Rainwater Harvesting

Rainwater Harvesting

1. Technique of collecting and storing rainwater for future use.
2. Traditional method of storing rainwater in underground tanks, ponds, lakes, and check dams.
3. Main purpose is to make the rainwater percolate under the ground to recharge the groundwater level.

Methods of Rainwater Harvesting

1. Rooftop Rainwater Harvesting:
   • Rooftops are excellent rain catchers.
   • Rainwater that falls on the roof of houses, apartments, commercial buildings, etc., is collected and stored in surface tanks.
   • Can be used for domestic purposes.
2. Recharge Pit:
   • Rainwater is first collected from rooftops or open spaces.
   • Directed into percolation pits through pipes for filtration.
   • After filtration, the rainwater enters the recharge pits or ground wells.

People living in rural areas adopt a variety of water collecting methods to capture and store rain water. Some of the methods used are:

(i) Digging of tanks or lakes (Eris):

1. It is one of the traditional water harvesting system in Tamil Nadu.
2. Eris are constructed in such a way that if the water in one eri overflows, it automatically gets diverted to the eri of the next village, as these eris are interconnected.

(ii) Ooranis:

1. These are small ponds to collect rainwater.
2. The water is used for various domestic purposes (drinking, washing, and bathing).
3. These ponds cater the nearby villages.

Advantages of rainwater harvesting:

Rainwater harvesting helps to

• (i) Overcome the rapid depletion of groundwater levels.
• (ii) To Meet the increased demand for water.
• (iii) Reduces flood and soil erosion.
• (iv) Water stored in ground is not contaminated by human and animal wastes and hence can be used for drinking purpose.

More to Know:

Kallanai Dam, also known as Grand Anicut,

1. is the fourth oldest dam in the world,
2. constructed by King Karikala Chola of the Chola Dynasty in the 2nd century A.D. (CE).
3. It still serves the people of Tamilnadu,
4. The dam is located on the River Kaveri, approximately 20 km from the city of Tiruchirapalli.