Reservoir sedimentation under land use and climate variation: case study of Ringlet, Cameron Highlands

Abstract

: Ringlet Reservoir in Cameron Highlands has suffered from severe sedimentation due to active agriculture and urbanisation in the catchment, leading to flooding in Bertam Valley in October 2013 and severe storage reduction affecting hydropower operation. This research focuses on the prediction of long-term sediment inflow in Ringlet reservoir under land use and climate variation based on the SWAT sediment yield model. From this study, the sediment yield rate for the catchment ranges from

33.1 to 56.9 ton/ha/year, with Lower Bertam, Habu, and Ringlet being the most sediment-prone areas. These rates are higher than in any other areas in Malaysia and it also shows that sediment yield was greatly influenced by land use, slope, catchment area, and runoff. Under land use change 1997, 2006, 2010, 2015 and 2030 modelled in SWAT, the average annual inflow into Ringlet Reservoir is averaged at 8.02 m3/s, with a range from 5.54 m3/s to 10.35 m3/s while annual sediment load into Ringlet Reservoir is averaged at 342,614 m3/year with projected increase up to 461,886 m3/year by 2025. This is equivalent to 1.2% of annual storage loss. This puts Ringlet Reservoir at high risk in terms of sedimentation rate. Integrated sediment management is needed, focusing on preventive and corrective measures to ensure its sustainable operation.