The changing magnitude and timing of riverine floods in India

Riverine floods are one of the most frequent and destructive types of natural hazards globally. Although India has densely populated floodplains, national-scale trends in flood discharge observations remain largely unknown. Using representative streamflow records, we assessed changes in flood magnitude and timing across India with the modified Mann–Kendall test and Theil-Sen’s Slope Estimator. Results show a decreasing trend in flood magnitude at 74% of gauging stations, and regional variations in flood timing. We further examined links between continental-scale climate signals and flooding by analyzing precipitation and soil moisture patterns in identified hotspots. Declining precipitation and soil moisture reduced monsoon flood magnitude by 17% per decade in the West and Central Ganga basin, while rising pre-monsoon rainfall increased flood magnitude by 8% per decade on the Malabar coast. Early precipitation in the lower Yamuna and delayed precipitation in the Upper Ganga advanced and postponed floods, respectively. Flood discharges were dampened in arid basins, and large catchments experienced reduced flood magnitudes. These insights enhance our scientific understanding of flood dynamics and support targeted policy and disaster management strategies across India.