Hastière is a town located an hour and a half’s drive south of Brussels. It is best known for its Saint-Pierre Abbey, a masterpiece of Romanesque architecture. This famous building stands directly on the banks of the Meuse, demonstrating that the river has been a major transport route for centuries. Consequently, the fledgling nation of Belgium, which gained its independence in 1830, quickly embarked on major works to develop the river into a modern transport route. Indeed, its banks are dotted with numerous stone quarries and forests, the materials from which are essential to the country’s economic functioning. This would also facilitate trade with neighbouring countries (the Netherlands to the north and France to the south).
River navigation was completely modernised in the 19th century. From the French to the Dutch border, 15 weirs are managed by lock-keeping stations to maintain the water level up to the next weir. However, the river remains turbulent and experiences annual floods carrying dead wood. To prevent damage or being swept away, the weirs must be completely dismantled during every major flood and then quickly reassembled. Engineers developed two types of movable weir to meet these requirements. Nine of the fifteen weirs use both types simultaneously and are known as 'mixed weirs'. Two small sections of these two types are now preserved near the Hastière lock.
The first type is the 'needle dam', which was designed by the French engineer Antoine Poirée in 1834. It consists of long wooden poles supported by a metal framework. If a floating object is present, the poles can be removed one by one to allow it to pass through, before being put back in place. In the event of a flood, the poles are removed and the metal framework is laid flat on the riverbed, perpendicular to the direction of the current.
The second type is the 'wicket dam', which was invented around 1850 by the French engineer Jacques Henri Chanoine. It consists of a series of planks held upright by a metal support. Each plank has an opening, known as a 'wicket', that allows some water to pass through while keeping the rest of the structure intact. Depending on the flow rate, this type of dam can be operated in four ways: with the plank raised; with the plank raised and the sluice gate open; with the plank positioned at an angle to allow water to pass over and under; or with the plank laid flat on the riverbed . The metal structure that provides support for each panel can be laid flat on the riverbed in the event of flooding, similar to the needle dam but in the direction of the current.
Although these two types of weir were highly ingenious, they have now completely disappeared from the Meuse in Belgium. They have been replaced by large, automated, movable gates. Hastière was the last combined weir on the Meuse and remained in use until 1983. This is why the two sections of this historic weir have been preserved. This is the only place where they can still be seen together. Information panels around the site explain how the mechanism worked — it was as ingenious as it was complex. This site allows visitors to appreciate the evolution of navigation techniques on the Meuse over the centuries. It also preserves the memory of structures that have now completely disappeared from the landscape.
