for the calibration and validation of the Luneplate tidal polder numerical model, two field investigations were carried out on the 14th July and 21st August 2015. Data on the flow velocity, water salinity and turbidity were obtained during one complete tidal cycle, both on the Luneplate tidal Polder and on the adjacent Lower Weser River. The results confirm the ebb-dominated tidal currents of the Weser Estuary, as high velocities, up to 135 cm/s were recorded during the Ebb period. In contrast to the Lower Weser, the Luneplate tidal polder is flood-dominated. The velocity peak was recorded here around high water level and maximal velocity values of 52 cm/s and 78 cm/s were respectively measured at the entrance of the secondary main tidal channel and near the tidal polder flood barrier. The variation of the freshwater discharge as well as the tidal range during the two surveys had affected the salt distribution and allowed to clearly draw the dependency of the tidal polder salinity to the flood salinity of the adjacent Lower Weser River. The averaged salinity values of the whole study area amount to 5–8 ppt during the flood and to 11–13 ppt for the ebb tide. The increase of the flow velocity during the flood tide led to a sediment redistribution within the water column. Average suspended sediment concentrations from 82 mg/l to 1,012 mg/l were characteristic of the flood tide, while values from 60 mg/l to 1,113 mg/l were obtained from the ebb measurements. The results also revealed that a more important amount of sediment flow into the tidal polder than out. Those sediments are mostly made up of silt, with up to 16 % organic matter content.