Rouages: “If we keep this up, one day these aquifers will no longer be able to supply us with water”
Muriel Geeraert is a hydrogeology engineer at Géosciences Montpellier. In the Hérault or the Pyrénées-Orientales, she travels from drilling site to drilling site to collect the valuable data that will enable the Porous Media Transport Department to better preserve water resources. She explains this mission to us in the video series Rouages produced by the University of Montpellier. Action!
On this December morning, even the flamingos are shivering in the wind sweeping across the Prévost Pond in Villeneuve-lès-Maguelone. We meet Muriel Geeraert on the narrow strip of land separating the lagoon from the sea, a few hundred yards as the crow flies from the cathedral. Dressed in a thick coat, hat, and gloves, the hydrology engineer wears the broad smile of someone who is never indifferent to the beauty of the site and the light that bathes it.“It’s very cold today, but what a joy it is to work here,”she tells us as she pulls a chair and a folding table out of her van—items that will allow her to set down her equipment and, if the temperature warms up, to have a snack behind the container sitting there, the only shelter from the wind.
60 meters deep
While the term “drilling” might conjure up images of a relatively imposing setup for the uninitiated, we’re surprised by how bare the site looks—until Muriel draws our attention to the thin PVC pipes protruding from the ground.“There are eight wells in total, but this one allows me to process all the data I collect in the field. It goes down to 60 meters and is fully cased to allow the probe to pass through and take very precise measurements , ” she explains as she unfolds a winch about 2 meters tall. To make sure we don’t miss a single detail, we decide to equip her with microphones; the on-camera interview will come later.
A few minutes later, with the winch positioned directly above the well, the engineer pulls a slender metal cylinder out of a black plastic box:“Here’s the probe; I’m going to lower it down to the underground reservoir to bring up a small amount of water. I’ll measure its pH and conductivity on-site and send the rest of the samples to the lab for more detailed analysis.” Very quickly, Muriel Geeraert explains the importance of these procedures, revealing to us the fragility of the ecosystem around us.
Saltwater intrusion
“The problem here is the intrusion of saltwater into coastal freshwater reservoirs. Especially in the summer, we draw a lot of water for campgrounds and golf courses. The more we draw from the aquifers, the more seawater tends to seep in,” notes Muriel Geeraert. “If we keep this up, one day these aquifers will no longer be able to supply us with water. We’re having a major impact on nature,” laments the engineer, who initially trained in mechanical engineering and industrial automation and joined the Geoscience department in 2019 following the shutdown of the particle accelerator she had been working on. “It’s true that I’m coming from a very different background, and I’m learning a little more about geosciences every day. It’s such a vast field—I find it fascinating.”
As part of the “Transport in Porous Media” (TMP) unit at Géosciences, Muriel Geeraert is closely examining human impact at the Villeneuve-lès-Maguelone site—but that’s not all.“Every month, I take measurements at Pégairolles-de-l’Escalette, just above Lodève—another absolutely stunning site where we’re studying the effects of landslides in greater detail. I also go to Barcarès and Canet-en-Roussillon, and the last site is in Mallorca, though we don’t go there much anymore.”A lovely panorama of the region for this native Parisian who dreamed of coming to live in the South and appreciates above all the diversity of her activities, the sites, and the climate.
Practical exercises
And when she’s not out in the field, Muriel Geeraert spends her days in the lab.“We have to maintain the equipment and recalibrate it. We also have to process all this data; some of it is added to databases open to the general public.” Every year, she also participates in hydrogeology lab sessions where students can experience fieldwork firsthand.“I lead this workshop with Emmanuelle Petelet; we collect water samples and have the students perform analyses. It’s a really fun lab session, and it’s also an aspect of my work that I really enjoy!” Except when a snake decides to crash the party…