Distribution of suspended sediments and action of nearshore currents in the Xiangyun Island, Laoting County, Hebei Province

This paper is the result of marine geological survey engineering.

Objective There are high−quality natural fine sand distributed along the coast of Xiangyun Island in Hebei, which is a famous coastal tourist island. Simultaneous investigation and research on the concentration of suspended sediments and nearshore current in this area is of great significance to the ecological environment of Xiangyun Island and its nearshore engineering.

Methods The current velocity and flow direction of the sea area were continuously profiled by ship−borne Acoustic Doppler Current Profiler (ADCP), and the distribution of suspended sediments in the sea area was qualitatively discussed according to the backscatter intensity recorded by the instrument.

Results The survey results show that: (1) The current in Xiangyun bay is mainly parallel to the coastline, which has obvious reciprocation. The magnitude of flood current was obviously larger than ebb current, the flood current was gradually weakened along the shore direction, however the ebb current in the southwest of Xiangyun bay increased along the shore direction; (2) During the transition from flat tide to ebb tide in Xiangyun island sea area, the current turning starts from the bottom water, and the current turning and tide level change have certain lag; (3) The data of backscatter intensity shows that: there was a high concentration layer in Xiangyun bay coastal area, and the concentration increases along the shore direction, and the concentration of suspended sediment gradually decreases from northeast to southwest.

Conclusions Xiangyun island coastal waters under the action of the tidal current, suspended sediment along Xiangyun Island shoreline from northeast to southwest, is the main reason for the Xiangyun island in the northeast section erosion and the southwest section deposition.