Ecological restoration of the Rhone at Pierre-Bénite

A global and ambitious programme

The ecological restoration of the sector of Irigny, Vernaison and Feyzin is part of a huge programme initiated in 1998 by local actors including CNR. It involves the sections of the river located over its entire length. Carried over to the Rhone Plan of 2006, it is also part of the European Framework Directive on Water aimed at reaching the good ecological state of aquatic habitats.

Success already proven in other territories

Ecological monitoring has shown that the Rhone’s restoration has benefited the species typical of large rivers and increased the biological diversity of the alluvial plan. Thus, 77 oxbows have been restored along 120 kilometres of the Rhone.

The goals targeted

Return the Rhone to more natural functioning with more space to evolve and with sediment transport partially restored.
Favour biodiversity, by re-establishing habitats favourable for a large number of species, including certain rare or protected ones.
Increase the positive effects of floods especially in the oxbows, thereby favouring “self-maintenance” to limit clogging by sediments, and allow erosion processes that diversify ecosystems.
Prepare the river’s resilience to climate change, by favouring exchanges between all the aquatic habitats composing it: main channel, secondary branches, wetlands, underground aquifers, etc.

The actions carried out

Remove the Girardon spur dikes.
Excavate the beds of former oxbows and new secondary branches.
Return to the river fines and coarse materials taken from earthworks, leading to the return of sediment continuity and restoring the river bed.
Plant varied and adapted species (black and white poplars, white willows, etc.) to combat colonisation by invasive species.

The works accomplished

Dismantling of rockfill spur dikes (environ 80,000 m³ removed and recycled).
Excavation of more than 5 km of secondary branches.
Treatment of floating primrose willow and rejuvenation of the Jaricot oxbow.
Excavation of groundwater pools.
Reconnection of the Ciselande oxbow to compensation water.
Removal of the water inlet from the oxbow.
Remobilisation of the alluvial bank.
Creation of a wetland over 1.1 hectare (notably an aquatic reedbed).
Connection of the Guinet pond to the Rhone linked with the creation of spawning grounds.
Creation of a spawning ground, in particular for pike.

The earthworks will require the removal of about 2,000 trees (of which 25% are invasive species), which will be mostly offset by the plantation of 5,000 trees and shrubs belonging to adapted species bearing the Local Plant label. Nearly 380,000 m³ of sediments will be moved in the framework of the project.

The calendar

The works will be carried out in 3 phases, each time between the months of September and March, to limit impacts on the biological cycles of plant and animal species as well as the use of the site for leisure purposes. Started in January 2025, they are due to end in spring 2028.

A project subject to scientific monitoring and designed in concert

For 20 years, the global project of the ecological restoration of the Rhone has been carried out in parallel with a scientific research programme, RhônEco, that above all performs ecological monitoring. Regular dialogue with CNR makes it possible to adapt actions according to feedback from the field and check the efficiency of the measures taken.

Extensive consultation was carried out with the territories, river users, (walkers, anglers, cyclists, hunters, canoeists, etc), the neighbouring population, nature associations, scientists, and institutional and financial actors such as the State, the Rhone-Mediterranean-Corsica Water Agency and the European Union. Different visits to sites and workshops organised with the SMIRIL, which brings together a user’s committee, led to the shared conception of this project of proven utility.

With the support of the following partners:

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Ecological restoration of the Rhône river – Irigny, Vernaison and Feyzin sectors Durée : 5:17