The Yangtze River is one of the largest rivers in the world and the longest one in Asia. Its estuary forms an important entrance for shipping, but is also a key ecological system. Especially the inter-tidal flats are valuable habitats. The health and integrity of the estuarine tidal flat are however under pressure due to anthropogenic influences upstream (e.g. the Three Gorges Dam) and in the estuary (navigation works). The processes responsible for the dynamics of tidal flats are still not fully understood. Although it is clear that tides, river run-off and waves steer the sediment transport, the full non-linear interaction needs further research. In this paper, the seasonal variation of the bed level is analysed, using a data set of tides, wind and river run-off.