Open AccessCO 2 emissions from a tropical hydroelectric reservoir (Balbina, Brazil)
Author(s) -
Kemenes Alexandre,
Forsberg Bruce R.,
Melack John M.
Publication year - 2011
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010jg001465
Subject(s) - hydroelectricity , environmental science , outflow , hydrology (agriculture) , greenhouse gas , flux (metallurgy) , discharge , atmospheric sciences , drainage basin , geology , oceanography , geography , ecology , materials science , geotechnical engineering , cartography , metallurgy , biology
Hydroelectric reservoirs can release significant quantities of CO 2 , but very few results are available from the tropics. The objective of the present study was to estimate the emission of CO 2 from the Balbina hydroelectric reservoir in the central Brazilian Amazon. Diffusive and ebullitive emissions were estimated at regular intervals, both above and below the dam, using a combination of static chambers and submerged funnels. Gas releases immediately below the dam were calculated as the difference between gas flux 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 spatial and temporal interpolation of reservoir emissions. Annual emissions of CO 2 , upstream and downstream of Balbina dam for 2005, were estimated as 2450 and 81 Gg C, respectively, for a total annual flux of 2531 Gg C. Upstream emissions were predominantly diffusive with only 0.02 Gg C yr −1 resulting from ebullition. On average, 51% of the downstream emission was released by degassing at the turbine outflow, and the remainder was lost by diffusion from the downstream river. The total annual greenhouse gas emission from Balbina dam, including the CO 2 equivalent of previously estimated CH 4 emissions, was 3 Tg C yr −1 , equivalent to approximately 50% of the CO 2 emissions derived from the burning of fossil fuels in the Brazilian metropolis of São Paulo.