Flood Risk Assessment Due to Urbanisation and Climatic Factors using Geospatial Approach A Case Study of Ghaggar River Basin

Abstract

Flooding, among other natural disasters that can also be called anthropogenic, is the most frequent and devastating. Flooding over an area depends on rainfall and geomorphological, climatic, and social factors. From 1900 2021, approximately 5593 flood events occurred worldwide, out of which 66% occurred after 2000. In the Asian continent, 2324 flood events occurred during 1900-2021. In the Asian continent, 13.5% of the total Asian flood occurred in India, followed by China (13.3%), Indonesia (10.6%), Philippines (6.7%), Pakistan (4.6%), Afghanistan (4.2%), Bangladesh (4.1%) and other countries. The decadal economic losses in India found to be $0.1billion during 1960-1969, $1.6 billion during 1970-1979, $4.0 billion during 1980-1989, $9.5 billion during 1990-1999, $16.8 billion during 2000-2009, $41.2 billion during 2010-2019 and 13.6 billion during 2020-2021. Floods in India have majorly occurred in the well-known river basins of India such as Ganga, Brahmaputra, Yamuna, Mahanadi, Testa, Kosi, Cauveri, Narmada, Tapi, Krishna, etc. Studies of flood hazard and vulnerability has been conducted widely in large river basins or at the regional level. Less or no attention has been given to the small river basins. Ghaggar River Basin is one of the small basins located in northern India and sub-basins of the Indus River basin. Several flood events of different intensities have occurred in this river basin. However, the 1993 flood event was the most devasting flood in the basin. This study aims to determine the rainfall trend analysis and extreme rainfall events in the study area. This study focussed on analyzing flood zones in the Ghaggar River basin using rainfall trends and extreme rainfall as flood factors. The impact of change in land use land cover in urbanisation on flooding over an area has been analyzed, and future flood maps have been projected. The dataset used for this study was collected from different sources. Software such as ArcGIS, Terrset Idrisi, SPSS, R, and Climdex were used to analyze these datasets.