Flood Vulnerability Assessment using Geospatial Techniques: Chennai, India

Timely and accurate damage assessment due to floods is crucial for the authorities to respond. Damage assessment and vulnerability mapping of Chennai flooding 2015 is presented. Objectives: The key objective of the paper is to quantify the extent of inundation, the damage incurred to the built environment, road and railway networks by mapping the flood vulnerable areas based on watershed analysis. Methods/Analysis: Landsat-8 OLI, Sentinel-1 and CartoDEM-3 R1 data of the study area during the flooded period were analyzed using geospatial techniques such as Normalized Difference Water Index, Normalized Difference Vegetation Index, Normalized Difference Built-up Index, Iso-Cluster Unsupervised Classification and Spatial Analyst tool. Findings: The results showed that 18% of the Chennai Metropolitan Area (CMA) (including 56 sq.km of the built fabric, 3742 km road length) was inundated directly affecting 21% of the total population. Novelty/Improvement: Based on the results, the study area is classified into low, medium and high vulnerable areas. Suitable directions for effective disaster management are recommended.