Numerical Investigation of the Effect of a Pair of Protective Spur Dikes on the Scouring around the Series Spur Dikes

Among the approaches to reduce flood damage is to reduce the flow rate near the shore by spur dikes. The study first simulated the transfer of sediment and scour around series spur dikes in an experimental model using Flow 3d software. According to the comparison results, one can observe a good match between the results of the numerical and experimental models that the error rates of MAPE around the first spur dike, for U/Ucr ratios were, 0.75, 0.85 and 0.95 and were 9%, 13.79% and 14.10%, respectively. Then two protective spur dikes with various lengths (10 and 20 cm) were used in canal upstream and the effects of the presence of these two protective spur dikes simultaneously on the scour around the main spur dike were examined. In modeling done, increase in U/Ucr depth increases the maximum spur dike depth, so that with increase in U/Ucr by 26% (from 0.75 to 0.95), the increase in the maximum depth of the first spur was 51%, in the second spur dike 4 times, and in the third spur dike 116%. When the protective spur dike couple with various lengths is used simultaneously, and then these two protective spur dikes simultaneously drastically reduce the effect of the flow intensity to the wall and nose of the main spur dike. Moreover, the maximum depth of scour around the