scholarly journals A Preliminary Assessment of Coastal Vulnerability For Ngazidja Island, Comoros Archipelago, Western Indian Ocean

Author(s):  
Avouca Mahamoud ◽  
Maher Gzam ◽  
Nadjim Ahmed Mohamed ◽  
Soulé Hamidou Hamada ◽  
Mabrouk Montacer

Abstract In previous studies, an emphasis on the particular vulnerability of small island states to future sea-level rise and the intensity of increasing storm surges has been discussed. This preliminary assessment develops a Coastal Vulnerability Index (CVI) along the 202 km long coastline of Ngazidja Island (formerly Grande Comore, Comoros Archipelago), using fieldwork, remote sensing, and geographic information system tools (GIS). The CVI considers five structural variables: (a) geology, (b) geomorphology, (c) topography, (d) shoreline change, and (e) shoreline exposure). It also considers three physical process variables: (f) relative sea-level rise, (g) significant wave height, and (h) mean tide range). The land-use variable was added in this analysis to highlight the human asset exposure in the surrounding areas. Each variable was ranked based on local physical and hydrodynamic conditions and their vulnerability contribution to sea-level rise. The CVI was computed in 270 sections. According to the vulnerability index, approximately 57.5% of the coastline is under low and moderate vulnerability. High and very-high vulnerabilities refer specifically to beaches and shores with old volcanic lava flows located mainly in the northern, northeastern, and southeastern parts of the island, approximately 42.5% of the coastline. The lowest value of CVI is 9.2 on high, rocky cliffs and the highest value is 160 on beaches. This vulnerability partition along the coastline is consistent with in situ indicators of coastal erosion and flooding. In a sea-level rise context, it is of prime importance to integrate coastal vulnerability maps with planning and sustainable management of the coastal zone.

2018 ◽  
Vol 7 (3.14) ◽  
pp. 176 ◽  
Author(s):  
Fazly Amri Mohd ◽  
Khairul Nizam Abdul Maulud ◽  
Othman A. Karim ◽  
Rawshan Ara Begum ◽  
Md Firoz Khan ◽  
...  

Climate change interacts in a different way with varieties of human activities and other drivers of change along coastlines. Sea level rise (SLR) is one of the major impacts of global warming. Changes in climate extremes and SLR may impact the critical infrastructures such as coastal road, jetty and chalets as well as the local community. The population and assets exposed to coastal risks will increase significantly due to population growth, economic development and urbanization in the future. As most of the cities in Malaysia are situated near the coast, immediate actions are needed to minimize the undesired outcome due to the SLR. The main objective of this study is to identify physical variables that may have impacts on the coastal area, thus develop a coastal vulnerability index (CVI) for the East Coast of Peninsular Malaysia. Seven (7) physical variables have been identified to assess the CVI that consists of geomorphology, coastal slope, shoreline change rate, mean significant wave height, mean tidal range, relative sea level rate and land use. A comprehensive CVI was obtained by integrating the differential weighted rank values of the variables. The outcome of this study is useful as a tool for coastal disaster management.  


SINERGI ◽  
2019 ◽  
Vol 23 (1) ◽  
pp. 17
Author(s):  
Mawardi Amin ◽  
Ika Sari Damayanthi Sebayang ◽  
Carolina Masriani Sitompul

Anyer Beach is one of the famous tourist destinations. In addition to tourist destinations, the Anyer beach also has residential and industrial areas. In managing coastal areas, a study of vulnerability is needed due to threats from sea level rise, abrasion/erosion and also high waves that can damage infrastructure and cause losses. The research method is to collect data of hydro-oceanography, coastal vulnerability index calculates (Coastal Vulnerability Index). The coastal vulnerability index is a relative ranking method based on the index scale physical parameters such as geomorphology, shoreline change, elevation, sea level rise, mean tidal, wave height. On the results of the analysis of the criteria of vulnerability based on the parameters of geomorphology in the category of vulnerable with scores of 4, shoreline change in the category of vulnerable with a score of 4, the elevation in the category of extremely vulnerable with scores of 5, sea level rise into the medium category with a score of 3, mean tidal in the category less susceptible with a score of 2, the wave height is very vulnerable in the category with a score of 5. The variable that most influences the vulnerability of Anyer Beach is elevation and wave height.


2014 ◽  
Vol 71 (4) ◽  
Author(s):  
Gill J. Ainee ◽  
A.M. Anwar ◽  
S. Omar K

Climate change has brought about many threats to the ecosystem by inducing natural hazards, particularly sea level rise. Coastal areas then are subjected to many adverse effects of sea level rise, hence posing a risk to the safety of the coastal population, resources and assets. As part of the mitigation and adaptation measures against these effects, the Coastal Vulnerability Index (CVI) was implemented by many coastal regions. The CVI is an index-based tool to map the risks related to coastal changes. In Malaysia, the practice of CVI is still in its initial stages. Whereby, the Department of Irrigation and Drainage (DID) Malaysia had earlier carried out two pilot projects on CVI. The first is located at Tanjung Piai and the second at the west coast of Pulau Langkawi. This paper reviews the definition and concept of CVI. An alternative implementation approach of CVI in Malaysia is also discussed.


Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2169
Author(s):  
Dimitrios Vandarakis ◽  
Ioannis P. Panagiotopoulos ◽  
Vassiliki Loukaidi ◽  
Georgios-Angelos Hatiris ◽  
Paraskevi Drakopoulou ◽  
...  

The foreseeable acceleration of global sea level rise could potentially pose a major threat to the natural charm and functional integrity of the world-renowned tourist coastal attractions of Rhodes Island, as a result of the anticipated increasing frequency of flooding and erosion events. Hence, this study aims to determine the most vulnerable segments (in terms of physical impact) of the Rhodes coastline through the widely accepted coastal vulnerability index (CVI), applying a combination of well-known, broadly used approaches and methods. The frequency distribution of the current CVI along the island’s coastline suggests a rather worrying high to very high vulnerability of 40%. In addition, a CVI projection to the end of the 21st century (based on the Intergovernmental Panel on Climate Change predictive scenarios) indicates an enhancement of the total vulnerability by 48%, mainly focused on the majority of the western coastline. Hence, a considerable number of popular coastal destinations in the island shall remain under unignorable threat and, therefore, coastal managers and decision-makers need to hatch an integrated plan to minimize economic and natural losses, private property damage and tourism infrastructure deterioration from flooding and erosion episodes, which will most likely be intensified in the future.


2014 ◽  
Vol 14 (12) ◽  
pp. 3317-3329 ◽  
Author(s):  
Z. N. Musa ◽  
I. Popescu ◽  
A. Mynett

Abstract. An evaluation of vulnerability to sea level rise is undertaken for the Niger Delta based on 17 physical, social and human influence indicators of exposure, susceptibility and resilience. The assessment used geographic information systems (GIS) techniques to evaluate and analyse the indicators and the index of coastal vulnerability to floods, if sea level rise conditions are occurring. Each indicator value is based on data extracted from various sources, including remote sensing, measured historical data series and a literature search. Further on, indicators are ranked on a scale from 1 to 5 representing "very low" to "very high" vulnerability, based on their values. These ranks are used to determine a similar rank for the defined coastal vulnerability index (CVSLRI). Results indicate that 42.6% of the Niger Delta is highly vulnerable to sea level rise, such areas being characterised by low slopes, low topography, high mean wave heights, and unconfined aquifers. Moreover, the analysis of social and human influences on the environment indicate high vulnerability to sea level rise due to its ranking for type of aquifer, aquifer hydraulic conductivity, population growth, sediment supply and groundwater consumption. Such results may help decision makers during planning to take proper adaptive measures for reducing the Niger Delta's vulnerability, as well as increasing the resilience to potential future floods.


2014 ◽  
Vol 2 (8) ◽  
pp. 5213-5245
Author(s):  
Z. N. Musa ◽  
I. Popescu ◽  
A. Mynett

Abstract. An evaluation of vulnerability to sea level rise is undertaken for the Niger delta based on 17 physical, social and human influence indicators of exposure, susceptibility and resilience. The assessment used GIS techniques to evaluate and analyse the indicators and the index of coastal vulnerability to floods, if sea level rise conditions are occurring. Each indicator value is based on data extracted from various sources including remote sensing, measured historical data series and literature search. Further indicators are ranked on a scale from 1 to 5 representing "very low" to "very high" vulnerability, based on their values. These ranks are used to determine a similar rank for the defined coastal vulnerability index (CVSLRI). Results indicate that 42.2% of the Niger delta is highly vulnerable to sea level rise; such areas been characterized by low slopes, low topography, high mean wave heights, and unconfined aquifers. Moreover the analysis of social and human influences on the environment indicate high vulnerability to sea level rise due to its ranking for type of aquifer, aquifer hydraulic conductivity, population growth, sediment supply and groundwater consumption. Such results may help decision makers during planning, to take proper adaptive measures for reducing Niger Delta's vulnerability, as well as increasing the resilience to potential future floods.


Author(s):  
Carolina Rocha ◽  
Carlos Antunes ◽  
Cristina Catita

The sea level rise, a consequence of climate change, is one of the biggest challenges that countries and regions with coastal lowland areas will face in the medium term. This study proposes a methodology for assessing the vulnerability to sea level rise (SLR) on the Atlantic coast of Portugal mainland. Some scenarios of extreme sea level for different return periods and extreme flooding events were estimated for 2050 and 2100, as proposed by the European Union Directive 2007/60/EC. A set of physical parameters are considered for the multi-attribute analysis technique implemented by the Analytic Hierarchy Process, in order to define a Physical Vulnerability Index fundamental to assess coastal vulnerability. For each SLR scenario, coastal vulnerability maps, with spatial resolution of 20 m, are produced at national scale to identify areas most at risk of SLR, constituting key documents for triggering adaptation plans for such vulnerable regions. For 2050 and 2100, it is estimated 903 km2 and 1146 km2 of vulnerable area, respectively, being the district of Lisbon the most vulnerable district in both scenarios. Results are available through a Web Map Service, for Portuguese public entities, and through a web map viewer for public and communities in general.


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 360 ◽  
Author(s):  
Carolina Rocha ◽  
Carlos Antunes ◽  
Cristina Catita

Sea level rise, a consequence of climate change, is one of the biggest challenges that countries and regions with coastal lowlands will face in the medium term. This study proposes a methodology for assessing the vulnerability to sea-level rise on the Atlantic coast of mainland Portugal. Some scenarios of extreme sea levels for different return periods and extreme flooding events were estimated for 2050 and 2100, as proposed by the European Directive 2007/60/EC. A set of physical parameters are considered for the multi-attribute analysis based on the Analytic Hierarchy Process, in order to define a Physical Vulnerability Index fundamental to assess coastal vulnerability. For each sea-level rise scenario, coastal vulnerability maps, with a spatial resolution of 20 m, are produced at a national scale to identify areas more vulnerable to sea-level rise, which are key elements for triggering adaptation plans for such vulnerable regions. For 2050 and 2100, it is estimated that there will be 903 and 1146 km2 of vulnerable areas, respectively; the Lisbon district being identified as the most vulnerable in both scenarios. Results are available as a Web Map Service for the Portuguese public entities, and through a web map viewer for the public and communities in general.


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