Experimental analysis on sediment transport phenomena in channels equipped with inclined side weirs

Side weirs are particular structures used in hydraulic engineering for flow control in rivers and channels. In movable bed situations, the lateral discharge withdrawal can influence sediment transport processes causing an unexpected functioning of the weir; due to the possible changes in bed morphology, sediments from the main channel can be diverted in the evacuation channel as well. This paper summarizes the results of experimental analyses carried out to study these interactions for inclined weirs, under different hydraulic and geometric conditions. The results show the influence of weir’s length and inclination of the crest on the pattern of deposition and erosion zones in the main channel. The analysis of the experimental observations also confirm the validity of the De Marchi’s approach for modelling the behavior of inclined side weirs on movable beds. In addition, the predictive capability of a numerical method for estimating the diverted solid discharge from side weirs is tested. The comparison of observed and predicted sediment discharges outflowing from the lateral structure indicates the reliability of the tested method also for inclined side weirs.