IMPACTS OF STORM ON WATER AND SEDIMENT TRANSPORTATION THROUGH TIDAL CREEKS OF COASTAL WETLANDS: A CASE FROM EASTERN CHONGMING TIDAL FLAT, YANGTZE ESTUARY

In order to investigate the impacts of storm event on water and sediment transportations through tidal creeks of coastal wetlands, in-situ measurements were carried out in a typical tidal creek in the Eastern Chongming tidal flat under both the conditions of calm weather and stormy weather (during the typhoons of "Yagi" and "Rumbia"). The facts show that the average wind speed near the shore during typhoon period was 3~4 times higher than that in calm weather, while the significant wave height increased by 7~15 times. During the storm event, mudflat and saltmarsh at the tidal front were strongly eroded, surface sediment coarsened for 1~2.1 times, suspended sediment concentration increased by 3~11 times, the sediment transport flux per unit width for each tidal cycle increased by 4~33 times, and the net sediment flux per unit width for each tidal cycle increased by 8~17 times. The transportation of water and sediment during flood and ebb tides under storm weather conditions were much greater than those under calm weather conditions. The net sediment flux was moving towards saltmarsh flats and deposit there due to attenuation of wave, retarding of current flow and trapping of mud.