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 – 400058, India.

Also,

Research Scholar, Department of Civil Engineering,

Indian Institute of Technology (IIT) Bombay,

Powai, Mumbai – 400076, India.

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

Overview

• Mumbai City

• 437.71 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

Maharashtra Mumbai

Location Map of Mumbai city

Data and Technology used

Source: ArcGIS

Spatial Data – Download OSM Data Download

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)

𝐕𝐈𝐢 =(𝐕𝐢−𝐕𝐦𝐚𝐱)

(𝐕𝐦𝐚𝐱−𝐕𝐦𝐢𝐧)

- VIi is the vulnerability index for the indicator pertaining to the ith grid,

- Vi is the vulnerability value of the ith 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

Methodology

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

•

Length of the indicator in

each grid is calculated

using the clip and

intersect tools from the

ArcToolbox

Number of indicator in

each grid is counted using

the spatial join tool of

Overlay from the

ArcToolbox

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

Results

Vulnerability grid maps

Vulnerability index of each grid is scaled

from 0 to 1.

Railways Educational Buildings

Vulnerability

Level

Vulnerability

Index (VI)

Infrastructure density

No 0 No infrastructure

Low 0.25 Low infrastructure

Moderate 0.5 Moderate infrastructure

High 0.75 Dense infrastructure

network

Very High

or Critical

1 Very dense

infrastructure network

Vulnerability Classes based on VI

Results

Hazard x Exposure x Vulnerability = Disaster Risk

X X =

Hazard Exposure Vulnerability Risk

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.

Discussion/ Q&A

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