TN maps flood prone areas in Chennai; 37 considered to be very highly vulnerable ones

Chennai:

Tamil Nadu government has classified 306 areas in Chennai as flood-prone areas of which 37 are considered to be very highly vulnerable ones.

The mapping of vulnerable areas was done by 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 areas. The areas with water level of two to three feet were considered medium vulnerable areas and those below two feet were considered low vulnerable areas.

Initially of the 15 zones of Chennai Corporation, 859 locations were affected by floods. After desiltation and rectification works done in the form of laying storm water drainage network, 306 areas have been identified as vulnerable and have been classified under the four sections.

According to TNSDMA, of the 37 very high vulnerable areas, 24 of them are located in Adyar Zone, which includes Guindy, Velachery, Thiruvanmiyur 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 1500 metres near military causeway in Manapakkam village in Alandur taluk on the left side of Adyar River while it entred a maximum distance of 3000 metre near Jaffarkhanpet.

Teynamet Zone, which consists of Nungambakkam, Thousand Lights, Alwarpet, Mylapore, Santhome, Triplicane, Chepauk, Royapettah and R A Puram, has five of thet most very high vulnerable areas prone to floods above five feet. Interestingly, this zone is considered 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 Valsaravakkam zone which has 26 flood prone areas of which four have been classified as very highly vulnerable (above fife feet water inundation).

The mapping also highlighted that the cities have 84 areas which are highly flood prone, one as medium vulnerable one and 184 as low vulnerable areas (below 2 feet of inundation).

Classification of Vulnerable areas:

Areas of Very High Vulnerability (above five feet water): 37

Zones: Adyar (Guindy, Velachery, Thiruvanmiyur, Adyar) -- 24; Teynampet (Nungambakkam, Thousand Lights, Mylapore, Royapettah, R A Puram, Triplicane, Chetpet, Alwarpet, Santhome) -- 5;  Valasaravakkam ( Nerkundram, Maduravoyal, Karambakkam, Ramapuram, Valsaravakkam and Porur)--- 4; Anna Nagar—1; Madhavaram –2; and Tiruvottiyur—1;.

Areas of High Vulnerability (inundation level 3-5 feet): 84

Teynampet – 20; Adyar: 17; Valasaravakkam-- 13; Tiruvottiyur--- 7; Madhavaram:---6; Tondiarpet (RK Nagar, Kondungaiyur, Vyasarpadi, Perambur, Tondiarpet)—7; Sholinganallur: (Sholinganallu, Semmanchery and Uthandi)-- 3; Kodambakkam: (Vadapalani, Saligramam, Virugambakkam, Kodambakkam, Ashok Nagar, MGR Nagar, Thiyagaraya Nagar and Saidapet)—9; Royapuramm -- 1; Anna Nagar--- 1: