TAMIL NADU

Aerial survey for flood risk mapping completed

Aloysius Xavier Lopez

It will help in planning flood mitigation measures for Chennai



“ALTM technology is being used for flood mapping for the first time in the country”

The project will also help to identify places suitable for groundwater recharge



CHENNAI: Aerial survey for flood risk mapping of Chennai and its suburbs using the Airborne Laser Terrain Mapper (ALTM) technology has been completed by the Institute of Remote Sensing, Anna University.

Director of the Institute of Remote Sensing M.Ramalingam said the processing of data was in progress and the 30-centimetre contour map for 500 sq. km of the Chennai Metropolitan Area would be available in three months. “The mapping is done in collaboration with a German company,” he said.

Around 75 per cent of the work has been done, said K.Srinivasan, one of the members of the team working on the project.

The maps would be ready by this monsoon. This would help in planning flood mitigation measures for Chennai which has been facing problems of water logging and clogged drains, said Dr.Ramalingam.

The ALTM technology is being used for flood mapping for the first time in the country, he added.

From a helicopter hovering over the city, laser was beamed down in order to hit the terrain and get reflected. The data, which is recorded in a sensor, is decoded and information about the undulations of the topography is generated. Using this information, the digital elevation model could be created.

“We want to identify places suitable for groundwater recharge and draw routes to divert the excess floodwater,” said Dr. Ramalingam.

Simulation of different flood situations with different measurements of rainfall would be possible with the model, he added. The findings will be helpful in taking up flood mitigation works in vulnerable areas. This can also be used as a base for all future simulation models,” the sources added.

With availability of more funds the project could have covered the whole CMA, said Dr.Ramalingam. A total of Rs 2.17 crore has been allocated for the project, he added.

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