In 2001, the four countries crossing the Rhine, namely the Netherlands, France, Switzerland and Germany, joined a common body, the International Commission for the Protection of the Rhine (ICPR ), to restore the ecological continuity of the river, from its mouth in the North Sea in the Netherlands, to its waterfalls in Basel in Switzerland. In other words, the Rhine 2020 plan was to restore the free movement of migratory fish in the river, hampered since the 1950s by the proliferation of dams.
Symbol of this objective, the salmon had to return to reproduce in the Rhine. This concerted plan was to enable the four States to comply with a European directive adopted in 2000 – known as the “Water Directive” – which calls for restoring the good condition of all European rivers. Twenty years later, progress is timid.
To date, 600 obstacles have been dismantled or equipped with fish passes (dam crossing devices), so that migrants can go upstream of the river. Among them, in France, six large EDF dams were equipped between 2001 and 2019: Iffezheim, Gambsheim, Strasbourg and Gerstheim on the main course of the Rhine; Brisach and Kembs at the entrance and exit of the Old Rhine – the wild arm of the river, which runs parallel to the Grand Canal du Rhin, in the south of Alsace.
Cost of these improvements: 55 million euros, financed by EDF and the Rhine-Meuse Water Agency, a public institution under the supervision of the State. The Ill, a tributary of the Rhine, and its extensions to the Fecht and the Bruche have also been developed.
A strain of Rhine salmon
These efforts have produced results. In 2020, more than 200 adult salmon were counted at the Iffezheim observation station. To date, more and more salmon fry released into the river have come from salmon that have naturally returned to the Rhine.
Each year, fish farms take a few dozen large salmon returned from the North Atlantic to breed in captivity, before releasing their young into the river. In the 1990s, these nurseries came entirely from Loire salmon. Today, the latter only represent a quarter of reintroductions. A strain of Rhenish salmon therefore emerges slowly.
The Rhine Salmon association, in charge of monitoring the reintroduction of migratory fish, even observes dozens of wild nests in the Ill and its tributaries. Jean-Frank Lacerenza, director of Saumon Rhin, is optimistic:
“We are discovering them in an increasingly large area, which is a sign that the ecological continuity of the Rhine is progressing well. ”
But make no mistake, this ecological continuity of the river still comes up against serious obstacles, upstream from Strasbourg. Since the start of the program, the Netherlands, Germany and Switzerland have worked hard to meet their commitments.
For example, the Netherlands opened the Haringvliet locks – south of Rotterdam – in 2018, allowing migrants to enter the river at its mouth, at a cost of millions of euros. Germany has developed the networks of small tributaries in the region of Friborg-en-Breisgau, and Switzerland, its tributaries upstream of the Old Rhine. So many futile efforts in the face of the delay taken by France with regard to these enormous and impassable dams of Rhinau, Marckolsheim and especially Vogelgrun.
The movements of France
However, in 2013, France formally committed to equipping its large dams at Rhinau and Marckolsheim. But then she clearly dragged her feet and even attempted to tack. First in 2015, it defends a mobile fish passage project , avoiding the heavy equipment work of its three large dams. The idea? Capture the fish downstream of Rhinau, to transport them by boat upstream of Volgelgrun and release them in the Old Rhine, with a more favorable habitat than that of the Grand Canal. From there, the fish can continue their journey to Kembs, already equipped, then to Switzerland and therefore theoretically to the symbolic finish line of Basel. Outcry in the scientific world and among environmental NGOs. The project, considered too artificial, is retoked.
Then it’s radio silence. France is no longer putting forward any proposal. In December 2018, a coalition of 35 NGOs, Salmon Come Back, decided to seize the European Commission about French inertia. Convinced by their arguments, the institution reminds France of its obligations the following summer: it has no calendar or financing plan to present to implement its commitments.
Rhine Alive to bypass the dams
During a progress report by the International Commission for the Protection of the Rhine (ICPR) in the summer of 2019, France then put forward a new scenario that would allow it once again to avoid the development of the three dams . This time, it proposes to bet on its new plan “Living Rhine” of 40 million euros, carried by the Rhine-Meuse Water Agency, therefore the State, to reconnect the small arms bypassing the course of the river. main Rhine.
According to the French, these improvements would be enough to make the Old Rhine accessible by avoiding the three dams. A commendable project to restore suitable habitats for migrants, but which would in no way compensate for the need to bring fish upstream from Rhinau and Marckholsheim. Because the attractiveness of small rivers does not weigh much compared to that of the strong flow of the main course of the river.
It’s missed for Basel 2020, France is committed to 2040
It was therefore missed, for the “Basel 2020” objective, which aimed to restore the ecological continuity of the Rhine. Failure for which France’s delay bears all the responsibility.
In February 2020, during the interministerial meeting of the ICRP, which is held every six years, the Netherlands, Switzerland and Germany obtain in extremis a significant advance from France. The country is committed to the new Rhine 2040 plan on a schedule for commissioning the fish passes at Rhinau in 2024 and Marckolsheim in 2026.
Then, to everyone’s surprise, the government’s economic recovery plan announced in September 2020 includes an envelope of 80 million euros to develop the two dams. A timetable, a financing plan, the culmination of twenty years of procrastination is emerging.
For Jean-Franck Lacerenza, crossing the Rhinau and Marckolsheim dams makes sense:
“The circulation of fish in this section of the Rhine will give them access, with the help of a few other developments in progress, to all the rivers around Freiburg, to the suitable habitat. ”
The largest fish passes in France
EDF has started studies for the development of the Rhinau and Marckolsheim dams. Régis Thevenet, director of concessions and the environment at Hydroest, the hydraulic branch of EDF, explains:
“The fish passes of two dams should be quite similar but a little more complex than that of Strasbourg. There will be dozens of stepped basins that will pass above the factory to cross a water height of 13 meters. The big difference is that this time, you have to attract fish on both banks at the same time, then lead those arriving from the left bank to the crossing device located on the right bank, by a canal. We are targeting the end of the studies by the end of 2021. The two projects should start at an interval of six months. It will be the largest fishways ever designed in France. ”
The impossible passage of Vogelgrun
The Arlésienne of the Vogelgrun dam will remain, of a much older design and much more difficult to develop. For years, an ICRP working group has been looking for solutions. One would consist of raising the fish above the 13-meter dam, but the descent is problematic, warns Jean-Franck Lacerenza:
“We don’t know how to bring down the fish. Upon arrival, they would be lost and unsettled by the variations and would seek to retrace the opposite path, rather than continuing on their way. ”
The second hypothesis consists in making the fish pass under the dam through a tunnel of several hundred meters. Here too, the efficiency would not be there, continues the director of Saumon Rhin:
“There is a behavioral barrier for fish to enter such a long submerged tunnel. Furthermore, the variation in water temperature on both sides of such a pass would be too disturbing for the migrants who would become prey. ”
In the new Rhine 2040 Plan of the CIPR, no date is put forward for the completion of the Vogelgrun fish passage. Swiss rivers will therefore wait to receive migrants in the spaces they have created.
The issue of downstream migration left aside
When announcing the priorities of the recovery plan, Alsace Nature expressed concern that efforts are focused only on the development of the main Rhine to the detriment of the care of its annexes, where fish habitats are located.
In addition, current technologies do not allow fish to descend safely downstream from dams. Jean-Franck Lacerenza underlines:
“10% of fish die passing the turbines of each dam. Others are seriously injured. So on arrival, there is not much left. ”
Adult salmon moving up the Rhine die naturally after reproduction. But downstream difficulties affect their young, as well as the eels mainly. If France’s efforts to allow the return of fish are finally being felt, the problem of their downstream migration, that is to say of their descent towards the sea, therefore remains unresolved.
https://www.rue89strasbourg.com/saumons-circulation-rhin-france-200535