A research project currently underway at the University of Quebec at Chicoutimi (UQAC) could well help Hydro-Quebec to better protect its facilities against major floods and floods.
Indeed, the establishment now has a mini spillway in its walls. Built at a cost of $1 million, this facility is in fact a reduced-scale version, at 1/40, of the La Romaine 4 spillway.
A team of researchers and students will use this installation to predict rock erosion in spillways.
“When we dump a large amount of water, there may be certain blocks in front of our spillways that are exposed and which may come off the rocky foundation. Work to strengthen the foundations could be done,” explained Annick Bigras, director of expertise, dams and infrastructures at Hydro-Québec.
Over the years, minor incidents have been observed in the facilities of the state-owned company. But it is hoped that the results of this research work will make it possible to establish a new model to predict this erosion.
“These are data that will be used for new works, but mainly for our current facilities,” added Ms. Bigras.
In Australia or South Africa, for example, structures have been weakened due to this erosion of the rock.
"The erosion penetrated the rock and the rocks separated, lifted and left with the water," said Ali Saeidi, professor-researcher in the department of applied sciences at UQAC.
Annick Bigras knows very well that such a serious situation can lead to a major problem. “If the phenomenon continued significantly for several days, the rock foundation could be destabilized and turn into multiple blocks. And ultimately, the spillways could tip over, be stripped, lose their foundations.
Hydro-Quebec has assured that its 700 dams, 60 power stations and 100 spillways are all safe, but nevertheless does not want to take any chances in the longer term.
“It's a phenomenon that is known and observed, says Annick Bigras. But today, we want to act diligently to ensure the sustainability of the safety of our structures.”
Australian researchers have already looked into the phenomenon. But at UQAC, many more parameters will be measured, which makes the project unique.
Among others, the effect of the opening of a spillway. “From the start, there is a lot of disruption. This aspect, it was necessary to monitor it, to measure it well, ”said Professor Saeidi.
And what is the reality in the joint between the concrete and the rock? “What is the pressure, the force between the block and the rocks? We have some conventional methods, but it shows, there is something that does not work. That needs to be determined, he added. In the joint there are many unknown parameters. There are a lot of unknown issues.”
Hydro-Québec helped finance the project. The recurrence of extreme meteorological phenomena is also an argument.
“When you think of climate change, you can think of larger spills. And there, we should act to ensure that our works are safe, ”clarified Annick Bigras.
The results could help hydropower producers around the world.
The research team is confident that they can establish a new model. To get there, it will take five to six years of effort.