Quantitative evaluation of the rainfall influence on streamflow in an inland mountainous river basin within Central Asia

摘要

Stable isotopes of water have been widely used in understanding the hydrological functions of alpine inland catchments. This study identifies dominant runoff generation mechanisms based on isotopic data (O-18 and H-2) of 487 rainwater and river-water samples from three tributaries in the Tarim River Basin in China for the period May-September 2013. The isotope hydrograph separation results provide a comprehensive overview of the rainfall influence on hydrological processes. Stream water and groundwater have varied responses to different intensities of rainfall events. Only a small proportion of rainfall is directly transported to the stream during such events. An inconsistent temporal trend of event water contribution is observed in the three catchments. The average fractional contributions of rainfall for the Tizinafu, Kumalak and Huangshuigou rivers are 10.3% (+/- 1.1%), 9.7% (+/- 2.9%) and 8.7% (+/- 2.4%), respectively.