Experiments to assess the efficacy of sediment flushing in reservoirs

© 2020 Taylor & Francis Group, LondonSediment flushing has been reported as an efficient measure for reservoir desiltation. Nevertheless, the efficacy of flushing varies substantially depending on factors such as topography, bed material, initial water head and outlets capacity. This study aims to analyze the influence of the initial water head on the flushing efficacy. This efficacy is defined as the ratio between the volume of sediments evacuated to that of water released. For that purpose, 30 laboratory experiments were conducted in a 12.5 m long and 0.30 m wide horizontal rectangular flume. There, 10 pairs hs ¿ hw were tested for 3 different reservoir volumes, where hs and hw stand for the initial sediment and water elevations respectively. The measurements consisted in videos from a side of the channel which allowed to characterize the evolution of the water and bed surfaces during the experiments. The results show that flushing efficacy increase as the ratio hw/hs decreases.