Flood vulnerability and slum concentration mapping in the Indian city of Kolkata: A post-Amphan analysis

ABSTRACT The landfall of super cyclone Amphan, which affected Southern West Bengal and Orissa in 2020 and devastated human life, exposed the failure of urban infrastructure. On May 20, 2020, the storm alone recorded a rainfall of 236 mm in 24 h in Kolkata, capital city of West Bengal, pushing the total rainfall of May to 359.1 mm while averaged value of precipitation in May (2010–2019) stands at 117.5 mm. So, it further calls for relooking at climate preparedness for the Indian cities. In 2015 also, severe floods had affected more than six million people across the country of India alone, with over 250,000 people evacuated. In this context, the urban flood risks and major contributing factors in the Indian city of Kolkata have been discussed in this paper. The recurrence of floods and the exploration of causes repeatedly point to a situation of increased precipitation due to climate change, worsened by unregulated urbanization. The vulnerability assessment and calculation of Flood Vulnerability Index (FVI) for Kolkata is also conducted. It reveals the differential degree of vulnerability of city dwellers depending on location and infrastructure. The study leads to form a data base to infer characteristics and determine priority settings for the vulnerable urban population living in slums located in poorly drained areas of the city. A basin-wise analysis in KMC area reveals major urbanization coupled with decaying drainage system in the vulnerable basins as the main reason for aggravated flooding situation.