Assessment of Climate Change Impacts on the Hydrological Behavior of the Sarbaz River Basin Using CMIP6 Climate Models

Document Type : Original Article

Author

Civil Engineering and Water Resources ManagemenT

10.22044/jhwe.2025.16321.1068

Abstract

This study introduces a framework for assessing climate change and flow conditions by integrating the latest climate simulations from the CMIP6 project (HadGEM3-GC31-LL model) with the Soil and Water Assessment Tool (SWAT), while also evaluating the influence of different climate model resolutions. A total of 66 hydrological and environmental flow indicators from the Indicators of Hydrologic Alteration (IHA) were calculated to assess future extreme flows in the Sarbaz River Basin, located in Sistan Province, which is particularly vulnerable to flooding. Results indicate that by the 2030–2050 period, compared to the baseline period of 1990–2019, annual precipitation, streamflow, and maximum and minimum temperatures are projected to increase by 6.9%, 9.9%, 0.8°C, and 0.9°C, respectively. Monthly precipitation and streamflow are expected to rise especially during the monsoon season (June–September) and early wet periods (December). The magnitude of minimum 1-, 3-, 7-, 30-, and 90-day flows is projected to increase by 7.2% to 8.2%, while peak flows could rise by 10.4% to 28.4%. Finally, significant differences were observed between high- and low-resolution climate models, with high-resolution models predicting an 11.8% increase in average monthly flows during November–January, compared to just 3.2% in low-resolution models.

Keywords