This research investigates the hydrodynamic and morphodynamic behaviour around the Xstream groyne compared to traditional groynes. Implemented as a pilot in the IJssel River near Kampen, the Xstream groyne consists entirely of interlocking concrete blocks that creates a steep permeable structure with a 1:1 slope. Field measurements revealed unusual sedimentation behaviour, including the formation of a sediment ridge or “sediment line,” which differs from the scour-dominated patterns typically observed at traditional groynes. To explain this, multibeam, ADCP and float tracking measurements were analysed and a 3D CFD model in ANSYS Fluent was constructed. Results showed that the Xstream groyne produces weaker, elongated recirculation zones and redistributed erosion and deposition patterns. The sediment line forms in low-velocity zones influenced by a slow, counter-clockwise eddy, highlighting the dominant role of the groyne’s steep slope over its porosity. These findings demonstrate that the Xstream groyne fundamentally alters local flow and sediment regimes.