Down one

Latest news from the City of Cape Town water dashboard:

Here are a few takeaways from  this week’s numbers and the information provided therein.

We are still using too much water. And by “we”, I mean people who aren’t me or my family. But even so, even with those people who aren’t me and my family, Cape Town has cut its water use by almost 50% when compared with similar periods a few years back.
Can “we” do better? Well, “we” should be able to, but interestingly, “we” have been stuck at this sort of level for a while now. Could this be some sort of impasse, and if so, why is it happening and what can the City do to get past it? There are already plenty of measures in place, but are they actually having enough effect?

582 million litres x 7 days = 4,060 million litres, but actual volume stored in the dams dropped by 8,739 million litres. That discrepancy is mainly due to evaporation because of the hot weather and strong winds we’ve seen this week over the Winelands area. So, in the last 7 days, we’ve lost an additional 8 days at 582 million litres back up to the sky. And let’s face it – it’s going to be hot and windy a lot more over the summer.

The good news is that even with this continuing overuse and huge evaporation, the dam levels “only” dropped by 1%. Simple maths suggests that with 26% of usable water still available, and using/losing 1% a week, we can last another 26 weeks. I’ve been doing some (more) rudimentary calculations and I reckon that takes us to the middle of May. We might just make it. Or not. I actually have no idea.

Because historically, water usage goes up at this time of year into summer.
However, there is some good evidence that water restrictions will curb this increase:

Taking 2014/15 as an example of unrestricted use, and comparing it with last summer (when restrictions were in force), we can see that there has been a reduction of maybe 400 million litres a day. And yes, production (blue line) is still above where we need it to be (pink line), but that graph tells a good story, and with more draconian measures in place this year, will hopefully continue to do so. Addition of temporary small scale desalination plants and tapping into local aquifers will mitigate supply issues a little too.

It rained this morning, which ruined the kids’ sports day, but at least I got another 100 litres or so from my sausages. And I’m only concentrating on that latter fact, because we’re really not in any position to complain about any negative effects of precipitation in Cape Town right now.

Chin up. We might just survive this yet. Keep saving. Every little helps.