PROPERTY & INVESTMENT
The problem is nuanced , however , so let us delve into this a little deeper . The initial number ascribed to the national water resource was over 53 billion cubic metres ( BCM ) per annum . That number represents all the flow in all the rivers . It was this number that gave us the 98 % allocation noted above . That number has subsequently been revised downwards , in part because of changes in rainfall patterns , but also in part because the instrumentation used to measure streamflow has been damaged or destroyed . This process of revision has shown that we now have a similar capacity to gauge rainfall and measure streamflow in rivers as we had in the 1920s . There was a dramatic loss of gauging capacity in 1994 , when 25 % of all systems were lost , never to be recovered . This means that we are flying
blind , with decision-making around things like flood management increasingly impacted by the loss of data management capabilities .
To close the knowledge gaps , the Water Research Commission ( WRC ) commissioned a high-confidence study conducted by the University of Cape Town . The results were published around 2018 , showing the loss of data capture and management capacity shown above , but also revealing a new phenomenon unknown until that report . When subjecting all known rainfall to a sophisticated set of statistical analytics , two new patterns were detected .
The first was about changes to the actual volume of rain , with a clear watershed in 1982 . Before 1982 , South Africa was wetter , and after that date it became drier . This seems counterintuitive given that many of our dams are currently full , but this is what the empirical data shows us . More alarmingly , there is a shift in the seasonal distribution of rainfall , with winter-rainfall areas most notably affected . We can interpret this data , considering the recent flooding , by saying that the data shown in this graphic does not indicate the intensity of the storm events , only the distribution . Stated differently , disturbances to our climate are resulting in heavier than normal rainfall in single events , punctuated by longer periods of dry conditions .
14 I N F R A S T R U C T U R E