(Orléans) They monitor the pipes, sewers, dikes and rivers: drones, whether they fly, float or roll, have gained their place in water management in France, replacing humans in certain tasks dangerous.
Alban Chesneau, helmet on his head, lifts a manhole cover with a pickaxe. The leader of In-R grabs the drone by its protective cage and drops the craft into the conduit.
All lights on, the drone sinks, the walls of the manhole returning the high pitched sound of the four small engines. The technician now relies on his camera to navigate the Orléans sewerage network, in central France.
“With a single opening, we will be able to inspect between 150 and 200 meters depending on the nature and the cleanliness”, explains the pilot based in Saint-Herblain (west).
The obstacles can be numerous and the piloting difficult in confined spaces: cobwebs, roots, water level… The inspection can be limited to about fifty meters per descent.
“But with regard to the number of batteries on the site, we will be able to carry out an inspection panel which rotates between 750 meters to one kilometer per day”, adds the man with the remote control. “Without having to descend from humans into the network. ”
Not far from there, Jean-François Bramard, founder of the Cambulle company in Bouc-Bel-Air (south), is also preparing to descend his aircraft, a rover.
“We need an agile machine, with quite specific properties that allow it to move in places where there are stones, bottles, roots, a multitude of objects. The goal is to be able to take reconnaissance images to plan work, ”he explains, checking that the wheels are articulated in all directions.
For the French giant Suez, which manages part of the Orléans sewerage network, small remote-controlled vehicles are a real asset.
“These techniques are fully operational. This year, we carried out 3 kilometers of inspection in Orléans, on structuring networks that it was essential to inspect. […] Concretely, it makes it possible to know the state of the heritage under the cities ”, welcomes Alexandre Ventura, responsible for innovation, diagnostics and robotics at Suez.
Risks avoided
“These are hours of underground work […] and risk-taking avoided, ”he says with satisfaction.
These benefits are not limited to sewers. Drones are used in almost all areas of water management, such as dike monitoring.
“During an inspection, qualified people auscultate on foot. By using a drone with a camera, we have access to interesting points of view to which people on foot do not have access, ”says Jordan Perrin, engineer at France Digues, the association of dike managers.
Adding a thermal sensor can also help identify leaks. Lidar (laser telemetry) also makes it possible to obtain a fine topography of the area.
“Before, it was a helicopter. It costs a lot less now, ”appreciates the engineer. “And we can now also use aquatic drones for all the bathymetry. ”
This is the radius of ADCPro. The floating devices of the company based in Breuil-en-Vexin (Paris region) thus monitor rivers, lakes, ports and water bodies. She works for regional environmental departments, water agencies, laboratories and even Suez and Veolia.
Its monohulls or trimarans, which can carry up to 25 kilos of instruments, are used in multiple missions: “mapping the seabed”, gauging to obtain “instantaneous flow”, withdrawals, details its president Dany Engel.
Small orange boats also measure various parameters (chlorophyll, ammonium, nitrates, pH, conductivity, temperature, turbidity, etc.) in places difficult to access for a crew. “The hydrojet engines (water propulsion, Editor’s note) allow you to move through algae or port areas without being disturbed by the ropes”, appreciates the manager.
Here again, with an obvious gain. “The interest is also to have no one on the water, because there is a risk of drowning”, he continues. “Normally, there should be three on a boat: a pilot, a technician and a supervisor. People trained and sometimes at length. We just need a pilot. And losing a drone is okay, losing a man isn’t. ”