The spill gates of the Kotmale Gamini Dissanayake Reservoir were opened at 11.30 a.m. on Wednesday, releasing 150 cubic metres of water a second into the Kotmale Oya, and residents downstream of the dam have been told to stay alert.
The reservoir stood at 701.3 metres above mean sea level at 10.15 a.m. — about 1.7 metres below its spill level — when the decision was taken, the Daily Mirror reported. The gates were opened because of the prevailing wet weather and forecasts of further rain over the reservoir’s catchment, to draw the level down and reduce the risk downstream.
That is the detail worth holding onto: this was a pre-emptive release, not a reservoir overtopping. The dam had head room and the operators spent it deliberately ahead of more rain.
Who warned whom
The Daily Mirror attributes the advisory to the Engineer-in-Charge without naming the office. Hiru News, filing at 1.27 p.m., identifies the body that acted as the Mahaweli Authority, and gives the same 150 cubic metres a second. Both name the areas at risk as the lower reaches of the Kotmale Oya and the stretch of the Mahaweli River below the Kotmale dam.
Victoria has gone from four to six
Hiru adds that six spill gates at the Victoria reservoir opened automatically overnight as heavy rain continued over the central hills. Four gates at Victoria were opened on 10 November, affecting low-lying areas including Gampola; the count has since risen by two, and the opening was automatic rather than ordered.
Readers should note that Victoria gate-opening stories recur almost identically season after season, and that a gate count alone does not identify an event. The figures above are Wednesday’s.
One further caution on names: the reservoir spilling here is Kotmale, on the Mahaweli, and not the separate Upper Kotmale reservoir, which has had its own spill reports this season.
The same rain, elsewhere
Hiru’s filing bundles two other items from the same weather. The Colombo–Kandy main road section from the Dawson Tower at Kadugannawa to Ganethenna, closed on Tuesday for rock and earth-slide risk, has reopened, though Kandy District Secretary Indika Udawatta said vehicle movement there remains restricted. And Dr. Wasantha Senadheera, Senior Geologist at the National Building Research Organisation, said rainfall is proving hard to forecast and the public should act with caution rather than wait for formal notices.
Not reported
Neither filing says how many of Kotmale’s gates were opened, or by how much. Neither gives the spill level as a figure, names the villages at risk, reports any evacuation, or says how long the release will continue. Nothing indicates whether power generation at Kotmale is affected.