Water Availability - Drought Implications
Rainfall patterns within South Africa is one of great variability. South Africa’s mean annual precipitation is estimated at 450mm compared to the global average of 860mm. Seasonal rainfall percentage deviations since 1960 has shown that the wide fluctuations about the long-term average and it is in this context that large rainfall deficits must be assessed. As an example, between July of 1960 and June of 2004, there have been 8 summer-rainfall seasons where rainfall for the entire summer-rainfall area has been less than 80% of normal. It can be safely assumed that a shortfall of 20% from normal rainfall will cause crop and water shortfalls in many regions accompanied by social and economic hardship.
Current observations still show the persistence of a strong El-Niño. However, most models are confidently showing a gradual decay of El-Niño and the development of a neutral ENSO (El-Niño Southern Oscillation) state towards the winter season (SAWS, 2016). The forecast shows a huge disparity in the rainfall and temperature forecast for the coming seasons, therefore the likelihood of climate conditions for the coming winter season is overshadowed by the growing uncertainty in the forecast. It is very difficult to look at the entire summer-rainfall region and deduce that drought affected all of these areas equally. On the contrary, some of the provinces in South Africa appear to suffer more harshly than others at times of rainfall deficit.
In the Overberg Region, the impact of the drought has been particularly harsh and we have therefore been informed that the Province of the Western Cape has been declared a disaster as a result of the magnitude and severity of drought affecting the Western Cape (Provincial Gazette Extraordinary 7771, dated Wednesday, 24th May 2017). Water Conservation and Demand Management must be a priority during this time especially looking at the state of the major dams supplying the Overberg Water schemes.