Rainwater Harvesting Practices

There are two main practices of rainwater harvesting:

1. Storage of rainwater on surface for future use. It is a traditional practice and structures used are underground tanks, ponds, check dams, weirs, etc.

2. Recharge of groundwater. It is a new concept of rainwater harvesting and the structures

generally used are: (a) Pits-recharge:	Pits are constructed for recharging the shallow aquifers.
(b) Trenches:	These are constructed when the permeable strata is available at shallow depths.
(c) Dug wells:	Drainpipes carry the water to a filtration tank from which it flows into the dug well. Rainwater that is collected on rooftop of buildings is also diverted to the dug wells.
(d) Hand pumps:	The existing hand pump may be used for recharging the shallow/deep aquifers, if the availability of water is limited.
(e) Recharge well:	Recharge wells are generally constructed for recharging the deeper aquifers and water is guided through filter media to avoid choking of recharged well.
(f) Recharge shafts:	For recharging the shallow aquifers which are located below clayey surface, recharge shafts are used.
(g) Lateral shafts:	Lateral shafts with bore wells for recharging the upper as well as deeper aquifers.
(h) Spreading techniques:	When permeable strata from top is available, then water

spreading technique is used. Water is spread in streams/nalas by making check-dams, cement plugs or percolation ponds.