For many decades rain water has been one of the least recognized sources of water in world yet largely in abundance in many different parts of the world. In many parts of the world people move long distances looking for water which even in most cases is dirty and contaminated. This is mainly due to the fact little effort has been put in tapping this abundant source. Every year over 10000mm of rainfall is received but a lot of it flows away as runoff while little amount is used for human activities.
Falling rain can provide some of the cleanest naturally occurring water that is available anywhere. This is not surprising, as it is a result of a natural distillation process that is at risk only from airborne particles and from man-made pollution caused by the smoke and ash of fires and industrial processes, particularly those which burn fossil fuels. It is evident, therefore, that there is considerable scope for the collection of rainwater when it falls, before huge losses occur due to evaporation and transpiration and before it becomes contaminated by natural means or man-made activities. (Water Aid, technical brief)
Rain water is useful in a number of ways which include:
- Recharging ground water
- Agricultural uses like feeding animals, irrigation etc
- Human consumption like drinking, washing etc
The mentioned uses above are only a few of the importance of this free and abundant source of water. The harvesting of rainwater as compared to other sources of water is the most cost effective. This is so because rainwater collecting materials like containers are cheap and affordable. The other reason is that it provides a supply of safe water close to homes, schools or clinics, encourages increased consumption, reduces the time women and children spend collecting water, reduces back strain or injuries from carrying heavy water containers. Collected rainwater can also be consumed without treatment provided a clean collecting surface has been used.
Although rainfall is associated with disadvantages like contamination from the collecting surface, if fully utilized and well harvested, it can help to tackle the water problem that exist in the world today.