Two of the reservoirs that drive Sri Lanka’s largest hydropower cascade are closing on spill level after sustained rain over the central hills, and the National Building Research Organisation has placed five divisions in the Nuwara Eliya and Kandy districts under red landslide warnings.
The water level in the Maussakele reservoir stood six feet below spill level and Castlereagh four feet below, engineers in charge of the two hydropower reservoirs said, with both rising fast and their catchments still receiving high rainfall, the Daily Mirror reported. Those readings were taken on Tuesday morning.
Why these two reservoirs matter
Maussakele and Castlereagh feed the Laxapana, Polpitiya, Wimalasurendra, Canyon and Broadland hydropower complexes — the Kelani-basin cascade that carries much of the country’s conventional hydro capacity. Rising storage in the two heads of that system is ordinarily good news for generation, and the reason spill matters is that water passing over a spillway is water that never turns a turbine.
Neither reservoir had spilled at the time of the reports.
Red landslide warnings
Red landslide warnings have been issued for the Pasbage Korale divisional secretariat division in the Kandy district, and for Ambagamuwa, Kotmale East, Kotmale West and Norwood in the Nuwara Eliya district, NewsFirst reported on Thursday morning. Level Two warnings cover several further divisions.
Those five divisions sit directly across the Maussakele and Castlereagh catchments — the same rainfall that is filling the reservoirs is destabilising the slopes above them.
On the roads
Highways across the hill country, including the Nuwara Eliya highway, have been shrouded in thick mist morning and evening, thick enough to prevent a clear view of the road. Police have told drivers to switch on headlights and pass through the affected areas and sloping roads with extreme care to avoid accidents.
Heavy rain was also affecting Colombo and surrounding areas on Thursday. Police Spokesman Assistant Superintendent F.U. Wootler advised motorists to drive with headlights on in rain, and the Expressway Operations and Maintenance Division asked expressway users to keep a minimum 50-metre gap between vehicles, keep lights on at all times and reduce speed, NewsFirst reported.
Context
The same system has pushed the Nilwala and Gin rivers in the south to minor flood levels across 12 divisional secretariat divisions, and the Met Department has forecast falls above 100 mm in places. Both reservoirs approached spill level in August and went over later that month.
Not reported
The reservoir readings are Tuesday morning figures and neither outlet has published an updated level since; both may have spilled or fallen back in the interval. No report gives the rainfall totals recorded in the two catchments, says whether spill gates have been prepared, or reports any evacuation, road closure or displacement in the divisions under red warning.
A note on spelling: the Daily Mirror renders the reservoir Maussakele; our earlier coverage and several outlets use Maussakelle. Both refer to the same reservoir above Maskeliya.
