Evaporation, infiltration and storage of soil water in different vegetation zones in Qilian mountains: From an perspective of stable isotopes

Abstract. In arid areas, almost all the water resources in the basin come from mountainous areas. Nvertheless, the process of water storage and runoff generation has not been fully understood in different vegetation zones in mountainous areas, which is the main obstacle blocking human cognition of hydrological processes and water resources assessment. In current study, the spatiotemporal dynamics of stable isotopes were monitored in different water bodies and soil water storage in different vegetation zones in the upper reaches of Xiying River. The results show that: (1) The water storage capacity of surface soil was weak in vegetation zones, and soil water was mainly saved up in the middle and lower soil layers. (2) Surface and subsurface runoff could form in the Alpine Meadow and Coniferous Forest during the rainy season and the snow melting season. The lower elevation vegetation zones of Mountain Grassland and Deciduous forest evaporate strongly and infiltrate partially into the middle and bottom layers of the soil to store or recharge groundwater, rarely generating surface runoff. This work would provide a scientific foundation for reasonably explaining the mechanism of water production in mountainous areas of arid regions, and provide a reference for formulating management policies suitable for sustainable development of water resources and improving the ability to cope with climate change in arid areas.