Chennai: “The inflow of stormwater into four reservoirs that caters to Chennai has been affected at least by 30 per cent due to red soil quarrying, development of plots and new roads. Further, there is every possibility of flooding in several parts of Chennai metropolitan area, as the outflow channel of Cholavaram, Red Hills and Chembarambakkam are also affected as part of poor urban development,” said a senior state official working closely with the state disaster management.
The inflow and the outflow hydrology of all the reservoirs are under stress and there are authorised and unauthorised buildings affecting the flow of water. Chennai saw flooding in 2015 as Chembarambakkam overflowed and we are yet to know what is in store if Redhills and Cholavaram overflow with heavy surplus above 10,000 cusecs. Poondi alone is comparatively safe, as the canals and water channels are not encroached.
Further Poondi has large tracts of agricultural lands near its sluice gates and these lands act as aquifers absorbing water flow impact. The maximum damage will be crop damages, but in case of Redhills, Cholavaram and Chembarambakkam industries and flats have come up along the water channels, the informed official said.
The state higher-ups have already warned about the awaiting danger and the chief minister had also been briefed on the subject seeking political clearance to act against the structures that affect hydrology, the official added.
“At the present flooding is witnessed only in low-lying areas of Kancheepuram and there are threats awaiting in Tiruvallur district when the surplus is released. In case of Red Hills, any outflow over 4,000 cusecs will flood the localities in Red Hills and Ambattur areas”, said Chennai metro water official source.
A large number of plots have come up in Ayanamabakkam, Ambattur, Sriperumbudur, Irrungattukottai, Nolambur and these are areas that will suffer if water is released from city reservoirs and the only respite, for now, is that the lake levels on Wednesday stood at 30 per cent of its storage capacity, the official added.