Case study:Restoration of the river continuity on the Touques Basin

From RESTORE
Jump to: navigation, search
0.00
(0 votes)


To discuss or comment on this case study, please use the discussion page.


Location: 49° 20' 36", 0° 6' 5"
Edit location
Loading map...
Left click to look around in the map, and use the wheel of your mouse to zoom in and out.


Project overview

Edit project overview
Status In progress
Project web site
Themes Flood risk management, Habitat and biodiversity, Hydromorphology
Country France
Main contact forename Yannick
Main contact surname Salaville
Main contact user ID
Contact organisation Fédération de pêche du Calvados
Contact organisation web site http://www.federation-peche14.fr/
Partner organisations Direction départementale de l’agriculture et de la forêt (DDT), conseil supérieur de la pêche (now National Agency for Water and Aquatic Environments - Onema)
Parent multi-site project
This is a parent project
encompassing the following
projects
No
Restoration of free movement of migratory fish in the basin of the Touques between 1980 and 2009 (Arnaud Richard, Onema)

Project summary

Edit project overview to modify the project summary.


Several actions are performed to restore river continuity. Obstacles (weirs, sluices, dams) are opened, removed or fitted with fish passes.

Before the first fishway on the Calonne in 1982, some fifteen or so obstacles in the Touques basin had already been dismantled or opened to facilitate flood evacuation. Almost 30 years on, 71 other obstacles have been redeveloped, i.e.:

• 33 weirs removed, lowered or opened including the removal of the Lisieux flap gate dam (implementation: 2007, project owner: commune of Lisieux - see the corresponding example from the collection).

• 38 weirs equipped with fish passes including a multi-species fishway on the Breuil-en-Auge dam (implementation: 1999, project owner: Fishing federation of Calvados) and the development of 4 fish passes on the Cirieux (implementation: 2008, project owner: commune of Saint-Désir)

As progress has been made, grants received by project owners have supported this programme: The Ministry of the Environment, Conseil supérieur de la pêche (CSP - now Onema), the départements of Calvados, Orne and Eure, the fishing federations of Calvados and Orne, European funds. Currently: the Seine-Normandie and the Region of Basse-Normandie water agency

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.


Counting of sea trout travelling upstream at Breuilen-Auge has been carried out since 2001. This monitoring is implemented under an agreement with the owner of the dam and of the fishway.

Reproduction areas accessible to sea trout have increased sharply, thanks to improvements works carried out over the past 30 years. The proportion of accessible surfaces thus increased from 15% before 1982 to 86% in 2009. The sea trout travelling upstream monitored at the Breuil-en-Auge fishway represented 2,500 fish in 2001 and more than 6,000 in 2008, a figure confirmed in 2009 with over 5,500 sea trout. As the monitoring station was located upstream to many tributaries, the current Touques stock is therefore now 10,000 sea trout, making it not only the number one river in France for sea trout but also one of the best in all of Europe. These very good results are accompanied by a significant rise in fishing tourism.

The scale of these actions and their results make the Touques basin a benchmark for continuity in the Seine-Normandie basin.

The Touques axis is completely open to migration, but there are still a dozen or so more obstacles upstream of the tributaries. There are several projects under way. The most penalizing obstacle lies in the middle part of the Calonne. This obstacle, devoid of fish passes despite the regulatory obligations, neutralises the efforts already made upstream in the Eure département due both to the obstruction of upstream fish migration but also damage caused by the turbine on fish returning to the sea.

Lessons learnt

This case study hasn’t got any lessons learnt, you can add some by editing the project overview.


Image gallery


Orville dam on the upper Touques before and after its removal (Arnaud Richard, Onema).
Breuil-en-Auge fishway (Arnaud Richard, Onema).
ShowHideAdditionalImage.png


Catchment and subcatchment



Site

Name
WFD water body codes FRHR275 and FRHR277 FRHR276, FRHR279, FRHR278
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 10 - 50 m
Average bankfull channel width (m) 15
15 m
0.015 km
1,500 cm
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category 1 - 10 m³/s
Mean annual discharge (m3/s) 9
9 m³/s
9,000 l/s
Average channel gradient category 0.001 - 0.01
Average channel gradient 0.003
Average unit stream power (W/m2) 17.6526
17.653 W/m²


Project background

Reach length directly affected (m)
Project started
Works started
Works completed
Project completed
Total cost category 1000 - 5000 k€
Total cost (k€) 3700
3,700 k€
3,700,000 €
Benefit to cost ratio
Funding sources Ministry of the Environment, Conseil supérieur de la pêche (CSP - now Onema), the départements of Calvados, Orne and Eure, the fishing federations of Calvados and Orne, European funds, Seine-Normandie, Region of Basse-Normandie water agency

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
Post-project management and maintenance
Monitoring



Reasons for river restoration

Mitigation of a pressure Flood risk management
Hydromorphology Continuity of sediment transport, Continuity for organisms, Freshwater flow regime
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications removal of sluices, removal of dams, Creation of fish passes, Weir removal, Weir lowering
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

Biological quality elements

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

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


Monitoring documents



Additional documents and videos


Additional links and references

Link Description
http://www.onema.fr/sites/default/files/EN/EV/publication/rex TouquesGB.pdf All information on this page is copied from the AFB, the French organisation for biodiversity.

Supplementary Information

Edit Supplementary Information