The Madeira River is the second largest Amazon tributary, contributing up to 50% of the Amazon River's sediment load. The Madeira has significant hydropower potential, which has started to be used by the Madeira Hydroelectric Complex (MHC), with two large dams along the middle stretch of the river. In this study, fine suspended sediment concentration (FSC) data were assessed downstream of the MHC at the Porto Velho gauging station and at the outlet of each tributary (Beni and Mamoré Rivers, upstream from the MHC), from 2003 to 2017. When comparing the pre-MHC (2003-2008) and post-MHC (2015-2017) periods, a 36% decrease in FSC was observed in the Beni River during the peak months of sediment load (December-March). At Porto Velho, a reduction of 30% was found, which responds to the Upper Madeira Basin and hydroelectric regulation. Concerning water discharge, no significant change occurred, indicating that a lower peak FSC cannot be explained by changes in the peak discharge months. However, lower FSCs are associated with a downward break in the overall time series registered at the outlet of the major sediment supplier-the Beni River-during 2010.
Bibliographical noteFunding Information:
We express our gratitude to the SENAMHI from Bolivia, ANA from Brazil, and SO-HYBAM from Institut de Recherche pour le Développement (IRD) for providing the hydrological and sediment data used in this study, and the Peruvian Geophysics Institute for the internship the first author received. We would also like to thank Pascal Fraizy and Philippe Vauchel from IRD in France, Antonio Manzi from INPE in Brazil, Waldo Lavado from SENAMHI in Peru, Albert Kettner from the University of Colorado in the USA, Ana Callau Poduje from Leibniz Universität Hannover in Germany, and two anonymous reviewers for their effort and support. The first author was supported by a Doctoral Scholarship from the Coordination for Improvement of Higher Education Personnel (CAPES) of the Brazilian Ministry of Education. J.C.E. was partially supported by the French AMANECER-MOPGA project funded by ANR and IRD (ref. ANR-18-MPGA-0008).
Funding: The first author was supported by a Doctoral Scholarship from the Coordination for Improvement of Higher Education Personnel (CAPES) of the Brazilian Ministry of Education. J.C.E. was partially supported by the French AMANECER-MOPGA project funded by ANR and IRD (ref. ANR-18-MPGA-0008).
© 2019 by the authors.
- Fine suspended sediment concentrations
- Hydroelectric dams
- Madeira River
- Water discharge