Wednesday, May 20, 2020

Rain water harvesting

  • The first question one has in his mind after reading the title that what is rain water harvesting. It is a technique for accumulation and storage of rain water which gets run off. By storing that water we are able to use that water for our purposes. 
  • Next question that one has why to do so. As we know water is an important resource but because of many reasons like our increasing population and increasing demand has deemed this resource and we need water every bit of a second. Thus, rain water harvesting should become an important part of our life style.
  • Now how to do this. There are several techniques. At our home level we can use the most common technique that is roof top harvesting. The image given below gives idea about the technique: 
  • Another technique better than the previously described is rainsaucer system. In this technique you can use a upside down umbrella like object to accumulate rain water. Advantage of this technique is it decreases the potential of contamination and makes the water much usable for potable purposes. Such approach is used by developing countries now a days.

  • Another common technique is building a underground tank or reservoir for storing water.
  • Some methods involve collection of surface run off. This can be done by checkdams, field pit and through ponds and reservoirs. 
  • Checkdam: it is a low height weir constructed across a small stream to prevent the water from flowing and to accumulate water. Such water infiltrates into the ground and helps in improving groundwater quantity in the area. In Saurashtra of Gujarat, depending on local geological conditions these check dams have prooved beneficial for increasing ground water quantity.
  • Field pit: as the name indicates  a small pit is prepared in the field and the water which gets stored is utilized for crops when water is not available. This method increases irrigation capacity by artificial recharge and by raising up water table.
  • Ponds and reservior: such ponds are constructed before monsoon and capacity of such ponds are increases by desilting activities. Desilting means removal of the material like clay and silt for widening the pond. Desilting can be done manually as well as by machinaries like power shovel, dragline etc.