Topographic datasets are one of the most important parameters for hydro-morphodynamic simulation. Mostly simulation is performed using local high precision datasets which are more difficult or even impossible to obtain at broad scales such as Europe or the globe. So how good are globally available satellite-based datasets? Hence, the main focus of this research is to compare local high precision datasets and global topographic datasets in hydrodynamic modelling to understand the effectiveness/limitations of these global datasets. The case study considers the Wash, UK where there is a local high precision Lidar dataset with which we compared and validated the results with the global elevation datasets of SRTM [1] and MERIT [2] and Delta DTM [3]. The tidal level variation for the global datasets (SRTM, Merit) compared with the local LIDAR data has a difference ranging from 10 cm to 1 m and Delta DTM has a difference ranging from 5 to 10 cm at the observation locations. Findings of the simulation highlight qualitative similarities in tidal water level using global datasets while exposing limitations in detail such as nearshore topography.