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The Telegraph
The Telegraph
Science
Harriet Barber

Hidden groundwater could save Africa from climate crisis

Locals in Kissa community in Adamawa fetch water from a stream. Dried up streams like this are a common sight in Kissa. During this period, locals are forced to dig the ground further to make way for a new and often temporary source of water. - WaterAid/Etinosa Yvonne
Locals in Kissa community in Adamawa fetch water from a stream. Dried up streams like this are a common sight in Kissa. During this period, locals are forced to dig the ground further to make way for a new and often temporary source of water. - WaterAid/Etinosa Yvonne

Most countries in Africa could survive at least five years of drought – and some could survive more than 50 years – if the continent’s groundwater reserves were tapped into, according to new mapping by the British Geological Survey and WaterAid.

If extracted with simple tools like boreholes and pumps, the groundwater could be “the world’s insurance policy against climate change,” the researchers said.

Groundwater exists almost everywhere underground in gaps within soil, sand and rock. In Africa, researchers say it would help communities cope with climate impacts like drought and irregular rainfall, and provide resilience after floods.

Tim Wainwright, the chief executive of WaterAid in the UK, said: “Our findings debunk the myth that Africa is running out of water. But the tragedy is that millions of people on the continent still do not have enough clean water to drink.  

“There are vast reserves of water right under people’s feet, many of which are replenished every year by rainfall and other surface water, but they can’t access it because services are chronically underfunded. Tapping into groundwater would ensure millions have access to safe, clean water no matter what the climate crisis throws at them.”  

Below are maps which chart current access to drinking water across Africa and drought resilience based on potential usable groundwater at national level. 

Africa water services map showing the percentage of the population using, at least, basic drinking water services, as measured by the WHO/UNICEF JMP in 2020. - BGS © UKRI
Africa water services map showing the percentage of the population using, at least, basic drinking water services, as measured by the WHO/UNICEF JMP in 2020. - BGS © UKRI
Africa groundwater storage map showing years of reserves of potentially usable groundwater at a national level, based on current usage plus current population using 130 litres per person per day, assuming no active recharge. - BGS © UKRI
Africa groundwater storage map showing years of reserves of potentially usable groundwater at a national level, based on current usage plus current population using 130 litres per person per day, assuming no active recharge. - BGS © UKRI

As groundwater is below the surface, it is more resilient to extreme weather than other water sources – such as lakes, rivers, streams and dams – and is largely protected from evaporation and less susceptible to pollution, the researchers said.

Every country south of the Sahara could supply 130 litres of drinking water per capita per day from groundwater, which would provide people with enough to drink, cook and wash with.

This calculation sees less than 25 per cent of the reserves used, giving it time to renew by rainfall or surface water. This means groundwater could provide a buffer against climate change for many years to come, even in the unlikely event that it doesn’t rain.

Africa groundwater storage map showing years of reserves of potentially usable groundwater at a national level, based on current usage plus current population using 130 litres per person per day, assuming no active recharge - BGS © UKRI
Africa groundwater storage map showing years of reserves of potentially usable groundwater at a national level, based on current usage plus current population using 130 litres per person per day, assuming no active recharge - BGS © UKRI

The experts said this includes countries such as Ethiopia and Madagascar, where only half the population have clean water close to home, and large parts of Mali, Niger and Nigeria.

The mapping has taken 15 years to complete and was led by Prof Alan MacDonald of the British Geological Survey. He called the groundwater a “climate-resilient water supply” and said making use of it is “very feasible”.

“It’s already being used in a lot of countries in Africa – about half of the continent’s population depend on it from wells and boreholes. It can be used a lot more. It’s really got a lot of untapped potential,” he told The Telegraph.

The technology needed to access it already exists – simple wells and pumps.

Women and children collecting water at the borehole on Chisi Island, Malawi - WaterAid/Dennis Lupenga
Women and children collecting water at the borehole on Chisi Island, Malawi - WaterAid/Dennis Lupenga

But investment is needed in expertise and maintenance, approximately 10 times more than is currently invested, WaterAid said.

Prof MacDonald explained: “You can’t just drill randomly, it’s not very successful in most places. You have to have the expertise to work out where the right fractures are in the rock to drill into it. We need to invest in local expertise, and then wells and pumps, and then in the maintenance of these.”

Prof MacDonald also cautioned that groundwater can be difficult to clean if it gets polluted – a risk considering it is often only 20 metres underground. 

“If you have a lot of fertiliser it can leach into the groundwater. In the UK and Europe we are strict about land management, where petrol stations can go for example. So similarly, for countries in Africa, [we need to] make sure the groundwater is protected,” Prof MacDonald said.

Cape Town's water crisis in 2018 saw citizens queue for hours to fill bottles as the taps ran dry – a scene that could become more commonplace - Dwayne Senior /The Telegraph
Cape Town's water crisis in 2018 saw citizens queue for hours to fill bottles as the taps ran dry – a scene that could become more commonplace - Dwayne Senior /The Telegraph

While groundwater in sub-Saharan Africa is largely underused, in other parts of the world – mainly in south Asia – overuse is rife. The report cautioned that it must be regulated to avoid mismanagement and over-extraction.

“Outside sub-Saharan Africa, groundwater is over-exploited. In much of northern India, Pakistan and Bangladesh, groundwater extraction is usually greater than the expected annual recharge from rainfall. During periods of drought, water supplies become unsustainable and may run out at a time when people need them most,” it said.

In Pakistan, for example, 94 per cent of pumped groundwater is for irrigation. The desire to further boost agricultural productivity to provide food for Pakistan’s growing population and export, has led to the overuse and deterioration of groundwater resources, it added. Coupled with urbanisation and the impact of climate change, Pakistan is now on its way to becoming one of the most water stressed countries in the world.

The new report, Groundwater: The world’s neglected defence against climate change, comes as heads of state meet this week at the World Water Forum in Senegal, West Africa.

The researchers concluded by calling for investment, which they say will be “key to securing life-saving sustainable and safe water and sanitation for communities living on the frontline of the climate crisis”.

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