The Cameron Highlands region in west central Malaysia was developed as a ‘hill station’ or high elevation holiday resort/retreat in the 1930’s by colonial officials, following the establishment of an agricultural research station there in 1925. Apart from being a retreat for bureaucrats from the heat of summer in the lowlands, the area was found to be suitable for growing tea and fruit.
Following independence in 1957, the Lake Ringlet reservoir (part of the Sultan Abu Bakar Dam) on the Sundai (River) Bertam was commissioned in 1963 as part of the 262MW Cameron Highlands-Batang Padang Hydro-electric Scheme. The Dam is 39.6m high and impounds water from a 183 square km catchment in the highlands.
The dam, with its four spillways, is one of the oldest in the country. Water from the dam is normally channeled via a tunnel to an underground power station further downstream. In order to protect the river banks that hold the dam wall in place from rapid erosion caused by overtopping of the water, and potential catastrophic failure of the dam, the four spillway doors are designed to open automatically when the water level rises beyond the safety limit. Since this would release a large amount of water into the river below, it is standard operating procedure to open one gate at a time as the water level rises, after sounding warning sirens to alert residents in the valley below the wall. Sequential opening of spillway doors reduces the amount of water being released from the reservoir, in order to reduce the risk of flooding.
In October 2013, flash-flooding in the catchment of the Ringlet reservoir coupled with existing siltation resulted in a rapid rise in the water level, necessitating such a step. Unfortunately, even the controlled release of water resulted in the flooding of 100 houses in the village Kg Bertam Valley on the Sundai Bertam below the dam, and led to the death of four people.
The release of water was implemented according to standard operating procedure, so why did it cause such calamity?
In reality there are a number of contributing factors. These include a more rapid rise in water level than usual, owing to deforestation, increasingly intensive agricultural activities and in some cases poorly managed agricultural practices in the dam’s catchment area. This is coupled with poor land use practices and the encroachment of urban development into the flood plain below the dam.
Siltation and increased run–off has been an ongoing concern at Ringlet for some years. TNB Cameron Highlands Power Stations General Manager Mustafa Hashim has stated that the Ringlet reservoir’s water holding capacity has greatly decreased due to the high volume of rubbish, sand and silt sediment on the lake floor, and that siltation over the years from land clearing in the Cameron Highlands has resulted in the need for a near-continuous de-silting programme. He stated that TNB, the electricity supply authority, had spent some RM80 million (US$25m) worth on dredging sediment material, an operation carried out once every five years. It also spent another RM20 million (US$6.25m) on annual maintenance works. Mustafa, who has been working at the Cameron Highlands since 2011, said the water level in the dam had also risen rapidly due to the presence of the white plastic sheets seen in farms all over Cameron Highlands, adding that these caused the rainwater to flow swiftly into the rivers without first being filtered by the ground.
A study undertaken in 2006 noted that de-silting measures were able to lessen but not stop sediment accumulation, and that Ringlet Reservoir had already lost nearly 53% of its storage capacity to siltation. This substantially reduced the capability of the reservoir to regulate incoming high flow, leading in monsoon season to more frequent spillage and flooding of the downstream Kg Bertam Valley.
Regarding the flooding in October 2013, TNB president and chief executive officer Datuk Seri Azman Mohd said in a statement that the water level of Lake Ringlet had risen at a rate of 0.59m per hour between late Tuesday (Oct 22) and early Wednesday (Oct 23), which was 13 times more than the normal monsoon rain condition.
He added: “The unusually intense downpours on Oct 22 and 23 had brought huge volumes of water to the lake, together with solid waste, debris and siltation from massive land clearing and farming activities upstream”.
As far back as mid-2012, the group Regional Environmental Awareness Cameron Highlands (REACH) began raising the alarm about deforestation in the area. In an October 2012 report, REACH president R. Ramakrishnan said he had submitted a letter in August 2012 to Pahang Mentri Besar (Chief Minister) Datuk Seri Adnan Yaakob, complaining about clearing of land in Pahang. He believed that most of the clearings were illegal. Even if permits had been issued in some cases, he added, the conditions were not being adhered to in accordance with the Land Conservation Act 1960.
Rampant tree felling seems to have been going on for several months before this despite authorities seizing heavy equipment including backhoes and excavators, with the culprits working at night deep in the forests. In addition, encroachment of human activity into the river reserve has added to both the increase in run-off and siltation, increasing the speed of water level rise in the reservoir and thus contributing to the damage suffered below the dam wall.
The river reserve is a strip of land on both river banks gazetted in terms of Section 62 of the National Land Code. This land acts as a buffer between the river and the surrounding land, aimed at protection of the river from undesirable activities that may affect its functioning. The breadth of the river reserve depends on the width of the river at any point. No structure, permanent or otherwise, or farming activity, is permitted to take place within the river reserve, in order to ensure people’s safety from erosion and flooding.
However, it was found that there were human settlements and activities along more than 6 km of the 25km of land adjacent to the Bertam River above the Ringlet Reservoir. In addition to deforestation which increases the velocity and erosive power of rainwater run-off, covering of the soil with buildings as well as widespread large-scale use of plastic ‘tunnels’ for agriculture has decreased absorption rate of rainwater into the soil, leading to increased runoff and higher volumes of both silt and water entering the river courses.
A similar phenomenon is occurring below the dam, where agriculture and urban development have encroached up to the river edge in many places. A glance at photos of Kg Bertam Valley or an aerial view of the village on googlemaps shows how the course of the river through the buildings and agricultural tunnels can only be traced with difficulty owing to the density of development along its banks. Ramakrishnan claims that many of the farms that had been flooded were illegal as they had been established within the river reserve despite the existence of TNB signboards warning farmers against doing so. District Officer Datuk Ahmad Daud noted that some farmers had been granted Temporary Occupation Licences, which expire at the end of the year.
According to Daud, authorities have attempted for the last five years to persuade farmers and villagers to relocate away from the river reserve, without success. He added that local authorities had organised educational programmes and events to clean up the rivers but the response from farmers had been poor. Earnings of about RM2billion (US$780m) in exports of fruit and vegetables tended to cause farmers to go beyond their boundaries, resulting in “reckless farming”, Natural Resources and Environment Minister Datuk Seri G Palanivel is reported as saying after the floods.
In response to the flooding, it has been reported that the Drainage and Irrigation Department (DID) is planning to use the RM40m allocation from the Prime Minister, contained in the 2014 budget tabled on October 25, to build concrete embankments along a three kilometre stretch of the Bertam River, in order to ensure better water flow. Pahang DID director Datuk Zulkefli Hassan said that he hoped work on the walls would start by the middle of 2014.
Demolition of illegal structures in the river reserve, for a distance of 20m on either side, in order to make way for deepening and widening of the river, was commenced by the DID, assisted by the District Office on 7 November 2013, just two weeks after the flooding. District Officer Datuk Ahmad Daud said a site in Ringlet had been identified for the relocation of affected residents.
From analysis of the causes of the flooding, it appears that more is required than simply canalizing the river, and that a more integrated approach to catchment management and land use management is required.
It is ironic that this tragedy occurred only a week before the closing date for comments on amendments to the Local Plan of Cameron Highlands 2003-2015 (Rancangan Tempatan Daerah Cameron Highlands 2003-2015), and a few months after the announcement in June 2013 that the Natural Resources and Environment Ministry “is studying the possibility of preparing an environmental blueprint for Cameron Highlands as a long-term initiative to combat the myriad of issues there”, including “water pollution resulting from illegal land clearing, highland farming without erosion and siltation control efforts, as well as breaching of permanent forest reserves and river reserves”.
Clearly the time for action has arrived.
Sources: IEA Hydro; The Star Malaysia; Asia One; NST; Cheammay Choo