Use este identificador para citar ou linkar para este item: https://repositorio.inpa.gov.br/handle/1/19312
Título: Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil
Autor: Dunne, Thomas
Mertes, Leal A.K.
Meade, Robert H.
Richey, Jeffrey E.
Forsberg, Bruce Rider
Palavras-chave: Banks (bodies Of Water)
Budget Control
Erosion
Floods
Floors
Sediment Transport
Sedimentation
Channelized Flow
Exchange Process
Overbank Flow
Physical Control
Sediment Budgets
Sediment Loads
Sediment Sampling
Tectonic Features
Rivers
Bank Erosion
Floodplain
Overbank Flow
River Channel
Sediment Budget
Sediment Transport
Sedimentation Rate
Trough
Amazon River
Floodplain
Fluvial Sediment
River Channel
Sediment Transport
Data do documento: 1998
Revista: Bulletin of the Geological Society of America
É parte de: Volume 110, Número 4, Pags. 450-467
Abstract: Sediment transport through the Brazilian sector of the Amazon River valley, a distance of 2010 km, involves exchanges between the channel and the flood plain that in each direction exceed the annual flux of sediment out of the river at Óbidos (∼1200 Mt yr-1). The exchanges occur through bank erosion, bar deposition, settling from diffuse overbank flow, and sedimentation in flood-plain channels. We estimated the magnitude of these exchanges for each of 10 reaches of the valley, and combined them with calculations of sediment transport into and out of the reaches based on sediment sampling and flow records to define a sediment budget for each reach. Residuals in the sediment budget of a reach include errors of estimation and erosion or deposition within the channel. The annual supply of sediment entering the channel from bank erosion was estimated to average 1570 Mt yr-1 (1.3 × the Óbidos flux) and the amount transferred from channel transport to the bars (380 Mt yr-1) and the flood plain (460 Mt yr-1 in channelized flow; 1230 Mt yr-1 in diffuse overbank flow) totaled 2070 Mt yr-1 (1.7 × the Óbidos flux). Thus, deposition on the bars and flood plain exceeded bank erosion by 500 Mt yr-1 over a 10-16 yr period. Sampling and calculation of sediment loads in the channel indicate a net accumulation in the valley floor of approximately 200 Mt yr-1 over 16 yr, crudely validating the process-based calculations of the sediment budget, which in turn illuminate the physical controls on each exchange process. Another 300-400 Mt yr-1 are deposited in a delta plain downstream of Óbidos. The components of the sediment budget reflect hydrologie characteristics of the valley floor and geomorphic characteristics of the channel and flood plain, which in turn are influenced by tectonic features of the Amazon structural trough.
DOI: 10.1130/0016-7606(1998)110<0450:EOSBTF>2.3.CO;2
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