Impacts of weir removal on channel dynamics in non-uniform sediment beds

Abstract

This paper presents an experimental study on the impacts of weir removal on the upstream channel dynamics in non-uniform sediment beds. It is found that weir removal promotes local scour and sandbar development in upstream channels, which are two dominant processes to be considered prior to any removal action. On the other hand, the mean sediment size and the geometric standard deviation of sediment mixtures are two governing and practical parameters in characterizing the sediment bed non-uniformity when local scour and bar development are concerned. Sand ribbons are observed in non-uniform beds due to sediment sorting and exert great influences on the bar system and the channel morphology.