TB dam water turns green, due to blue-green algae bloom

The water in Tungabhadra reservoir has turned dark green in the last few days. Environmentalists have attributed the phenomenon to cyanobacteria or blue-green algae bloom, which thrives in warm and calm waters.

Naturalist and wildlife activist Samad Kottur says chemical waste let into the waters by the factories and farms is the culprit.

Tungabhadra reservoir receives inflows from Malnad, where large quantities of chemical fertilisers are used for coffee, coconut and arecanut plantations. And the unregulated discharge of chemical waste by the factories have led to a cyanobacteria bloom, which turns the water into dark green.”

Cyanobacteria can grow quickly in sunny weather. The water will become normal in two to three weeks, he said.

The environmentalist cautioned the villagers against using dam water when it is green. “People should avoid using water when it is green for domestic consumption. They should not bath or take cattle to the water when it is green. High incidence of cyanobacteria in the water can cause skin diseases,”
he said.