Although estuaries typically exhibit high suspended sediment concentrations (SSC), only a few studies have investigated how the impact of SSC on density can affect the exchange between rivers and coastal waters. Here, we use numerical models to quantify the impact of SSC on water exchange based on an estuary with large SSC and tidal range. We found that the non-consideration of SSC leads to large differences in the exchange of water that could lead to the over-quantification of water transport.