Case study:Creation of flood channels and restoration of exchanges between the flood plain and the low-flow channel on the Vezouze

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


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


Location: 48° 35' 12", 6° 29' 12"
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 Complete
Project web site http://www.onema.fr/IMG/EV/publication/rex_VezouzeGB.pdf
Themes Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Urban
Country France
Main contact forename Josee
Main contact surname Peress
Main contact user ID User:Josee Peress
Contact organisation AFB
Contact organisation web site http://www.onema.fr/Hydromorphologie,510
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No

Project summary

Edit project overview to modify the project summary.


The work consisted of widening the river’s middle water channel in some places. For this, a protective levee has been levelled on the left bank. Two flood channels, measuring one metre on average over 6 hectares, have been dug, involving the removal of 60,000 m3 of material. Within these flood channels, wetland environments such as ponds and side channels have been created. Trees have been planted on the banks as well as helophytes in flood channels. In addition to these actions on the environment, work on the rainwater system has also been undertaken: check valves and pumping stations have been set up.

The Vezouze maintenance syndicate manages the removal of blockage and debris as required.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.


A pre-restoration monitoring was carried out by a consultancy in 2000 and again in 2003, 2004 and 2005 on the hydraulic component. Investigations were required to study the hydrography, hydrology, topography and geology of the land. A bibliographic study was used to describe the biological component of the aquatic environment. Post-restoration ecological monitoring (habitats, species) began in 2010 and will continue until 2014. This monitoring consists of describing the natural environment and assessing the impacts (positive and / or negative) of operations on animal and plant life, specifically targeting the restored flood plain and side channels created. The hydromorphology and biological communities living in the lowflow channel (fish, aquatic invertebrates, etc.) are however not investigated in this work.

The first results of 2010 and 2011 highlight several outstanding species for Lorraine, including insect and plant species. It will therefore be very interesting to monitor the evolution of these species on the site. Particular attention will be paid to plants receiving protected status, as these species were most likely to have been introduced during the restoration work.

The ecological evolution of the site is very satisfactory. The results of monitoring attest to the positive effects of the work on biodiversity with the presence of wildlife characteristic of wetlands and the presence of outstanding species in terms of flora and insect life. The evolution and diversification of the side channels, which have a dense vegetation of helophyte-type plants, are also very conducive to pike reproduction (even though there is no monitoring of this aspect, side channels here show strong potential).

Hydraulically, the results are equally satisfactory. Upstream to the restored area, height and surfaces of areas flooded in Lunéville have significantly diminished.

As the primary objective of this restoration is flood defence, the explanation to elected representatives of the benefits of preserving the flood storage area and diversifying habitats in the flood plain has led to the setting up of a project that reconciles hydraulic and ecological objectives. Cross-cutting objectives particularly motivated elected representatives who were thus able to meet the expectations of the local population in terms of safety and landscaping issues. These developments make it possible to combine flood management and improvement of the ecological status of the river.

In addition, a pedestrian path has been created in the area and its regular use reflects the renewed interest of local people for the site. Previously, they tended to avoid this unattractive, unsightly sector. The work thus helped to enhance “nature” in a peri-urban area.

Lessons learnt

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


Image gallery


The Vezouze at Lunéville before restoration work. The levee on the left bank prevents flood storage in the flood plain (Rhin-Meuse Water Agency)
Flood plain of the Vezouze. Creation of a flood channel on the left bank - work phase – July 2007 (Philippe Russo - Rhin-Meuse Water Agency)
Flood plain of the Vezouze. Flood channel on the left bank - 6 months after the work - December 2007 (Philippe Russo - Rhin-Meuse Water Agency)
Flood plain of the Vezouze. Flood channel on the left bank - 2 years after the work - May 2009 (Pierre Mangeot - Rhin-Meuse Water Agency)
ShowHideAdditionalImage.png


Catchment and subcatchment



Site

Name La Vezouze
WFD water body codes FRCR286
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) 20
20 m
0.02 km
2,000 cm
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category 1 - 10 m³/s
Mean annual discharge (m3/s) 6.8
6.8 m³/s
6,800 l/s
Average channel gradient category 0.001 - 0.01
Average channel gradient 0.0015
Average unit stream power (W/m2) 5.00157
5.002 W/m²


Project background

Reach length directly affected (m) 1000
1,000 m
1 km
100,000 cm
Project started 2007/05/01
Works started
Works completed
Project completed 2007/08/31
Total cost category 1000 - 5000 k€
Total cost (k€) 1930
1,930 k€
1,930,000 €
Benefit to cost ratio
Funding sources Regional Directorate for the Environment (DIREN): 20.5%, Water agency: 34%

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 Quantity & dynamics of flow, Continuity for organisms
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications Construction of flood channels, Removal of material, Pond creation, Side channel creation, setting up of check valves & pumping stations
Floodplain / River corridor Tree planting, Planting of helophytes at the foot of banks
Planform / Channel pattern Channel widening
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/pdf/Vezouze GB BD2.pdf All information on this page is copied from the AFB, The French Agency for biodiversity.

Supplementary Information

Edit Supplementary Information