The bustling metropolis of Cape Town, South Africa, home to about 4 million people, is on track to run out of water and cut off its taps in May. Because of a years-long drought — believed to be partially caused by climate change — the city’s reservoirs are about to run dry.

AFRICA

 

Atlantic

Ocean

Indian

Ocean

Cape

Town

ANTARCTICA

 

The six dams that form part of the Western Cape Water Supply System, which supplies water to towns and provides irrigation water for agriculture.

Voëlvlei

10 MILES

17.3 percent

of capacity

Paarl

Wemmershoek

50.1 percent

Berg River

53.4 percent

Cape Town

Theewaterskloof

12.3 percent

Strand

False

Bay

Steenbras Upper

81.6 percent

Steenbras Lower

41.9 percent

Urban area

Cultivated

agriculture

Vine-

yards

The six dams in and around Cape Town that form part of the Western Cape Water Supply System, which supplies water to towns and provides irrigation water for agriculture.

Urban area

Cultivated

agriculture

Vineyards

AFRICA

 

Atlantic

Ocean

Indian

Ocean

Voëlvlei

Cape

Town

17.3 percent

of capacity

ANTARCTICA

 

Atlantis

Wellington

Paarl

Wemmershoek

50.1 percent

Cape Town

Berg River

53.4 percent

Cape Town

Int’l Airport

Theewaterskloof

12.3 percent

Strand

False Bay

The City of Cape Town uses approximately 64 percent of the total water supply, agriculture 29 percent, and other urban areas use about 7 percent.

Steenbras Upper

81.6 percent

Steenbras Lower

41.9 percent

Kleinmond

Atlantic

Ocean

10 MILES

The six dams in and around Cape Town that form part of the Western Cape Water Supply System, which supplies water to towns and provides irrigation water for agriculture.

Urban area

Cultivated

agriculture

Vineyards

AFRICA

 

Voëlvlei

Ceres

17.3 percent

of capacity

Atlantic

Ocean

Water levels are replenished from direct rainfall and rainfall runoff into the dams. Augmentation schemes, such as sea water desalination, only provide about 12% of the total available supply, while the low rainfall from 2017 accounts for 88% of the available water.

Malmesbury

Indian

Ocean

Cape

Town

ANTARCTICA

 

Atlantis

The City of Cape Town uses approximately 64 percent of the total water supply, agriculture 29 percent, and other urban areas use about 7 percent.

Wellington

Rawsonville

Paarl

Wemmershoek

50.1 percent

Bloubergstrand

Klapmuts

Berg River

53.4 percent

Berg River Dam, operational since 2007,has been the only major addition to the water supply system since 1995.

Cape Town

Cape Town

Int’l Airport

Theewaterskloof

12.3 percent

Strand

Theewaterskloof holds more than half of all the water in the system.

False Bay

Steenbras Upper

81.6 percent

Steenbras Lower

41.9 percent

Kleinmond

Atlantic

Ocean

5 MILES

Cape Town is still using in excess of 547 million liters of water per day. To avoid “Day Zero” — the day the taps are turned off — the daily usage needs to be reduced to 450 million liters per day.

[Analysis | On Day Zero, Cape Town will run out of water. It’s not the only city at risk.]

The loss of water can be seen most clearly with Cape Town’s biggest dam, Theewaterskloof. The reservoir now holds only 12 percent of its original capacity.

Theewaterskloof water levels on the

decline

Jan. 3, 2014

Jan. 17, 2016

Jan. 31, 2017

Jan. 16, 2018

Theewaterskloof water levels on the decline

Jan. 3, 2014

Jan. 17, 2016

Jan. 31, 2017

Jan. 16, 2018

Theewaterskloof water levels on the decline

Jan. 3, 2014

Jan. 17, 2016

Jan. 31, 2017

Jan. 16, 2018

Theewaterskloof in 2017. (Roger Bosch/AFP/Getty Images)

Here, the same lack of rainfall that has plagued the other reservoirs has been compounded by an explosion of urban growth. The reservoir feeds the bulk of the urbanized land area in Cape Town, where there are now far more people and businesses than there were decades before. But there has been no change in water infrastructure, causing the reservoir to run dry.

Water supply has not kept up with population growth

Cape Town in 1990 had roughly 2 million people, today the city of 4 million is expected to add another 200,000 people in the next five years.

Built up area

Area served by

Theewaterskloof Dam

1987

Atlantic

Ocean

Cape

Town

Cape

Town

Int’l

False Bay

2017

Atlantic

Ocean

Cape

Town

Int’l

Cape

Town

5 MILES

Water supply has not kept up with population growth

Cape Town in 1990 had roughly 2 million people, today the city of 4 million is expected to add another 200,000 people in the next five years.

Built up area

1987

Area served by

Theewaterskloof Dam

Cape Town

Int’l Airport

Cape

Town

False Bay

2017

Atlantic

Ocean

Cape Town

Int’l Airport

Cape

Town

5 MILES

Water supply has not kept up with population growth

Cape Town in 1990 had roughly 2 million people, today the city of 4 million is expected to add another 200,000 people in the next five years.

Built up

area

Area served by

Theewaterskloof Dam

1987

2017

Atlantic

Ocean

Atlantic

Ocean

Cape Town

Int’l Airport

Cape Town

Int’l Airport

Cape

Town

Cape

Town

False Bay

5 MILES

But all hope is not lost for Cape Town. The city’s efforts to conserve water so far, especially with limiting agricultural consumption, have pushed Day Zero from April to May, when the region’s rainy season starts.

[The effects of climate change will force millions to migrate. Here’s what this means for human security.]

The wettest seasons in South Africa

The Cape Town area is dependent on replenishing rainfall that falls in the winter months of May through July, while much of the rest of the country typically receives mostof its rain in the summer months.

ZIMB.

200 MILES

BOTSWANA

MOZ.

NAMIBIA

Pretoria

Johannesburg

SWAZI.

LESOTHO

SOUTH

AFRICA

Atlantic

Ocean

Indian

Ocean

Cape

Town

Fall

Winter

Spring

Summer

Feb.-April

May-July

Aug.-Oct.

Nov.-Jan.

Mar.-May

June-Aug.

Sept.-Nov.

Dec.-Feb.

April- June

July-Sept.

Oct.-Dec.

Jan.-Mar.

The wettest three month seasons in South Africa

The Cape Town area is dependent on replenishing rainfall that falls in the winter months of May through July, while much of the rest of the country typically receives mostof its rain in the summer months.

ZIMB.

BOTSWANA

MOZAMBIQUE

Windhoek

Gaborone

NAMIBIA

Pretoria

Maputo

Johannesburg

SWAZI.

Bloemfontein

Springbok

LESOTHO

Durban

SOUTH

AFRICA

Atlantic

Ocean

Indian

Ocean

Cape Town

Port Elizabeth

200 MILES

Fall

Winter

Spring

Summer

Feb.-

April

Mar.-

May

April-

June

May-

July

June-

Aug.

July-

Sept.

Aug.-

Oct.

Sept.-

Nov.

Oct.-

Dec.

Nov.-

Jan.

Dec.-

Feb.

Jan.-

Mar.

The reservoirs’ levels go up each year with the rainy season, and then down again during the dry season. So hitting the rainy season will likely save Cape Town from Day Zero for now.

Volume of water stored in the

Big Six dams is on the decline

Typically the water storage of the reservoirs decreases in the first months of the year, and increases again once the rainy season begins in May, but overall, the trend during the current drought is less available water reserves.

1 million

megaliters

Capacity for the six dams is 900,000 megaliters.

800k

2013

600k

2014

2015

400k

2016

2018

200k

2017

Water can only be extracted from the dams when storage is above 10 percent.

0

2014

Jan.

2015

Jan.

2016

Jan.

2017

Jan.

2018

Jan.

Volume of water stored in the Big Six dams is on the decline

Typically the water storage of the reservoirs decreases in the first months of the year (summer), and increases again once the rainy season begins in May, but overall, the trend during the current drought is less available water reserves.

1 million megaliters

Capacity for the six dams is 900,000 megaliters.

800k

2013

600k

2014

400k

2015

2018

2016

200k

2017

Water can only be extracted from the dams when storage is above 10 percent.

0

2013

July

2014

Jan.

2015

Jan.

2016

Jan.

2017

Jan.

2018

Jan.

However, with little rain expected this season — the volume has decreased year after year, which many climate scientists link to climate change globally — the city will likely run into the same issue later this year or early next.

[If the world builds every coal plant that’s planned, climate change goals are doomed, scientists say]

Accumulated daily rainfall at

Cape Town International Airport

Since 2015, the rainfall totals are significantly below the 40-year median.

2013

600

millimeters

2014

400

2015

2016

200

2017

0

Jan.

Mar.

May

July

Sept.

Nov.

Dec. 31

1977-2017

Accumulated daily rainfall at Cape Town International Airport

Since 2015, the rainfall totals are significantly below the 40-year median.

800

millimeters

2013

600

2014

median

400

2015

2016

200

2017

0

Jan.

March

May

July

Sept.

Nov.

Dec. 31

1977-2017

In response to its quickly depleting water supply, Cape Town has put in strict water restrictions on its residents. Each person is limited to using 50 liters — about 13 gallons — of water per day. To achieve this, the government recommends only flushing the toilet once a day and taking “stop-start” showers, in which the water is turned off while applying soap and shampoo.

What does 50 liters of water look like?

50 liters

(13 gallons)

Five-minute

shower

40L

Five toilet

flushes

45L

One dishwasher

load

29L

One laundry

load

70L

Daily drinking

water

3L

Daily hand-

washing water

2L

What does 50 liters of water look like?

50 liters

(13 gallons)

Five-minute shower

40L

45L

Five toilet flushes

29L

One dishwasher load

One laundry load

70L

3L

Daily drinking water

Daily hand-washing water

2L

If Day Zero comes, residents will be forced to collect their water at a few shared taps around the city, limited to 25 liters (about 6.6 gallons) per day. That’s equivalent to a three-minute shower, or three toilet flushes.

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About this story

City of Cape Town, Western Cape Government, Department of Environmental Affairs and Statistics South Africa. Land use data from South African National Biodiversity Institute. Satellite imagery for false color images of Cape Town from Landsat 5 and Landsat 8 via USGS EarthExplorer. Satellite images of Lake Theewaterskloof from Sentinel and Landsat via RemotePixel. Western Cape Water Supply System data from The Watershed Project. Accumulated rainfall and storage capacity from Climate System Analysis Group and University of Cape Town. Seasonal rainfall map from Climate Hazards Group InfraRed Precipitation with Station Data (CHIRPS).

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