Quantitative evaluation on the influence from cryosphere meltwater on runoff in an inland river basin of China

• Water cycle has accelerated.
• Meltwater accounted for 49% of the source runoff.
• Meltwater contributed by 21% to the outlet runoff.
• Water in cryosphere belt dominated runoff.

Under climate warming, increasing attention is being directed towards high altitude regions where glaciers are shrinking and frozen soil is in degrading. This study, taken Taolai river in Qilian Mountains as an example, is to quantify the relative contributions of cryosphere meltwater to outlet river, based on 221 water samples from precipitation, river, groundwater and meltwater during 2013–2014. The results indicated that cryosphere meltwater accounted for 49% of the total runoff in the source region, and this contribution rate decreased to 21% at the outlet of basin. In addition, precipitation and meltwater from cryosphere belt has contributed up to 78% of the outlet river runoff. An inverse altitude effect of stable isotopes for river water and groundwater is likely to occur, which is caused by the relatively larger contribution rate of frozen soil meltwater in the source region. The results could provide a comprehensive overview on the influence from cryosphere meltwater to hydrologic process in cold basins.