Cabomba aquatica forms a thick carpet along river's stretches, says study
A study conducted by the Kerala Sasthra Sahithya Parishad (KSSP), in association with Karunagapally municipality, Thodiyur grama panchayat, and Fisheries Department, shows that the 42-km-long Pallikkal river is dying a slow death.
The study team comprises K.K. Appukuttan, retired senior scientist from the Central Marine Fisheries Research Institute; N.C. Anil Kumar, scientist from the State Remote Sensing Agency; K.J. Prasanna Kumar, Deputy Director of the Fisheries Department; and N. Sursendran and E. Shanavas from the KSSP.
The study shows that the river is suffering from a dramatic decrease in water flow. Wanton dumping of plastic bags filled with poultry and abattoir waste also threatens it. In fact, a long stretch of the riverbed is a thick carpet of thousands of these plastic bags.
High-nutrient solutions from these wastes have stimulated an alarming growth of the aquarium plant Cabomba aquatica for several kilometres not only along the lower course of the river but also in the Vattakayal into which the river flows. The Vattakayal is the south-western end of Kayamkulam Lake.
Cause for alarm
The study reveals thick growth of the plant along five kilometres of the lower course of the river and in a 2 sq km spread in the Vattakayal.
Scanty growth of the plant can be seen for another 15 kilometres in its middle course, giving rise to fears that this stretch too will meet the same fate as the lower course.
The growth of the Cabomba aquatica is so thick that it has made navigation by motorised boats impossible. Though the study notes an abundance of edible fish in the plant-infested areas, fishermen are unable to fish owing to the plant growth. In most areas, the plants are 5 metres tall and submerged. Their pink blooms are a feast for the eye.
The study observes that neither the middle nor the upper courses of the river are safe. Rampant clay and sand-mining in idle paddy fields on either side of the river have destroyed the vegetation on its banks.
In many areas along the river's channel, the team did not recognise the riverbanks as the mined paddy fields have merged with the river.
There is also heavy sewage discharge and urban run-off in the middle and the upper courses. This prevents flow of fresh water into the river's lower course. As a result, this course has almost become stagnant. This contributes to the growth and spread of the Cabomba aquatica .
The study says that pollutants continue to flow into the river.
It suggests enforcement of rules to reduce contamination and improve water quality. Steps should also be taken to make the river fishable, it says.