Currently, in Peru engineering is going through a period of computer revolution, which means that knowledge related to new technologies must be constantly updated, having as tools data processing programs and software to obtain accurate results and optimize the development time of hydraulic projects. The present research determined the optimization of the computational time and mesh size of an open channel using the 2D models of Iber and 3D of Flow 3D. Therefore, the methodology of the study identified a quantitative approach, type of analytical research and experimental design. Moreover, for the development of the research, the following variables were identified: mesh size, computational time, 2D and 3D modelling. At first, the channel was sectioned into 12 sections of different roughness and then simulated with two computers of different characteristics and finally performed a comparative analysis of the models. By correlating the measurement of computational time with the level of accuracy and precision of the mesh size, an optimal model could be obtained. Finally, the hydraulic response in 2D and 3D models maintains an acceptable margin. In brief, 2D models have a shorter computational time and high performance in hydraulic structures and 3D models boast greater computational time and high impact of detail sensitivity in suggestive phenomena.