Investigating the Effect of Coastal Triangular Boundaries on the Topography of the 180-Degree of the Jangiye Bend of the Karoon River using a Physical Model

Meandering river bend migration is a common phenomenon which destroys agricultural lands and civil infrastructures around the river. The main cause of such migration is due to developing a secondary flow within the bend in which a helicoidally circulation is developed and as a results the scour hole at the outer bank toe is created which causes collapse of the outer bank and its migration. Over the last decade many countermeasures against such scour have been developed. These measures modify the flow within the bend redistribute the local bed shear stress for the purpose of reducing the toe bank scour. Triangular vanes are one of such structures that help stabilize the outer bank by modifying the flow pattern in the river bend to prevent the scouring of the outer bank. Triangular vanes have been studied successfully by Bhuiyan et al. (2010) in a sinuosity river path and in a 90 degree flume bend by Bahrami-Yarahmadi and Shafai Bejestan (2016). Based on these studies this measure, if designed properly, not only can shift the scour from the outer bank toe to the middle of the river, it transport sediment to the downstream of the vane and deposited in between the vanes which create a new bank. The structure has been defined environment friendly since it create an environment suitable for aquatic animals. The aim of the present study is to investigate the application of triangular vanes in a 180 degrees of Jangiyeh bend in Karoon River south of Ahvaz and to determine the bets distance for installing the vanes.