Thanks to all who have ...

Thanks to all who have provided valuable insight on the subject.I am inspired by Flood water containment Tanks interlinked that Tokyo has built and wish to propose that on the vast Flood Plains of Rivers in India, rather than Habitats and Infrastructural Bridges and Elevated Highways bisecting the flood plains, it is possible to use deep underground spaces to create Flood and Storm water retention structures that can release waters to augment River Flows when required.The top cover of soil can be retained as it is.We must think of using part of Flood Plains to store surface waters for multiple uses including creating more space for allowing flood waters in. Rest of it is as per practices fillowed world wide.

I will research more on the wealth of materials provided in response.

Best Regds

Lokesh