TY - JOUR
T1 - Seasonal Variation of Morphology and Sediment Movement on Nha Trang Coast, Vietnam
AU - Thanh, Tran M.
AU - Tanaka, Hitoshi
AU - Mitobe, Yuta
AU - Viet, Nguyen T.
AU - Almar, Rafael
N1 - Funding Information:
This study was funded by a National research project “Study on hydrodynamics and sediment transport regime in estuarine and coastal zones of Nha Trang bay, Khanh Hoa province” of Ministry of Science and Technology (MOST), Vietnam. This study was also supported by the project “Investigate morphodynamical processes and propose applied solutions to recreate and upgrade the Nha Trang Coast, Khanh Hoa province in the context of climate change” (NDT.24.FRA/16, research period: November 2016 to May 2019), and hence the authors sincerely thank the principal investigator, Prof. Nguyen Trung Viet, Thuyloi University. We would like to thank Thuyloi University, Vietnam for their kindness in the provision images from video-camera monitoring. In addition, a thank you to Mr. Duong Cong Dien of Institute of Mechanics, Vietnam, who kindly provided necessary information regarding the simulated wave data.
Publisher Copyright:
© Coastal Education and Research Foundation, Inc. 2018.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - The Nha Trang beach, an embayed sandy beach located in the southeast of Vietnam, is a tropical touristic coastal environment that is being threat by persistent shoreline retreat. In order to investigate the processes underlying this erosive pattern, 1.5-years of video imagery, obtained from a local video system, was analyzed. Video products such as shoreline position and surf zone width (extracted from time-averaged images) were used to identify patterns of shoreline variability (using empirical orthogonal function-EOF) and investigate the link between the seasonal variations in the wave forcing and longshore sediment transport. Results indicate that shoreline retreat occurs essentially during the winter season, when energetic northeast monsoon waves dominate. The recovery phase (shoreline advance) was found to occur during the summer season, when milder south/southeast wind waves dominate. Shoreline variability was further investigated using EOF analysis and results show that the first mode, which explains 89% of the observed variance, corresponds to the seasonal longshore shoreline variations. This EOF mode was found to strongly related to the winter and summer monsoon seasons, thus reinforcing the role that seasonal changes in the wave climate play on the shoreline variations. Finally, the net of longshore sediment transport in Nha Trang beach was investigated using seasonal and monthly depth of closure (Dc) information, rather than a single fixed value of this parameter. The results highlight that the use of monthly or seasonal Dc values allow to capture the seasonal variations in the wave climate, thus providing more realistic patterns of sediment transport in this coastal area.
AB - The Nha Trang beach, an embayed sandy beach located in the southeast of Vietnam, is a tropical touristic coastal environment that is being threat by persistent shoreline retreat. In order to investigate the processes underlying this erosive pattern, 1.5-years of video imagery, obtained from a local video system, was analyzed. Video products such as shoreline position and surf zone width (extracted from time-averaged images) were used to identify patterns of shoreline variability (using empirical orthogonal function-EOF) and investigate the link between the seasonal variations in the wave forcing and longshore sediment transport. Results indicate that shoreline retreat occurs essentially during the winter season, when energetic northeast monsoon waves dominate. The recovery phase (shoreline advance) was found to occur during the summer season, when milder south/southeast wind waves dominate. Shoreline variability was further investigated using EOF analysis and results show that the first mode, which explains 89% of the observed variance, corresponds to the seasonal longshore shoreline variations. This EOF mode was found to strongly related to the winter and summer monsoon seasons, thus reinforcing the role that seasonal changes in the wave climate play on the shoreline variations. Finally, the net of longshore sediment transport in Nha Trang beach was investigated using seasonal and monthly depth of closure (Dc) information, rather than a single fixed value of this parameter. The results highlight that the use of monthly or seasonal Dc values allow to capture the seasonal variations in the wave climate, thus providing more realistic patterns of sediment transport in this coastal area.
KW - Nha Trang Coast
KW - Vietnam
KW - beach erosion
KW - longshore sediment transport
KW - seasonal shoreline variation
KW - video monitoring
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U2 - 10.2112/SI81-004.1
DO - 10.2112/SI81-004.1
M3 - Article
AN - SCOPUS:85058863393
VL - 81
SP - 22
EP - 31
JO - Journal of Coastal Research
JF - Journal of Coastal Research
SN - 0749-0208
IS - sp1
ER -