Kozhikode

Pollution eating away Kallayi river

Gone to waters: The sorry state of the Kallai river.- PHOTO: K. RAGESH  

Kallayi river conjures up images of the silent music of rain that beguiles the lonely heart. Sadly, this Environment Day, the legendary river, which is almost synonymous with Kozhikode, is a picture of degradation, thanks to toxic waste.

The river basin was a centre of international trade in ancient times. It was also the second largest centre for timber trade in the world. “Now, the river is facing a host of issues including encroachment,” said P.S. Harikumar, Scientist, Centre for Water Resources Development and Management (CWRDM).

The river, which originates from Chelakulathur in Peruvayal and covering a distance of 22 km before joining the Arabian Sea, is one of the smallest in the State. “Construction of concrete walls on the banks of the river by private individuals and dumping of solid and liquid waste are a cause for concern. Moreover, the formation of small islands due to clay and silt deposits results affects flow of water,” he said.

Amimal waste

Dr. Harikumar added that the CWRDM, which carried out a study several years ago, had concluded that indiscriminate dumping of animal waste from slaughter houses had decreased the depth and area of the river.

According to him, an analysis of the water quality parameters of the river indicated high levels of pollution. “The pH of the water was slightly alkaline in nature. The Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) were beyond permissible limits. The BOD level indicated that the river water was extremely polluted. The high COD levels indicate high inorganic load in the river.

“The concentration of tannin [wood pigment] was found to be high in Muriyad bridge; confluence point of Canoli canal and Kallayi river, and Kallayi bridge downstream of Kallayi river, but less in the upstream sampling station of the river and in the canal station. Moreover, the total coliform and E-coli levels in the water were also high,” he said.

Saline water

The tidal currents enter upstream into the river up to 20 km and hence, the water is saline. Owing to the relative shallowness of the river during summer months, the tidal currents could easily enter the river and the effects of tides were observed far upstream (18 to 20 km from the river mouth), Dr. Harikumar said.

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Printable version | Nov 27, 2020 8:48:01 PM | https://www.thehindu.com/news/cities/kozhikode/Pollution-eating-away-Kallayi-river/article14385255.ece

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