Kariba Dam is a 128 m high double-curvature arch dam located on the Zambezi River at the border between Zambia and Zimbabwe. The dam is known worldwide for its impressive plunge pool scour hole of almost 90 m below the tailwater level, which is an unprecedented value in dam history.This paper presents a numerical study performed to assess both past scour and future scour potential at the dam site. Based on gate opening durations and bathymetric surveys since 1960, quasi-3D time-dependent numerical scour computations have been made to assess the scour potential of the gneiss rock for the next 50 years.The computations use the Comprehensive Scour Model (CSM) [Bollaert, 2004]. This model is physics based and allows predicting rock scour evolution with time for the main rock break-up mechanisms (rock mass fracturing, rock block uplift and peeling off of rock blocks along the wall). The model has been calibrated based on past flooding and the corresponding scour observed. Dynamic pressures at the pool bottom have been analytically determined and compared with values measured on a 1/65 scaled model of the dam and its plunge pool constructed at the Laboratory of Hydraulic Constructions of the Swiss Federal Institute of Technology (LCH-EPFL). The numerical model automatically adapts these values during subsequent scour formation by applying a 2D turbulent jet diffusion model, downstream of each of the gates separately. Main assumptions and outcomes of the numerical scour study are presented. It specifically focuses on the potential for future scour as well as on the potential beneficial influence of several proposed countermeasures against further scour formation.