The West Brabant Water Line is a defence-line consisting of a series of fortresses and cities with inundation areas in the south-west of the Netherlands. It dates from the 17th century but fell into disrepair in the 19th century. When the water line was finally restored, an access bridge across the the moat of one of the fortresses, Fort de Roovere, was needed. This fort now has a new, recreational function and lies on several routes for cycling and hiking. It is, of course, highly improper to build bridges across the moats of defence works, especially on the side of the fortress the enemy was expected to appear on.

That's why we designed an invisible bridge. Its construction is entirely made of wood, waterproofed with EPDM foil. The bridge lies like a trench in the fortress and the moat, shaped to blend in with the outlines of the landscape. The bridge can't be seen from a distance because the ground and the water come all the way up to its edge. When you get closer, the fortress opens up to you through a narrow trench. You can then walk up to its gates like Moses on the water.

The Moses Bridge was recognized as the 2011 Build of the Year by BNA, the Union of Dutch Architects.

The scenario: The West Brabant Water Works is a 17th century Dutch defensive line of earthen forts and walls that linked and protected a number of cities and villages during attacks from French and Spanish forces; inundation zones around the forts were flooded with water that was sufficiently deep to halt enemy advance on foot, but shallow enough to rule out the use of boats. As part of a recent restoration project, RO&AD architects sought to build in visitor access to the line’s Fort de Roovere, the largest fortress surrounded by a moat, while still preserving the site’s aesthetic integrity and dramatic view.

The solution: The architecture team opted for a “sunken” bridge that sits within the sight lines of the water and slope. The pedestrian walkway follows the line of the fort slope and sits almost flush with the soil and the water level. Appropriately nicknamed “Moses Bridge” for the way it parts the water, the structure is practically invisible as visitors approach and boasts a trenchlike aesthetic inspired by the location’s rich past.

Crafted with Accoya® sheet piling on either side to provide a dry walk way for visitors on the hardwood walkway and steps, the Moses Bridge maintains natural beauty suitable for the historic site while still offering the durability required for an in water and ground contact installation.

The result: The Moses Bridge is a striking example of how visually stunning design and highly functional material can go handin-hand. Accoya® wood was the ideal option to carry out the architects’ vision with properties that help to not only maintain the elegant appearance the designers were seeking but also providing a durable option that will stand up to the constant wet conditions as well as the winter freeze.