Sediment transport in the aquatic environment is one of the complex two-phase problems in flow mechanics and sediment hydraulics. In this study, the interaction between water and sediment is explored using the SPH method and developed SPHysics2D in which the pressure values are calculated using the state equation. In this study, the non-Newtonian rheological model µ(I) is used for modeling the sediment phase where it is developed based on the properties of granular particles. Also, the effective pressure is used for the study of sediment behavior. The method used in this research is compared with the methods used by other researchers. The Owen equation is utilized to determine the effect of viscosity within the two-phase area. The developed method is evaluated by the dam break on a dynamic bed and then, the experimental model of submerged sediment column collapse is investigated in the aquatic environment. The results of the modeling demonstrate the capabilities of the developed code for the use in the flow and sediment hydraulics.