Response of sediment dynamics and morphological evolution to extreme storms in the mudflat of Yellow Sea

The Jiangsu coast, located along the Yellow Sea, is significance region on the eastern coast of China. Storm events can trigger intense current and wave, leading to significant variations in morphology of mudflat. However, the response of mudflat morphology to storm events has not been fully explored due to limited field observations. Based on Delft3D model, a three-dimensional coupled model of current-wave-sediment-topography was developed to simulate the response of mudflat morphology to storm events and investigate the effect of storms with varying paths and intensities on mudflat evolution. Mudflat exhibit interlaced areas of erosion and accretion, with accretion predominantly occurring in supratidal zone and erosion primarily happening in intertidal and subtidal zone. A comparison of mudflat morphology before and after storm reveals that alongshore current is the dominant factor affecting sediment transport. Radial sand ridge has an obstructive effect on the transport of eroded sediments during storms of varying paths and intensities. Transport direction of sediments from the south and north are changed because of barrier effect of radial sand ridge, resulting in spatially asymmetric erosion-accretion pattern. The coupled model developed in this research could offers theoretical foundation for elucidating the response mechanisms of mudflat topography in the context of global changes. • Alongshore currents induced by storm events cause coastal erosion. • Radial sand ridge has obstructive effect on the transport of eroded sediments. • Radial sand ridge causes asymmetric geomorphic changes.