In the guide below, we break down the past water shortage/water crisis experienced by Cape Town, as a case study on water supply issues.
We identify what the shortage entailed, some of the potential main causes, as well as what the main solutions and takeaways might have been.
This case study might be complementary to our separate case study on water scarcity issues in Perth, Western Australia.
Summary – Cape Town Water Shortage Case Study
What Was The Cape Town Water Shortage?
The Cape Town water shortage event, also referred to as the ‘Cape Town Water Crisis, was a shortage of the municipal dam water supplies
When Did The Shortage Happen?
According to wikipedia.org, dam levels had been decreasing since 2015, but reached their peak crisis level in mid-2017 to mid-2018 where water levels hovered between 15 to 30 per cent of total dam capacity
Did Cape Town Reach ‘Day Zero’?
No, they didn’t.
The main cause according to some reports was:
– A severe drought that limited rain water inflows to the city’s dams (which is the main water source that Cape Town relied on for their water supply)
An indirect factor for the drought, may have been a changing climate and changing weather patterns, according to some reports
Other Potential Causes
There were other potential causes that contributed to the event too.
Some of those potential causes may have been:
– Cape Town’s reliance on rainfall and their dams to provide a fresh water supply for the city, without diversifying to other water sources that were less dependent on rainfall or affected by the climate
– Not planning for the drought because it was ‘an out of the norm event’
Some also argue that the general management of Cape Town’s water strategy by the Cape Town government and water management planners/decision makers could have been better
However, it’s worth noting that there were some water strategy actions being taken prior to the shortage.
– An increasing population, and an associated rising demand for finite water resources
– Other factors which are listed in the guide below
A few of the significant effects of the shortage were:
– Severe water restrictions to the municipal supply of water
– Economic and social effects, which impacted various aspects of the city in different ways
We list some of the effects of the water shortage in the guide below
How The Shortage Was Alleviated
The water shortage was eventually alleviated in large part because of:
– Water restrictions being imposed (that reduced demand for finite water supplies)
Residents had to significantly decrease their daily water usage, along with the agricultural sector and businesses having to decrease their daily water usage too
Some farmers for example agreed to decrease water use
– Increased water tariffs
– And, also because of rainfall restoring/refilling dam water closer to it’s full capacity
Dam levels rose from around 15 to 30% of maximum supply at the worst of the crisis in mid 2017 to mid 2018, to around 70% in mid September 2018 (according to wikipedia.org)
Short Term & Long Term Solutions Implemented During & After The Water Shortage
There were a list of solutions that Cape Town implemented to address the water shortage
There were also longer terms visions and strategies proposed to help with Cape Town’s long term water strategy to sustainably manage water supplies
We list some the other solutions in the guide below
Challenges Encountered In Implementing Long Term Solutions
There were a number of challenges encountered when attempting to implement long term solutions
For example, some solutions like desalination were costly, or had logistical challenges
Desalination and water recycling both faced issues to do with water quality, and persistent organic pollutants in water that was to be used
We discuss some challenges in more detail in the guide below
Cape Town might look to other cities for examples of how to potentially deal with water scarcity issues.
Perth, Western Australia is an example of a city that was facing similar challenges to Cape Town, but managed to avoid water shortages with a diversified and effective water management strategy. They are now mainly reliant on desalination and groundwater, instead of their dams
What Was The Cape Town Water Crisis/Water Shortage?
It was a shortage in the municipal water supplies coming mainly from 6 major dams (although there were some other minor dams too), to most notably the City Of Cape Town (and the Western Cape region)
How Much Did Water Supply Levels Decrease, & To What Point?
According to several reports:
Water supply levels (i.e the reservoir levels in the 6 major dams that supplied the city with most of it’s water) decreased from about 70%, to 15 to 30% of total supply quantity at the lowest period of the shortage
When Did The Water Shortage Happen?
According to wikipedia.org, the peak of the crisis was around mid 2017 to mid 2018, although it’s worth noting that dam levels had been slowly decreasing since 2015.
What Is ‘Day Zero’, & Did Cape Town Avoid It?
Day Zero would have been the point in the water crises where the water level/water capacity of the major dams supplying the City would have fallen around 13.5% or lower
At this point, Level 7 water restrictions (when municipal water supplies would be largely switched of) would have been imposed.
However, Cape Town avoided Day Zero during the crisis
Although, several reports indicate Cape Town did reach somewhere between 15% to 30% of dam capacity, and did also reach Level 6B restrictions, so, they may have gotten close to ‘Day Zero’
Did Cape Town Actually Run Out Of Water?
No, they didn’t, because they never reached ‘Day Zero’ (which is considered by many to be the point at which a city ‘runs out of water’)
What Caused The Water Shortage?
The Western Cape Town region water supply system was heavily dependent on rainfall to it’s dams (according to waterstories.co.za, even now, approximately 98% of Cape Town’s water comes from dams, and 2% from ground water)
A severe drought (which resulted in a lack of rainfall for a period of time) was reported as the main cause of the shortage
One report indicates that this drought was about a one in 300 year rare event
Some reports indicate that the occurance of this drought was linked to a changing climate and weather patterns
Some of the other causes of the shortage may have been:
– A failure to plan adequately and have measures in place for the possibility of a drought
Local government and those in charge of water supply management may have been responsible here
One reason given for the failure to plan was that this drought was such an ‘out of the normal event’, and couldn’t have reasonably been forecast to occur when it did
– Failure To Diversify Water Sources
The city was reliant on it’s dams and rainfall to the dams for it’s water supply, with no other major water sources feeding their water supply
A more diversified water strategy consisting of more water sources may have helped
– Population Increase
Population increase can lead to an increase in demand of water, or greater water consumption
The population of Cape Town had grown significantly in a 20 years period according to several reports, which increased demand for water
– A Smaller Per Capita Water Supply Than Other Cities Worldwide
This is the ratio of available water supply to the number of people in a city (i.e. the population size)
According to theconversation.com:
Cape Town has small water capacity/supply per person from it’s dams
Brisbane has 2,220,150 ML storage capacity for its 2.2 million residents [and …] That amounts to just over one million litres per resident when storages are full.
In comparison, Cape Town’s four million residents have a full storage capacity of 900,000 ML. That’s 225,000 litres per resident
– Other Potential Issues With Decisions Makers
Some reports indicate there may have been the following issues for and amongst water supply strategy decision makers – disagreement between different political parties, withholding of funds, increasing debt, corruption, and other issues
– Other Existing Water Issues
Such as ‘… poor water management and infrastructure problems at dams and other collection points’ (climate.mit.edu)
– Invasive Water Hungry Plant Species’
These plant species grew in the area, and reportedly around the dams
They are water hungry, which some reports indicate led to declining water supplies in the range of 3% to 7% of the water supply (by some estimations)
What Was The Impact Of The Water Shortage?
Some of the effects of the water shortage may have been:
– Significantly Reduced Water Use For Residents, Businesses, & Agricultural Sector
There were strict water restrictions put in place, which limited water use for everyone living in Cape Town
Residents had to severely decrease daily water usage
Agriculture and businesses in the region also had to decrease daily and overall water usage
– A Range Of Social & Economic Effects
There were a range of other economic and social impacts of the water shortage
Industries such as agriculture and tourism were reported to be impacted economically (at least by decreased water for production and business activity in the case of agriculture)
Socially, there may have been an impact on low income and vulnerable people, and also on public health, civil unrest, unethical water sales behavior, occupational health and safety, childcare, and the risks involved with fires.
In general, water is important to society for a number of reasons, and the biggest water users such as agriculture, industry, and the municipal sectors are impacted, as well as those who consumes goods and services from these sectors (or, those who depend on these sectors)
wikipedia.org and insurancejournal.com list more of the potential impacts in their reports
What Brought An End To The Water Shortage?
Around September 2018, dam levels reached around 70% of total capacity, up from around 15% to 30% in mid 2017 to mid 2018
This essentially ended the water shortage
Dam levels reaching 70% was mainly a result of:
– Water Restrictions
According to wikipedia.org: ‘[Cape Town] implemented significant water restrictions in a bid to curb water usage, and succeeded in reducing its daily water usage by more than half to around 500 million litres (130,000,000 US gal) per day in March 2018’
These water restrictions started to ease around September 2018
According to waterstories.co.za: ‘[There was a] massive reduction of water use under Level 6B restrictions of 50 litres per person per day and various other initiatives [implemented to keep] total usage to around 500 ML per day’
– Increased Water Tariffs
Especially for those using the most water, or using water past defined limits
– Strong Rains Starting Around June 2018
Towards the second half of 2018, Cape Town decreased water restrictions as dam level rose with increased rainfall
*There was also rain in 2020 that was an unofficial end to the drought, and brought dam levels to around 95%.
List Of Short Term & Long Term Solutions Implemented Or Explored, During Or After The Water Shortage
Short Term Solutions
– Water Restrictions
Water restrictions involved banning outdoor and non-essential use of water, encouraging the use of grey water for toilet flushing, and aiming to limit the overall per person water usage
– Increasing Water Tariffs
– Multi Stage emergency Plan Prepared
There was a multi stage emergency water plan to protect the water supply that was left (with increasing levels of restrictions right up to shutting off water supplies and setting up water collection points around the city to control total water supplies)
– Buying Water Supplies From Nearby Regions
Involved buying additional water supplies from other water reservoirs in other regions.
Another water user association eventually agreed to some of their dam water supplies be transferred to the Cape Town supply for free
– Temporary Desalination Plants
However, one report by climate.mit.edu indicates that Cape Town ‘… spent the majority of its R1.4 billion ($86 million) drought-related budget to construct three emergency desalination plants, which delivered critical water supplies’
However, various report indicate these plants were eventually abandoned
– Regulation Of Common Pooled Water Resources
– Bringing In Bottled Water To The City
– Residents Has To Find Various Ways To Source Water
Included but wasn’t limited to:
Queuing up for water rations
Obtaining water from mountain streams and natural springs
Drilling of private boreholes by residents at home for a private water supply
Some residents (who could afford it) installed private rainwater catchment systems and harvesting tanks for private use, as well as grey water systems
Some residents recycling water from washing for use in toilets and gardens
Long Term Solutions
– Permanent Daily Water Use Reduction
According to climate.mit.edu: ‘… average daily water use in the city is between 700 and 800 million liters, about half what it was in 2014’
– New Infrastructure Developments
waterstories.co.za indicates that (paraphrased) new upcoming large infrastructure developments may involves the diversion of surplus water for storage in one of the large dams, which would add to water supplies and water capacity. However, this is dependent on rain
– Diversifying Water Sources
waterstories.co.za has a graphic that shows (paraphrased) Cape Town is currently reliant on surface water for 96% of their supply, and ground water for 4%
By 2040, there may be a target to get to 75% surface water, 11% desalination, 7% groundwater, and 7% reuse
– New Water Strategy Plan
Cape Town proposed an improved water strategy after the water shortage event was over, with goals for certain solutions to be implemented
Desalination may be a major option Cape Town tries in the future
climate.mit.edu notes that:
In consultation with researchers and scientists, [Cape Town] outlined a new water strategy in 2020 …
[It includes] diversifying water sources to include groundwater from wells and boreholes, recycled stormwater, treated wastewater, and household gray water, which could be reused for gardening and other applications that don’t require something clean enough to drink.
There are also plans for more desalination, controls on water use, leak reduction, and infrastructure investment
According to theconversation.com, Cape Town plans on trying augmentation options like desalination to increase their water capacity:
Cape Town is building a number of small desalination plants …
– Other Long Term Solutions & Plans
waterstories.co.za does a good job of summarizing other solutions and plans that Cape Town is looking into
Challenges Encountered In Implementing Solutions To Address The Water Shortage
There were a range of problems and challenges that Cape Town encountered, and some issues they still face today
Desalination in particular had cost related, and logistics related challenges as an example
Various proposed water sources such as desalination and waste water recycling had water quality issues
waterstories.co.za notes that (paraphrased) in 2018 there was a vision presented by the City Of Cape Town to diversify the water supply, however there’s already been various complications (which they outline in their report)
As a small summary of challenges (paraphrased):
– Ocean water that would be used for desalination contains chemicals (persistent chemicals pollutants), and none of the three emergency plants built in 2018 are still operational due to water quality issues
– Waste water that would be treated and reused contains chemicals (persistent chemicals pollutants)
– The full impact on biodiversity and ecology of drilling into groundwater aquifers might not be known
– The projected costs of the above options might be very high
What Water Supply Management Actions Were Taken Prior To The Shortage (Pre 2015)?
wikipedia.org lists some of the water strategy solutions that were implemented prior to 2015
Some of those solutions included, but weren’t limited to tariffs for those exceeding water usage limits, communal taps and toilets in some places, metering and monitoring irrigation on farms and making use of shared irrigation distribution schemes in some places, starting the construction of additional dams, increasing dam capacity, better managing water demand, reducing water leaks around the Cape Town area, and introducing by-laws for more efficient water fittings
Read more about these solutions in the wikipedia.org resource
Will Cape Town Have Another Water Shortage In The Future, & What Might Cause It?
General Factors That Could Lead To A Future Water Shortage
Some general factors might include:
– Water demand increasing along with population growth
– Per capita sustainable water usage limits not being followed
– Water supply capacity not being increased (to increase per person water limits)
– Water supply sources not being diversified (to more sources than just dams)
– Natural events like droughts happening again, or there being low or no rainfall to replenish dams and other water storage locations
Potential Impact A Changing Climate Might Have On Likelihood Of Future Droughts
Some reports indicate that a changing climate and further warming could mean the likelihood of a drought in the Western Cape area has roughly tripled, and further warming could increase this likelihood
This may only be a hypothesis at this stage though.
It should also be noted though that this is specifically for the Western Cape area – other areas around the world might have different factors at play.
Scientists … hypothesise that global warming has tripled the risk of a three-year dry run in the Western Cape province (insurancejournal.com)
… further warming of the earth from 1 degree above pre industrial levels, to 2 degrees above, would again make droughts three times more likely (on top of the original three times increase) (theconversation.com)
[Some] scientists believe that Cape Town will face more sustained droughts over the next 100 years because of climate change (climiate.mit.edu)
What Might Other Cities Learn From Cape Town’s Water Shortage?
Some of the lessons that other cities might learn from Cape Town’s water crisis might include:
– Consider how reliant they are on one water source for majority of their water supply
In Cape Town’s case, it was being reliant mainly on their dams
Diversifying to other water sources may help in this instance
– Considering how dependent they are on rainfall, and how affected by the climate and natural events they are for their water supply
Cape Town’s dams were reliant on rainfall to replenish, and a natural event in the form of a drought severely affected the water supply levels of the dams
Relating to the above point, diversifying to other water sources that aren’t as dependent on rainfall or impacted by climate or natural events may help
Desalination may be an example of a water source that isn’t as dependent or affected
Water recycling may be another
– Consider water supply vs water demand now, and in the future
Water supply involves having an adequate volume of water to meet the demand (withdrawal and consumption rates) on that water both now, and in the future
Increasing water capacity might help, but so might adding more water sources that can help augment supply
Also, projecting population growth and water demand increases for the future may help with future planning for water supply vs demand rates
– Have an emergency plan for natural events
In the event of a future drought or other similar event that could impact water supply, have an emergency plan in place to help manage it
Having clearly identified backup water supplies and clear water emergency plans might be examples
Also, having water restriction levels in place might be another
– Have systems for tracking progress on a city’s water management strategy, and keeping decisions makers and governments accountable
Having tools such as water level tracking (for volume and replenishment rate of water), and water quality tracking available on public websites might help keep decision makers and governments more accountable
– Be aware of what the sustainable daily or yearly per capita water usage limits are for a particular city
And, make sure this responsibility is being shared equally or relatively amongst residents, businesses, and farmers (irrigation in particular), if it isn’t being done already
This is also known as the equality of water distribution – is everyone getting adequate water supplies? Or, is it just big business and the wealthy? Everyone needs to be accountable/responsible for the water they use. A progressive water use tariff system or similar scheme could help. Consider the lifecycle of water use to determine where the most important water allocations should be directed first.
The sustainable per person limit changes depending on the individual city or town’s demand vs supply ratio, and their capacity to increase supply.
However, the World Health Organisation may suggest as the minimum daily water intake per person to be 50 liters per person per day [for sustainable consumption]
– Consider other sustainable water management solutions
Potential solutions may relate to water efficiency, water tariffs and taxes for the biggest users of water or excessive users of water, fixing leaks, and so on
Regulations to protect various water sources may be another solution
– Consider how to manage water hungry plants in the area
Such as removing/culling them
– Consider how a changing climate might impact the natural water cycle and the occurrence of natural events like droughts in the future
A changing climate may impact rainfall and weather patterns, and droughts obviously do too
Considering climate change as an issue may help indirectly address water risk and water security issues that could arise in the future
– Consider experimental ideas for water supply
Including shade balls, cloud seeding, harvesting water from the air, and towing icebergs from Antarctica
Water efficient farming with more water efficient use of irrigation water and use of new agricultural technology, such as night-time irrigation, mulching and concentrating water around the trees’ roots systems also helps
– Other potential solutions
waterstories.co.za has a good report that outlines all the key factors, issues and potential solutions to Cape Town’s water situation
Other Water Stressed & Water Scarce Cities Around The World