Modeling sediment pulses on an armored channel

Dams trap sediments in the upstream reservoir, thus the continuity in sediment transport along the river is interrupted. Several negative aspects related to the lack of sediment supply were observed downstream many dams and the artificial replenishment of sediment was applied as a method to restore natural morphological conditions. The replenishment technique may be seen as a pulse of sediments added to the channel. Once the pulse-like volume of sediments is added into the reach, it is seen like an alteration of the channel geometry producing cross section narrowing and flow acceleration lengthwise the river. The river geometry modification together with the water flow allow erosion and transportation of the replenished material. In this work, the response of the flow to the material added in the channel is studied by means of the 2D shallow water equations model in combination with the Exner equation for the sediment continuity equation. Computational outcomes are compared with experimental data obtained from several replenishment configurations studied in the laboratory. It is observed how the bed fining provokes a larger spread of the material without aggradation within the armored channel.