Erosion and its influencing factors of surface sediments nearshore of Yancheng, Jiangsu

The coast of Yancheng, Jiangsu is one of the largest silty muddy coasts in China and has been in an erosional state in recent years. The sediment erosion are one of the important factors affecting coastal erosion, for which this systematic research was carried out yet. The micro-erosion system (U-GEMS) was used in our field experiment on the undisturbed sediments in the intertidal and subtidal zones in 2023, and the influencing factors were discussed. Results show that the critical erosion shear stress of intertidal sediments was between 0.2 and 0.6 N/m2, and the erosion rate under a shear stress of 0.6 N/m2 was between 0.053 and 0.263 g·m−2·s−1. The critical erosion shear stress of subtidal sediments was between 0.3 and 0.69 N/m2, and the erosion rate under a shear stress of 0.6 N/m2 was between 0.051 and 0.078 g·m−2·s−1. Clay content was the main controlling factor of sediment erodibility and erosion pattern. Moisture content and dry bulk density had a significant impact on the erosion characteristics of cohesive sediments, but had little impact on the erosion of non-cohesive sediments. Affected by factors such as sedimentary environment and hydrodynamic characteristics, the erodibility of the intertidal zone in the study area was significantly higher than that of the subtidal zone. The research results are helpful to enrich the theoretical research into nearshore erosion and deposition evolution, and provide guidance for coastal erosion protection and the sustainable development of the coastal zone.