Characteristics of water isotopes and hydrograph separation during the spring flood period in Yushugou River basin, Eastern Tianshans, China

Abstract

Many of the river basins in northwest China receive water from melting glaciers and snow in addition to groundwater. This region has experienced a significant change in glacier and snowpack volume over the past decade altering hydrology. Quantifying changes in water resources is vital for developing sustainable strategies in the region. During 2013, a water-isotope source apportionment study was conducted during the spring flood in the Yushugou River basin, northwestern China. The study found significant differences in water isotopes between river water, snowmelt water, and groundwater. During the study period, the isotopic composition of groundwater remained relatively stable. This stability suggests that the groundwater recharge rate has not been significantly impacted by recent hydro-climatic variability. The river water flow rate and water δ18O displayed an inverse relationship. This relationship is indicative of snowmelt water injection. The relative contribution of the two sources was estimated using a twocomponent isotope hydrograph separation. The contribution of snowmelt water and groundwater to Yushugou River were ~63% and ~37%, respectively. From the study, we conclude that snowmelt water is the dominant water source to the basin during the spring melt period