Hydrological Connectivity in a Permafrost Tundra Landscape near Vorkuta, North-European Arctic Russia

Abstract

Hydrochemical and geophysical data collected during a hydrological survey in September 2017, reveal patterns of small-scale hydrological connectivity in a small water track catchment, north-European Arctic. Elevated tundra patches underlain by sands were disconnected from the stream and stored precipitation water from previous months. At the catchment surface and in the water track thalweg, some circular hollows, from 0.2 to 0.4 m in diameter, acted as evaporative basins with low d-excess values, from 2 to 4‰. Other hollows were connected to shallow subsurface runoff, yielding d-excess values between 12 and 14‰. ‘Connected’ hollows yielded a 50% higher dissolved organic carbon (DOC) content, 17.5±5.3 mg/L, than the ‘disconnected hollows, 11.8±1.7 mg/L. Permafrost distribution across the landscape is continuous, but highly variable. Open taliks exist under fens and small hummocky depressions, as revealed by electric resistivity tomography surveys. Isotopic evidence supports upward subpermafrost groundwater migration through open taliks under water tracks and fens/bogs/depressions, and its supply to streams via shallow sub-surface compartment. Temporal variability of isotopic composition and DOC in water track and a major river system, the Vorkuta R., evidence the widespread occurrence of the described processes in the large river basin. Water tracks effectively drain the tundra terrain and maintain xeric veg-etation over the elevated inter-track tundra patches.

Active Layer and Permafrost Investigations Using Geophysical and Geocryological Methods—A Case Study of the Khanovey Area, Near Vorkuta, in the NE European Russian Arctic

“…Regional climate has a Subarctic character: summer is short and cool, and winter is long and cold, lasting over 8 months from October to May. The total period without negative daily temperatures is only 70 days in average per year, and the mean annual daily temperature is −5.6 °C (Tananaev et al, 2021). Total annual snow accumulation is increasing.…”

“…Total annual snow accumulation is increasing. Precipitation is about 430 mm, of which from 50% to 70% fall as snow (Tananaev et al, 2021). In tundra landscape, snow accumulation increased by 1.8 cm yr −1 over the period 1998-2018 (Vasiliev et al, 2020).…”

“…The maximum annual ground temperature ranges between −0.5 °C and −1.0 °C at zero annual amplitude depth (around 12 m, Tananaev et al, 2021). A residual thaw layer is occurring annually between the base of the seasonally freezing layer at 2-3 m depth and the top of the permafrost layer at 4-5 m depth (Tananaev et al, 2021). Important cryogenic processes occur, including thermokarst and fluvial thermal erosion.…”

“…Important cryogenic processes occur, including thermokarst and fluvial thermal erosion. Frost boils are also common cryogenic features, mostly occurring in a narrow belt surrounding the water track valleys (Tananaev et al, 2021).…”

“…The target zone is the Khanovey railway station area, close to Vorkuta city, located on the west of the Ural Mountains (Figure 1). The study area, characterized by Quaternary sediments lying on Permian coal shale bedrock, exhibits a continuous permafrost layer (Tananaev et al, 2021). This region is crossed by the North Russian Railway, which represents the only land connection between Moscow city and the northern Arctic territories.…”