RESPONSE OF COASTAL SEDIMENT TO THE HYDRODYNAMIC CONDITIONS IN THE FEIYAN BEACH IN THE NORTHERN YELLOW RIVER DELTA

Since the terminal reach of the Yellow River shifted to Qingshuigou in 1976, northern coast of the Yellow River delta has been wholly faced with an erosion situation due to the discontinuity of the river-supplied sediment, which has seriously threatened the safety of ecosystem environment and the Shengli Oilfield in this area. A comprehensive analysis is conducted based on the data of wave, tidal current and bedload which was observed during March-September 1987(wave) and April 2004(tidal current and bedload). Laws of the coastal sediment movement and response to the hydrodynamic conditions, the sediment transportation and the sediment supply have been studied and discussed. Results are as follows:①Tidal current can start up sediments in part of tidal-creek areas and rages between isobaths of 1.7m and 17m. And the sediment-carrying capability of wave is determined by the sediment distribution, wave energy and water depth. Also in the study area, sediments can bear wave motivity not more than waves with 3m height. ②The finer sediment which comes from the intertidal zone is an important supplement to the coastal bedload which lies in front of the tidal creek. It plays a significant role in maintaining the coast equilibrium profile or decelerating the erosion. ③Generally, sediments are mainly transported towards offshore, except in the tidal-creek inlets.