General
National Id
France 05 light
Site name
Ill between Colmar and Strasbourg
Summary
Next to the Ill river in Alsace, France, a project has been initiated which combines classical flood protection (e.g. dyke construction) with natural water retention measures (e.g. riparian buffers). The project aims at reducing peak flows, increasing water storage, controling erosion and improving biodiversity. It has been initiated by the Alsace Region.
NUTS Code
Alsace
RBD code
FRC
Transboundary
0
Data provider
Sabine Tutte, ACTeon
Source(s)
NWRM(s) implemented in the case study
Longitude
7.747882
Latitude
48.583148
Site information
Climate zone
cool temperate dry
Mean rainfall
550
Mean rainfall unit
mm/year
Average temperature
10
Mean runoff
58
Mean runoff unit
600 - 750 mm
Type
Modelled/Simulated Example
Light or indepth?
Light
Monitoring maintenance
Monitoring impacts effects
0
Monitoring location
In-Stream
Administrative annual costs
340000
Monitoring parameters
Stations for counting fish are installed next to barrages and hydropower plants.
Performance
Performance impact estimation information
No information available
Design & implementations
Application scale
River
Performance timescale
Immediate
Area (ha)
12000
Constraints
Partly dams have to be constructed or reinforced, otherwise the risk of severe inundation would not be justifiable. In order to maintain the natural mobility of the river, land of farmers has to be reallocated.
Contractural arrangements
0
Design contractual arrangement
| Arrangement type | Responsibility | Role | Comments | Name | |
|---|---|---|---|---|---|
|
The project has to pass the autorisation steps of the French Water Law. Moreover it has to be proven that the project is of public utility and of public interest in order to mobilize national funds
|
Design consultation activity
| Activity stage | Key issues | Name | Comments | |
|---|---|---|---|---|
|
Implementation phase
|
This is foreseen in project planning in order to educate the public.
|
Guide "rights and duties of riparians"
|
Design land use change
| Land use change type |
|---|
Design authority
| Authority type | Role | Responsibility | Name | Comments | |
|---|---|---|---|---|---|
Lessons, risks, implications...
Key lessons
This management plan combines classical flood protection measures (construction of dykes, automatisation/optimization of barrages) with NWRM. Since the plan is not fully implemented yet, it is difficult to have information on success (especially quantitative data) and monitoring. However, ecosystem services are taken into account to justify the measures.
Financing difficulties information
Since the project is in the implementation phase, there is no sufficient information.
Success factor(s)
| Success factor type | Success factor role | Comments | |
|---|---|---|---|
|
Since the project is in the implementation phase, there is no sufficient information. |
Financing
| Financing type | Comments | |
|---|---|---|
|
EU-funds: Rural development funds
|
Support of sustainable farming (crop rotation, green cover...).
|
|
|
Local funds
|
Renovation of dykes, touristic development.
|
|
|
Sub-national funds
|
Publicity, support of hydropower, touristic development.
|
|
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Sub-national funds
|
Renovation of barrages, NWRM, Agro-environmental measures.
|
|
|
National funds
|
Support of hydropower projects.
|
Driver
| Driver type | Driver role | Comments | |
|---|---|---|---|
|
Legal obligations
|
main driver
|
The good ecological status of the Ill has to be achieved.
|
|
|
Past flooding events
|
main driver
|
Due to regular floods in winter and spring there are severe damages on pastures and fields. Valuable agricultural land is lost (approx. 150 ha in 10 years). Agriculture is a very important economic branch with a gross margin of 16 million €
|
|
|
Public pressure
|
main driver
|
Flood protection is partly missing for entire villages (Kogenheim 1000 inhabitants). Dykes have weak points and need to be renovated.
|
|
|
Balancing different objectives
|
secondary driver
|
Water and terrestrial hiking pathways are missing. Barrages are not passable, and dangerous due to a lack of signalisation. Fishing associations wish a better accessibility to the river.
|
Financing share
| Financing share type | Share | Comments | |
|---|---|---|---|
Policy, general governance and design targets
Policy description
The flood protection of commuities and fields is partly unsufficient. Due to erosion there is a remarkable loss of usable agricultural surface. Barrages and hydropower plants disturb the sediment transport of the river and are not passable for fish and boats. A natural alluvial forest is often missing and shall be restored for water quality improvement and fight against invasive species.
Quantified objectives
The flood protection for some communities is missing, barrages and hydropower plants are not passable for fish and boats. The mobility of the river shall be preserved without encouraging further erosion. Therefore a land allocation process starts, alluvial forests are planted (68 km) and where possible barrages and bank stabilisations are deconstructed. Moreover, 15 hydraulic annexes are reconnected to the river in order to improve water storage capacity and solve water distribution problems. A discharge rill is constructed to the forest near Colmar in order to inundate the wood during flood events and protect fields and communities.
Part of wider plan
0
Policy target
| Target purpose | |
|---|---|
|
Peak-flow reduction
|
|
|
Increase Water Storage
|
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Erosion Control
|
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|
Improved Biodiversity
|
|
|
Oher Societal Benefits
|
Policy pressure
| Pressure directive | Relevant pressure |
|---|
Policy area
| Policy area type | Policy area focus | Name | Comments |
|---|
Policy impact
| Impact directive | Relevant impact |
|---|
Policy wider plan
| Wider plan type | Wider plan focus | Name | Comments |
|---|
Policy requirement directive
| Requirement directive | Specification |
|---|
Socio-economic
Direct benefits information
During the project the tourism branch is supported by improved water/ terrestrial trekking ways, better recreational spaces (bivouacs, camping, hotel restaurant access).
Ancillary benefits information
Without the management plan, 6.1 - 8 Mio € per year have to be foreseen as costs for floods.
Costs investment
12500000
Costs investment information
10 to 15 million Euros: plantation of forests, land acquisition, dyke renovation.
Costs operation maintenance
No data available
Costs total
25500000
Costs total information
19 to 32 million Euros: Next to NWRMs, construction costs for dykes and improvement of barrages and facilities appear. Moreover, the touristic branch is supported by several projects, and hydropower is encouraged as well.
Compensations annual
2000000
Compensations annual information
Support of farmers by agro-environmental measures (encouragement of green cover, pastures, meadows, crop rotation).
Compensations scheme information
The agricultural compensations made in the context of EU CAP Pillar 2.
Economic costs additional
300000
Information on Ecosystem improved biodiversity
Control campaigns for Himalayan Balsam and Japanese Knotweed; plantation of alluvial forests (high species diversity due to diverse habitats).
Information on Ecosystem provisioning services
Better efficiency of hydropower plants due to improved sediment balance.
Information on Ecosystem impact climate regulation
No information available
Biophysical impacts
Information on retained water
By reconnecting hydraulic annexes, installing discharge rills to flood forests and reallocation of land neighboring the river, the water retention capacity gets increased.
Information on runoff reduction
This shall be achieved by natural bank stabilisation and deconstruction of old barrages. By purchasing land a "mobility space" for the river shall be guaranteed.
Information on Maintenance baseflow
This shall be achieved by automatisation of barrages and optimized operation.
Information on Restoring hydraulic connections
Connections are restored.
Water quality overall improvements
N/A info
Information on Water quality overall improvements
This shall be achieved by restoring 68 km of alluvial forests next to the Ill.
Soil quality overall soil improvements
N/A info
