Shrinkage of the tarns in the High Tatras (Slovakia, Poland)

Abstract

This paper assesses the shrinkage of glacial lakes in the High Tatras by analysing the series of historical and actual orthophotomaps from 1949 to 2018. The shoreline dynamics during this period were established by detailed retrospective remote sensing, and the decrease in the former surface of the water was caused by intensive interaction between morphodynamic processes and the lake basins. Herein, we have identified 38 tarns with an assumed decline in the area. This assumption was based on a comparison of initial visual analysis of the historical aerial photographs and the current orthophotomaps which capture all High Tatras tarns. We selected ten tarns with the largest or most representative changes and performed detailed cartographic analysis on them. We also attempted this analysis over shorter periods whenever possible and herein we established from 2.5 to 32.2% decrease in lake water surface area during the monitored period. This decrease in shallow lake basins was accompanied by the presence of accumulated debris flows, fine fraction fluvial-proluvial deposits, and vegetation. The shallow glacial lake basins are sensitive indicators of irreversible changes in their catchment areas and this study, therefore, highlights the effectiveness of combining detailed orthophotomaps and historical aerial photos and GIS tools in researching glacial lakes shoreline dynamics in the alpine landscape. Retrospective shoreline analysis facilitates the assessment of the effects of morphodynamic processes on the development of tarns from the postglacial period until today.

The formation of fan‐deltas in mountain lakes: Findings from Zelené Kežmarské Lake (Slovakia)

“…The lake has lost 7.7% of its surface since 1949 AD (cf. Kapusta et al, 2021). A fan-delta with four distinct lobes was formed along the western shore of the lake (Figure 2).…”

“…Sands were washed out from the fan and delivered to the delta by high-energy flows conveyed by stream beds as well as over the fan surface (cf. Kapusta et al, 2021). density turbidity currents (cf.…”

“…The fines could also have been delivered from older morainic landforms (cf. Kapusta et al, 2021). Winsemann et al (2022) reported that erosion of meltwater and colluvial material, and resulting resedimentation can take place during the aggradation of a fan.…”

“…The main goal of our study was to identify processes forming fandeltas in mountain lakes based on geophysical surveys carried out in Zelené Kežmarské Lake (Slovakia). Previous studies on Zelené Kežmarské Lake aimed to determine sedimentation rates (Kotarba et al, 2002), and estimate the rate of the lake in-filling since 1949 (Kapusta et al, 2021). Acoustic surveys conducted by Dhavamani et al (2022Dhavamani et al ( , 2022a allowed for identification of the types and thickness of sediments filling the lake basin.…”

“…Moreover, the sedimentary structure of deltas provides the information about changes in lake shore lines in the past (e.g. Kapusta et al, 2018; Kapusta et al, 2021; Machlus et al, 2020; van Rensbergen et al, 1998).…”