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Major damage to the valve on the Moulin du Boël dam
At the end of January 2024, the Brittany Canal Authority detected major damage to the flap gate at the Moulin du Boël dam in Bruz, near Rennes. This essential piece of equipment, measuring 32 meters in length, regulates the water level of the Vilaine, making river navigation possible. However, a significant torsion of the dam was noted, preventing the flap gate from functioning properly and maintaining the water level required for navigation. According to the region, "the he damaged flap gate prevents it from being fully raised and the water level from being maintained for navigation ".
Navigation suspended between Saint-Malo and Arzal
With the dam submerged, initial repair attempts proved unsuccessful. In order to prevent any risk of further damage, the Brittany region has decided to " set valve to safety position "This means lowering the level in the reach. The replacement work, involving the installation of two new sluice gates, is scheduled to take place from April to October 2025. During this period, and until the resumption of the navigation season in spring 2026, navigation between the Pont-Réan lock and the Boël mill will be impossible. This interruption directly affects the river link between Saint-Malo and Arzal, making the crossing impassable for all boats on this three-kilometer stretch... unless they are transported by land.
A major investment for a major project
The replacement of the Moulin du Boël dam flap gate represents an investment of 4.5 million euros. The Brittany region, which manages the waterways in its area, had planned this work, and began studies in early 2023 to prepare for the operation, which was entrusted to a design office in October 2023. However, as David Moy, Director of Brittany's canals, explains, " as soon as work is carried out in a wet environment, the cost is multiplied by a factor of two ". Pending completion of this work, the damaged flap gate must be lowered as a precautionary measure to prevent it from tearing completely, which would result in a significant drop in the water level on the section concerned, making navigation impossible.
A worrying situation for boaters and yachting professionals
The situation is a source of concern for boaters and yachting professionals who use this waterway. The decision to suspend navigation until 2026 is a major blow to the dynamics of river tourism in Brittany, which had been booming in recent years. Prospects for a resumption in 2026 should enable river activities to be relaunched under better conditions, reinforcing the attractiveness of this Channel-Ocean link for years to come.
With the atlantic-Mediterranean link blocked as bridge on Canal Latéral à la Garonne threatens to collapse the summer of 2024 is definitely not a time to celebrate for boaters who want to take to the sea via the waterways.
