2023-08-01 12:00:00
Two years ago, between July 13 and 15, Belgium was hit by the worst natural disaster in its history: floods that killed 39 people and caused significant material damage. Very quickly, scientists and naturalists pointed to the artificialization of waterways which took place on a massive scale in the 1960s and insisted on the need to give rivers a more natural course to limit future tragedies.
The IRM estimates that floods of this magnitude occur on average once every two hundred years, but a study published in August 2021 by 39 researchers concludes that this type of disaster is likely to increase due to the global warming. A model established by a climatologist from the University of Liège even shows that floods comparable to those experienced by Belgium in 2021 might be repeated in ten to twenty years.
“The observation is as follows: we are in a mess and we must take measures to avoid new disasters! Renaturalizing the rivers, giving them their natural sinuous shape and giving them more space is part of the solutions”, explains Arthur Timmermans , biologist and eco-pedagogue at the Cercle des naturalistes de Belgique, specializing in hydromorphology.
“In the 1960s, the majority of waterways were deprived of their natural meanders for practical reasons. They were channeled, linearized to limit erosion and all the water was brought back into a single channel to promote transport by boat, gaining living space and depth. But when you have more concrete, you get a gigantic runoff and the masses of water flow much faster from the top of the river to the bottom”, specifies- he. “The current state of our rivers is due to an error of the past. The valley bottoms and their biodiversity are very impacted by this management. Now, the whole challenge is to know how to reverse”, adds Arnaud Laudelout, biologist and member of the studies department of Natagora.
According to a Bilogist from Natagora, Wallonia is paying the price for a lack of ambition that has lasted for a long time. ©JC Guillaume
In two years, various actions have been carried out. “We did a whole series of things. Three projects carried out by the administration received fairly substantial budgets,” says Walloon Environment Minister Céline Tellier.
Among them, the creation of a temporary immersion zone in Saint-Remy (Virton), aimed at preventing floods in the catchment area of the Chiers; the re-meandering of the Brouffe with the aim of slowing down the flood wave upstream of the village of Mariembourg and the creation of a temporary immersion zone on the Wamme upstream of the villages of Hargimont, Harsin and On (Marche-en -Famenne) and Jemelle (Rochefort). A call for projects was also launched last year.
“We received around thirty files from municipalities, provinces or associations and we selected seven of them for a total budget of 6.4 million euros. We also have an important project concerning the open-air restoration of a river which was affected by the floods in Limburg. These are projects of different natures but which all have the objective of recreating a river that is more natural, more alive and which leaves the possibility for the water to occupy more space. It’s the best way to fight once morest floods and drought. It’s a cultural change that we’re trying to bring regarding: moving from rectilinear, mono-objective and centered on the human experience to a river livelier,” continues Ms. Tellier.
Conflicts of actors and uses
But the renaturalization of Walloon waterways is coming up once morest material and human obstacles.
“To re-meander watercourses, we have to look for spaces that are used. Either we find nature, lawns or forests; or we find houses and cultivated fields, which has the consequence that “sometimes you have to relocate people. This can lead to conflicts”, explains Arthur Timmermans. Some work might also have a negative impact on certain animal and plant species, at least in the short term. “There may be impacts locally. You always have to balance the benefits and the impacts. Managing nature involves choices. There are species that benefit from the measures and others that benefit from them. suffer,” says Arnaud Laudelout.
For her part, Minister Tellier talks regarding conflicts of use. “It’s completely normal. Naturalists, farmers and public managers do not always have the same opinion, but they must succeed in transcending their differences to find common solutions. Hence the importance of having a framework” , she believes.
But for Arnaud Laudelout, Wallonia is paying the price for a lack of ambition that has lasted too long. “Conflicts with farmers and landowners illustrate a lack of effective nature conservation policies in valley bottoms. These are environments very rich in biodiversity but they have been too little targeted by the creation of protected areas. There are always conflicts and it is legitimate because some work is done at the expense of individuals. Finally, we pay for a lack of ambition that has lasted for decades.”
”It’s amazing, it’s like being in Montana!”
Giving waterways a more natural shape: a concept that does not appeal to everyone.
Eau Blanche, a tributary of the Viroin, is regarding to undergo major work aimed at giving it the most natural shape possible. The river re-meandering project, led by the Natagora association and involving a range of players (naturalists, nature reserve and natural park curators, administration, farmers and local residents) has received the approval of the Walloon Region as part of of a call for projects launched in 2022.
The construction site should start in 2024 and be completed by 2026. It should reduce the risk of flooding near the river and make the river more resistant to droughts while improving local biodiversity. “We hope in particular that the environments will become more favorable to the reproduction of fish and that the natural environments which will be recreated by naturalizing the river will be able to accommodate nests of kingfishers and plovers, a kind of small wader”, rejoices Alain Bouchat, volunteer curator of the Couvin nature reserve.
The Eau Blanche near Mariembourg is regularly polluted by hydrocarbons. ©ÉdA – 50673783233
The biodiversity of the Eau Blanche plain is already very rich: one hundred species of birds nest within the perimeter. This is almost a record in Belgium. However, some species whose natural habitat is along rivers have not been present there for a long time. This is the case for the bank swallow, the white stork and the osprey, which the curator hopes to see return following the renaturalization of the river. But if the naturalists are convinced of the benefits of the project, the same cannot be said of all the local residents who might see their land impacted by the work.
“The restoration of rivers is incredible. With a few adjustments, you might imagine yourself in Montana! But these changes are not without consequences for local residents and generate their share of conflicts. I am convinced of the benefits of renaturalization. But when I try to talk regarding the benefits around me, it doesn’t necessarily arouse great enthusiasm. You have to be honest, not everyone necessarily understands the interest of restoring waterways and some do not hesitate to show their opposition to the project”, breathes Thomas (assumed first name), a resident of the ‘White Water.
“Remeandering causes various problems in terms of land use. Many landowners are close to nature but if part of their land is to disappear in favor of the river or the Walloon Region, they are directly less delighted. In the long term, these issues will have to be taken into account by discussing well with all the people involved to explain to them the interest of renaturalization but also to inform them objectively regarding the consequences of erosion”.
“Land control is essential in order to be able to act,” agrees Walloon Environment Minister Céline Tellier. By working in the form of calls for projects, it makes things easier because the municipalities choose places where they have land control or a partnership with other owners. But we also worked on the legal framework to be able to intervene in a form of public utility easement for certain developments intended to reduce the risk of flooding. The goal is to ensure that the owner remains the owner but that the public manager can intervene”, she specifies.
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