Double Master of Science in Hydraulic Engineering (Civil Engineering and Geosciences) and Applied Mathematics (Electrical Engineering, Mathematics and Computer Science) - It is of importance to know how the water is behaving in rivers due to the dangers, such as flooding and eroding of land, it can bring with it. Present day we are still reshaping rivers, building structures in rivers or adjusting them, which results in changes in the hydrodynamics and morphology. In order to obtain more insight in the consequences of these adjustments, it is convenient to use a numerical model to simulate the river hydrodynamics. For the last decades numerical models have been developed that are able to simulate hydrodynamics. Currently, new software packages are proposed that are more efficient in predicting this. Two of these new software packages are D-Flow Flexible Mesh (FM) and 3Di. Whereas the first is especially designed to model the hydrodynamics of rivers and other flows such as in estuaries, the latter is mostly used for the simulation of flooding of land (for example due to dike breaches). The usage of numerical model applications results usually in many choices that have to be made. Based on these choice there are considerations that need to be taken into account. Both these choices and considerations will have influence on the river hydrodynamics. With two new packages available that can simulate hydrodynamics, the choices and possibilities for each package should be clear. When multiple numerical model applications are considered the similarities and differences should be known. The aim of this thesis is to indicate which considerations and consequences for simulations, that follow from the choices in numerical model applications, are important for the suitability of results given a specific problem.