Uncertainties in streamflow projections: a comprehensive examination of variabilities arising from climate and hydrological models in the Tahtali Dam Basin, Turkey

Abstract

This study examines the uncertainties associated with streamflow projections under different flow conditions and model quantities in a dam basin of Turkey. By integrating eleven General Circulation Models (GCMs), five hydrological models (HMs), and two Representative Concentration Pathways (RCPs), we assess combinatorial model chain subsets using the All Possible Experiments (APE) approach. Our findings reveal that hydrological models contribute predominantly to the uncertainty in low-flow projections, while their impact is negligible in high-flow and mean flow changes. The uncertainty distributions related to GCM and HM quantities show asymptotic trends, with median values converging towards long-term uncertainty contributions. However, the range of uncertainty contributions narrows as flow conditions intensify, with GCM and HM uncertainties gravitating towards upper and lower bounds, respectively. This research emphasizes the importance of considering flow conditions and model quantities in uncertainty assessment, providing valuable insights for policymakers and water resource managers in developing robust strategies for future climate scenarios.