RAIN WATER HARVESTING

What is Rainwater harvesting?

Rainwater harvesting is the collection and storage of rain from roofs or from a surface catchments for future use. The water is generally stored in rainwater tanks or directed into mechanisms which recharge ground water. This is appropriate in many parts of the world, such as western Britain, China, Brazil, Thailand, Sri Lanka, Germany and India, where there is enough rain for collection and conventional water resources either do not exist or are at risk of being over-used to supply a large population. Rainwater harvesting can provide lifeline water for human consumption, reduce water bills and the need to build reservoirs which may require the use of valuable land.

Why harvest Rainwater?

India with rivers running through its landscape, receives the highest rainfall among the countries of similar size. But the alarming fact that faces us today is that the rivers are drying up and getting polluted. Some rivers like Yamuna and Saraswati have almost disappeared off the face of India. India –which has 16 per cent of the world’s population, 2.45 per cent of the world’s land area and 4 per cent of the world’s water resources already has a grave drinking water crisis

Estimates of the Central Ground Water Board are that the reservoir of underground water will dry up entirely by 2025 in as many as fifteen States in India – if the present level of exploitation and misuse of underground water continues. By 2050, when more than 50 per cent of the Indian population is expected to shift to the cities, fresh drinking water is expected to get very scarce. The inter-state feuds about the distribution of water are already a big issue in India. Rainwater harvesting takes a very crucial role in this scenario, the conservation and utilization of rain water is of utmost importance today.

The benefits of Rainwater harvesting?

Rainwater harvesting in urban areas can have manifold reasons. To provide supplemental water for the city's requirement, to increase soil moisture levels for urban greenery, to increase the ground water table through artificial recharge, to mitigate urban flooding and to improve the quality of groundwater.. In urban areas of the developed world, at a household level, harvested rainwater can be used for flushing toilets and washing laundry. It can also be used for showering or bathing. It may require treatment prior to use for drinking.

Traditionally, rainwater harvesting has been practised in arid and semi-arid areas, and has provided drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. This method may have been used extensively by the Indus Valley Civilization.

How to harvest rainwater?

Due to inadequate awareness or lack of planning, excess rainfall water has been gets discharged into the oceans after coursing its way through the drains and rivers. It is possible to prevent this wastage of water by storing it during the rainy season — for use during the dry seasons. Alternatively it can also be allowed to seep underground in the dry areas as a measure of maintaining adequate levels of ground water. This water can subsequently be ‘recharged’ or pumped up for irrigational or drinking water purposes.

There are different ways in which rainwater can be harvested. There is a method of what is known as ‘rooftop harvesting’ in which the rainwater is allowed to get collected in built-up tanks. This water can be used for direct consumption as also for recharging groundwater through simple filtration devices. Water can also be collected in tanks that have cement slabs built at their base to prevent the water from seeping underground. This method is usually employed in the desert areas of Rajasthan which often face drinking water problem.

An effort of a large scale begins only on an individual level, each one of us can make a big difference by saving that one drop that will fill an ocean.