Abstract: Reliable and safe operation of a coal-fired power plant is strongly linked to freshwater resources, and environmental problems related to water sources and wastewater discharge are challenges for power station operation. In this study, deals an evaluation on basis of wastewater pollutant vector is reported of the environmental impact of residual water generated and discharged in Jiu River during the thermoelectric units operation of the Rovinari, Turceni and Craiova coal-fired power plants. Wastewater pollutant vector Plane Projection is applied for assessing the water temperature evolution in the water flow lane created downstream of each power plant wastewater outlet channel. Simulation on the basis of an Electricity of France model, and testing validation of the results for thermoelectric blocks of 330 MW of these power plants, are presented.