Harvesting Rain – Kerala’s Answer to the Water Problem

Kerala’s answer to the water problemRain is the primary source of water on our planet. Rivers, lakes and wells are all secondary sources- yet we depend mainly on these secondary sources to meet our water requirements. Kerala is bountifully blessed by Nature with an annual rainfall of 3100 mm, numerous water bodies and 44 rivers. Since the state lies along the Arabian Sea, it is the first state in India to receive the monsoon rains that fall twice per year, from the southwest and the northeast. However, these rains were never really harvested which often led to flooding and run off. As a result, the water table has been depleted and water shortage is a common problem during summer. The state has tackled this challenge head on by promoting rainwater harvesting. What exactly is rainwater harvesting? It means capturing rain water where it falls, and storing it for reuse after taking adequate measures to ensure that it is clean and non-polluted. Rainwater harvesting is an eco-friendly and economical alternative to meet the ever-increasing demand for water, both for domestic and industrial use.
Simple and EffectiveConstructing a rainwater harvesting system is simple. A catchment area is needed, and this is usually the roof of a building. A filtration system is the next step and this is a chamber filled with fibre, coarse sand or layers of gravel that will filter the rain water. The final requirements are pipelines and a storage tank. The water collected in the storage tanks can be used for all domestic purposes, and made drinkable by purification. On a building with a flat impermeable terrace area of 100 sq metres, in an area where the average rainfall is around 600mm per year, around 36,000 litres of water can be collected per year, even if only 60 % of the total rainfall is harvested. This is about twice the annual drinking water requirement of a five member family.
The Larger PictureRainwater harvesting need not be limited to buildings with storage tanks. For industrial areas and commercial buildings, the alternative to storage tanks is to dig a large catchment area and line it with suitable materials to prevent the water from seeping back into the ground. The tank can also double as an artificial lake, adding to the beauty of the surroundings. The run offs from local catchments can also be stored in open tanks. Seasonal floodwaters from local streams can be harvested and stored too. Conservation of water through watershed management is another important method of rain water harvesting. A watershed is the area of land that drains or sheds water into a specific receiving water body, such as a lake or a river. Kerala is working out ways to best protect and improve the water quality and other natural resources in a watershed. Awareness of the importance of conserving our water resources is increasing, and the popularity of all these methods of water harvesting is also on the rise. Green Kerala is truly making every effort to conserve water, protect nature…and keep the land forever green.