What is water harvesting? How can this technique help in the conservation of water?

(N/A) Water harvesting is a technique of capturing and storing rainwater where it falls,rather than allowing it to run off.
This technique helps in the conservation of water in the following ways:
$1$. It recharges groundwater levels,which helps in maintaining the water table.
$2$. Stored water remains unpolluted and can be used for various purposes.
$3$. It provides moisture for vegetation over a wide area,reducing soil erosion and promoting plant growth.