Analysis of shoreline change in Cua Dai beach by using Empirical Orthogonal Function

Abstract

ABSTRACT Cua Dai beach, located in Hoi An town – Quang Nam province, has experienced serious erosion for the past few years with extremely high speed of shoreline retreat. Despite coastal erosion itself may not be that much problematic, it turns out to be serious problem since there is a large residential area right behind and a huge investment in tourism has been done. Generally, causes of erosion are among unbalance of sediment transport, storm surges and sea level rise. However, the rate of shoreline retreat in Cua Dai beach within the past decade is so aberrant and not likely to be explained by the above phenomenon alone. The goal of this study is to consider effective factors of this coastal erosion based on analysis of the recent progress of erosion using Empirical Orthogonal Function. As a result, the dominant factor for the long-term erosion is concerned to be the change of longshore sediment transport, which was caused by the decrease in sediment supply from Thu Bon River. Therefore, it is recommended to collect more data on sediment transport in the river system and study the relationship between coastal erosion and the change of sediment supply.