The ambitious ₹3,000-crore proposal to implement a comprehensive flood mitigation project for Greater Chennai and its peri-urban areas in Kancheepuram and Tiruvallur districts may take off in six months. The Central government recently gave its nod to the proposal and has recommended it to the World Bank for loan assistance.
A detailed project report has been submitted to the World Bank for funding. The project, which was proposed by the Commissionerate of Revenue and Disaster Management, will also cover other vulnerable coastal districts such as Cuddalore, Ramanathapuram and Thoothukudi.
The various projects in different river basins, including lower Palar, Araniyar and Kosasthalaiyar, when implemented, will help reduce the vulnerability of several localities to floods. An additional storage of nearly 4.76 thousand million cubic feet will also be created to cater to the drinking water needs of the city and its fringes, said sources in the Water Resources Department (WRD). Such interventions will not only mitigate floods but also strengthen the city’s capacity to tackle drought.
Besides forming new reservoirs to store surplus flood water in the Adyar and the Kovalam basins, riverine reservoirs will also be built in major waterways, including in the Adyar river, at a cost of ₹80 crore. These structures will come up on the stretch of the river near Adhanur, Somangalam and Varadharajapuram. Flood banks will be raised to create a riverine reservoir, a storage structure in the river.
Pollution control
Sources in the WRD said waterbodies owned by the Department in south Chennai, including Narayanapuram and Kovilambakkam, would also be deepened to revive their storage capacity. Bio-remediation efforts would be initiated to control pollution of the lakes.
Waterways in Tiruvallur and Kancheepuram districts will also be improved with flood protection walls. Nearly 21 cut-and-cover macro drains will be built between waterbodies to bridge the missing links in surplus channels and reduce water logging in neighbouring areas. For instance, macro drains will be constructed to carry surplus water from waterbodies in Irumbuliyur and Peerkankaranai to the Adyar river.
Various structures, including check dams, recharge wells and sub-surface dykes, will be constructed in rivers as part of the project, to enhance groundwater recharge and storage. Government agencies have also incorporated features to reduce the impact of climate change on waterbodies. Increasing the flood banks of waterbodies in Tiruvallur and Kancheepuram districts from 0.9 m to 1.5 m, to buffer flashfloods, is one approach, said sources.
