Rain Water Harvesting

By
Er. Raj Kumar Aggarwal
Executive Engineer
Baba Farid University of Health Sciences, Faridkot

India, the second largest population in the world, with over 600 million people is facing a water crisis as per
report “NitiAyog”.The level of underground water has gone below the desired limits or has become unfit for human consumption.18 blocks of Punjab has been declared ‘dark zone’ as the ground water extraction is 200% more than the recharge. The ground water is depleting at a higher rate than its replenishment.It is not the level of ground water that is alarming but the speed with which it is going down that needs to be addressed immediately according to experts of Central Ground Water Board.

Rain water harvesting is the only solution for this as it can help to recharge ground water level and can ensure the availability of water in dark or scarce zones.By adopting rain harvesting we can reduce the consumption of water by 40% per head and can also improves the quality of underground water through a process called dilution during recharge.

The harvesting of rain water simply involves the collection of rainwater from roofs/catchment area on which it falls and subsequently saving this water for future use or to recharge the underground water with the help of borewell. The catchment area is the surface area which directly receives the rainfall and provides water to the system for storage or recharge the underground water.

A rain water harvesting system consists of roof /catchment area, down pipes, gutters, rainwater drains, filter, desilting chamber, storage tanks and ground water recharge structures like pits, trench and bore well.

Rain is a gift from nature, when it rains the water pours off the rooftop is carried through G.I.(Galvanized Iron) or PVC (plastic pipes) to the ground level for storage or into the ground borewell to recharge the underground water. Rain water collected in to the storage tanks can be pumped back to tanks placed on the roof to supply the water. It is better to have a tank of 2000 ltr. or less capacity for a roof of 100 sqm area.To prevent evaporation and mosquito breeding, the cover of storage tanks are fitted tightly.

          Good quality water is becoming scarce in thickly populated urban areas day by day.Rain water is soft and free from harmful chemicals which makes it ideal for household consumption and irrigation purposes. So we should value the importance of this natural resource and must save it for future use. It not only meets the demand of water supply during scarce time but also checks surface runoff of water and reduces soil erosion and finally helps to maintain environment.

            According to Punjab Urban Planning and development buildings rules 2017, all houses having areas above 250 sqm and all commercial/ industrial buildings above 100 sqm area should have rain water harvesting structures for both storage and reuse of rain water.

Since the rain water harvesting technology is beneficial, sustainable, easy & eco-friendly method and does not have any harmful effect on the environment.Therefore adoption of rain water harvesting would certainly lead to reduction of many problems related to scarcity of water and to raise the depleting level of underground water.