WATER SCARCITY IN SOUTHERN AFRICA

Southern Africa is a water scarce region.  However there are certain factors that make the situation more serious and thus very vulnerable to any chance in climate that affects rainfall.
 
Rainfall:   On average rainfall is low, however this is made worse by geographical factors and high levels of evaporation.  Only 10% of rainfall eventually ends up in rivers.  In Europe 35% of rainfall ends up in rivers and in USA 45%.
 
Urban Centres:  Most urban centres in Southern Africa were built for mines (eg Johannesburg, Pretoria, Windhoek, Harare).  They are situated close to major watershed divides (so the water flows away from the city).  This is very different from the rest of the world, where most major centres of development are located on rivers, lakes or the seashore.  These centres are far from groundwater and are dependent on dams and pipelines.  Water often needs to be transferred from one water “basin” to another.
 
Sewage:  These major centres of development are located upstream of their water storage infrastructure, or crudely put, their sewage flows naturally into their drinking and industrial process-water.  We have reached the point where our developmental demands are outstripping our capacity to supply water at the necessary quality.
 
Industrial water pollution:   Historically it is not water scarcity that has threatened major irrigation-based civilizations, but rather a salts build-up.  The critical risk that needs to be managed is the build-up of salts, nutrients, heavy-metals, endocrine disruptors, carcinogens and radioactivity in rivers arising from the unregulated use of that water for industrial activities such as mining, industry and commercial farming.
 
Unregulated mine closures:   Mine closure is associated with uncontrolled flow of water from the mine void.  This water is highly contaminated, with a low pH (acidic) and a high sulphate content, also containing a complex cocktail of heavy metals and radionuclides.  This is known as Acid Mine Drainage.
 
Urbanization and Population Growth:   Infrastructure investment in dams and pipes is being outstripped by demand, or is stunted as a result of insufficient investment in maintenance.
Dr Anthony Turton: the State of Water in Southern Africa.