In semi-enclosed areas, as bays and estuaries, a strong feedback exists between benthic fauna evolution and sediment dynamics. So-called “ecosystem engineers”, benthic populations modify suspended matter deposition by bio-filtration and increase sedimentation by bio-deposition of pseudo-feces. In turn, hydro- and sediment dynamics directly impact the fauna environmental conditions. However, the complexity of this feedback remains extremely difficult to be addressed in nature. Therefore, new experimentation in laboratory have been carried out to investigate interactions between benthic fauna (Crepidula fornicata) with mud/sand dynamics under waves and currents. Measurements of hydrodynamics and turbidity at high-frequency enabled to quantify the relative influence of key processes driving sediment dynamics associated with benthic populations, as bio-filtration and flocculation.