17/06/2025

Reading time: 4min

Sweco Belgium

New Waaltjesbos Ecoduct Connects Nature Reserves in Limburg

In Lommel, the brand-new Waaltjesbos ecoduct in the Bosland National Park has been officially opened in the presence of Flemish Minister Jo Brouns. The ecoduct spans the N71 and forms a crucial link between the Kristalpark and the Waaltjesbos. This creates an ecological corridor connecting the Pijnven-Kattenbos and Sahara-Blekerheide nature areas.

Defragmentation through Joint Efforts

This project is an initiative of the Flemish government and is part of the Flemish Action Programme for Ecological Defragmentation (VAPEO), which aims to restore connections between fragmented natural areas. The ecoduct was realised under the leadership of De Werkvennootschap, with support from the Agency for Nature and Forests (ANB), the Department of Environment, and the Agency for Roads and Traffic (AWV). The design and construction were carried out by the team of Jan De Nul and Sweco. Their experts in civil engineering, landscape, and ecology are giving a boost to the habitat for flora and fauna in Limburg.

Nieuw ecoduct Waaltjesbos verbindt natuurgebieden in Limburg

Nieuw ecoduct Waaltjesbos verbindt natuurgebieden in Limburg

Prototype with Smart and Natural Design

This ecoduct is a simple yet effective model that can serve as a prototype for future projects. It is a repeatable design that can be applied elsewhere in Flanders.

The ecoduct consists of a wide concrete slab spanning the N71, supported by a transparent cylindrical column structure. Earthen embankments on the sides help the structure blend visually into the landscape. The retaining walls are finished with gabions. The ends of the concrete slab are tapered to make the ecoduct appear lighter, and a simple wooden railing ensures safety and screening.

On the ecoduct itself, various natural zones have been created: an open, dry area in the centre and more shrubby zones along the edges. Along its entire length, deadwood walls—recovered from the Waaltjesbos—provide additional shelter for animals.

A Blessing for Biodiversity

Until now, the N71 was a barrier for many animal species. Thanks to the ecoduct, animals can now safely move between the surrounding nature reserves. The design takes into account various habitats: wet zones, dry zones, and transitional areas ensure that a wide range of species—from amphibians to small mammals—can use the crossing.

The nearby Waaltjesbos is also a valuable nature reserve within Bosland, home to rare species such as the smooth snake and the spring hunting spider.

Nieuw ecoduct Waaltjesbos verbindt natuurgebieden in Limburg
Nieuw ecoduct Waaltjesbos verbindt natuurgebieden in Limburg
Nieuw ecoduct Waaltjesbos verbindt natuurgebieden in Limburg

Flanders Continues to Build Nature Connections

The opening of the Waaltjesbos ecoduct is not a standalone project. The same team is also working on the ecopassage under the N76 in Zwartberg, while Willemen/Franki Construct is realising a Sweco design for the Dilserbos ecoduct over the N75. Both connections are expected to be completed by summer 2025.

With these initiatives, Flanders continues to take steps in restoring ecological connections. In a region where fragmentation of natural areas is a challenge, projects like this ecoduct contribute to better cohesion between valuable nature reserves. Such infrastructure projects support biodiversity conservation and strengthen habitats for many animal and plant species.

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