Suspended sediment yields in the Amazon basin: an assessment using the Brazilian national data set

Abstract

AbstractIn this paper, we make use of a Brazilian national data set comprising suspended sediment data for the Amazon region. This contains more than 2500 samples from 60 sites that have been running since the 1970s and are still operated on an almost quarterly basis. These data provide a valuable basis for assessing suspended sediment yields in the largest river basin on earth. We also discuss the sampling procedures and the methods for total suspended sediment (TSS) flux calculation employed in the Amazon region. An analysis of the contribution of the largest Amazon River tributaries to the total sediment load of the Amazon and the relationship between TSS and water discharge has been undertaken. The Brazilian data provide representative information on sediment transport within the basin, particularly for the central flood plain and in the Brazilian and Guiana shields. A basic assessment of the suspended sediment load data highlights the major Andean TSS contribution (more than 1000 106 t year−1) and the lower contribution from the shield areas (less than 100 106 t year−1). On the basis of the data from the network of TSS stations, the shield areas are estimated to contribute 7% of the TSS yield from the Amazon River basin. A region of deposition has been identified in the middle of the basin; and the sedimentation rate in the ‘várzeas’ in the Amazon River basin lowlands has been estimated to be between 3 and 6 mm year−1. Copyright © 2009 John Wiley & Sons, Ltd.