FOUR days of heavy rain and the release of water from the Bakun hydroelectric dam threaten to flood low lying areas along the banks of upper Sungai Rajang, said the state Disaster Management Committee last night.

The area under most threat is Belaga district, and the town that bears the name is the last town on the country’s longest river.

Belaga, whose inhabitants are mainly from the Orang Ulu ethnic community, is about 120km from the town of Kapit.

The state Disaster Management Committee said the water level of the river rose rapidly on Monday and yesterday when the dam water was released “for safety reasons” during heavy rains.

The overflowing Rajang inundated villages and settlements along its banks.

Among the settlements most threatened by the swift rise of the river is the settlement of Punan Ba.

The committee reported while the water level rose swiftly yesterday morning, the water did not enter any home but did temporarily cut the Belaga-Bakun road when the bridge at Long Mekero became impassable to all traffic.

It was passable late yesterday evening.

The 2,400-megawatt (MW) Bakun dam, about 60km from Belaga on Sungai Balui  – a tributary of the Rajang – is one of the state’s largest hydroelectric dams.

With a crest elevation of 235m above sea level, the dam’s maximum flood level is 232m.

Its 695 sq km reservoir area can hold 43,800 million cubic meters of water.