Situated about 800 metres from the coast on the Franco-Italian border, the spring is fed from the Alps at a rate of 100 litres a second. A steel pipe has now been fixed in place which brings the fresh water to the surface.

"This technological innovation opens up considerable opportunities for countries with water shortages because some of them also have fresh water supplies situated off their shores," said Paul-Henri Roux of the company Nymphea Water.

"The water contains less than a gram of salt per litre compared to 38 grams in the Mediterranean. It is slightly brackish but is perfectly good for agricultural use and mixed with water from other sources it is drinkable too," he said.

The cost of the three year project was four million euros, and its main difficulty was isolating the source from the salt water around it, according to Roux.

For the moment the fresh-water bubbles free on the surface for the use only of passing yachts, but there are plans to instal a pipeline to bring it to shore for commercial exploitation.

TERRA.WIRE