Rainwater Harvesting

A sufficient, clean drinking water supply is essential to life. Millions of people throughout the world still do not have access to this basic necessity. Moreover the groundwater as a dependable source and its increased use for various uses has is always reflected in the drastic lowering of water levels and subsequent disappearance of water locally cannot be ruled out, since the efficacy of surface water bodies (tanks, lakes and canals etc.) for recharging to the ground water has reduced drastically for simple reason that the local water levels are too deep to recharge. Today Even after decades of work by governments and NGOs to bring potable water to the poorer people of the world, the situation is still severe. Water problem has different reasons for different people and different areas but in general, when we say water problem we refer to the access of water to the poor people since they cannot afford water supply systems available for money, which are not scarce. We need to come up with an idea that works effectively and viable for poor too. Apparently Rainwater harvesting (not a noble idea though!) is an option that has been adopted in many areas of the world where conventional water supply systems have failed to meet people’s needs. It is a technique that has been used since the beginning of civilization. Today, all we need to do is to promote the idea and make the information available to poor around the world.

Rainwater is often used for drinking and cooking and so it is vital that the highest possible standards are met. Rainwater, unfortunately, often does not meet the World Health Organization water quality guidelines. This does not mean that the water is unsafe to drink. It is lot better than most of the resources in use. Also treatment of this water makes it absolutely acceptable as potable water. There are several simple methods of treatment for water before drinking.

• Boiling water will kill any harmful bacteria, which may be present.
• Adding chlorine in the right quantity will disinfect the water.
• Slow sand filtration will remove any harmful organisms when carried out properly.
• A recently developed technique called solar disinfections utilizes plastic bottles, which are filled with water and placed in the sun for one full day. The back of the bottle is painted black.

Examples of rainwater harvesting systems can be found in all the great civilizations throughout history. In industrialized countries, sophisticated systems have been developed with the aim of reducing water bills or to meet the needs of remote communities or individual households in arid regions. Traditionally, in Uganda and Sri Lanka, for example, rainwater is collected from trees, using banana leaves or stems as temporary gutters; up to 200 liters may be collected from a large tree in a single storm. Many individuals and groups have taken the initiative and developed a wide variety of these systems throughout the world. It is worth distinguishing, between the various types of systems practiced throughout the world. Rainwater harvesting has come to mean the control or utilization of rainwater close to the point rain reaches the earth.

A question that can be raised is: are we not blocking off run-off water from reaching downstream? There are two explanations possible: One, in most of the villages around the urban area and urban areas, run-off water “goes down the drain” becoming contaminated and useless. Two, the harvestable run off is just a very small percentage of the total rainfall. Thus, there is no question of totally blocking the run-off water nor there is a scope for real upstream-downstream conflicts.

It is worth bearing in mind that rainwater harvesting is not the absolute answer to household water problems. There is a complex set of inter-related circumstances that have to be considered when choosing the appropriate water source. These include cost, climate, hydrology, social and political elements, as well as technology, all play a role in the eventual choice of water supply scheme that is adopted for a given situation. Rainwater harvesting is only one possible choice, but one that is often overlooked by planners, engineers and builders. The reason that rainwater harvesting is rarely considered is often due to lack of information