A study conducted by Centre for Urban Water Resource (CURE) of Dhan Foundation revealed that physical, chemical and biological parameters of the Vaigai are unfit for use. The samples lifted from eight out of nine spots of the Vaigai were found to be unfit for human use.
The members of the CURE had conducted a study titled ‘Urban Vaigai- Under Isolation,’ which was released in Dhan Foundation’s magazine ‘Water Watch.’
The study said that ancient Tamil epics like Silapathikaram, Agananuru, Purananuru, Kalithogai and Thiruvilaiyadal Purnam had spoken about a thriving Vaigai river. However, the river is full of prosopsis juliflora, water hyacinth, sewage and solid waste due to urbanisation. The Vaigai is completely alkaline in nature. The samples lifted from the check dam at Ismailpuram showed the presence of ammonia, which is an indicator of high level of degeneration. The dissolved oxygen in the Vaigai varies from 1 to 4 mg per litre. Usually, a value of zero dissolved oxygen would indicate that the river is technically dead.
Similarly the levels of Biological Oxygen Demand, which is an indicator of contamination, varies from 30 to 120 mg per litre. The Panthalkudi channel contributes to the maximum load of contamination to the Vaigai. In the core city, growth of water hyacinth in the river indicates the presence of nutrients. Restricting sewage and solid waste into river is the only way to safeguard the Vaigai.
The team made a field visit to the Vaigai starting from the Kochadai pumping station to Viraganoor regulator to understand the present condition of the scenario. It has classified 11 km of the urban river into four segments. It said retaining walls and four-lane roads laid along the Vaigai under the Vaigai Riverfront Development of the Smart Cities Mission must consider the water holding capacity to prevent any possible flood. There is a need for collective action to prevent further deterioration of the Vaigai and to protect the river.