Physical modelling of artificial river replenishment techniques to restore morphological conditions downstream of dams

First applied in the 1980’s, the artificial replenishment of sediments is one technique proposed to solve the problem of sediment deficit downstream dams. The present experimental research aims at improving the technique of river replenishment and at providing an engineering answer and framework for its application. A systematic series of laboratory tests are run to understand the hydrodynamics of the river flow when the replenishment technique is applied. Erodible volumes, with different lengths (occupancy of the replenishment volume is 1/3 of the channel width) and submergence conditions (100% and 130% submergence of the replenished volume), reproducing sediment replenishments volumes, are placed along a channel bank. Different geometrical combinations (single volume, double aligned volumes, double aligned half-volumes, double alternated half-volumes) of erodible sediment volumes are tested. The influence of discharge, the distance travelled by the eroded sediments and the time evolution of the erosion process are presented and discussed.