In this thesis, a coupled hydrodynamic, morphodynamic and plant growth model is reviewed. The goal of this model is to simulate plant colonization and channel formation on an initially flat or ascending substrate in a tidal landscape. To be able to simulate these biophysical processes on a small enough scale (while still using the same spatial scales), the model is implemented on a graphics processing unit. The focus of this thesis lies on the grid and space-discretisation and the processes involved. In the simulation presented in this thesis, the finite difference discretisation on a collocated grid is replaced by a finite volume discretisation on a staggered grid. Besides, the current model assumes that there is a constant input of water throughout the whole computational domain and sediment deposition depends on the water height. In order to make the model more realistic, the simulation of tidal action is added. Afterwards, a transport equation is added, allowing to simulate the transport of substances. When implementing these improvements the features of a graphics processing unit need to be taken into account. In the end, the advantages and limitations of our model are discussed extensively.