IIt is truly a terrible irony: for many of the 400 million people in sub-Saharan Africa who do not have access to even a basic water supply, there is probably a significant reserve in aquifers just a few meters below their put feet
Groundwater – the water stored in small spaces and fractures in rocks – makes up nearly 99% of all unfrozen fresh water on the planet. Across the continent of Africa, the volume of water stored underground is estimated to be 20 times the amount held in lakes and reservoirs.
The opportunity that groundwater provides to increase access to water is widely recognized, with more than half of the world’s population already believed to rely on it for drinking water.
When you add the ability of solar energy to power the necessary infrastructure and the fact that groundwater supplies are much more resilient than surface water during droughts, the potential for harnessing this water source to provide a clean and regular supply to communities in chronic need comes into play. provide. focus.
The opportunity that solar technology offers to increase the pumping of groundwater for drinking and irrigation will be discussed at the International Association of Hydrogeologists (IAH) this week. World Groundwater Congress in Davos, Switzerland.
Much of the debate centers on how best to deploy this increasingly affordable solar technology to unlock groundwater potential; not only in terms of drinking water, but also in terms of irrigating crops – unleashing the ability to address both water and food insecurity without the need for fossil fuels.
The IAH Congress comes at a time when the ability to map the availability of groundwater across the entire continent has never been greater. New understanding of African geology is helping local hydrogeologists predict which areas have the most potential for solar pumps and new, easy-to-use technology is being developed to help better assess groundwater quality.
Communities are helping to determine the most sustainable management models for water supply, while donors and governments are increasingly interested in the quality of rural supply chains.
Momentum is building, and with it comes the chance to bring meaningful, life-saving change.
The fly in the ointment, however, is the complexity that results from shifting from the hypothetical to the real world. There are two issues that will need to be at the center of the discussions in Davos if we are to ensure a sustainable path forward.
First is the potential for overuse. With the ability to pump large volumes of water comes the possibility of overexploitation and depletion of groundwater resources. This is an important point of concerns over parts of Asia, the Middle East and the US.
Second, we must not lose sight of the geological and environmental limitations of the technology to fully benefit from this opportunity. The ability to reach all parts of the region does not yet exist: about 30% of Africa’s rural population lives on ancient bedrock that may not be able to support the higher pumping rates required by large solar pumps.
A recent study by the organization I work for, the British Geological Survey, with partners from Paris-Saclay University, showed that geology is the key limiting factor for solar pumping, not the availability of sunshine.
I would urge caution among those who see this solar pump revolution as a panacea – those who focus solely on installing large-scale systems that extract large volumes of groundwater that can then be piped directly to homes or to farmers. what it needs.
Such programs can offer a balance between investment and impact, and as such attract increasing interest and financial support. So they must, because when they work, they will change the lives of many millions of people.
Next to the big projects, however, there should still be investments in small-scale use of groundwater for rural water supply, and for technologies such as hand pumps or low-yield solar pumps that are more suitable for the geology.
These smaller pumps can improve access to water for rural communities, while providing additional protection against overuse by adjusting pumping rates to the geology.
Where the geology is complex and yields from wells are low, small solar systems can pump throughout the day and store the water for domestic or productive use when it is actually needed.
We must measure our success in combining the power of solar technology with groundwater, not in terms of people helped, but in those left behind. This approach will help focus our minds on a comprehensive solution – to ensure sustainable solutions that improve access to clean drinking water for all.
Technological breakthroughs are exciting and progress is exciting. But it is essential that a focus on solar pumps does not distract from the most marginalized and vulnerable communities.
I want to invite everyone to see this “solar groundwater pumping revolution” in terms of equity. Through that lens, we have the chance to ensure that this precious resource is sustainably and equitably unlocked for all those still waiting for a safe and reliable water supply.
Prof Alan MacDonald is head of groundwater at the British Geological Survey and head of the IAH groundwater network for international development
