Climate change impact on water resources and management in Çoruh and Seyhan basins

Climate change is a process that adversely affects people globally in many aspects. Water resources are one of the most vulnerable since they depend on climatic conditions and are operated for various purposes (irrigation, hydropower, etc.). In this study, future snowmelt runoff and operation of the water resources together with hydropower production were performed based on climate change scenarios for the upstream of Coruh Basin and one of the main tributaries of Seyhan Basin in Türkiye. The CORDEX-Europe database was employed to generate an ensemble of five different Global Climate Models (GCMs) under the Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 scenarios. Climate data sets were adjusted for local bias corrections. Furthermore, evaluations were conducted with the Global Warming Levels (GWL) established within the scope of the Paris Climate Agreement. The HBV-Light model was used to predict future (2020-2099) reservoir inflows in mountainous snow-fed catchments. The results indicated a significant decrease in snow variables and inflows due to the projected increase in temperatures and changes in precipitation patterns. An ensemble of GCMs and GWL was used to estimate hydropower generation through reservoir operations with the monthly scenario-based Water Resources Assessment and Planning (WEAP) model. It is predicted that hydropower generation will decrease by 4-9% and 10-35% in the upstream of Çoruh and Seyhan Basins, respectively, over the last decades (2076-2099). In addition, four alternative management scenarios were also evaluated for revisiting the operational strategies of reservoirs that are exposed to climate change impacts and require measures to be taken against it.