Erosion-deposition evolution characteristics of north beach in Yellow River Delta

The north abandoned lobe of the Yellow River Delta has become a kind of typical beach strongly eroded by waves after the Yellow River estuary changing to Qingshuigou flow path. However, the relationships between evolution characteristics and influencing factors of the beach erosion are not very clear to us. Accurate data about beach evolution were achieved by ten in-situ measurements which were taken from the abandoned lobe beach in the north of the Yellow River Delta from December 2008 to December 2009 meanwhile the weather and hydrology data were also collected. Based on these data, the beach evolution character and the relationships among influencing factors such as waves, storm tides, sea-level-rising, sea-ice and so on are analyzed. The results show that: (1) the north line of Yellow River Delta is at a strong-eroding state that the erosion rate can reach almost 56.6 cm per day and the erosion takes on a seasonal characteristic that the erosion is much stronger in spring and autumn; (2) the beach erosion-deposition process has a close connection with the hydrodynamic conditions that erosion and deposition appear alternately and a strong deposition can be caused by a storm tide surge; (3) sea level has the biggest rising rate while the beach erosion is not so obvious through which we can tell that the sea level rising has a little effect on beach erosion; (4) the sea ices which have a hydrodynamics-weakening function contribute a protective role in the beach; (5) the erosion-deposition process is not synchronous and does not just simply obey the law “erosion in winter and deposition in summer”.