River Mouth Management In Malaysia– An Overview of Issues

Dredging and structural interventions have been applied for centuries in attempts to train and regulate river mouths and tidal inlet systems. The notoriously dynamic nature of river mouths and tidal inlets complicate any intervention and applied intervention schemes are frequently seen to display limited and sometimes even defective functionality. The latter is often due to lack of proper river mouth management which rely on solid assessment tools and a regard for implications of derived and external impacts. Inevitably, interventions will create an array of secondary problems (derived impacts) of which some are often unforeseen. The key parameter for success and effectiveness of interventions including adopted mitigation measures for secondary problems depends on a detailed understanding of physical conditions at the river mouth as much as on the functionality of the layout, its design and reliable risk assessments. In many cases an optimal solution is achieved by a compromise between many environmental, social and economical aspects. This paper provides an overview of the physical characteristics of river mouths and challenges and issues in river mouth management in a Malaysian context. Numerical models have been used in the past to obtain qualitative and quantitative understanding of physical conditions at river mouths which is required as part of the design of interventions, as baseline for successful management as well as to test potential intervention schemes for various design and optimization phases. Examples demonstrating the use of numerical modeling as an engineering tool for previous river mouth improvement works are highlighted to reiterate its value in river mouth engineering and hopefully serve as motivation for future usage.