Tamil Nadu to link city lakes with four river basins

CHENNAI: In a bid to counter flooding in the city, the State government is looking at interlinking city’s lakes and tanks with Cooum, Adyar, Kosasthalayar and Kovalam basins and has asked consultants to identify the water bodies with linkages.

It is learnt that during a meeting to discuss proposed State Emergency Operation for Chennai, Greater Chennai Corporation and other urban local bodies in the four basins to set up and operationalise a real time flood forecasting and spatial decision support system, the consultants were told during a pre-bid meeting that they have to identify lakes, waterways and linkages in order to understand the behaviour of hydrology in the four basins. 

Sources said that based on the hydrology report, the consultants will have to suggest proposals for interlinking of waterways and lakes. The consultants will be using the Light Detection and Ranging (LiDAR), a remote sensing method, to identify the lakes. Airborne LiDAR maps will be prepared for Cooum (489.32 sqkm), Adyar (1162.46 sq.km), Kosasthalayar (1949.32 sqkm) and Kovalam (472.75 sq km).

LIDAR Survey is the costliest component of the project and usually consumes around 30 per cent to 40 per cent of the project cost. Sources said in addition to the rainfall events, the tidal levels appropriate for modelling computation is also to be arrived at based on the tidal heights variation in Chennai, by appropriate data from concerned authorities. The alerts shall incorporate the tidal height variations and storm surge height due to impending cyclones.

Sources said the consultants will also provide ground water details, which are required to understand the sub surface saturation of aquifers in the region. The study is being conducted for ‘Planning, Setting up and Operationalizing a Real Time Flood Forecasting and Spatial Decision Support System for Adyar, Cooum, Kosasthalayar and Kovalam Basins’ for flood management in the basins. 

Besides, the consultants will be developing a web portal (GIS based) to provide access to knowledge base, satellite and other datasets and climate forecasts. They will also develop schematics for the entire basin systems with pertinent information on flows, lake levels, etc.