Modeling of pollution transport and dispersion is a key methodology for assessing water quality, particularly in the context of the impact of pollutants on the ecological status of water bodies. This study uses the HEC-RAS software package to simulate the transport of pollutants in the Drinjača River, taking into account the BOD5 (biochemical oxygen demand for 5 days) parameterIn this study, the discharge of pollutants into the Drinjača River was analyzed with the aim of monitoring the propagation of the dissolved oxygen concentration wave, particularly focusing on the maximum values and the time at which they are reached.The differences in pollution transport were also examined based on varying degradation and longitudinal dispersion coefficients. The results of the simulations can serve as a basis for future water quality management in the area and as a tool for predicting ecological changes due to pollution.