CLIMATE CHANGE INDUCED HYDROLOGICAL SHIFTS IN ESTIMATION OF RAINFALL-RUNOFF PROCESS BASED ON HEC-HMS SIMULATION

Water resources are inherently influenced by factors such as weather patterns, topography, geological conditions, and environmental characteristics.These interrelated variables present significant challenges in accurately assessing future water availability, particularly under a changing climate.According to the Intergovernmental Panel on Climate Change (IPCC), the rise in greenhouse gas concentrations contributes to global sea level rise and increases the frequency and intensity of extreme weather events, including storms, heavy rainfall, and droughts.To assess the potential impacts of climate change on the hydrological cycleparticularly rainfall-various modeling approaches are employed.These include Global Climate Models (GCMs), Regional Climate Models (RCMs), and hydrological models, especially for local-scale studies covering areas around 200 km.This paper aims to identify the hydrological parameter shifts from Global Climate Model of Inter Pierre Simon Laplace Climate Model version 6 Low Resolution (IPSL-CM6A-LR) using 5 different future projections of SSP1-1.9,SSP2-4.5 , SSP3-4.6,SSP4.3.7 and SSP5-8.5 at an interval of 10 years past experimental data (2015-24) and near-century projection of 10 years (2025-34), 20 years mid-century projection of 2035-54 and end-century projection of 30 years from 2055-84.The HEC-HMS model results indicate significant variability in peak discharges under different climate scenarios.SSP4-6.0 consistently shows higher runoff, while others fluctuate, reflecting climate uncertainty.SSP3-7.0 projects a 67.3% increase in runoff, posing severe risks to flood dynamics and watershed stability.Overall, runoff may rise by 64.4% mid-century.The HEC-HMS model simulation results reveals that the variation of rainfall-runoff is uncertain between different Share Socio economic Pathway (SSP's) scenarios of past and future century projections due to climate change emission scenarios in the Erravagu watershed in Telangana state of India.