Abstract: One of the major problems in river engineering is the erosion of the bed river due to improper removal of sand and gravel from the river bed. Therefore, investigating the hydraulic condition of the river is necessary in order to prevent the bed erosion of the rivers. Nowadays, With respect to the limitations of laboratory models and economical problems, usage of numerical models in hydraulic engineering problems is growing. All numerical models make some form of approximations to solve the basic principles of conservation of mass, energy and momentum, which form the basis of fluid mechanics. In this paper, after explaining the destructive effects of mining an inappropriate pit in the bed river and giving a brief introduction about the physical model which is made for investigating the variation of bed profile due to a mining pit, the capability of a leading one-dimensional hydraulic engineering software (HEC-RAS) in modeling the bed variation of the experimental model is investigated. The simulation results were also compared to experimental data and the comparison showed a good agreement between simulated and experimental data. Therefore, this numerical model can be so useful to help solving the mining problem which will occur due to improper removal of sand and gravel from river’s bed.