The aim of this contribution is to improve the knowledge about factors controlling large wood deposition in the Czarny Dunajec River in Poland, combining direct field observations, a 2D numerical modelling approach and GIS. Numerical modelling is a powerful tool to analyse different aspects that govern wood deposition, because models can be used to run scenarios and can be analysed fully at any space and time. We used a numerical model to simulate different flood magnitude events and to analyse wood deposition in two different river reaches. Preliminary results gave information about sites of preferential wood deposition, wood retention capacity and relationships with the river morphology. We found contrasting patterns regarding wood retention capacity in the single-thread and the multi-thread channels. We observed that the deposition of wood is not static but dynamic and significantly depends on the hydrological regime. The importance of flow depth in particular is confirmed by the fact that the elevation of deposited logs is strongly linked to the water level. Therefore, flood magnitude is the main factor controlling wood deposition.