CHENNAI : The Tamil Nadu government has classified 306 areas in Chennai as flood-prone areas, of which 37 are considered as very highly vulnerable.The mapping of vulnerable areas was done by the Tamil Nadu State Disaster Management Authority (TNSDMA) after the December 2015 Chennai floods.It is learnt that after the floods, an assessment was carried out by mapping areas as very high vulnerable ones, highly vulnerable ones, medium vulnerable ones and low vulnerable ones, based on inundation.If the water level was more than five feet due to heavy rains, it was classified as very high vulnerable areas while those having two to three feet water level were considered highly vulnerable. The areas with water level of two to three feet were considered medium vulnerable and those below two feet were considered as low vulnerable.
Initially, in the 15 zones of the Chennai Corporation, 859 locations were affected by floods. After desilting and rectification works done in the form of laying storm water drainage network, 306 areas have been identified as vulnerable and classified under the four sections.According to the TNSDMA, of the 37 very high vulnerable areas, 24 are located in Adyar Zone, which includes Guindy, Velachery, Tiruvanmiyur and Adyar. Interestingly, of the 306 flood-prone areas, 67 have been identified in the Adyar zone. During the 2015 floods, water has entered a maximum distance 1,500 metres near military causeway in Manapakkam village in Alandur taluk on the left side of the Adyar river while it entered a maximum distance of 3000 metres near Jafferkhanpet.
The Teynamet Zone, which consists of Nungambakkam, Thousand Lights, Alwarpet, Mylapore, Santhome, Triplicane, Chepauk, Royapettah and R A Puram, has five of the most very high vulnerable areas prone to floods above five feet. Interestingly, this zone is considered as highly flood prone with 65 locations figuring in the flood-prone list with 20 of them being termed as highly vulnerable areas.
The mapping of flood prone areas also highlighted the vulnerability of Valasaravakkam zone which has 26 flood-prone areas.