Author(s): Burkhard Rosier
Linked Author(s):
Keywords: Side overflow; Side weir; Water withdrawal; Aggradation; Bed morphology
Abstract: Side weirs are a widely used device to control flow processes along a channel or river course. The lateral loss of water is responsible for the reduction of sediment transport capacity in the main-channel yielding to aggradation and the formation of a local sediment deposit in the downstream weir alignment. The reduced cross section generates backwater effects and additional contraction and expansion losses. As a consequence, the head over the side weir rises and the side overflow discharge as well. The design discharge to be diverted over the weir is increased by this flow-sediment transport interaction in an uncontrolled way. Based on an experimental flume study, a semi-empirical model to predict the three-dimensional bed evolution of the aggraded channel reach in the vicinity of the weir is developed. The deposition shape is fairly well represented by an adapted Maxwell-type distribution function. The main input parameters are based on channel and weir geometry as well as flow and sediment transport variables.
Year: 2007