/medias/ZXr66LkaBv/image/Photo_Seuil_en_Maine1724656848481.jpg?fit=%2C&ssl=1)
105 metres long, this threshold includes four flaps, each measuring more than 25 metres.
Credit: Pierre-Louis Besnier
After the statue of King René a few weeks ago, it is the turn of the flaps of Seuil en Maine to be taken down. Built between September 1992 and June 1994, The Threshold in Maine aims to maintain the water level of Maine when the Loire is low. Measuring 105 metres in length, it comprises four flaps, each measuring just over 25 metres and weighing 15 tonnes. The whole is made up of a lock, a fish pass and a movable dam on the Maine. Last Thursday, it was lifted and taken away for renovation. The Department of Maine-et-Loire manages this equipment.
Check the condition of each valve
The objective of this operation is the following, or rather the following: successively check the condition of each valve and to carry out maintenance work if necessary: “The point is to make sure that there is a overall maintenance of all valves and to be able to get them out of the water, so that the company Vercheanresponsible for the mission, can process them directly on a dedicated site”explains the vice-president of ecological transition within the Maine-et-Loire Department, Marie-Jo Hamard.
However, the intervention was supposed to take place a few months ago: “The intervention had to take place in October but it had to be delayed to this day since we had had water levels too high. And the company was therefore not able to lift these valves”continues Marie-Jo Hamard.
Credit: Pierre-Louis Besnier
The importance of biodiversity
This lowering may result in several economic and ecological disturbances on the river which crosses Angers, but also on the Mayenne and Sarthe basins. For example, it can cause difficulties in crossing locks. Cheffes-sur-Sarthe or Montreuil-Juigné. “What is important is at the level of biodiversity and ecology. The idea is to ensure that wetlands are favoured to maintain this fauna and flora which is essential to the balance of our environment in a global way”, says the vice-president of ecological transition within the Department of Maine-et-Loire before adding that “It’s really a technique, or in any case a particular monitoring of this Maine Threshold which has a much broader impact than we think on all the other rivers that flow into Maine“.
It should also be noted that the absence of water in drinking holes or on the banks is a disruptive element for wildlifeespecially for spawning grounds at Pike.
Credit: Pierre-Louis Besnier
La Verchéenne company in charge of the operation
The first valve was taken out of the water last Thursday and was cleaned with a view to a thorough inspection of the structure, welds and paint. It was then sent to a specialist company in Verchers-sur-Layon for the purpose of sandblasting. The company The Verchéenne volunteered to do the work. “We are working with a local company that responded to a call for tenders and it was chosen. We have entrusted it with a certain number of works since The Department manages 250 kilometers of river. On the river in general and in particular, there are maintenance works which must be regular and which must be carried out by companies which are technically competent and specialized in this type of work”declares Marie-Jo Hamard.
Valves number 2, 3 and 4 will be subject to similar interventions. until 2026. As for the first valve, the cost of the intervention is estimated at 352 000 euros.
Credit: Pierre-Louis Besnier
