The present thesis focuses on the investigation of the inuence of bathymetry induced 3D eects on the sound levels and the derivation of simple to apply scaling laws for unmitigated as well as for mitigated pile driving scenarios. For this purpose, a hybrid pile driving noise model based on the nite element method and the Parabolic Equations (PE) is developed. The nite element model is used to derive the starting eld for the computationally more ecient PE model, which is able to include horizontal diraction and therefore allows for the investigation of bathymetry induced 3D eects. In addition, noise mitigation measures such as bubble curtains can be included in the model. The developed modelling approach is validated with measurement data from three dierent wind farms including unmitigated and mitigated pile driving. The location of the occurrence of bathymetry induced 3D eects is investigated with data of three real-life scenarios with dedicated water depth proles. It is shown that sand dunes oriented in propagation direction are the main cause of 3D eects at the considered ranges. Furthermore, the inuence of the sample size of the bathymetry data and the inuence of uncertain acoustical parameters of the sea oor on the 3D eects are nvestigated and discussed. The modelling approach is used to derive scaling laws for the inuence of the strike energy, the pile diameter, the ram weight, and the water depth on the sound exposure level and the peak sound pressure level. This is done for mitigated and unmitigated scenarios.