Role of groundwater in the hydrology of a glacial catchment in continuous permafrost conditions in Spitsbergen (Austre Lovénbreen, 79°N : hydrodynamic and geochemical approaches

• Main Author: Quenet, Mélanie
• Other Authors: Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université Paris Sud - Paris XI, Christelle Marlin
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2014
• Subjects: Spitsbergen; Arctic; Groundwater; Glacial hydrology; Water balance; Permafrost; Geochemistry; Hydrologie glaciaire; Géochimie; Spitsberg; Arctique; Pergélisol; Bilan hydrologique; Eaux souterraines; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Arctique*; permafrost; pergélisol
• Online Access: https://theses.hal.science/tel-01127168; https://theses.hal.science/tel-01127168/document; https://theses.hal.science/tel-01127168/file/2014PA112371.pdf

The hydrology, geochemistry and meteorology of a small, Arctic glacial watershed under continuous permafrost conditions (Austre Lovén glacier catchment area of 10 km2, western Spitsbergen, 79°N) were studied during the three hydrological years 2010, 2011 and 2012 to better define the role of suprapermafrost groundwater on both water and solute fluxes at basin outlet. The runoff period occurs on average over a 141 days period (σ = 4.5 days) between May 9-10 and October 26-27. The mean total discharge is 0.940 m a-1 (σ = 0.156 m a-1) divided into 79 % of meltwater (54 % of snowmelt and icemelt from the glacier, 18 % of snowmelt from the slopes and 7 % of snowmelt from the proglacial area), 18 % of effective summer precipitation and 3% of perennial subglacial discharge. Uncertainties in quantifying the runoff components and the total discharge itself don’t allow more precise quantification of water fluxes from the suprapermafrost groundwater by water balance. This study would so show that the suprapermafrost groundwater component would be negligible in the water balance and only constitute a transit tank for water. Indeed, the potentiometric level monitoring shows that the water-table thaws and freezes at similar depths despite recharge events occurring during summer. Those recharge events mainly occur in favor of important rain events (cumulative amounts on 2 to 8 days higher that 20 mm). The water-table discharges towards rivers. The monitoring of ground temperature indicates that the frozen ground (supposed permafrost) top is located at a maximum depth of 2.50 m for a groundwater thickness reaching up to 1.70 m, or 70 % of the active layer. Thermal data show ground temperatures between 0 and - 0.5°C, close to thaw temperature, which let suppose a permafrost degradation between 2.50 and 3.40 m deep is about to occur due to climate warming. Consequently, the suprapermafrost groundwater aquifer (active layer) is expected to thicken. Geochemical data show an increase of the basin surface water mineralization by ...