Flood Vulnerability Assessment of Kali Welang Floodplain by Using AHP-Based Methods

Floods occur almost every year in a number of areas in the floodplain of Kali Welang. The floods have caused loss of materials and lives. Assessment of the vulnerability is essential for policy making in non-structural treatment of floods. The objective of this paper is to compute and elaborate the flood vulnerability index in local scale to assess conditions that affect the magnitude of flood hazards. This study identifies and evaluates the Flood Vulnerability Index (FVI) of an area by considering the factors of area’s exposure to floods, flood susceptibility, and flood resilience. The Analytic Hierarchy Process (AHP) is used to formulate the weights of each component. The values of the components were collected from interviews with policy makers from relevant governmental agencies. The inputs for the AHP were collected from the respondents in a questionnaire survey. This study selected 18 relevant indicators. The FVI results show very high vulnerability in local scale in one village and high vulnerability in other six villages. The results of this study can be used to construct non-structural strategies in flood mitigation by enhancing community’s resilience toward the flood. In addition, the results can be used for policy making process in spatial urban planning.

Integration of earth observation and census data for mapping a multi-temporal flood vulnerability index: a case study on Northeast Italy

Climate sciences foresee a future where extreme weather events could happen with increased frequency and strength, which would in turn increase risks of floods (i.e. the main source of losses in the world). The Mediterranean basin is considered a hot spot in terms of climate vulnerability and risk. The expected impacts of those events are exacerbated by land-use change and, in particular, by urban growth which increases soil sealing and, hence, water runoff. The ultimate consequence would be an increase of fatalities and injuries, but also of economic losses in urban areas, commercial and productive sites, infrastructures and agriculture. Flood damages have different magnitudes depending on the economic value of the exposed assets and on level of physical contact with the hazard. This work aims at proposing a methodology, easily customizable by experts’ elicitation, able to quantify and map the social component of vulnerability through the integration of earth observation (EO) and census data with the aim of allowing for a multi-temporal spatial assessment. Firstly, data on employment, properties and education are used for assessing the adaptive capacity of the society to increase resilience to adverse events, whereas, secondly, coping capacity, i.e. the capacities to deal with events during their manifestation, is mapped by aggregating demographic and socio-economic data, urban growth analysis and memory on past events. Thirdly, the physical dimension of exposed assets (susceptibility) is assessed by combining building properties acquired by census data and land-surface characteristics derived from EO data. Finally, the three components (i.e. adaptive and coping capacity and susceptibility) are aggregated for calculating the dynamic flood vulnerability index (FVI). The approach has been applied to Northeast Italy, a region frequently hit by floods, which has experienced a significant urban and economic development in the past decades, thus making the dynamic study of FVI particularly relevant. The analysis has been carried out from 1991 to 2016 at a 5-year steps, showing how the integration of different data sources allows to produce a dynamic assessment of vulnerability, which can be very relevant for planning in support of climate change adaptation and disaster risk reduction.

Physical flood vulnerability assessment of buildings in Kota Bharu, Malaysia: an indicator-based approach

Purpose The purpose of this paper is to introduce a geospatial approach for buildings flood vulnerability assessment using an indicator-based method (IBM) to support flood risk assessment and mapping of physical elements at risk in Kota Bharu District, Kelantan, Malaysia. Design/methodology/approach The study developed an indicator-based approach to undertake physical flood vulnerability assessment of buildings. The approach takes into consideration flood hazard intensity, building characteristics and structures surrounding the environment as factors that influence flood vulnerability. The aggregation of the total flood vulnerability index is carried out in a geographic information system (GIS) environment. Findings The results provide a spatial representation of buildings flood vulnerability index in Kota Bharu Malaysia, and the degree of expected vulnerability is expressed on a scale between 0 to 1 (low damage to total damage). Mapping flood vulnerability index of buildings should be considered in future flood mitigation and evacuation planning. Originality/value Unlike other indicator-based methods (IBMs) developed for physical flood vulnerability assessment, in the current study, hazard intensity has been considered and incorporated in the physical flood vulnerability model.