Coca Cola "hotel"

A Gap in the Market

I’ve written before about Design for Logistics: how products themselves can ease or complicate their shipping, or the environmental impact of their packaging. I object to shipping large quantities of fresh air along with the product, and I suppose we all do, but not everything in the world nests together nicely for efficient shipping.

Once in a while, though, there comes along some holistic packaging design that’s so elegant as to take your breath away. If you haven’t already seen it, meet Kit Yamoyo: oral rehydration salts, zinc, soap and a leaflet of instructions for the care of a person with diarrhoea. The outer packaging also serves as measuring device and cup, and – here’s the clever part – it’s shaped to fit in between the bottles in a crate of Coca-Cola.

Inventor Simon Berry had observed that he could get a bottle of Coke just about anywhere, and yet far more important products such as basic medicines weren’t available. Wouldn’t it be possible to piggyback medicines onto the Coca-Cola supply chain? It was an idea that took twenty years and a lot of persistence to realise… but eventually it took off, as a result of social media.

“What about Coca Cola using their distribution channels (which are amazing in developing countries) to distribute rehydration salts? Maybe by dedicating one compartment in every 10 crates as ‘the life saving’ compartment?”

That was Simon Berry’s original Internet posting on the subject, back in 2008. Somewhere along the way, the idea was transmuted: instead of requiring the good folks at Coca-Cola to give up a fraction of their capacity in order to ship the rehydration salts, the innovative design meant that there would be no bottom line impact for purveyors of fizzy drinks. Everybody wins: it generates good press for the Coca-Cola Company (which makes a nice change from their product being criticised for being cheaper than milk)… and children don’t have to die for the want of a simple, cheap treatment.

Kit Yamoyos in a crate

Kit Yamoyos in situ, in a crate. (Photo: Colalife)

Although it’s the idea of fitting medicines into the space in a crate that brought the product and the newly-formed Colalife charity to the attention of the media, there are at least two other key components that make this grassroots supply chain work: micro-enterprise, and the use of mobile phones (specifically, SMS messages) to confirm delivery and make payments. Anybody could join in this distribution network – and earn money in the process. 

My Supply Chain Management students are already acquainted with Kit Yamoyo: I even made it the subject of one of their exam questions, last year. From a supply chain perspective, I wrote, critically discuss the approach taken, whereby the charity works with microbusinesses rather than simply giving the product away.

Students were divided on this point: some felt that a charity in possession of a life-saving treatment ought to be giving it away… and that’s the kind of aid model that I grew up with, back in the days of Bob Geldof. With a few wealthy sponsors and the assistance of the government, you probably could shift an awful lot of rehydration salts. You could just pitch the things out of the back of low-flying army transport ’plane, or something… but the purpose here wasn’t to deliver a life-saving product once: it was to change the economics of basic medicines fundamentally and permanently. With the ‘AidPod’ as a commercial product (albeit as inexpensive as possible) it gets treated differently. Stocking it at a sensible level is incentivised: tracking, and avoiding spoilage and pilfering becomes everybody’s concern. Manufacturing more ‘AidPods’ becomes something that companies want to do… and at some point between now and 2020, the whole venture becomes commercially sustainable.

Kit Yamoyo packaging

Like many really great ideas, it seems obvious afterwards. (Photo: Colalife)

Funny thing is, having created an award-winning package, Colalife are largely turning away from that design: a survey revealed that only 8% of retailers made use of crates of Coke to carry the kits. (Elsewhere in their published stats, Colalife report that they found just 4% of kits actually went into a Coca-Cola crate.)

In an effort to drive down the cost of Kit Yamoyo still further, a regular plastic ‘jar’ like the kind of thing you and I get peanut butter in has been tried… with the clever packets that fill the voids in drinks crates not entirely being phased out, but becoming rarer in the future.

“It was the space in the market, not the space in the crates that was important,” Colalife say. The Colalife website reports that approximately 60,000 Kit Yamoyos have been sold to date. Academics estimate that three lives have been saved per thousand kits used: if that’s correct, well… do the maths. While I was trying (and failing) to persuade the fishing industry to use crates made out of Pykrete, the Colalife team were saving dozens of lives – and they’re still ramping up the operation.

Let’s finish with what might be a particularly relevant message for our new MSc Supply Chain students in Botswana, Malawi, and Zambia:

“You can get any commodity/service to anywhere in the world by creating & sustaining demand & making it profitable to supply that demand.” – Simon Berry (Twitter: @51m0n)

Imagining a World Without Rainfall

Back in 1965, Frank Herbert told a story of humanity’s thirst for the ‘the Spice Melange’, a substance essential to travel and commerce, more than eight thousand years in our future. The spice can only be found in one place: an inhospitable desert peopled by much-persecuted, fanatical natives. His award-winning tale was, of course, an allegory for our own dependence on petroleum.

Let’s leave aside, for now, the idea that the motive power for our economy depends upon a scarce resource found beneath desert sands… and focus on the other precious substance in the story.

Frank Herbert’s book takes its name from the desert planet itself: Dune. It’s a place of extremes, neatly summarised in the early scenes of David Lynch’s 1984 film adaptation by statements such as “Precipitation: none. Weather: see storms.”

Not one drop of rain. Can you imagine living in a society where water is essentially a non-renewable resource, like oil? In a sense, this kind of thinking has already begun.

I was in Kenya back in 2013, when the discovery of two new aquifers in the drought-hit Turkana Basin was announced. It was estimated that the new water source held some 250 billion cubic metres of water: an astonishing windfall for a country that currently gets by on three billion cubic metres of water a year. The government announcement said that the discovery could supply the country for seventy years, although you might wonder if the perceived abundance of the new supply might increase the amount consumed – and there’s population growth to think about as well.

The textbooks say that water is a renewable resource. After all, moisture evaporates and evaporation leads to precipitation… so when did we start thinking of water in terms of years’ worth of supply before it’s gone? In a sense, this foreshadowing of the day when supplies will run out is a good thing: if water below ground is thought of as mineral wealth, to be used wisely, perhaps it won’t be wasted, but employed in such a way as to secure a lasting return on investment.

Long-time readers of Capacify might recall my article on embodied material, describing how a kilo of cucumbers embodies 350 litres of water. If that seems like a shocking amount, bear in mind that 15,400 litres of water goes into every kilogram of beef that is prepared. With accounting like that, it’s clear that the water supply can be strained to breaking point, even when large quantities are still there to be had, below ground.

When I looked at the problems of drought in Botswana, I wondered what a society does when confronted with a lack of water. The short answer seems to be that you do without: you endure interruptions in service, quality problems, and high prices… and you hope for the situation to improve over time.

What would bring about an improvement, though? Sharing with neighbours is nice, but those neighbours are all too likely to have growing populations of their own. Some of the people that I spoke to felt that technology held the answer. Desalination was mentioned a few times: not an obvious choice for a landlocked country, but there remains the possibility of a deal with a neighbouring country, I suppose. Personally, I’m concerned that the energy requirements for desalination mean that it becomes an exercise in turning oil into water. That can be done, for a time, but only at the cost of resource depletion and further climate change. It’s not an answer for the long term.

I had a look at solar-powered desalination, but found that it’s mostly being done on a very small scale. A few thousand litres of water a day is so minor a contribution as to be readily dismissed as a drop in (or more accurately, out of) the ocean.

Frank Herbert had a lot to say about the preservation of moisture: the people who live on Dune and harvest the spice wear ‘stillsuits’: fitted garments that trap the wearer’s sweat and separate out the salt, recirculating the water into catchpockets where it can be consumed again and again.

Principal characters in David Lynch’s Dune (1984)

Stillsuits in the 1984 Dune film. “Urine and faeces are processed in the thigh pads,” Dr Kynes explains. Er… OK. Lovely.

To a person in the present day that technology seems implausible, because anything that interferes with the body’s natural process of sweating would probably cause the wearer to collapse from heat exhaustion… but closed-loop systems are possible – in the plant kingdom.

Did you ever attempt to cultivate a bottle garden? I had one, in my teens. I can’t say that it was a huge success, because one species quickly squeezed out all the rest… but what remained proved surprisingly resilient to the neglectful ownership of a young person not blessed with green fingers.

David Latimer did rather better, and he had a head start, too: his bottle garden was planted in 1960, and has only been watered once since then, back in 1972.

David Latimer and his bottle garden

David Latimer and his remarkable bottle garden

The experiment began with a single seedling. This neatly sidesteps any question of one species edging the others out, leaving us with the intriguing possibility of a managed monoculture in a sealed environment, where evaporation and transpiration don’t represent a loss to the system, but simply copy the natural cycle, with dew forming on the walls of the vessel in place of rainfall. You’d still have to ‘pay’ for anything that you removed from such a system, but only what is removed. Thus you’d want to pop in some extra minerals and water, to reflect what was harvested, but a kilo of (hypothetically) cucumbers taken out would demand no more than kilo of water in, not the current third of a tonne… and you’d have no phosphates leaking into rivers, lakes and seas as agricultural run-off, because it would remain in the ‘bottle’ until you chose to extract it. (And since you’re paying for those fertilisers, why allow them to leak away?)

Now, I’m not saying that agriculture can really take place in bottle gardens. For one thing, the cost of putting vast areas of land under glass would be prohibitive. For another, it might be extremely unpleasant for a grower to work inside such a closed environment – almost as bad as wearing a stillsuit. Even so, I wonder how long we can go on accepting the current bad bargain of embodied water.

Degradation in polythene sheeting, seen in Zambia

Polytunnels offer some advantages, but don’t fare well under strong African sunlight, as I saw at the National Resource Development Centre in Zambia

Back when I worked at the University of Nottingham, I proposed a research project in ‘zero emissions manufacturing’: basically allowing nothing in but electricity (on the assumption that this could be clean energy from a sustainable source such as sunlight) and then using only materials and technologies that wouldn’t produce waste that would accumulate and degrade the system over time. I had in mind that the project would exist in several phases: a first phase in which a theoretical system was specified via environmental accounting, to identify sources of entropy, a second phase in which a ‘virtual company’ was operated, offsetting problematic wastes that caused entropy by finding practical uses for them… and a third phase in which a demonstrator sealed facility was constructed, making a sample product with nothing going up the chimney, no effluents, and no solid waste. This is a very demanding brief, because it limits the manufacturing technologies that can be used: conventional milling and grinding are out because sooner or later you’d wear away your cutting tools and want to throw them out. Likewise, deformation (bending, pressing) is preferable to cutting, because you don’t want to be generating a lot of swarf.

“Impossible,” said virtually everyone I spoke to. “You can’t have manufacturing in a closed system!”

“Really?” I said. “We’re living in one.”

Planet Earth

A Farewell Tour

This weekend, all over the nation, crowds of people are to be found, gathering to look up in the hope of seeing a very special aircraft. G-VLCN (formerly XH558) is the last of her kind, and in the very near future she will be grounded for good.

I was in Brough, a town dominated by the aerospace industry. They didn’t build the Vulcan there: that was Woodford, near Stockport. Nonetheless, XH558 treated us to a graceful lap of honour before heading off to the west.

Vulcan XH558 in flight

With the Vulcan retired, there are probably going to be far fewer UFO sightings…

XH558 is a warbird that never went to war. None of the 134 Avro Vulcans that were built were ever required to perform in their designated role, and for this we have to be grateful as the mission would have been to launch nuclear weapons in a third world war. Only two Vulcans ever went into battle – and that was in a particularly unusual capacity.

While the aircraft now known as G-VLCN wasn’t called upon to serve, its chief pilot was: it was Martin Withers (then a Flight Lieutenant) who led the attack on Port Stanley Airport, cratering the runway in the opening phase of the British operation to retake the Falkland Islands.

Those of us who study logistics and the supply chain can’t fail to be impressed by the challenges that were overcome on the night of 30 April/1 May 1982. A bombing raid involving a round trip of almost 6,800 nautical miles (12,600km) should have been impossible – even unthinkable – but it was made possible with the aid of another Cold War bomber that never bombed. The remaining Handley Page Victors had been converted to an aerial refuelling role, but they retained their own in-flight refuelling probe, which meant that they could (of course) dispense fuel, but also receive it. This permitted some indecently long flights to be conducted, operating from RAF Ascension Island.

The refuelling scheme for getting a Vulcan bomber all the way from Ascension to Port Stanley and back is something that a civilian like me can barely comprehend. You’ve likely seen footage of the aerial ballet that is in-flight refuelling: now imagine that it’s being done in the dark, in a South Atlantic thunderstorm, in radio silence, thousands of kilometres from friendly territory. A mission to get a single bomber into the vicinity of the Falkland Islands demanded eleven tanker aircraft. The refuelling plan diagram reminds me of how a troupe of acrobats form a human pyramid: the one on the top depends upon all the others… but a key difference here is that you have to construct another pyramid to safely retrieve the principal and complete the performance. You have to refuel the inbound tanker aircraft, too, for a total of eighteen air-to-air fuel transfers. Words like ‘audacious’ just don’t do it justice: it was the longest bombing raid in history. (The Americans flew further on a raid against Iraq in 1991, but the tanker aircraft were based in friendly territory along the route, so I’m not sure that qualifies…)

Although a Vulcan bomber had a fuel capacity of 41,823 litres, the overall mission consumed perhaps 623,000 litres of jet fuel in total. In a very real sense, the remarkable thing wasn’t causing a string of holes to appear suddenly in a British overseas territory, but simply being able to organise and conduct an operation of such complexity: to get the required quantity of fuel into play at such a distance from base.

Another astounding thing about the Port Stanley raids was the adaptability shown by the Royal Air Force. The Vulcans were retrofitted with an inertial guidance system that was taken from the Super VC10, making flight over the trackless ocean possible. Dash 10 electronic countermeasures pods were taken from Buccaneer carrier-borne attack aircraft, and fitted on an improvised underwing pylon, while still more pylons were added in order to carry the AGM-45 Shrike missile for later attacks on radar installations. They also added a sixth crewman (a refuelling specialist) and a chemical toilet, exceeding their maximum take-off weight in the process. Politicians may well wonder why it is that equipping the armed forces with a new system takes years and inevitably goes over-budget, while in wartime the same people manage to work miracles. This disparity between the needs and expectations of the two parties is something that I continue to study, and hope to understand someday!

The military refer to this kind of operation as ‘force projection’, and with good reason. After Flight Lieutenant Martin Withers and his crew showed that the British were serious about retaking the Falklands, and with the naval task force on its way, the outcome was never really in doubt. With the runway damaged at its midpoint, options for stationing fast jets on the islands declined, and the Argentine leadership had to wonder if the next target might be an airbase in their own territory.

The Vulcan to the Sky Trust gave XH558 the name Spirit of Great Britain in 2010, but many fans affectionately refer to her as the Tin Triangle. It’s hard to believe that the type first flew on August 30th 1952. Little more than a decade separates the type from the famous Avro Lancaster of the Second World War, yet when you compare the two, one is a crate suitable for ‘Biggles’, while the other looks like a ride for ‘Dan Dare’.

Lancaster and Vulcan in flight

Little more than a decade separates the first flights of these two Avro aircraft

How can something be more than half a century old, and all used up, and still look futuristic?

#Plasticbagchaos, or The End of the World as We Know it

Something in the business news caused a lot of passionate reactions among the English this week. It wasn’t Volkswagen’s “Dieselgate” scandal – that has gone by with barely a murmur, despite well over a million drivers in Britain being affected. No… the thing that appears to have got our national knickers in a twist is the notion of paying five pence for a disposable carrier bag.

At first glance, that makes the English seem petty, not least because the amount is very small when compared to our grocery bills, and because anybody who’s been on a European holiday (plus anybody who shops at Marks & Spencer) will have become used to paying for bags. So why all the fuss? Is Britain sliding back into becoming ‘The Dirty Man of Europe’, as some European politicians used to delight in labelling us, back in the late 1980s, before the “Dash for Gas”?

In reality, there are good reasons for debate – even heated debate – on the subject of plastic shopping bags, and their environmental harm. There are more than a few misconceptions about them, as you will find if you’re brave enough to venture into the readers’ comments section of a major media website. One recurring question is “Why can’t shops all provide paper bags instead?” This falls into the trap of assuming that ‘biodegradable’ can be considered to mean ‘benign’.

The poor old HDPE single-use bag gets such a bad press, doesn’t it? Fortunately, others have already done a life cycle analysis of various types of bag, so we don’t have to. The problem, it’s clear, is that there’s an awful lot more work and material in a ‘Bag For Life’ than in one of the disposable ones. A study by the UK Environment Agency found the following:

Number of uses required, to match the low impact of a disposable HDPE bag

Required number of uses, to be as ‘green’ as the disposable bag.

Aussie researchers Hyder Consulting also got in on the act in 2007, producing a very thorough report that details a wider range of bag types, and also studies factors such as water usage. While I’m at it I should also give a “shout out” to Patcharaporn Musuwan, a former dissertation student of mine who studied this topic at the University of Nottingham, back in 2010.

When we consider that the ‘disposable’ HDPE bag often makes its final journey into the afterlife in the form of a bin-liner, its disposal actually serves a useful purpose, and further delays the point at which reusing one of the more durable bags pays off. Then there’s (perhaps) the question of hygiene, if you’re repeatedly reusing calico bags.

Single-use carrier bags

“Simplicity is the Ultimate Sophistication” – Leonardo da Vinci

So there’s a strong case in favour of the HDPE bag… but even tiny quantities of plastics add up when national consumption is counted in the billions. As many as 7,600,000,000 bags were used in England last year, which the BBC reports to be 61,000 tonnes of the things. We’re talking about England here because, unusually, each part of the UK has separate schemes. Wales (2011), Northern Ireland (2013) and Scotland (2014) all have bag charging in place.

It’s known that a compulsory charge for bags reduces the demand for them quite sharply, by prompting people to bring their own. In a sense we can almost regard the earlier introduction of charging in the less populous parts of the UK as something of a practice run… although if so, why is it that the new rules for shops in England are far less workable than those elsewhere?

Legislators exempted small companies (those employing fewer than 250 staff) from the obligation to charge for bags, in order to spare them an administrative burden. That sounds reasonable… except that some branches of well-known small shops such as Spar, Budgens, Costcutter and Subway will be exempt because they are small franchises… while other shops that have the same name over the door must apply the charge.

With me so far? Now, you still qualify for a free bag if buying buying raw meat, poultry or fish, or prescription medicine, flowers, potatoes, take-aways…

Among those exempt from applying the charge, some are planning to charge anyway, the Association of Convenience Stores reveals… which gives them a nice little bonus, at the cost of potentially exposing front-line staff to verbal abuse from disgusted customers.

This seems like a good point to wheel out one of my favourite quotes. It’s said by Mr Bumble in Charles Dickens’ Oliver Twist:

“The law is an ass.”

I’ll be delighted if the change means fewer plastic bags end up in the sea, but as usual we’re seeing that legislation is a blunt instrument, poorly suited to making people and companies do the right thing. It’s not all doom and gloom, though: at least there have been a few chuckles along the way.

“Suddenly that huge collection of carrier bags in my kitchen cupboard is worth a small fortune,” one Twitter user quipped – and Internet satirists have been merciless since October 5th, “bag day”, began. For example…

Twitter joke re. plastic bag charges in England

5p per bag: London in flames

#Plasticbagchaos. It’s the end of the world as we know it (and I feel fine).

Botswana’s Water Crisis

I’ve just left Botswana, a place that I visit once a year as part of our Supply Chain Masters programme. I inducted ten new students there, and kicked off their first module, on the subject of supply chain strategy.

In Botswana a topic of conversation, time and again, was the shortage of water. The people of Gaborone are waiting for the rainy season to begin, but I’m told it’s been about a decade since the rain was sufficient to really fill up the reservoir at the Gaborone Dam. My colleagues have suggested that the public hasn’t been informed as to the full extent of the problem, although research suggests that the failure of supplies is hardly a secret: there’s even a neon sign in the city that reports the current level of the reservoir. The Water Utilities Corporation (WUC) also provides regular updates as to the state of supplies via its website. It makes grim reading: the principal sources of supply for the Greater Gaborone area are well below their maximum capacity:

Dam and Water Supply Situation, September 2015
Dam and Water Supply Situation, September 2015 (information from WUC, 2015)

The situation is somewhat better elsewhere, in the north of the country, but the capital is greatly inconvenienced and some southern villages are reported to have been without water for two or three weeks at a time.

Water shortages are not new. They’ve accompanied every visit to Botswana that I have made, and an article on Mmegi Online from last year illustrates the problem:

“For the first time in its history, Gaborone Dam is dying, its once proud 141 million cubic metres of water drying up to barely four metres above silt level. Of the seven water draw-off points in the Dam, six are exposed and the last is halfway in the water.

“Once the water reaches below this last water draw-off point, Gaborone Dam will have failed, depriving the 500,000 or so residents and businesses of Greater Gaborone their primary and traditional source of water.”

– Mguni (2014)

Can a dam die? Reporter Mbongeni Mguni’s article describes the Gaborone Dam as a great beast in its death throes. It’s a colourful simile, but there’s nothing wrong with the Dam: it will still be there, ready to serve again… when the rains return. In a sense, the fault doesn’t lie with WUC and their infrastructure, but with a growing population in the area – and with all of us, for our contribution to climate change.

A bad situation is becoming worse because Gaborone depends upon South Africa for some of its water. The Molatedi Dam (in the table above) is actually in South Africa. Equally, some places in South Africa depend upon water from Botswana: national boundaries don’t always reflect the infrastructure and resourcing arrangements. Under agreements that date back to 1988, cross-border transfers of water are reduced when reserves fall below a certain level. That serves to preserve dwindling supplies, but if you happen to live on the far side of a border it exacerbates the effect of reduced rainfall.

I have personal experience of being without water, although in my case it occurred in winter: our supply froze a few days before Christmas one year, and wasn’t restored until early in the New Year. For a couple of days, we clung on: showering at the gym, cooking with bottled water, and storing dirty dishes in the dishwasher, although it couldn’t be used. I was fortunate because I could bring snow and ice indoors, and leave it to melt. (Melted snow is nasty-looking stuff and you wouldn’t want to drink it, but it’s good enough for flushing toilets.) Eventually, though, we were forced to accept defeat, and we spent Christmas with relatives. Drinking bottled water is OK, but until the mains supply fails you don’t realise how often throughout the day you depend upon water for ordinary tasks, such as for washing your hands between jobs.

Next summer, we had our water pipe replaced with a frost-proof one, buried deep – at considerable expense. I hope never to be without water again: virtually everything in the household grinds to a halt, and I can only imagine what the impact would be if one were trying to run a business.

The first time I came to Gaborone there were times of day when there was no water to be had in our hotel. These times were announced in advance, and forced us to wake up early in order to shower. (The measure didn’t seem to save water, so much as to cost us sleep.) This time, there were no such interruptions, but the water in my washbasin was distinctly brownish. There’s nothing inherently wrong with water that comes with a bit of soil in it: I recall a bath on the Isle of Arran that looked like weak tea. It still got me clean: in fact, the peat-laden water was so soft, compared to that of my London upbringing, that a moderate quantity of soap caused it to foam madly.

Gaborone water, though, was water of last resort. It smelled strongly of chlorine, so obviously the water company are doing their best to keep it wholesome. Even so, I nursed my delicate British constitution by not to drinking any, and I avoided foods such as salads that would have been washed in it. (But I’m going to start suffering from scurvy if these trips get much longer…)

Tap filling a bucket with brownish water

Water supply as seen recently in Gaborone [photo: Fahmida Miller]

This is a report without a satisfactory ending, because the story itself hasn’t yet ended. The people of Gaborone can only wait, and hope that the situation improves. WUC have to do more than merely wait and hope, reacting quickly to reports of leaks and delivering water by truck where necessary. The government of Botswana can’t just wait and hope, either: they’re engaged in large-scale, not altogether successful schemes to pipe water over longer distances, including some from neighbouring countries. There is also a long-term plan of drawing water from the Zambezi, but Botswana’s Zambezi riverfront at the ‘Four Corners of Africa’ (the border between Botswana, Namibia, Zambia and Zimbabwe) is tiny: just a point on one bank of a 2,574km river. In such a situation, how much water is it reasonable to extract from a river that others also depend upon? Perhaps the tremendous flow of the Zambezi means that dipping into this shared resource won’t cause friction? On average, 1,088m3 of water per second goes over Victoria Falls, not far downstream… but even if water is so abundant as to be considered free, such engineering projects require time. Meanwhile, Botswana’s capital must continue to function, somehow – as must the nation’s water-intensive mining activities.

In the same week, one of my lectures was on the subject of the sustainable supply chain. I explained that sustainable materials are things that grow, or are refreshed by natural processes. Water is a sustainable material, per this definition… which serves to underline the difference between ‘sustainable’ and ‘being sustained’.

 

References:

Mguni, M. (2014) ‘A requiem as Gaborone Dam gives up the ghost’, Mmegi Online, October 10th. Available from: http://www.mmegi.bw/index.php?aid=46594 (accessed 03/10/2015)

Water Utilities Corporation, WUC (2015) ‘Dam Levels’, available from: http://www.wuc.bw/wuc-content.php?cid=109 (accessed 03/10/2015)