Restoration of river continuity and the upper Boivre River over 13 km.
The Boivre is a small French river in the Loire basin. Its main course and tributaries stretch for approximately 71 km. This body of water is classified as List 1 – a migratory watercourse and biological reservoir – according to Article L-432-6 of the Environmental Code.
The area concerned by the project is located at the head of the basin of the permanent flow zone of this body of water, approximately 35 km from the confluence with the Clain. It presents significant challenges for the conservation of heritage species – some of which are protected, such as brown trout, sculpin, brook lamprey, and thick shelled river mussel. These species depend on the Boivre being in good condition (free flow) and on water quality.
| Project status | Live |
|---|---|
| Project type | Dam removal: demolition |
| Country | France |
| River | Boivre |
| Removal date | 2026-2027 |
| Km to be opened | 13.5 km |
| Focal species | Unio crassus (thick river mussel), Salmo trutta (brown trout), Cottus gobio (sculpin) |
| Organisation | Syndicat du Clain Aval & ERN |
| Website | clain-aval.fr & ern.org |
The Syndicat du Clain Aval is carrying out a multi-year action programme to restore and preserve riparian vegetation and wetlands, river morphology, and ecological continuity.
In this part of the Boivre, aquatic species that require high water quality find conditions favourable to population growth. However, old weirs and mill sluices, relics of past economic activity, have caused habitat degradation along long stretches, leading to a loss of biodiversity. Many of these structures are no longer used and are in poor condition. Discussions with their owners have been ongoing for years, leading to projects for barrier removal.
The removal of seven structures will restore full ecological continuity along 13.5 km of the Boivre (removing a cumulative drop height of 4.4 m).
The project will also restore river morphology and aquatic habitats, which will create a wider variety of habitats for species that thrive in fast-flowing waters and help strengthen wildlife populations near the river’s source. Opening up this section will also allow species, particularly Unio crassus, to recolonise areas where they are currently absent.
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