Controlled Release Of Water From Bakun Hep Reservoir To Commence From 13 July To 3 August 2024

Predictive technology based on weather and inflow forecasts provides a 6-month lookahead

10 JULY 2024

Sarawak Energy will commence its seasonal controlled release of water from the reservoir of the 2,520MW Bakun Hydroelectric Plant (HEP) from 13 July to 3 August 2024 (3 weeks). In compliance with the Sarawak Rivers Board's requirements, approval is secured from the authority prior to the controlled release. Additionally, the relevant communities are notified through public notices and social media at least two days ahead of the scheduled release.

During this period, Sarawak Energy will release water in regulated volumes through the gated spillways, utilising a dynamic water dispatch management system introduced in 2020.

The system integrates data on weather and inflow forecasts to manage the reservoir levels by incorporating predictive weather patterns. This provides more accurate inflow forecasts and projected reservoir levels up to six months or more. Inflows refer to water that flows into the reservoir area from various sources, primarily streams, rivers, and other surface water bodies.

The system is also utilised by the Batang Ai and Murum HEPs to better manage the relationship between weather, water flows and water release requirements. In addition to enabling Sarawak Energy to operate its hydroelectric plants more efficiently, this system facilitates better planning and scheduling of controlled releases.

Seasonal release of water is part of the hydropower operator's annual standard practice to manage and regulate water levels upstream and downstream of the facility. This results in improved water level management both upstream and downstream, supporting river navigation during the dry seasons where relevant and flood mitigation during rainy periods. Since the commissioning of Bakun HEP, the severity of downstream flooding for the Rajang River has been minimised.

All hydropower facilities operated by Sarawak Energy are guided by the International Commission on Large Dams (ICOLD) and the Hydropower Sustainability Standard (HSS).

The reservoir of the Bakun HEP.

Sarawak Energy staff taking real-time data of reservoir water levels.