(II) Recharge of ground water
The structures used for recharge of ground water are:
(a) Hand Pumps:
The water should pass through a filter bed before percolation in existing hand pumps. They are used for recharging aquifiers.
They are (1-2) m wide and 3 m deep. They are also back filled with gravels and coarse sand to aid filtration before percolation to the ground. They are used for recharging a shallow aquifer.
(c) Dug wells:
The rain water, after filtration, is put into existing dug wells for storage.
(d) Rooftop and road rop collection of rainwater:
In urban areas, these methods are very useful to recharge aquifers.