This project aims to remove a culvert on a high-quality forest stream in southern Belgium to reopen 2.4 km of ecological connectivity for migratory fish species.
The Ri du Wéry is a small, pristine forest stream located in the Lesse catchment, a tributary of the Meuse River in Wallonia, southern Belgium. Flowing entirely through a Natura 2000 site, the stream is remarkable for its ecological integrity: it receives no urban or agricultural pollution and supports key aquatic species including brown trout, grayling, bullhead, and thick-shelled river mussel.
Despite this exceptional quality, the stream’s ecological continuity is broken by two concrete culverts installed under a forest road.
| Project status | Completed |
|---|---|
| Project type | Dam removal: demolition |
| Country | Belgium |
| River | Ri du Wéry |
| Removal date | June - September 2025 |
| Km to be opened | 2.4 km |
| Focal species | Brown trout (Salmo trutta), grayling (Thymallus thymallus), bullhead (Cottus gobio), and thick-shelled river mussel (Unio crassus) |
| Organisation | Parc naturel Ardenne méridionale, Commune de Wellin |
| Website | Ardenne méridionale |
The Ri du Wéry is one of many small forest streams in Wallonia where fish passage is hindered by outdated infrastructure. Although the culvert allows forestry vehicle access, it blocks upstream migration for fish species and disrupt sediment flow.
Given the excellent ecological status of the waterbody and its location in a protected area, removing this barrier presents a rare opportunity to restore a near-natural aquatic ecosystem.
The project has brought together multiple local actors, including the Municipality of Wellin, the Department of Nature and Forests, and the Lesse River Contract, to demonstrate how small-scale barrier removal can deliver high ecological returns in forested catchments.
The project’s main goal is to restore full longitudinal connectivity over more than 2 km of the Ri du Wéry by removing one out of two concrete culverts and replacing it with fish-friendly crossings.
In 2025, the first culvert will be removed and replaced by a hydraulically transparent modular structure (precast concrete slab and mega-block abutments) that maintains forestry access while allowing uninterrupted stream flow. The second culvert is planned for removal in 2026, pending funding.
The project will improve access to spawning habitats for trout and grayling, enhance habitat quality and sediment dynamics, and serve as a replicable model for other forest streams. Ecological monitoring will be led by the Lesse River Contract.
In September 2025, the Ardenne Méridionale Nature Park and partners removed a concrete culvert on the Ri du Wéry (Wellin, Belgium), a high-quality Natura 2000 forest stream in the Lesse–Meuse basin. The crossing was replaced with a hydraulically transparent, modular open-arch underpass (mega-block abutments with a precast deck), avoiding in-situ concrete and minimizing construction impacts.
The intervention reconnected >5 km of mainstem and around 17 km when downstream tributaries are included, restoring access to upstream spawning and nursery habitats for brown trout and grayling, with added benefits for bullhead and freshwater mussels (e.g., thick-shelled river mussel). Permits are in place for a second culvert, planned for 2026 subject to co-funding, which would raise contiguous connectivity to over 7 km.
The project was co-funded by the Open Rivers Programme, the Walloon Region, and BiodiverCité (Wellin), with monitoring by the Lesse River Contract to document recolonisation, habitat recovery, and structure performance.
Funded by
