To avert flash floods in the rivers that flow through Chennai, the Water Resources Department has planned schemes for conservation of resources and improving flood carrying capacity.
Widening of the Adyar and the Cooum to increase their carrying capacity and minimise flooding in surrounding areas is on the cards. For instance, the stretch of the Adyar between Tiruneermalai and Anakaputhur is only about 40 metres wide now. “We need a width of over 100 metres to reduce inundation in areas like Varadharajapuram and Mudichur. Missing links between lakes and rivers will be revived with new channels,” said an official. Moreover, flood protection wall along the vulnerable portion of river banks like Araniar and Kosasthalaiyar would be constructed to increase their carrying capacity wherever there is inadequate space for bund. This would help avoid breaches during the rainy season and illegal sand mining, officials said.
Construction of check dams and barrages across the Palar at Padalam are one of the major proposals to retain surface water and boost groundwater reserves. The department plans to reconstruct check dams in areas such as Velliyur and Gerugampoondi across the Kosasthalaiyar that are defunct now.
This would help augment groundwater recharge and create new well fields for Chennai water supply.
Moreover, massive recharge wells and shafts would be sunk in river or tank beds for aquifer recharge. “We may opt for 40 metre dia recharge wells too. Such infiltration measures are also planned in low level areas to reduce waterlogging,” the official said.
Besides flood regulators in streams, regulators at the tail-end of rivers may be proposed to arrest seawater intrusion in places like Sadayankuppam and Idayanchavadi, officials added.
