This study aims to investigate the interaction between the flow and rocks (clasts) and associate this interaction with the depositional patterns of incoming sediment around the rocks at high and low relative submergence regimes. Flow measurements were performed in the vicinity of the clasts placed atop a flat, porous bed of a flume for high and low relative submergence conditions via Acoustic Doppler Velocimetry (ADV) and Large Scale Particle Image Velocimetry (LSPIV). The velocity measurements showed that a stagnant region developed in the clast wake for high relative submergence but the clast effects did not reach the free surface. Instead, for low relative submergence the effects of the clasts were felt at the water free surface and a horseshoe vortex developed around the clasts. Typically, incoming sediment deposited within the clast wake for high relative submergence, and at the upstream face of the clasts for low relative submergence.