PUTRAJAYA, Oct 23 — Malaysians could face more interruptions to their piped water supply due to the ageing infrastructure of many of its dams, with over one-third of these structures being more than 50 years old.

National Water Services Commission (SPAN) chairman Charles Santiago said 16 out of 55 dams in peninsular Malaysia that are used for water consumption are more than 50 years old and the authorities are uncertain about the usable capacity should there be a prolonged dry spell.

Another seven dams are in critical condition and their structural integrity is in need of urgent attention, he added.

"Many of our dams are in critical condition. Their structural integrity must be evaluated as they are old, more than 50 years old some of them,” he said in a press conference here today.

He said that the water level readings at some dams might indicate 20 million litres per day (mld), but actually, only 15 mld is usable due to "dead storage at the bottom”.

"We need to clean this and sometimes we don’t. And because of climate change, we need to be prepared for the next 20 to 30 years by taking steps now to improve our water security,” he said.

He said that many of the dams have not been properly maintained or had their water levels audited.

As such, it was difficult for the authorities to know how much silt has accumulated at the bottom of the dams, causing "dead storage”.

"When we pump the water out we see only about 15 out of 20 mld that’s usable due to poor maintenance.

"We hope to raise some awareness today and highlight this issue so the relevant agencies and government can take further action,” Charles said.

He said the situation is dire as no one actually knows how much water is usable in a crisis, adding that the weather has become increasingly unpredictable.

According to Charles, the seven dams that are in critical condition are the Pedu and Muda in Kedah, Mengkuang in Penang, Durian Tunggal, Asahan and Jus in Melaka and Linggiu in Johor.

He also said that SPAN had carried out a survey of rivers in the country and found their water levels have dropped in recent years, attributing it to the changing climate.

He said Sungai Muda, the main raw water resource for Kedah and Penang, had dropped by 7 per cent.

He said the phenomena has been observed happening in all rivers in Malaysia and is set to continue.

Charles said that to move forward, Malaysia requires more off river storage (ORS) facilities like the ones in Rasau, Selangor.

The facility was repurposed from an abandoned tin mine and is being used to collect and supply water into the water treatment plants.

Charles said this method is being used in other countries as well and is the best way forward.

"We have ORS and also off-river storage facility in Malaysia and we need more. Projects like the one in Rasau have also been used in Canada where they decommissioned old gold mines and used it as water catchments,” he said.

"This is a big issue and I urge everyone including businesses that use lots of water to be prepared and prudent with their water consumption as we work to preserve our water security,” he added.