• Largest Jaffna scheme estimated at $ 220 m  

The National Water Supply and Drainage Board (NWSDB) is proceeding with three seawater desalination projects in the Jaffna Peninsula to address acute freshwater shortages in areas with scarce natural surface water resources. 

The move comes as dry weather conditions continue to affect 35,169 families, comprising 115,586 people, across seven districts.

The three sea water purification projects are currently underway under the NWSDB, with the Jaffna city scheme, the largest of the three, estimated to cost $ 220 million and funded through a loan from the Asian Development Bank (ADB). 

NWSDB Chairman Chandana Bandara told The Sunday Morning that the remaining two projects, focusing on islands in the Northern Province and smaller in scale, were estimated to cost between $ 20 million and $ 50 million. 

Explaining the reason behind turning to seawater desalination to supply water to the Jaffna Peninsula, Bandara said that natural freshwater sources were exceptionally scarce in Jaffna, where lagoon water and shallow well supplies suffered from high salinity. To address this, the NWSDB is using Reverse Osmosis (RO) technology in order to remove salinity and treat seawater for public distribution.

His remarks followed the disclosure by Minister of Water Supply Susil Ranasinghe in Parliament on Thursday (10) on the status of the three seawater projects.

A central RO desalination plant with a processing capacity of 24,000 cubic metres per day has been installed to supply the city of Jaffna.

“The use of RO technology is not new to Sri Lanka, as it has previously been used on a small scale. However, this is the first time we are using it on such a large scale,” Bandara said.

“We have currently provided around 100,000 connections to cover a significant portion of the city’s population and we are expanding further,” he noted, adding that smaller desalination units previously installed across the northern islands were also being upgraded and reactivated.

Alongside the desalination drive, the NWSDB has launched a groundwater exploration project to prepare for severe drought conditions forecast by meteorologists. Bandara explained that prolonged dry weather primarily depleted surface water levels in rivers and reservoirs, making deep underground water reserves essential for maintaining supplies.

The deep groundwater initiative is already operational in the North Western and Southern Provinces, with expansion underway across the Eastern, Central, Sabaragamuwa, Uva, and North Central Provinces, targeting areas including Anuradhapura, Polonnaruwa, and Puttalam. The project involves constructing new deep tube wells as well as cleaning and restoring existing abandoned wells.

Meanwhile, addressing Parliament on the national water scarcity and the Government’s countermeasures, Minister Ranasinghe said that water bowsers had been deployed to meet urgent community needs. He added that the Government had increased the official daily drinking water allocation from six litres to 15 litres per person.

The Minister said that groundwater sources and certain inland reservoirs, such as Unnichchai Wewa in Batticaloa and local supply systems in Monaragala, were experiencing declining water levels and supply constraints. However, seawater purification facilities and key western river basins continue to operate without disruption.

The NWSDB purifies approximately three million cubic metres of water daily, drawing on a combination of groundwater, reservoirs, rivers, and seawater desalination.

To safeguard communities against the ongoing impacts of El Niño and dry conditions expected to extend into early 2027, the Government is implementing medium- and long-term measures, including the restoration of abandoned tube wells, with 57 already rehabilitated in Monaragala, and the strengthening of groundwater infrastructure.

Local disaster management mechanisms, led by divisional secretaries in coordination with local authorities, armed forces, and community organisations, are overseeing bowser operations, fuel subsidies, and localised relief efforts across the affected districts.

According to figures presented by Minister Ranasinghe, groundwater is drawn from 59 sources across the country, providing between 7,000 and 10,000 cubic metres daily. These sources are currently affected to some extent by the dry weather.

Another 59 reservoir sources supply 1.2 million cubic metres daily. Major reservoirs under the Department of Irrigation are at 34% capacity, but with agricultural water releases concluded for the season, the available water is expected to be sufficient to maintain drinking water supplies until rains arrive at the end of September.

Reservoirs under the Mahaweli Authority remain above 50% capacity, with no supply issues expected. At the Senanayake Samudraya in Ampara, water levels have declined, although the suspension of agricultural releases is expected to maintain adequate capacity until the anticipated late-September rains.

Rivers and streams provide approximately 2.2 million cubic metres daily. In the Western Province, recent rainfall in the Kalu Ganga and Kelani Ganga basins has maintained water levels without any significant decline, securing supplies for 1.3 million consumers through late September.

Seawater is drawn and purified through the three main desalination projects, which the Minister said were currently operating without issues.

In Batticaloa, falling water levels at Unnichchai Wewa have forced authorities to reduce water supply to 75,000 families from 24 hours to 20 hours a day. Existing capacity is expected to remain manageable until the late-September rains, while three alternative wells are being prepared in case the main supply has to be further restricted.

In Monaragala, NWSDB supplies have been disrupted in Bibile, Medagama, Madulla, and Monaragala town.

Islandwide, of the 5,464 community water schemes, 1,897 are either under threat or have already dried up. These include small wells, tube wells, and local streams that typically supply communities of between 100 and 150 families.

While the current dry conditions are expected to ease with rains anticipated in late September and during October, November, and December, weather forecasts point to an unusually severe dry spell in February, March, and April 2027, driven by El Niño.