Hydrological mass balance of boreal watersheds in the Canadian Shield

• Published in: Journal of Hydrology
• Main Authors: Nadeau, Simon, Rosa, E., Cloutier, V., Paran, Frédéric, Hélie, J.F., Graillot, Didier
• Other Authors: Groundwater Research Group & Geotop, Université du Québec en Abitibi-Témiscamingue (UQAT), Institut de Recherche en Mines et Environnement (IRME), Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT), Geotop & Département des sciences de la Terre et de l’atmosphère, Université du Québec à Montréal = University of Québec in Montréal (UQAM), Institut de Recherche en Mines et en Environnement, Université du Québec en Abitibi-Témiscamingue, Université du Québec à Montréal
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Groundwater; River discharge; Stable isotope; Boreal Shield; Hydrological mass balances; [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; Canada; Hudson; taiga; Taiga shield; James Bay
• Online Access: https://hal-emse.ccsd.cnrs.fr/emse-04113820; https://doi.org/10.1016/j.jhydrol.2022.128236

International audience This study aims at evaluating the hydrological balance of large watersheds of the Canadian Shield in the James Bay area in Northwestern Quebec, Canada. The focus is set on six rivers of the Canadian Shield altogether draining more than 185,000 km 2 of the Boreal Shield, Taiga Shield and Hudson Plains ecozones of Canada. River discharge measurements, geochemical data (δ 2 H, δ 18 O and electrical conductivity [EC] of water), remote sensing, and GIS models are used jointly to calculate water balances. The approach allows for partitioning the influence of rainwater, snowmelt, surface runoff, evaporation, transpiration, and groundwater discharge to the hydrological balances of watersheds. On an annual basis, the results suggest that runoff from rainwater (30–61 % of total precipitation) and snowmelt (18–40 % of total precipitation) are the main contributions to river discharge, while the contribution of groundwater discharge to rivers represents < 12 % of the total precipitation. Over the study area, this contribution represents 2–5 km 3 of water. The stable isotope mass balances allow for estimating watershed-scale evaporation over inflow ratios ranging between 2 and 10 % and suggest that transpiration has an isotopic composition close to summer rainwater. The hydrological balances further suggest that the total pool of water stored in the active portion of watersheds represents 10–20 % of the total annual precipitation, while the exports of groundwater beyond the limits of surface watersheds are negligible. The seasonal trends in the hydrological balances of monitored watersheds were further documented to provide insights into the sensitivity of watersheds as they face climate change. The observations are used to propose recommendations for monitoring of rivers in the Canadian Shield and to identify future research needs.