Seasonal Variation of Morphology and Sediment Movement on Nha Trang Coast, Vietnam

Tran M. Thanh, Hitoshi Tanaka, Yuta Mitobe, Nguyen T. Viet, Rafael Almar

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)22-31
Number of pages10
JournalJournal of Coastal Research
Volume81
Issue numbersp1
DOIs
Publication statusPublished - 2018 Sep 1

Keywords

  • Nha Trang Coast
  • Vietnam
  • beach erosion
  • longshore sediment transport
  • seasonal shoreline variation
  • video monitoring

ASJC Scopus subject areas

  • Ecology
  • Water Science and Technology
  • Earth-Surface Processes

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