Flood warning sirens at the Batang Ai Hydroelectric Plant will sound several times today, Friday 2 October 2026, between 8.30am and 4.30pm. It is a scheduled test and not an emergency, according to a notice from Sarawak Energy. The utility says each activation should last about one to two minutes. It is asking people living near the plant not to be alarmed when they hear them.

What residents will hear, and when

The notice sets out the arrangements:

  • Date and hours: Friday 2 October 2026, 8.30am to 4.30pm.
  • Duration: roughly one to two minutes for each activation.
  • Frequency: several activations. Sarawak Energy says the timing and number of activations may change depending on how the testing progresses, so there is no fixed schedule.
  • Enquiries: Sarawak Energy's 24-hour Customer Care Centre on 1-300-88-3111, or the company's official channels for updates.

The notice describes the work as scheduled testing and maintenance of the plant's Flood Warning System (FWS). It is also preparation for a station emergency preparedness drill, which the notice calls upcoming but does not date. Sarawak Energy says regular testing of the system forms part of its continuing dam safety and emergency preparedness measures. The notice was issued in English, Malay and Iban.

How far the sirens carry

Today's notice does not give the sirens' range. The last test Sarawak Energy announced for the area, in November 2023, did. It covered the flood warning stations in Lubok Antu, and the company told communities that the warning tones could be heard up to 3km from each station. That test followed the same pattern as today's: one to two minutes per activation, with no fixed timing or count, running from 10am to 5pm on 15 November 2023. Sarawak Energy described it as routine and said it was aligning its emergency response programme with international standards.

What the dam holds back

Batang Ai was Sarawak's first hydroelectric plant. Sarawak Energy's power generation page gives these details:

  • It began operating in 1985.
  • Its dam is 85m high and 649m wide, and it impounds a reservoir of about 90 square kilometres.
  • Power reaches Kuching over a purpose-built 275kV transmission line.
  • The catchment area covers 120,000 hectares.

The same page gives two capacity figures. One section lists the plant at 94MW. Another says it delivers up to 108MW. The page does not explain the difference.

The plant has four generating units, all of which were back in service by 22 May 2024 after the first stage of an automation upgrade. Sarawak Energy said the upgrade was meant to improve how the plant manages power generation and water resources. The company warned at the time that the shutdowns could lower water levels on the rivers downstream around Lubok Antu. The reservoir sits in the Sri Aman division, next to Batang Ai National Park.

Why a dam needs a flood warning system

Warning systems on hydro dams exist mainly to protect the people living downstream. At a dam safety conference in March 2023, Sarawak Energy's group chief executive said the company's Dam Safety Programme aims to mitigate risks to communities both upstream and downstream. He said it follows international best practice. At the same conference, a Sarawak Energy engineer won a best technical paper award for a study estimating evacuation times for a hypothetical total dam breach at Batang Ai. That was a planning exercise, not an assessment that a breach is expected. It shows the evacuation case the company has studied for this dam.

The drills that test the response plan

The sirens are one part of a wider emergency arrangement that has been rehearsed with government agencies:

  1. 2019 workshop. In November 2019, Sarawak Energy held a two-day workshop with bodies under Sarawak's State and District Disaster Management Committee, attended by departments from Kuching and Sri Aman. Its purpose was to formalise who does what at Batang Ai in an emergency, with the results to be validated in a tabletop exercise.
  2. 2023 full-scale drill. From 14 to 16 March 2023, the National Security Council (MKN) Sarawak ran Ex Red Tilapia 2023 at the plant, with more than 500 participants from some 35 government departments and agencies. It was Sarawak Energy's first full-scale physical simulation with MKN. The exercise included evacuating plant workers and nearby residents.

During that drill, Sarawak Energy said it holds an Emergency Response Plan for Batang Ai and was using the exercise to test the plan's coordination with government bodies. The release also records that the government classifies Batang Ai as a National Key Point 2 facility. Today's siren test is described as preparation for the next such drill. Sarawak Energy has not yet announced when that drill will be held.

Sources