Thumbs up for Puthanar revival plan

THIRUVANANTHAPURAM: The irrigation department has  welcomed the idea mooted by Power Minister Kadakampally Surendran to have permanent weed remover machines to clean the man-made Parvathi Puthanar river round the year. Presently, tenders are being given from time to time for pushing weeds and water hyacinth out to sea via Akkulam lake and Poonthura using pond dunes.

The cost of each cleaning comes up to around Rs 1 crore. However, the benefits are undone as water hyacinth grows by around 100 per cent in a few months and block the water flow. Subsequently, the flood carrying capacity is affected soon after summer.

“In Chennai, they have placed permanent devices to clean up Koovum. The minister has proposed a mechanical remover here also. This can cut down the cost of cleaning if we are persistent in operating it. However, the problem is that over 200 to 400 tonnes are dredged out during  each clean-up and there is no space left in the city to dump them,” said a senior official attached to the inland navigation section of irrigation department.

During summer,  the discharge of treated, grey water from Muttathara sewage farm is increased to maintain the Parvathi Puthanar water flow and minimise weed growth. The Vallakadavu-Puthanpalam stretch of river is the most polluted in the stretch as piles of plastic used to surface from river after each set of clean-up.

As per experts, mechanical removal of hyacinth by the Inland Navigation department is the most expensive way to battle weed. A decade-old draft plan had suggested flushing of the river with sea water.   “If you increase the salinity of water, the weed and hyacinth will definitely be eradicated. However, it is unknown whether our indigenous freshwater fishes will be able to migrate to avoid salinity like a few foreign species” the officials said.