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A comparison of the suspended and dissolved matter dynamics of two large inter‐tropical rivers draining into the Atlantic Ocean: the Congo and the Orinoco
Author(s) -
Laraque Alain,
Castellanos Bartolo,
Steiger Johannes,
Lòpez José Luis,
Pandi Albert,
Rodriguez Militza,
Rosales Judith,
Adèle Georges,
Perez Jesus,
Lagane Christelle
Publication year - 2013
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.9776
Subject(s) - tropical atlantic , sediment , context (archaeology) , hydrology (agriculture) , total organic carbon , environmental science , oceanography , drainage basin , discharge , geology , geography , ecology , geomorphology , sea surface temperature , archaeology , biology , geotechnical engineering , cartography
This study compares the total suspended sediment (TSS), total dissolved solids (TDS), and dissolved organic carbon (DOC) dynamics of two major inter‐tropical rivers, the Congo in Central Africa and the Orinoco in South America, focusing on sampling undertaken during the period 2006–2010. Both rivers are characterized by similar mean annual discharges into the Atlantic Ocean, on its eastern and western margins, respectively. For both rivers, the results presented are placed in the context of the available longer‐term hydrological time series (Congo: 1903–2010; Orinoco: 1926–2010). The key features of the recent records of material flux for both rivers were established and compared with other published data from the 20th century. The available discharge time series show that the rivers are characterized by similar maximum monthly discharges (Congo: 75 500 m 3 s ‐1 ; Orinoco: 85 500 m 3 s ‐1 ) and similar inter‐annual variability (Congo: 1.69; Orinoco: 1.66). However, contrasts in low‐flow regime (minimum low flows: Congo: 23 000 m 3 s ‐1 ; Orinoco: 2300 m 3 s ‐1 ) and seasonal variability (Congo: 3.3; Orinoco: 37.2), as well as in material fluxes were identified. Specific suspended sediment yields for the Orinoco (89 t km ‐2 yr ‐1 ) were very significantly higher than those for the Congo (9.4 t km ‐2 yr ‐1 ). These differences are mainly explained by contrasts in the physiographic characteristics of the two river basins, such as their contrasting relief. The differences between the TSS fluxes calculated for the Orinoco in this study and those indicated by published data from the second half of the 20th century can be explained by the impact of the hydroelectric dams built in the foothills of the Andean Cordillera. Changes in the TSS fluxes of the Congo are mainly explained by the impact of climatic change on total runoff. Copyright © 2013 John Wiley & Sons, Ltd.