Rainwater Harvesting: ‘Catching and Storing Rain where it falls’. It is a simple technique of catching rainwater and storing it in underground aquifers – natural or man-made. Rainwater can be stored in tanks and then used for drinking and cooking – as it is done in the desert areas of Rajasthan or it can be done to replenish the groundwater so that the dug wells/tube wells in the area keep on yielding water – as it is usually done in urban centers.
Rainwater Harvesting helps increase the water table, improve the quality of groundwater, reduce water logging and reduce tube well pumping costs. It is ideal for places with water scarcity and no readily available source of surface water supply.
For ‘Artificial Recharge to groundwater through Bore wells / Dug wells – Rainwater collected from the rooftop of a building is diverted by drainpipes to a Recharge structure. An efficient rainwater harvesting structure should be able to direct clean rainwater runoff to the groundwater in the active aquifer of the area and should have the capacity to hold at least the runoff generated in one hour of high intensity rainfall.
If the water table in your area is below 8 m below ground level then you must do rainwater harvesting.
To calculate the size of the rainwater harvesting structure appropriate for your area, the following guidelines (based on Central Groundwater Board recommendations) may be referred to:
The depth of the borewell may be decided based on the depth and thickness of the weathered formation / granular zone (receptive to water) and should always be kept above the post monsoon water level. Abandoned / dried borewells can also be used for recharge.
