Analysing a water shortage event can give us some useful information on how to plan for, deal with and possibly reduce the likelihood of a similar event in the future.
In this guide, we take a closer look at the Cape Town water shortage as a case study.
Summary – Cape Town Water Shortage Case Study
The Cape Town water shortage event involved a decrease in city water supplies/resources to critical levels, which led to significant water usage restrictions in the city
It was mainly caused by a severe drought (what is reported to be a one in 300 year rare and extreme event) limiting rain water levels to the city’s dams, although there were other causes that contributed to the event too.
Cape Town was reliant on rain and their dams to provide fresh water resources for the city (they did not diversify their water sources, or have water sources like desalination and water recycling that weren’t dependent on the climate – 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)
Some sources indicate the Cape Town government and water management planners did not plan for the drought because it was ‘an out of the norm event’.
Although, there were things being done to manage water supplies prior to the shortage.
Population increase, which led to water demand increases, was also a factor, along with the possibility that a changing climate and changing weather patterns had something to do with the drought event.
Other factors are listed in the guide below.
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
A few of the significant effects of the shortage were water restrictions to the municipal supply of water, residents having to significantly decrease their daily water usage, and agriculture and businesses also decreasing their daily water usage.
There were several other major and minor effects created by the water shortage (listed in the guide below)
The water shortage was eventually alleviated (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) in large part because of water restrictions imposed (which helped preserve a minimum level of water supply), and also because of rainfall restoring dam water levels
Solutions like desalination and water recycling were costly and had logistical challenges though.
Cape Town is now looking to avoid a future similar water event.
What Was The Cape Town Water Crisis/Water Shortage?
It was a shortage in the municipal dam water supplies (there was 6 of them in total) to most notably the City Of Cape Town (and the Western Cape region)
The peak of the crisis was around mid 2017 to mid 2018, although dam levels had been slowly decreasing since 2015.
What Caused The Water Shortage?
The Western Cape Town region water supply system heavily relied on/was dependent on rainfall
A severe drought (lack of rainfall for a period of time) was the main cause of the shortage – it was reported to be about a one in 300 year rare event.
It is possible this drought was a result of, or connected to climate change weather patterns
There was also a failure to account/plan for the drought event (by government and planners) because it was so far out of the norm
Population increase (along with demand increase) also had a major role
Other possible causes of the shortage were:
Pre-existing supply and demand issues (the population of Cape Town that was dependent on water supplies had grown significantly in a 20 years period – increasing demand for water),
Government failure (through lack of planning and implementation, fighting between opposing political parties, withholding of funds by one party to sabotage the other, increasing debt, corruption, and other factors) to address the potential for a shortage.
Invasive plant species around the dam that are water hungry are also thought to have had some impact on declining water supplies (sucking up to 7% of the water supply by some estimations)
What Was The Impact/What Happened As A Result Of The Water Shortage?
Some of the effects were:
Reservoir water levels in 6 major dams (that supplied the city) decreased
Water supply levels in the dams decreased from about 70% to 15 to 30% of total supply quantity at the lowest period of the shortage
Level 7 water restrictions were imposed
Municipal water supply had to largely be turned off, and residents had to severely decrease daily water usage (this partly involved queueing up for water rations)
Agriculture and businesses in the region also had to decrease daily and overall water usage
There were a range of other impacts of the water shortage that affected the economic sector (agriculture, tourism), the poor/those below the poverty line, public health, civil unrest, unethical water sales behavior, occupational health and safety, childcare and the risks involved with fires.
Read more on the impacts at wikipedia.org
One of the major consequences of dams reaching too low of a level (around 13%), is Day Zero, where municipal water supply taps and water sources have to be shut off completely
How Cape Town Addressed The Water Shortage
As of September 2018, the worst of the water crisis looked to be over with dam levels reaching around 70% of total capacity (up from around 15 to 30% in mid 2017 to mid 2018)
This rise in dam levels was mainly achieved via the water restrictions imposed and followed (by residents, farmers and businesses), and from the increased rainfall
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
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)
Eventually, towards the second half of 2018, Cape Town decreased water restrictions as dam level rose with increased rainfall
What Other Options & Solutions Did Cape Town Explore To Address The Water Shortage?
Attempts were made to increase supply, and decrease demand of water:
Buying additional water supplies from other water reservoirs in other regions
Looking into water desalination plants (plans eventually abandoned)
The above options turned out to have logistical challenges, and were costly and complex to implement.
Another water user association eventually some of their dam water supplies be transferred to the Cape Town supply for free.
Other options pursued were:
Regulation of common pooled water resources
Enforcing water reductions and ensuring compliance of these reductions via various methods
Increasing water tariffs
Bringing in bottled water supplies to the city
Residents obtained water from mountain streams and natural springs
Drilling of private boreholes for water supply
Installation of private rainwater catchment/harvesting tanks for private use
Encouraging water efficient farming with more water efficient use of irrigation water and use of new agricultural technology (night-time irrigation, mulching and concentrating water around the trees’ roots systems also helps)
What Was Being Done Prior To The Shortage (Pre 2015) To Preserve Water Supplies?
Some of the management options that were tried were:
Water tariff systems were in place (to tariff those who used over their water limit)
Communal taps and toilets were in place for some settlements
Farmers and their irrigation were metered and monitored, and some had shared irrigation distribution schemes in place
Extra dam construction was commenced
Increase of existing dam supply/capacity limits was implemented
Water demand management was commenced
Water leak rates in the Cape Town area were reduced
By laws were introduced for more efficient water fittings
What Might Cause Another Water Shortage In Cape Town?
Potential Contributing Factors To A Future Shortage
Unless total water supply capacity is increased in the future, future water shortages will be dependent on future daily water usage totals, and above average rainfalls in the area (could be influenced by a rising temperature and climate change), to ensure dam levels don’t reach levels that impose more restrictions and shortages
Population growth, along with a lack of tariffs, penalties and regulations for high volume water users could compound the issue
The government needs to find a way to augment (increase) future water supply to be able to deal with increased demand and lack of rainfall (whether that is via tariffs or other schemes to fund future water augmentation)
Additionally, according to theconversation.com, Cape Town plans on trying augmentation options like desalination to address their small per person water supply storage capacity compared to other cities around the world:
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
Cape Town is building a number of small desalination plants to deal with this
Other Notes When Planning For A Future Shortage
Scientists also hypothesise that global warming has tripled the risk of a three-year dry run in the Western Cape province (insurancejournal.com)
Other sources indicate that 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)
It should be noted that this is specific to the Cape Town area – different areas might be more or less dependent on rainfall and have different total water capacity supplies per capita in their city or region i.e. there are different variables at play in each place
What Can Other Towns, Cities & Regions Learn From The Water Shortage?
Some things they might learn might be:
Consider how reliant they are on rainfall to service and fill the municipal water supply
To account and plan for rare weather and rainfall events
To consider population growth in a city, and compare it to water supply – make sure demand and supply is in balance
To have sufficient water supply capacity – increase total water supply capacity if necessary
Monitor each political party to make sure they are both working towards solutions and action that safeguards the population against future water shortages
Consider water usage limits (daily limits) for residents, businesses, and farmers (irrigation in particular), if it isn’t being done already
Work with business and the industrial sector, and the agricultural sector, to make advancements in water efficiency
Consider a tariff or water tax system for those who use the most water
Consider fixing old and leaky water infrastructure pipes and water delivery or transport systems
Consider a water restriction emergency plan with increasing levels of water restrictions, and what happens at each level
Consider how climate change might impact future rainfall and weather patterns – impose solutions to address climate change if necessary (the increase in global average surface temperature and other warming)
Consider any factor that might be unnecessarily draining the existing water supplies e.g. plant species that are water hungry
Consider where there might be conflicts of interest in bringing in new water supply augmentation policies and technology e.g. ask about the connection between a politician and a water desalination supplier, and whether there is a conflict of interest there.
Ask what the most cost, social and environmentally effective short term and long term solutions are for the entire city or region
Consider 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. If a progressive water use tariff system or similar scheme needs to be introduced – then it does. Consider the lifecycle of water use to determine where the most important water allocations should be directed first.
Consider how much of the total water supply is polluted or contaminated and unfit for human use
Consider how much water coal and fossil fuel energy plants use for cooling purposes
Consider that the World Health Organisation recommends as the minimum daily water intake per person to be 50 liters per person per day [for sustainable consumption]
Consider experimental ideas for water supply including shade balls, cloud seeding, harvesting water from the air, and towing icebergs from Antarctica
Which Other Cities Might Be Most Likely To Run Out Of Water/Experience Water Shortages In The Future?
New Delhi and Hyderabad in India, Beijing, among other Chinese cities, Jakarta, Singapore and Sydney in the Asia-Pacific region, Brussels and Rome in Europe, along with San Francisco and the Manhattan area in the U.S. are some of those with relatively high water risks
Sao Paulo, Bangalore, Beijing, Cairo, Jakarta, Moscow, Istanbul, Mexico City, London, Tokyo and Miami are also cities identified as being at higher risk of running out of water in the future
It should be noted some of these cities have been working on addressing that water risk to various extents.