Hydrological connectivity from glaciers to rivers in the Qinghai–Tibet Plateau: roles of suprapermafrost and subpermafrost groundwater

Rui Ma,Wenle Xing,Ziyong Sun,Shuo Wang,Mengyan Ge,Qixin Chang,Yalu Hu

doi:10.5194/hess-21-4803-2017

Rui Ma, Wenle Xing + Show 5 more

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https://doi.org/10.5194/hess-21-4803-2017

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Abstract

Abstract. The roles of groundwater flow in the hydrological cycle within the alpine area characterized by permafrost and/or seasonal frost are poorly known. This study explored the role of permafrost in controlling groundwater flow and the hydrological connections between glaciers in high mountains and rivers in the low piedmont plain with respect to hydraulic head, temperature, geochemical and isotopic data, at a representative catchment in the headwater region of the Heihe River, northeastern Qinghai–Tibet Plateau. The results show that the groundwater in the high mountains mainly occurred as suprapermafrost groundwater, while in the moraine and fluvioglacial deposits on the planation surfaces of higher hills, suprapermafrost, intrapermafrost and subpermafrost groundwater cooccurred. Glacier and snow meltwaters were transported from the high mountains to the plain through stream channels, slope surfaces, and supra- and subpermafrost aquifers. Groundwater in the Quaternary aquifer in the piedmont plain was recharged by the lateral inflow from permafrost areas and the stream infiltration and was discharged as baseflow to the stream in the north. Groundwater maintained streamflow over the cold season and significantly contributed to the streamflow during the warm season. Two mechanisms were proposed to contribute to the seasonal variation of aquifer water-conduction capacity: (1) surface drainage through the stream channel during the warm period and (2) subsurface drainage to an artesian aquifer confined by stream icing and seasonal frost during the cold season.

Highlights

Permafrost plays an important role in groundwater flow and hydrological cycles of cold regions (Walvoord et al, 2012)
We propose two mechanisms involved in the significant seasonal variation of the aquifer in waterconduction capacity, which were surface drainage through the stream channel and subsurface drainage to an artesian aquifer confined by stream icing and seasonal frost (Fig. 12)
By selecting a representative catchment in the headwater regions of the Heihe River in the Qinghai–Tibet Plateau as a study site, this research employed the groundwater head, temperature, geochemical and isotopic information to determine the roles of groundwater in permafrost and seasonal frost zones in hydrologically connecting the waters originating from glaciers in the high mountains to the lower elevation streams

Summary

Introduction

Permafrost plays an important role in groundwater flow and hydrological cycles of cold regions (Walvoord et al, 2012). This is especially true for the mountainous headwaters of large rivers. In these areas interactive processes between permafrost and groundwater influence water resource management, engineering construction, biogeochemical cycling, and downstream water supply and conservation (Cheng and Jin, 2013). Groundwater–surface water interactions in Alaska were more commonly found in areas of discontinuous permafrost where hydraulic connections were spatially and temporally variable (e.g., Anderson et al, 2013; Minsley et al, 2012; Walvoord et al, 2012).

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