General
National Id
Switzerland_01
Site name
Seymaz river
Summary
The Seymaz renaturation project takes place in Switzerland, along the Seymaz river which is located in the eastern part of Geneva canton. The project consists in several renaturation measures: eliminating concrete casts, softing riverbanks and widening riverbed. A wetland (marshland) is also re-created. The project is part of the cantonal program which aims at improving ecological and countryside quality and reducing flood risk by managing peakflows. Two stakeholders groups have been involved in the project implementation: the Charte Seymaz group (“negociation” group on the renaturation program which include all concerned stakeholders) and the management group (Responsible for coordinating and managing the local arrangements). A main constraint of the project have been the nature of land use and property in the area concerned by the NWRM, since famers were mostly impacted by the project and first opposed to it.
The in-depth description of the case study
NUTS Code
Ticino
RBD code
CH50
Transboundary
0
Data provider
Anaïs HANUS, ACTeon
Source(s)
NWRM(s) implemented in the case study
Longitude
6.180665
Latitude
46.198248
Site information
Climate zone
cool temperate moist
Mean rainfall
971
Mean rainfall unit
mm/year
Average temperature
9,80000019073486
Average imperviousness
0,0900000035762787
Type
Case Study Info
Light or indepth?
In-depth
Average slope range
1-2%
Vegetation class
Agricultural land use includes cereals, and some vineyards and vegetable crops. Artificial land is mostly for residential use.
Monitoring maintenance
Monitoring impacts effects
1
Monitoring location
In-Stream
Monitoring parameters
Water flows are measured in different sites of Seymaz river (at least 3). Temperature and ecological status have been studies punctually.
Water quality is monitored:
- physic-chimical quality through parameters: nitrogen, phosphorous, metal, pesticides, organic carbon
- ecological quality through two parameters: benthic macrofauna and diatomees
Water quality is monitored:
- physic-chimical quality through parameters: nitrogen, phosphorous, metal, pesticides, organic carbon
- ecological quality through two parameters: benthic macrofauna and diatomees
Performance
Performance impact estimation method
Catchment outlet
Performance impact estimation information
physic-chimical quality is measured every 6 years and ecological quality between every 1 to every 8 years
Design & implementations
Application scale
River
Installation date
2005-01
Age
7
Performance timescale
1 - 4 years
Area (ha)
2920
Area subject to Land use change or Management/Practice change (ha)
400
Size
5,09999990463257
Size unit
km
Design capacity description
About 800 000m3 can be retained in the treated area thanks to several NWRM and some other retention ponds.
Constraints
Main contraints concerned land use, mostly agricultural lands, which was to be impacted by the project
Favourable preconditions
Seymaz river basin used to be partly a wetland before being drained; natural hydrology could be restored
Management change from
cereal cropping
Management change to
natural land management
Outflow volume
4
Outflow volume unit
m3/sec
Peak flow rate
15,5
Public consultation
1
Design contractual arrangement
| Arrangement type | Responsibility | Role | Comments | Name | |
|---|---|---|---|---|---|
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Contractual agreement
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Contrats Nature
|
Design consultation activity
| Activity stage | Key issues | Name | Comments | |
|---|---|---|---|---|
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Design phase
|
Charte Seymaz
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Implementation phase
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Design land use change
| Land use change type | |
|---|---|
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Natural grasslands
|
Design authority
| Authority type | Role | Responsibility | Name | Comments | |
|---|---|---|---|---|---|
Lessons, risks, implications...
Key lessons
The project has enabled land use regulation through social solidarity and economic efficiency, taking local interests into account in addition to global interests (regarding floods and biodiversity). This can have facilitated the acceptation and success of its implementation.
Moreover, the measure happens to be more cost-efficient than previous projects of flood regulation.
Moreover, the measure happens to be more cost-efficient than previous projects of flood regulation.
Financing mechanism
1
Financing mechanism information
Compensation schema: farm owners and farmers have received financial compensation, either for selling their land or keeping it and managing it respecting a †œnature contract†. The payment was function of the number of concerned hectares. Moreover, punctual compensations have been done, for instance during works periods and for a loss of three year yields during when land was leveled. Farmers also beneficiated for tax advantages.
The State also created a fund for regional agriculture promotion, beneficiating for land sales. The renaturation department transferred 1,9million CHF to this fund.
The State also created a fund for regional agriculture promotion, beneficiating for land sales. The renaturation department transferred 1,9million CHF to this fund.
Financing difficulties
0
Success factor(s)
| Success factor type | Success factor role | Comments | |
|---|---|---|---|
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Existing institutional framework
|
main factor
|
Main success factors have been: - the local political context, much more in favor of renaturation than other cantons (laws, fund...) - local arrangements such as the †œdrainage right† given t farmers - the high participation rate of farmers and other actors in the process decision and implementation (through Charte Seymaz group) |
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Specific incentives for stakeholder involvement
|
secondary factor
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Financing possibilities
|
main factor
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Public participation
|
main factor
|
Financing
| Financing type | Comments | |
|---|---|---|
|
Local funds
|
The main funding sources were:
- the cantonal renaturation fund (45millions CHF) - the two laws on renaturation voted by Geneve State (27 million CHF) Incentives were used through compensations forward famers who sold their land or sign in a †œnature contract† regarding the way to manage it. Private funding has been made |
Driver
| Driver type | Driver role | Comments | |
|---|---|---|---|
|
Past flooding events
|
main driver
|
Land use constraints have been the initiator factor to the implementation of the measure, since frequent floods happened to occur on farmlands in the Seymaz basin itself, linked to the artificialisation of the river during the past centuries. Floods in the urban areas downstream were already a problem.
Political context, legislation and existing funding sources have been a main factor leading the choice for the implementation of the NWRM, instead of †œtraditional† works for flood management. |
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Organisation committed to it
|
secondary driver
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Availability of subsidies
|
secondary driver
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Financing share
| Financing share type | Share | Comments | |
|---|---|---|---|
Policy, general governance and design targets
Policy description
The Seymaz renaturation project is part of the cantonal program which aims at improving ecological and countryside quality and reducing flood risk by managing peakflows.. Corresponding WFD pressures are:
4.1.2 Physical alteration of channel/bed/riparian area/shore of water body for agriculture
4.3.1 Flow diversions/hydrological alteration †“ agriculture
4.3.1 Flow diversions/hydrological alteration †“ agriculture
4.1.2 Physical alteration of channel/bed/riparian area/shore of water body for agriculture
4.3.1 Flow diversions/hydrological alteration †“ agriculture
4.3.1 Flow diversions/hydrological alteration †“ agriculture
Policy target
| Target purpose | |
|---|---|
|
Improved Biodiversity
|
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Runoff control
|
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Increase Water Storage
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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 | |
|---|---|---|---|---|
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Local
|
Environment & Biodiversity
|
Renaturation framework Action Plan
|
The project aims at improving rivers ecological and landscape quality and reducing flood risks. Those requirements are mentioned by a federal legislation (Law on rivers amenagements in 1991 and ordonance on water protection in 1998) and aimed by the program implemented by Geneve State (Renaturation framework Action Plan in 1999).
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Water
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Policy requirement directive
| Requirement directive | Specification |
|---|
Socio-economic
Direct benefits information
Benefits are:
- Flood security and protection: reduction of flood damages in urban areas (houses, school, roads...)
- creation of a touristic area for the inhabitants of Geneve canton. The area now benefits from a positive image which has a positive impact on tourism.
- landscape conservation
- Flood security and protection: reduction of flood damages in urban areas (houses, school, roads...)
- creation of a touristic area for the inhabitants of Geneve canton. The area now benefits from a positive image which has a positive impact on tourism.
- landscape conservation
Ancillary benefits information
Indirect benefits are:
- benefit for farmers by selling products on their farm from this increasing number of visitors
- employment (agritourism, works)
- benefit for farmers by selling products on their farm from this increasing number of visitors
- employment (agritourism, works)
Costs investment
23600000
Costs capital
22000000
Costs capital information
Investments financed by specific laws on renaturation
Costs land acquisition
1600000
Costs land acquisition unit
€ (total value)
Costs land acquisition information
This amount was transferred from the renaturation department to the regional,agriculture promotion fund in order to finance compensations linked to losses of agricultural lands
Costs operation maintenance
37000000
Costs operation maintenance
Including:
15 million € for works financed by Cantonal renaturation fund
22 million € for functioning
15 million € for works financed by Cantonal renaturation fund
22 million € for functioning
Costs operational
37000000
Costs total
61000000
Compensations annual
230000
Compensations annual information
Total amount was of 1,6million€.
Compensations basis unit
€/ha
Compensations basis information
The price for compensations was:
1,6€/m2 for farmers (owners or not)
And 819€/ha more for farmers who didn't sell their lands
1,6€/m2 for farmers (owners or not)
And 819€/ha more for farmers who didn't sell their lands
Compensations scheme information
Compensation schema: farm owners and farmers have received financial compensation, either for selling their land or keeping it and managing it respecting a †œnature contract†. The payment was function of the number of concerned hectares. Moreover, punctual compensations have been done, for instance during works periods and for a loss of three year yields during when land was leveled. Farmers also beneficiated for tax advantages.
The State also created a fund for regional agriculture promotion, beneficiating for land sales. The renaturation department transferred 1,6million € to this fund.
The State also created a fund for regional agriculture promotion, beneficiating for land sales. The renaturation department transferred 1,6million € to this fund.
Ecosystem improved biodiversity
1
Information on Ecosystem improved biodiversity
Seymaz renaturation have recreated a wetland habitat which acts as a refuge for fauna and is a resting place for migratory birds. Flora such as rubanier dressé, laí®che faux souchet, scrofulaire auriculée, samole de Valerand and lagratiole officinale can now be observed in the wetland. Such species are priority in Switzerland and concerned by specific action palns. Farm plants such as bleuet, épiaire annuelle, véronique luisante, linaire élatine, linaire bâtarde, renoncule scélérate and bident triparti are also observed. Seymaz river is also recognized as a nesting site for amphibians.
Ecosystem provisioning services
0
Ecosystem water supply
0
Ecosystem impact climate regulation
No information available
Biophysical impacts
Information on increased water storage
800000m3
Ecosystem erosion control
1
Information on Ecosystem erosion control
Infiltration in riverbeds is higher. Erosion is limited but enough for ecosystems.
Water quality overall improvements
Positive impact-WQ improvement
Information on Water quality overall improvements
Water quality have improved after renaturation (from medium to good) but it still needs to be monitored.
Soil quality overall soil improvements
N/A info
The State also created a fund for regional agriculture promotion, beneficiating for land sales. The renaturation department transferred 1,9million CHF to this fund.