Seventeen major reservoirs and seven medium-sized reservoirs were either spilling or releasing water through spill gates as of Thursday, the Irrigation Department said, warning residents downstream to remain vigilant about changes in river levels.
Of the major reservoirs, 11 were spilling and spill gates had been opened at six others as of 12.30 p.m., according to the department’s Water Management Branch, the Daily Mirror reported.
The largest releases
Deduru Oya was releasing the highest volume at 4,100 cubic feet per second (cusecs), followed by Rajangana at 4,039 cusecs and Inginimitiya at 1,500 cusecs. The Nalanda, Usgala Siyabalangamuwa and Bathalagoda reservoirs were also spilling.
Among medium-sized tanks, five were spilling and gates had been opened at two more. Thuruwila was releasing 347 cusecs and Wennoruwa Wewa 75 cusecs.
Storage is high in some districts, very low in others
Total effective storage across the 74 major reservoirs the department monitors stood at 1,368,912 acre-feet — 46.1% of combined capacity. That national average conceals a wide regional split.
| District | Effective storage |
|---|---|
| Matale | 100% |
| Nuwara Eliya | 94.2% |
| Kurunegala | 91.4% |
| Matara | 82.1% |
| Hambantota | 79.9% |
| Monaragala | 36.8% |
| Vavuniya | 31.6% |
| Ampara | 19% |
Ampara recorded the lowest figure of the districts listed, at 19%. The reservoirs now spilling are concentrated in the wet and intermediate zones, while the eastern and south-eastern districts remain well below capacity — so the same report describes both a spill risk and a storage shortfall, in different parts of the country.
The warning
The department urged people living downstream of reservoirs that are spilling or releasing water to watch for changes in river levels, and to strictly follow safety instructions issued by the Irrigation Department and local authorities on spill levels and gate operations.
Related
The same rains are being felt in markets: vegetable supplies to the Katugastota Economic Centre have dropped by more than half, with traders attributing the fall to continuous heavy rain affecting upcountry cultivation.
Not reported
The filing does not name all 17 major reservoirs or all seven medium tanks, give the number of spill gates opened at each, or state how the current figures compare with previous days. It carries no Meteorology Department rainfall forecast, no Disaster Management Centre advisory, and no report of flooding or evacuations. No other verified newsroom had carried this particular daily bulletin at the time of writing.
A note on comparisons: reservoir-spill bulletins are issued frequently and read almost identically from one event to the next. Figures circulating from earlier spill events — including considerably larger releases at Deduru Oya and Rajangana — belong to different episodes and should not be compared with the volumes above.