title: A method for the assessment of long-term changes in carbon stock by construction of a hydropower reservoir.
abstract: Sustainability of hydropower reservoirs has been questioned since the detection of their greenhouse gas (GHG) emissions which are mainly composed of carbon dioxide and methane. A method to assess the impact on the carbon cycle caused by the transition from a natural river system into a reservoir is presented and discussed. The method evaluates the long term changes in carbon stock instead of the current approach of monitoring and integrating continuous short term fluxes. A case study was conducted in a subtropical reservoir in Brazil, showing that the carbon content within the reservoir exceeds that of the previous landuse. The average carbon sequestration over 43 years since damming was 895 mg C m[Formula: see text] and found to be mainly due to storage of carbon in sediments. These results demonstrate that reservoirs have two opposite effects on the balance of GHGs. By storing organic C in sediments, reservoirs are an important carbon sink. On the other hand, reservoirs increase the flux of methane into the atmosphere. If the sediments of reservoirs could be used for long term C storage, reservoirs might have a positive effect on the balance of GHGs.
authors.affiliation: Dpto. de Hidraulica e Saneamento (DHS), Univ. Federal do Paraná (UFPR), Setor de Tecnologia, Bloco 5, Caixa Postal 19011, Curitiba, PR, 81531-990, Brazil. juliowernery@gmail.com.
authors.forename: Julio Werner Yoshioka
authors.identifier: http://orcid.org/0000-0002-1877-1052
authors.initials: JWY
authors.lastname: Bernardo
authors.affiliation: Dpto. de Engenharia Ambiental (DEA), Univ. Federal do Paraná (UFPR), Setor de Tecnologia, Bloco 3, Caixa Postal 19011, Curitiba, PR, 81531-990, Brazil.
authors.forename: Michael
authors.initials: M
authors.lastname: Mannich
authors.affiliation: Institute for Water and River Basin Management, Karlsruhe Institute of Technology, Gotthard-Franz-Str. 3, Bld. 50.31, 76131, Karlsruhe, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Hilgert
authors.affiliation: Dpto. de Hidraulica e Saneamento (DHS), Univ. Federal do Paraná (UFPR), Setor de Tecnologia, Bloco 5, Caixa Postal 19011, Curitiba, PR, 81531-990, Brazil.
authors.forename: Cristovão Vicente Scapulatempo
authors.initials: CVS
authors.lastname: Fernandes
authors.affiliation: Dpto. de Engenharia Ambiental (DEA), Univ. Federal do Paraná (UFPR), Setor de Tecnologia, Bloco 3, Caixa Postal 19011, Curitiba, PR, 81531-990, Brazil.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bleninger
mesh_terms: D001938:Brazil; D002244:Carbon; D002245:Carbon Dioxide; D004784:Environmental Monitoring; D017752:Greenhouse Effect; D008697:Methane; D011210:Power Plants; D045483:Rivers
chemical_list: D002245:Carbon Dioxide; D002244:Carbon; D008697:Methane
keywords: Carbon cycle; Fluxes; Sedimentation; Sequestration