International Journal of Environmental Science and Development

Abstract—Tg. Piai, located on the southern tip of west Malaysia in Johor, is subject to critical coastal erosion on the east side of the headland, and, as a consequence, severe loss of protected mangrove coastline has been observed over the past 20 years. Various triggers for this erosion have been proposed, all being linked to the extensive developments of the region, and the increase in marine activities in the waters of Singapore Strait. In this study, impacts on the regional (ambient) wave field, by the presence of ships in the Strait of Singapore, are investigated. Waves are partially reflected off the hulls of the ships, and the extensive presence of ships in the Strait of Singapore thus manifests itself as a blocking of the ambient wave field, resulting in a wave climate near Tg. Piai that depend on the congestion of ships. The integrated effect of the ship hull-induced wave reflections on the ambient wave field is evaluated by using the numerical modelling tool MIKE 21. Information on the number, the positions and the sizes of the ships are determined from satellite images. It is found that the impacts of ship hull-induced wave reflections on the near shore wave field at Tg. Piai are significant, and, in particular, that the impacts on near shore wave periods are pronounced. The MIKE 21 model predicts significant reductions in the wave periods at Tg. Piai when including the ships. These changes in the wave periods can explain the changes to the coastal morphology observed at Tg. Piai, including the coastal erosion, from the notion that the longer waves in the wave spectrum tend to push sediment in the coastal profile onshore, whereas the shorter waves moves sediment seaward.

Index Terms—Coastal stability, environmental impact, Johor, wave reflection.

Jacob Hjelmager Jensen was with Technical University of Denmark. He is now the Technical Director is with DHI Water and Environment (M) Sdn Bhd, Kuala Lumpur, Malaysia (e-mail: jhj@dhigroup.com).
Juan C. Savioli and Khairunnisa Saaban are with Coastal and Marine Department, DHI Water and Environment (M) Sdn Bhd, Kuala Lumpur, Malaysia (e-mail: jcs@dhigroup.com, kns@dhigroup.com).

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Cite: Jacob Hjelmager Jensen, Juan C Savioli, and Khairunnisa Saaban, "The Impact of Wave Blocking from Ship Hulls on the Stability of Tg. Piai Coastline," International Journal of Environmental Science and Development vol. 7, no. 7, pp. 542-545, 2016.