Water quality models are important decision support system tools for water pollution control, study of the health of aquatic ecosystems and assessment of the effects of point and diffuse pollution. However, water quality models are usually comprehensive software, which are usually not easy to learn and apply. Thus extensive training is needed before scientists and engineers can use most of the water quality models effectively. In this study; a new, easy to use and simple stream water quality modelling software is developed. The model underwent an extensive testing period that includes education/training oriented applications and a real world application as well. The software is easy to learn and the model is simple enough to be used in advanced undergraduate and introductory graduate level courses in aquatic sciences and environmental science, engineering or management programmes. It can also be used for institutional training in state offices that arc dealing with water pollution control and integrated water management as well. All the modelling system is developed according to free/open software philosophy so that advanced level users such as trainers are able to modify it according to the training/institutional needs.