CHENNAI: The ‘comprehensive’ flood mitigation project for Greater Chennai and its peri-urban areas in Kancheepuram and Tiruvallur districts, at a total cost of Rs 3000 crore, has received the ‘in principle’ approval from the Centre and work is set to commence by the end of the financial year, according to PWD officials. 

The mitigation project, that was proposed by the Commissionerate of Revenue and Disaster Management in May this year, also covers vulnerable urban areas in other coastal districts of the State. Apart from reducing vulnerability to floods, the project is expected to result in creating additional storage for about 4.76 TMC of water, by formation of new reservoirs in Adyar and Kovalam basins and in-stream reservoirs in lower Palar, Adyar, Kovalam and Kosasthalaiyar basins. 

As far as Chennai is concerned, rehabilitation, bio-remediation and deepening of PWD tanks in South Chennai Metropolitan area, feature in the proposal at an estimated cost of Rs 10.17 crore with cut-and-cover macro drains for missing links between tank systems at a cost of Rs 688.42 crore.

“We have included almost all South Chennai tanks including Adambakkam, Muvarasampattu, Madipakkam, Narayanapuram, Pallikaranai, Kovilambakkam, Sembakkam and Chitlapakkam lakes, at a total estimated cost of Rs 880 crore,” said a PWD official. 

Climate change factored in
The freeboard (the vertical distance between the normal maximum level of the water surface and the top of the sides of a levee) of tank bunds and flood banks, are to be increased from 0.90 m to 1.5 m to ‘buffer flash flood due to climatic change scenario’, according to the project proposal. 

This, along with increasing the linear waterway and providing flood regulators in irrigation tanks and flood protection works in Cooum, Adyar, Kovalam, lower Palar, Kiliyar and Ongur, is to be taken up at a total cost of Rs 908 crore.