This paper presents a numerical study on erosion and deposition of a sandy beach installed with a breakwater bearing spill holes, aiming to understand its performance in erosion reduction. The two-dimensional (2D) governing equations for the water-sand mixture are solved by the VOF method and other techniques. The numerical approaches are validated against experimental data for wave propagation on an impermeable beach with a breakwater, scour underneath a pipeline, scour in front of a breakwater, and erosion and deposition of a sandy beach. On ...