This 107-kilometer-long, 54-meter-wide canal aims to increase river traffic in the Hauts-de-France region, with the stated goal of reducing the climate change impact of freight transport. However, some researchers are concerned about false promises, as the construction, launched in 2022 after more than a decade of preparations, is in full swing in Montmacq, in the Oise department, where machinery is actively working to build a lock. 

After a long period of relative quiet, the mobilization of anti-canal activists has materialized in recent weeks through sporadic tree occupations and an unprecedented protest that gathered over a thousand people in mid-October near the construction site. 

The main argument in favor of the canal is "modal shift from road to a cleaner mode of transport," summarizes Pierre-Yves Biet, an executive at the Seine-North Europe Canal Company (SCSNE), the public entity overseeing the project. But this argument is based on theoretical estimates, which "must be approached with great caution," says Frédéric Huet, a lecturer in economics at the University of Technology of Compiègne (UTC). 

Notably because river transport "is not a terminal mode of transport": "road transport is always needed" to deliver goods to their final destination, reminds Emilie Lorant-Plantier, a geography professor and author of a thesis on this canal. 

"Moratorium"

A group of UTC researchers, including Mr. Huet, called for a "moratorium" on the project in an op-ed, suggesting instead to rethink rail transport and renovate the existing river network. Stéphane Crozat, a member of the group, summarizes: "It's more of a 20th-century, or even 19th-century project," while it is intended to be used until the "22nd century." Without a strategy to slow the growth of transport, "there will always be more trucks," he emphasizes. 

The canal is "a lever, though probably not the only one, to enable companies to transport more cleanly," counters Pierre-Yves Biet. For him, it should not be "opposed" to rail transport but is part of a "multimodal" logic. 

The challenge will remain to convince these companies to invest in the canal, particularly by "ensuring that regional stakeholders who are not located near the waterway can come to use it," notes Laurent Degroote, president of the Economic, Social and Environmental Council (Ceser) of Hauts-de-France and co-author of a report on the canal. 

"It won't happen overnight," but for him, the project is an "opportunity" that the region "cannot afford to miss." 

Artificialization

Agnès Ducharne, a hydrologist at CNRS, is concerned about the risks to water resources, as the canal's water supply relies on the Oise River. 

"Climate change tends to reduce river flows in summer in France, including in the north, so it will become increasingly difficult to draw from the Oise in summer," she points out. 

She shares the view that the canal is the result of "a vision of France's socio-economic functioning from a bygone era, while we should be preparing for the transition," and laments that it requires "the artificialization of thousands of hectares." 

Mr. Biet acknowledges that it will cause "destruction" of ecosystems, but "as with any large-scale project in France," measures are being implemented to "reduce" and "compensate" for biodiversity loss. Amphibians and fish have been relocated, and trees and herbaceous plants have been planted. 

Some scientists remain skeptical about the effectiveness of these measures: "Experience shows that there is always a net loss of biodiversity, even after compensation," notes Gabrielle Bouleau, a political science researcher at INRAE and co-author of a study report on the canal. 

Its cost also raises concerns during times of budgetary uncertainty. Initially estimated at 5 billion euros, funded by the state, local authorities, and European funds, it is expected to be significantly revised upwards. 

In a report published at the end of 2024, Ceser estimated that "the final cost of the project could range between 7 and 8 billion euros," mainly due to the cost of materials. 

By Claire Line-Nass