Usha Rani Das
Chennai, Oct 23: Though almost every building in Chennai has Rain Water Harvesting system, pools of water have appeared in front of the apartments and buildings. After a continuous downpour of rain for two days, Chennai streets were water clogged, causing people tremendous problem in carrying out their daily chores.
“Even if it rains for an hour or so, water collects in front of our apartment. We don’t know whom to approach to solve this,” said Sheethal Gunasekharan, a resident of Kalakshetra colony, Besant Nagar.
The rain water harvesting system (RWH) of Chennai seems to fail in its aim to divert the water into recharge tanks and sumps. The water which was supposed to flow thorugh the rooftops pipes into the recharge tanks on the ground, either flows out of the tanks due to overflowing or are clogged in the pipes.
“Mud and silt clogs the openings. The RWH pipes are not cleaned properly. The Corporation engineers don’t monitor the system regularly. Even if they do, they don’t do a great job,” said Dr. Sekhar Raghavan, the Rain Man of Chennai who pioneered rain water harvesting in Chennai.
Raghavan also said that the Corporation engineers do not know the proper mechanism to clean the pipes thoroughly.
Alexander, another resident at Parvati Street said, “We complained to the Corporation. People came and cleaned it last year. Still water collects.”
Water-clogged streets have slowed down the traffic and some routes are closed. The auto rates have gone up. The pedestrians don’t have safe place to walk. The roads are full of water filled potholes which makes the roads accident prone.
Not only this, due to flooding of the drainage system the streets are filled with mud, sewerage and garbage.
“The drainage system as well as the Corporation is at fault. There is no proper guidance. If you take Mylapore, the drainage system was connected to ponds, so water will automatically move out through it. Now there is no such system. Whatever system is there, it is not maintained properly. All the wastage blocks the drains and there is no person to clean it,” said Dr. M.B. Nirmal, founder of ExNora International, an organisation which is campaigning for Cleaner Chennai.
When the Metro Water Supply and Sewerage Board was approached for a comment, Public Relations Officer said they do their job properly.
The drainage system was built long ago. The parameters on which the pipes were built then changes over time. The roads which were previously convex have now become concave due to wear and tear over time.
“When the city was built, the surface was more permeable. Hence most of the rainwater was soaked through the surface. Now with these concrete roads, the water can’t get through and hence collects on the sides of the road. The pipes were not built to handle such workload. Hence the drains overflow,” said Durgesh Kumar, civil engineer who is pursuing his PhD. at IIT-Madras.
Sekhar Raghavan said the flooding of streets increases as open spaces shrinks. There is no space for the water to flow through to the ground.
“The lakes and ponds are filled with garbage and then covered up with cement for buildings and apartments to be constructed over there. With the construction of roads with tar and bitumen, the surface becomes impermeable for the rain water to soak through. How can the rain water permeate?” said Raghavan.
There is also lack of awareness among people about RWH. For this, Rain Centre, an organisation started by Raghavan in 1988 organised a series of 15 workshops on Rain Water Harvesting for media, architects, builders and municipal engineers.
Tamil Nadu Government was the first State Government to make it mandatory for every building to have RWH system in 2001. With Chennai facing water crisis, the RWH system was built to collect rain water into sumps or recharge tanks or divert the water from driveways and roads directly into the soil, for reuse of that water.