Life in our time of cholera?

I love to read, so I’m not proud to admit right upfront that everything I know about “Love in the time of cholera” I learnt in 3 minutes from wikipedia starting about 3 minutes ago. Seems like a book I should read.

But another than playing on the well known book and movie title, this post has nothing to do with the book.

It has everything to do with cholera. And the very real possibility of a cholera or similar disease outbreak in Cape Town in the next year. Here is a little superficial analysis of the numbers.

The City of Cape Town now expects us to run out of municipal water

The City of Cape Town has gone from claiming unequivocally:

“we want to give the people of Cape Town an assurance that this well-run city will not run out of water.”

on the 17th of August 107 to 4 October 2017’s:

If consumption is not reduced to the required levels of 500-million litres of collective usage per day, we are looking at about March 2018 when supply of municipal water would not be available.

How are dam levels and consumption point away from achieving these targets

CT has been stuck persistently above 600Ml (million litres) per day for an extended period and this is down from a peak of 1,200Ml per day in January 2015. The low hanging fruit are long gone. I do not see how we will decrease consumption by another 20% (since we’re over 600Ml at the moment) and this therefore suggests we will run out of water.

Consumption has reduced significantly, but shows no signs of decreasing below 600Ml per day

The increased awareness may prevent an increase in consumption from October to January, but we have yet to see whether this will be contained. It has been evident in every prior year. To me the question isn’t whether we get down to 500Ml in time, or ever, or how close we get even, it’s whether we manage to simply not increase consumption above 618Ml from the last week.

Multi year decline in dam levels
Multi year decline in dam levels

This graph shows the multi-year extent of the problem.

  • Several dry years in a row have resulted in declining dam levels.
  • Peak to trough is between 50% and 40% (lower more recently as water saving measures have had an effect.)
  • Peak is usually September / October each year. So right now basically.
  • We are currently below 40% capacity.
  • We are regularly told that the last 10% is extremely difficult to use, so probably somewhere between 30% and 35% useable water left.

So there we have it. We should expect to use about 40% of capacity and we have between 30% and 35% available.

This is why many people have been saying, while the CoCT has been denying, that we are more likely than not to run out of water. It seems clear that at a mininum we will face water interruptions. At the margin, the interrupted washing loads (and restarting of cycles) and storage of municipal water as emergency preparation may even contribute to increased consumption.

Will people die?

Most people worry first about drinking water. This is appropriate. But drinking water will not be the problem as that volume of water can be managed in a variety of ways.

Start thinking about your ability to flush your toilet.

Cholera can kill within 24 hours. The CoCT, to their credit, plan to keep water running in informal settlements / densely populated areas etc.  I.e. trying to maintian sanitaiton and hygiene in the areas least well prepared to deal with it. I am waiting on complaints about this, but it is absolutely the right move. Help should be focussed on those least able (economically and service infrastructure and possibly education and certainly in terms of access to healthcare services) to help themselves.

There is an oral cholera vaccine now available – of course cholera is just the most infamous of likely diseases.

This may be an extreme outcome, but it feels like it should have moved from place 100 on a city wide risk register to top ten. And that is not something I would have expected even a year ago.

We will also have to see how economic activity is interrupted and what the knock on impact of that is.

It’s going to be an interesting few months.


Published by David Kirk

The opinions expressed on this site are those of the author and other commenters and are not necessarily those of his employer or any other organisation. David Kirk runs Milliman’s actuarial consulting practice in Africa. He is an actuary and is the creator of New Business Margin on Revenue. He specialises in risk and capital management, regulatory change and insurance strategy . He also has extensive experience in embedded value reporting, insurance-related IFRS and share option valuation.

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