Rainwater harvesting is a simple method by which rainfall is collected for future usage. In other words, collected rain water can be utilized for different purposes or can be collected and kept in a safe place for later use.
Garden, agricultural and personal use of collected rain water are some of its many applications. Rainwater collected from a rain gutter may be used for flushing toilets.
Collected rain water can also be used to create non-potable water for washing floors, watering trees and vegetation in the garden, cleaning driveways etc.
Tamil Nadu is the first state in India which has made rooftop rainwater harvesting structure compulsory to all the houses across the state. There are legal provisions to punish the defaulters.
Different methods have been adopted in different areas for Rain Water Harvesting.
- In hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kms’ of the Western Himalayas for agriculture.
- “Rooftop rainwater harvesting” is commonly practised to store drinking water, particularly in Rajasthan.
- In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
- In arid and semi-arid regions, agricultural fields were converted into rain-fed storage structures that allowed the water to stand and moisten the soil such as ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.
- The tankas are part of the well-developed rooftop rainwater harvesting system and are built inside the main house or the courtyard. This is mainly practised in Rajasthan, particularly in Bikaner, Phalodi and Barmer areas for saving the rainwater. Many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool.
