Suspended sediment Yield in the Amazon basin. An assessment using the Brazilian national data set
Naziano
Filizola, ANA Brasil, naziano@ana.gov.br
(Presenting)
Jean Loup
Guyot, IRD Peru, jloup@amauta.rcp.net.pe
Frédérique
Seyler, IRD France, fseyler@lmtg.ups-tlse.fr
Gérard
Cochonneau, IRD France, gerard.cochonneau@mpl.ird.fr
Eurides
Oliveira, ANA Brasil, eurides@ana.gov.br
In this paper, we make use of a Brazilian National data set on suspended sediment data for the Amazon Region containing more than 2500 samples from 60 sites (Figure 1) which have been running since the 1970s and are still operated, on an almost quarterly basis. These data are useful for assessing suspended sediment yields in the biggest river basin on earth. We also consider the sampling procedures and the methods used for Total Suspended Sediment (TSS) discharge calculation in the Amazon Region using such data. An analysis of the contributions of the largest Amazon River tributaries to the total sediment load of the Amazon, and the relationship between TSS and water discharge was undertaken. The Brazilian data are very representative of the processes operating in the basin, particularly in the central flood plain and in the Brazilian and Guiana shields. A basic assessment of the data highlights the major Andean Suspended Sediment Yield contribution (more than 1000 10^6 t.km-2.yr-1) and the lower contribution from the shield areas (less than 100 10^6 t.km-1.yr-1). Due to the relatively effective spatial distribution of the TSS stations, it was possible to evaluate the shield contributions as represents 7% of the total Amazon River basin suspended sediment yield. A region marked by deposition was identified in the middle of the basin. A sedimentation rate for the “várzeas” in the Amazon River basin lowlands of between 3 to 6 mm.yr-1 is proposed. We also proposed a QS variation by month, at the mouth to the three most important rivers of the Amazon Basin, and a value for the Amazon River TSS discharge to the Atlantic Ocean of about 600 to 800 10^6 t.yr-1.
Submetido por Guyot Jean Loup em 18-MAR-2004
Tema Científico do LBA: SH (Hidrologia e Química das Águas)