Abstract ID: 283

CARBON DIOXIDE RELEASE BY TROPICAL HYDROELECTRIC IN AMAZON

Hydroelectric reservoirs have been shown to release significant quantities of CO2 to the atmosphere. While most studies have considered only emissions from reservoir surfaces, fluxes downstream of dams are also likely to be important. The objective of the present study was to estimate the total emission of CO2 from the Balbina hydroelectric system in the central Brazilian Amazon, including both upstream and downstream fluxes, and to investigate the factors that influence these fluxes. Diffusive and ebullitive emissions were estimated at regular intervals both above and below the dam. Diffusive emissions were estimated using static chambers. Bubble fluxes were estimated with submerged inverted funnels in the reservoir and from the difference between gas discharge at the entrance and the outflow of the hydroelectric turbines. An inundation model derived from a bathymetric map and daily stage readings was used for the spatial and temporal interpolation of reservoir emissions. Annual emissions of CO2, upstream and down stream of Balbina dam were estimated at 2,450 and 104 Gg C, respectively, for a total annual flux of 2554 Gg C. Upstream emissions were predominantly diffusive with only 0.021 Gg C y-1 resulting from ebullition. On average, 39.7% of the downstream emission was released by ebullition at the turbine outflow. The remainder was lost by diffusion from the downstream river channel.

Session:  Public Policies and Sustainable Development - Sustainable management of natural resources and biodiversity in central Amazonian floodplains.

Presentation Type:  Oral