Vulnerability Mapping for Disaster Assessment Using ArcGIS Tools and Techniques for Mumbai City, India

Transcription

1 Vulnerability Mapping for Disaster Assessment Using ArcGIS Tools and Techniques for Mumbai City, India Reshma Raskar-Phule Assistant Professor, Department of Civil Engineering, Sardar Patel College of Engineering, Andheri (w), Mumbai , India. Also, Research Scholar, Department of Civil Engineering, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai , India.

2 Overview Hazard, Vulnerability and RISK Analysis (HVRA) - Terminologies on Disaster Risk Reduction - (UNISDR 2009) Vulnerability Assessment ArcGIS - Data Collection - Data Analysis - Mapping Vulnerability- Hazard Maps

3 Overview Mumbai City sqkm area 11.9 million population Vulnerable to natural disasters Data Collection Qualitative data Primary and secondary sources Spatial data location and geometry ArcGIS - Open Street Map (OSM) 721 data grid points generated Mumbai Maharashtra Location Map of Mumbai city

4 Data and Technology used Spatial Data Download OSM Data Download Source: ArcGIS

5 Methodology Spatial Data Analysis: Grid Layer - 1 km X 1 km - - Clipped with digitized Mumbai boundary layer - Exact area of each grid - Calculate geometry tool Vulnerability Index (VI) VI i = (V i V max ) (V max V min ) - VI i is the vulnerability index for the indicator pertaining to the i th grid, - V i is the vulnerability value of the i th grid. - length in case of transportation infrastructure and - count of the indicators within a grid in case of critical infrastructure - Vmax and Vmin are the maximum and minimum vulnerability values of all the grid cells 1 km X 1 km Grid layer Clipped with digitized Mumbai Boundary layer

6 Methodology 1. Layers - Infrastructure indicators - Transportation indicators - railways, aeroways, roadways and bridges - Critical facilities indicators - schools, hospitals, important Government offices, hotels, fire stations, heritage structures, railway stations, bus stations and depos and educational institutions 2. Intersect Grid Layer and Indicator layer Number of indicator in each grid is counted using the spatial join tool of Overlay from the ArcToolbox Length of the indicator in each grid is calculated using the clip and intersect tools from the ArcToolbox

7 Methodology Transportation Infrastructure vulnerability using ArcGIS 1) Infrastructure layer is imported into GIS; 2) Length of each indicator is contained in the attributes table 3) The infrastructure indicator segments from the attribute table are selected which fall within and intersect a particular grid 4) The statistics option from the length field in the attribute table options is selected 5) The program calculates the sum of lengths and display them in that particular grid 6) The values are stored in a table and finally used for determining the vulnerability indices. Vulnerability grid map for Roads

8 Results Vulnerability grid maps Railways Educational Buildings Vulnerability index of each grid is scaled from 0 to 1. Vulnerability Vulnerability Infrastructure density Level Index (VI) No 0 No infrastructure Low 0.25 Low infrastructure Moderate 0.5 Moderate infrastructure High 0.75 Dense infrastructure network Very High or Critical Vulnerability Classes based on VI 1 Very dense infrastructure network

9 Results Hazard x Exposure x Vulnerability = Disaster Risk X X = Hazard Exposure Vulnerability Risk

10 Conclusion ArcGIS can be a powerful tool for carrying out - Hazard- vulnerability studies of urban areas and - Create awareness of the vulnerability of an area to natural hazard. Present study demonstrates the capability of the ArcGIS tools to carry out vulnerability assessment considering various options. The results are generated in the form of color-coded maps depicting the grid wise vulnerability index. These maps can be combined with hazard potential maps to obtain Hazard- Vulnerability-Risk maps that can be used by the stakeholders, policy makers, planners and engineers to identify the areas with potentially heavy damage and to assess the extent of damage so that the disaster management plans for the city can be strengthened.

11 Discussion/ Q&A

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