Optimizing the Desilting Efficiency of Submerged Vane Fields at Lateral Diversions

The design criteria of submerged vane fields used to control the transfer of sediments into lateral channel diversions have been mostly based on suggestions of some fundamental studies on vane fields aiming to protect riverbanks against erosion. Indeed, although there are studies that investigate the effect of some characteristic parameters of submerged vanes on the desilting of lateral diversions (prevention or reduction of lateral sediment ingestion), they do not adequately cover all pertinent parameters and their significant ranges. In view of the gap of knowledge resulting from this incomplete parametric coverage, an investigation comprising 26 experiments was conducted. It investigated the effects of geometrical vane parameters and specific water discharge ratios on the desilting efficiency of submerged vane fields and on the bed morphology around a 90° lateral water diversion. The vanes displayed skew angles between 10° and 50°, and their heights were 0.2 to 0.4 times the approach flow depth. The distance from the channel bank to the inner vane row and the streamwise distance between vane arrays were, respectively, 0.7 to 1.5 and 2.0 to 3.0 times the approach flow depth. The specific water discharge ratio, $q_R$, varied between 0.1 and 0.3, and the number of vane rows was 6 and 3. The skew angle and the specific water discharge ratio were the most effective parameters on desilting, whereas the others had a small effect within the experimental limits of this study. The optimal desilting efficiency, $\approx 94\%$, was achieved when the skew angle was equal to 45° and $q_R$ was kept in the range of 0.1 to 0.2.