Bakun Reservoir to Commence Controlled Release 9 March

8 MARCH 2020

Sarawak Energy is commencing its seasonal controlled release of water from the Bakun reservoir from 9 March 2020 due to the recent heavy rainfall in the area.

In addition to generating electricity, hydropower dams such as Bakun Hydroelectric Plant (HEP) mitigate the impact of heavy rainfall on downstream flow by holding back large volumes of water in its reservoir.

When the reservoir level exceeds a certain point, water is released through a spillway specially designed for this purpose. This is a standard practice undertaken by hydropower operators worldwide.

This controlled procedure ensures water is released at regulated volumes through the gated spillway over a duration of time, to achieve the required level in the reservoir, and to minimise the impact to the downstream regions.

Nevertheless, over the release period, downstream towns are expected to experience minimal rise in river levels. Hydropower dams are capable of mitigating impacts from heavy rainfalls within the upstream catchment, but other factors such as high sea tides, heavy rainfall downstream into catchments and tributaries of the Rejang can still result in floods, unrelated to the scheduled release.

The release of water, scheduled for an estimated period of three weeks, will be kept as low as possible, and will cease once the water level at the reservoir normalises.

The released water is estimated to flow past Kapit town about one day after the release and Sibu town after three days*. The rise in river level and intensity of flowing water will reduce as the distance increases.

On top of flood mitigation, the dam also holds river debris within the catchment, making downstream navigation much safer.

*Note: Amended from Kapit (two days) and Sibu (four days) to reflect current information.