Determination of Sediment Transport Rate at Dungun River, Terengganu

Excessive erosion and sedimentation have become the greatest factors that influence the effect on river morphology in Malaysia. Recently, the sand mining activities from rivers in the area of Dungun, Terengganu State, have increased alarmingly due to commercial demand in the construction market. The excessive river sand mining may lead to anthropogenic stresses that render water quality degradation, alteration in flow, and sediment regimes. The main objective of this paper is to observe the longitudinal cumulative mass change along the Dungun River system. The hydrologic engineering center’s-river analysis system (HEC-RAS) version 6.0 was used to simulate quasi-unsteady sediment transport analysis. The HEC-RAS model is able to simulate riverbed change as well as the area that susceptible toward either erosion or deposition. After a series of simulation, it was found that the net cumulative of erosion occurred at the upstream with an estimated sediment loss of 130,000 tons/year while the net deposition occurred at the downstream area with an estimated sediment load of 300,000 tons/year. This finding is crucial for mitigation purpose which might help navigation activities at the downstream of Dungun River.