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.