A group of civil engineering students are upbeat about their idea — channelling rainwater to meet the water shortage in Chennai.

When Vignesh Chandiramouli and his friends — B.Tech. (Civil) students from Sri Sairam Engineering College, Chennai — had to submit a project report, they went into a huddle. Suggestions varied, but they were sure about one thing. They would pick an everyday civic problem and find a workable solution; even if time was short and the project was meant for college credits alone.

They did not have to think much. Two years of drought in Tamil Nadu had depleted groundwater supply throughout the state.

Chennai had been hit by severe water shortage. The rains came this year, bringing fresh water, but even as they watched, it was being drained into the sea. Households mandatorily harvested rainwater, but the rainwater collected in the stormwater drains that criss-cross city roads finally entered the sea.

The irony of this was not lost on them. With salt removed in an expensive treatment plant, the same water was supplied to the city! “Our idea was to show how rainwater was wasted when it was allowed to flow into the sea,” says Vignesh. “Groundwater level in Chennai is decreasing at a high rate and we have to use run-off water for recharging it,” says S Naveen Kumar, his team-mate.

Another student from this group, G Prabhu, says, “We wanted a project that would talk about the importance of rainwater and ways to use it effectively.”

Chalking out a plan

“We wanted to talk about how the purest source of water is available to us for free,” says V Vinodh, who is part of the group. They would meet Mr. Sekar Raghavan of the Rain Centre to get their basics right. That was the easy part. The tough part was estimating the quantity of rainwater and finding the groundwater levels for different places in Chennai — before and after the implementation of rain water harvesting (RWH) system for houses. The collection and study of existing drain patterns was difficult, so was travelling to different places in the city — Ripon building, Mylapore, Besant Nagar, Velachery, T. Nagar — to get information on the annual rainfall intensity and drain specifications, they said.

All that is behind them. Their report has been submitted. It has fetched them maximum grades. The civil engineers now hope that the Corporation of Chennai will focus on recharging the ground instead of just disposing of the rainwater. “Methods suggested by us for rainwater harvesting for different soil profiles will be of great use,” says Vignesh. “If they are implemented, water shortage in summer can be met, while run-off from the roads can find proper outlets.”

Naveen Kumar is sure that their ideas can play a major role in bringing down the water shortage in the city. “Approximately 65 per cent of the rainwater falls on the roads and is directed towards the sea through the major basins,” he says. The report shows ways to use the run-off water in efficient ways, says Prabhu. Vinodh wants the wasteful disposal of the run-off water to stop. We can make good use of it, he says.

The water-divining mission gave them unforgettable memories, the students say. In Velachery, they were shocked to find a temple tank that could store a million litres of water in total disrepair. They had to climb the top of a house to take pictures because it was covered with plants and was almost invisible from adjacent roads. A canal in Velachery had muddy water in the initial stretch and very clear water beyond a point. “We followed it for a kilometre and the amount of water in it equalled that in the Cooum river. It can be used for taking up the rain water from the nearby roads.” Meeting people across the city with varied interests was a useful experience, they say.

A crucial take-away of the project is what people don’t know. “Everyone should know where the run-off from their street is going,” says Vignesh. Most citizens are not aware that the stormwater drain network takes rainwater to the sea, says Naveen. They do not know that the sewage and rain water are taken through separate pipes; they call it drainage in general. Householders should support recharging the ground with run-offs. “Householders should compile a report about this,” says Prabhu. “People hardly realise that the purest source of water is being criminally wasted.” Those who know this must take the responsibility to save it, says Vinodh.

“More students should take up such projects that tell us about managing our natural resources,” says Sekar. “This will help in sensitising youngsters to the damage caused to our environment.”