Hydro(geo)logical and geochemical approach to investigate the impact of active layer groundwater on runoff in the Austrelovenbreen watershed (Western Spitsbergen - 79°N)

• Main Authors: Quenet, M., Marlin, Christelle, Griselin, Madeleine, Noret, A., Monvoisin, G., Le Gal La Salle, C., Verdoux, P., Friedt, J.M., Saintenoy, Albane, Tolle, Florian
• Other Authors: Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Théoriser et modéliser pour aménager (UMR 6049) (ThéMA), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Laboratoire de Géochimie Isotopique Environnementale (GIS) / Université de Nîmes (GIS), Université de Nîmes (UNIMES)-Centre National de la Recherche Scientifique (CNRS), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Ice; Ny Ålesund; Ny-Ålesund; permafrost; Spitsbergen
• Online Access: https://hal.science/hal-00817304; https://hal.science/hal-00817304/file/EGU2013-702-4.pdf

International audience The recent climate evolution has led to a strong reduction of the continental cryosphere in High Arctic environ-ments. The meltwater from both glacier and permafrost active layer has therefore notably increased. However, theimpact of the permafrost-active layer on the runoff has been little studied. The studied watershed is that of the Aus-treloven glacier (10 km2), close to Ny-Ålesund (Spitsbergen, 79◦N) in a continuous permafrost area. Since the endof the Little Ice Age, this glacier has displayed a surface reduction with an average rate of 18 m.a−1. During thesummer (June to September), the thawing of the active layer forms a temporary water-table above the permafrost,that may exchange water and solutes with the surface water. In order to investigate the river water/groundwaterexchanges, several monitoring have been undertaken since 2010: physicochemical characteristics of surface waterand groundwater, potentiometric level, soil temperature). Geophysical prospecting (GPR and electrical resistivity)are used to study the geometry of the system. Besides, a total of 151 water samples were taken from the supraper-mafrost water table, springs, ponds, subglacial river and main streams during the summers 2011 and 2012 in orderto study the exchanges and to discuss the origin of the different water end-members (geochemical and isotopicend-members signatures, water-rock interactions and solute acquisition processes).The hydrographs at the catchment outlet show a seasonal evolution closely linked to climatic factors. However, al-though the meltwater from snow and glacier ice strongly contributes to the outlet flows, it does not fully explain allthe hydrological events. Indeed, the discharge from subglacial river and suprapermafrost groundwater are shownto constitute a river base flow. The groundwater water-table reaches a thickness up to 1.50 m for an active layerthickness of 2.50 m at maximum. The contribution of water-table towards the rivers might be consequent as thisprocess proceeds all ...