Laboratory measurements of surf and swash zone hydrodynamics were recorded in the US Army Corps of Engineer's Large-scale Sediment Transport Facility and compared to 2 numerical models to investigate the model's ability to predict water surface elevation and wave orbital and swash velocities. One numerical model relies on the depth averaged non-linear shallow water equations (ID), while the second is based on the full Navier- Stokes equations and uses a volume of fluid approach in the numerical solution (2D). Both models were able to adequately predict the sea surface elevation across the inner surf zone. In general, there was strong similarity between both models and observed velocities with some velocity over prediction during bore passage. Similarity between the 2 models and only small differences between vertically separated near bed (z = 1, 3 cm) velocity time series suggests that the flow in the swash zone is nearly depth uniform for most of the swash cycle implying a thin boundary layer. The 2D model improves on the ID model by allowing for predictions of this boundary layer structure in addition to a more accurate representation of wave breaking and shear stress calculations based on near bed velocity gradients.
