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The Mediterranean basin is one of the most vulnerable regions worldwide due to its population density, the concentration of economic activities along the coasts and borderline climatic balance. It is identified as one of the most critical erosion hotspots in Europe, mainly due to the degradation of coastal areas, overexploitation and unsustainable practices affecting beach tourism, agriculture and fishing. The region is also affected by other phenomena such as storms and floods, which are exacerbated by climate change. To mitigate and adapt to these environmental and climatic changes, Nature based Solutions (NbSs) are considered a promising step-forward. However, despite their global recognition in both research and policy, few scientific papers and documents on the state of NbSs implementation for coastal risk management in the Mediterranean exist. This paper aims to provide an understanding of the status of NbS adoption for coastal risk management in the Mediterranean through a literature review. Out of 162 scientific papers and documents, only 23 were found to be relevant to the study. Through the definition and support of an innovative matrix-based approach, the analysis of the state of adoption of NbSs have been performed. Despite the limited information on the state of the adoption of NbSs for coastal risk management in the Mediterranean due to the low numbers of scientific research and documents available, some key considerations have been revealed. • The Mediterranean basin is the most critical erosion hotspots in Europe. • NbSs are recognized a promising step-forward in coastal risk management. • Novel framework for the analysis of past and present NbS implementation. • Few studies report the adoption of NbSs for Mediterranean coastal risk management. • NbS for coastal risk management in the Mediterranean is still in an experimental phase. [ABSTRACT FROM AUTHOR]

Coastal sites have been recognized to be among the most productive and dynamic regions. Nevertheless, these areas have been disrupted due to the rapid expansion of human interventions and climate change. Coastal ecosystems are becoming more endangered by the probable adverse effects of climate change as revealed by IPCC panel. The main objective of this paper is to integrate Machine Learning (ML) models to spatially predict coastal vulnerability along the Mediterranean coast of (Tangier-Tetouan), Morocco. Different models including Artificial neural network (ANN), Decision Tree (DT), logistic regression (LR), random forest (RF), and Support vector machine (SVM) are used on 10033 points to represent the vulnerability in terms of (high, moderate, and low), determined by the coastal vulnerability index (CVI). Eight coastal vulnerability predictors (Slope, Elevation, Tidal range, Sea level rise, maximum wave height, Natural habitat, Geomorphology, and Shoreline change rate) were considered as input for each model. The obtained dataset was split into two parts: 30% for testing and 70% for training. The presented models were examined on various parameters, such as accuracy, recall, F1 score, root mean square error (RMSE), and kappa index. The findings show that accuracy and Kappa statistics for RF and DT and SVM ranged from (92–99%) which indicates a better performance than other proposed models. The approach is considered an appropriate tool for predicting and mapping coastal vulnerability and can make significant contributions to the successful management of coastal zones. Additionally, it can aid in the development of public interest and promote the planning, creation, and execution of adaption measures. The prediction was applied over (∼124 km) of the shoreline. Results showed that about 19.95% (∼27.73 km) of the shoreline is highly vulnerable, while 20.92% (∼25.95 km) is moderately vulnerable and 59.1% (∼73.32 km) presents a low vulnerability. • This paper aims to integrate Machine Learning (ML) models. • We spatially predict coastal vulnerability along Mediterranean coast of Morocco. • Different models including Artificial neural network (ANN) are used. • The models are used on 10033 points to represent the vulnerability coastal vulnerability index (CVI). • Different predictors were considered for each model. [ABSTRACT FROM AUTHOR]

Beaches can serve as a valuable asset to any community, which can gain a massive source of income from them; in fact, beach tourism is ever more frequently the essential target of countries, aimed at attracting foreign investment or exchange. In this frame, prediction of coastal evolution at large scales is very important for coastal management and first conceptual design. Management strategies, almost at the early stages of the projects, may likely involve numerical simulations, but they can be extremely laborious, computing demanding and intensely time-consuming especially when involving either wider coastal domain or longer time scales that basically encompasses the majority of coastal projects by now. Analytical solutions of the Diffusion Shoreline Equation (DSE) can be a valid alternative. I n these frames, given the surprisingly good predictive capabilities, they can isolate essential features of the processes, making them more readily comprehended, and can avoid cumulative errors associated with the accuracy of computational time-stepping models. Nevertheless, the rather complex mathematical form makes their use extremely challenging and confines them in the realm of high mathematic s. Ciccaglione et al. (2023) provided analytical solutions of the DSE for finite beaches bounded by outcrops of whatever length (bypassing or non-bypassing groin compartments). Differently from the other studies, the authors checked the applicability range of the solutions through the comparison with reliable numerical models; furthermore, using curve fitting analysis simple design tools were suggested to aid engineers in the practical applications. In this paper, a deep focus is given on the case of a bypassing groin compartment, and easy-to-use formulae are given to assess the lifetime of beach fill projects. A simple semi-theoretical solution is also given for the case of a compartment bounded by a very short groin, by introducing a "convective term" modelled via a Heavy-side function, H (x). The practical usefulness of this solution is proved through an application to the evolution of a real beach along Italy's Adriatic coast. • Long-term shoreline evolution is important for coastal management and planning. • Analytical solutions are valid tools for estimating shoreline change in a bypassed cell. • Simple formulae are derived for the response of a beach fill into bypassing cells. • The applicability range is limited by the shortness of the bypass groin. • "convective" correction is checked against a coastal segment of the Adriatic coast. [ABSTRACT FROM AUTHOR]

Coastal areas stand out because of their rich biodiversity and high tourist potential due to their privileged geographical position. However, one of the main problems in these areas is the generation of waste and its management, which must consider technical and sustainable criteria. This work aims to conduct a systematic review of the scientific literature on integrated solid waste management (ISWM) by considering scientific publications on the scientific basis for the proposal of sustainability strategies in the context of use and efficiency. The overall method comprises i) Search strategy, merging and processing of the databases (Scopus and Web of Science); ii) Evolution of coastal zone waste management; iii) Systematic reviews on coastal landfills and ISWM in the context of the circular economy; and iv) Quantitative synthesis in integrated waste management. The results show 282 studies focused on coastal landfills and 59 papers on ISWM with the application of circular economy criteria. Systematic reviews allowed for the definition of criteria for the selection of favorable sites, such as i) sites far from the coastline, ii) impermeable soils at their base to avoid contamination of aquifers, iii) use of remote sensing and geographic information system tools for continuous monitoring, iv) mitigation of possible contamination of ecosystems, v) planning the possibility of restoration (reforestation) and protection of the environment. In coastal zones, it is necessary to apply the ISWM approach to avoid landfill flooding and protect the marine environment, reducing rubbish and waste on beaches and oceans. Therefore, applying the circular economy in ISWM is critical to sustainability in coastal environments, with the planet's natural processes and variations due to climate change. [Display omitted] • Waste management is a key challenge for sustainability. • Personal and community education is fundamental to achieving ISWM. • ISWM is linked to the circular economy for sustainability. • Due to climate change, coastal zones must implement ISWM and waste recovery. [ABSTRACT FROM AUTHOR]

South Asia's coastlines are the most densely inhabited and economically active ecosystems have already begun to shift due to climate change. Over the past century, climate change has contributed to a gradual and considerable rise in sea level, which has eroded shorelines and increased storm-related coastal flooding. The differences in estuary water quality over time, both seasonally and annually, have been efficiently controlled by changes in stream flow. Assessment requires digitized analytical platforms to lower the risk of catastrophes associated with climate change in coastal towns. To predict future changes in an area's vulnerability and waste planning decisions, a prospective investigation requires qualitative and quantitative scenarios. The paper concentrates on the development of a forecasting platform to evaluate the climate change and waste water impacts on the south coastal region of India. Due to the enhancement of Digitization, a multi-model ensemble combined with manifold learning is implemented on the multi-case models influencing the uncertainty probability rate of 23% and can be ignored with desired precaution on the coastal environmental. Because Manifold Learning Analysis results cannot be utilized directly in wastewater management studies because of their inherent biases, a statistical bias correction and meta-feature estimation have been implemented. Within the climate-hydrology modeling chain, the results demonstrate a wide range of expected changes in water resources in some places. Experimental statistics reveal that the forecasted rate of 91.45% will be the better choice to reduce the uncertainty of climatic change and wastewater management. • Development of Multi-Objective Neighborhood Embedding Ensemble Strategy (NEES) to predict waste water and climate change impacts. • Manifold learning with metafeatures estimator model to forecast the temperature index and oxygen depletion. • Enhanced Coastal Management system with multi-parameter reliability model for South Asia Coastal region to safeguard the environmental eco-stability. • Manifold predictor models for waste water impact and climatic influence with maximum data samples with optimized cost function. [ABSTRACT FROM AUTHOR]

Coastal areas frequently face critical conditions due to the lack of adequate forms of land use planning, environmental management and inappropriate coastal risk management, sometimes leading to unexpected and undesired environmental effects. Risk management also involves cultural aspects, including perception. However, the acknowledgement of risk perception by stakeholders and local communities, as one of the social pillars of risk analysis, is often lacking. Starting from an overview of the risk concept and the related approaches to be addressed, the paper investigates the evolution of coastal risk management with a focus on the Italian case study. Despite the design and adoption of national policies to deal with coastal risks, coastal management still shows in Italy a fragmented and poorly coordinated approach, together with a general lack of attention to stakeholder involvement. Recent efforts in the design of plans aiming at reducing risks derived from climate change and mitigating their impacts (National Strategy on Climate Change Adaptation; National Climate Change Adaptation Plan; National Recovery and Resilience Plan activities) should be effective in updating knowledge about climate change risks and in supporting national adaptation policies. • Traditional coastal risk defense measures often lead to ineffective results. • Novel risk approaches are needed to manage the complexity of coastal issues. • Risk perception is a fundamental component in coastal risk management. • In Italy coastal management is fragmented and poor-coordinated. • It is important to involve stakeholder and society at large in management processes. [ABSTRACT FROM AUTHOR]

Coastal dunes are important habitats that also play an important role in coastal protection. In areas of high tourist activity, they have often been degraded by trampling and intensive use, resulting in a loss of ecological, aesthetic and protective values. As a result, several management actions have been taken to minimise dune degradation and enhance their recovery. One of these measures is the installation of elevated boardwalks and dune crossovers to regulate human access to the beaches. This paper quantifies and analyses the impact of the installation of boardwalks and dune crossovers on dune recovery in a highly touristic area in southern Portugal. This was done using aerial photographs taken before and 5–10 years after the implementation of the measures, and an effectiveness index was applied. The recovery observed was high to very high, ranging from 51% to 98% of the previously degraded dune. The areas with the oldest interventions showed an average recovery of 86% of the degraded area, while the most recently managed areas showed an average recovery of 69%. The high rate of recovery is mainly explained by the new habits developed by the population and tourists to access the beaches. Nevertheless, in some specific cases (i.e. where the use of the boardwalks requires a detour or where they end far from the beach) new degraded areas were observed, indicating the high relevance of the design of the boardwalks to the final recovery result. This work can serve as a basis for assessing the effectiveness of coastal management measures in any other coastal dune area with similar interventions. • Dune degradation in tourist areas can be reversed by simple management actions. • Elevated boardwalks contribute to dune recovery and encourage new habits. • New degraded areas can result from poor boardwalk design. [ABSTRACT FROM AUTHOR]

The brown mussel Perna perna is a valuable fishing resource, primarily in tropical and subtropical coastal regions. Because of their filter-feeding habits, mussels are directly exposed to bacteria in the water column. Escherichia coli (EC) and Salmonella enterica (SE) inhabit human guts and reach the marine environment through anthropogenic sources, such as sewage. Vibrio parahaemolyticus (VP) is indigenous to coastal ecosystems but can be harmful to shellfish. In this study, we aimed to assess the protein profile of the hepatopancreas of P. perna mussel challenged by introduced - E. coli and S. enterica - and indigenous marine bacteria - V. parahaemolyticus. Bacterial-challenge groups were compared with non-injected (NC) and injected control (IC) - that consisted in mussels not challenged and mussels injected with sterile PBS-NaCl, respectively. Through LC-MS/MS proteomic analysis, 3805 proteins were found in the hepatopancreas of P. perna. From the total, 597 were significantly different among conditions. Mussels injected with VP presented 343 proteins downregulated compared with all the other conditions, suggesting that VP suppresses their immune response. Particularly, 31 altered proteins - upregulated or downregulated - for one or more challenge groups (EC, SE, and VP) compared with controls (NC and IC) are discussed in detail in the paper. For the three tested bacteria, significantly different proteins were found to perform critical roles in immune response at all levels, namely: recognition and signal transduction; transcription; RNA processing; translation and protein processing; secretion; and humoral effectors. This is the first shotgun proteomic study in P. perna mussel, therefore providing an overview of the protein profile of the mussel hepatopancreas, focused on the immune response against bacteria. Hence, it is possible to understand the immune-bacteria relationship at molecular levels better. This knowledge can support the development of strategies and tools to be applied to coastal marine resource management and contribute to the sustainability of coastal systems. [Display omitted] • A total of 3805 proteins were found in the hepatopancreas of P. perna mussel. • Vibrio parahaemolyticus seems to be virulent and suppresses P. perna immune response. • E. coli and S. enterica triggered a general immune response against bacteria. • Proteins altered in response to all challenge-bacteria were vital for immune defense. • This study points out critical proteins against bacteria, promising for biotechnology. [ABSTRACT FROM AUTHOR]

This paper reports a scientific inquiry carried out within the management process of an exceptional accumulation of reeds and seagrasses that took place in December 2019 on Poetto beach (Cagliari, southern Sardinia, western Mediterranean). The magnitude of the event raised concern within the local community and tourism service providers especially for the compromised beach accessibility caused by this large amount of biomass. The scientific inquiry is carried out in support of coastal management, to assess the berm processes before the removal of the reed wracks decided by the local municipality. By means of a numerical approach, this work devotes special attention to the runup induced by storms in the presence of reed and seagrass deposits on a low-lying backshore. Field surveys reported relatively large conductivity parameters in the presence on reed and seagrass deposits. The numerical approach shows that the increased beach permeability can eventually mitigate coastal flooding induced by storms. These results highlight the ecosystem services provided by reed and seagrass wracks together with the implications for coastal protection and management. • Large permeability values were measured in areas with seagrass and reed deposits. • A numerical approach assesses runup and infiltration processes on a sandy beach. • Reed and seagrass wracks can mitigate flooding by increasing beach permeability. [ABSTRACT FROM AUTHOR]

In the face of uncertainties around coastal management and climate change, coastal engineering interventions need to be able to adapt to changing conditions. Nature-based solutions and other non-traditional, integrated interventions are gaining traction. However, system-based views are not yet embedded into coastal management strategies. Moreover, the differences in coastal interventions, ranging from hard ('grey') to nature-based ('green') infrastructure remain understudied. In coastal management it is therefore challenging to work with the grey-green spectrum of interventions with clarity and focus, and to produce results that can be evaluated. The objective of this paper was to examine whether there is a common understanding of: the characteristics and differences between grey and green infrastructure, where interventions sit on this spectrum, and the resilience of grey versus green infrastructure. We conducted an integrative literature review of the grey-green spectrum of coastal infrastructure. We examined 105 coastal protection case studies and expanded the double-insurance framework to ensure an integrative approach, looking at both external and internal factors of resilience. Our review showed that external factors are typically used to characterise the grey-green spectrum. However, although useful, they do not facilitate a holistic comparison of alternative interventions. The additional consideration of internal factors (response diversity, multifunctionality, modularity and adaptive, participatory governance) bridges this gap. The review showed that dikes, reefs, saltmarshes, sand nourishment and dunes span a wider segment of the grey-green spectrum than they are generally categorised in. Furthermore, resilient solutions for adaptation are unlikely to be exclusively engineered or natural, but tend to be a mix of the two at different spatial scales (micro, meso, macro and mega). Our review therefore suggests that coastal planners benefit from a more diverse range of options when they consider the incorporation of grey and green interventions in the context of each spatial scale. We propose that internal resilience should be accounted for when infrastructure options are comparatively evaluated. This consideration brings attention to the ways in which the grey-hybrid-green spectrum of infrastructure enhances value for people. • Examination of case studies along the grey-green spectrum of coastal protection. • Grey infrastructure increasingly incorporates ecological processes at varying scales. • Dikes, reefs, saltmarshes, sand nourishment and dunes span a wide segment of spectrum. • Internal resilience clarifies how infrastructure can enhance value for people. [ABSTRACT FROM AUTHOR]

This paper provides a thorough investigation of the effect of a top low-permeability (TLK) layer on transient saltwater intrusion dynamics prompted by water table fluctuations and sea level rise. Laboratory experiments were conducted on a 2D-sandbox and numerical simulations were performed using the SEAWAT code. Four cases were investigated, including a homogeneous case and three cases, where the top layer thickness (W top) was equal to 0.2H, 0.33H and 0.5H, respectively, where H was the aquifer thickness. The experimental and numerical results show that the toe length decreases linearly with increasing the thickness of the TLK layer. The results also suggest that lowering the permeability of the upper part of the aquifer causes faster saltwater removal process. The sensitivity analysis shows that decreasing the top layer permeability causes further reduction of the intrusion length. Nonetheless, the results evidence that this method yields relatively little reduction of the saline water intrusion length if the upper layer thickness is inferior or equal to a fifth of the total aquifer thickness, regardless of the permeability value of the top layer. The field-scale modelling results demonstrate that the performance of the TLK layer weakens noticeably as the hydraulic gradient decreases. The results show that the TLK layer achieved a maximum saltwater wedge reduction of 31% in the case where W top = 0.75H, which means that lowering the permeability of three fourths of the aquifer thickness only induced a toe length reduction by nearly a third of its original length. In addition to providing a quantitative analysis of SWI dynamics in bi-layered coastal aquifers, this study questions the performance and practicality of the artificial reduction of the upper aquifer permeability as a countermeasure for seawater intrusion control. • The impact of a top low-K layer on seawater intrusion was quantitively analysed. • The reduction in the intrusion length was linearly correlated with top layer thickness. • The low-K top layer only had noticeable reduction of SWI when its thickness is 50% the aquifer thickness or greater. • The low-K layer achieved a maximum saltwater wedge reduction of 31%. [ABSTRACT FROM AUTHOR]

One of the most used measures to counteract coastal erosion is beach nourishment. It has advantages with respect to the use of rigid structures that sometimes entail non desired impacts on the surrounding areas. However, beach nourishments are often unsuccessful, requiring frequent refills due to the use of sediments that are not suitable. In this paper, a methodological framework for increasing the probability of success of beach nourishment projects is presented. First, this framework consists of detecting potential borrowing areas, by analysing shoreline evolution and selecting the stretch that shows a more accretive character. Once the borrowing area has been identified, several sand extraction options are defined. The beach response (in terms of erosion and flooding) to each sand extraction alternative is analysed by using two numerical models, which simulate the hydro-morphodynamic patterns in the studied area. The numerical model results allow to find the best extraction alternative, which is that producing the least impact in the borrow area. As an example, the methodology is applied to a stretch of the Catalan coast (NW Mediterranean) to illustrate its potential. The proposed methodology shows to be a useful tool for helping coastal managers to optimize their available resources. • Beach nourishments are often unsuccessful due to the use of non-suitable sediments. • A methodological framework for selecting the best sediment sources for beach fills is developed. • The framework includes the identification of the borrowing area and the best sand extraction option. • The methodology is applied to a stretch of the Catalan coast (NW Mediterranean). • The methodology shows to be a useful tool for helping coastal managers to optimize their resources. [ABSTRACT FROM AUTHOR]