Author(s): Anizawati Ahmad, Wan Hanna Melini Wan Mohtar, Nor Aslinda Awang
Linked Author(s): Anizawati Ahmad
Keywords: Sea level rise, hydrodynamic, bed load changes
Abstract: The complexity of estuarine hydrodynamics arises due to the continuous interaction between freshwater and saltwater. The hydrodynamic process is influenced by marine factors such as tides, waves, salt water intrusion, river discharge, sediment type and shape of the mouth. This research attempts to investigate the bed changes at Kuala Pahang due to sea level rise-induced hydrodynamic reactions. The study area experiences dominant mixed semidiurnal tides and is projected to hit with sea level rising up to 0. 034, 0. 144 and 0. 307 m in 2020, 2060 and 2100, respectively. The rate of sea level rising is the third highest, at the East Coast of Malaysia after Kelantan and Terengganu. The increase in sea level caused changes in water depth, bathymetry and hydrodynamic pattern. The increase in flow velocity promotes erosion and the reduction in flow velocity lead to sediment deposition. MIKE 21 software is used in the numerical modeling to analyze the hydrodynamic processes while Sand Transport (ST) module is used to study the sediment transport. The sea level rise factor is combined to obtain the changes of the study area. The study is limited to the southwest monsoon. Modeling work is also conducted for a temporal scale of 14 days, taking into account a full tidal cycle. The historical analysis of bathymetry changes is done by comparing the bathymetry data in 1952 and 2014 using ArcGIS software. The analysis showed that the bathymetry has changed between -0. 08 to +2. 9856 m in the last 62 years. Hydrodynamic modeling results indicated that the flow velocity changed between -0. 01 - +0. 18 m/s on average, and the maximum values is between -0. 06 - +0. 2 m/s. Sediment transport modeling shows the average rate of bed level change which is between 0. 2 to 0. 6 m/dy and average bed load changes is between 0. 0002 - 0. 0008 m3/s /m. Analysis has shown that the southern part of estuaries, meanders of rivers and near island experienced decrease in flow velocity which indicated sedimentation
Year: 2017