Rain water Harvesting and Ground water recharge


A Human being can survive only up to 5 days without water, but can go on for many days without food. Regardless of water content, all parts of the body need water to work properly. Not just humans, every living being including plants need water to survive.


Human body

Up to 60% of the human adult body is water.

Body part                   Water percentage
Brain.                           80–85%
Kidneys                       80–85%
Heart                           75–80%
Lungs                          75–80%
Muscles.                     70–75%
Liver                            70–75%
Skin                             70–75%
Blood                          50%
Bones                         20–25%
Teeth                          8–10%


Fresh water

About 71 percent of the Earth’s surface is covered in water, the oceans hold about 96.5 percent of all Earth’s water the rest is in air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers of the 96.5% water, 97.5% is salt water and 2.5% fresh water. Of the fresh water, only 0.3% is in liquid form on the surface.



How is rain formed?

Drops of water that fall from the sky is rain. Within a cloud, water droplets condense onto one another, causing the droplets to grow. When these water droplets get too heavy to stay suspended in the cloud, they fall to Earth as rain. Water vapor turns into clouds when it cools and condense that turns into liquid water or ice.


What is rain water harvesting?

Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or a reservoir with percolation, so that it seeps down and restores the ground water.

Rainwater harvesting is one of the simplest and oldest methods of self-supply of water for households, and residential and household-scale projects.

In simple terms, it is catching of rain water and using it during non-rainy seasons.


Ground water recharge and its importance?

Soil acts like a sponge. It retains lots of water. We dig borewells to extract water from earth. The more we extract, the deeper we need to go to find water, thereby draining soil of all the water content making us dig deeper and deeper, until we can't find any water. Thereby making our surroundings dry, ultimately leading to desertification.

Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to ground water. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and is often expressed as a flux to the water table surface. Recharge occurs both naturally (through the water cycle) and through anthropogenic processes (i.e., "artificial groundwater recharge"), where rainwater and reclaimed water is routed to the subsurface.

Typically, rain water overflow is diverted to the borewell where recharge of ground water is possible without much effort or expenses, pit is dug around the borewell measuring 5 feet by 5 feet with a depth up to 10 feet depending on the depth of the borewell and the surrounding soil formation, a retaining wall is built and filled with different composition of gravel and sand as per this diagram.


Importance of rainwater harvesting and ground water recharge:

  • Less wastage of fresh water. (Run offs into the ocean)
  • Recharging ground water eliminates the need to dig deeper for extracting water, thereby reducing the cost of extracting water.
  • Plants and trees grow in abundance making our surroundings green and cool, also helps in rain formation.
  • Cools the core of the earth reducing instances of natural calamities like earthquakes, volcanoes, heat waves and other extreme weather conditions.
  • We will have abundance of water for the future generation.

Hence it is most important to save fresh water.


Article By:

Ugender Sathyendranath