Case study:Partial removal of a weir on La Corrèze river in the town of Tulle

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Location: 45° 16' 30", 1° 46' 24"
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Project overview

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Status Complete
Project web site
Themes Fisheries, Habitat and biodiversity, Social benefits
Country France
Main contact forename Anne
Main contact surname Chollet
Main contact user ID
Contact organisation Communauté de communes Tulle et Cœur de Corrèze
Contact organisation web site
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No
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Project summary

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On the river Corrèze, near the town of Tulle, five weirs interrupted the ecological continuity and limited the recreational use of the river, since the passage of kayaks was hindered. The largest, 3 m high, was identified as the most problematic. This weir was partially removed (levelled), maintaining its basement and a residual 30 cm drop, to ensure the stability of the longitudinal profile, but at the same time allowing the passage of fish and canoes. Downstream of the weir, a 40 m long riprap ramp was realized, to avoid erosion. The ramp was built with a curved shape to concentrate flows and facilitate the passage of fish fauna at low water level conditions. Along 600 m upstream the weir and on the internal side of the meander, the banks were protected with the installation of a vegetated geotextile. On the external side of the meander blockstone deflecting groynes were positioned, alternated with layers of coarse gravel extracted from the riverbed, in order to protect the retaining wall of the existing road. Monitoring of hydromorphology, vegetation and fish fauna has been foreseen.

Monitoring surveys and results

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Lessons learnt

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Image gallery


The Tulle weir in June 2008, before the leveling works
The Tulle weir in September 2008, after the leveling works
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Catchment and subcatchment

Catchment

River basin district Adour Garonne
River basin Adour - Garonne

Subcatchment

River name Corrèze
Area category
Area (km2)
Maximum altitude category
Maximum altitude (m)
Dominant geology
Ecoregion Western Plains
Dominant land cover
Waterbody ID



Site

Name Tulle
WFD water body codes FRFR324A
WFD (national) typology
WFD water body name
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body No
National/international site designation
Local/regional site designations
Protected species present No
Invasive species present No
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category
Mean annual discharge (m3/s)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m) 600
600 m
0.6 km
60,000 cm
Project started
Works started 2008/06/01
Works completed 2009/09/01
Project completed
Total cost category
Total cost (k€) 293
293 k€
293,000 €
Benefit to cost ratio
Funding sources Agence de l’eau (30 %), FEDER (26 %), communauté de communes Tulle et Coeur de Corrèze (20 %), conseil régional (14 %), conseil général (10 %).

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design
Stakeholder engagement and communication
Works and works supervision 293
293 k€
293,000 €
Post-project management and maintenance
Monitoring



Reasons for river restoration

Mitigation of a pressure Barriers to fish migration
Hydromorphology Continuity for organisms
Biology Fish
Physico-chemical
Other reasons for the project canoes kayaks movement


Measures

Structural measures
Bank/bed modifications Bed reprofiling, Weir modification
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Substrate conditions Yes Yes No No No
Flow velocities Yes Yes No No No
Quantity & dynamics of flow Yes Yes No No No

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Fish No Yes No No No

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
river bank vegetation Yes Yes No No No


Monitoring documents



Additional documents and videos


Additional links and references

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Supplementary Information

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