Rouages: “Calculate the speed and volume of water to develop the best possible scenario”
Cédric Guillemin is a research technician at the Institut Agro in Montpellier. Since 2010, he has been responsible for maintaining the hydraulic hall, a facility used to train students and professionals. He tells us about his career dedicated to water in *Rouages*, the video series produced by the University of Montpellier. Action!
As this particularly hot early June begins, we watch with eager anticipation as water gushes into the channels of the hydraulic hall’s patio. In just a few seconds, it floods the 70 linear meters of this miniature network, surges over the duckbill weirs, and engulfs the pumps. Behind this little miracle of water is no grand wizard, but a man with a bit of a dowser’s touch. Cédric Guillemin is a research technician on the Agricultural Engineering team within the Department of Agro-Bioprocess Sciences at Institut Agro. He has been responsible for the smooth operation of this clear and unusual machinery for sixteen years now.
A one-of-a-kind installation
“The hydraulic hall was built in 1995, and I arrived in 2010 after a brief stint at INRAE and quite a few years of maintenance experience in the boating industry, ”says Cédric Guillemin shyly. “I do a little bit of everything: electrical work, mechanics, electronics…”In short, he’s the right man for the job to manage these 450 square meters of facilities, which are one-of-a-kind in France. First, there’s this outdoor canal located in the hall’s courtyard.“It’s a full-scale model of open-channel hydraulic structures found in agriculture in France and around the world,” explains the technician. “You can see small dams, screen modules, gates, weirs…”
Two large rooms flank this little oasis of coolness. In the first,there is a glass-enclosed channel called the Lirou autonomous channel.“It has an adjustable slope for studying, among other things, flow phenomena, and right next to it is the famous Pitot tube—which is very old but still works—for measuring the speed of the water. ” In the second room is the hall’s most recent installation: another fully glass-enclosed flume, 12 meters long and 1 meter wide, called the “Grand Canal Lez.”
Promoting Biodiversity
And here, too, the magic happens: a push from Cédric Guillemin and water floods the channel; another push, and suddenly the wave rises and stops, mimicking the phenomenon of tidal bores before receding.“I used to get yelled at for playing with water—now I get paid to do it,”the technician jokes. While the demonstration is certainly awe-inspiring, the usefulness of this installation is well established:“Right now, we’re working with the French Office for Biodiversity to study the effectiveness of fish passes in the migration of glass eels in the Petit Rhône,” explains Cédric as he activates a new control. “As you can see, if the gate is closed, with a flow rate like this, the fish can’t get through. We’re trying to calculate the right flow velocity so they aren’t blocked by the current.”
To this end, the main channel is equipped with various level sensors and ultrasonic sensors connected to recording devices; a laser beam system with high-speed cameras also allows for the observation of water flow phenomena. While the primary function of the hydraulic hall is to support research in fluid mechanics for agriculture and the environment, it is also a tremendous educational tool.
Committed to Education
More than 500 students in their initial training—mostly from the agronomy program or Polytech—pass through the courtyard and halls of the facility each year to carry out hands-on projects. It’s a task that this water management specialist particularly enjoys.“I make sure all the equipment is working so that the students can operate the valves, weirs, and pumps. The goal, for example, is to calculate the flow rate and volume of water to develop the best possible irrigation plan.”
The technician also guides the students in using various tools, such as the current meter, which, as its name suggests,“measures the speed of the current. With this device, we record several measurements and calculate an average speed,”or to trigger certain sensors. These hands-on exercises can also be conducted in the field, particularly at the Merle estate in Salon-de-Provence, where he also works“to install valves and sensors in order to optimize and automate gravity-fed irrigation.”
Serving Professionals
Professionals can also make use of the hydraulic testing facility.“Some come to continue their training in the field of water,”explains Cédric Guillemin; companies can also request services to calibrate equipment before it is brought to market. This diversity of clients and projects contributes to the professional fulfillment of this water enthusiast.
“I enjoy interacting with students and researchers, and working on all kinds of projects—from designing to conducting experiments, both here and out in the field. It’s a job that’s always full of surprises.” Some of which can take unexpected forms,“like a snake trapped in a manhole that I happened to come across and was able to free by installing a pressure sensor.” A man dedicated to water, ensuring that water continues to serve us for a long time to come.