Decolourisation of River Periyar
The River Periyar in Kerala is again witnessing the decolourisation. The decolourisation of River Periyar which provides drinking water to Kochi city and adjoining areas has become the cause of worry for the people and government of Kerala. The water turned pitch black in one stream, it was milky near the Pathalam regulator-cum-bridge.
The pollution control Board (PCB) has attributed the change in colour to the poor quality of water as a result of eutrophication. PCB has stated that huge quantities of organic load in the form of sewage from nearby townships are regularly reaching the river system. This is contributing to the eutrophication resulting in the change of colour.
River Periyar flows in the state of Kerala. It originates in the Western Ghats and flows north for a short distance to Periyar Lake. Periyar Lake. is an artificial reservoir created by Mullaperiyar Dam across the river. From the Periyar Lake, tunnel carries water through mountains to the Vaigai River in Tamil Nadu, where it is used for irrigation.
Further downstream Idukki dam is constructed across the river. The river descending out of the mountains into the coastal plain and empties into the Arabian Sea.