You might be inclined to think that working in a nature reserve is something that only nature managers and forest rangers do. But at BAM, we also work in nature areas every now and then. A good example of this is the Groene Woud (Green Forest) in the province of Noord-Brabant, where BAM Infra worked on the Natuurbrug De Mortelen ecoduct.
From fragmented to connected
On Tuesday 22 February of this year, the construction of this ecoduct was begun. Executive Delegate for the Province of Noord-Brabant, Johan van den Hout, Jan Baan, the director of the Brabants Landschap foundation, Communications Manager Inés Plasmans (ProRail), and Municipal Councillors Frans van Hoof (municipality of Oirschot), Mark Timmermans (municipality of Best) and Peter van de Wiel (municipality of Boxtel) together unveiled the building sign stating, in Dutch: ‘Now still fragmented. Soon to be connected nature reserves.’
The Groene Woud is a unique sequence of interconnected nature reserves: Kampina, de Mortelen, de Scheeken and the Dommel river valley. The railway connection between Eindhoven and Boxtel goes right through this area. ProRail commissioned BAM Infra to construct the Natuurbrug De Mortelen ecoduct in order to enable animals to safely go from one nature reserve to the next. Red deer are expected to be the main users of the ecoduct. Some 12 to 15 red deer were released into the area last year and the ecoduct will expand their living area.
But other animals, such as badgers, roe deer, crested newts, blindworms, lizards and tree frogs will also use the new ecoduct. Hans Vroegop, planning engineer at BAM Infra told us about this project: 'When we arrive here early in the morning, we can see roe deer, badgers and red deer. That's beautiful. And in the daytime, we're often visited by buzzards that land on the fence and come and see what we're doing.’
Protecting the flora and fauna
'Of course, we take the protected flora and fauna into account during our work,’ said Hans. ‘Every two weeks, ecologists study the area for any species of animal that may need to be relocated. They started relocating the crested newts, lizards and tree frogs last year in order to prepare the site for building. Once the animals had been taken to safety, special screens were put up around the area to keep animals out.’
‘We also make use of sustainable materials, and materials that originate from the actual nature reserve as much as possible. For example, bioblocks will be used to finish the actual ecoduct. These are blocks with compacted cut reed. We're using as little concrete as possible. We have other solutions instead, such as a reinforced soil structure that consists of layers of soil and geotextile. In the end, the ecoduct should be entirely covered in moss and different species of grass to have it blend in with nature.’
‘I'm a technical guy, but for this project I often meet with ecologists,’ Hans said. ‘One of the subjects we discuss is creating ecological ponds. That's a completely different business, but I really enjoy it. We talk about things like creating a beach for newts, where they can enjoy the sun. The beach must have exactly the right slope; it can't be too steep because then they'd slide down it. And the pond shouldn’t be too deep, because then there will be fish in it that eat the eggs of the protected frogs.’
Road through the woods
‘Another challenge is how to access the building site. A one-kilometre long road through the woods was created especially for this project. But taking all the equipment and raw materials to their destination is quite a complex puzzle. This must be phased very carefully in order not to pose a too high burden on the nature. It has been planned that all animals should be able to cross by early 2019.