Mention the two advantages of rain harvesting?

Hint:
Two methods of water harvesting in India:
  (i) The excess water collected through rainfall can be carried to the wells, which further helps to recharge the wells and underground water.

  (ii) Collection of rainwater on top of the roof and directing dry tanks.

Complete solution:
Rainwater harvesting (RWH) is the collection and storage of rain, rather than closing it. Rainwater is collected from the roof-like surface and redirected to a reservoir with a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or orifice. Dew and fog can also be collected with traps or other equipment. Rainwater harvesting differs from stormwater harvesting, as runoff is collected from roofs rather than from roofs, drains, roads, or any other land surfaces. Its uses include watering gardens, livestock, irrigation, domestic use with proper treatment and domestic heating. Harvested water may also be committed to prolonged storage or groundwater recharge.

Rainwater harvesting is one of the simplest and oldest methods of self-supply of water for households, and residential and household-scale projects are usually funded by the user. However, large systems for schools, hospitals, and other facilities may only be able to finance costs by companies, organizations and government units.

Advantages -
Rainwater harvesting provides an independent water supply during regional water restrictions and in developed countries, it is often used to supplement the main supply. It provides water when drought occurs, which can help reduce flooding in low-lying areas and reduce demand on wells that may be able to maintain groundwater levels. It also helps in the availability of potable water, as rainwater is largely free from salinity and other salts. Applications of rainwater harvesting in urban water systems by reducing the need for clean water in water distribution systems, less generated stormwater in sewer systems, [4] and water supply and waste in freshwater bodies that reduce stormwater pollution Provide substantial benefits for water sub-systems.

  A large body of work has focused on life cycle assessment and the development of its costing method to assess environmental impacts and funding levels that can be avoided by implementing rainwater harvesting systems.

Note:
Rainwater harvesting is a widely used method of storing rainwater in countries presenting with drought characteristics. Several pieces of research have obtained and developed various criteria and techniques to select suitable sites for rainwater harvesting. Some research was identified and suitable sites were selected for possible construction of dams, as well as a model builder in Archapel. The model added several parameters such as slope, runoff capacity, land cover/use, stream order, soil quality, and hydrology to determine the suitability of the site for rainwater harvesting.