Hydrological characteristics of lakes in the eastern part of the Broknes Peninsula, Larsemann Hills, East Antarctica

Abstract

Broknes Peninsula (the area of the Progress station, Larsemann Hills, Princess Elisabeth Land, East Antarctica) is characterized by the presence of well developed hydrographic network consisting of reservoirs located not only in the bedrock, but also inside the glacier thickness and on its surface. As a rule, most of them are dammed by natural snowice weirs, which are often destroyed during the Antarctic summer. As a result of this process, glacial water outburst may occur. In the course of the summer season of the 63‑th Russian Antarctic Expedition (RAE) intensive hydrological field observations were carried out for identification and comprehensive investigation of potentially outburstprone reservoirs located in close proximity to Russian and foreign stations and field bases (area of the Progress station and the field base Law-Racovita). The works included: the organization of temporary pile and depth-stick water gauge stations, mapping positions of the shoreline of lakes (reservoirs), bathymetric surveys of them, as well as field hydro-chemical express analyses. Based on the results of the level measurement, it was found that most of the lakes of the oasis are characterized by a sharp drop in the height of the water surface level associated with the breakthroughs. In particular, the authors witnessed the breakthrough of the Discussion Lake, which occurred on January 22, 2018. This resulted in decrease of the water level by 0.95 m. Based on the data of the bathymetric surveys, the morphometric (hydrometric) characteristics of the lakes were calculated and detailed grids (regular net of rectangular matrices, in the nodes of which some effective values of the mapped values are located) were formed for the following numerical modeling of hypothetical and real breakthroughs of water bodies and construction of estimated hydrographs.

Retention time of lakes in the Larsemann Hills oasis, East Antarctica

“…In the Larsemann Hills oasis, the water outbursts were reported for Lake Progress/LH57 in years 2013 and 2014, and these outbursts resulted in the outflow of about 7.5-8.1 % of the total lake volume (Shevnina and Kourzeneva, 2017). The abrupt drop down of the water level/stage was also reported for Lake Nella/ Scandrett/LH72 in 2018 with releasing of the water outflow of 5.7 % of the lake total volume (Boronina et al, 2019). In this study, the water outburst due to the abrupt drop downs should be accounted for in the Eq.…”

“…For the land-locked lakes considered in out study, the annual volume changes do not exceed 1-2 % (Boronina et al 2019;Dvornikov and Evdokimov, 2017;Shevnina and Kourzeneva, 2017). Lake Stepped/LH68 provides water supply for the polar base Progress (Russia), thus the Eq.…”

“…Land locked lakes are free of ice in December-February, and their water temperatures reach 10.0-11.0 °C in January (Boronina et al, 2019;Gillieson et al, 1990). Lake Stepped is located in the old coastal lagoon, and connected to the sea through the underground leakage of water.…”

“…Their seasonal water cycle starts in December with the water accumulation due to melting of the seasonal snow/ice cover in the lake watersheds. In the first week of January, the volume of these lakes reaches maximum, and then rapidly decrease due to the water outburst into the sea (Boronina et al, 2019;Shevnina and Kourzeneva, 2017). It leads to the abrupt drop down of the water level/stage in these lakes.…”

Lake outbursts of the eastern part of the Larsemann Hills, East Antarctica, through snow and ice dams

“…During this period of time a significant increase in water level and a destruction of snow and ice dams, followed by the generation of outburst floods can be observed (Popov et al, 2017(Popov et al, , 2018Boronina et al, 2018Boronina et al, , 2019). Affecting severely the local infrastructure as well as transport and logistic operations, such phenomena are recognized as especially dangerous and, therefore, relevant to study.…”