We find water in granite

In Paraguay, drillers stop when they hit granite. In Sweden, driller know they have to drill in granite. So what's the difference?

Sweden has a 150 years long history of documented wells in granite. Moreover, in Sweden there is granite everywhere, so drillers, hydrologists and geologists have been forced to figure out how to extract water from that crystalline rock. The famous geologist Erik Nordensiöld described a long list of successful case studies of drilling for water in basement rock as early as 1896.

Since then, technology has advanced and thanks to our Resonance Acoustic Profiling, we are now able to see the underground fissures that are likely to be filled with water.

Fissured granite

San Bernardino is an example in Paraguay where we did the impossible: in an granite area and on a small sidewalk, we did a 3D image to locate a spot with a distinct underground fissure system. The driller extracted more than enough water to cover the household needs of the client - a great satisfaction!

In La Colmena we had more space, about 1 hectare, to find the best spot to extract crystalline water from the granite. That could however have turned out bad, not because of the hydrogeology, but because of prejudice. We didn't expect granite, which was the rock that we encountered at 50m depth. Paraguayan geologists learn that "there is no water in Paraguayan granite" so the geologist's advice was to stop the job.

But according to our experience around the world, there are water filled fractures in granite. The trick is to know where they are and manage to hit that target while drilling.

I was confident that we had found those fractures. To double-check I had another look at the survey imagery, went back to check the spectrum of the signals and verified the radiometric analysis. All indicators were good. So I took a deep breath and told the driller to proceed.

Some hours later and 100m deeper I got another phone call, joyful this time: they had hit water, in the granite, and it was crystal clear!

Hydrology is tricky because you can't see with your eyes what's underground. It's all about interpreting signs and signals. And when false theories become certainty, that same theory gets elevated to the truth. And what happens then? In this case, the false belief that there is no water in granite conditions drillings so that drillers stop when they hit granite. That results in the Paraguayan granite being unexplored, so the false theory doesn't get a fair chance to be proven wrong.

There are wide areas where the underground is predominantly granite, like in San Bernardino. Most people there think that it's impossible for them to get good quality water from their own well. I am ready to take on the challenge of proving them wrong. Let's get good water for San Bernardino now!

Written by Marie Aichagui