Experimental study the effect of hockey spur dikes angle on scouring and comparing to L-shape spur dike

Spur dikes are river training structures that developed from the natural river banks with proper length and angle from the flow dominant direction, cause to divert the flow attack at the riverside and the critical regions and directs the flow to the river central axis. There are several researchers focused on the effect of the spur dikes angles on the flow pattern however there is not any study on hockey spur dikes angle on scouring patterns. In present study, the effects of the hockey spur dikes angle on scouring and the bed topography was carried out experimentally while the results were compared to those provided for L-shape. The experiments were conducted on a series of hockey spur dikes also the L-shape in three various angles equal to ,  and  (towards the downstream channel lateral walls) inside a laboratory flume in 10.5m length, 0.5 width and 0.5m height under the clear water conditions. The results revealed the scour hole parameters including the length and thickness of the sediment hill are lower in hockey spur dikes than the L- shape by increasing the spur dikes angle. Furthermore, the maximum scour depth, mean area and volume of scouring are increased by 41.4, 41 and 75.5 percent in hockey and by 33.8, 39 and 73 percent in L-shape through increasing the angle from   to , respectively. Also, no scouring was taken place in the vicinity of the channel lateral walls downstream the hockey spur dikes, hence, those beter act against the destruction also in protection of river beaches against the erosion, with respect to the L-shape.