Spur dikes (SD) are installed along the outer bank of a river to control river bank erosion. The first SD is more susceptible to failure due to toe scouring. A protective spur dike (PSD) is an effective measure to reduce the scouring around the nose of the first SD. In this study, experiments were conducted to determine the optimal location and height of the PSD to minimize scour depth at the nose of the first SD. The results indicate that the maximum scour depth depends on the height and distance of the PSD from the first SD. The best performance was observed when the ratio of PSD height to flow depth (HP/y) was 1.25, and the ratio of the PSD distance from the first SD to flow depth (XP/y) was 1.25. Scour depth at the nose of the first and second SDs was reduced by 54% and 32%, respectively. These findings suggest that PSDs can significantly reduce scour depth, thereby enhancing the effectiveness and stability of SDs.
