Toulouse. Did you know ? In times of drought, the Garonne is filled “like a swimming pool”
By Maxence Dourlen
Published on
For three weeks, a camera was installed by the Joint Syndicate for Studies and Development of the Garonne (SMEAG) on the roof of the EDF power plant Bazacle to monitor the flow of the river at Toulouse. The opportunity to recall the many operations that surround the 487 km of waterways from the Pyrenees to the Gironde estuary. Among her, son” to fill » daily, from July 1 to October 31.
30% of water consumed every day in the Garonne
During the entry into low water (minimum flow of a river), support is necessary so that the Garonne is not completely dry. Especially during the drought periods that we are going through.
Currently, the SMEAG injects 30% of the water present in the Garonne. This can go up to 40% as at the end of July when 18m3 were included every second in the river. This operation is intended to raise the water level, in particular to avoid any disturbance to the ecosystem that protects the Garonne.
“This hydrological drought is unprecedented. It’s rarely seen in 30 or 40 years! Maybe we won’t see that again in the decade…”
Reserves in the Pyrenees
To enable this upgrading operation, the Joint Syndicate for Studies and Development of the Garonne has significant reserves, including the Pyrenees and the lakes of the hydroelectric dams.
“We get supplies from lakes located between 1,500 and 1,900 meters above sea level,” explains Bernard Leroy, in charge of low water management at SMEAG. One can in particular quote the lake of Oô or the pond of Izourt. »
For 30 years now, the SMEAG has been in charge of replenishing the water of the Garonne when Mother Nature is confronted with drought.
“The flow of the Garonne is still activated by part of the melting of the Aneto glacier located in the Spanish Garonne, by snow, rain and groundwater. Climate change has been eroding its natural flows for more than thirty years and the replenishment of low water support waters has slowed down the erosion of these flows. »
An HD camera to observe the river
Imagined a few years ago by Bernard Leroy, the installation of the HD camera on the roof terrace of the EDF Bazacle power plant is now effective.
“This allows us to have a reading of the landscape and to make the link between the flow of the Garonne and the plant and animal communities. It is a very lively area that deserves to be watched. »
Daily points are made to measure the instantaneous flow, the water temperature or the part of the low water support as explained previously. This camera makes it possible to keep track and analyze all the periods, including the one we are currently going through between high temperatures and very low rainfall.
sociological studies
In parallel with the installation of this camera, sociological studies are carried out in conjunction with students from the University of Toulouse Jean-Jaurès (master’s degree in Environmental Policy and Social Practices). Tourists, students, athletes or even workers who come into contact with the Garonne on a daily basis are questioned to understand their relationship with the river and the perception they may have of it.
“We try to educate people to show the evolution of river landscapes with the animal and plant community”, adds Bernard Leroy. These studies have in particular made it possible to notice that the majority of people do not watch what is happening in the Garonne. “It’s a long-term project that we are carrying out in a heritage way,” he continues. The installation of several establishments (guinguette, restaurant, etc.) at the level of the EDF Bazacle power station gives an additional attraction to the river and to our studies. »
The issue of waste is also a central concern. “This webcam will allow us to understand more things”, concludes the engineer.
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