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Rainwater Harvesting – Definition, Need, Significance, Methods

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Rainwater harvesting refers to the process or technology which is used for the conservation of rainwater through the collection, storing, and purifying of the rainwater which runs off from rooftops, parks, and other uses. The uses of rainwater harvesting range from watering gardens, livestock, irrigation, and domestic uses. The water harvested is used for a longer duration or for groundwater recharge. It is one of the oldest and also simplest methods of self-supply of water for households.

Rainwater Harvesting

Water Harvesting is one of the most normally utilized techniques to save water. It alludes to putting away water for different purposes. The thought behind water collecting is to not squander the water and keep it from running off. All in all, it is finished gathering water utilizing straightforward components. This strategy is exceptionally valuable considering the water shortage that is going on in India. In addition, water gathering is not difficult to such an extent that nearly anybody can make it happen. We should urge this training to assist individuals with gaining admittance to clean water effectively with practically no expense.

How to Harvest Rainwater?

The major components which are essential for rainwater harvesting systems include the following:

  1. Catchment: The catchment is used for the collection and also storage of the captured form of rainwater.
  2. Conveyance system: The transportation of the harvested water from the catchment to the recharge zone is done by this system of conveyance.
  3. Flush: The first spell of rain is flushed out from it.
  4. Filter: The filter portion of the system is used for the collection of rainwater and also the removal of pollutants.
  5. Tanks and Recharge Structure: This is used for the storage of filtered water which is ready to use form.

The process of rainwater harvesting is the collection and also storage of the rainwater, which runs off naturally or from man-made catchment areas like rooftops, compounds, rock surfaces, and so forth.

Many factors play a role in the amount and quality of the rainwater harvested. These factors are as follows:

  • Features of the catchment areas.
  • Availability of the necessary technological advancement.
  • Impact it has on the environment.
  • The capacity of the tanks.
  • Types of roofs used and their material.
  • Frequency, quantity, and quality of rainfall.

Rainwater Harvesting Diagram

Rain water harvesting

Benefits of  Rain Water Harvesting

Importance of Rainwater Harvesting

Water Crisis

The problems of the water crisis, which have been increasing over the years in different parts of the world and India, can be tactfully combated by rainwater harvesting. This is particularly useful in hilly areas, where it can be used for domestic uses, and also in remote areas, where surface pollution is less comparatively and hence rainwater harvesting is ideal.


Rainwater distribution is not equally distributed over space and time, and many of the crops are more water-intensive. Hence, the unavailability of water of equal quality and quantity would cause drastic problems. Hence, rainwater harvesting could help in this process of water unequal distribution.

Bad Monsoon

Bad monsoon or less monsoon can lead to low crop yield and a shortage of food. Even flora and fauna also suffer from the same. Farmers are the most affected group by bad monsoons and rainwater harvesting is the hence ideal solution for the farmers.

Control of Water-borne diseases

If clean water is not available, then the consumption of polluted water will lead to an increase in water-borne diseases.

Alternative for water supply in Dry areas

It can work as a good alternative source of water for the backup of the main supply of water in areas of dry spells and it can be used by the community. It can help in irrigation and also work as a cost-effective method.

Stored for Future Use

Stored rainwater is used for revitalizing ground-level water and also for improving its quality. It also helps to raise the level of groundwater and also tube wells are prevented from drying off. Hence, it helps in checking surface runoff and also reduces incidents of soil erosion.

Methods of Rainwater Harvesting

There are two most commonly used methods of rainwater harvesting. This include:

Surface Runoff Harvesting

This is one of the most suitable forms of rainwater harvesting in urban spaces. This is stored and can be used in the future. The surface runoff rainwater in the forms of ponds, tanks, and reservoirs are built for the purpose of same. Insufficient availability of water can lead to problems in both domestic and also sanitation issues; leading to environmental pollution. This could be prevented by storing surface water and also directing their flow towards small creeks and also streams, into reservoirs.

Rooftop Rainwater Harvesting

Interception of the rainwater in a particular direction is the first requirement. The water should reach a bucket or a tank through pipes. Construction of recharge pits can be done to hold onto the rainwater and rooftop harvesting can be done with the existing tubewells. The filter is placed for purification of the water and its usage.

Advantages of Rainwater Harvesting

The advantages of rainwater harvesting are as follows:

Reduced bills of water supply

Rainwater harvesting is one of the most cost-effective, provisions of high quality, lesser dependence on tube wells and wells, and one of the easiest to maintain systems. The cost of the foundation of rainwater harvesting structures is quite less than other pumping structures.

Benefits in terms of Ecology

It is one of the environment-friendly methods and also minimizes the impacts of floods by rushing water to larger tanks for recycling and helps in the reduction of the pressure on drainage.

Reduces Erosion and Flooding

It reduces the processes of soil erosion and also hazards from the flood by the collection of rainwater and reduces the flow of stormwater for prevention of urban flooding around the buildings.

Adequate for irrigation

Rainwater collection helps to mitigate droughts and since they are mostly free of harmful chemicals and substances, which makes is suitable for irrigation.

Disadvantages of Rainwater Harvesting

With advantages, come some disadvantages of rainwater harvesting. Some of them are mentioned below:

  1. It requires regular maintenance. Otherwise, the purity of the water can be missed out.
  2. Technical skills are required for the installation and working of the mechanism; otherwise, it becomes a little tiresome.
  3. With irregular rainfall in India, it can limit the supply of rainwater.
  4. If the installation is not done in the correct format, it can lead to the breeding of mosquitoes and may increase waterborne diseases.
  5. There is a certain limit for storage of the water, if it exceeds the limit, it can lead to an overflow of water; ultimately affecting the infrastructure around.

Need for Rainwater Harvesting- Today And Future

The need for rainwater harvesting can be as follows:

  1. It helped to meet the demands for an inadequate supply of water from the surface.
  2. It helps to control the decline of show groundwater levels.
  3. They help to increase the water quantity in a specific place and in a given time for sustainable development, which is very important for sustainable development.
  4. It helps to improve the quality of groundwater through the process of dilution.

Examples of Traditional Water Harvesting Systems in India


Water Harvesting Techniques

Trans-Himalayan Region Zing- Tanks that are used to collect water from the melted snows in Ladakh
Western Himalayas

Kul- It is used for the water channels in mountain areas of Jammu, Himachal Pradesh

Naula- It refers to the small ponds in Uttaranchal.

Eastern Himalayas

Apatani System- It refers to the terraced plots which are connected by the inlet and also the outlet channels in the areas of Arunachal Pradesh.

Bamboo Drip System- Water is collected from the streams in the hills which are brought to the plains by bamboo pipes for drip irrigation in Meghalaya.

Brahmaputra Valley

Dongs- Ponds in Assam are referred to as dongs.

Jampois- It refer to the small irrigational channels linking the rice fields to the streams in the Jalpaiguri district.

Indo-Gangetic Plain

Dighis- It refers to the small square or the circular reservoirs fed by the canals from the rivers in Delhi.

Baolis- It refers to the secular structured step-wells.

Thar Desert

Tankas- It refers to the underground tank of Bikaner in Rajasthan.

Kund- It refers to the circular underground well, having saucer-shaped earthen-shaped catchment areas.

Central Highlands Johads- They refer to the earthen shaped check dams in Alwar of Rajasthan.

FAQs on Rainwater Harvesting

Question 1: What is rainwater harvesting?


It refers to the collection and also storage of rain water which runs off from roof tops, parks, open grounds, roads and so on.

Question 2: What is the importance of rainwater harvesting?


Rainwater harvesting helps to reduce soil erosion and floods by collection of the rainwater.

Question 3: What are the factors affecting the amount of rainwater harvested?


Some important factors affecting the amount of rainwater harvested are:

  1. Features of the catchments.
  2. Availability of the technologies.
  3. Capacity of the storage tanks
  4. Types of roofs and their slopes.

Question 4: What are the different methods of rainwater harvesting?


Two important methods of rainwater harvesting are as follows:

  1. Surface runoff harvesting.
  2. Rooftop Rainwater harvesting

Question 5:  What are the components of a rainwater harvesting system?


Some important components of rainwater harvesting system includes:

  • Filter
  • Storage facilitiy
  • Conduits
  • Recharge structures

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Last Updated : 07 Mar, 2023
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