Wave climate at Cua Dai - Hoi An seashore and its impact on beach erosion

Abstract

The wave climate at the Cua Dai – Hoi An seashore was analyzed based on the results of wave simulation via mathematics models for the whole East Sea and the Cua Dai – Hoi An seashore in 8 years (2009-2016). The simulation results were adjusted and verified with predicted wave data from NOAA and observed data from the area under study.
Results from the wave analysis show that the waves in the Cua Dai – Hoi An seashore come in two distinct seasons. During the Northeasterly wind season, the waves chiefly move in the NE and NEE directions, appearing in considerable heights with the maximum of 4.7m, thus causing serious erosion to the Northern coastline of the Cua Dai – Hoi An seashore. During the southwesterly wind season, the waves chiefly move in the SEE direction, appearing with the maximum height of only 2m. This season is also the time for mud and sand from the Cua Dai estuary to be moved by the current along the shore to reinforce the Northern coastline. However, due to a shortage of mud and sand, there occurs imbalance in the reinforcement, leading to increasing erosion of the beach north of the Cua Dai estuary.