The northeast monsoon brings rainfall to Chennai in October-November. However, 2015 witnessed excess rainfall and the city was “surprised”. Rains have not been good enough in Tamil Nadu in the past. However, now and then it rains in excess and many parts of the state suffers due to unplanned development. Buildings have come up in dry lake beds (also when streams were dry). Obviously, this leads to inundation.
Several small rivers (large streams) in Chennai started to carry water. This in turn wreaked havoc along its path. Here is a waterway – probably a small stream that has been cemented to just carry water. However, parts of the embankment have not been strong enough. Possibly, water from the Chembarambakkam Lake has been released. Or this could be water from another state…
The runoff was not much – just about 2-3 feet but because the entire culvert is paved, water gains speed. Notice the small local streams serving the main stream. The culvert is reddish with sediments.
Notice the left bank – that has given away to the force of water and rain.
Fate Tectonics 