Modeling the Influence of Flood Mitigation Measures on the Vulnerability of Coastal Residential Construction

Coastal systems are characterized by high geophysical and biophysical sensitivity due to their special environment. The ecosystems along China's coast are especially vulnerable to the accelerated sea-level rise and associated multi-hazards such as storm surges and coastal flooding due to their low-lying topography, highly developed economy, and high-density population. To ensure a better management of China's coastal areas, it is crucial to develop adequate nationwide coastal vulnerability assessment models. This paperpresents our design and procedure of assessing the vulnerability of China's entire coast using eight factors. Techniques of geographic information systemand remote sensing were used to integrate the best available, spatially-disaggregated national data on critical impact elements. A comprehensive coastal vulnerability index(CVI) was then calculated by integrating the differentially weighted rank values of the variables. In the finalstep, the coastline was segmented into 4vulnerability levels: low, moderate, high and very high. The results generated from the segmentation show that 35% of the entire coast has high or very high vulnerability, mostly along Bohai Bay, the North Jiangsu coastal plain, the Yangtze River and the Yellow River Delta, and the western coast of Taiwan. The geographical distribution of the vulnerability grade proves to be reasonable. Findingsfurtherreveal that large amounts of land and population wouldbe vulnerable to inundation by coastal flooding from sea level rise and storm surge without effective measures. Finally, some suggestions are presented for decision makers and other concerned stakeholders to develop appropriate coastal zonemanagement and mitigation measures.

This chapter aims to deliver a brief overview of flood mitigation and protective measures at different scales within the catchment area and identify the main factors to be considered in flood risk management. It stands on an extensive literature review of the ongoing scholarly discourse on the topic. The main focus is given to novel approaches that are based on Nature-Based Solutions (NBS) principles, which are aligned with emerging public awareness not only towards cost-effective solutions but also towards sustainable proposals which go in harmony with the environment and natural landscapes. First, we provide a synopsis on the main aspects influencing the flood events such as Land-Use/Land Cover (LULC), topography, hydrometeorology, and hydraulics of the river. Later we included novel concepts such as ‘‘Sponge Cities”, Integrated Water Resource Management (IWRM), and the Sustainable Urban Drainage System (SuDS) as examples of mitigation practices which simultaneously integrate cost-effective non-structural and structural mitigation measures. Further on, we give some insight on the recommendations on the most pressing research questions and conclude the key issues to be considered in the flood risk management concerning NBS approaches. As a result, the study highlights two among many recommendations as to the foremost crucial ones. First, the flood risk reduction agendas must adopt a spatially comprehensive and cross-scale approach while considering flood events. Finally, natural properties of the context such as LULC, topography, hydrometeorology, and hydraulics must be considered simultaneously to utilise the full natural capacity of the context in flood risk mitigation.

A framework for coastal flood hazard assessment under sea level rise: Application to the Persian Gulf

Low-lying coastal areas are highly vulnerable to flood hazards, especially under the influence of global warming, and the possibility of compound floods is often much greater than that of individual floods. Understanding the probability of these compound events and the processes that drive them is essential for mitigating the impacts of coastal high-risk areas. Here we use a new simplified physical solver SFINCS model (Super-Fast INundation of CoastS), to computationally efficiently calculate compound floods in coastal areas due to fluvial, pluvial and storm surge driven processes. At the same time, a variety of climate scenarios are considered for the prediction of potential future compound flood patterns. We demonstrated in our application case in Shanghai, China, that the model can simulate a combination of fluvial, pluvial, and storm surge driven floods well. Our results show that the combined effects of future climate change on coastal compound flood hazards will significantly increase the extent of flood hazards, obviously increasing the level of risk at low-risk areas and requiring an integrated response to the consequences of future compound floods. This research has important implications for the assessment of compound flood risk in coastal areas and for climate-resilient flood management.

Flood risk management comprises risk assessment through robust modeling and mitigation through measure implementation. Decision-making on mitigation measures is complicated by the plethora of criteria, stakeholder influence, implementation scale and financial constraints. Multi-criteria decision-making (MCDM) methods have emerged as valuable tools in this context, allowing for the systematic integration of diverse factors and perspectives. Nonetheless, MCDM applications in mitigation measure ranking remain challenged by the lack of informed evaluation of criteria and the diversity of measures at local reach-scale. This work aims to develop a comprehensive methodology for prioritizing flood mitigation measures. An application is conducted on a Mediterranean catchment, the Ostouane River (144 km2), Northern Lebanon. The approach involves identifying 11 intervention reaches, proposing 38 mitigation measures, and evaluating a set of 7 primary criteria decomposed into 19 multidimensional secondary criteria. We introduce criteria of effectiveness, technical, exposure and vulnerability in addition to the commonly used criteria of environmental impact, socio-economic impact, and cost. The criteria are evaluated based on qualitative and quantitative inputs derived from the literature, surveys, questionnaires, hydrological and hydraulic modelling. The TOPSIS model is employed using 6 subjective stakeholder-driven weighting methods and 6 data-driven objective weighting methods. The methodology is evaluated through a sensitivity analysis that emphasizes on the importance of measure effectiveness, environmental impact, and cost criteria in the model. Results show that subjective weighting methods tend to prioritize structural measures at downstream areas with high-value assets, while objective methods show a more balanced distribution of measures, including green solutions and upstream reaches. The total cost of the 10 prioritized measures using subjective methods is 20% higher than that of objective methods. However, the specific choice of a weighting method can imply a substantial variation in total implementation and maintenance cost. Essentially, the choice of weighting method in MCDM can significantly alter the resulting strategies and management of risk. This contrast highlights the need for policymakers to develop flexible, adaptive strategies that balance immediate protection needs with long-term sustainability goals. Overall, this work provides a novel approach for integrated flood risk management based on adapted local-scale and informed decision-making.

<p><em>Posidonia oceanica </em>(L.) Delile meadows are considered as the most productive ecosystems of the Mediterranean basin, sequestering and storing significant amount of blue carbon in their rich organic sediments and in their living and non-living biomass and these meadows are identified as a priority habitat type for conservation under the Habitat Directive (Dir 92/43/CEE). Despite the importance of the ecosystem services it provides, this habitat is disappearing at a rate four times as high as that of terrestrial forests, experiencing an alarming reduction due to the impacts of human activities in coastal areas, especially in the north-western side of the Mediterranean Sea. To face this issue, the SeaForest Life project foresees the quantification of carbon deposits and their rate of change related to habitat degradation specifically focusing on the effects caused by boat’s anchors and moorings. The project is realized in the Archipelago of la Maddalena National Park, the Asinara National Park and the Cilento, Vallo di Diano and Alburni National Park, for which ad hoc management plans of mooring are going to be adopted to reduce the impact of this practice on the seagrass meadows. As a first step, an updating of habitat 1120*’s cartography in each of the Marine Protected Areas engaged in the project have been fulfilled, using high definition multispectral imagery. Furthermore, monitoring of the areas with the highest attendance of the anchorages was carried out through the use of medium resolution satellite multi-spectral images using the infrared band, to identify and quantify the degradation and the state of conservation of the <em>P.oceanica</em> meadows present in the investigated areas. The updated cartography has been used to implement the InVEST Coastal Blue Carbon (CBC) which attempts to predict the sequestration, storage and, when degraded, the emissions of carbon by coastal ecosystems, so representing a useful tool for the analysis of the ecological and economic effects of the degradation processes (boats anchoring) and mitigation measures (anchor management plan and eco friendly moorings). Up to now, the InVEST-CBC model has estimated a CO<sub>2</sub> loss due to boats anchoring equal to 2300 tCO<sub>2</sub>/year, using stock and flow data in soil and biomass obtained from the results of the Life Blue Natura project and<em> P. oceanica</em> samples collected in the Cilento National Park. In the future, the results of the model will be improved with data collected in the other two project areas, also through the use of innovative instrumentation. Moreover, the scenarios with the implementation of the mooring management plans will be analyzed in the three study areas. The dataset obtained by the model is being used to define a standard protocol for the estimation of CO<sub>2</sub> fixation by <em>P. oceanica </em>meadows in the Mediterranean Sea. Such protocol will be fundamental for the realization of a national IT-based platform for a voluntary based carbon market to sell and acquire the carbon credits generated by the SeaForest Life project activities, to be extended to all the Mediterranean countries and to be scaled up to new protected marine areas.</p>

The three dimensional hydrodynamic pollutant transport model IDOR3D was used to simulate the nearshore current structure and pollutant dispersion from various sources. These sources can be municipal or industrial discharges and if are not properly designed will eventually cause environmental problems in the coastal areas. The inflows from sewage treatment plants and creeks affect the current structure within a small distance from the source. Their influence was studied in a high resolution of 100 m model in map sections E1 to E4 (Fig. 1). For the circulation of the northern coasts of Crete were the major urban centers are located, a grid size of 2 km was used. Local meteorological stations provided the wind speed and direction. The bathymetric files and coastlines were obtained from hydrographic digital files and the Digital Bathymetric Model (DBM) produced the gridded data obtained via GIS. Additional information from the Digital Elevation Model (DEM) of Crete with the aid of GIS technology can provide information of point sources discharging at the exit of watersheds in the near shores of the island. Further watershed analysis (hydrological/hydraulic/ pollutant concentration analysis) for rain events provides the pollutographs of ephemeral creeks discharging to the coastal areas that are used as input to IDOR3D. By employing different receiving water conditions (isothermal and stratified) and pollutant source conditions, simulations were performed in the areas E3 to E4 of Fig. 1. The bay in map section E4 was used to simulate the fate of a pollutant discharged over a four-hour period from an ephemeral creek under sea isothermal conditions and a 5m/s NW wind. The environmental impact on the nearshore area and mitigation measures are discussed. The bay in the map region E3 was used to examine the behavior of a contaminant discharged continuously into the bay from a submerged outfall source at two different locations (a) at 10m deep, positioned 250m offshore and (b) at 27 m depth positioned 2 km offshore, with the purpose to analyze the movement of the contaminant with respect to the island and the relative impact to nearshore areas. Concentration time series for a continuous conservative pollutant released with a concentration of 1000ppm into Chania bay under sea isothermal conditions and a 5m/s NW wind for the case (b), are shown in Fig. 2. In the case (a) the contaminant will dispersed between the island and the mainland shallow passage which will potentially cause environmental problems in a highly touristic area. The dilution is less under stratified conditions due to the buoyant forces of the pollutant generated by temperature and density differences, which reduces the amount of mixing due to the contaminant moving quickly to the surface. Complete results from all the cases will be presented in the conference.

IntroductionCoastal erosion is widely distributed globally, with sandy coasts being particularly prominent, causing significant economic losses to coastal areas. This study focuses on the coastal areas of Liaoning Province, China, which represent typical sandy beach erosion.MethodsBased on the assessment of coastal erosion disaster losses, a multivariate variable-weight combination prediction model is utilized to predict the losses caused by coastal erosion disasters, providing an effective mathematical modeling approach for predicting such losses. Furthermore, the cluster analysis method is employed to delineate vulnerability risk zones for coastal erosion along the Liaoning Province coast.Results and discussionThe research findings indicate the following: (1) From 2023 to 2025, the losses due to coastal erosion disasters in Liaoning Province are projected to decrease significantly from a scale of 36 million RMB yuan to 5 million RMB yuan; (2) Based on the magnitude of disaster vulnerability risk, the coastal areas of Liaoning Province are categorized into four risk zones: high-risk zones (Jinzhou District), moderately high-risk zones (Zhuanghe City, Wafangdian City, Ganjingzi District), medium-risk zones (Lvshunkou District, Bayuquan), and low-risk zones (Gaizhou City, Suizhong County, Xingcheng City). Recommendations are proposed accordingly: (1) Effective measures should be implemented to mitigate the losses incurred by coastal erosion on land, buildings, infrastructure, agricultural output; (2) In the selection of disaster prevention and control measures,economic factors should be carefully considered in line with the specific circumstances of the losses. Specifically, the economic efficiency of disaster prevention and mitigation measures should be taken into account; (3) Precise efforts should be made to implement coastal erosion disaster prevention and control measures in different regions.

At present porcelain and glass insulators are used for overhead power lines in Sri Lanka. Salt contamination on insulators of coastal lines assists leakage currents to passing over the insulator surface and cause insulator flashing over. Frequent power outages due to flashing over of insulators on overhead power lines are common in coastal areas and it reduces the reliability of the power system considerably. It has been observed that this problem is very severe in costal lines in dry zone of Sri Lanka especially in Puttalam, Mannar and Jaffna areas. Partial blackout caused by flashing over of insulators on 220kV transmission line running closer to the sea and across the Kalpitiya lagoon from Norochcholai coal plant to Veyangoda switching station shows the severity of this problem. Therefore it is timely requirement to review the insulator selection criteria for overhead power lines to find out mitigation measures against the flashing over of insulators due to marine pollution. This paper describes the mechanism of flashing over of insulators due to marine pollution and highlights the limitations of the presently following electrical standards for insulator selection based on field measurements and maintenance experience. It is emphasized that the most successful method that can be employed to determine the ideal insulator out of insulators made of different materials and of different shapes is to verify their performance by conducting long term field measurements at the exact environment. Apart from that the existing practices applied on distribution network to minimize insulator flashing over is evaluated technically and financially in order to identify the best solution. Application of new technology such as adaptation of polymeric insulators, insulator coating materials and applicable online insulator washing techniques are also investigated. The importance of type test reports named as artificial pollution tests to understand the pollution immunity of insulators is also discussed. The value of establishing insulator field testing stations in problematic areas is strongly recommended and the test techniques applicable in field evaluation of insulator performance are briefly explained. ENGINEER, Vol. 47, No. 02, pp. 57-73, 2014

Assessment of socio-economic vulnerability under sea level rise coupled with storm surge in the Chongming County, Shanghai

ABSTRACTHigh-energy events are increasingly frequent in Northeast Brazil. Of these we mention undertow between December and April, causing several impacts on coastal areas. Therefore, the aim of this chapter is to establish the evolution of the Aquiraz city's coast line in the period 1958 to 2014 and from 2009 to 2014 to identify erosion and silting trends, the natural and anthropogenic tensioners associated with these procedures. In the methodology, the maximum flood line was chosen as an indicator of advance or retreat of shoreline, identified in QuickBird and Landsat satellite images and aerial photographs. The program DSAS was applied to evolution of the coastline in the last 56 years. It was found that the coast is in progressive erosive phase. Between 1958 - 2014, Japan's AEPR from -0.07 to -1.29 m / year and Porto das Dunas from -0.29 to -2.61 m / year. The reflection of this human action coincides with the period of greatest retreat of the coastline throughout the area. The frontal dunes are arranged discontinuously, are absent in some places due to the occupation of tents and fixed constructions. Thus this coastal line study was an essential tool to deepen regarding the local dynamics in order to suggest further mitigation measures by generating new data considering the occupation advancement and climate and oceanographic changes.

High-resolution approach to quantify the impact of building-level flood risk mitigation and adaptation measures on flood losses at the community-level

Six operators on the Norwegian Continental Shelf (NCS) have joined the "DREAM Charter" project to further develop a unified numerical environmental risk-based assessment model for evaluation of environmental risks associated with regular discharges from the petroleum industry in offshore (e.g. produced water and drilling discharges,) and coastal sea areas (land terminals). The operators participating in this project are ENI Norway, Total E&P Norway, BP, ConocoPhillips Norway, Statoil and Det Norske. The environmental risk method applied is following a substance based approach, and is representing one of the two approaches adopted in the OSPAR recommendation for a risk-based approach to the management of produced water discharges from offshore installation (OSPAR Recommendation 2012/5). The environmental risk framework follows principles of environmental risk assessment in use in EU (e.g. ECHA – Technical Guidance documents) and US (US-EPA Guidance on risk assessment). The numerical model predicts the exposure to substances or stressors present in regular discharges in the receiving environment, expressed as the PEC (Predicted Environmental Concentration). The characterisation of environmental risk of regular discharges is based on the PEC: PNEC ratios for the individual substances. The PNEC (Predicted No Effect Concentration) is the concentration of a substance or environmental stressor which adverse effects on the ecosystem and its organisms will most likely not occur. To arrive at a single overall risk including multiple substances in the EIF methodology, the individual PEC: PNEC ratios are combined, based on species sensitivity distributions (SSDs), estimating the fraction of species potentially affected (PAF) at a specific exposures concentration. The overall risk can be assessed using multi-substance potentially affected fraction of species (msPAF). The msPAF is a combination of the individual PAF values for all substances and stressors in the discharge. The msPAF < 5% level is used as a cut off criterion, assuming that risk is inacceptable if more that 5% of the species are exposed above their chronic no observed effect concentration. Because this method combines risks of different substances or stressors, the contribution to risk from every single substance (stressor) can also be derived. This allows selection of mitigation measures with the highest risk reduction potential. The risk-based management model allows estimation of environmental risks both in water column and in sediments from exposure to toxic (e.g. chemical substances) and nontoxic stressors (e.g. suspended particles, sediment burial). The model calculates the "Environmental Impact Factor" (EIF), which characterizes the overall potential impact on the marine environment in terms of recipient water volume and sediment surface area exceeding generic threshold values effects for toxic and nontoxic stressors. The numeric risk-based model and the EIF concept have been applied by operators on the NCS the last decade to achieve the goal of "zero harmful discharges" to the offshore environment from regular discharges like produced water and drilling discharges. Identification of the potentially most harmful substances in discharges enables the operator to select the most environmental beneficial, optimal and cost-efficient mitigation measure to reduce the risk or potential impact of discharges on the marine environment. This paper describes briefly the model framework of the environmental risk approach and the EIF concepts applied by operators for different regular discharges on the NCS. Some examples of use of the different EIFs are also illustrated. Furthermore, the current application of the model system and the plan for developments through the "DREAM Charter" joint industry project, are also briefly described.

Impact assessment of a marine and coastal protected area on fishing households through a counterfactual approach. A Senegalese case study (West Africa)

<p>Coastal areas are socially, economically, and environmentally intensive zones. Their risk to various natural coastal hazards like coastal flooding, erosion, and storm surges has increased due to climate-induced changes in their forcing agents or hazard drivers (e.g. sea-level rise). The increased exposure (e.g. dense population living near the coast) and vulnerability (e.g. insufficient adaptation) to these hazards in the coastal areas have complicated the adaptation challenges.</p><p>Thus, monitoring coastal hazards is essential to inform suitable adaptation to increase the climate resilience of the coastal areas. In monitoring coastal climate hazards to develop coastal climate resilience, both the forcing agents and the coastal responses should be observed.</p><p>As coastal monitoring is often expensive and challenging, creating a database through a systematic analysis of low-cost sensing technologies, like UAV photogrammetry for monitoring the hazards and their drivers would be beneficial to the stakeholders. Real-time information from these low-cost sensors in complement to the existing institutional sensors will facilitate better adaptation policies including the development of early warning support for building coastal resilience. In addition, it would also provide a valuable dataset for validating coastal numerical models and providing insights into the relationship between these hazards and forcing agents. Additionally, such low-cost sensors would also create opportunities for engaging citizens in the data collection process, for efficient data collection, and increasing scientific literacy amongst the general public. For instance, in the Sensing Storm Surge Project (SSSP), citizen science was used to collect technical data to characterise estuarine storm surges, generating data useable in peer-reviewed Oceanography journals. Coastal areas show complex morphological changes in response to the forcing agents over a wide range of temporal and spatial scales. Thus, monitoring the hazards with a sufficient temporal and spatial resolution is imperative to distinguish the changes in these hazards/drivers due to climate change from natural variability. This will not only help address the response strategies to these hazards but also adjust these response strategies according to the changing vulnerability of a particular region.</p><p>The database of the low-lost sensors thus created is in no way exhaustive since those have been retrieved through a certain combination of keywords in databases like Sciencedirect, Web of Science, and Scopus, nonetheless it is useful as these are the latest low-cost sensors available to monitor the major coastal hazards in the vulnerable coastal regions.</p>