Abstarct: Abstract In the present experimental study, the simultaneous use of bed sill and sacrificial piles around the circular pier was studied, to investigate whether this combination could be effective in reducing scour depth. First, the concept of scouring phenomenon was explained. In fact, scouring is known as a general phenomenon in nature that is related to the movement of particles from the initial location to another location. The flow field around the pier needs to be known, investigated and researched in order to be able to express how scouring around the pier causes the failure of many bridges and also how this phenomenon can be controlled. Complex parameters interactions have made it necessary to know the state of sediment entrainment. To achieve the main aim of the present study, 14 experiments were conducted. For this purpose, a circular cylindrical PVC with a diameter of 6 cm was used as a pier. Two triangular and transverse arrangements with the numbers of 3 and 5 piles were used for sacrificial piles. Two wedge angles of 30° and 60° were considered for the triangular arrangement. In this study, a 1-cm-thick PVC as wide as the channel, flush with the bed and extended to the floor of the channel, was used as the bed sill. The bed sill was attached to the back of the pier. Uniform sediments with a mean diameter of 0.77 mm were used to investigate scouring and sediment entrainment. The results obtained in this study showed that the combination of bed sill and sacrificial piles is quite effective for scouring control, and in the best configuration can reduce scouring depth to 51.1%. Therefore, the use of this combination can be recommended. The flow-sediment interaction around the pier is obvious, and it is necessary to study it. Since it is important to know the state of sediment entrainment around the pier, therefore, the coherent turbulent flow structure around the best combination of bed sill and sacrificial piles was investigated, and its effect on the bed scouring pattern was studied. It was found that the CBSW3 and CBST330 tests have the best combination of transverse and triangular sacrificial piles with bed sill, respectively. These two tests reduce scour depth to 40% and 51.1%, respectively. The 3D velocity fluctuations were measured using a down-looking Acoustic Doppler Velocity meter (ADV) around these tests. The three-dimensional analysis of the bursting process (octant analysis) was used, and the occurrence and transition probabilities and inclination angle of the bursting events, were calculated. Various turbulent flow characteristics, such as velocity profiles, turbulence intensities, turbulent kinetic energy and Reynolds shear stresses, were also considered. For comparison, the results for the unprotected pier (test C1) were also included. The results obtained in this study confirmed the quite effective effect of the combination of these two countermeasures in reducing the scour depth.