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Contribution from frozen soil meltwater to runoff in an in-land riverbasin under water scarcity by isotopic tracing in northwestern ChinaContribution from frozen soil meltwater to runoff in an in-land river basin under water scarcity by isotopic tracing in northwestern China Li Zongxing a,b, , Feng Qi a, Q.J.Wangb, Yong Song b, Cheng Aifang c, Li Jianguoa a Gansu Hydrology and Water Resources Engineering Research Center/Key Laboratory of Ecohydrology of In-land River Basin, Cold and Arid Region Environment and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China b CSIRO Land and Water, Private Bag 10, Clayton South, VIC 3169, Australia c Key Laboratory of Disaster Monitoring and Mechanism Simulating of Shaanxi Province, Baoji University of Arts and Sciences, Baoji 721013, Shaanxi, China a b s t r a c t Cryosphere meltwater has been recognized as an important source of local water resources. However, there are few assessments on the contribution from frozen soil meltwater. In this study, we quantify the fraction from frozen soil meltwater and glacier snowmeltwater to runoff in Shiyang River, an in-land river basin of northwestern China, where glaciers were disappearing and frozen soil was in degradation. A large number of samples for precipitation, surfacewater, groundwater, frozen soilmeltwater and glacier snowmeltwater have been collected and analyzed for their isotopic compositions. Results indicated that runoff was mainly generated from the cryosphere belt, and it was found that frozen soil meltwater was responsible for 20%, on average, of the outlet river water during flood season in the basin. The contribution rates from frozen soil meltwater to the outlet river runoff changed among the seven sub-basins. The results confirmed that frozen soil meltwater has played an important role in runoff of in-land river basins, and evaluating its influence on the hydrological process under a climate warming scenario is of great significance.
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