Coastal processes assessment of mainland kedah and langkawi island shorelines: A case study

The wave, wind, and tidal processes are part of the complex dynamic system that play a crucial role in shaping the coastal and marine environment Understanding these processes in a particular area is essential for predicting coastal changes, managing coastal resources, and developing strategies for climate adaptation. The present study investigates the wind, wave, and tidal climates along mainland Kedah and Langkawi Island shorelines which cover around 440 km. Wind and wave climates were assessed based on long-term data of 29 years (1991-2019) at two locations namely, northern and southern points, while the tide climate was investigated over two months period through 6 stations distributed along the study area. Results revealed that the predominant wind came from the northeast and northwest directions with maximum speeds of 16 m/s and 14 m/s at the northern and southern points, respectively. In terms of wave climate, the predominant wave direction was northwest with maximum wave heights of 3.5 m and 2.8 m at the northern and southern points, respectively. Wave condition was found to be calm during the inter-monsoon period with a calm percentage of more than 90%. This value reduced to around 58% during the southwest monsoon. The study area experienced mixed tide but predominant by semi-diurnal tide. Tide records showed that station TG5 that was located on the east coast of Langkawi Island experienced the highest tidal range of 2.55 m, while the lowest (2.09 m) was noticed to be at TG2 station which was located at the middle point of the mainland Kedah shoreline. Authors believe that the findings of this study are crucial for effective coastal management and planning where stakeholders can better anticipate coastal changes, optimize resource management, and develop adaptive strategies to mitigate the impacts of climate variability.