Water and Health

Abstract

There is plenty of rainfall in the world—in fact, if fairly divided amongst the world population we would all have around 28,4.00 litres per day★ each.1 However, rainfall is not uniform and does not necessarily fall where we want it to. Almost all communities live where there is access to fresh drinking water, and this usually means areas in which the rainfall is at least 250 to 400 mm per year (10 to 15 inches). The few exceptions to this are in desert areas where there are perennial rivers—for example, the Egyptian Nile. Where rainfall is seasonal there will be a storage requirement, also a transport need. For lifting from rivers and lakes, low lift pumps are used. If the water source is subterranean then bore holes and high-lift pumps will be needed. In the West we believe that water is something that comes out of a tap with unfailing regularity, but in the developing countries water supplies are a major concern and their provision is essential to the development process.