French geologist Alain Gachet says new water divining technique could alleviate drought all over the world

“And Moses lifted up his hand, and with his rod he smote the rock twice: and the water came out abundantly, and the congregation drank, and their beasts also.” Numbers, chapter 20, verse 11.

Alain Gachet is a modern-day Moses. His hair is biblically white but unbiblically short. He has produced water “abundantly” from the rock in some of the world’s most pitiless deserts – Darfur in the western Sudan, northern Kenya and now in Ethiopia.

Mr Gachet is not a prophet but a French geologist. His instrument is not a rod but radar images of Earth taken from satellites. He has devised a computer programme which can unscramble surface obstructions and expose water “shining” far underground.

Mr Gachet, 65, says that his process (metaphorically) “peels away the rocks like an onion” and reveals unsuspected underground rivers and aquifers of fresh water lying hundreds of metres below the most drought-stricken parts of the planet.

In 2013 his method located a lake bigger than Windermere up to 300 metres below the parched northern tip of Kenya. He has helped NGOs locate the sites for scores of wells in Darfur in southern Sudan.

He has recently helped US government engineers to discovered immense water resources far below the deserts of northern Ethiopia. This finding has been little publicised, until now, partly because the Ethiopian government wants to avoid competing claims on the resource from nearby groups, including the extremist al-Shabaab.

Just like the water-divining activities of Moses in Numbers Chapter 20, Mr Gachet’s work can lead to political arguments, jealousies and misunderstandings. He sometimes feuds with relief charities and with Unesco but his work – literally ground-breaking - has been praised, and his expertise frequently sought, by the US government and the United Nations.

He is less well-known in his native France and in Europe – although he has recently received France’s highest civilian honour, the Légion d’Honneur.

Mr Gachet has now written a book which describes his extraordinary career. He hopes the book – “L’Homme qui fait jaillir l’eau du désert” (The man who makes the desert gush with water) – will help to lift his work to a new level.

“Water – or the lack of water – in Africa and the Middle East is the ultimate source of almost all the terrible problems that we see in the news today,” Mr Gachet told The Independent. “Why are migrants pouring into Europe from Africa? Because drought means that their animals are dying and their families are dying and they have no choice but to seek a living elsewhere.” He also believes drought has contributed to conflicts across the Middle East.

“Similarly, the failure of crops from Tunisia to Syria, caused by shortages of water, is largely responsible for the conflicts which have spawned Daesh (Isis).”

And yet, Mr Gachet believes – and has proved – that some of the most barren and impoverished territories on earth sit atop immense natural reservoirs of water. This “deep water”, he says, is constantly replenished and 30 times larger than the contents of all the world’s rivers, lakes and man-made reservoirs.

The only problem is that the “deep water” lies very deep indeed– almost as deep as oil. To extract it is a very expensive business and, since “water is not a market-quoted commodity”, there is no proper commercial infrastructure for finding it and pumping it from the bowels of the earth.

Mr Gachet – once a prospecting geologist in the oil, gold and diamond industries – believes that his invention could be the basis for a global programme, possibly funded by the World Bank and the UN, to defeat endemic drought in Africa and the Middle East and Central Asia.

He and a colleague operate his business from Tarascon in the Rhône Delta. He is, however, far from being an armchair explorer.

Indiana Jones-like, Mr Gachet pursues his scientific findings to the ends of the earth, as a film documentary on France 5 TV will show next month. “My philosophy has always been that you must have your eyes in the sky and your feet in the mud – or in the sand,” he told The Independent.

Mr Gachet was present in person in July 2013 when successive jets of water from 120 metres, 200 metres and 330 below the ground – proved his assertion that there was a lake the size of Windermere below the Turkana desert in the northern extremity of Kenya.

He has exposed himself more recently to the predations of the Al-Shabaab jihadists from Somalia to supervise exploratory drilling funded by US Aid in northern Ethiopia.

“The drillers are the real heroes of the story, facing Al-Shabaab terrorists scavenging and taking hostages,” Mr Gachet said. “My process allowed the drilling teams to work quickly and accurately, improving their security as they did not spend useless time drilling blindly.”

The exploration proved the existence of a “Karamara East Aquifer”, 200 kilometres long and 50 kilometres wide, with water stretching to 700 metres below the surface.

The US geological service in a recent report said that the aquifer could contain up to 30 billion cubic metres of water ”improving the livelihoods of the nearly one million people living in this water-scarce area, most of whom live in poverty.”

Mr Gachet devised his system, which he calls “watex”, in 2002. He is improving it all the time. Radar scans from satellites, or aircraft, can detect humidity up to 30 metres below the ground. The problem is that the humidity is often masked by surface obstructions, from houses to boulders.

Over two years, Mr Gachet invented a mathematical algorithm which, fed into a computer, strips away the surface interference and reveals the water below. “Just like the Hubble telescope can look further into deep space because it is outside the earth’s atmosphere, my process allow us to see deeper into the ground,” Mr Gachet said.

“When you apply the watex programme to radar scans, the water glows. It really glows. You can see the shining veins of the edges of aquifers and underground rivers.”

Although radar can only detect water up to 30 metres deep, the “water-glow”, if matched with geological surveys, can infer the presence of lakes up to 700 metres or more below the surface.

The watex system has already helped locate new temporary wells for refugees in Darfur and elsewhere. Its real benefit, however, could be to make drought a thing of the past – climate-change or not – in some of the most desiccated parts of the planet.

NGOs operating in the third world are in the business of solving emergencies and crises; they could see expensive long-term “solutions” as a distraction from immediate misery. Hence, in part, Mr Gachet’s occasional feuds with aid organisations.

He wants now, however, to make the case for a long-term watex-led international programme to conquer, or at least diminish, drought. As a first step, he is looking for an English-language publisher for his book.

“Over a billion people have no easy access to drinking water,” Mr Gachet said. “Something like 1.8 million children die each year from diseases linked to drinking bad water. In another half century, there will be 5.5 billion – two thirds of the population of the planet – living in a state of severe water-shortage.”

And yet, he insists, there is plenty of water available if we only look – and drill - downwards.