The patterns of erosion and sedimentation with bendway weirs at a 90 ° bend

Bendway weirs are short-height structures that are completely submerged and are constructed to control the movement of bends, improve shipping conditions, create aquatic habitats, etc. The purpose of this study was to evaluate the pattern of erosion and sedimentation in a 90 degree bend with a relative radius of curvature 3.3 in the presence of Bendway weirs. To achieve this goal, a series of weirs with relative height 30 and 70% and crest slope of 0 and 7% were constructed on the outer wall of the bend. The angle (〖60〗^°), length (30% of channel width) and distance between weirs (3 times of weir length) were considered constant. The results show that due to the construction of weirs with relative height of 70% and flat crest slope, the maximum sedimentation (56.66% higher than the no-structure state) occurred at the maximum scour location. The maximum relative depth of scour in weirs with a relative height of 70% was about 17% higher than its value in weirs with a relative height of 30%. By increasing the crest slope for weirs with a relative height of 30%, the average maximum relative scour depth decreased by almost 27% in all hydraulic conditions around weir 5.