Minor flood warning for Kelani River basin as Canyon Reservoir spill gates opened

The Irrigation Department has warned that a minor flood situation could develop in the Kelani River basin within the next 48 hours, after heavy rainfall in the river’s upper and middle catchment areas.

The warning covers low-lying parts of the Kelani River valley in the Dehiowita, Ruwanwella and Seethawaka Divisional Secretariat divisions. The department said there is a severe risk of a rapid rise in the river’s water level, with high-intensity heavy rain likely to continue.

Disaster management authorities have urged residents in the affected areas, and anyone using the river, to remain highly vigilant and exercise caution.

Canyon Reservoir gates opened

Separately, two spill gates of the Canyon Reservoir have been opened by six inches each, the Disaster Management Centre said.

Authorities added that, depending on the water level, a need could arise to open the spill gates of the Lakshapana Reservoir as well. People living in the lower areas of both reservoirs and along the rivers below them have been asked to stay alert and follow instructions issued by the relevant authorities.

Context

Canyon and Lakshapana are part of the Laxapana hydropower complex in the upper Kelani catchment, so water released from them feeds down into the same river system now under a flood warning. Releases from the reservoirs and runoff from the catchment combine to lift levels downstream, which is why the Irrigation Department’s warning and the Disaster Management Centre’s spill notice arrived within roughly half an hour of each other on Saturday morning.

The warnings follow the Met Department’s Amber advisory for heavy rain, issued the same morning, which forecasts rainfall above 100 mm at some places in the Western, Sabaragamuwa and North-Western provinces and in the Kandy, Nuwara Eliya, Galle and Matara districts until 6.00 a.m. on Sunday. The Sabaragamuwa and Western provinces together contain most of the Kelani basin.

The same weather system prompted the Fisheries Department to bar small boats from the western coastal belt on Saturday.