Renovation of the Liégeot weir
The weir at Liégeot was built in 1958 and has got the special feature of being composed of three weir fields of 34 m equipped with fixed-wheel type closures.
Right from when they were commissioned, these closures posed difficulties in terms of functioning as well as maintenance.
Sealing problems developed rapidly (as early as 1965), thus creating significant vibrations in the gate structures.
The very concept of fixed-wheel gates hampers not only maintenance of certain components but also treatment against corrosion. This holds especially true for the ends of the gates which are particularly exposed and vulnerable.
In light of these issues, Direction Territoriale Nord-Est commissioned several studies and diagnostics which confirmed the overall dire state of the structure’s moving parts and recommended urgent measures to protect or reconstruct the structure.
The risks of breach had been touched up elsewhere in these various reports. Such an eventuality would have had disastrous consequences for the waterway and thus for VNF.
A study of the Moselle’s route, carried out as a part of the action programme on the reliability and safety of the infrastructure, took into account the critical point that the weir at Liégeot represents.
In parallel to these studies and diagnostic reports, various conservation measures and a monitoring plan were introduced.
Ultimately the civil engineering of low-quality, prefabricated cabins was unable to withstand the ravages of time, lending the structure a dilapidated look and offering but weak protection for the moving parts against adverse weather conditions.
The Liégeot weir stands on the one hand for the high economic stakes for ports and factories both upstream and downstream (development of the Frouard port to Rhine-gauge size locks and the development of the Neuves-Maisons port, maintaining water levels for power generation, the St. Gobain factory, etc.), and on the other hand for spatial planning within the project to link the Saône and the Moselle with the aim of building an interconnected European inland waterway network.
Photographs of the Liégeot weir, its geographical location and an aerial shot of the weir and its small hydro-electric power plant:
Further information on the work carried out on the Liégeot weir.
Source: Direction Territoriale Nord-Est de VNF
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