Observatories in DGP office and at Anna University recorded up to 12 cm of rainfall

The flooding in several areas on Tuesday night and Wednesday shows that the Corporation should fast-track the long-delayed stormwater works project and review the completed works for performance. Reports suggest that even in places where the full range of works including interconnects have been completed, such as in Kolathur, residents had to suffer flooding.

Some four hours of torrential rain — at 9 cm, the second highest on a single day in the month of September — brought the city to its knees with flooding, traffic snarls and water-logged educational institutions.

The weather observatories in the DGP office and Anna University had recorded up to 12 cm of rainfall. However, the northern parts of the city received only 3 cm. The city had earlier recorded nearly 11 cm of rainfall on September 26, 2003. Chennai registered an all-time high of 17.4 cm in 24 hours on September 12, 1996.

Heavy rainfall accompanied by strong winds and thunder that lasted for over four hours from midnight caused inundation in some localities that were recently covered with stormwater drains and low-level areas.

Roads in suburbs that escaped flooding were close to natural waterbodies that acted as reservoirs for the rain water. The Water Resources Department (WRD) may learn a few lessons from this and prevent encroachments to protect the waterbodies in and around the City.

Some of the areas that were flooded included Tiruvottiyur, Velachery, Perambur and Kilpauk.

According to Chennai Corporation, of the 12 water sheds in the city, stormwater drain networks have been provided in only three watersheds — Captain Cotton canal, Kolathur and Royapuram. In these three, Kolathur can be said to be near complete as far as completion of works by both the Corporation and the WRD are concerned.

For instance, J.I.A. Easter Raj, a resident of Kolathur, said Vivekananda Nagar Main Road was recently covered with stormwater drains. But, the road used by residents saw water logging as the drains were not constructed according to the road gradient, said Mr. Raj. Residents of Senthil Nagar in Kolathur too had to wade through flooded streets.

About 65 per cent of the work has been completed so far in the watersheds of Otteri Nullah, Virugambakkam-Arumbakkam Canal, Cooum, Mambalam-Nandanam, Adyar, Velachery, South Buckingham Canal, Central Buckingham Canal and North Buckingham Canal. Encroachments in many areas including Mambalam Canal have hindered work. The remaining work taken up under the Jawaharlal Nehru National Urban Renewal Mission is expected to be completed by March next year. Residents of Panaimarathotti and Meenakshiammanpettai, Royapuram, complained that some roads were waterlogged as the drains were not desilted.

Meanwhile, as the meteorological department predicted heavy rainfall for two more days, the State government has initiated precautionary measures to mitigate flooding. In a meeting chaired by Chief Minister Jayalalithaa on Wednesday, it was decided to evacuate residents of low-level areas to safer places and take measures to prevent the spread of water-borne diseases.

Schools and colleges in Chennai, Kancheepuram and Tiruvallur will remain closed on Thursday. The quarterly exam that was scheduled on Thursday would be conducted after the last examination. While Chennai Metro Rail Limited have been instructed to be prepared to pump out rain water in the trenches dug for tunnelling work, police have been asked to regulate traffic in arterial roads such as Vadapalani junction and Jawaharlal Nehru Salai.