Pont de Rhodes Weir, France

Removing the weir at Pont de Rhodes Mill on the Ressègue Stream to restore ecological continuity and improve the habitability of the area.

Introduction

The weir at Pont de Rhodes mill is situated on the Ressègue, a tributary of the Escalmels stream, which in turn feeds into the Cère River. This location falls within the Natura 2000 special conservation area FR8302033: ‘Affluents de la Cère en Chataigneraie’, notable for its substantial population of pearl mussels and recent evidence of their reproduction. The area is affected by agricultural activities, particularly livestock farming, impacting the water and environmental quality. Several dams and weirs, remnants of former mills like the one at Pont de Rhodes, present significant local challenges.

At a glance

Project typeDam removal: demolition
Project statusLive
Demolition dateAutumn 2024
CountryFrance
RiverLa Ressègue
Km to be opened13
Focal speciesFreshwater pearl mussel, brown trout
Websitehttps://www.ern.org/en/openrivers/

Project context and opportunity

The Ressègue River falls under List 2 of Article L214-17 of the French Environment Code, requiring owners of such structures to adhere to ecological continuity regulations. Given its importance for the reproduction and habitat of pearl mussels, removing the structure on this river is deemed a priority by the expert unit of the Auvergne-Rhône-Alpes National Pearl Mussel Action Plan. This action would yield significant ecological benefits for the river and potentially connect two pearl mussel populations. The Open Rivers programme has provided financial support to enable owners to pursue this solution and ensure compliance with French legislation.

Project aims

The project aims to restore the ecological and hydromorphological continuity of the Ressègue river while enhancing the population of pearl mussels and maintaining the fario trout population, crucial for mussel reproduction. Precision in relocating mussel individuals, alongside weir removal and habitat diversification, will be key in achieving these goals.

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