The capacity of the Table Mountain dams

Yet another so-called anomaly pounced upon by the conspiracy theorists when it comes to the Cape Town water crisis is that of the Table Mountain dams.

Yes, there are five dams on the top of Table Mountain. They were built there during late 1800s and early 1900s as the population of Cape Town expanded and more water was required. Maybe we should have tried this idea more recently too. Anyway, you can still visit the dams on the top of the mountain (but be careful) and you can still see a lot of the late Victorian infrastructure running through Newlands Forest.

The dams are  Woodhead (1), Hely-Hutchinson (2), Victoria (3), Alexandra (4) and De Villiers (5). The other blue area towards the suburbs on the right is the Kirstenbosch dam, and doesn’t count here.

Anyway, there are two questions that people are asking about the Table Mountain dams. Firstly, why are they so full compared with the other dams out east (79.9% vs 25.9% on February 1st)?

Table Mountain is a 1km high lump of rock surrounded by very little other stuff which is 1km high. Its location right down in the very bottom corner of Africa, ostensibly bordered by the Atlantic Ocean on 2½ sides means that it has its own microclimate and is a veritable magnet for rapidly condensing air. It’s regularly moist on top. It’s one of the reasons that the dams were built there in the first place (the other being the use of gravity to produce water pressure).
Newlands’ proximity to the mountain explains why it is so wet compared with virtually every other Cape Town suburb. And also why it’s dark there by 2pm every day in winter. So yes, the top of Table Mountain is more regularly wet than most anywhere else in the metropole (including Newlands).

And that’s why those dams are fuller than you might have expected.

Next question – why aren’t we using that water?

Well, right now, any water is good water. So don’t get me wrong when I tell you this. But there’s actually not much water in those dams, even when they’re full.

Those 5 dams (together) have a total capacity of 2376 Ml.
Theewaterskloof (alone) has a total capacity of 480188 Ml.
That’s over 202 times the combined capacity of the Table Mountain dams.
And even though Theewaterskloof is very, very empty (13%) at the moment (see here) (and not here), there’s still 24 times more water in it right now than there is in the (80% full) Table Mountain dams.

The total capacity of the Big 6 dams supplying Cape Town is 378 times the capacity of the Table Mountain dams. Scale.

Even if we could (and did) empty what’s in those dams, it would only give Cape Town about 4 days water, which is certainly not to be sniffed at, but is not going to save a doomed city of 4 million residents either.

 

I hope that has answered your questions.
Have a special day.

 

The Blame Game

OK. Here goes. I rarely do “opinion” posts on the blog any more because there’s rarely anything I feel strongly enough about to be bothered to wade through mentions on Twitter, comments on here, insults flung at me on my journey to and from work and hate mail delivered to my home address three months later via the SAPO.

But I feel I need to say something.

I’ve been  watching the Cape Town water crisis with interest for a long while now. I’ve blogged about it an awful lot. And while “crisis” seemed a strong word 25 months ago when water restrictions were first introduced, we’re now staring down the barrel of a rather terrifying gun, with fewer than 100 days left until Day Zero – the day the taps will be turned off.

An entire city of 4 MILLION residents is going to run out of water in just 3 months time. And yet, a quick glance at the City’s Water Dashboard gives us this picture:

What, if I may be so bold, the actual fandango?

Just 39% of residents are using fewer than 87l water per person per day. That’s frankly appalling, and it shows a huge disregard and/or misunderstanding for the gravity of the situation.

You think that showering with a bucket is inconvenient? (It can be, I agree.)

But when Day Zero arrives:
There will be no water in your home. None.
Literally nothing will come out of your taps.

Want water? Go to one of the ±200 city-wide collection points and queue for it. 25 litres per person per day.
25 litres of water weighs 25kg, by the way. Transport that, mate. Every single day.

Businesses will be forced to close.
Closed business = no income = staff being laid off.
Schools won’t be able to open, creating a childcare nightmare for parents, and an educational nightmare for schools and students.

And Day Zero won’t last a day. The biggest misnomer since Pussy Galore, right there. Day Zero is when it starts.
Brace yourself for 3-6 months of no water supply.

Sadly, if scare tactics – or “the truth” as most people call it – worked, we’d already be doing a lot better than we are.

But I digress. This paragraph from David Olivier’s independent report on the current crisis has stuck with me:

Blame shifting, fault finding and panic are usual reactions to water crises all over the world. Some anxiety is good, as it motivates water saving, but blame shifting actually pushes responsibility away, and causes water wastage. The best attitude Cape Town’s people can adopt is for every person to do their best, together.

(emphasis by me)

This isn’t a political post. Absolutely not. I have no party axe to grind. But it does seem to me that there is a blame culture which has flourished in recent weeks. People saying that this water crisis has been poorly-managed by the City.

My personal feeling is that they’ve done ok considering the lack of any precedent here and the 20/20 hindsight that their detractors are blessed with. I think any city, any government, any party would have struggled with the challenge of a 1 in 1000 climatic event:

And I’m always intrigued to hear what the critics would have done differently.

But those are just my thoughts. Other opinions are available.
And, as I’m about to point out, none of that actually matters anyway.

I think David is absolutely right: this blame game has given people a convenient scapegoat which in turn has led to them choosing to ignore what, in this situation, are very clearly their social responsibilities.

So here’s my plan.

Blame and anger don’t contribute to our water supply. That’s not how the water supply works.

You can’t drink outrage.

If you want to stick it to Patricia de Lille, the City, the DA, the Provincial Government, the National Government or whomsoever, then next time your opportunity to vote comes around, you must do just that.
That’s how democracy works. Literally, the power of the people.

(Remember to choose wisely, just in case this happens again.)

But attempting to spite any or all of those individuals or bodies by refusing to cut down on your water usage is misguided and isn’t going to help anyone. Even yourself.

Spoiler alert:
Your political affiliations and opinions are not an excuse to not save water.

It’s time (it was time a long while back, actually) to put on your big boy panties, take a step back (and up) and choose to overlook the petty politics right now.
Deal with stuff that later.

Right now, collectively, we need to reach out to that missing two-thirds of residents who are still using too much water – the Day Zero denialists, the monied individuals in Bishopscourt, the Observatory anarchists, the tannies in Pinelands with their precious lawns, that oke in Durbanville that just doesn’t care – and rein them in. And if they want to moan all over the newspapers and social media and and and… about us doing it, well they must knock themselves out.
Just as long as they’re saving water while they’re doing it. Because if they don’t come to the party, we’re very definitely doomed.

I’m aware that this is pie in the sky thinking. I’m aware that if people actually cared about this situation, they’d be saving already. But just imagine if the residents worked with the City instead of pointlessly fighting the system (“pointlessly” because as I’ve pointed out – using water just because you hate the DA is a recipe for disaster), fiddling as Rome burns.

If you’re one of those individuals I’ve mentioned above, you’ve probably not read this far. But on the off-chance that you have, for the good of everyone: rich, poor, black, white, young and old please can you please start saving some water?

We need to pull together here. Or we’re all massively, massively buggered.

 

(Don’t @ me.)

First!

A quick test.

Who was the first man on the moon? (1969)
Who was the first person to reach the South Pole? (1911)
Who was the first person to receive two Nobel prizes? (1903 & 1911)
Who were the first men to climb Mount Everest? (1953)

I’d guess that you knew most of them. And with good reason, because firsts are important and while someone can always do it Citius, Altius or Fortius-er – they can never take away the honour of being the first from you.
So let’s celebrate the fact that Cape Town stands now on the very brink of being the first major city in the world to run out of water. As recognised by Time magazine, no less:

Other minor places have run out of water before – our near(ish) neighbours in Beaufort West allegedly expired back in November. But Beaufort West is – at best – a town, and is – very definitely – minor. Cape Town is about to make history in the same way that Hiroshima did back in 1945.

Of course, everyone saw the Hiroshima thing coming (but it clearly happened anyway), so what about Cape Town? Aryn Baker (for it is she) goes along with that independent report:

City planners have long pointed out that Cape Town’s water capacity hasn’t kept up with population growth, which has nearly doubled over the past 20 years. Still, a three-year drought on this scale is a “once a millennium” event, say climatologists, and even the best-planned water system would have taken a hit under current conditions.

Indeed.

So while we might not have any water in 3 months; while our sewage systems may be collapsing around our ears (or whatever other parts of our bodies); while the very fabric of our lives is torn from all around us – ain’t no-one that can take away that first place from us. Not ever.

Be proud, Cape Town. Be proud.

Sewing doesn’t help

Yesterday was nice. Really nice. A couple of light showers and drizzle for most of the day. A miserable Sunday at any other time or in any other place, but we loved it. The garden was sighing with relief, the rainwater tanks were refilled, and we got at least another 1200 litres into the pool, whose situation had, in all honesty, been looking a little precarious.

It was like someone had pressed a reset button. Wonderful.

But this was small scale, of course. Yesterday won’t have made any meaningful difference to our water crisis. It just made my lawn feel a bit happier. We need real, heavy, prolonged, regular rain to sort out our water problems.

But yesterday was nice. Really nice.

While I’m on the subject of the water crisis (but then actually, when am I ever not?), let me remind you that sewing doesn’t help the situation. Not sewing as in stitching a couple of pieces of fabric together (although that won’t assist us either), but SEWing.

SEW stands for Someone Else’s Water, and SEWing is a new concept that I have noted recently and named, like the Stable Genius™ I can like to be.

Saving water has become, in some circles at least, intensely competitive.

Bring it on, I say.

If my triumphant, vaguely arrogant assertion at a braai that “We’re down to 50 litres a day” somehow spurs you into trying to reduce your daily water usage, then that’s great. Everyone benefits.
But your reduction must be a genuine one, made by saving water in your own home. It’s no use merely SEWing. That doesn’t help anyone.

SEWing is the act of ostensibly saving water, but merely doing so by diverting your actual usage onto someone else’s account. There appear to be many ways to SEW, all of which will lower your household water bill, but won’t help the overall water crisis situation in any way. Handing your washing over to a local laundry. Watering your garden using a hosepipe attached to next door’s tap while they’re away on holiday. Showering at the gym. Washing your car at a local car wash. Saving that big poo for work.

Spoiler alert: Just because that water doesn’t appear on your municipal bill doesn’t mean it isn’t getting used. It’s all coming from the same worryingly empty dams.

Your rates bill may look good, your car may look good, your garden may even look good if (in an entirely hypothetical situation) your neighbour asked you to keep an eye on their property while they went to Europe for Christmas [nervous cough], but it’s a hollow victory.

So if you’re a closet SEWer, you’ve been rumbled. I’m on to you and your despicable, duplicitous, deceitful actions. It’s time to think again. Because you’re not moving Day Zero out by dropping the kids off at the pool at the office.
And your colleagues hate you for it too.

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.