The project objective was to assess the drainage for the post project scenario (High embankments, roads, canals etc.), BWDB in 1986, sought an expert opinion of the Bureau of Research Testing & Consultation (BRTC) of Bangladesh University of Engineering & Technology (BUET), Dhaka on the planning and design of Irrigation and Drainage System of the Project. The BRTC team felt the necessity of a mathematical model study of the project area to use the flood routine technique.

The modelling was carried out alongside the North West Region Modelling activities of the Surface Water Simulation Modelling Programme, Phase-II. The model was calibrated and verified for the period of 1990 to 1992.

Application of the model was primarily demonstrated by running the model with a project scenario, where a 3-day 25 year rainfall would occur after a full irrigation applied over the project area under hydraulic boundary conditions in 1991. A smaller model having boundary at the project boundary was developed for monitoring purposes. The TPDM was joined with the lower Atrai-Bangali system to see an effect of post project runs inside and outside the TPDM area.