4. Summary: how to choose the right model

Although conventionally referred to as hydraulic models, both physical and numerical models are able to reproduce not only the movement of water, but also the transport of a substance diluted in water, with any corresponding density effects, as well as the interaction of the fluid with the bed's constituent elements, i.e. solid transport. Physical and numerical models overlap, albeit in very specific areas. The split currently observed is summarized in table 1 .