The Irrigation Department has reported minor flooding in low-lying areas along the Gin River after water levels rose on Monday evening.
The affected low-lying areas fall within Thawalama, Hiniduma, Baddegama, Nagoda and Divithura, Hiru News reported. The department has asked residents of those areas to remain alert to the developing situation.
The Gin River rises in the Gongala hills and runs through the Galle district to the sea at Gintota. The areas named sit along its middle and lower reaches, where the valley broadens and low-lying ground floods readily when the catchment takes sustained rain.
The rise follows several days of heavy weather across the southwest, including the flooding in Colombo that has dominated the past week and the earth slip and flooding reported at Hatton.
Update: Tuesday morning
A Department of Meteorology statement carried on Tuesday morning extends the warning and attaches a named official to it. L. S. Sooriyabandara, Director of the Hydrology Unit of the Irrigation Department, said a minor flood situation could occur within the next few hours in the downstream areas of the Gin River, specifically in the Nagoda, Baddegama and Welivitiya-Divithura divisional secretariat divisions, NewsFirst reported.
That list is narrower than Monday’s. The three divisions named on Tuesday are downstream areas; Thawalama and Hiniduma, which appeared in Monday’s Hiru account, are not named in the Tuesday filing. Neither source explains the change, and it should not be read as those areas having been cleared.
The same statement supplies the catchment rainfall figures missing from Monday’s filing. As of 5.30 a.m. on Tuesday the highest rainfall in the country was 162.5mm at Deniyaya, with 139mm at Udugama and 115mm at Dehiowita (Deraniyagala). Deniyaya and Udugama both sit in the Gin River’s upper catchment, which accounts for the rise downstream. Water levels have also risen in the Kalu and Kelani rivers and the Attanagalu Oya, and the department expects more than 100mm of further rain in parts of four provinces during Tuesday.
Not reported
The filings do not give the river’s gauge height at any station, do not state which alert threshold has been crossed, if any, and do not characterise the flooding beyond “minor.” They give no number of affected households or evacuations and name no road closures. They do not say how long the department expects levels to stay elevated. The rainfall figures and the named official, flagged as missing when this article was first published, were supplied by Tuesday’s filing and are set out above.
A note on sourcing
This report was single-source on publication and has since been corroborated by a second verified newsroom. Ada Derana has carried the Gin Ganga advisory, but that site has returned HTTP 403 to this desk on every route tried for more than a week and cannot be fetched or date-verified, so it cannot be cited. The Daily Mirror rail was checked directly and carries nothing on this particular rise.
Readers should also be aware that “minor flood warning for low-lying areas of the Gin River” is close to a standing seasonal headline. Searches return several distinct Gin Ganga advisories — including ones tied to Cyclone Arnab and a separate late-October episode — with near-identical wording and overlapping place lists. Figures circulating against that phrase, such as a 4.10-metre reading at Thawalama against a 4.00-metre alert level, belong to earlier advisories and are not stated in Monday’s filing. They are deliberately excluded here. The detail that fixes this report in time is the Monday-evening rise and the five areas named above.