BAKUN HYDROELECTRIC PLANT

Bakun HEP is committed to responsibly managing the environmental impacts of its operations by adhering to both national legal requirements and international best practices. Our approach prioritises environmental sustainability, focusing on key issues such as water quality, the health of aquatic ecosystems, sedimentation, and biodiversity conservation. By addressing these challenges, we ensure that all activities comply with rigorous regulatory frameworks while integrating globally recognised standards. Through the adoption of innovative strategies and sustainable practices, we strive to minimise our environmental footprint, protect ecosystems, and contribute to the long-term preservation of natural resources, all while meeting the energy demands of the communities we serve.

An Environmental Management Plan (EMP) for the operational stage of the Bakun Hydroelectric Plant has been developed to ensure mitigation measures are in place to manage risks and opportunities. The EMP facilitates the consistent implementation of these measures through resource allocation and clearly defined team responsibilities. It aims to manage and minimise environmental impacts while maximising positive outcomes.

Overview of the Management Plan

During the operational stage of Bakun HEP, potential environmental impacts may arise, which could lead to environmental degradation if not properly mitigated or controlled. Table 1 summarises the potential environmental impacts during this stage, outlining the project activities, environmental aspects, and associated impacts.

Project Activities/ Aspects	Environmental Issues/ Potential Impacts	Monitoring Requirements	Timing & Monitoring Frequency
Reservoir Water Quality	Deterioration of water quality in the reservoir, either influenced by or impacting the operation.	Monitoring at designated water quality locations and sampling points within the reservoir.	Monthly
		Incorporating monitoring of stratified water quality at the intake.	Half yearly
		Monitoring at designated water quality locations and sampling points at the intake during controlled releases.	As and when required during controlled releases
		Real-time water quality continuous monitoring stations (CMS) within the reservoir.	Real time
		Monitoring, interpretation, and evaluation of real-time CMS results.	Real time
		Visual inspection of the accumulation of floating debris.	Zone based
Downstream Water Quality	Deterioration of water quality in the downstream water, either influenced by or impacting the operation.	Monitoring at designated water quality locations and sampling points within the reservoir.	Monthly
		Including monitoring of stratified water quality at the intake.	Half yearly
		Monitoring at designated water quality locations and sampling points at the intake during controlled releases.	As and when required during controlled releases
		Real-time water quality continuous monitoring stations (CMS) downstream.	Real time
		Monitoring, interpretation, and evaluation of real-time CMS results.	Real time
Effluent Quality Management	Degradation of water quality due to oily effluent discharge from oil interceptors.	Monitor the condition of wastewater flow from oil interceptors through visual inspection. Check the oil scum level in the oil interceptors. Assess the condition of oil interceptors.	Monthly
Sewage Quality Management	Degradation of water quality caused by sewage discharge from the sewage treatment plant (STP).	Monitor the sewage flow condition of the sewage treatment plant (STP) through visual inspection. Check the sludge level in the septic tanks and desludge periodically. Assess the physical condition of the STP.	Monthly
Noise Management	Noise levels not to exceed 60 dB(A) during daytime and 55 dB(A) during nighttime.	Monitoring at designated boundary noise monitoring locations.	Annually
Air Quality	Release of hydrogen sulphide (H₂S) during spillage events.	Weekly water level projection monitoring.	Monthly (During normal operation)
		Yearly hydrogen sulphide (H₂S) monitoring report for operational and asset control purposes.	Weekly (During controlled release)
	Open burning.	Weekly HSSE walkabout.	Weekly
	Smoke emissions from diesel engine vehicles.	Conduct dark smoke tests for diesel engine vehicles.	Yearly
	Fuel-burning equipment, such as generator sets.	Monitoring at designated dark smoke monitoring locations.	Annually
Greenhouse Gas Emissions	Release of greenhouse gases (GHGs) with high global warming potential (GWP), such as sulphur hexafluoride (SF₆), from the powerhouse and switchyard.	Visual monitoring of SF6 tank pressure gauges for leaks or damage, and issuance of Permit-to-Work.	Bi-annually
	Smoke emissions from diesel engine vehicles	Conduct dark smoke tests for diesel engine vehicles.	Yearly
Domestic Waste Management	Improper waste management or disposal, which may result in environmental pollution.	Record the estimated quantity of waste generated for recycling and composting. Record the estimated quantity of waste disposed of at Sg. Asap Landfill.	Weekly
Scheduled Waste Management	Improper management of scheduled waste, potentially causing water or land pollution.	Weekly Workplace Inspection Bi-weekly: SEACE Monthly: ESWIS Monthly: SW Building and Emergency Response Kit Inspection	Weekly, Monthly and Quarterly
Erosion & Sediment (Upstream)	Risk of landslides.	Reservoir rim visual inspection for early detection.	Monthly
			Bi-annually
Biodiversity Management (Wildlife)	Extinction of indigenous species. Overhunting, overfishing, or overharvesting. Illegal poaching	BioMot application for reporting wildlife sightings.	Quarterly

Table 1: List of Activities and Potential Environmental Impacts during the Operation of Bakun HEP

To learn more, access the Bakun HEP Environmental Management Plan (Operation Stage) here.

Water Quality Monitoring

Bakun HEP is committed to monitoring water quality in project area for the operations of the project as water quality is crucial to supporting aquatic life thus monitoring it ensures hydro operations are not disruptive. There are total seven (7) water sampling points, with five (5) points within reservoir and two (2) points downstream of reservoir. Besides, a total of four (4) real-time water quality continuous monitoring stations (CMS), with one (1) installed at water intake and three (3) stations downstream of Bakun HEP.

Location of Water Sampling Points

Locality of CMS Stations

Floating Debris Management

Debris and logs scattered across the reservoir pose a significant risk to hydropower operations, potentially obstructing intake mechanisms and causing turbine damage. To address this issue, a debris management plan has been implemented and is executed during the operational phase of the Bakun Hydroelectric Power (HEP). This plan undergoes periodic assessment for continuous enhancement.

In the event of debris accumulation, conventional methods such as physical removal using cranes and manual labour are employed. Additionally, a log boom structure has been constructed around the Bakun HEP Power Intake and Spillway Structures. This log boom, also known as a log fence or log bag, acts as a barrier to capture and retain floating debris in the river, preventing potential damage and blockages to the turbine while ensuring optimal energy availability.

Furthermore, the Bakun HEP features a trash rack at the Power Intake structure, serving as a final measure for debris control at hydraulic structures. The floating debris captured by the trash rack is monitored daily by Dam Safety Unit, and manual clearing is conducted as needed upon the observation of a substantial debris buildup.

Reservoir Debris Control Process Flowchart

The Biodiversity Monitoring and Evaluation Plan (BMEP) at the Bakun HEP is a key initiative under the Biodiversity Management Plan (BMP). Its primary goal is to assess and monitor the environmental impacts of Bakun Dam operations, focusing on both terrestrial and aquatic fauna.

Phase 1 of the BMEP, from Q1 2024 to Q4 2025, aims to establish updated biodiversity data after 12 years of Wildlife Monitoring and Rescue (WiMoR) activities, which were conducted since 2009. The plan includes comprehensive monitoring of species within a 15 km radius of the dam, covering a variety of habitats. The BMEP also focuses on identifying emerging biodiversity issues, mapping habitats, and recommending adaptive management strategies for long-term conservation.

Initial monitoring results from December 2023 to May 2024 documented 118 bird species, 59 fish species, 25 mammal species, 22 amphibians, and 9 reptiles. Of these, 40 species are listed as Vulnerable, Endangered, Near Threatened, or Critically Endangered on the IUCN Red List, with 18 species protected under Sarawak's Wildlife Protection Ordinance. Notable species include the Rhinoceros Hornbill, Leopard Cat, and Sunda Pangolin.

Photo: Left: Installation of camera trap for mammal passive monitoring.; top right; Morphometric measurements for birds; bottom right; Plant species identification. This plan ensures that Bakun HEP operations are in line with sustainability standards, protecting local biodiversity and promoting long-term conservation.