Flow and Sediment Pattern Simulation at Ijok Intake, District of Larut Matang, Perak

Understanding the sedimentation processes in the river engineering and hydraulic structures are of vital importance as this can affect water supply for the agricultural lands in the command area. To understand the problem, a framework of physical and mathematical modelling were applied for investigate the flow and sediment pattern at Ijok Intake, Ijok River, Malaysia. HEC-RAS (1D modeling) and CCHE2D (2D modeling) software were used as the mathematical model where results from HEC-RAS were used as input for CCHE2D. Physical model was designed and constructed with a 1:15 undistorted scale at REDAC physical model laboratory. The comparative study using both models was performed by running simulation for ten different conditions without and with an intake structure. Based on the results, both models proved similar sedimentation pattern and sediments were accumulated in front of intake structure, hence reduce the flow capacity to convey water into the canal downstream. For simulation using intake structure, physical model is able to predict the flow and sediment transport phenomena accurately because CCHE2D model used simplification and modification to represent an intake structure. However, analyses proved that CCHE2D as two-dimensional mathematical model was able to give similar results of flow and sediment pattern as physical model. Thus, it can be concluded that combination of physical and mathematical model can give advantages in analyzing the river sedimentation near an intake structure for further design mitigation works.