Impact of Climate Change and Land Use Land Cover Dynamics on Catchment Hydrology in a Sub-Basin of the Upper Krishna River, India. Final Paper Number: H23A-0982 Tuesday, 10 December 2024; 13:40 -17:30 EST

The changing climate and land cover dynamics pose significant challenges in estimating water-related scenarios and influence the decision-making processes. Therefore, assessing the changes occurring in large river basins that cater to the demands of a large demography is crucial. This study focuses on a sub-basin in the Upper Krishna River, part of the Krishna River-the fifth largest basin in India. Major cities such as Kolhapur, Sangli, and Vijaypura are situated along the Krishna River, and it also features a multipurpose reservoir serving as the outlet point of the study area. Over the past three decades, the basin has experienced various flood events, with the most catastrophic occurring in 2019. The basin covers a total geographical area of 19,068 square kilometres, predominantly comprising agricultural land, which accounts for approximately 70% of the area. The future land use scenarios of the study area were generated for the mid-century (2049) using ANN and CA Markov approach. The ensemble of five Regional Circulation Models (RCM) from Coupled Model Intercomparison Projects (CMIP6) was used for future climate projection under shared socioeconomic pathways SSP 4.5 and SSP 8.5. The projected climate data was used with the SWAT model, and the model performance was evaluated based on R2, ENS, and PBIAS values, indicating very good agreement between observed and simulated discharge. It was found that surface runoff has increased by about 32% and 39%, and water yield has increased by about 21% and 28%. Similarly, sediment yield has also increased by around 26% and 34%. This research underscores the need for proactive assessment and management strategies to address the evolving climatic and land cover changes impacting large river basins.