If we explain in simple words, Rainwater harvesting is nothing but storing or accumulating rainwater for future usage during scarcity. People call it a rain collection system, rain catchment system, rainwater collection tank, rainwater conservation system, etc. People in India are practicing rainwater harvesting since the 10th century. In the 11th century, the largest rainwater harvesting tank was created by Chola kings and it is 16 kilometres long. Rainwater harvesting is a cost-effective solution to bridge the gap between water availability and demand. How it works, we will read it in this blog. You must have heard of nadi, baoli, kund, taanka, bawari, etc. these all were the rainwater conservation systems of ancient India. Some people think water is limitless on the earth however fresh usable water is available in limited quantity and it’s declining day by day. These days because of Growing population, industries, and agricultural land have made moreusage ofwater. We need to think about a variety of waste to save and conserve our water resources. We have to understand, No water no life. It is as simple as that.
Rainwater harvesting in India
In India, rainwater harvesting has been in practice for more than 4000 years and Indians are called a great rainwater harvester. Rainwater harvesting is one of the most effective methods of water management and water conservation. Rainwater is the only major source of India’s water need. Despite this fact, its collection and significance are highly neglected in India. On average, India receives around 1170 mm rainfall in a year out of which, 80 – 90% is received only during monsoons. Rainwater harvesting is the collection and storage of rainwater in deep pits or reservoirs to be used later in summer. Many states, such as Maharashtra, Rajasthan were hit by a severe drought and drinking water had to be transported through ‘water trains’. Rainwater collection is needed in India.
Importance of rain water harvesting – The need& benefits
Benefit
- Rainwater is a relatively clean and absolutely free source of water
- You have total control over your water supply (ideal for cities with water restrictions)
- It is socially acceptable and environmentally responsible
- It promotes self-sufficiency and helps conserve water
- Rainwater is better for landscape plants and gardens because it is not chlorinated
- It reduces stormwater runoff from homes and businesses
- It can solve the drainage problems on your property while providing you with free water
- It uses simple technologies that are inexpensive and easy to maintain
- It can be used as a main source of water or as a backup source to wells and municipal water
- The system can be easily retrofitted to an existing structure or built during new home construction
- System are very flexible and can be modular in nature, allowing expansion, reconfiguration, or relocation, if necessary
- It can provide an excellent back-up source of water for emergencies
Need
- To arrest decline in ground water levels.
- To overcome the inadequacy of surface water to meet our demands.
- To enhance availability of ground water at specific place and time and utilize rain water for sustainable development.
- To increase infiltration of rain water in the subsoil this has decreased drastically in urban areas due to paving of open area.
- To improve ground water quality by dilution.
- To increase agriculture production.
- To improve ecology of the area by increase in vegetation cover etc.
Advantages
- The cost of recharge to sub-surface reservoir is lower than surface reservoirs.
- The aquifer serves as a distribution system also.
- No land is wasted for storage purpose and no population displacement is involved.
- Ground water is not directly exposed to evaporation and pollution.
- Storing water under ground is environment friendly.
- It increases the productivity of aquifer.
- It reduces flood hazards.
- Effects rise in ground water levels.
- Mitigates effects of drought.
- Reduces soil erosion.
Method of rain water harvesting?
Urban Areas:
Roof top rain water/storm runoff harvesting through
(i) Recharge Pit
(ii) Recharge Trench
(iii) Tubewell
(iv) Recharge Well
Rural Areas:
Rain water harvesting through
(i) Gully Plug
(ii) Contour Bund
(iii) Gabion Structure
(iv) Percolation Tank
(v) Check Dam/Cement Plug/Nala Bund
(vi) Recharge Shaft
(vii) Dugwell Recharge
Rain water harvesting cost in India
It varies state to state as per online research 4.5 lakh to harvest more than 170 million litres of water annually. Rainwater harvesting methods are site specific and hence it is difficult to give a generalised cost.
People or organizations availing the scheme were to be provided with subsidy ranging upto Rs 2.5 lakh. The department even launched an annual award for the best rainwater harvesting practice to promote the scheme.
Disclaimer: For precise details you need to get in touch with government officials. Rainwater collection systemcost details available on the basis of online research.