Chennai's ground water needs to be replenished. The best way to do it is through the system of rainwater harvesting. But how many people are willing to implement it? GOUTAM GHOSH examines the scene.

Though Chennai has not yet been whipped by rain as it was during the November 1984 cyclone, it has run for cover from an occasional late-night snapshot shower and mid-day downpours over the past few weeks. Waterlogging has been as predictable as the annual moulting of the road surface. Layers of asphalt have been peeled off much to the chagrin of pedestrians and other road users, but to the relief of Government-approved contractors and public servants associated with the process.

Despite the much-hyped stormwater drains in Chennai, water continues to collect quickly. The swirling mess doggedly hugs the road surface and refuses to budge for days.

Most of you will agree that instead of allowing the water to rest on the road for days, to overload the sewer network and to flow eventually into the Bay, it could be helped to seep into the soil.

Chennai, the megapolis, has 2,200km of roads. If you take the average width of all the roads taken together, it is likely to be about 15m. Even if you take the average width to be 10m, the amount of water from rain falling on the roads during the southern monsoon is roughly 2,640 crore litres. An impressive figure, even if you ignored the rain that falls on the buildings of Chennai. The rain on private and public buildings is promptly routed through pipes to spill on concrete-paved areas. This water flows down to the roads, adding to the mess.

The spread of the rainwater harvesting concept seems to have accelerated faster now in the public consciousness than ever before, but there are residents who still harbour doubts. A doctor, who owns a tall building in Anna Nagar and which he has rented out completely, refuses to be convinced as doggedly as his son that it is imperative for him to harvest rainwater. His building is three-storeyed, and the CMDA notification states that such a building is required to have an RWH system. But he and his builder have managed to evade that responsibility through well- familiar channels — using legal tender to seal any action.

But there are many who are convinced because the handful of RWH experts who can instal a working RWH system are hard-pressed for time. The demand for the service exceeds the total productive capacity <15,0M,,0>of the system as on date to fulfil it.

A typical system is simple. You have to connect pipes from the terrace and direct the water to the open well in your house. And if you have a borewell, you can create a filtration bed of sand and rubble (broken bricks), and direct the pipe from the filtration bed to the borewell. This is important because you, as a responsible citizen, would certainly not like to contaminate the groundwater.

There are many adds-on to a simple system. You could have a tap to flush out the terrace water before directing the rainwater to the well. You could instal a PVC tank to store water for use in your bathrooms. You could even use the water for drinking and cooking if you instal a system to filter and disinfect the water.

The basic system is so simple that you can design your own and get a mason to instal it. You don't need to be a civil engineer to harvest rainwater. But there is no harm if you seek the services of an expert. The cost difference between a consultant-executed work and self-done RWH is likely to be slight, provided the consultant does not charge a very high fee. But essentially it is a small price to pay for avoiding the headache of getting masons and materials, and supervising the work. A reasonable fee to an RWH consultant to instal a permanent system would be a tiny fraction of the discounted present value of consultation fees one would pay for various services in 25 years -- including paying for tankerloads of water during the crunch months of summer.

Despite the simplicity, people still baulk at the thought of investing in RWH. Tapping rainwater leaches the salts in the well. The rainwater-diluted water from a well or a borewell tastes better. More important, it adds to the groundwater stock from where drawal has been mindlessly stock-depleting so far. Where the soil is sandy, benefits of RWH may not be immediate. But instead of a guaranteed groundwater depletion in due course of time, the water stock would be renewed if everyone harvests rainwater. Since the hydrological cycle is almost axiomatic, water is technically a renewable resource. But fresh water needs to regenerated.

It was relatively easy for the Ramon Magsaysay Award winner, Mr Rajendra Singh of Tarun Bharat Sangh, Rajasthan, to motivate the illiterate villagers to build checkdams to replenish the water-depleted soil. Because he had to convince the unlettered villagers and they rallied behind him once he took up the spade. It is most difficult when one has to convince the educated lot. Each will raise a relevant question for which there may be no easy answers. Once the question begs a reply, the educated lot is convinced that RWH is of questionable validity.

But if you think about it you will agree that there is nothing uncertain about RWH. If you don't refill the bottles in your fridge, they are going to be empty soon. Groundwater is no different.

Then how can everyone, including the rational, sceptical lot, be compelled to harvest rainwater? Through force. Twist the reluctant arms. Through punitive laws. The State needs laws to achieve what promotional efforts can but only over a very long period of time, and that too not everyone even then will agree to harvest rainwater.

We need a stiff law that provides straight guidelines and stiff penalties for violators. Just as the compulsory helmet rule worked like magic over a decade ago, so will this law — if it is implemented seriously. The law may hurt now, but in view of the future generations a little hurt now may be tolerated. After the law come into effect, those who are cash-strapped could approach the banks for loans at low rates of interest to instal RWH system. There may be misuse of this facility but on the whole, aberrations and collusions with bank officials may be more an exception than a regular trend.

We badly need to recharge the groundwater. For that we need to have a bird's eye view of the process and its linkages. The execution has to be holistic and simultaneous. Implementation of laws, training of masons, monitoring the systems, providing water tax incentives to those who comply, keeping track of the prices of inputs. A tough job. But it can be done.