Integrated hydrodynamic and environmental assessment of Kuah coastal Area, Langkawi island: A framework for future coastal resilience

Abstract Coastal areas are increasingly affected by a combination of natural processes, human activities, and climate change, leading to several environmental challenges which require comprehensive management strategies for sustainable development. This study provides a comprehensive assessment of the Kuah town coastal area on Langkawi Island, Malaysia, focusing on current hydrodynamic and environmental conditions. The assessment covers current flow, wave features, sediment transport, shoreline conditions, flora and fauna, and the water quality. The study further utilized Mike 21, a two-dimensional hydrodynamic model, coupled with spectral wave and mud transport packages for the numerical modeling. The current flow simulation was conducted over a 16-day spring-neap cycle under southwest monsoon conditions, while wave and sediment transport simulations were evaluated under northeast, southwest, and inter-monsoon seasons. Other assessments were conducted based on the collected data from the study area or from the state authority. The study results indicated the maximum and mean current speeds of 0.6 and 0.3 m/s, respectively, with significant wave height (Hs) below 0.2 m due to island sheltering effect. Furthermore, the sediment transport predominantly occurred northwestward during the northeast monsoon and southeastward during the southwest and inter-monsoons. The predictive models for coastal flooding in 2030, 2050, and 2100 highlights the vulnerability to sea level rise, projecting up to 0.29 m by 2100 in low-lying shoreline areas. In terms of water quality assessment, the results identified generally clean marine conditions. Based on the obtained results and observations, the key issues were identified, leading to proposed management strategies for the short, medium, and long term. Uniquely, this holistic assessment not only highlights specific local conditions and vulnerabilities but also proposes targeted management strategies for different timeframes, offering valuable insights for sustainable coastal development and risk mitigation. Therefore, the study, in summary, offers crucial insights for sustainable coastal development, risk mitigation, and informed decision-making.