Despite the technological advances that mankind has made a vast majority still do not have access to potable drinking water. We are all familiar with the fact that women in some villages have to walk hundreds of kilometers to bring home a few pots of drinking water. However, the fact that, there are areas in the major metros of this country, where families depend on water is still supplied by tankers once a week, might shock a few of us.

Did you know that harvesting rainwater is one of the simplest and affordable ways of ensuring that you leave behind the legacy of a world that is green and where this precious liquid- water is still available in abundance? With the population growing at a phenomenal rate despite constant reminders of the hazards that it might pose for the future human race and the limited availability of both groundwater and surface water, homeowners have to learn to use and recycle this precious natural resource.

Though rainwater harvesting has been in practice from time immemorial starting from the Thar desert, kul and bamboo irrigation methods and temple tanks, the importance of it had dwindled considerably. Traditional rainwater harvesting is still prevalent in rural areas, in surface storage bodies like lakes, ponds and irrigation tanks, temple tanks etc. In urban areas however, due to the shrinking of open spaces, rainwater has to be harvested in order to ensure that the ground water level goes up.

Most of Chennai city was practically living on their borewell’s whch gave potable water for years. But then as the ground water level started going down. The water level in the wells receded considerably. But around that time people did not know much about rainwater harvesting. So, most of the chennaites who had bore wells made them deeper and those did not have them dug up new ones. This worsened the situation and in the year 2000 there were a situation where you buy water through tankers. Chennai city saw a certain point where there was saturation of the natral resources. However, soon after that there was a lot of pressure from the corporation to have rainwater harvesting done. Ever since the water level has gone up considerably.

Advantages of rainwater harvesting:

The process in itself is not very expensive, but, has a lot of benefits - for instance the water getting collected from the rooftops get chanellised into the ground and the other water is usually stored in tank… Secondly, since most of the Chennai residents have a borewell, further expenditure was curbed. The other things needed are- a row of soak pits, which were concealed, below the ground. Thirdly, you do not need to allocate separate space to have rainwater harvesting facilities.

Cost Involved:

The setting up cost can vary. This is because it depends on two main factors- the area of the roof and the structures that will be used to harvest rain.

· Helps you cut down on your water bills (especially in cities where people have to buy water).
· Reduces demand on the municipal water supply.
· Makes efficient use of a valuable resource.
· Reduces the possibilities of the occurrence of natural calamities such as floods.
· Reduces soil erosion.
· Prevents the contamination of ground water.

Thus, rainwater harvesting is the need of the hour. “Unless we get rainwater harvesting as a movement we do not have a bright future and for that people have to be motivated to make this a habit.” The objective is not only to ensure a better tomorrow for our future generation, but it is something we need to do to save the planet and the human race.

Rainwater harvesting is one simple method of overcoming recurring drought or scarcity of water in all parts of India. The idea is easy to implement and the costs are minimal, but the benefits are enormous. This is particularly true for a monsoon dependent country like India, where the rainfall is heavy in certain areas during specific periods of time only and is known to fail occasionally.

The basic idea in harvesting of rainwater is to direct all excess water during the monsoons to a specific area for storage or to recharge the ground water in the underground aquifer. 90% of the rainwater during the monsoons flows down the slopes to the nearest rivulet and finally to the river and the sea. Very little water goes to recharge the diminishing ground water levels in your immediate neighbourhood. Due to the increasing number of bore wells and wells in the cities, the ground water levels are rapidly sinking whereby such supplies become unreliable just like the city/town corporation water supply.

In fact, in cities and towns on the coast, the sinking water table actually will cause sea water to enter the aquifer and contaminate the fresh water supply and the existing soil. The main idea is to try and divert the flowing water to recharge the ground water in the ground close to the existing wells or bore wells. All the rainwater is directed to flow into specifically located areas within the boundaries of the property, so that it soaks into the ground with the best possibility of recharging the ground water supply immediately below the property.

This water can be used to recharge the existing wells/bore wells, displace the hard ground water and provide suitable water for drinking and other purposes. This method involves some simple surveys and a few strategically located sinkholes to direct all rain water flowing out into the ground itself. The costs and implementation of the system are minimal.

The other rooftop water harvesting involves directing all rooftop rainwater to an underground tank, passing through a simple filter like a block of lime and into the cistern or reservoir. Some cities like Dwarka and Chennai have adopted this method effectively. In fact, some city corporations are making rainwater-harvesting compulsory for all new schemes and projects. If properly designed and used only for cooking and drinking, rainwater stored in underground tanks can last up to two years.

This can be used as a supplement to the regular city water supply, hence saving some costs. Water harvesting assumes greater importance in India, a country overstretched in terms of money and infrastructure. With rising costs and population, these methods can be adopted profitably in both urban and rural areas. In fact, roof top water harvesting system must be made compulsory for all new buildings in all towns and cities in India, and encourage this in the existing buildings also.

The final harvesting method is check dams. These are small bunds or dams, built in strategic locations in rivers and lakes, that can hold both rain and river water. So water which would normally just flow away to go to waste unused into the ground. If well located and properly built, these dams can store water and help prevent scarcity for a major part of the year.

If well designed and constructed, these need little maintenance, unlike large dams, which have other major problems like seismic issues and displacement of people. In some districts of Rajasthan, these methods have made people self-reliant and provided them relief from the vagaries of the uncertain monsoons. In fact, these simple techniques have provided water for some villages with water throughout the year.

The method is very cost effective and easy to plan and implement throughout the country.

Unfortunately, rain harvesting, as an effective tool to overcome drought and water shortages in India, has not received sufficient attention from the government and NGOs. The state authorities must take the lead and encourage the city and town planning departments to increase awareness of rain harvesting and make it mandatory for all new buildings and projects. The municipal corporations must make it part of the process of planning and development in the cities and towns. This will encourage conservation of water and enhance the water supply automatically. Bangalore, Chennai, Pune and New Delhi corporations have already taken the lead in encouraging rainwater harvesting. States like Rajasthan, Gujarat, Karnataka, Tamil Nadu and Maharashtra have also provided the initial impetus in this respect. This will go a long way in alleviating the water shortage situation in most Indian cities and towns.