Scientists identify evaporation fractionation and streamflow components of Kaidu River Basin

A group of scientists from Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences recently carried out a stable isotope-based research on the Kaidu River Basin, and identified the evaporation fractionation and streamflow components of the mountain-oasis system.

Results of their study were published on recent issue of Hydrological Processes.

Based on stable water isotopes in stream water, groundwater, winter surface snow, and glacier meltwater, the research found clear seasonal variations in stream water in this region. The evaporation enrichment of δ18O was higher in summer and autumn and lower in spring.

Results indicated that glacier meltwater and groundwater, rather than recent precipitation, were the predominant recharge sources for river run-off of the Kaidu River. However, the contribution depends highly on the temperature affect in this area.

Groundwater was identified as the predominant contributor in the oasis region to Kaidu River. While in the mountains, groundwater was the dominant in spring and autumn, and meltwater of glaciers became the main contributor in summer.

Located on the southern slope of the Tienshan Mountains, the Kaidu River Basin not only provides the major recharge source for the Bosten Lake but also is one of four origins of the Tarim River, China's largest inland river.

“Studying the evaporation loss of stable water isotopes and the contribution of each streamflow component to river run-off in the Kaidu River Basin is crucial for understanding the mechanisms of the water cycle in the Tienshans region,” said CHEN Yaning, scientist from XIEG who lead the study.