In Lyon, despite the drought “the Rhône will be navigable for at least 20 to 30 years”
In Lyon, is the navigability of the Rhône threatened by the drought that is affecting the territory? Despite the evaporation of water, it would seem that the boatmen have nothing to fear. For the moment.
In the East of France, more precisely in the Grand-Est and in Bourgogne-Franche-Comté, the lack of water complicates the movement of boats. This drought is pushing the Voies navigables de France (VNF) to take first navigation restrictions mid-July. Traffic has been modified on the southern branch of the Rhône-Rhine canal. It is mainly commercial transport barges that are concerned, but also some pleasure boats.
What do we do when there is no more water?
When the draft is too shallow on a waterway, there are several strategies to keep navigating. One of them consists of grouping together boats at fixed times to make them cross a lock at the same time in order to limit the quantities of water released. Another vice to lighten the authorized weight on the boats to prevent them from “becoming aground”. The last solution is quite simply based on closing to navigation the least water-supplied canals. Today it is the case of 521 kilometers of waterways in France.
Lyon enhances its Geneva – Marseille motorway via the Rhône
This is an important issue when, for several years, the Voies Navigables de France (VNF) as well as the CNR (Compagnie Nationale du Rhône) have been designating the hoop as the ideal solution to fight against global warming and traffic jams in Lyon. River transport which, moreover, lags behind compared to that of the Marne or the Rhine, for example.
Last June, Cécileavezard, president of the Medlink Ports association and Rhône and Saône territorial director of the VNFs, confided to Rue89Lyon her optimism about the future of river transport in Lyon, in particular through the establishment of the Low Issuance, as well as the start of work on the Grand Port Maritime de Marseille (GPMM). The combination of the two makes river transport much more attractive for shipowners.
In Lyon, “we do not anticipate any drought problem on the Rhône”
But what if the Rhône is unable to transport goods all year round? For Pierre Meffre, director of port development at CNR, this concern is not on the agenda:
“We don’t anticipate any drought problems on the Rhône, we manage to maintain the draft. The Rhône is a powerful river. Even when we have severe low water [baisse périodique des eaux ndlr], we are able to keep from the bottom. »
Despite the spacing of rainy days and the sustained rise in temperatures in the summer period, he says there is nothing to worry about in the near future:
“Today, we have no indication that can worry us. The Rhône will be navigable without warning, at least for 20 to 30 years. Admittedly, we will have longer flood periods in the future, events will be less temperate, but that’s all. »
Over the past three years, the only natural events that have disrupted navigation have been the floods of the Saône.
“It is the Rhône glaciers that provide the river’s water resource”
Serge Barrère, CNR’s sustainable development delegate adds:
“To date, navigation is going well on the Rhône, it is a powerful, steep watercourse and it has another particularity: the succession of developments between Lyon and the sea guarantees a controlled anchorage of three meters. »
Serge Barrère compares the Rhône to the Rhine, emphasizing the “power” of the river, much less dependent on rainfall than many other rivers in France:
“It is the Rhône glaciers that provide the majority of the river’s water resources. »
These same glaciers are being hit hard by climate change. So much so that it is estimated that they will have lost more than two floors their current volume by 2100. Martin Beniston is director of the Institute for Environmental Sciences (ISE) at the University of Geneva, Switzerland. In a article for the site Encyclopédie de l’environnement, he writes that for him, the outcome is inevitable:
“By the end of the 21st century, flows are expected to be strongly activated by these changes, with an increase in winter flows linked to an early melting of the snowpack and increased precipitation, but a reduction in flows during the rest of the year. »
In Lyon: “More and more water-intensive uses are prohibited on the Rhône”
It therefore addresses the urgency of rethinking the use of the Rhône by humans:
“The seasonal changes imposed by a warmer climate will require a transformation of the current governance of water, in order to allow an equitable sharing for the economic sectors concerned. »
With regard to the Rhône, it should not be forgotten that the water from the river is withdrawn for the needs of agriculture, industries, or for cooling nuclear power stations, for example. Pierre Meffre ensures that the navigability of the Rhône will not be the adjustment variable for these industries:
“It is within a “basin committee” that the studies of arbitration are reflected, he recalls. More and more water-intensive uses are beginning to be prohibited. We project ourselves at the end of this century, with the melting of the glaciers, and we are aware that it is up to us collectively to work on this priority in the future. »