Groundwater levels in parts of the Jaffna Peninsula and Kalpitiya have fallen by around 70 to 80 per cent, the Water Resources Board says — but measured against their seasonal maximum, not against total reserves.
That distinction is the substance of the board’s statement. Assistant General Manager for Research and Development Ruwan Rajapaksha told the Daily Mirror that the percentage refers to the drop from the peak level reached earlier in the season, and that such fluctuations do not in themselves mean the country’s groundwater is being depleted.
“If we look at the climatic behaviour from December through March and April and then up to August, there is generally a decrease in groundwater levels around August,” he said. Levels fall through the drier months, with the reduction most pronounced around August in areas that receive less rainfall.
Kalpitiya and the Jaffna Peninsula are showing the largest reductions, driven mainly by lower rainfall.
Where extraction changes the picture
Rajapaksha’s caution was directed at what happens on top of the seasonal cycle. Extraction can push levels further down where water use is high, he said, and the volume that can safely be taken should be set by scientific assessment rather than demand.
He warned that excessive and unregulated extraction could eventually cause wider environmental and water-quality problems. Jaffna is the particular concern, because groundwater is the peninsula’s main source of water and has no ready substitute.
That sits alongside a shift in the opposite direction elsewhere. The National Water Supply and Drainage Board is drilling about 60 tube wells in Monaragala, with more planned for Batticaloa, precisely because surface reservoirs have fallen to 34.7 per cent. One agency is turning to groundwater to cover a drinking-water shortfall while another warns about the limits of drawing on it — in different districts, but under the same dry spell.
How the levels are measured
The board monitors groundwater through a network of about 1,600 observation points, of which roughly 190 are equipped for real-time monitoring. Manual measurements are taken between March and April and again from June to September.
Because those readings are periodic, Rajapaksha said, they can miss short-term changes. The board has begun a real-time monitoring pilot at Point Pedro in Jaffna, the Puttalam region, Mannar, Kumbukkan Oya and Maduru Oya.
No other verified Sri Lankan newsroom had reported the board’s assessment as of Saturday evening.
