Author(s): Vu Huong Ngan; Nguyen Nhat Minh; Nguyen Khanh Linh; Dinh Nhat Quang; Ho Sy Tam; Nguyen Trung Viet
Linked Author(s): Trung Viet Nguyen
Keywords: Coastal change analysis; Satellite images; Digital shoreline analysis system; Quang NAM province
Abstract: Coastal change analysis is one of the controversial issues in water resources fields since this greatly impacts coastal management. The case study of this research is the coastline at the Northern Cua Dai river mouth, where witnessed the significant morphological change in recent years. To approach coastal change analysis in this region, the authors adopted DSAS - Digital Shoreline Analysis System, an addi-in to ArcGIS software, to calculate rate-of-changes statistics in the long-term process. Satellite scenes in 1990,1995,2000,2005,2010,2015,2017 and 2019 were collected and processed to extract representative coastlines, which were the inputs to implement DSAS calculation. The results indicate the case study experience both erosion and accretion phenomenon, where 8 km coastline in Hoi An had been eroded most seriously with the highest rate reached to -45 m/yr and retreat distance was more than 1 km. Importantly this methodological approach provides not only visual coastline change information (Net Shoreline Movement, End Point Rate, Linear Regression Rate) but also relating indicators (Uncertainty, Standard Error, Correlation Coefficient and Confidence Interval) for checking the accuracy of the application. Three primary reasons leading to the severe situation of erosion and accretion in the Northern Cua Dai river mouth are natural factors, constructions and tourism industry. The local authorities can base on the results of this research to offer suitable and optimal methods in cover the damage in this area.