GNGTS 2018 - 37° Convegno Nazionale

686 GNGTS 2018 S essione 3.2 ERT AND GPR WATERBORNE SURVEYS ON A HIGH-ELEVATION ALPINE POND (NW ITALY) L. Sambuelli 1 , C. Comina 2 , C. Colombero 1 , V.J. Rumbos Ruedas 1 , C. De Regibus 1 , N. Colombo 3 , M. Freppaz 3 1 DIATI, Politecnico di Torino, Italy 2 DST, Università di Torino, Italy 3 DISAFA, Università di Torino, Italy Introduction. High-elevation lakes are a common feature of mountain environments and play an important role in the hydrological and chemical dynamics of mountain watersheds (e.g., Catalan et al. , 2006; Salerno et al. , 2014). These lakes are also recognised as key reference freshwater sites for global scale processes, due to the lack of direct human influence and because their physical, chemical, and biological properties respond rapidly to climate changes (e.g., Carpenter et al. , 2007; Lami et al. , 2010). Usually, water bodies located in high mountain environments are characterised by small dimensions, and can be defined as ponds (Hamerlík et al. , 2014). Their relatively low water volumes and high surface area to depth ratios make these features more fragile (Buraschi et al. , 2005). Moreover, high-elevation lakes and ponds are often located in basins characterised by the permafrost presence; the degradation of permafrost has been reported to deeply impact the surface water quality (Colombo et al. , 2018a). Thus, high-elevation ponds should be considered as key “field” laboratories for the study of climate change impacts on aquatic ecosystems. In this context, waterborne geophysical methods can map hydrogeological information, correlating geophysical parameters to hydrological and geological properties (Colombero et al. , 2014; Colombo et al. , 2018b), and deriving fundamental information for further investigations such as hydrochemical analyses (Colombo et al. , 2018c). In this work, we present the results of waterborne ground penetrating radar (GPR) and electrical resistivity tomography (ERT) on the Bowditch Pond, a high-elevation pond located in NW Italian Alps. Fig. 1 - Location of the study area in Italy and overview of the investigated pond basin (Digital orthoimage year 2006, source: Ministero dell’Ambiente e della Tutela del Territorio e del Mare - Geoportale Nazionale, http://www.pcn. minambiente.it/GN) . The black dashed line indicates the basin border.