South Africa: How Severe Is the Drought? a Detailed Look At the Data

Facts are few, opinions plenty, on the cause of the water crisis Editor’s summary Piotr Wolski, a water scientist at UCT, has used the latest rainfall and best available weather station data to compare the current drought to past ones.
There is a drought, of course.
But there are also other reasons brought up in the public discourse, particularly on social media, such as population and water demand growth, unreported agricultural use, invasive species sucking out water in catchments, poor planning and mismanagement of water supply system, and lack of foresight in development of new water sources.
It appears that nine stations have data available for recent years, but four are located in the region of the WCWSS dams, and have no significant gaps or systematic errors from 1981 through 2017.
If available SAWS data are screened in a similar manner as the DWS data were (i.e. for continuity and consistency of record), we get five stations with data covering the period 1933 to 2017.
This is how plots for this station look: Again, the 2017 rainfall for that station, and importantly the mean of 3-years prior to 2017 were lower than in any period experienced by this station since 1920.
So the long-term SAWS data from the WCWSS dams region shows that 2017 and the period 2015 to 2017 were the driest since 1933.
The drought, as manifested by rainfall in the region of WCWSS dams, is indeed very rare, and very severe.
Importantly, the analyses reveal that the drought was likely less severe in the coastal plains and in Cape Town itself.
In summary – the analyses presented above, based on the best rainfall data available at this time, show that the drought, manifested through low rainfall in 2015 to 2017, was very rare and severe.

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