Day Zero – The day they turn off the taps in Cape Town.
Some of you may have been wondering what is happening with Day Zero down here in Cape Town since my last post in February?
It hasn’t gone away entirely, but it has been postponed to 2019.
Typically, we get no rain over the summer months, relying on good winter rains to fill up the dams for the following summer. In April this year we got rain about twice; the same for May. When I say ‘rain’ it could be all of 0.1 mm!
But now it is starting to rain a little more often and a little more heavily. We got a whole 1 cm one week and just the other day we got 2 cm in a few days. Hooray!
I am talking about the rainfall in my garden. If we’re lucky it does rain more in other parts of the Cape and hopefully more so in the catchment area, to fill up the dams, as you can see below.
Dam levels and comparisons.
The above graph shows the total dam levels over the course of one year, starting at January, week 1, for a period of ten years (each line is a different year). As you can see where I have indicated, the dam levels for all the years 2009 to 2014 were consistently good.
It is only over the last three years, 2015 to 2017 that the dam levels have dropped significantly, when we did not receive good winter rains.
I’d like to point out here how well Capetonians have been saving water.
If you look at the gradient of the graph from the top left down to the lower points, (week 1 to week 20, this is from January to May/June) the dam levels fall as water is used and there is no rainfall.
You’ll notice that every year follows the same kind of downward slope of about 20 degrees, until you get to this year, 2018, the thick red triangle line. The slope for 2018 is about 10 degrees, which is half as steep.
This is because everyone has made such a great effort to save water.
This is what has kept us from reaching Day Zero so far.
Above you can see how the levels of the dams fluctuate over the years, reaching their lowest points just before the winter rains. You can see that from 2014 to now, the dams have simply not filled up enough, as the winter rains have been so poor.
The above graph shows the levels in each of the major dams from 2014 to the present, for the week beginning June 18th. The last two diagrams are nearly identical as they are just a week apart.
The above diagram shows the same information as the graph, but in percentages. You can see that on this date in 2014 all the dams were still practically full, with the levels steadily decreasing from 2015 to 2017. However, the recent rains have increased the levels this year to such an extent that the dams are now fuller than they were in 2016.
The above graph indicates more than anything just how successful Capetonians have been in saving water.
The yellow area is the critical zone. If water usage fell below this, Day Zero would be implemented. The taps would be turned off and we would have to queue for water at designated areas. The dotted black line shows the actual water usage and by stringently saving water we have kept above the yellow danger zone.
You’ll notice that suddenly in May the dotted black line shoots upwards. This is because it rained.
If – and this is still a big if – we get good rains over the next two months we might avoid Day Zero in 2019.
I think it is unlikely the total dam levels will reach 60%, which would be a safe amount to last us through next dry season (September to April.)
We are still on Level 6 water restrictions: 50 litres of water per person per day.
There are adverts in the papers encouraging people still to stay within these limits.
Toilets in many shopping centres or restaurants have replaced soap in the dispensers with hand sanitiser and the taps have been turned off, so there is no water.
I saw a comment on a YouTube clip about CT and Day Zero where someone thought 50 litres was a lot of water and you could easily live within this.
Well you can live within it, but it isn’t easy. For example one machine wash of clothes on the best water-saving cycle uses 40 litres of water (nearly your whole daily ration). You also have to wash your hands, prepare and cook food, wash dishes, wash your hair and yourself!
Still, being extremely careful and re-using every single drop, you can stay within the daily limit of 50 litres.
Nevertheless, I am getting very weary of scooping every last drop of water out of the sink or bath tub and lifting heavy buckets of grey water to flush the loo, or carrying them down the passage and out into the garden to water my thirsty plants.
I will end up with arms like Arnold Schwarzenegger!
post script: Now it is raining more I don’t have to water the plants so much. Phew!
I find my Readers rarely click on my links (I hope due to time constraints and not lack of interest!) so that is why I included screen shots of some graphs showing the dam levels.
If you wish to have more information on the graphs in this post, you can click on this link: City of Cape Town Website.
Once again, this post took many hours to complete. Maybe next time I’ll just post a photo of cake!