Article published in English

Article: Monitoring coastal morphological changes using Remote Sensing and GIS in the Red River Delta Area, Vietnam

SI SON TONG 1,5, THI LAN PHAM 2, KAVINDA GUNASEKARA 3, THI NHAN NGUYEN 4, JEAN-PAUL DEROIN 5

1 Institut de Technologie Spatiale (STI), Vietnam Académie des Sciences et Technologie (VAST)
2 Faculté de Géodésie, Hanoi Université des Mines et Géologie (HUMG)
3 Geoinformatics Center (GIC), Asian Institut de Technologie (AIT)
4 Institut de Géologie marine et Geophysis (IMGG), Vietnam Académie des Sciences et Technologie
5 Université de Reims Champagne-Ardenne, GEGENAA EA3795

Abstract

This paper shows the research of coastal morphological changes in Red river delta using Remote Sensing and GIS technique. Study was carried out to assess the intensity of erosion, deposition and sand bar movement in the study area. Satellite images of ALOS/AVNIR-2 and Landsat MSS, TM, ETM+ were used for the monitoring of coastal morphological changes over the period of 1975 to 2009. Band rationing and threshold technique was used for the coastline extraction. Tidal levels at the time of image acquisition varied from 1.47m to 2.72. Therefore, coastline from another image at a different tidal level in the same year was considered to get the corrected coastline by interpolation technique. A series of points were generated along the coastline from 1975 image and were established as reference points to see the change in later periods. The changes were measured in distances from these reference points to the other coastline. Positive values represented deposition to the sea and negative values are erosion. The research showed that maximum erosion was 23.77 m/y between 1975 and 1989 in GiaoThuy, Nam Dinh area.
Human activities, such as shrimp farming and mangrove cultivation have expanded land nearly 3.5 km in Red river mouth and 2.8 km in Thai Binh river mouth from 1975 to 2009. The sand bar movement of the deltas were characterized by their alternating location of coastline, rate of deposition and erosion. In the analysis, sand bars were converted into centerlines for calculation. It was found that the sand bars moved 186 m/year in Red river mouth and 195 m/year in Day river mouth. ALOS/AVNIR-2 and Landsat MSS, TM, ETM+ images were classified to determine land cover changes of the coastal zone over three periods of time.

KEYWORDS
Coastal morphological, coastline extraction, coastal erosion, sand bar movement