River bend sediment management using modified triangular vanes

ABSTRACT Triangular vanes (TVs) are among the flow pattern correction structures which have recently been considered environmentally friendly structures against river bend bank erosion. However, the scour around the structure’s tip may cause its failure. On the other hand, it has been shown that the use of slot in the bridge pier and bridge abutment is effective in reducing scour depth, hence in this study, the effect of four different positions of rectangular slot on TV: Case 1) near the TV’s tip, parallel to the vane’s chord and close to the bed; Case 2) near the outer bank, parallel to the vane’s chord and close to the water surface; Case 3) horizontally and near the bed and Case 4) vertically and near the outer bank is experimentally studied in a 90° mild bend flume. The maximum scour depth (ds), and the point bar height at the end of experiments were compared with the case of no slot (Case 0). The best performance in reducing ds was obtained for Case 1 and then Case 3 with 24% and 19% reduction compared to Case 0, respectively. Poor performance was found for Case 2.