A study on the dynamics of an Alpine Lake: the Seracchi Lake case

In the context of the ongoing climate change, there is an increasing urgency and interest in characterizing the mountain environment and gaining a deeper understanding of its dynamics. This is particularly important in the Alps, where the increase in average air temperature has doubled the average global temperature increase. To address this pressing issue, the CC-Glacier Lab was established at the Politecnico di Torino in 2021, with a focus on studying and characterizing the Rutor Glacier and its proglacial area in the Aosta Valley region, Italy. This thesis was conducted under the supervision of the hydrological team working with the CC-Glacier Lab, with the aim of improving knowledge about the largest proglacial lake in the area, known as Seracchi Lake (Lago dei Seracchi). By means of geomatic, geophysical, and hydrological data collected over two years (2021 and 2022), this thesis provides valuable insights into the morphology and hydrology of the lake. The research includes the reconstruction of the lake's bathymetry, the elaboration of surface area-water level and volume-water level curves, and the determination of the water budget. In particular, the accurate reconstruction of the inflow time series, which was challenging to measure directly due to the rugged nature of the area, is a significant achievement of this study. These findings have proven useful to obtain a deeper understanding of the link between hydrological dynamics and temperature as well as hydrological dynamics and precipitation conditions. The correlation between maximum and mean inflows with temperature is investigated, and the days with precipitation events are studied separately from the days without precipitation. Three parameters are calculated to characterize the lake dynamics: the difference between the maximum inflow and the maximum outflow value, the time delay between the two values, and the retention volume. A comparative analysis between the reference summer of 2021 and the notably dry summer of 2022 reveals that, on average, the retention volume was 82\% higher than in 2021, and also the difference between the maximum inflow and outflow was 32\% higher, while the time delay remained approximately the same. Moreover, the general increase in $Q_I_N$ values which was recorded was probably related to an increase in glacier ablation. This might show the lake's potential as a proxy for glacier retreat. In conclusion, this thesis represents an important first step in characterizing the studied area comprehensively. The methodology, results, and conclusions presented in this study contribute significantly to the understanding of the hydrological dynamics of Seracchi Lake and its implications in the context of climate change and glacier retreat. However, further investigations should be carried out without neglecting the importance of continuous monitoring and assessment of this alpine ecosystem.