Seawater desalination becomes crucial as fresh water scarcity increase and is an alternative water source. Uncontrolled brine discharges into the ambient seawater having excess salt, have negative impacts on the marine ecosystems. Numerical modeling is an appropriate tool for impact assessment of brine discharges. In this study, the near-field dilution of brine discharges was simulated, and the behaviors of dense pollutant jets were analyzed using CORMIX (CORMIX2), which can model of negatively buoyant plumes. The effects of different parameters such as total effluent discharge, ambient current, port number and port diameter on the near field dilution of dense discharges were examined by different scenarios in Samsun Bay. In the Samsun Bay coastal waters, salinity and temperature during one year were measured. These measurements show the realistic physical characteristics of coastal waters into which effluent has been discharged. Based on the conditions of the ambient seawater, the diffuser must be designed in the legal regulations. The effects of the different parameters on the near-field dilution of brine discharges should be considered in the optimal design of diffusers. Therefore the sensitivity analyses of total effluent discharge, ambient current, port number and port diameter are presented.