A look at the terrain would suggest that land clearing upstream in the Sungai Bertam catchment area may have aggravated erosion and surface run-off to the reservoir, which has been plagued by siltation problems (as the colour of the water in the image below would also suggest).
Mind you, this image is from 2001; so you can imagine what the situation is like today.
Blog visitor Kam Suan Pheng adds:
The Cameron Highlands (Sultan Abu Bakar) Hydroelectric Power Project at Sungai Bertam was commissioned in 1963 (Global Energy Observatory) and the Ringlet reservoir was designed with a targeted life span of 80 years. The projected life span of any reservoir is normally based on the assumption that its catchment maintains the extant condition at the time of commissioning. However poor land use management of the Bertam watershed and sediment control resulted in siltation of the reservoir by the 1990s, and the high sediment load of the river has remained unabated. A shallowed reservoir has reduced volume to retain water, hence unseasonally high discharge from heavy rainfall and high runoff will trigger rapid rise of the water surface to danger levels. This has been a disaster waiting to happen, and may not be the last one if improper land use management of the Cameron Highlands persists not only in the Bertam valley but also the upper Telom valley.
A study supported by UKM in 2010 “found that the impoundment of river as reservoir not only caused the siltation to the Ringlet reservoir itself but it also caused the siltation to the river reach after the reservoir. The disconnection of upstream and downstream had caused the interruption of upstream-downstream movement of water, sediment, nutrients and organisms by the Ringlet reservoir.”
The same study noted:
Meanwhile, according to Choy and Hamzah (2001), extensive deforestation and indiscriminate earth bulldozing in the Cameron Highlands area for agricultural and housing development has resulted in widespread soil erosion over the land surface. It leads to sedimentation of the streams and the Ringlet reservoir from which water is drawn to the power station.
This blog post by an unknown writer by the name of usoff noted in 2006:
The studies on soil erosion and sedimentation impacts affecting the Ringlet Reservoir of Hydro Cameron Highlands Hydro Electric Scheme provide vital information on the high erosion risk area within the Cameron Highlands whole catchment as well as the contribution of various land uses towards erosion and sendimentation to the lake. Agriculture activities is found out to be the main contributor to the quality of soil eroion losses within the catchment(218,160.06 t/yr), followed by mixed residential development(14,260.03 t/yr) and road project (10,642.22 t/yr). Now because of that The Ringlet Reservoir was heavily silted and estimated figure of 600,000 cu.m of sediment. To improve the original lake capacity, TNB need to carry out the major dredging project and the cost for that project is about RM160Million.
Now, who is responsible for (not) monitoring and controlling land use in the area? Would this “tragedy” have been avoidable if there had been proper control of land use and a careful periodic review of the erosion in the catchment area and the siltation at the reservoir?