Simulating the hydrological responses to climate change of the Xiang River basin, China

The responses of stream flow, actual evaporation, and soil moisture to climate change in six catchments within Xiang River basin, China, are investigated using Variable Infiltration Capacity (VIC) model. Results show that stream flows are highly correlated to precipitation while weakly correlated to temperature, which indicates precipitation governs variability of stream flow for these catchments. The VIC model performs well at simulating monthly discharge, with Nash Sutcliffe Efficiencies (NSEs) exceeding 70 % and relative errors (REs) of the volumetric fit falling in the range of ±10 % for both calibration and validation periods. The model can simulate seasonal cycles of soil moisture and actual evaporation reasonably well. Due to humid climate of the region, stream flows are more sensitive to changes in precipitation than to change in temperature, while soil moisture and actual evaporation tend to be relatively more affected by temperature. A 2 °C rise in temperature will lead to 5.62 % (4.3–7.45 %) decrease in stream flow, 6.45 % (5.8–7.02 %) increase in actual evaporation, and 5 % (4.16–5.59 %) decrease in soil moisture. A 10 % increase in precipitation will result in 14.17 % (13.44–15.70 %), 5.22 % (4.32–5.62 %), and 4.57 % (2.90–4.96 %) increases in stream flow, actual evaporation, and soil moisture, respectively.