Hydrodynamic modeling of Malacca Straits using EFDC

Abstract

Straits of Malacca have long been the important trade route linking the Indian Ocean to the South China Sea and Pacific Ocean, also rich with renewable and nonrenewable resources. The rapid economic development and population growth near the coastal areas exposed the coastal and marine resources to the environmental problems. The study focused to the preliminary development of hydrodynamic model of Malacca Straits by applying the Environmental Fluid Dynamics Code (EFDC) 3D public-domain modeling package. Objectives of study are to calibrate, validate and verify the hydrodynamic variables of water level, current velocity and current direction, and to simulate the hydrodynamic circulation processes of waterbodies. Water quality analysis also performed prior study to know the status of waterbodies. The model was set as coarse grid that bounded from Langkawi to Kukup, which refined for hydrodynamic calibration and verification at Batu Pahat coastal area. Optimum bottom roughness height from sensitivity analysis was applied to verify and validate the model. Statistical analysis was used to evaluate the model performance. The optimum bottom roughness heights were found at 0.001 m and 0.004 m at shallow and deeper regions respectively. The model was reasonably good in simulating water levels and current directions, respectively with correlation coefficient of 0.92 and relative RMS error of 22.92%. The wave currents circulate inward from open boundaries during flood caused collision near Port Klang coastal area. The wave currents during ebb caused maximum velocity of 1.47 m/s and maximum bed shear stress of 4.82 N/m2. Sungai Perak loads out the highest fluxes of DO, BOD, NO3, and PO4 constituents whilst Sungai Langat loads out the highest flux of NH3-N constituent during year 2009.