The recent flooding (November 2005-2006) of Eastmain-1 (EM-1) reservoir is currently being monitored within a joint study (Hydro-Québec, Université du Québec à Montréal, McGill University, Environnement Illimité inc.). The main goal is to determine the GHG fluxes from various terrestrial and aquatic environments before and after flooding in order to establish the impacts, in terms of net GHG emissions, of creating reservoirs in northern environments. The results of GHG (CO₂, CH₄ and N₂O) fluxes and dissolved gases measurement campaigns carried out during the open-water period and under-ice in this newly created reservoir are presented, and compared to those obtained in the natural aquatic environments present before flooding. The CO₂ emissions were 8 to 10 times higher in the first year after flooding (2006) than those measured in the aquatic environments before flooding and decrease to about 3 times those of natural systems in the second year after flooding (2007). The CH₄ emissions increased by around 3 times the first year and returned to natural values in the second year after flooding. No changes were observed in the N₂O emissions before and after flooding.

GHG FLUXES (CO2, CH4, N2O) OF THE FIRST THREE YEARS AFTER FLOODING OF THE EASTMAIN-1 RESERVOIR (QUEBEC, CANADA)

GHG FLUXES (CO₂, CH₄, N₂O) OF THE FIRST THREE YEARS AFTER FLOODING OF THE EASTMAIN-1 RESERVOIR (QUEBEC, CANADA)