Unionid mussels are important in freshwaters because of their roles as ecosystem engineers (e.g., water quality and nutrient regulation). Water flow plays a significant role in the life of mussels, facilitating several processes including reproduction and food intake. Excessive hydrodynamic forces, however, are also responsible for the dislodgement of mussels, especially when mussels engage in feeding and reproduction and are exposed above the sediment-water interface. This research presents both field and computational fluid dynamics (CFD) modeling to understand the advantages and disadvantages (i.e., trade-offs) of mussel orientation at different water speed. Freshwater mussels were collected from rivers in Southern Ontario, and the species and orientation, relative to flow in the river, was recorded. For CFD modeling, COMSOL Multiphysics software was used to model these interactions with Lampsilis siliquoidea. Higher angles of attack and vertical angles have higher drag coefficients. The significance of this research is to provide a broader understanding of the impact of hydrodynamic forces on living organisms in moving fluids. In addition, the evolutionary history of freshwater mussels will be better understood relative to water flow characteristics.