Floodbreaking hedgerows in Southern France

National Id
Site name
Lèze River Basin
The Lèze is a river located in the South of France, near the Pyrenees, on the French departments Ariège and Haute-Garonne. The case study concerns the implementation of floodbreaking hedges, which are located across the flood plain of the Lèze and are regularly spaced (every 300 to 500 metres). Partially obstructing the flow, such hedges can slow down running water and dissipate its energy. The project has been financed by the SMIVAL (20%), French State, local authorities, ERDF and the Water Agency (80% for all).
The in-depth description of the case study
RBD code
Data provider
Guillaume MICHEL, ACTeon
NWRM(s) implemented in the case study
Climate zone
cool temperate moist
Mean rainfall
Mean rainfall unit
Average temperature
Mean runoff
Mean runoff unit
600 - 750 mm
Average runoff coefficient
Case Study Info
Light or indepth?
Monitoring impacts effects
Administrative annual costs
Administrative annual cost information
For the period 2006-2011, costs for facilitation (all actions including floodbreaking hedgerows) supported by the SMIVAL amounted to 326 336 € (ranging from 21 855 € in 2006 to 70 655 in 2009). In comparison to other actions implemented by the SMIVAL, floodbreaking hedgerows represent only a small share of SMIVALs budget (1.4 %). It can hence be assumed that facilitation costs related to floodbreaking hedgerows represent also only a small share of the total facilitation costs.
Performance impact estimation method
Performance impact estimation information
No performance evaluation
Application scale
River Basin
Installation date
Performance timescale
5 - 10 years
Area (ha)
Area subject to Land use change or Management/Practice change (ha)
Size unit
Design capacity unit
Presence of irrigation or drainage equipement
Peak flow rate
Public consultation
Contractural arrangements
Design contractual arrangement
Arrangement type Responsibility Role Comments Name
Organisational arrangement
Protocol between the SMIVAL and the Chambers of agriculture defining land policy (for example purchase of arable land for hedge planting)
Four options are available to farmers: agreement with the SMIVAL, servitude, renting and buying
Protocol for land policy
Contractual agreement
The Framework agreement has been signed in August 2008 by the SMIVAL and its partners (French State, Adour-Garonne Water Agency, Regional council, General councils of Ariège and Haute-Garonne). This Framework agreement works for the implementation of all actions included in the PAPI for the period 2008-2016.
Framework agreement
Design consultation activity
Activity stage Key issues Name Comments
Public meetings
Several public meetings took place from 2009. They aimed at presenting the actions programme (including hedgerows) to the inhabitants. For each meeting, about 20 participants were presents. The SMIVAL also met inhabitants and local associatiations.
Meetings with farmers
Numerous meetings took place with farmers and landowners who may be concerned by planting floodbreaking hedges. The main issue was to explain implementation of this action and to define the associated land policy.
Consultation with local authorities
In 2009, local authorities (mayors) have been met in order to know about the implementation of the actions programme (including hedges) at the villages' level. Mayors also had the opportunity to express their expectations.
Consultation with technicals
The two local Chambers of agriculture are involved in defining the protocole regarding the land policy. Technical partners (for example deconcentrate technical state services and water related public agencies) have been consulted by the SMIVAL when actions of the PAPI have been presented and implemented.
Public inquiry
A public inquiry has been carried out in 2011. The response brief has been published in August 2011.
Design land use change
Land use change type
Design authority
Authority type Role Responsibility Name Comments
Local water authority
Initiation of the measure
SMIVAL (Syndicat Mixte Interdépartemental de la Vallée de la Lèze)
The SMIVAL (Syndicat Mixte Interdépartemental de la Vallée de la Lèze - an association of 24 communes localised in the Lèze's valley) has been created in 2003. It is responsible for leading, for defining and for implementing actions for a qualitative and quantitative use of the Lèze and its tributaries and for preventing its floods.
Determination of design details of the measure
Chambres d'agriculture
Technical Committee
The Technical Committee supervises the implementation of the PAPI. It is presided by a sub-prefect and the president of the SMIVAL. Techical Committee includes the SMIVAL, local authorities, deconcentrate technical state services, public agencies for water management (Onema, Agence de l'eau Adour-Garonne) Chambers of agriculture.
Key lessons
This case study shows the implementation of floodbreaking hedges across the flood plain of the Lèze, a river in the South of France. A land policy has been agreed with farmers and land owners for the implementation of the hedges as well as numerous participation activities.
Success factor(s)
Success factor type Success factor role Comments
Attitude of relevant stakeholders
main factor

An enabling factor for involving local stakeholders is the overlap of global issues and local events. For example, the involvement of farmers is higher when they see mudslides in their fields than when they hear about slowing down the peak flow.

Financing type Comments
National funds
For the period 2007-2011: 4 425 € from the French state.
For the period 2007-2011: 8970 € from SMIVAL (self-financing; each member of the SMIVAL is involved in its financing).
Local funds
For the period 2007-2011: 1008 € from the General Council and 2144 € from the Regional Council.
EU-funds: Cohesion and regional development funds
For the period 2007-2011: 456 € from the ERDF programme.
For the period 2007-2011: 5306 € from the Adour-Garonne Water Agency.
Barrier type Barrier role Comments
secondary barrier
Access is difficult to data about farmers possessing land in the Lèze valley. It is therefore more difficult for the SMIVAL to target these farmers and to invite them to meetings, for example. This information is confidential and cannot be easily spread.
Attitude of relevant stakeholders
main barrier
Implementation of floodbreaks is based on voluntary farmers.
Driver type Driver role Comments
Financing share
Financing share type Share Comments
European funds
According to the activity report 2012, financing from the FEDER programme was still ongoing when the report was written.
National funds
Private funds
For the period 2007-2011, 40,2 % of financing comes from the SMIVAL. Up to April 2014, financing from the SMIVAL represents about 20 % of the total financing.
Policy description
The main targeted problem is flood. Floodbreak hedgerows aim at slowing down flood peaks. Hedgerows are located across the flood plain, perpendicular to the river, and they are regularly spaced every 300 to 500 metres.
Part of wider plan
Policy target
Target purpose
Peak-flow reduction
Runoff control
Erosion Control
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
PAPI de la Lèze : Programme d'Actions de prévention contre les inondations de la Lèze (Actions Programme for preventing floods of the Lèze river)
The PAPI is an action programme designed for fighting floods in the Lèze river bassin. Planting floodbreaking hedgerows is one of these actions. The PAPI has been approved by the French Ministry for Ecology, Sustainable Development and Territorial Planning.
Policy requirement directive
Requirement directive Specification
Costs land acquisition
Costs land acquisition unit
Costs land acquisition information
Four types of agreements with the SMIVAL were proposed to farmers and land owners. For one option, the SMIVAL had to buy the land from the owner. The price of land depends on the crop (arable lands or permanent grasslands) and on the département. In Ariège, prices are 5000 €/ha for arable land and 2500 €/ha for permanent meadows. In Haute-Garonne they reach 6000 €/ha and 3000 €/ha, respectively.
This option was never chosen by land owners.
Costs total
Costs total information
Financing comes from the French State, the SMIVAL, local authorities, ERDF and the Water Agency. Up to now, about 75 000 € have been spent for floodbreaks. About 20 % of the financing comes from the SMIVAL and 80 % from other financing partners.

Between 2009 and 2012, 3020 linear metres of hedgerows have been planted (including 520 linear metres for the two test hedgerows) for a total cost of 47 870 € (costs for hedgerows which have been planted later are not taken into account).
Costs are distributed as follow:
- Technical study: 9 240 € in 2007
- First test hedge (in Montaud): 4 221 € in 2008 and 3 532 € in 2009
- Second test hedge (in Artigat): 3 420 € in 2010
- Hedge planting 2011-2012: 27 456 € in 2011 and 2012
Cost of one linear metre of hedge : 11 € as planned by the PAPI. But for the test hedgerows, costs reached 45 to 60 € per linear metre.
Compensations annual information
Payment depends on the agreement between farmers/landowners and the SMIVAL. In some cases, there is no payment. There may be a payment to landowners when arable land is bought or rent by the SMIVAL. There may also be a payment to farmers when new hedgerows disturb the organisation of the farmer.
Compensations nr beneficiaries information
Landowners and/or farmers. There is no number available.
Compensations scheme information
Payment depends on the agreement between farmers/landowners and the SMIVAL. In some case, there are no payment. There may be a payment to landowners when arable land is bought or rent by the SMIVAL. There may also be a payment to farmer when new hedgerows disturb the organisation of the farmer.
Information on Ecosystem improved biodiversity
N/A info
Ecosystem provisioning services
Information on Ecosystem provisioning services
Provision of wood and food (fruit trees in the hedges).
Information on Ecosystem water supply
N/A info
Ecosystem impact climate regulation
Not relevant for the specific application
Information on Peak flow rate reduction
According to a hydrological model: In the case where the flood plain of the Lèze would be covered by regularly spaced floodbreaking hedgerows, the peak flow of flood events could be reduced by 25% in comparison to the same river basin with field crops. In fact, the river basin already has hedges (about 900 km) and it will not be possible to achieve a landscape with a very dense network of hedges. The model only shows a trend.
Ecosystem erosion control
Information on Ecosystem erosion control
Slowing down water runoff should help to decrease soil erosion in the flooding plain.
Water quality overall improvements
Not relevant for this application
Information on Ecosystem erosion control impact
Local positive impacts on soil erosion can be seen, but there is no assessment nor quantification
Soil quality overall soil improvements
Not relevant for this application


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