India's flood risk assessment and mapping with multi-criteria decision analysis and GIS integration

India's diverse geography poses significant flood risks, addressed in this study through the geographic information system and multi-criteria decision analysis. This comprehensive flood risk assessment considers seven parameters: mean annual precipitation, elevation, slope, drainage density (DD), land use and land cover, proximity to roads, and distance to rivers. The findings indicate that flood vulnerability is primarily influenced by rainfall, elevation, and slope, with DD, land use, and proximity to roads and rivers also playing crucial roles. Experts weighed these factors to create a thorough flood risk map using the normalized rank index and normalized weight index, categorizing areas into five risk levels: very high, high, moderate, low, and very low. The study reveals that 3.40% of the area is at very high risk, 32.65% at high risk, 39.72% at moderate risk, 20.97% at low risk, and 3.25% at very low risk. These results highlight how human and natural factors interact to influence flood risk, with vulnerable areas characterized by low elevations, steep slopes, high drainage densities, and proximity to rivers or roads. The findings provide valuable insights for policymakers, scientists, and local authorities to develop strategies to mitigate flood losses across India's varied landscapes.