Sedimentation Study on Upstream Reach of Selected Rivers in Pahang River Basin, Malaysia

The sedimentation study on the upstream reach of Pahang River is located in the Bentong River Basin. The detail hydrographic survey for each river in the Bentong River Basin was carried out in May 2016. Nine stations were selected to represent the sediment concentration at Bentong River, Pahang, Malaysia. Bentong River Basin is one of the river catchment in Pahang River Basin, Malaysia. Before this, Bentong River deterioration in water quality, resulting from the sedimentation problems and unsustainable development management around the river basin. This study was implemented to prove the sedimentation problem, especially the formation of Total Suspended Solid (TSS) in the Bentong River. There are two important parameters were quantified in this study such as the concentration of suspended solid (mg/L) and the river discharge (Q) values (m³/s). The method used in this study to analysis the concentration of TSS using Gravimetric Method. The result showed the sedimentation in the Bentong River was unstable and the highest of TSS up to 367.6 mg/L that is categorized under the class V which > 300 mg/L based on the National Water Quality Standard (NWQS) result showed the coefficient correlation between the observed Q and the TSS concentration in the Bentong River is significant R² = 0.919, there are strong positive relationship between TSS concentration production and the river discharge value in the Bentong River. The study found that the contributors to the high sedimentation problems resulting from the sediments generated from the unsustainable land use, which effectively trapping the bed sediments, rainfall intensity, backflow that carries out high sediments as well as sedimentation produced due to the river bank erosion.