JOHOR BARU (THE STAR/ASIA NEWS NETWORK) - Johor has assured Singapore that the Linggiu Dam, Singapore's main source of water in Malaysia, has sufficient water to supply 250 million gallons a day (mgd) to the island.

Johor State Public Works, Rural and Regional Development Committee chairman Datuk Hasni Mohamad said ongoing measures were being carried out to increase the capacity of nearby rivers or catchment areas to ensure sufficient water in the dam.

He said this was done by introducing a barrage or offsite storage, known as off-river storage (ORS), where the river waterway is enlarged to store water as well.

He said plans were carried out with the intention to increase the water storage to contain water not only in the river but to also create a catchment within the river.

"In Linggiu's case, we focus on the rivers around it like the Johor River and Linggiu River so that efforts to pump water into the dam can be done," he said on Thursday (Jan 26).

Singapore authorities have expressed concern and are keeping a close eye on the situation in Linggiu, which the island republic depends on as a water source, as it has dropped drastically over the past few years.

Singapore's Foreign Minister Dr Vivian Balakrishnan had said on Jan 9 there is a significant risk that the water level in Johor's Linggiu Reservoir could fall to zero if 2017 is a dry year.

In a written reply in Parliament, Dr Balakrishnan said the water level has dropped drastically over the past few years, from 84 per cent at the start of 2015 to the lowest recorded level of 20 per cent in October last year. The water level in Linggiu stood at 27 per cent as of Jan 1, he said.

Should the Linggiu Reservoir fail, there will be "many more occasions" when it will not be possible for Singapore's national water agency PUB to draw its entitlement of 250 mgd, he added.

The 1962 Water Agreement entitles the PUB to draw up to 250 mgd from the Johor River and in return, Johor is entitled to a daily supply of treated water of up to 2 per cent or 5 mgd of the raw water supplied to Singapore.

While Mr Hasni admitted that it was worrying when the water level in the dam hit a low recently, he assured that the situation in the state was under control.

The continuous rain over the past few days had been a silver lining as it helped increase the level in the Johor River to 5.9m, he added.