About 25 families were left stranded when 15 spill gates of the Thabbowa reservoir in Puttalam were opened.
The Disaster Management Center said a special group with six divers from Sri Lanka Navy were deployed to find the affected families. The Sri Lanka Air Force will also aid them.
Meanwhile, 27 sluice gates in the Rajanganaya reservoir and two in Mahawewa were opened.
The Irrigation Department stated that Nuwarawewa, Tissa wewa and Basakkulama wewa are about to spill.
After the dam of Maha wewa collapsed, the Thalawa and Thambuthegama area were flooded in the Northern Railway Line disrupting train service.
Train from Fort temporarily stopped from Thambuttegama, the Sri Lanka Railways said.