Backward Erosion Piping (BEP) is one of the critical failure mechanisms for levees. Current assessment methods of BEP are either empirical or simplistic, leading to conservative and potentially costly flood protection designs. This study aims to improve the understanding of BEP through scale model experiments that focus on the role of vertical seepage forces on erosion criteria. The study will include experimental and numerical modelling to refine BEP erosion descriptions and to contribute to the development of reliable prediction methods.