Abstract

Field measurements of water and sediment discharge and floodplain topography, numerical simulations of hydrology, and Landsat data on sediment concentrations were combined to estimate rates of transport and the fate of water and sediment in a 200 km reach of the central Amazon River. Results from field data collected during the annual flood in July 1986 indicate that sediment was transported to the flood plain at rates ranging from 3 to 5 t ⋅ d-1 ⋅ m-1, with percentage deposition >80% yielding vertical rates of 0.8 to 1.6 cm/day. Comparable rates were calculated from geographic information system overlays of numerically simulated specific water discharge and Land-sat-derived sediment concentrations. Rates for July 31, 1977, include 4 to 18 t ⋅ d-1⋅ m-1 of transport onto the flood plain and an average of 64% deposition at vertical rates from 0.4 to 3.3 cm/d. A 1 m higher flow on August 2, 1989, yielded, on average, higher rates of transport onto the flood plain, 8 to 15 t ⋅ d-1 ⋅ m-1, but lower percentage (46%)deposition, implying vertical rates between 0.3 and 2.9 cm/d.

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