That moment – when the most essential commodity for the sustenance of the human race becomes the scarcest – water. If facts are anything to go by, 70 percent of our Earth consists of water, out of which only 2.5% is available as fresh water. Even that fresh water is not easily accessible, since a lot of it is trapped in glaciers and ice at the poles. Hence, what we are left with is less than a percent of fresh water.
It’s an alarming situation, with very less hope in sight, if adequate measures are not adhered to. For situations undesired and unwanted, the best and most appropriate solution in sight is Rainwater harvesting.
What is Rainwater Harvesting?
This is a highly effective technique requiring minimum resources with maximum benefits. It is a simple technique where rainwater is collected from the surface of the rooftop and allowed to seep into or stored in a storage tank or underground pits. This water stored could be used when required in the future.
The different types of rain water conservation methods used are –
- Surface run off harvesting: Prevalent in urban areas, where runoffs can be used to recharge aquifers using various techniques.
- Rooftop harvesting: This is where you catch the rainwater where it falls. Here, rooftop is the catchment and rain water is then stored in a tank or an artificial recharge system.
There is one very important aspect in rain water harvesting that needs to be taken care of – Filters. This is of high importance since there is always a doubt if rainwater might contaminate the ground water with certain harmful substances. Filters are basically used to remove turbidity, color, and microorganisms. Different types of filters are used like –
- Gravel filter
- Sand filter
- Netlon mesh filter
- Charcoal filter
Rainwater harvesting around the world
- Singapore: Limited land resources and a rising demand for water is one of the biggest concerns for this urban center. Almost 86% of Singapore’s population lives in high-rise buildings. Light roofing is placed on the roofs to act as catchment. Collected roof water is kept in separate cisterns on the roofs for non-potable uses.
- Tokyo, Japan: Rainwater harvesting is very much prevalent here as to mitigate water shortages, controlling floods and save water for emergencies.
- Berlin, Germany: In October 1998, rainwater utilization systems were introduced in Berlin as part of a large scale urban re-development, the Daimler Chrysler Pots damer Platz, to control urban flooding, save city water and create a better micro climate.
- Thailand: Storing rainwater from rooftop run-off in jars is an appropriate and inexpensive means of obtaining high quality drinking water in Thailand. Prior to this, many communities had no means of protecting drinking water from waste and mosquito infestation.
The biggest and most prominent benefit of rain water harvesting is conservation and easy availability of fresh water for people. This is going to be a highly useful method for the conservation and storage of fresh water for dry continents like Australia, water scarce countries like India, African countries and also many other places around the world. Moreover, for poor countries, storing and using this water would also mean a huge cut down of their water bills.