Besides, the water level experiences a small overall rise, and the difference compared with the reference is within ±3.0 cm. Moreover, the seabed shear stress within the wake zones could drop by 65%, while the areas along the two islands might see over 100% increase, indicating the risk of sediment deposition and coastal erosion.

Learning from risk reduction pilot projects for enhancing long-term adaptation governance: The case of Mauritius Island (Indian Ocean)

In Mauritius island in the Indian Ocean, as in most low-lying coastal areas and Small Island Developing States in particular, coastal risks affect community livelihood, economic prosperity and the degradation of natural ecosystems. Risks of coastal erosion and marine flooding result both from climate-related ocean changes and anthropogenic drivers such as inappropriate coastal development and structural protection measures. Poor development planning and lack of coordination between public and private actors have increased the exposure of human assets along the Mauritius coastline. To reduce these risks, the government leads risk reduction activities in coastal zones, functioning on a centralized top-down governance approach. In recent years, this governance framework has been evolving by opening up participatory channels and exploring a long-term adaptation perspective. Progress is driven by international engagements and demonstration projects to embrace soft measures, nature-based options and integrated solutions. We review a selection of pilot projects undertaken by the government that illustrate flexibility in a ‘learning by doing’ model. However, we find that certain governance arrangements do not allow to draw the most from ad hoc projects because they do not feed into a long-term comprehensive plan. We consider the role of evidence and risk assessments, learning processes and coordination mechanisms as key governance mechanisms required for a robust and evolving national coastal risk reduction and adaptation policy framework.

Nurturing Community Engagement in Coastal Erosion Risk Management in Kuala Selangor, Malaysia

The coastal areas in Peninsular Malaysia have been experiencing immense coastal erosion issues. The government executed many initiatives to reduce coastal erosion and damages. This study aims at examining the local community's beliefs and role in protecting their coastal areas. Pantai Jeram and Pantai Remis became the case study, and a questionnaire survey using purposive sampling was conducted involving 212 respondents. A focus group discussion was also operated. Results demonstrated severe damage to the coastal area and revealed the awareness of the residents and their willingness to participate in community engagement programs.Keywords: Coastal Zone; Coastal Erosion; Coastal Risk Management; Community EngagementeISSN: 2398-4287 © 2020. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v5i13.2053

An Integrated Approach to Analyze Sedimentary Stock and Coastal Erosion in Vulnerable Areas: Resilience Assessment of San Vicenzo’s Coast (Italy)

The assessment of coastal erosion risk is a major challenge, since environmental and geomorphic features, together with sea state parameters, can seriously change the configuration of coastal areas. In addition, the anthropic actions of the coastal communities may also drastically modify the configuration of the coast in vulnerable areas. In this study, a linkage between regional mapping guidelines and national geological cartography procedures is presented as a meaningful tool in the geomorphic trends analysis for the integrated mapping of the main morphological patterns of San Vincenzo’s coastal area, in the region of Tuscany (Italy). Comparing and joining different procedures—which have different scales and topics—requires adapting the fields and the information provided in maps and databases. In this case study, a GIS morpho-sedimentological approach is developed. This GIS approach enables us to cover several issues simultaneously, such as the representation of coastal active processes, the adaptation of regional and national cartography to coastal erosion assessment, and lastly the calculation of the sedimentary stock analysis, since it represents the first attribute of coasts to be preserved in a resilience-oriented integrated assessment.

Coastline changes and their effects on land use and cover in Subang, Indonesia

Indonesia is at high risk of coastal erosion. Therefore, is important to understand the current status over a large area in order to devise protection strategies. This study measured the coastline changes and examined the land use and cover affected by coastal changes in Subang, Indonesia, using Landsat images from 1990 and 2018. The modified normalized difference water index (MNDWI) was used to separate the water and non-water features of the images, and land use and cover were classified using object-based image analysis based on the red, green, and blue bands and normalized difference vegetation index (NDVI). The results revealed considerable coastal erosion in Legonkulon. In the most extreme case, the coastline had moved 2361.46 m inland, and the total area lost to erosion was 1012.25 ha. This area was mostly covered by fishponds (983.34 ha) in 1990. Given that the fishery sector is the main livelihood of communities in the study area, the disappearance of fishponds might have affected their income and worsened their poverty. We found marked coastal accretion in Blanakan. In the most extreme case, the coastline had moved 1695.61 m seaward from 1990 to 2018, adding a total area of 1856.62 ha. The new areas were used as fishponds (1738.95 ha) in 2018. Although the accretion exceeded the erosion, the distributions differed regionally. Therefore, a regional protection strategy is necessary.

Risk assessment as tool for coastal erosion management

The coastal zone of Cartagena city, Colombia provides illustration for applying risk assessments as a basis for guiding coastal management. Much of this coastal reach is heavily urbanized with a few areas of suburban to rural zones. In this study 32.6 km of shoreline under the city's jurisdiction were evaluated for coastal erosion management, calculating the Hazard and Vulnerability Indexes, which together constitute the Coastal Erosion Risk Index which provides a single numerical evaluation of risk. A range of variables were utilized in the calculations including forcing processes (wave height, storm surge, littoral exposure), coastal susceptibility (sandy and rocky shores: dune height, percent washovers, beach width, beach slope, cliff/platform, rock types, structure, weathering), as well as socio-economic, ecological and cultural factors (e.g., land use, percent urbanized, population density, infrastructure, cultural heritage, agency conservation/protection, ethnic communities, etc.). Coastal forcing and susceptibility are the basis for determining the Hazard, resulting mostly from induced susceptibility as a result of 60 years of over-reliance on shore-hardening structures, interrupting/reducing sediment supply, and over-development in terms of urbanization (loss of protective landforms, irreversible coastline modification, beach narrowing, and the growing coastal squeeze). From a management viewpoint, much of the Cartagena urban area has limited options, but the buffer zone between the shoreline and development must be increased (e.g., no new development; planned retreat), building codes updated (e.g., building floors at/below ground level should be flood-proofed, and have uses compatible with/recoverable from flooding/wave impact), and minimize additional shore-hardening (e.g., utilize beach nourishment). Rural and suburban areas in the region still have time to adopt more stringent management including development bans, disallowing replacement of buildings lost to erosion/flooding, large set-back requirements for new development, utilizing ecosystem management for natural protection, and removal of some groin systems. Virtually all management solutions will be costly, so plans are needed at the government level to develop financing systems.

Coastal Management Software to Support the Decision-Makers to Mitigate Coastal Erosion

There are no sequential and integrated approaches that include the steps needed to perform an adequate management and planning of the coastal zones to mitigate coastal erosion problems and climate change effects. Important numerical model packs are available for users, but often looking deeply to the physical processes, demanding big computational efforts and focusing on specific problems. Thus, it is important to provide adequate tools to the decision-makers, which can be easily interpreted by populations, promoting discussions of optimal intervention scenarios in medium to long-term horizons. COMASO (coastal management software) intends to fill this gap, presenting a group of tools that can be applied in standalone mode, or in a sequential order. The first tool should map the coastal erosion vulnerability and risk, also including the climate change effects, defining a hierarchy of priorities where coastal defense interventions should be performed, or limiting/constraining some land uses or activities. In the locations identified as priorities, a more detailed analysis should consider the application of shoreline and cross-shore evolution models (second tool), allowing discussing intervention scenarios, in medium to long-term horizons. After the defined scenarios, the design of the intervention should be discussed, both in case of being a hard coastal structure or an artificial nourishment (third type of tools). Finally, a cost-benefit assessment tool should optimize the decisions, forecasting costs and benefits for each different scenario, through definition of economic values to the interventions and to the land/services/ecosystems, weighting all the environmental, cultural, social and historical aspects. It is considered that COMASO tools can help giving answers to the major problems of the coastal planning and management entities, integrating transversal knowledge in risk assessment, physical processes, engineering and economic evaluations. The integrated coastal zone management needs these tools to ensure sustainable coastal zones, mitigating erosion and climate change effects.

Watching the Beach Steadily Disappearing: The Evolution of Understanding of Retrogressive Breach Failures

Retrogressive breach failures or coastal flow slides occur naturally in the shoreface in fine sands near dynamic tidal channels or rivers. They sometimes retrogress into beaches, shoal margins and riverbanks where they can threaten infrastructure and cause severe coastal erosion and flood risk. Ever since the first reports were published in the Netherlands over a century ago, attempts have been made to understand the geo-mechanical mechanism of flow slides. In this paper we have established that events, observed during the active phase, are characterized by a slow but steady retrogression into the shoreline, often continuing for many hours. This can be explained by the breaching mechanism, as will be clarified in this paper. Recently, further evidence has become available in the form of video footage of active events in Australia and elsewhere, often publicly posted on the internet. All these observations justify the new term ‘retrogressive breach failure’ (RBF event). The mechanism has been confirmed in flume tests and in a field experiment. With a better understanding of the geo-mechanical mechanism, current protection methods can be better understood, and new defense strategies can be envisaged. In writing this paper, we hope that the coastal science and engineering communities will better recognize and understand these intriguing natural events.

Multicriteria GIS-based estimation of coastal erosion risk: Implementation to Aveiro sandy coast, Portugal

Coastal risk assessments have an essential role in decision making and coastal management. In this context, this work presents a new assessment process for the Coastal Erosion Risk Assessment (CERA2.0). This methodology aims to perform coastal erosion risk assessments for a medium-term horizon, over a wide range of coastal environments and scales, with considerable accuracy and efficiency. It follows closely the SPRC (Source – Pathway – Receptor – Consequence) conceptual model by evaluating risk propagation in four modules: susceptibility, value, exposure and hazard (coastal erosion). Subsequently, these are combined to generate vulnerability, consequence and risk maps. A total of twelve indicators are considered. For easier application of the methodology, a QGIS plugin was developed. Given the required inputs, the plugin computes all procedures and provides the results in a georeferenced format. The new procedure is demonstrated for the Aveiro district coastal region, a sandy coast in Portugal. The results indicate that Aveiro has a coastline with predominantly high to very high risk to coastal erosion. The most threatened areas are the coastlines near Furadouro and Vagueira. The method showed to be easily applicable without the necessity of highly detailed data, albeit is still requires a fair amount of it, representing an advantage not common in these types of methodologies. Hence, CERA2.0 is intended to be applied by entities that do not have access to large amounts of data in their study areas or that require coastal erosion risk assessments in limited time windows.

Applying Uncertain Science to Nature-Based Coastal Protection: Lessons From Shallow Wetland-Dominated Shores

Climate change and associated sea-level rise alongside the potential for alterations in the magnitude and frequency of extreme storm events, rapidly rising coastal populations, and a legacy of coastal land reclamation have led to the consideration of nature-based approaches towards coastal flood and erosion protection over recent years. The descriptions of such approaches highlight the flood protection value of natural coastal features but examples of their implementation remain few and far between and nature-based solutions to the rising coastal flood and erosion risk can certainly not (yet) be considered mainstream. One key problem around the implementation of these types of approaches has, arguably, been the relative lack of perceived scientific certainty, amongst stakeholders, surrounding the efficiency with which natural landforms reduce wave action on landward lying structures and the persistence of such landforms in an uncertain future. This makes nature-inclusive approaches less attractive to more traditional engineering-only approaches that rely solely on one ‘hard’ structure with a well-defined impact on waves and a specified design life. Using existing evidence for the coastal protection function of salt marshes, this paper offers a new perspective on this apparent lack of scientific certainty by offering a ‘no-regret’ application of existing science that allows decision makers and coastal planners to implement nature-inclusive approaches to coastal flood and erosion risk reduction measures with greater confidence.