Inland navigation networks are composed of several artificial canals, usually characterized by no slope. These canals are large-scale systems that can be accurately described by means of the nonlinear Saint-Venant partial differential equations. However, the lack of an analytical solution for these equations is one of the reasons why simplified models have been developed. In this work, the Integrator Delay Zero model is used to obtain the general input–output model for a canal with inflows and outflows along the water stream. An overlapping problem is discussed and a criterion choice is defined in order to obtain the general model. With regard to this criterion, a calibration step is needed, both to overcome the natural limitations of the s...