Application of Constant Rate of Supply Model for the Determination of Sediment Accumulation Rates and Chronology of Bukit Merah Reservoir Perak, Malaysia

The Constant Rate of Supply (CRS) model is used to measure the continuous influx of unsupported 210Pb into the sediment, allowing for the assessment of changes in the rate of sediment accumulation due to anthropogenic impacts over time. Thus, the CRS model was used to analyze a 25 cm bottom sediment core extracted from Bukit Merah Reservoir. Results revealed a high sedimentation rate in the reservoir, which ranged from 0.14 to 0.37 gcm-2 yr-1, with a mean sedimentation rate of 0.31 cm yr-1. The presence of 137Cs was not observed in the core, while the activity of 241Am was detected in two isolated samples but was insufficient for use as a marker. The constant rate of 210Pb supply (CRS) model dated the oldest sediments (22.5-24.5 cm) to AD 1985 ± 34 years of human influences. Overall, the sedimentation rate in the reservoir experienced a rapid increase from the 1980s to the 2000s and fluctuated to the top of the core indicating continuous anthropogenic impacts on the reservoir. The study identified continuous increases in agricultural activities, expansion in the tourism industry, population growth, and changes in land use, as the main cause of heightened sedimentation and sediment particles delivery into the reservoir. Therefore, urgent measures are needed to address the current siltation state of the reservoir.