Cape Town Is Almost Out Of Water. Could Australian Cities Suffer The Same Fate?

Cape Town Is Almost Out Of Water. Could Australian Cities Suffer The Same Fate?

The world is watching the unfolding Cape Town water crisis with horror. On “Day Zero”, now predicted to be just ten weeks away, engineers will turn off the water supply. The South African city’s four million residents will have to queue at one of 200 water collection points.

Cape Town is the first major city to face such an extreme water crisis. There are so many unanswered questions. How will the sick or elderly people cope? How will people without a car collect their 25-litre daily ration? Pity those collecting water for a big family.The crisis is caused by a combination of factors. First of all, Cape Town has a very dry climate with annual rainfall of 515mm. Since 2015, it has been in a drought estimated to be a one-in-300-year event.

In recent years, the city’s population has grown rapidly – by 79% since 1995. Many have questioned what Cape Town has done to expand the city’s water supply to cater for the population growth and the lower rainfall.

Could this happen in Australia?

Australia’s largest cities have often struggled with drought. Water supplies may decline further due to climate change and uncertain future rainfall. With all capital cities expecting further population growth, this could cause water supply crises.

The situation in Cape Town has strong parallels with Perth in Australia. Perth is half the size of Cape Town, with two million residents, but has endured increasing water stress for nearly 50 years. From 1911 to 1974, the annual inflow to Perth’s water reservoirs averaged 338 gigalitres (GL) a year. Inflows have since shrunk by nearly 90% to just 42GL a year from 2010-2016.

To make matters worse, the Perth water storages also had to supply more people. Australia’s fourth-largest city had the fastest capital city population growth, 28.2%, from 2006-2016.

As a result, Perth became Australia’s first capital city unable to supply its residents from storage dams fed by rainfall and river flows. In 2015 the city faced a potentially disastrous situation. River inflows to Perth’s dams dwindled to 11.4GL for the year.

For its two million people, the inflows equated to only 15.6 litres per person per day! Yet in 2015/6 Perth residents consumed an average of nearly 350 litres each per day. This was the highest daily water consumption for Australia’s capitals. How was this achieved?

Tapping into desalination and groundwater

Perth has progressively sourced more and more of its supply from desalination and from groundwater extraction. This has been expensive and has been the topic of much debate. Perth is the only Australian capital to rely so heavily on desalination and groundwater for its water supply.

Cape Town Is Almost Out Of Water. Could Australian Cities Suffer The Same Fate? Volumes of water sourced for urban use in Australia’s major cities. BOM, Water in Australia, p.52, National Water Account 2015, CC BY

Australia’s next most water-stressed capital is Adelaide. That city is supplementing its surface water storages with desalination and groundwater, as well as water “transferred” from the Murray River.

Australia’s other capital cities on the east coast have faced their own water supply crises. Their water storages dwindled to between 20% and 35% capacity in 2007. This triggered multiple actions to prevent a water crisis. Progressively tighter water restrictions were declared.

The major population centres (Brisbane/Gold Coast, Sydney, Melbourne and Adelaide) also built large desalination plants. The community reaction to the desalination plants was mixed. While some welcomed these, others question their costs and environmental impacts.

The desalination plants were expensive to build, consume vast quantities of electricity and are very expensive to run. They remain costly to maintain, even if they do not supply desalinated water. All residents pay higher water rates as a result of their existence.

Since then, rainfall in southeastern Australia has increased and water storages have refilled. The largest southeastern Australia desalination plants have been placed on “stand-by” mode. They will be switched on if and when the supply level drops.

Investing in huge storage capacity

Many Australian cities also store very large volumes of water in very large water reservoirs. This allows them to continue to supply water through future extended periods of dry weather.

The three largest cities (Sydney, Melbourne and Brisbane) have built very large dams indeed. For example, Brisbane has 2,220,150 ML storage capacity for its 2.2 million residents. 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 constructing a number of small desalination plants while anxiously waiting for the onset of the region’s formerly regular winter rains.The Conversation

Ian Wright, Senior Lecturer in Environmental Science, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook-icontwitter-iconrss-icon

 Get The Latest By Email

{emailcloak=off}

LATEST VIDEOS

The Rise Of Solar Power
by CNBC
Solar power is on the rise. You can see the evidence on rooftops and in the desert, where utility-scale solar plants…
World's Largest Batteries: Pumped Storage
by Practical Engineering
The vast majority of our grid-scale storage of electricity uses this clever method.
Hydrogen Fuels Rockets, But What About Power For Daily Life?
Hydrogen Fuels Rockets, But What About Power For Daily Life?
by Zhenguo Huang
Have you ever watched a space shuttle launch? The fuel used to thrust these enormous structures away from Earth’s…
Fossil Fuel Production Plans Could Push Earth off a Climate Cliff
by The Real News Network
The United Nations is beginning its climate summit in Madrid.
Big Rail Spends More on Denying Climate Change than Big Oil
by The Real News Network
A new study concludes that rail is the industry that's injected the most money into climate change denial propaganda…
Did Scientists Get Climate Change Wrong?
by Sabine Hossenfelder
Interview with Prof Tim Palmer from the University of Oxford.
The New Normal: Climate Change Poses Challenges For Minnesota Farmers
by KMSP-TV Minneapolis-St. Paul
Spring brought a deluge of rain in southern Minnesota and it never seemed to stop.
Report: Today's Kids' Health Will Be Imperiled by Climate Change
by VOA News
An international report from researchers at 35 institutions says climate change will threaten the health and quality of…

LATEST ARTICLES

Can Sea Water Desalination Save The World?
by CNBC
Today, one out of three people don’t have access to safe drinking water. And that’s the result of many things, but one…
The Rise Of Solar Power
by CNBC
Solar power is on the rise. You can see the evidence on rooftops and in the desert, where utility-scale solar plants…
World's Largest Batteries: Pumped Storage
by Practical Engineering
The vast majority of our grid-scale storage of electricity uses this clever method.
How Wildfire Smoke AfHow Wildfire Smoke Affects Pets And Other Animals
How Wildfire Smoke Affects Pets And Other Animals
by Stephanie Laura Bond, et al
Catastrophic fires across the globe are increasing in both frequency and magnitude. The bushfires in Australia, fuelled…
5 Ways Families Can Help Tackle Climate Change
5 Ways Families Can Help Tackle Climate Change
by Greg McDermid, et al
While many climate solutions require leadership from governments, we also need changes within regular households, which…
Geo-engineering Could Make Poor Countries Richer
Geo-engineering Could Make Poor Countries Richer
by Tim Radford
There is still no certainty that geo-engineering could save the world. But, paradoxically, if it did work it might…
Worst Marine Heatwave On Record Killed One Million Seabirds In North Pacific Ocean
Worst Marine Heatwave On Record Killed One Million Seabirds In North Pacific Ocean
by Tim Birkhead
A common guillemot colony on the Farallon Islands, California. Duncan Wright/Wikipedia, CC BY-SA The common guillemot…
Nuclear Power Cannot Rival Renewable Energy
Nuclear Power Cannot Rival Renewable Energy
by Paul Brown
Far from tackling climate change, nuclear power is an expensive distraction whose safety is threatened by wildfires and…