Human versus climate interactions on riverine flood characteristics in the largest Indian Peninsular basin

Abstract

Globally, over one in five people face 100-year flood risk, particularly in low-income regions. Flood risk is rising, especially in densely populated developing economies and areas with extreme meteorological conditions. Floods cause significant economic and health impacts, highlighting the urgent need for flood-resistant communities and preparedness. Policymakers must understand the regional and temporal distributions of flood risk to develop effective prevention and mitigation strategies. Human activities, such as dams and reservoir operations, have been shown to reduce flood intensity in many areas, though their impact varies by geography and purpose. This study investigates flood dynamics in the Godavari basin, the largest river basin in the Indian peninsula, significantly affected by large-scale dams and reservoirs. Using the Peaks Over Threshold (POT) method, generalized Pareto distribution (GPD), and CUSUM time series analysis, we analyzed flood characteristics such as peak, volume, and duration. Our results reveal that the east-central (Wainganga sub-basin) and eastern (Indravati and Sabari sub-basins) regions are major contributors to increased flood volume, peak, and duration in downstream areas. In contrast, the western and west-central Godavari regions, characterized by numerous dams, experience smaller flood volumes, peaks, and durations due to dam operations and moderate climatic conditions. However, undammed regions in the east-central and eastern Godavari, lacking flood control infrastructure and experiencing severe climatic conditions, face large-scale floods with high risk. These findings offer critical insights into regional flood characteristics and factors, supporting the development of effective flood management strategies for the Godavari basin.