The dam’s water level, which is at around 35%, has depleted due to dry weather and the increased use to make up for a shortfall in areas that had water cuts recently.

PBAPP, which previously touted the 20% reserve as an emergency buffer in case the dam’s water level reduces further, today described the reserve as “dead storage”.

“It cannot be used due to heavy siltation. This is because the Air Itam dam has been in service for 62 years,” PBAPP CEO K Pathmanathan said in a statement.

“We would like to clarify that the dam’s effective capacity is 34.6%. This is the capacity that matters for water supply operations,” he said.

The dam, which serves 170,000 residents in Air Itam, Paya Terubong, and parts of Green Lane on the island, currently has about 30 days’ worth of water left.

Despite the setback, Pathmanathan said the dam’s water level could improve to 50% by the end of April as drawdown from the dam would be reduced.

He said PBAPP plans to pump 33 million litres a day (MLD) of water into Air Itam dam through water from Butterworth. This will involve filling the Padang Brown pumping station, which then connects to the Air Itam water treatment plant.

The dam was at 83% capacity on Dec 1 before a major pipe rupture in Butterworth. Following the emergency response to the rupture, the Air Itam dam’s water production was doubled from 22 MLD to 40 MLD, resulting in a drop to 67% on Jan 6.