Following a spell of rainfall, residents in the city have begun urging the Greater Chennai Corporation (GCC) and the Public Works Department to initiate measures for monsoon preparedness, and desilt drains, canals and waterways.
Usually, the GCC commences desilting of stormwater drains (SWD) and canals a few months ahead of the onset of the northeast monsoon in October. This year, however, many drains along key areas have not been desilted, residents said.
T. Nagar Residents’ Welfare Association representative V.S. Jayaraman of Motilal Street said most of the roads in T. Nagar get waterlogged. “Most of the stormwater drains in T. Nagar are clogged because of the dumping of waste by shopkeepers. Most streets have waterlogging [issues]. There is no proper connection of drains to major waterways. Stormwater drains are also dysfunctional. The Corporation should find out who’s letting sewage water into the stormwater drains. Food waste dumped by eateries in T. Nagar remains a challenge,” Mr. Jayaraman said.
“We beseech the GCC to take up desilting of SWDs in the right earnest and ensure that the contractors do a clean job. The GCC should rope in residents’ welfare associations or resident-activists of [the respective] streets to monitor the work. A complete overhaul of SWDs is a must in the streets abutting Usman Road and other streets in T. Nagar, in view of the fact that most of the SWDs are being used by commercial establishments and mobile eateries to dump garbage and food waste. The civic body should also check as to why SWDs, which should remain dry in non-rainy seasons, always contain sewage water, and take stringent action against those who let sewage into the SWDs,” he added.
Former Corporation Councillor S. Mangala Raj said the GCC has desilted only VIP routes such as Santhome High Road. “Lazarus Church Road and Mundakanniamman Koil Street have not been desilted,” he said. Pointing to a delay in the construction of SWDs along many roads, Mr. Raj said this was leading to inundation in many localities.
‘No lessons learnt’
S. Janakarajan, former professor at the Madras Institute of Development Studies, said the city’s drainage network is not prepared for the northeast monsoon, expected later this year. “Thousands of kilometres of stormwater drains are choked. For the city as a whole, we have not learnt any lessons from the past. We do not know how to handle a good monsoon or a bad monsoon. We need structural changes in the drain network, which takes care of all waterbodies, too,” he said.
Pointing to the failure of civic agencies in modifying certain elevated sections of rivers such as the Adyar, even after the 2015 floods, Prof. Janakarajan said flooding in Ekkatuthangal was caused because of an elevated portion along the Adyar river.
‘80% water lost’
The Adyar river is also elevated near the Chennai International Airport, which causes flooding in the area. “Chennai can save 8 to 9 TMC (thousand million cubic feet) of water by diverting all stormwater drains to waterbodies and other reserves such as temple tanks. We get 1,350 mm of rainfall every year. But we lose 80% of water by surface run-off,” he said.
‘Water stagnation has reduced in many areas’
Chennai Harbour MLA P.K. Sekar Babu said the desilting of stormwater drains had not started in any of the stretches in his constituency this year.
K. Murugan, a resident of Elango Nagar, South Gandhi Street, in Kottivakkam, said a portion of a drain in the area had become dysfunctional because of construction activity in the area. “Inundation has been reported in many houses in our area,” said Mr. Murugan.
According to data compiled by experts who have been studying the flood preparedness of the city, over 25% of the total area in Chennai, including Velachery, Madipakkam, Alandur, T. Nagar, Mambalam, Chetpet and George Town, are prone to inundation.
“Most of the 210 waterbodies have not been desilted. There is no scientific desilting. There is a lack of monitoring. There is no engineering guidance,” said an expert who did not wish to be named. “What we need is an integrated master plan for water. In areas such as Hong Kong, an underground reservoir has been developed to store tens of millions of litres of water.”
Most of the projects to ecologically restore lakes have not taken off. For example, the Velachery lake’s restoration has been delayed, causing flooding of the neighbourhood. Last week, Revenue Department officials marked 1,700 houses that have encroached upon the lake. Even the Adambakkam police station has been constructed upon what’s a part of the Velachery lake. Houses and government buildings have to be demolished to improve flood preparedness.
“There are two kilometres of encroachment along the bund. The Velachery lake has been reduced [in size] from 250 acres to 55 acres,” said an official.
A GCC official said the civic body had desilted 65% of drains so far. “We will complete desilting work ahead of the onset of the northeast monsoon,” he said.
Article source: https://www.thehindu.com/news/cities/chennai/35-of-chennais-stormwater-drains-are-not-ready-for-rains/article29128753.ece