Evaluation of flow conditions in strongly curved open-channels is of vital importance in studying a variety of water engineering problems such as sedimentation, erosion, and contaminant transport. This work presents the impact of middle vanes on the water depth changes (super-elevation) in sharp bends. The behavior of these vanes while extending the up- and downstream channels is also investigated. Various experiments are conducted to verify the laboratory model, guarantee homogeneity of the data, and minimize the systematic errors. Accordingly, the water depth values are measured for three 30◦, 60◦, and 90◦ bends with various inlet discharges for gauging sections throughout and after the bend. It is found that, unlike mild bends, super-elevation in sharp bends is nonlinear. Moreover, the vanes shift the location of the maximum and minimum depths from the bisector toward the end of the bends. Vanes are able to decrease the super-elevation while their efficiency can be improved up to 90% by extending them into the up- and downstream channels. A new equation is also proposed to determine the maximum water depth gradients.
