Assessment and Mapping of Riverine Flood Susceptibility (RFS) in India through Coupled Multicriteria Decision Making Models and Geospatial Techniques
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Date
2023-11
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Abstract
Abstract: Progressive environmental and climatic changes have significantly increased hydrometeo rological threats all over the globe. Floods have gained global significance owing to their devastating
impact and their capacity to cause economic and human loss. Accurate flood forecasting and the
identification of high-risk areas are essential for preventing flood impacts and implementing strategic
measures to mitigate flood-related damages. In this study, an assessment of the susceptibility to
riverine flooding in India was conducted utilizing Multicriteria Decision making (MCDM) and an
extensive geospatial database was created through the integration of fourteen geomorphological,
meteorological, hydroclimatic, and anthropogenic factors. The coupled methodology incorporates a
Fuzzy Analytical Hierarchy Process (FAHP) model, which utilizes Triangular Fuzzy Numbers (TFN)
to determine the Importance Weights (IWs) of various parameters and their subclasses based on
the Saaty scale. Based on the determined IWs, this study identifies proximity to rivers, drainage
density, and mean annual rainfall as the key factors that contribute significantly to the occurrence of
riverine floods. Furthermore, as the Geographic Information System (GIS) was employed to create the
Riverine Flood Susceptibility (RFS) map of India by overlaying the weighted factors, it was found that
high, moderate, and low susceptibility zones across the country span of 15.33%, 26.30%, and 31.35%
of the total area of the country, respectively. The regions with the highest susceptibility to flooding
are primarily concentrated in the Brahmaputra, Ganga, and Indus River basins, which happen to
encompass a significant portion of the country’s agricultural land (334,492 km2
) potentially posing
a risk to India’s food security. Approximately 28.13% of built-up area in India falls in the highly
susceptible zones, including cities such as Bardhaman, Silchar, Kharagpur, Howrah, Kolkata, Patna,
Munger, Bareilly, Allahabad, Varanasi, Lucknow, and Muzaffarpur, which are particularly susceptible
to flooding. RFS is moderate in the Kutch-Saurashtra-Luni, Western Ghats, and Krishna basins. On
the other hand, areas on the outskirts of the Ganga, Indus, and Brahmaputra basins, as well as the
middle and outer portions of the peninsular basins, show a relatively low likelihood of riverine
flooding. The RFS map created in this research, with an 80.2% validation accuracy assessed through
AUROC analysis, will function as a valuable resource for Indian policymakers, urban planners, and
emergency management agencies. It will aid them in prioritizing and executing efficient strategies to
reduce flood risks effectively.