Bed features have an important effect on frictional characteristics and turbulence in the flow and have a direct effect on sediment transport. Observations of hydrodynamics and bedform evolution are presented at 2 locations in the Dee estuary. Hydrodynamics and turbulence are controlled by tides which has a range of about 10 m. Some wave events were mainly recorded at the western location because of a higher exposure to western waves. In the Hilbre channel (STABLEIII tripod), the bed evolution is dominated by scour under the frame and ripple formation is not evident. This could be also attributed to the high concentration of cohesive material and large tidal velocities. In the Welsh channel, velocities were lower and no evidence of scour was found.