The simulation of open-channel flows through emergent rigid vegetation is carried out, using the open-source TELEMAC-2D system. The aim of this study is to find an optimal representation of the flow resistance caused by emergent rigid vegetation for a wide range of flow rates in absence of calibration data for the highest flows. Two strategies of flow resistance representation are compared: (1) the vegetation, in addition to the bed friction, is implicitly considered in a flow resistance coefficient; or (2) the vegetation is explicitly considered by being excluded from the computation domain. Results emphasize that the explicit representation is the more accurate solution for computing both flow depth and velocity, but field data are generally not available. The uncertainty observed on the water depth with the implicit representation is higher than for the explicit representation, but it can be reduced by using more evolved resistance coefficient.