Validation of MIKE 11 Model Simulated Data for Biochemical and Chemical Oxygen Demands Transport

The aim of the study was to model the discharge, biochemical and
chemical oxygen demands (BOD and COD) loads in each cross section of Bertam River in Cameron
Highlands, Malaysia. Cameron Highlands form the headwater catchment for two major rivers of the
lowlands; Pahang River and Perak River. On the other hand, Cameron Highlands is undergoing rapid
development as a popular tourist destination and an area exploited for growing of temperature
vegetables, fruits and flowers. It is also a mountainous area subjected to torrential tropical showers.
The condition of Bertam River as one of the main rivers in Cameron Highlands has degraded over the
years in terms of water pollution and river environment. Approach: Therefore, MIKE 11 a onedimensional
hydrodynamic simulation program was utilized to model stream flow transport and water
quality processing in the river system. The model was used to generate the river outflow and simulate
BOD and COD concentrations in each cross section of Bertam River. Hydrodynamic Module (HD)
which uses an implicit, finite difference solver was applied to calculate water level and flow for the
river. Next, Rainfall-Runoff Module (RR) which is include unit hydrograph method and lumped
conceptual continuous hydrological model was used to combine the meteorological data of the study
area to MIKE 11 simulation system. Finally, Advection-Dispersion Module (AD) was used for
transported BOD and COD concentrations calculation. Results: Water quality results show the BOD5
varies from 1-2 mg L-1 during pre-monsoon and from 4-10 mg L-1 during post-monsoon. The COD
between 39-49 mg L-1 was observed during High Water Flow (HWF). Much lower concentration was
detected during Average Water Flow (AWF) which was between 10-14 mg L-1. The comparative
analysis between measured and simulated data showed that MIKE 11 is able to predict sufficiently
accurate BOD and COD loads at the catchment outlet especially during AWF. Conclusion: Due to
higher discharge during HWF some differences between measured and predicted values were
observed. Therefore, it is suggested that for better agreement at higher discharges the hydraulic model
simulation to be conducted using more measured flow data and by application of more precise
differential equation such as RKQC and RK4.