If all the world’s
water was a bucket
full, only one
would be drinkable
50 litres person / day
• Day Zero is the word given to the apocalyptically named point when water in the six-dam reservoir
system falls to 13.5% of capacity.
• At this critical level, piped supply will be deemed to have failed and the city will dispatch teams of
engineers to close the valves to about a million homes – 75% of the city.
• In place of piped water, the city will establish 200 water collection points, scattered around the city to
ensure the legally guaranteed minimum of 25 litres per person per day within 200 metres of every
More information here:
Identify – What can you
see in the photo?
Describe – What is the
problem that exists
Explain – Why do you
think the problem has
happened? What has
Apply – What are the
possible solutions to the
problem? Are some more
sustainable than others?
Link – Is this issue an
example of human or
What other topics?
• Growing population – and at a faster rate than water supply capacity was
• Increased affluence – more devices that use water installed in homes
• Vineyards around Cape Town growing in area, and requiring large
amounts of water
• Ageing infrastructure – leaking pipes
• Drought for several years
• Increased pumping from aquifers
• Slow pace of investment in alternative supplies
Also social pressure to reduce usage…
A resilient city?
Cape Town is committed to becoming a resilient city and is part of the 100
Resilient Cities Initiative. It is therefore both prudent and appropriate for the
city to take climate change risks into account in its planning. In line with
international best practice thinking for coastal cities, Cape Town’s resilience
will be increased through the diversification of water supplies away from
dependence on surface water only towards a situation where the city also
obtains a share of its water from ground water, wastewater reuse and
seawater desalination. Consequently, a resilient city will be able to both
optimise and sustain water use through integrated management of four
sources of water – surface water from rainwater (including urban storm water
runoff) managed in dams and wetlands, ground water (with recharge),
reused wastewater and desalinated sea water.
From Cape Town Water Disaster Plan document
As recently as January, rationing with armed
guards for 4 million people was on the horizon.
Daily ration of just 25 litres per person / day
The most recent situation can be seen on the
Demands on water
How far do 50 litres of water go?
Residents of Cape
Town have been
asked to limit their
use of water to 50
litres a day, which is
less than a third of
the average daily
water use in an EU
Match the numbers
below to the activity.
159 litres 125 litres 582 litres 177 litres
382 litres 150 litres 45 litres 232 litres
Shower – 45 litres
Bath – 125 litres
Flush – 150 litres
Wash dishes by hand – 159 litres
Dishwasher – 177 litres
Washing machine – 232 litres
Water garden – 382 litres
Wash your car – 582 litres
The restaurant is harvesting grey water
from air-conditioning units, boiling ice-
bucket water to mop floors, disconnecting
scullery hoses, installing new tap diffusers,
using disposable napkins, discarding table
But the real innovation – which eliminates
the need to wash 5,000 plates a week – is
serving two of his tasting menu courses on
disposable cards that fit into an empty
picture frame; in The Drought Kitchen the
entire six-course menu will be served this
The dishwasher and laundry will need just
10% of the water they used to.
Your job is to assess the relative merits
of a number of possible solutions to the
Use the displayed information (and
your devices) to complete the sections
in your notes)
You will then be given a chance to vote
for your preferred option(s)
Possible – all scenarios which are possible
Probable – which of the possible scenarios
are most likely
Preferable – of the probable futures,
which one would be the most preferable
in terms of sustainability or in maintaining
as close as possible to the current quality
of life for residents
Cape Town-South Africa
Water Crisis by
Cape Town Twitter
Top Tip: Follow the Twitter accounts of organisations connected with topics you are
S With thanks to Tom Morgan Jones
for illustrations from
Mission:Explore Water (2013) by
S Mapping on Water Security by
World Resources Institute:
S With thanks to Ben Hennig for
Worldmapper mapping – CC
licensed for use
S With thanks to previous IB
Geographers from Ecolint 2012
who took part in my Water
Check out the Water Diaries website too
S With thanks to Joanna Payne for a
couple of slides and activities from
a presentation she shared.
S Resource watch:
S CBC has a range of stories in a
series on Cape Town:
tml - downloads of data, and
Google Earth files to see threats to
global rivers through human water
Some slides taken from Cape Town Critical Disaster Plan
Thefts of supplies
As if the drought is not bad enough‚ the City of
Cape Town is having to battle against thieves
stealing from aquifer drilling sites‚ resulting in
“delays of weeks at a time” to bring more water
The city said in a statement on Sunday it is
something that it can “ill afford”. Tools‚ batteries‚
vehicles and any materials considered possible
scrap are being targeted by thieves.
1: Water for Energy exchange
Turning sea water into potable water takes vast amounts of power. Israel's
desalination plants usually only run overnight to take advantage of lower
EcoPeace, an environmental NGO made up of Jordanian, Israeli and Palestinian
activists, is floating a new idea to harness the sun-soaked deserts of Jordan, and
sell the solar power to Israel and the Palestinian Authority, who would use it to
run desalination plants.
"By advancing a water-energy exchange we're creating some stability, we're
creating an atmosphere of co-operation," said Gidon Bromberg, the Israeli
director of EcoPeace.
Bromberg said all three governments "have expressed support" for the Water &
Energy Nexus, which is projected to cost $30 billion. Despite the price tag, "not
only is it realistic but it's absolutely essential," given the region's water woes.
Bromberg said the idea could bring wider benefits: "it's certainly stability, it's
certainly security, and those are two essential ingredients for peace."
2. Aquifer drilling
Water is stored in certain types of rocks, and a store of this kind
is called an aquifer.
Boreholes can be drilled to access this water, but this is time
consuming and expensive, and can also result in a lowering of
the water table locally.
Cape Town plan involves:
Prioritise groundwater extraction: Fast-track extraction of water from Cape Flats
Aquifer (CFA) and Table Mountain Group (TMG) Aquifer. Both these
aquifers have significant storage volumes. The water use licences provide for
yields of only a fraction of the available storage, and yields will be maximised
in the short-term within the annual allowable volumes. Groundwater is also
subject to the impact of drought but with significant time delay. The CFA
license requires recharge from treated wastewater to replenish the aquifer and
improve water quality in some instances.
Water can be extracted from sea water using a process called
This is very energy intensive, and takes a large plant to do on a
scale which will make a difference to a city the size of Cape
Cape Town is intending to invest in this technology as it
provides ‘new’ water rather than using other surface and
From the Cape Town Disaster Plan:
Decisions around desalination must not be delayed. Desalination
provides the only “new” source of water, and other than technical and
financial constraints, has unlimited augmentation capacity.
5. Punitive bills, but with incentives for low use
Punitive tariffs: Restrictions go hand-in-hand with stepped tariffs, charging
more for water use at higher volumes. Progressively more punitive tariffs
have been introduced on inclining blocks so that higher use of volumes
come at an increased cost.
Level 6 tariff was introduced on 1 February 2018 where punitive tariff
applies to all use over 50lcd. Water is still cheap compared to other goods
and services, and is supplied to every formal household. As households are
now required to dramatically reduce consumption, the volumes in higher
usage steps have shrunk considerably.
Wastewater reuse is expected to be less costly compared to desalination
because the capital costs are lower (no expensive marine works are
needed) and energy costs are about half of that needed for desalination –
2 kWh for reuse compared to 3.5-4 kWh for desalination per thousand
The latest engineering estimates for treating wastewater reuse to a
potable standard in Cape Town is about R7.50 per thousand litres, just
more than half the cost of efficient desalination. Scale is reasonably
important for wastewater reuse too.
Asingle wastewater reuse treatment facility for 50 million litres per day is
about 15% cheaper than a 20 million litres per day facility, and a single
combined facility of 70 million litres per day is strongly preferred for
operational reasons and is cheaper compared to two separate facilities.
6. Reusing waste water
Antarctica is relatively close to South Africa.
Feasibility studies have been carried out into the possibility of towing
icebergs to Arabian states previously.
7. Towing icebergs from Antarctica
Synthetic fibre ropes, which are stronger than steel, can be slung around icebergs at the waterline,
but when tugging begins the rope can slip off or make the iceberg roll over. Another reason the
towing must be done slowly and carefully is that dragging an iceberg through the ocean can make it
break apart. The industry has come up with nets for capturing unstable icebergs, but they don’t
work in every case. “There are two major problems: one is getting a vessel that’s strong enough to
tow the size of iceberg you need. The second is breakup and melting. It would probably be feasible
to get an iceberg a kilometre or two wide up to the Arabian sea, but you’d lose an awful lot of mass
on the way. It’s quite likely it would fracture before you got there.”
And then there is the cost. A single iceberg-towing vessel can cost around $75,000 a day, and to tow
a massive iceberg might need several ships for months at a time. “It comes down to the question of
what is feasible and what is practical. Is it more practical to take a tanker to Antarctica and capture
some fresh water melting off a glacier?” In Canada, shops already sell bottled water made from
chunks of frozen water that are chipped off icebergs. King has a chunk in his freezer. “It makes for
nice ice,” he said. “It makes a nice crackly sound in a glass of water.”
A lot of water is lost from pipes, and not always detected.
Fixing and improving infrastructure would result in less losses, and create
a more efficient system which would continue to provide benefits in the
Finding the leaks would be a lengthy process.
8. Fixing the leaks
9. Taxing the wine industry
A lack of rainfall in the Winelands that dot the Western Cape of South Africa has entered its
third season in a row, resulting in an undersupply of water for irrigation. The shortage is
intensifying pressures on an industry that employs roughly 300,000 people and forms the
backbone of the provincial economy. South Africa produces some of the world’s most
popular wines but it struggles with profitability, on average, the local wine industry returns
about 1% on investment,
Depending on the region, vines generally need between 250 and 600 millimeters (between
10 and 24 inches) of rain annually to survive. Though temperatures and precipitation vary by
region, South Africa’s Winelands have, on the whole, received about half as much rain in the
run-up to the annual harvest, which began in early January.
Dams that supply irrigation water to the vineyards stood, on average, 26% full in mid-January
compared with about 42% full a year ago. The deficit triggers quotas that have cut the
amount of water available at some vineyards by as much as 80%.
“We simply don’t have enough water to keep up with the irrigation requirements,” said
Francois Viljoen, consultation service manager for VinPro, a nonprofit that represents South
Africa’s wine industry. “The water stress is starting to show. The result is smaller berries,
which affect your volumes. And you also have less juice in the berries.”
Why is Cape Town facing ‘Day Zero’ and how can it be averted?
• The reservoirs that supply water to the city of Cape Town are nearly empty due in part to below-average rainfall for many years in a
row, but also, and maybe more importantly, because of increased abstraction.
• Since 1995, Cape Town’s population has grown by 79%, while water storage only increased by 15%, straining the region’s existing
• Day Zero is the word given to the apocalyptically named point when water in the six-dam reservoir system falls to 13.5% of capacity.
• At this critical level, piped supply will be deemed to have failed and the city will dispatch teams of engineers to close the valves to
about a million homes – 75% of the city.
• In place of piped water, the city will establish 200 water collection points, scattered around the city to ensure the legally guaranteed
minimum of 25 litres per person per day within 200 metres of every citizen’s home.
• The government has struggled to keep pace. Plans to make the city more resilient to climate change by diversifying the water
supply with boreholes and desalination plants were not due to kick in until after 2020. But the climate has moved faster, bringing a
drought so severe it would usually be expected only once every 384 years.
• Some people believe Cape Town’s vineyards bear a large share of blame because they are water-intensive yet they have continued
to expand during the drought.
• Many hotels have removed the plugs from rooms so guests must have a shower rather than a bath. Some shopping malls have
turned off the taps and installed hand-sanitiser dispensers.
• Maintaining social programmes will also be a challenge. City officials say hospitals and prisons will run as normal because they have
access to aquifers, but questions remain about 819 schools, half of which do not have boreholes. There would be sanitation risks if
their toilets were unable to flush, but the authorities insist they will remain open.
• The scramble for water is already raising tensions among residents. Freshwater springs now require 24-hour policing as congestion
builds in surrounding streets and there have been sporadic reports of fights break out in the lengthy queues.
• Shame is used to maintain discipline. An online water consumption map allows neighbours to check on each other’s usage. Some
sports clubs have installed buzzers on their showers that embarrass people who linger under the water for more than two minutes
• Even though extreme droughts are difficult to predict, researchers point out that the city council has failed to adapt the local water
supply to the demands of a growing metropolis.
What the City is doing:
Restriction Level 6B: Level 6 was enforced from 1 January 2018, and 6B from 1 February 2018.
The target has been reduced to 450MLD. Daily individual consumption must be limited to a
maximum of 50 lcd to be aligned with Level 6 tariffs. 4 million people at 50 litres per day =
200MLD. Approximately 150MLD is consumed by industry, commerce, government etc. This
results in 100MLD less than the daily target of 450MLD. The inability to adhere to restrictions thus
far means that a stretch target of 50 litres is appropriate to ensure that the 450MLD target is
Communication campaigns: Every person in the city needs to realise that this is a crisis. The city
has launched numerous communication campaigns to assist people in reducing their
consumption, such as household leak detection & repair and how to use 50 litres, and continues
to use radio, print and social
media to reach every citizen and mobilise to reduce consumption to 450MLD, aligned with 6B
Pressure reduction: Pressure reduction was initiated more than a decade ago and has been
accelerated to automate zones across the city to optimise the system and reduce demand -
especially the impact of leaks. Pressure zones are being used to force down consumption by
throttling zones to the extent of partial supply if user behaviour in the zone is high in an effort to
meet the daily water budget. Savings of nearly 50MLD have been affected so far.
DWS = Department of Water and Sanitation
MLD = Million litres per day
• Household flow regulators: The city has been installing water management devices to
manage debt for many years. The programme has been dramatically ramped up to
households who have not reduced consumption to restrict daily household consumption
and safeguard against the impact of leaks. In many cases this was due to undetected leaks,
but under level 6 restrictions, the city will install these where consumption is higher than
10.5kl/month. A household of 4, each person using 50 lcd results in a monthly
consumption of 6,000 litres per household. The allowance is per day, whether at home,
work or school. Note also that the average household size in Cape Town is 3.2 people.
The water companies would have preferred to manage household consumption through smart
metering – similar to electricity, using pre-paid metering or remote monitoring and control –
due to low cost of water this has not been viable. The city has installed more than 250,000
water management devices over the past decade. Household demand has declined
The city has engaged with large and small business with possible solutions and is
working to incentivise reduced consumption. Avenues still to be evolved include usage
of private boreholes in the system.
Information to drive behaviour change: Examples include the Star rating tool for
buildings, and making visually available household consumption data to incentivise all
households to stay within usage limits (dark green & green dots).