ENVIS Centre, Ministry of Environment & Forest, Govt. of India

Printed Date: Wednesday, June 19, 2024

Green Lessons

What is Rain Water Harvesting? 

Rain Water Harvesting is collection and storage of rain water that runs off from catchments areas like roofs, pavements, roads, parks, open grounds etc.  This rain water can be collected and stored as surface storage in tanks or can be recharged into the ground water.

Rain water falling on roof tops and other areas and where sufficient space is not available for surface storages, is guided into sub-soil water through various techniques. Structures generally used for this purpose are;

1.      Recharge pits

2.      Recharge trenches

3.      Recharge shafts

4.      Trench with Recharge Bore well

5.      Recharge through existing dug well

6.      Recharge through abandoned tube well, abandoned hand pumps

7.      Percolation tanks etc.


2.     Why harvest rainwater

This is perhaps one of the most frequently asked questions, as to why one should harvest rainwater. There are many reasons but following are some of the important ones.

§  To arrest ground water decline and augment ground water table

§  To beneficiate water quality in aquifers

§  To conserve surface water runoff during monsoon

§  To reduce soil erosion

§  To inculcate a culture of water conservation


3.     How much can we actually save?

A concrete, tiled and paved area of 100 m. sq. size yields about 55 thousand liters of rain water annually; in this case we can save up to 40 thousand liters. The water saved is about four times the annual drinking requirement of a five member family. 


4.     Benefits of Rain Water Harvesting?

       Recharge of ground water through rain water is long continuous process. It is an investment for our next generation. Beside recharge of ground water, rain water harvesting benefits us in many ways like;

1.      Improving the quality of ground water.

2.      Reducing soil erosion as the surface runoff is reduced.

3.      Choking of storm water drains and flooding of roads during monsoon is minimized.


5.     What will be the quality of water? 
You are putting rain water into the ground, which once contaminated, cannot be cleaned easily. Please do not let water with sewage or other dirt flow into your recharge pits. This is why the cleanest rainwater is from our rooftops. There are also filters to keep some dirt out.


6.     Does it require a lot of maintenance? 
Once or twice a year, at very little cost. Remember rainwater harvesting means that you have to get involved. This is about making water all our business. This is about building our relationship with water. With the environment. Harvest rain. Learn the value of each raindrop. 


Other question & answers

What is Ecology?

The study of the relationships between organisms and their environments, including, interactions of living organisms with one another and with their non-living surroundings, the flow of matter and energy in an environment, and the structure and functions of nature.


1.What are the components of environment?

There are two environmental components: Abiotic and Biotic


2. Define Environmental Conservation?

It means protection of living organisms and natural resources from continuous exploitation. It is divided into two categories:

·  In-situ Conservation: The conservation of components of biological diversity within their natural habitats.

·  Ex-situ Conservation: Pertaining to study or maintenance of an organism or groups of organisms away from the place where they naturally occur. Commonly associated with collections of plants and animals in storage facilities, botanic gardens or zoos.


3. Define sustainable development?

Sustainable Development is the development that meets the needs and aspirations of the current generation without compromising the ability to meet those of future generations.

4. What are natural resources?

Natural resources are the raw materials that occur naturally within environments and exist undisturbed in past by human activities


5. What are renewable resources?

These are the natural resources which are replaced by natural processes and there is no danger of a lack of long-term availability. Examples of renewable energy resources are solar radiation, tides, winds and hydroelectricity. Some other resources are wood, paper, and leather.

6. What are non-renewable resources?

These are the natural resources which cannot be produced, re-grown, regenerated, or reused. These resources often exists in a fixed amount (stock) in various places in the earth's crust and has the potential for renewal only by geological, physical, and chemical processes taking place over hundreds of millions to billions of years. Examples of nonrenewable resources are fossil fuel (such as coal, petroleum and natural gas) and nuclear power. In contrast, resources such as timber (when harvested sustainably) or metals (which can be recycled) are considered renewable resources


7. What are fossil fuels?

Fossil fuels are formed due to the partial or complete decomposition of organic material as a result of exposure to heat and pressure in earth's crust over millions of years. e.g. crude oil, natural gas, and coal etc.


8. What is global warming?

The term given to the possibility that Earth's atmosphere is gradually warming because of the greenhouse effect of carbon dioxide and other gases. Global warming is thought by many to be the most serious global environmental issue facing our society


9. What is the difference between climate and weather?

The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time. it is not the same everywhere and includes events humidity, rainfall and temperature. Climate is the average weather pattern in a place over many years.